More stories

  • in

    Tests of rubber granules used as artificial turf for football fields in terms of toxicity to human health and the environment

    Description of test samples and theirs preparation84 samples of recycled rubber granules with a particle size of 0.5 to 4 mm, produced for the construction of sport field surfaces, were tested. The samples of rubber granules were collected from 17 sport fields and 67 samples rubber granules were supplied by recyclers. Research included 57 samples of SBR granules and 27 samples of EPDM granules. The numbers of samples in relation to their sources of origin are shown in Fig. 1.Figure 1Number of samples of the tested SBR and EPDM granules in relation to their sources of origin.Full size imageThe samples were taken from the surface of sport fields with artificial turf in accordance with the laboratory instructions or delivered to the laboratory by recyclers. The mass of the granulate samples delivered for testing was approx. 0.5 kg. Sampling from sport fields was carried out using a scheme based on 6 sampling points, shown in Fig. 2, in accordance with point 4 of the FIFA guidelines: “Quality Programme for Football Turf. Handbook of Test Methods for Football Turf”. The number and weight of granular samples and the locations of the granular sampling points on the field indicated in the aforementioned guidelines are indicated in order to obtain a representative homogenized granular sample for the tested field42.Figure 2Scheme of distribution of granulate sampling points on a sport field. Designation:
    location and numbers of granulate sampling points.Full size imageAt the designated points (1 ÷ 6), 6 samples of granulate were collected. The collected and secured samples were stabilized in the laboratory conditions of natural drying, in which the moisture of the sample was in equilibrium with the ambient moisture. After stabilization, the samples were purified and homogenized to give a pooled sample. Images of exemplary SBR and EPDM granules used in the study are shown in Fig. 3. The average values of the physical parameters of the tested rubber granules are given in Table 1.Figure 3Samples taken from sport fields: (a) SBR granules, (b) EPDM granules.Full size imageTable 1 Some physical parameters of the tested SBR and EPDM granules (data from the Technical Data Sheets provided by the recyclers).Full size tableSamples weighing at least 100 g were taken from the granulate samples using the quartering method. This way allowed to ensure full qualitative and quantitative compliance of the sample composition with the composition of the analyzed material. Samples for testing the content of PAHs were grounded by grinding in a cryogenic mill 6770 Freezer/Mill, by SPEX SamplePrep LLC. Samples for testing other substances were not crushed.The scope and methods of testing rubber granulesThe scope of the research on rubber granules included: content determination of the PAHs, leached elements, organotin compounds and PAHs. In all samples of rubber granules, the content of 8 polycyclic aromatic hydrocarbons, resulting from the REACH Regulation, was determined: benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBAhA), benzo[e]pyrene (BeP), benz[a]anthracene (BaA), chrysene (CHR), benzo[b]fluoranthene (BbFA), benzo[j]fluoranthene (BjFA) and benzo[k]fluoranthene (BkFA). The content of indeno[1,2,3-cd]pyrene (IcdP), benzo[ghi]perylene (BghiP), phenanthrene, anthracene, fluoranthene, pyrene and naphthalene was determined for 38 samples from recyclers, additionally, that the number of PAHs covered by the requirements of the document43 was increased by 7.The leaching tests of elements and organotin compounds were carried out for 18 samples and the leachability of PAHs and elements were carried out for 4 samples. The tests were carried out with the methods listed below, using the following apparatus.The content and leachability of PAHs from rubber granules was determined by gas chromatography with tandem mass spectrometry (GC–MS/MS) using a gas chromatograph coupled with a mass detector GCMS/MS/7890B/7000C. The method was chosen because of the high sensitivity and selectivity obtained for low PAHs levels when used GC–MS/MS, compared to other commonly used analytical techniques such as high-performance liquid chromatography (HPLC) combined with UV, fluorescence or diode array detector (DAD). In studies carried out with the use of the above-mentioned techniques trace amount of PAHs identification is easily interfered by sample matrix and other components if only based on retention44.Determination of leaching of elements: Al, Sb, As, Ba, B, Cd, Co, Cu, Pb, Mn, Hg, Cr, Ni, Se, Sr, Sn, Zn and elution of the Cd, total Cr, Pb, Sn, Zn from rubber granules was carried out by the inductively coupled plasma mass spectrometry (ICP-MS) method with the use of Agilent 7900 ICP-MS (Agilent Technology, Santa Clara, CA, USA). The selected method is characterized by a low limit of quantification, which stands out among other instrumental methods used in elemental analysis, such as ICP-OES or AAS (Inductively coupled plasma–optical emission spectrometry or atomic absorption spectrometry). It is also characterized by high sensitivity and precision, selectivity enabling the simultaneous determination of many elements in complex matrices in a wide range of concentrations.Leachability of Cr (III) and Cr (VI) and elution of Cr (VI) from rubber granules were determined by high-performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) using Agilent 7700 Series ICP-MS with Agilent 1260 Infinity series HPLC (Agilent Technology, Santa Clara, CA, USA). The decision to use HPLC in conjunction with ICP-MS was dictated by the need to determine chromium in two oxidation states. In the case of the selected method, the speciation separation of Cr (III) and Cr (VI) takes place on the HPLC column, where Cr (III) and Cr (VI) are adsorbed. In the next step it allows for the separation and determination of Cr (III) and Cr (VI) in the ICP-MS spectrometer. The HPLC-ICP-MS method is characterized by a short analysis time and a low detection limit compared to the other spectrophotometric methods used for determination of Cr (VI). The leaching of organotin compounds was assessed on the basis of the results of total Sn leaching.Cold-vapor atomic absorption spectroscopy (CV-AAS) with the PerkinElmer FIMS 100 mercury analyser was selected for the Hg leaching study due to the use of a unique technique of mercury vapour measurement at room temperature. Among other alternative methods of Hg determination in aqueous solutions (ICP-MS or GF-AAS (graphite furnace atomic absorption spectrometry)), the selected method is distinguished by a low limit of quantification, simple preparation of samples for analysis, easy elimination of interference and short analysis time.Tests of the content of PAHsShredded samples of rubber granules were subjected to the ultrasonic extraction process for 1 h with the use of toluene as a solvent. Samples were taken from the obtained extract for chromatographic analysis. The analysis was carried out for the following conditions: dispenser operation mode: splitless, carrier gas: Helium: 1.8 ml/min, DB-EUPAH column with dimensions: 20 m × 180 µm × 0.14 µm (the 20 m column is in the form of a coiled wire), injection temperature: 275 °C. The PAHs were identified on the basis of mass spectra and retention times—Table 2.Table 2 Target and identification ions and retention times for the determined PAHs.Full size tableTests of the leaching of elements and organotin compoundsSamples of rubber granules for the study of the leaching of organotin elements and compounds were extracted in a solution of hydrochloric acid (HCl), with concentration 0.07 ± 0.005 mol/dm3 in temperature 37 ± 2 °C. Solutions for the determination the Cr(VI) and Cr(III) prepared by diluting the extraction solution to obtain the pH equal to 7.0 ± 0.5 by adding 1 ml of 0.07 mol/dm3 ammonia and 60 µL of 0.1 mol/dm3 EDTA solution. In parallel, a reagent blank was prepared, as the test samples were. The obtained extracts were analyzed by ICP-MS and HPLC-ICP-MS. The analyzes were performed for the isotopes of the elements: Al—27, Sb—121, As—75, Ba—137, B—11, Cd—111, 112, Cr—52, 53, Co—59, Cu—63, Pb—206, 207, 208, Mn—55, Hg—201, Ni—60, Se—78, Sr—88, Sn—118, 120, Zn—64, 66.Tests of the leachability of polycyclic aromatic hydrocarbons (PAHs) and elementsDetermination of the dry mass of the rubber granulate samples for the leachability tests was carried out in accordance with ISO 11465:199945, using a drying oven (Pol-Eco-Apparatus SLW-115 Top, Wodzisław Śląski, Poland) and analytical balances (SARTORIUS, Kostrzyn Wlkp. i Radwag, Radom, Poland).The rubber granulate samples were dynamically washed with deionized water according to EN 12457-4:200246 providing a ratio of 1 ml of liquid to 1 g of rubber granulate. The pH value of the water used for dynamic leaching did not exceed 6.7. Elution was performed using a bottle/tube roller mixer (Thermo scientific model, Thermo Fisher Scientific (China) Co., Ltd., Shanghai China). After washing, the effluents were left for 15 min and then filtered through 0.45 mm membrane filters using a pressure filtration device.The leachate obtained from dynamic leaching was subjected to the process of transferring PAHs from the water phase to the organic phase using the algorithm:

    SPE column: C18 bed—6 ml/1000 mg;

    activation: 10 ml of methanol, 10 ml of methanol:water (40:60) (v:v), flow: 1 ml/min;

    sample:eluting solution of methanol (100 ml:10 ml), flow: 0.5 ml/min;

    drying: minimum 15 min, maximum flow;

    elution: 3 × 3 ml of dichloromethane, flow: 0.5 ml/min.

    Collected filtrates were evaporated using a vacuum evaporator (IKA RV 05 basic, IKA WERKE GMBH & CO.KG, Staufen) up to 1 ml. Evaporated filtrates were subjected to the chromatographic analysis performed for the conditions as for the determination of PAHs content. The content of eluted PAHs and elements was related to dry mass of the rubber granulate in each sample.The devices were calibrated and checked on a current basis, including the analysis of control samples, before starting the measurements. Calibrations of the chromatograph, spectrometer and mercury analyzer were performed on solutions of certified reference materials and 2 control samples. The correlation coefficients obtained during the calibration were above 0.995 for all analyzed substances. The analysis of the control samples confirmed the accuracy of the calibration curves, which are the basis for the calculations. Measurements of the content/leachability of the tested substances were carried out for two parallel samples and a reagent blank sample, taking into account the results obtained from it in the analysis of analytical samples. The arithmetic mean of two parallel determinations was assumed as the result of the analytical measurement. Content/leachability conversions of test substances were performed using the GC–MS/MS MassHunter Workstation Software, LCP MHLauncher HPLC-ICP-MS and ACP-MS software and WinLab32 with an AA mercury analyzer FIMS100. More

  • in

    Machine learning-based global maps of ecological variables and the challenge of assessing them

    The quality of global maps can be assessed in different ways. One way is global assessment where a single statistic is chosen to summarize the quality of the entire map: the map accuracy. For a categorical variable, this can be the probability that for a randomly chosen location on the map, the map value corresponds to the true value. For a continuous variable, it can be the RMSE, describing for a randomly chosen location on the map the expected difference between the mapped value and the true value. When a probability sample, such as a completely spatially random sample, is available for the area for which a global assessment is needed, then map accuracy can be estimated model-free (also called design-based, e.g., by using the unweighted sample mean in case of a completely spatially random sample). This circumvents modeling of spatial correlation because observations are independent by design6,9. This approach is called model-free because no model needs to be assumed about the distribution or correlation of the data: the only source of randomness is the random selection of sample units from a target population. If a probability sample is not available this approach cannot be used, and automatically the accuracy assessment approach becomes model-based10, which involves modeling a spatial process by assuming distributions and taking spatial correlations into account, and choosing estimation methods accordingly.Using naive random n-fold or leave-one-out cross-validation methods (or a simple random train-test split) to assess global model quality (usually equated with map accuracy) makes sense when the data are independent and identically distributed. When this is not the case, dependencies between nearby samples, e.g., in a spatial cluster, are ignored and result in biased, overly optimistic model assessment, as shown in, e.g., Ploton et al.5. Alternative cross-validation approaches such as spatial cross-validation5,11 that control for such dependencies are the only way to overcome this bias. Different spatial cross-validation strategies have been developed in the past few years, all aiming at creating independence between cross-validation folds5,11,12,13. Cross-validation creates prediction situations artificially by leaving out data points and predicting their value from the remaining points. If the aim is to assess the accuracy of a global map, the prediction situations created need to resemble those encountered while predicting the global map from the reference data (see Fig. 1 and discussions in Milà et al.14). This occurs naturally when reference data were obtained by (completely spatially random) probability sampling, but in other cases, this has to be forced for instance by controlling spatial distances (spatial cross-validation). Such forcing, however, is only possible when the distances in space that need to be resembled are available in the reference data. In the extreme case where all reference data come from a single cluster, this is impossible. When all reference data come from a small number of clusters, larger distances are available between clusters but do not provide substantial independent information about variation associated with these distances. Lack of information about larger distances means that we cannot assess the quality of predictions associated with such distances and cannot properly estimate global quality measures. Alternative approaches such as experiments with synthetic data15 or a validation using independent data at a higher level of integration16 would then be options to support confidence in the predictions.Another way of accuracy assessment is local assessment: for every location, a quality measure is reported, again as probability or prediction error. Such a local assessment predicts how close the map value is to newly observed values at particular locations. If the measurement error is quantified explicitly, a smoother, measurement-error-free value may be predicted10. If the model accounts for change of support10,17, predictions errors may refer to average values over larger areas such as 1 × 1, 5 × 5, or 10 × 10 km grid cells. Examples of local assessment in the context of global ecological mapping are modeled prediction errors using Quantile Regression Forests18 or mapped variance of predictions made by ensembles1,2. Neither of these examples quantifies spatial correlation or measurement error, or addresses change of support, as it is known from other modeling frameworks19. By omitting to model the spatial process, the local accuracy estimates as presented in the global studies that motivated this comment are disputable.The difference between global and local assessment is striking, in particular for global maps. A global, single number averages out all variability in prediction errors, and obscures any differences, e.g., between continents or climate zones. It is of little value for interpreting the quality of the map for particular regions. More

  • in

    Same-sex competition and sexual conflict expressed through witchcraft accusations

    The data used here provides evidence that particular relationships may determine sex-specific patterns of witchcraft accusation. Cases where women were targeted frequently came from affinal kin, while those directed at men were often from unrelated individuals and blood relatives. Most previous research on factors that determine the sex of accused ‘witches’ has largely consisted of qualitative studies of a single society or a few societies48, or historical studies that have not tested for correlations49. Our findings, in support of the overarching hypothesis that accusations may be driven by various forms of competition, can be tentatively aligned with evolutionary literature on patterns of intrasexual and kin competition, intersexual conflict and polygamous mating30,31,50.Men were more often accused than women in our sample, although we did not have a prediction in relation to this. But the finding suggests how overall patterns of competition within relationships may contribute to societal ‘phenotypes’ of witches as male or female. The ethnography of the Ndembele perhaps indicates why women were less frequently targeted in Bantu societies: ‘in a case of witchcraft, the complainant is actuated by caprice, jealousy or pique; and the defendant is a person of wealth or popularity, and is always a man, for the women have neither wealth nor honor worth coveting’51.Our predictions about how the sex of accused ‘witches’ might be associated with particular relationship categories were supported. The majority of accusations targeting men came from unrelated individuals, which is unsurprising, as inclusive fitness52 would not mitigate the effects of competition between them. Blood relatives were the next most common relationship category directing accusations at men. This aligns with more recent studies indicating that witchcraft fears between family members are significant in parts of Africa, to the extent that they can be construed as ‘the dark side of kinship’53. In evolutionary terms, kin may compete with one another in environments where resources are limited30,31,50 and in societies with patrilineal inheritance related males, and particularly brothers, compete for resources in order to marry31. This aligns with an ethnographic observation that among the Banyoro witchcraft accusations often occurred between brothers over inheritance, but not between brothers and sisters, whose interests did not conflict21. The situations relating to accusations of men were also often connected to the acquisition of wealth and status, such as rivalry over village headmanships32, power struggles between a chief’s counsellors54 or disputes over inheritance55. These connections can be found in more recent contexts such as twentieth century Ghana, where notions of obtaining political power and wealth through occult means involving human sacrifice were pervasive56.Accusations of women were more likely to come from affines. Husbands were the largest category of affinal kin to accuse women (Supplementary Fig. 2). The higher rate of accusations from husbands to wives than wives to husbands aligns with evolutionary perspectives suggesting male coercion of females is a strategy to maximize male reproductive success39,41. Accusations of wives who were suspected of being unfaithful can be interpreted as a strategy for reducing investment in unrelated offspring35,41. In a case from the Shona a woman gave birth to a stillborn child. This was attributed to an affair before marriage, and was followed by divorce and the repayment of bridewealth to her husband, who commented she was ‘a witch, a woman who had killed her own child’48. Other ethnographic accounts suggest accusations of wives by husbands were an attempt to gain control within the marital relationship55.A significant number of accusations of women by affinal kin were from co-wives in polygynous marriages, and these were often notably associated with jealousy connected to a husband’s attention and investment32. Evolutionary models predict competition for reproductive resources would occur among co-resident breeding women57, as has been found to occur among the Mosuo of southwest China58. In the patrilocal social systems that are predominant in our sample, women disperse at marriage and are isolated from kin, so conflict may be more extreme30. This is consistent with ethnographic observations reporting that the relationship between co-wives in polygynous marriages was often (although not always) marked by conflict, and liable to produce witchcraft accusations38,59.There were accusations of women from other categories of their affinal kin (Supplementary Fig. 2). These again may result from competition for a husband’s time and resources between his kin and wife. New wives may be vulnerable in environments where they enter their husband’s families as unrelated strangers, and are potentially expendable, at least before the arrival of offspring. Some accounts of accusations indicate that accusations of wives by in-laws in patrilocal households are common29.Accusations directed at elderly individuals targeted women more often than men. This may form part of a broader pattern of geronticide: societies close to subsistence-level are documented as sometimes accepting the abandonment or killing of elderly people19,60. In modern Tanzania, ‘witches’ are mostly post-reproductive women, who are more likely to be murdered in periods of income shock19. This is also the case in contemporary Ghana, where accusations are frequently directed at middle-aged or elderly women, whose families may subsequently cease to provide them with financial or material assistance61. In our sample, elderly women may have been targeted more frequently as a result of longer female lifespans: in a polygynous society, men may marry younger women, so wives would be widowed at an earlier age than husbands. Among the Bantu, older men were accused, but some were possibly protected by their status.Accusers’ payoffs from accusations are not always explicit but they can be inferred. The most common outcome of accusations in our sample was that accused ‘witches’ were exiled from their communities or forced to move from where they were living. This would mean resources and cooperative assistance they would have used became available to their accusers or others nearby. Where the accused acquires a negative reputation, which was the second most common outcome, there may be a subtle removal of benefits, which may be preferred to direct ‘punishment’ as it is less costly62. Accusers’ gains need not be direct, as harming behaviours may reduce the overall pressure of competition in an environment28. 8% of accusations in the sample resulted in the acquisition of either resources or political positions from the accused, or in preventing the accused from acquiring them. Where the accused were penalised in other ways, such performing ceremonies to reconcile with accusers, this is perhaps akin to classic cooperation models involving the punishment of defectors (although the accused may not actually be uncooperative)11, providing accusers with subordinate partners who offer fitness benefits to avoid more serious allegations63. Where an accusation does not ‘stick’, ethnographic accounts sometimes indicate it was reversed through divination or ordeal54. In other cases, for various reasons accusations are short-lived and forgotten about4. Finally, although not tested in this dataset, accusers may gain informal prestige and dominance, an outcome analogous to competitive punishment63.Not all of the cases in our dataset support the hypothesis that witchcraft accusations are a mechanism for competition. There is a significant proportion where the accusation of a particular individual appears to be incidental, or dependent a on circumstantial association between the ‘witch’ and a negative event. Such accusations are unlikely to provide accusers with a competitive advantage. There are several possible explanations for such cases. They are in line with the hypothesis that witchcraft belief arises from attempts to identify the cause of an impactful misfortune3,4. Cultural evolutionary explanations of witchcraft beliefs suggest that they are a maladaptive attempt to explain misfortune. Although it is inaccurate, belief in witches is maintained through bias and selective inattention to evidence that would otherwise counter it64. Alternatively this could be viewed under the contention that superstitious beliefs (or errors in attributing cause and effect) are broadly adaptive if they occasionally lead individuals to acts which provide them with fitness benefits65.Although witchcraft accusations may be a mechanism for mitigating the damage to accusers’ reputations in harmful competitive acts, as with any behavioural strategy it is not without risks. Accusers may suffer costs in the form subsequent reputational damage or counter-accusations, as with punishment63, depending on factors such the level of support for an accusation by other members of the community.One limitation of our dataset is that it contains realized allegations of witchcraft, that cannot be tested against baseline population measures. We could not examine the risk that a particular individual, such as an elderly woman, would be accused. Instead, the analysis shows the odds, given an accusation occurred, that the ‘witch’ was male or female, given certain predictors. For example, if the accused was elderly, there are increased odds they were female rather than male.A dataset using historic witchcraft cases is almost certainly affected by selection bias. Cases with sensational outcomes are more likely to be reported, and cases that are dismissed or where the accused removes themselves from their accusers are liable to be overlooked19. Most incidents in our sample were reported anecdotally. Obtaining a random sample of witchcraft accusations within a population is challenging, if not impossible1,66. Attempts to systematically collect cases within a given location and timeframe cannot guarantee that all are brought to the attention of researchers19. Comparative studies of this kind usually use all the data that is available and control for confounding effects. Our sensitivity analyses suggest the large number of accusations of men in the dataset probably reflects patterns of accusations in these societies, rather than male-focused bias from ethnographers. There are many accounts of cultures where witches are predominantly male33,34,49. But the accuracy of historic ethnographic accounts cannot be verified, especially in relation to one-off events such as witchcraft accusations, just as it is unclear how much uncertainty there is in the ethnographic record overall67. Ethnographers may not always have noted the characteristics of the individuals involved, or there may be times where they were mistaken in reporting the circumstances surrounding an accusation. There are several explanations for cases where the identities of accusers or purported victims of witchcraft were not reported. Not all cases had identifiable ‘victims’, for example when the accused was thought to have used witchcraft to promote their own success, or ethnographers could not denote the relationship between the accused and their accusers when suspicions of witchcraft were communicated through general gossip. In a small number of cases, ethnographer perspectives on accusations (and possible inability to access further information) are salient, as they may ascribe more importance to one relationship over another in reporting a case, such as a witch’s envy of their victim, or a witch’s argument with an accuser.However, it is likely that ethnographers were for the most part accurate in documenting variables of interest such as the sex of an accused individual and their relationships with accusers. There is less certainty in relation to the situation connected to an accusation, especially taking into recent research that indicates the prevalence of phenomena such as the misperception of causation68,69. Our attempts to account for such possibilities with sensitivity analyses and meta-data on the production of ethnographies cannot conclusively provide reassurance that bias has not affected results, and so this section of the analysis should be treated with caution and regarded as exploratory. The situations documented in our study do however align with accounts of accusations from more contemporary observers and studies from different geographic locations, suggesting that similar causes of accusations arise convergently in different societies. For example in modern contexts accusations have led to accusers gaining land or property in India6 and cessation of the obligation to provide material and financial assistance to elderly relatives in Ghana61. One advantage of our cross-cultural data being drawn from numerous ethnographies is that it is not reliant on the perspective of one individual, meaning that random perceptual error or individual (as opposed to cultural) bias is more likely to be mitigated in the results than would be the case in the study of a single culture by one ethnographer.As a further limitation, we were reliant on accessible ethnographic records from the best-documented societies. Although selection bias in favour of better described societies is present in our sample, this should not impact the main aim of this research, which is to understand the determinants of witchcraft accusations being directed at male or female targets.Overall our findings may indicate allegations of witchcraft stem from diverse forms of competition between individuals. This aligns with evolutionary approaches to competition and conflict. Accusations may provide fitness benefits by allowing individuals to target competitors, but the exact form and direction of competition is determined by aspects of socio-ecology. This in turn influences which sex is most likely to be accused and the overall portrayal of witches in a society. Accusations may be more likely to occur in some relationships rather than others, when there is a gain for the accuser, as in disputes over inheritance and property, or where another individual may pose a threat, or by simply reducing numbers of competitors. The success of witchcraft accusations in removing competitors and their flexibility as an adaptive strategy may explain their widespread distribution. More

  • in

    Author Correction: Recent expansion of oil palm plantations into carbon-rich forests

    In the version of this article initially published, there were mistakes in affiliations 1, 2 and 6. The corrected affiliations should read as follows: 1. Department of Earth System Science, Ministry of Education Key Laboratory for Earth System Modeling, Institute for Global Change Studies, Tsinghua University, Beijing, China; 2. Ministry of Education Ecological Field Station for East Asian Migratory Birds, Department of Earth System Science, Tsinghua University, Beijing, China; 6. Department of Geography, Department of Earth Sciences, and Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China. The affiliations have been corrected in the HTML and PDF versions of the article. More

  • in

    Allelopathic effects of sesame extracts on seed germination of moso bamboo and identification of potential allelochemicals

    Jiang, Z. H. Bamboo and Rattan in the World (China Forest Publishing House, 2007).
    Google Scholar 
    Zhou, B. Z., Fu, M. Y., Xie, J. Z., Yang, X. S. & Li, Z. C. Ecological functions of bamboo forest: Research and application. J. For. Res. 16, 143–147 (2005).Article 

    Google Scholar 
    Su, W., Fan, S., Zhao, J. & Cai, C. Effects of various fertilization placements on the fate of urea-15N in moso bamboo forests. For. Ecol. Manag. 453, 117632 (2019).Article 

    Google Scholar 
    Zhao, J. et al. Ammonia volatilization and nitrogen runoff losses from moso bamboo forests under different fertilization practices. Can. J. For. Res. 49(3), 213–220 (2019).CAS 
    Article 

    Google Scholar 
    Lima, R. A. F., Rother, D. C., Muler, A. E., Lepsch, I. F. & Rodrigues, R. R. Bamboo overabundance alters forest structure and dynamics in the Atlantic Forest hotspot. Biol. Conserv. 147(1), 32–39 (2012).Article 

    Google Scholar 
    Kobayashi, K., Kitayama, K. & Onoda, Y. A. A simple method to estimate the rate of the bamboo expansion based on one-time measurement of spatial distribution of culms. Ecol. Res. 33(6), 1137–1143 (2018).CAS 
    Article 

    Google Scholar 
    Xu, Q. F. et al. Rapid bamboo invasion (expansion) and its effects on biodiversity and soil processes. Glob. Ecol. Conserv. 21, e00787 (2020).Article 

    Google Scholar 
    Isagi, Y. & Torii, A. Range expansion and its mechanisms in a naturalized bamboo species, Phyllostachys pubescens, Japna. J. Sustain. Forest. 6(1–2), 127–141 (1997).Article 

    Google Scholar 
    Dong, C. L. et al. Effect of new rhizome growth on the fringe of the forest of Phyllostachys heterocycla cv. pubescens by different measure. J. Anhui Agric. Univ. 27(2), 150–153 (2000) (In Chinese with English abstract).
    Google Scholar 
    Bai, S. B. et al. Plant species diversity and dynamics in forests invaded by Moso bamboo (Phyllostachys edulis) in Tianmu Mountain Nature Reserve. Biodivers. Sci. 21(3), 288–295 (2013) (In Chinese with English abstract).Article 

    Google Scholar 
    Lin, Q. Q., Wang, B., Ma, Y. D., Wu, C. Y. & Zhao, M. S. Effects of Phyllostachys pubescens forest expansion on biodiversity in Tianmu Mountain Nature Reserve. J. Northeast Forest Univ. 42(9), 43–47 (2014) (In Chinese with English abstract).
    Google Scholar 
    Okutomi, K., Shinoda, S. & Fukuda, H. Causal analysis of the invasion of broad-leaved forest by bamboo in Japan. J. Veg. Sci. 7(5), 723–728 (1996).Article 

    Google Scholar 
    Ouyang, M. et al. Effects of the expansion of Phyllostachys edulis on species composition, structure and diversity of the secondary evergreen broad-leaved forests. Biodivers. Sci. 24(6), 649–657 (2016) (In Chinese with English abstract).Article 

    Google Scholar 
    Larpkern, P., Moe, S. R. & Totland, Ø. The effects of environmental variables and human disturbance on woody species richness and diversity in a bamboo-deciduous forest in northeastern Thailand. Ecol. Res. 24(1), 147–156 (2009).Article 

    Google Scholar 
    Larpkern, P., Moe, S. R. & Totland, Ø. Bamboo dominance reduces tree regeneration in a disturbed tropical forest. Oecologia 165(1), 161–168 (2011).ADS 
    PubMed 
    Article 

    Google Scholar 
    Griscom, B. W. & Ashton, M. S. A self-perpetuating bamboo disturbance cycle in a neotropical forest. J. Trop. Ecol. 22(5), 587–597 (2006).Article 

    Google Scholar 
    Yin, J. et al. Abandonment lead to structural degradation and changes in carbon allocation patterns in Moso bamboo forests. For. Ecol. Manag. 449, 117449 (2019).Article 

    Google Scholar 
    Suzuki, S. & Nakagoshi, N. Expansion of bamboo forests caused by reduced bamboo-shoot harvest under different natural and artificial conditions. Ecol. Res. 23(4), 641–647 (2008).Article 

    Google Scholar 
    Cai, L., Zhang, R. L., Li, C. F. & Ding, Y. A method to inhabit the expansion of Phyllostachys pubescens stands based on the analysis of underground rhizome. J. Northeast Forest Univ. 31(5), 68–70 (2003) (In Chinese with English abstract).
    Google Scholar 
    Rice, E. L. Allelopathy (Academic Press, 1984).
    Google Scholar 
    Huang, W. et al. Allelopathic effects of Cinnamomum septentrionale leaf litter on Eucalyptus grandis saplings. Glob. Ecol. Conserv. 21, e00872 (2020).Article 

    Google Scholar 
    Turk, M. A. & Tawaha, A. M. Allelopathic effect of black mustard (Brassica nigra L.) on germination and growth of wild oat (Avena fatua L.). Crop Prot. 22(4), 673–677 (2003).Article 

    Google Scholar 
    Kong, C. H., Li, H. B., Hu, F., Xu, X. H. & Wang, P. Allelochemicals released by rice roots and residues in soil. Plant Soil 288(1–2), 47–56 (2006).CAS 
    Article 

    Google Scholar 
    Duke, S. O. Weeding with allelochemicals and allelopathy-a commentary. Pest Manag. Sci. 63(4), 307–307 (2007).CAS 
    PubMed 
    Article 

    Google Scholar 
    Braine, J. W., Curcio, G. R., Wachowicz, C. M. & Hansel, F. A. Allelopathic effects of Araucaria angustifolia needle extracts in the growth of Lactuca sativa seeds. J. For. Res. 17(5), 440–445 (2012).CAS 
    Article 

    Google Scholar 
    Soltys, D., Krasuska, U., Bogatek, R. & Gniazdowska, A. Allelochemicals as bioherbicides-present and perspectives. In Herbicides-current research and case studies in use (eds Price, A. J. & Kelton, J. A.) (IntechOpen, 2013).
    Google Scholar 
    Qin, J. H. et al. Allelopathic effects of the different allelochemical pathways of sesame extracts. J. Foshan Univ. 31(4), 1–5 (2013) (In Chinese with English abstract).
    Google Scholar 
    Khasabulli, B. D., Musyimi, D. M., George, O. & Gichuhi, M. N. Allelopathic effect of Bidens Pilosa on seed germination and growth of Amaranthus Dubius. J. Asian Sci. Res. 8(3), 103–112 (2018).
    Google Scholar 
    Boter, M. et al. An integrative approach to analyze seed germination in Brassica napus. Front. Plant Sci. 10, 1342 (2019).ADS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Saha, D., Marble, S. C. & Pearson, B. J. Allelopathic effects of common landscape and nursery mulch materials on weed control. Front. Plant Sci. 9, 733 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Bachheti, A., Sharma, A., Bachheti, R. K., Husen, A. & Pandey, D. P. Plant allelochemicals and their various applications. In Co-Evolution of Secondary Metabolites Reference Series in Phytochemistry (eds Mérillon, J. M. & Ramawat, K.) (Springer, 2020).
    Google Scholar 
    Duary, B. Effect of leaf extract of sesame (Sesamum indicum L.) on germination and seedling growth of blackgram (Vigna mungo L.) and rice (Oryza sativa L.). Allelopathy J. 10(2), 153–156 (2002).
    Google Scholar 
    Soleymani, A. & Shahrajabian, M. H. Study of allelopathic effects of sesame (Sesamum indicum) on canola (Brassica napus) growth and germination. Intl. J. Agri. Crop Sci. 4(4), 183–186 (2012).
    Google Scholar 
    Gorai, M., Aloui, W. E., Yang, X. & Neffati, M. Toward understanding the ecological role of mucilage in seed germination of a desert shrub Henophyton desert: Interactive effects of temperature, salinity and osmotic stress. Plant Soil 374(1–2), 727–738 (2014).CAS 
    Article 

    Google Scholar 
    Wang, C., Wu, B. & Jiang, K. Allelopathic effects of Canada goldenrod leaf extracts on the seed germination and seedling growth of lettuce reinforced under salt stress. Ecotoxicology 28, 103–116 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Wang, X. L. et al. Allelopathic effects of exotic mangrove species Laguncularia racemosa on Bruguiera gymnorhiza. J. Xiamen Univ. 56(3), 339–345 (2017) (In Chinese with English abstract).
    Google Scholar 
    Shah, A. N. et al. Allelopathic influence of sesame and green gram intercrops on cotton in a replacement series. Clean: Soil, Air, Water 45(1), 1–10 (2017).
    Google Scholar 
    Amare, T. Allelopathic effect of aqueous extracts of parthenium (Parthenium hysterophorus L.) parts on seed germination and seedling growth of maize (Zea mays L.). J. Agric. Crop 4(12), 157–163 (2018).
    Google Scholar 
    Yan, X. F., Du, Q., Fang, S. & Zhou, L. B. Allelopathic effects of water extraction of Rhus typhina on Zea mays seeds germination. Seed 29(3), 15–18 (2010) (In Chinese with English abstract).
    Google Scholar 
    Yan, X. F., Zhou, Y. F. & Du, Q. Allelopathic effects of water extraction from root and leaf litter of Rhus typhina on the germination of wheat seeds. Seed 30(5), 17–20 (2011) (In Chinese with English abstract).
    Google Scholar 
    Wang, X. et al. Allelopathic effects of aqueous leaf extracts from four shrub specious on seed germination and initial growth of Amygdalus pedunculata Pall. Forests 9, 711 (2018).Article 

    Google Scholar 
    Alencar, N. L. M. et al. Ultrastructural and biochemical changes induced by salt stress in Jatropha curcas seeds during germination and seedling development. Funct. Plant Biol. 42(9), 865–874 (2015).CAS 
    PubMed 
    Article 

    Google Scholar 
    Lozano-Isla, F., Campos, M. L. O., Endres, L., Bezerra-Neto, E. & Pompelli, M. F. Effects of seed storage time and salt stress on the germination of Jatropha curcas L. Ind. Crop Prod. 118, 214–224 (2018).CAS 
    Article 

    Google Scholar 
    Wu, J. R., Chen, Z. Q. & Peng, S. L. Allelopathic potential of invasive weeds: Alternanthera philoxeroide, Ipomoea cairica and Spartina alterniflora. Allelopathy J. 17(2), 279–285 (2006).
    Google Scholar 
    Sahu, A. & Devkota, A. Allelopathic effects of aqueous extract of leaves of Mikania micrantha H.B.K. on seed germination and seedling growth of Oryza sativa L. and Raphanus sativus L. Sci. World 11(11), 70–77 (2013).Article 

    Google Scholar 
    Gatti, A. B., Ferreira, A. G., Arduin, M. & Perez, S. C. G. D. A. Allelopathic effects of aqueous extracts of Artistolochia esperanzae O.Kuntze on development of Sesamum indicum L. seedlings. Acta Bot. Bras. 24(2), 454–461 (2010).Article 

    Google Scholar 
    Hou, Y. P. et al. Effects of litter from dominant tree species on seed germination and seedling growth of exotic plant Rhus typhina in hilly areas in Shandong peninsula. Sci. Silvae Sin. 52(6), 28–34 (2016) (In Chinese with English abstract).
    Google Scholar 
    Jiang, Z. et al. Effects of root exudates from Picea asperata seedlings on the seed germination and seedling growth of two herb species. Sci. Silvae Sin. 55(6), 160–166 (2019) (In Chinese with English abstract).
    Google Scholar 
    Hagan, D. L., Jose, S. & Lin, C. Allelopathic exudates of cogongrass (Imperata cylindrical): Implications for the performance of native pine savanna plant species in the Southeastern US. J. Chem. Ecol. 39, 312–322 (2013).CAS 
    PubMed 
    Article 

    Google Scholar 
    Cheng, F. & Cheng, Z. Research progress on the use of plant allelopathy in agriculture and the physiological and ecological mechanisms of allelopathy. Front. Plant Sci. 6, 1020 (2015).PubMed 
    PubMed Central 

    Google Scholar 
    Bogatek, R., Gniazdowska, A., Zakrzewska, W., Oracz, K. & Gawronski, S. W. Allelopathic effects of sunflower extracts on mustard seed germination and seedling growth. Biol. Plantarum 50(1), 156–158 (2006).Article 

    Google Scholar 
    Politycka, B. Peroxidase activity and lipid peroxidation in roots of cucumber seedlings influenced by derivatives of cinnamic and benzoic acids. Acta Physiol. Plant. 18(4), 365–370 (1996).CAS 

    Google Scholar 
    Williamson, G. B. & Richardson, D. Bioassays for allelopathy: Measuring treatment responses with independent controls. J. Chem. Ecol. 14(1), 181–187 (1988).Article 

    Google Scholar  More

  • in

    Impacts of climate change on reproductive phenology in tropical rainforests of Southeast Asia

    Data collection of flowering and fruiting phenologyMonthly reproductive phenology data recorded over 35 years (from April 1976 to September 2010) were collected from the Bulletin Fenologi Biji Benih dan Anak Benih (Bulletin of Seed and Seedling Phenology), which was deposited at the FRIM library. The bulletin reported seed and seedling availabilities and the flowering and fruiting phenology of trees at several research stations in Malaysia. The present study collected flowering and fruiting records of trees grown in FRIM arboretums located approximately 12 km northwest of Kuala Lumpur, Malaysia (latitude 3°24 ‘N, longitude 101°63 ‘E, elevation 80 m). There are both dipterocarp and non-dipterocarp arboretums in FRIM, both of which were founded in 1929. These arboretums preserve and maintain living trees for research and other purposes. Each month, three research staff members of FRIM with sufficient phenology monitoring training made observations with binoculars to record the presence of flowers and fruits on trees of each species on the forest floor from April 1976 to September 2010. The phenological status of the trees was recorded as flowering during the developmental stages from flower budding to blooming and as fruiting during the developmental stages from the occurrence of immature fruit to fruit ripening. Because only one or two individuals per species are grown at the FRIM arboretums, the flowering and fruiting phenology were monitored using these individuals. The resultant flowering and fruiting phenology data included a time series of binary data (1 for presence and 0 for absence) with a length of 417 months.The original data included 112 dipterocarp and 240 non-dipterocarp species. We excluded 17 dipterocarps and 125 non-dipterocarp species based on the following five criteria for data accuracy.

    1.

    Percentage of missing values is ≤50%: If the monthly flowering or fruiting phenology data of a species included a substantially large number of missing values ( >50%), the species was excluded.

    2.

    Stable flowering period: We considered an observation to be unreliable if the flowering period was significantly different among flowering events (if the coefficient of variation in the flowering period was larger or equal to 1.0).

    3.

    Flowering period is shorter than or equal to 12 months: we considered an observation to be unreliable if the flowering period was longer than 12 months because it was unlikely that the same tree would flower continuously for longer than 1 year.

    4.

    The flowering and fruiting frequencies were not significantly different between the first and second half of the census period: when the flowering frequency was zero for the first half of the observation period but was larger than 0.1 for the second half of the observation period, or when the flowering frequency was zero for the second half of the observation period but was larger than 0.1 for the first half of the observation period, we removed these species because data are not reliable (e.g., physiological conditions may have changed significantly). We adopted the same criteria for the fruiting phenology data.

    5.

    We removed overlapping species, herb species, and specimens with unknown species names.

    After removing unreliable species based on the five criteria explained above, we obtained 95 dipterocarp and 115 non-dipterocarp species (Supplementary Data 1). We used these species for further analyses. It is unlikely that our final data includes trees that were replaced by young trees during the census period because newly planted seedlings do not flower over 20–30 years until they are fully grown to the reproductive stage ( >20–30 cm DBH)45.Detection of seasonality in reproductive phenologyTo compare the flowering and fruiting phenology seasonality among different families, nine families that included at least five species were used. The number of flowering or fruiting events was counted for each month from January to December during a census, and then the frequency distribution was drawn as a histogram. Similarly, we also generated a histogram for the seed dispersal month, which was calculated as the month when fruiting ended (i.e., when the binary fruiting phenology data changed from one to zero).Classification of phenological patternsTo classify the phenological patterns, we performed time-series clustering using the R package TSclust46 with the hierarchical clustering method based on the Dynamic Time Warping distance of the flowering phenology data of each species. For this analysis, time points at which there were missing values for at least one species were excluded. Because of the large number of missing values in non-Dipterocarpaceae species, we performed time-series clustering only for the Dipterocarpaceae species based on 394 time points in total. The number of phenological clusters was estimated based on AIC, as explained below.Climate dataDaily minimum, mean, and maximum temperatures and precipitation data monitored at the FRIM KEPONG (3° 14’ N, 101° 42’ E, elevation 97 m) weather station were provided by the Malaysian Meteorological Department. We used the daily minimum temperature for our analysis because there were fewer missing values compared to the numbers of missing daily mean and daily maximum temperature values. The periods in which climate data were available were from 1 March 1973 to 31 March 1996, and from 23 July 1997 to 20 April 2005. We removed periods in which there were missing values spanning longer than 5 days. When the range of missing values spanned a period shorter than 3 days, we approximated these missing values using the mean minimum temperatures recorded on the adjacent three days. Although solar radiation data were not available for our study, the use of precipitation is sufficient for model fitting because there is a significant negative correlation between solar radiation and precipitation in Southeast Asia47.Climate data generated by GCMsAs the future climate inputs, we used bias-corrected climate input data from 1 January 2050 to 31 December 2099, with a daily temporal resolution and a 0.5° spatial resolution, provided by the ISI-MIP project48; these data are based on the Coupled Model Intercomparison Project Phase 5 outputs from three GCMs: GFDL–ESM2M, IPSL–CM5A-LR, and MIROC5. To compare the flowering phenology between 1976–1996 and 2050–2099, bias-corrected GCM data from 1 May 1976 to 31 March 1996, were also used. This period (1 May 1976–31 March 1996) is consistent with the period used for model fitting. We selected daily minimum temperature and precipitation time series from the 0.5° grid cells corresponding to the study site for phenology monitoring at FRIM. To compare flowering phenology among regions, we also used the same set of data from three other regions in Southeast Asia: Trang Province in Thailand (7° 4’ N, 99° 47’ E), Lambir Hills National Park in Malaysia (4° 2’ N, 113° 50’ E), and central Kalimantan in Indonesia (0° 06’ S, 114° 0’ E). Because the study site in FRIM was not in the center of a 0.5° grid cell, we interpolated the data using four grid cells in the vicinity of the observation site. We used the weighted average according to the distance between each observation site and the center of each corresponding grid cell.Although the climate input data provided by ISI-MIP were already bias-corrected, we conducted additional bias correction at FRIM using a historical scenario for each GCM data set and the observed weather data from 1 January 1976 to 31 December 2004 based on previously presented protocol49. We did not implement any bias correction for the frequency of dry days or precipitation intensity of wet days49 because we only focused on the average precipitation.The variances in the annual fluctuation of the monthly mean precipitation were not the same between the observation data and historical GCM runs at FRIM. For all three GCMs (GFDL–ESM2M, IPSL–CM5A-LR, and MIROC5), the variances in the yearly fluctuation output by the GCMs tended to be larger than that of the observed data at the FRIM KEPONG weather station during winter and spring. On the other hand, during summer and fall, the variances output by the GCMs tended to be smaller than that of the observed data. These biases could not be corrected using the previous method49. Therefore, we conducted the following bias correction for these data:$${p}_{i,m,y}^{{{{{{rm{GCM}}}}}}* }={r}_{i,m,y}^{{{{{{rm{GCM}}}}}}}cdot left[{F}_{Gamma }^{-1}left({F}_{Gamma }left({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}|{k}_{m,y},{theta }_{m,y}right)|{k}_{m,y}^{* },{theta }_{m,y}^{* }right)cdot {rho }_{m,y}^{{{{{{rm{GCM}}}}}}}right],$$
    (1)
    where ({p}_{i,m,y}^{{{{{{rm{GCM}}}}}}* }) is the bias-corrected precipitation value of the target GCM at year y, month m, and date i. In the equation, ({r}_{i,m,y}^{{{{{{rm{GCM}}}}}}}) is the ratio of the precipitation value of the GCM relative to the monthly mean value. Then, the following equation is used:$${r}_{i,m,y}^{{{{{{rm{GCM}}}}}}}=frac{{p}_{i,m,y}^{{{{{{rm{GCM}}}}}}}}{{bar{p}}_{m,y}^{{{{{{rm{GCM}}}}}}}},$$
    (2)
    where ({p}_{i,m,y}^{{{{{{rm{GCM}}}}}}}) is the precipitation value (not bias-corrected) of the GCM at year (y), month (m), and date i and ({bar{p}}_{m,y}^{{{{{{rm{GCM}}}}}}}) is the monthly mean precipitation value of the GCM at year (y) and month (m). In Eq. 1, ({F}_{Gamma }) represents the cumulative distribution function of a gamma distribution, ({F}_{Gamma }^{-1}) represents the inverse function of the cumulative distribution function of the gamma distribution, and ({k}_{m,y}) and ({theta }_{m,y}) are the shape parameters. In Eq. 1, ({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}) indicates the deviation of the monthly mean from the normal climate value of the corresponding period, and this value is calculated as follows:$${delta }_{m,y}^{{{{{{rm{GCM}}}}}}}=frac{{bar{p}}_{m,y}^{{{{{{rm{GCM}}}}}}}}{{rho }_{m,y}^{{{{{{rm{GCM}}}}}}}},$$
    (3)
    where ({rho }_{m,y}^{{{{{{rm{GCM}}}}}}}) is the normal climate value during the target period. In this method, we defined the normal climate value as the mean of the monthly mean precipitation values over 31 years.$${rho }_{m,y}^{{{{{{rm{GCM}}}}}}}=frac{1}{31}mathop{sum }limits_{j=y-15}^{y+15}{bar{p}}_{m,j}^{{{{{{rm{GCM}}}}}}}.$$
    (4)
    When the mean of a gamma distribution is fixed at one, the shape parameters are represented as follows:$${k}_{m,y}=frac{1}{Vleft({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}right)},$$
    (5)
    $${theta }_{m,y}=frac{1}{{k}_{m,y}},$$
    (6)
    where (Vleft({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}right)) indicates the variance in ({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}) at month (m) over 31 years.In this method, we assumed that the ({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}) value follows a gamma distribution and that the ratio of the variance of ({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}) to the variance of ({delta }_{m,y}^{{{{{{rm{obs}}}}}}}) is maintained even in the future scenario. Here, ({delta }_{m,y}^{{{{{{rm{obs}}}}}}}) represents the deviation of the monthly mean in the observation data from the normal climate value.$${delta }_{m,y}^{{{{{{rm{obs}}}}}}}=frac{{bar{p}}_{m,y}^{{{{{{rm{obs}}}}}}}}{{rho }_{m}^{{{{{{rm{obs}}}}}}}},$$
    (7)
    $${rho }_{m}^{{{{{{rm{obs}}}}}}}=frac{1}{28}mathop{sum }limits_{j=1976}^{2004}{bar{p}}_{m,y}^{{{{{{rm{obs}}}}}}}.$$
    (8)
    In the above equations, ({bar{p}}_{m,y}^{{{{{{rm{obs}}}}}}}) indicates the monthly mean precipitation value in the observed data. As mentioned above, because we assume that the ratio of the variance in ({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}) to the variance in ({delta }_{m,y}^{{{{{{rm{obs}}}}}}}) is maintained, ({k}_{m,y}^{* }) and ({theta }_{m,y}^{* }) are calculated as follows:$${k}_{m,y}^{* }=frac{{k}_{m,y}}{alpha },$$
    (9)
    $${theta }_{m,y}^{* }=frac{1}{{k}_{m,y}^{* }},$$
    (10)
    where$$alpha =frac{Vleft({delta }_{m,y}^{{{{{{{rm{GCM}}}}}}}^{{{{{{rm{h}}}}}}}}right)}{Vleft({delta }_{m,y}^{{{{{{rm{obs}}}}}}}right)}.$$
    (11)
    In Eq. 11, ({delta }_{m,y}^{{{{{{{rm{GCM}}}}}}}^{{{{{{rm{h}}}}}}}}) is the deviation of the monthly mean of the historical GCM precipitation data from the normal climate value. Here, we defined the normal climate value as the average monthly mean during 1976–2004.The method proposed here is an original bias correction method, but the above equations are easily derived if we assume that the ({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}) value follows a gamma distribution and that the ratio of the variance in ({delta }_{m,y}^{{{{{{rm{GCM}}}}}}}) to the variance in ({delta }_{m,y}^{{{{{{rm{obs}}}}}}}) is maintained even in the future scenario. Notably, because we combined this method with the bias correction method described previously49, Eq. 2 should be expressed as follows:$${r}_{i,m,y}^{{{{{{rm{GCM}}}}}}}=frac{{widetilde{p}}_{l,m,y}^{{{{{{rm{GCM}}}}}}}}{{bar{p}}_{m,y}^{{{{{{rm{GCM}}}}}}}},$$
    (12)
    where ({widetilde{p}}_{l,m,y}^{{{{{{rm{GCM}}}}}}}) is the precipitation data that are bias-corrected using the method described previously49. Bias-corrected data were compared with the data without bias correction (Supplementary Figs. 8–11).Statistical analyses and reproducibilityWe adopted previously presented models in which environmental triggers for floral induction accumulate for n1 days prior to the onset of floral induction21 (Supplementary Fig. 2). Flowers then develop for n2 days before opening (Supplementary Fig. 2). The model assumption of the time lag between floral induction and anthesis, which is denoted as n2, was validated by a previous finding in which the expression peaks of flowering-time genes, which are used as molecular markers of floral induction, were shown to occur at least one month before anthesis in Shorea curtisii19. S. curtissi is included in our data set. The CU at time t, ({{{{{rm{CU}}}}}}left(t|{theta }^{C}right)), is calculated as follows:$${{{{{rm{CU}}}}}}left(t|{theta }^{C}right)=mathop{sum }limits_{n={n}_{2}}^{{n}_{2}+{n}_{1}-1}{{{{{rm{max }}}}}}{bar{C}-xleft(t-nright),0},$$
    (13)
    where ({theta }^{C}=left{{n}_{1},{n}_{2},bar{C}right}) is the set of parameters and x(t) is the temperature at time t. Here, (bar{C}) indicates the threshold temperature. The term max{x1, x2} is a function that returns a larger value for the two arguments. Similarly, given ({theta }^{D}={{n}_{1},{n}_{2},bar{D}},) the DU at time t, ({{{{{rm{DU}}}}}}left(t|{theta }^{D}right)), is defined as the difference between the mean daily accumulation of rainfall over n1 days and a threshold rainfall level ((bar{D})):$${{{{{rm{DU}}}}}}left(t|{theta }^{D}right)={{{{{rm{max }}}}}}left{bar{D}-mathop{sum }limits_{n={n}_{2}}^{{n}_{2}+{n}_{1}-1}yleft(t-nright)/{n}_{1},0right},$$
    (14)
    where y(t) is the rainfall value at time t. The term max{x1, x2} is defined similarly as in Eq. 13.Logistic regression was performed using only the DU and using the product of CU and DU (CU × DU) as the explanatory variables and using the presence or absence of a first flowering event as the dependent variable for each phenological cluster. Because the number of phenological clusters is unknown, we performed forward selection on the cluster number based on the AIC. Let m be the number of phenological clusters based on the dendrogram drawn from the time-series clustering explained above (Supplementary Fig. 5). Given m phenological clusters, let ({G}_{k}^{m}) be the kth set of clusters in which the DU model is adopted for model fitting. Here, ({G}_{k}^{m}) indicates the set of cluster IDs, and k ranges from 0 to m(m+1)/2. For example, when m = 2 (i.e., there are two clusters, clusters 1 and 2), there are four cluster sets, calculated as follows:$${G}_{0}^{m=2}={},{G}_{1}^{m=2}={1},{G}_{2}^{m=2}={2},{G}_{3}^{m=2}={1,2},$$
    (15)
    where the element in the bracket indicates the ID of the cluster in which the DU model is adopted for model fitting. When k = 0, the DU model is not used; instead, the CU × DU model is adopted for model fitting for both clusters 1 and 2. Let i be the ith element of the vector E, which is defined as follows:$${{{{{bf{E}}}}}}={{t}_{1}^{1},,{t}_{2}^{1},…,,,{t}_{n}^{1},,…,,,{t}_{1}^{m},,{t}_{2}^{m},…,,{t}_{n}^{m}},$$
    (16)
    where n is the length of the time-series data for each cluster. Notably, n = 223 is the same for all species and clusters. The term ({t}_{1}^{m}) in the above equation denotes the first time point of the time series of length n for the species included in cluster m. Given m and k, let ({p}^{(m,k)}(i)) be the flowering probability of element i of vector E. The term ({p}^{(m,k)}(i)) is expressed as follows:$${{log }}left[frac{{p}^{left(m,kright)}left(iright)}{1-{p}^{left(m,kright)}left(iright)}right]= mathop{sum }limits_{j=1}^{m}{alpha }_{m,j}cdot {Z}_{m,j}left(iright)+mathop{sum }limits_{jin {G}_{k}^{left(mright)}}^{m}{beta }_{m,j}cdot {Z}_{m,j}left(iright)cdot {{{{{{rm{DU}}}}}}}_{m,j}left(i|{theta }_{j}^{D}right)\ +mathop{sum }limits_{jnotin {G}_{k}^{left(mright)}}^{m}{beta }_{m,j}cdot {Z}_{m,j}left(iright)cdot {{{{{rm{CU}}}}}}left(i|{theta }_{j}^{C}right)times {{{{{{rm{DU}}}}}}}_{m,j}left(i|{theta }_{j}^{D}right),$$
    (17)
    where ({Z}_{m,j}(i)) is the dummy variable indicating a cluster for i; ({Z}_{m,j}(i)) equals 1 if the ith element of E belongs to the jth cluster, otherwise it is zero, and ({alpha }_{m,j}) and ({beta }_{m,j}) in Eq. (5) are regression coefficients for the jth cluster when the species are grouped into m clusters. We estimate the parameters and the number of clusters based on a finite number of observations. Given the number of clusters m, for each of m clusters, the parameters were estimated by maximizing the loglikelihood value calculated for all combinations of potential parameter values for ({n}_{1},{n}_{2},bar{C},) and (bar{D}) within the ranges of [1 (min), 50 (max)] for n1, [1,50] for n2, [19,25] for (bar{C}), and [1,9] for (bar{D}). We varied the days (n1 and n2) by integers, temperature ((bar{C})) by tenths of a degree C, and daily precipitation ((bar{D})) by tenths of a mm. Regression coefficients (({alpha }_{m,j}), ({beta }_{m,j})) for all j values under a given m value and associated likelihoods were determined using generalized linear models with binomial error structures.With the results of the parameter estimations, we determined the number of clusters in two steps. For the first step, for a given m, we obtained (hat{k}(m)) according to the following equation:$$hat{k}(m)={arg }mathop{{min }}limits_{k}{{{{{{rm{AIC}}}}}}{m,k(m)},,k(m),=,0,,…,{2}^{m}}.$$
    (18)
    For the second step, with the results of (hat{k}) obtained from the first step, we obtained the estimate of the number of clusters according to forward selection by searching for the (hat{m}) value that satisfies the following inequalities:$${{{{{rm{AIC}}}}}}(hat{m},,hat{k}(hat{m})), < ,{{{{{rm{AIC}}}}}}(hat{m}+1,,hat{k}(hat{m}+1))cap {{{{{rm{AIC}}}}}}(hat{m},,hat{k}(hat{m})), < ,{{{{{rm{AIC}}}}}}(hat{m}-1,,hat{k}(hat{m}-1)).$$ (19) For model fitting, the first flowering month was extracted from the flowering phenology data. When flowering lasted more than 1 month, the month after the first flowering month was replaced by a value of zero (absence of flowering). If the month before the first flowering month was a missing value, the first flowering month was treated as a missing value and was not used for further analyses. We assumed that phenology monitoring was performed on the first date of each month.Projections of 21st-century changes in flowering phenologyWe used two scenarios (RCP2.6 and RCP8.5) to forecast future reproductive phenology in dipterocarp species for each of the three GCMs (GFDL–ESM2M, IPSL–CM5A-LR, and MIROC5). We predicted the flowering probability per month for each phenological cluster during the periods from 1 May 1976–31 March 1996 and from 1 January 2050–31 December 2099 based on the best model (Supplementary Table 2). The predicted flowering probability during the 2050–2099 period was normalized to that during the 1976–1996 period for each climate scenario and for each of three GCMs. To compare the seasonal patterns between 1976–1996 and 2050–2099, the predicted flowering probability was averaged for each month from January to December and plotted for each month in Fig. 6. R version 3.6.3 was used for all analyses.Reporting summaryFurther information on research design is available in the Nature Research Reporting Summary linked to this article. More

  • in

    Eukaryogenesis and oxygen in Earth history

    Sagan, L. On the origin of mitosing cells. J. Theor. Biol. 14, 255–274 (1967).CAS 
    PubMed 
    Article 

    Google Scholar 
    Taylor, F. J. R. Implications and extensions of the serial endosymbiosis theory of the origin of eukaryotes. Taxon 23, 229–258 (1974).Article 

    Google Scholar 
    Margulis, L. Serial endosymbiotic theory (SET) and composite individuality. Microbiol. Today 31, 172–175 (2004).
    Google Scholar 
    Mereschkowsky, C. Über Natur und Ursprung der Chromatophoren im Pflanzenreiche. Biol. Centralbl. 25, 593–604 (1905).
    Google Scholar 
    Wallin, I. E. On the nature of mitochondria. IX. Demonstration of the bacterial nature of mitochondria. Am. J. Anat. 36, 131–149 (1925).Article 

    Google Scholar 
    Martin, W. F. Physiology, anaerobes, and the origin of mitosing cells 50 years on. J. Theor. Biol. 434, 2–10 (2017).CAS 
    PubMed 
    Article 

    Google Scholar 
    Müller, M. et al. Biochemistry and evolution of anaerobic energy metabolism in eukaryotes. Microbiol. Mol. Biol. Rev. 76, 444–495 (2012).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Spang, A. et al. Complex archaea that bridge the gap between prokaryotes and eukaryotes. Nature 521, 173–179 (2015).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Imachi, H. et al. Isolation of an archaeon at the prokaryote–eukaryote interface. Nature 577, 519–525 (2020).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Morris, B. E. L., Henneberger, R., Huber, H. & Moissl-Eichinger, C. Microbial syntrophy: interaction for the common good. FEMS Microbiol. Rev. 37, 384–406 (2013).CAS 
    PubMed 
    Article 

    Google Scholar 
    Martin, W. & Müller, M. The hydrogen hypothesis for the first eukaryote. Nature 392, 37–41 (1998).CAS 
    PubMed 
    Article 

    Google Scholar 
    Moreira, D. & Lopez-Garcia, P. Symbiosis between methanogenic archaea and delta-proteobacteria as the origin of eukaryotes: the syntrophic hypothesis. J. Mol. Evol. 47, 517–530 (1998).CAS 
    PubMed 
    Article 

    Google Scholar 
    Sousa, F. L., Neukirchen, S., Allen, J. F., Lane, N. & Martin, W. F. Lokiarchaeon is hydrogen dependent. Nat. Microbiol. 1, 16034 (2016).CAS 
    PubMed 
    Article 

    Google Scholar 
    Spang, A. et al. Proposal of the reverse flow model for the origin of the eukaryotic cell based on comparative analyses of Asgard archaeal metabolism. Nat. Microbiol. 4, 1138–1148 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    López-García, P. & Moreira, D. The syntrophy hypothesis for the origin of eukaryotes revisited. Nat. Microbiol. 5, 655–667 (2020).PubMed 
    Article 
    CAS 

    Google Scholar 
    Eme, L., Sharpe, S. C., Brown, M. W. & Roger, A. J. in The Origin and Evolution of Eukaryotes (eds. Keeling, P. J. & Koonin, E. V.) 165–180 (Cold Spring Harbor Perspectives in Biology, 2014).Betts, H. C. et al. Integrated genomic and fossil evidence illuminates life’s early evolution and eukaryote origin. Nat. Ecol. Evol. 2, 1556–1562 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Porter, S. M. Insights into eukaryogenesis from the fossil record. Interface Focus 10, 20190105 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Agić, H. in Prebiotic Chemistry and the Origin of Life (eds. Neubeck, A. & McMahon, S.) 255–289 (Springer International, 2021).Lyons, T. W., Reinhard, C. T. & Planavsky, N. J. The rise of oxygen in Earth’s early ocean and atmosphere. Nature 506, 307–315 (2014).CAS 
    PubMed 
    Article 

    Google Scholar 
    Lenton, T. M. & Daines, S. J. Biogeochemical transformations in the history of the ocean. Ann. Rev. Mar. Sci. 9, 31–58 (2017).PubMed 
    Article 

    Google Scholar 
    Lenton, T. M. On the use of models in understanding the rise of complex life. Interface Focus 10, 20200018 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Liu, P. et al. Triple oxygen isotope constraints on atmospheric O2 and biological productivity during the mid-Proterozoic. Proc. Natl Acad. Sci. USA 118, e2105074118 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Mentel, M. & Martin, W. Energy metabolism among eukaryotic anaerobes in light of Proterozoic ocean chemistry. Philos. Trans. R. Soc. Lond. B 363, 2717–2729 (2008).Article 

    Google Scholar 
    Zimorski, V., Mentel, M., Tielens, A. G. M. & Martin, W. F. Energy metabolism in anaerobic eukaryotes and Earth’s late oxygenation. Free Radic. Biol. Med. 140, 279–294 (2019).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Martin, W. F., Tielens, A. G. M. & Mentel, M. Mitochondria and Anaerobic Energy Metabolism in Eukaryotes: Biochemistry and Evolution (Walter de Gruyter, 2020).Hall, J. B. The nature of the host in the origin of the eukaryote cell. J. Theor. Biol. 38, 413–418 (1973).CAS 
    PubMed 
    Article 

    Google Scholar 
    Stanier, R. Y. in Organization and Control in Prokaryotic and Eukaryotic Cells (eds. Charles, H. P. & Knight, B. C. J. G.) vol. 20, 1–38 (Cambridge Univ. Press, 1970).De Duve, C. Origin of mitochondria. Science 182, 85 (1973).PubMed 
    Article 

    Google Scholar 
    Andersson, S. G. & Kurland, C. G. Origins of mitochondria and hydrogenosomes. Curr. Opin. Microbiol. 2, 535–541 (1999).CAS 
    PubMed 
    Article 

    Google Scholar 
    Cavalier-Smith, T. The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa. Int. J. Syst. Evol. Microbiol. 52, 297–354 (2002).CAS 
    PubMed 
    Article 

    Google Scholar 
    de Duve, C. The origin of eukaryotes: a reappraisal. Nat. Rev. Genet. 8, 395–403 (2007).PubMed 
    Article 
    CAS 

    Google Scholar 
    Knoll, A. H. & Nowak, M. A. The timetable of evolution. Sci. Adv. 3, e1603076 (2017).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Martin, W. F. & Müller, M. Origin of Mitochondria and Hydrogenosomes (Springer, 2007).Lindmark, D. G. & Müller, M. Hydrogenosome, a cytoplasmic organelle of the anaerobic flagellate Tritrichomonas foetus, and its role in pyruvate metabolism. J. Biol. Chem. 248, 7724–7728 (1973).CAS 
    PubMed 
    Article 

    Google Scholar 
    Müller, M. in Origin of Mitochondria and Hydrogenosomes (eds. Martin, W. F. & Müller, M.) 1–10 (Springer, 2007).Zillig, W. et al. Did eukaryotes originate by a fusion event? Endocytobiosis Cell Res. 6, 1–25 (1989).
    Google Scholar 
    Embley, T. M. & Martin, W. Eukaryotic evolution, changes and challenges. Nature 440, 623–630 (2006).CAS 
    PubMed 
    Article 

    Google Scholar 
    Stairs, C. W., Leger, M. M. & Roger, A. J. Diversity and origins of anaerobic metabolism in mitochondria and related organelles. Philos. Trans. R. Soc. Lond. B 370, 20140326 (2015).Article 
    CAS 

    Google Scholar 
    Roger, A. J., Muñoz-Gómez, S. A. & Kamikawa, R. The origin and diversification of mitochondria. Curr. Biol. 27, R1177–R1192 (2017).CAS 
    PubMed 
    Article 

    Google Scholar 
    Zachar, I. & Szathmáry, E. Breath-giving cooperation: critical review of origin of mitochondria hypotheses. Biol. Direct 12, 19 (2017).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Eme, L., Spang, A., Lombard, J., Stairs, C. W. & Ettema, T. J. G. Archaea and the origin of eukaryotes. Nat. Rev. Microbiol. 15, 711–723 (2018).Article 
    CAS 

    Google Scholar 
    Stairs, C. W. et al. Microbial eukaryotes have adapted to hypoxia by horizontal acquisitions of a gene involved in rhodoquinone biosynthesis. eLife 7, e34292 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Martin, W. F. Too much eukaryote LGT. Bioessays 39, 1700115 (2017).Article 

    Google Scholar 
    Leger, M. M., Eme, L., Stairs, C. W. & Roger, A. J. Demystifying eukaryote lateral gene transfer (response to Martin 2017 https://doi.org/10.1002/bies.201700115). Bioessays 40, e1700242 (2018).Martin, W. Mosaic bacterial chromosomes: a challenge en route to a tree of genomes. Bioessays 21, 99–104 (1999).CAS 
    PubMed 
    Article 

    Google Scholar 
    Nagies, F. S. P., Brueckner, J., Tria, F. D. K. & Martin, W. F. A spectrum of verticality across genes. PLoS Genet. 16, e1009200 (2020).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Guy, L. & Ettema, T. J. G. The archaeal ‘TACK’ superphylum and the origin of eukaryotes. Trends Microbiol. 19, 580–587 (2011).CAS 
    PubMed 
    Article 

    Google Scholar 
    Williams, T. A., Foster, P. G., Cox, C. J. & Embley, T. M. An archaeal origin of eukaryotes supports only two primary domains of life. Nature 504, 231–236 (2013).CAS 
    PubMed 
    Article 

    Google Scholar 
    McInerney, J. O., O’Connell, M. J. & Pisani, D. The hybrid nature of the Eukaryota and a consilient view of life on Earth. Nat. Rev. Microbiol. 12, 449–455 (2014).CAS 
    PubMed 
    Article 

    Google Scholar 
    Raymann, K., Brochier-Armanet, C. & Gribaldo, S. The two-domain tree of life is linked to a new root for the Archaea. Proc. Natl Acad. Sci. USA 112, 6670–6675 (2015).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Williams, T. A., Cox, C. J., Foster, P. G., Szöllősi, G. J. & Embley, T. M. Phylogenomics provides robust support for a two-domains tree of life. Nat. Ecol. Evol. 4, 138–147 (2020).PubMed 
    Article 

    Google Scholar 
    Zaremba-Niedzwiedzka, K. et al. Asgard archaea illuminate the origin of eukaryotic cellular complexity. Nature 541, 353–358 (2017).CAS 
    PubMed 
    Article 

    Google Scholar 
    López-García, P. & Moreira, D. Cultured Asgard archaea shed light on eukaryogenesis. Cell 181, 232–235 (2020).PubMed 
    Article 
    CAS 

    Google Scholar 
    Martin, W. F., Tielens, A. G. M., Mentel, M., Garg, S. G. & Gould, S. B. The physiology of phagocytosis in the context of mitochondrial origin. Microbiol. Mol. Biol. Rev. 81, e00008–17 (2017).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Berkner, L. V. & Marshall, L. C. History of major atmospheric components. Proc. Natl Acad. Sci. USA 53, 1215–1226 (1965).CAS 
    PubMed Central 
    Article 

    Google Scholar 
    Stolper, D. A., Revsbech, N. P. & Canfield, D. E. Aerobic growth at nanomolar oxygen concentrations. Proc. Natl Acad. Sci. USA 107, 18755–18760 (2010).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Degli Esposti, M., Mentel, M., Martin, W. & Sousa, F. L. Oxygen reductases in alphaproteobacterial genomes: physiological evolution from low to high oxygen environments. Front. Microbiol. 10, 499 (2019).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Berg, J. et al. How low can they go? Aerobic respiration by microorganisms under apparent anoxia. FEMS Microbiol. Rev. https://doi.org/10.1093/femsre/fuac006 (2022).Cloud, P. Cosmos, Earth, and Man: A Short History of the Universe (Yale Univ. Press, 1978).Pichler, H. & Riezman, H. Where sterols are required for endocytosis. Biochim. Biophys. Acta 1666, 51–61 (2004).CAS 
    PubMed 
    Article 

    Google Scholar 
    Hoshino, Y. & Gaucher, E. A. Evolution of bacterial steroid biosynthesis and its impact on eukaryogenesis. Proc. Natl Acad. Sci. USA 118, e2101276118 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Waldbauer, J. R., Newman, D. K. & Summons, R. E. Microaerobic steroid biosynthesis and the molecular fossil record of Archean life. Proc. Natl Acad. Sci. USA 108, 13409–13414 (2011).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Valentine, D. L. in Symbiosis: Mechanisms and Model Systems (ed. Seckbach, J.) 147–161 (Springer, 2002).Canfield, D. E. & Thamdrup, B. Towards a consistent classification scheme for geochemical environments, or, why we wish the term ‘suboxic’ would go away. Geobiology 7, 385–392 (2009).CAS 
    PubMed 
    Article 

    Google Scholar 
    McInerney, M. J., Sieber, J. R. & Gunsalus, R. P. Syntrophy in anaerobic global carbon cycles. Curr. Opin. Biotechnol. 20, 623–632 (2009).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Schink, B. Synergistic interactions in the microbial world. Antonie Van Leeuwenhoek 81, 257–261 (2002).CAS 
    PubMed 
    Article 

    Google Scholar 
    Stams, A. J. M. & Plugge, C. M. Electron transfer in syntrophic communities of anaerobic bacteria and archaea. Nat. Rev. Microbiol. 7, 568–577 (2009).CAS 
    PubMed 
    Article 

    Google Scholar 
    Embley, T. M., van der Giezen, M., Horner, D. S., Dyal, P. L. & Foster, P. Mitochondria and hydrogenosomes are two forms of the same fundamental organelle. Philos. Trans. R. Soc. Lond. B 358, 191–201 (2003). discussion 201–2.CAS 
    Article 

    Google Scholar 
    Donoghue, P. C. J. & Purnell, M. A. Distinguishing heat from light in debate over controversial fossils. Bioessays 31, 178–189 (2009).PubMed 
    Article 

    Google Scholar 
    Brocks, J. J., Logan, G. A., Buick, R. & Summons, R. E. Archean molecular fossils and the early rise of eukaryotes. Science 285, 1033–1036 (1999).CAS 
    PubMed 
    Article 

    Google Scholar 
    Rasmussen, B., Fletcher, I. R., Brocks, J. J. & Kilburn, M. R. Reassessing the first appearance of eukaryotes and cyanobacteria. Nature 455, 1101–1104 (2008).CAS 
    PubMed 
    Article 

    Google Scholar 
    French, K. L. et al. Reappraisal of hydrocarbon biomarkers in Archean rocks. Proc. Natl Acad. Sci. USA 112, 5915–5920 (2015).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Brocks, J. J. et al. The rise of algae in Cryogenian oceans and the emergence of animals. Nature 548, 578–581 (2017).CAS 
    PubMed 
    Article 

    Google Scholar 
    Hoshino, Y. et al. Cryogenian evolution of stigmasteroid biosynthesis. Sci. Adv. 3, e1700887 (2017).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Bengtson, S. et al. Fungus-like mycelial fossils in 2.4-billion-year-old vesicular basalt. Nat. Ecol. Evol. 1, 141 (2017).PubMed 
    Article 

    Google Scholar 
    Butterfield, N. J. Probable Proterozoic fungi. Paleobiology 31, 165–182 (2005).Article 

    Google Scholar 
    Butterfield, N. J. Early evolution of the Eukaryota. Palaeontology 58, 5–17 (2015).Article 

    Google Scholar 
    Berbee, M. L. et al. Genomic and fossil windows into the secret lives of the most ancient fungi. Nat. Rev. Microbiol. 18, 717–730 (2020).CAS 
    PubMed 
    Article 

    Google Scholar 
    Lamb, D. M., Awramik, S. M., Chapman, D. J. & Zhu, S. Evidence for eukaryotic diversification in the 1800 million-year-old Changzhougou Formation, North China. Precambrian Res. 173, 93–104 (2009).CAS 
    Article 

    Google Scholar 
    Javaux, E. J., Knoll, A. H. & Walter, M. R. Morphological and ecological complexity in early eukaryotic ecosystems. Nature 412, 66–69 (2001).CAS 
    PubMed 
    Article 

    Google Scholar 
    Butterfield, N. J. Modes of pre-Ediacaran multicellularity. Precambrian Res. 173, 201–211 (2009).CAS 
    Article 

    Google Scholar 
    Peng, Y., Bao, H. & Yuan, X. New morphological observations for Paleoproterozoic acritarchs from the Chuanlinggou Formation, North China. Precambrian Res. 168, 223–232 (2009).CAS 
    Article 

    Google Scholar 
    Javaux, E. J. in Origins and Evolution of Life: An Astrobiological Perspective (eds Gargaud, M., López-García, P. & Martin, H.) 414–449 (Cambridge Univ. Press, 2011).Stairs, C. W. & Ettema, T. J. G. The archaeal roots of the eukaryotic dynamic actin cytoskeleton. Curr. Biol. 30, R521–R526 (2020).CAS 
    PubMed 
    Article 

    Google Scholar 
    Carlisle, E. M., Jobbins, M., Pankhania, V., Cunningham, J. A. & Donoghue, P. C. J. Experimental taphonomy of organelles and the fossil record of early eukaryote evolution. Sci. Adv. 7, eabe9487 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Han, T. M. & Runnegar, B. Megascopic eukaryotic algae from the 2.1-billion-year-old negaunee iron-formation, Michigan. Science 257, 232–235 (1992).CAS 
    PubMed 
    Article 

    Google Scholar 
    Javaux, E. J. & Lepot, K. The Paleoproterozoic fossil record: implications for the evolution of the biosphere during Earth’s middle-age. Earth-Sci. Rev. 176, 68–86 (2018).CAS 
    Article 

    Google Scholar 
    Agić, H., Moczydłowska, M. & Yin, L. Diversity of organic-walled microfossils from the early Mesoproterozoic Ruyang Group, North China Craton – A window into the early eukaryote evolution. Precambrian Res. 297, 101–130 (2017).Article 
    CAS 

    Google Scholar 
    Pang, K. et al. The nature and origin of nucleus-like intracellular inclusions in Paleoproterozoic eukaryote microfossils. Geobiology 11, 499–510 (2013).CAS 
    PubMed 

    Google Scholar 
    Bengtson, S., Belivanova, V., Rasmussen, B. & Whitehouse, M. The controversial ‘Cambrian’ fossils of the Vindhyan are real but more than a billion years older. Proc. Natl Acad. Sci. USA 106, 7729–7734 (2009).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Bengtson, S., Sallstedt, T., Belivanova, V. & Whitehouse, M. Three-dimensional preservation of cellular and subcellular structures suggests 1.6 billion-year-old crown-group red algae. PLoS Biol. 15, e2000735 (2017).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Tang, Q., Pang, K., Yuan, X. & Xiao, S. A one-billion-year-old multicellular chlorophyte. Nat. Ecol. Evol. 4, 543–549 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Bykova, N. et al. Seaweeds through time: morphological and ecological analysis of Proterozoic and early Paleozoic benthic macroalgae. Precambrian Res. 350, 105875 (2020).CAS 
    Article 

    Google Scholar 
    Maloney, K. M. et al. New multicellular marine macroalgae from the early Tonian of northwestern Canada. Geology 49, 743–747 (2021).CAS 
    Article 

    Google Scholar 
    Tang, Q. et al. The Proterozoic macrofossil Tawuia as a coenocytic eukaryote and a possible macroalga. Palaeogeogr. Palaeoclimatol. Palaeoecol. 576, 110485 (2021).Article 

    Google Scholar 
    Sforna, M. C. et al. Intracellular bound chlorophyll residues identify 1 Gyr-old fossils as eukaryotic algae. Nat. Commun. 13, 146 (2022).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Strother, P. K. et al. A possible billion-year-old holozoan with differentiated multicellularity. Curr. Biol. 31, 2658–2665.e2 (2021).CAS 
    PubMed 
    Article 

    Google Scholar 
    Loron, C. C. et al. Early fungi from the Proterozoic era in Arctic Canada. Nature 570, 232–235 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Bonneville, S. et al. Molecular identification of fungi microfossils in a Neoproterozoic shale rock. Sci. Adv. 6, eaax7599 (2020).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Gibson, T. M. et al. Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis. Geology 46, 135–138 (2018).CAS 
    Article 

    Google Scholar 
    Butterfield, N. J. Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes. Paleobiology 26, 386–404 (2000).Article 

    Google Scholar 
    Husson, J. M. & Peters, S. E. Nature of the sedimentary rock record and its implications for Earth system evolution. Emerg. Top. Life Sci. 2, 125–136 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Donoghue, P. C. J. & Yang, Z. The evolution of methods for establishing evolutionary timescales. Philos. Trans. R. Soc. Lond. B 371, 20160020 (2016).Article 

    Google Scholar 
    Berney, C. & Pawlowski, J. A molecular time-scale for eukaryote evolution recalibrated with the continuous microfossil record. Proc. Biol. Sci. 273, 1867–1872 (2006).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Chernikova, D., Motamedi, S., Csürös, M., Koonin, E. V. & Rogozin, I. B. A late origin of the extant eukaryotic diversity: divergence time estimates using rare genomic changes. Biol. Direct 6, 26 (2011).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Parfrey, L. W., Lahr, D. J. G., Knoll, A. H. & Katz, L. A. Estimating the timing of early eukaryotic diversification with multigene molecular clocks. Proc. Natl Acad. Sci. USA 108, 13624–13629 (2011).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Shih, P. M. & Matzke, N. J. Primary endosymbiosis events date to the later Proterozoic with cross-calibrated phylogenetic dating of duplicated ATPase proteins. Proc. Natl Acad. Sci. USA 110, 12355–12360 (2013).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Canfield, D. E. The early history of atmospheric oxygen: homage to Robert M. Garrels. Annu. Rev. Earth Planet. Sci. 33, 1–36 (2005).CAS 
    Article 

    Google Scholar 
    Kump, L. R. The rise of atmospheric oxygen. Nature 451, 277–278 (2008).CAS 
    PubMed 
    Article 

    Google Scholar 
    Holland, H. D. When did the Earth’s atmosphere become oxic? A reply. Geochem. N. 100, 20–22 (1999).
    Google Scholar 
    Holland, H. D. Volcanic gases, black smokers, and the great oxidation event. Geochim. Cosmochim. Acta 66, 3811–3826 (2002).CAS 
    Article 

    Google Scholar 
    Farquhar, J., Bao, H. & Thiemens, M. Atmospheric influence of Earth’s earliest sulfur cycle. Science 289, 756–759 (2000).CAS 
    PubMed 
    Article 

    Google Scholar 
    Poulton, S. W. et al. A 200-million-year delay in permanent atmospheric oxygenation. Nature 592, 232–236 (2021).CAS 
    PubMed 
    Article 

    Google Scholar 
    Hodgskiss, M. S. W. & Sperling, E. A. A prolonged, two-step oxygenation of Earth’s early atmosphere: support from confidence intervals. Geology https://doi.org/10.1130/g49385.1 (2021).Article 

    Google Scholar 
    Fischer, W. W., Hemp, J. & Johnson, J. E. Evolution of oxygenic photosynthesis. Annu. Rev. Earth Planet. Sci. 44, 647–683 (2016).CAS 
    Article 

    Google Scholar 
    Sánchez-Baracaldo, P. & Cardona, T. On the origin of oxygenic photosynthesis and Cyanobacteria. N. Phytol. 225, 1440–1446 (2020).Article 

    Google Scholar 
    Fournier, G. P. et al. The Archean origin of oxygenic photosynthesis and extant cyanobacterial lineages. Proc. Biol. Sci. 288, 20210675 (2021).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Cardona, T., Sánchez-Baracaldo, P., Rutherford, A. W. & Larkum, A. W. Early Archean origin of Photosystem II. Geobiology 17, 127–150 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Eigenbrode, J. L. & Freeman, K. H. Late Archean rise of aerobic microbial ecosystems. Proc. Natl Acad. Sci. USA 103, 15759–15764 (2006).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Daines, S. J. & Lenton, T. M. The effect of widespread early aerobic marine ecosystems on methane cycling and the Great Oxidation. Earth Planet. Sci. Lett. 434, 42–51 (2016).CAS 
    Article 

    Google Scholar 
    Crowe, S. A. et al. Atmospheric oxygenation three billion years ago. Nature 501, 535–538 (2013).CAS 
    PubMed 
    Article 

    Google Scholar 
    Planavsky, N. J. et al. Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event. Nat. Geosci. 7, 283–286 (2014).CAS 
    Article 

    Google Scholar 
    Daye, M. et al. Light-driven anaerobic microbial oxidation of manganese. Nature 576, 311–314 (2019).PubMed 
    Article 
    CAS 

    Google Scholar 
    Slotznick, S. P. et al. Reexamination of 2.5-Ga ‘whiff’ of oxygen interval points to anoxic ocean before GOE. Sci. Adv. 8, eabj7190 (2022).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Soo, R. M., Hemp, J., Parks, D. H., Fischer, W. W. & Hugenholtz, P. On the origins of oxygenic photosynthesis and aerobic respiration in Cyanobacteria. Science 355, 1436–1440 (2017).CAS 
    PubMed 
    Article 

    Google Scholar 
    Jabłońska, J. & Tawfik, D. S. The evolution of oxygen-utilizing enzymes suggests early biosphere oxygenation. Nat. Ecol. Evol. 5, 442–448 (2021).PubMed 
    Article 

    Google Scholar 
    Mentel, M., Röttger, M., Leys, S., Tielens, A. G. M. & Martin, W. F. Of early animals, anaerobic mitochondria, and a modern sponge. Bioessays 36, 924–932 (2014).PubMed 
    Article 

    Google Scholar 
    Lenton, T. M. et al. Earliest land plants created modern levels of atmospheric oxygen. Proc. Natl Acad. Sci. USA 113, 9704–9709 (2016).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Krause, A. J. et al. Stepwise oxygenation of the Paleozoic atmosphere. Nat. Commun. 9, 4081 (2018).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Daines, S. J., Mills, B. J. W. & Lenton, T. M. Atmospheric oxygen regulation at low Proterozoic levels by incomplete oxidative weathering of sedimentary organic carbon. Nat. Commun. 8, 14379 (2017).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Canfield, D. E. A new model for Proterozoic ocean chemistry. Nature 396, 450–453 (1998).CAS 
    Article 

    Google Scholar 
    Sperling, E. A. et al. Statistical analysis of iron geochemical data suggests limited late Proterozoic oxygenation. Nature 523, 451–454 (2015).CAS 
    PubMed 
    Article 

    Google Scholar 
    Planavsky, N. J. et al. Low mid-Proterozoic atmospheric oxygen levels and the delayed rise of animals. Science 346, 635–638 (2014).CAS 
    PubMed 
    Article 

    Google Scholar 
    Cole, D. B. et al. A shale-hosted Cr isotope record of low atmospheric oxygen during the Proterozoic. Geology 44, 555–558 (2016).CAS 
    Article 

    Google Scholar 
    Wang, C. et al. Strong evidence for a weakly oxygenated ocean-atmosphere system during the Proterozoic. Proc. Natl Acad. Sci. USA 119, e2116101119 (2022).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Reinhard, C. T., Planavsky, N. J., Olson, S. L., Lyons, T. W. & Erwin, D. H. Earth’s oxygen cycle and the evolution of animal life. Proc. Natl Acad. Sci. USA 113, 8933–8938 (2016).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Poulton, S. W. & Canfield, D. E. Ferruginous conditions: a dominant feature of the ocean through Earth’s history. Elements 7, 107–112 (2011).CAS 
    Article 

    Google Scholar 
    Gilleaudeau, G. J. et al. Uranium isotope evidence for limited euxinia in mid-Proterozoic oceans. Earth Planet. Sci. Lett. 521, 150–157 (2019).CAS 
    Article 

    Google Scholar 
    Cole, D. B. et al. On the co-evolution of surface oxygen levels and animals. Geobiology 319, 55 (2020).
    Google Scholar 
    Friese, A. et al. Organic matter mineralization in modern and ancient ferruginous sediments. Nat. Commun. 12, 2216 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Sperling, E. A., Knoll, A. H. & Girguis, P. R. The ecological physiology of Earth’s second oxygen revolution. Annu. Rev. Ecol. Evol. Syst. 46, 215–235 (2015).Article 

    Google Scholar 
    Knoll, A. H. Paleobiological perspectives on early eukaryotic evolution. Cold Spring Harb. Perspect. Biol. 6, a016121 (2014).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Cohen, P. A. & Kodner, R. B. The earliest history of eukaryotic life: uncovering an evolutionary story through the integration of biological and geological data. Trends Ecol. Evol. https://doi.org/10.1016/j.tree.2021.11.005 (2021).Szathmáry, E. & Smith, J. M. The major evolutionary transitions. Nature 374, 227–232 (1995).PubMed 
    Article 

    Google Scholar 
    Lane, N. & Martin, W. The energetics of genome complexity. Nature 467, 929–934 (2010).CAS 
    PubMed 
    Article 

    Google Scholar 
    Theissen, U., Hoffmeister, M., Grieshaber, M. & Martin, W. Single eubacterial origin of eukaryotic sulfide: quinone oxidoreductase, a mitochondrial enzyme conserved from the early evolution of eukaryotes during anoxic and sulfidic times. Mol. Biol. Evol. 20, 1564–1574 (2003).CAS 
    PubMed 
    Article 

    Google Scholar 
    Martin, W. et al. Early cell evolution, eukaryotes, anoxia, sulfide, oxygen, fungi first (?), and a tree of genomes revisited. IUBMB Life 55, 193–204 (2003).Gould, S. B. et al. Adaptation to life on land at high O2 via transition from ferredoxin-to NADH-dependent redox balance. Proc. Biol. Sci. 286, 20191491 (2019).CAS 
    PubMed 
    PubMed Central 

    Google Scholar 
    Mills, D. B. The origin of phagocytosis in Earth history. Interface Focus 10, 20200019 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Nguyen, K. et al. Absence of biomarker evidence for early eukaryotic life from the Mesoproterozoic Roper Group: searching across a marine redox gradient in mid-Proterozoic habitability. Geobiology 17, 247–260 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Lyons, T. W., Diamond, C. W., Planavsky, N. J., Reinhard, C. T. & Li, C. Oxygenation, life, and the planetary system during Earth’s middle history: an overview. Astrobiology 21, 906–923 (2021).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Gray, M. W. & Doolittle, W. F. Has the endosymbiont hypothesis been proven? Microbiol. Rev. 46, 1–42 (1982).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Gray, M. W., Burger, G. & Lang, B. F. Mitochondrial evolution. Science 283, 1476–1481 (1999).CAS 
    PubMed 
    Article 

    Google Scholar 
    Yang, D., Oyaizu, Y., Oyaizu, H., Olsen, G. J. & Woese, C. R. Mitochondrial origins. Proc. Natl Acad. Sci. USA 82, 4443–4447 (1985).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Woese, C. R. Bacterial evolution. Microbiol. Rev. 51, 221–271 (1987).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Martijn, J., Vosseberg, J., Guy, L., Offre, P. & Ettema, T. J. G. Deep mitochondrial origin outside the sampled alphaproteobacteria. Nature 557, 101–105 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Muñoz-Gómez, S. A. et al. Site-and-branch-heterogeneous analyses of an expanded dataset favour mitochondria as sister to known Alphaproteobacteria. Nat. Ecol. Evol. 6, 253–262 (2022).Fan, L. et al. Phylogenetic analyses with systematic taxon sampling show that mitochondria branch within Alphaproteobacteria. Nat. Ecol. Evol. 4, 1213–1219 (2020).PubMed 
    Article 

    Google Scholar 
    Richards, T. A. & van der Giezen, M. Evolution of the Isd11–IscS complex reveals a single α-proteobacterial endosymbiosis for all eukaryotes. Mol. Biol. Evol. 23, 1341–1344 (2006).CAS 
    PubMed 
    Article 

    Google Scholar 
    Sapp, J. in Origin of Mitochondria and Hydrogenosomes (eds. Martin, W. F. & Müller, M.) 57–83 (Springer, 2007).Poole, A. M. & Gribaldo, S. Eukaryotic origins: how and when was the mitochondrion acquired? Cold Spring Harb. Perspect. Biol. 6, a015990 (2014).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Cavalier-Smith, T. in Endocytobiology II (eds Schenk, H. E. A. & Schwemmler, W. S.) 1027–1034 (de Gruyter, 1983).Martijn, J. & Ettema, T. J. G. From archaeon to eukaryote: the evolutionary dark ages of the eukaryotic cell. Biochem. Soc. Trans. 41, 451–457 (2013).CAS 
    PubMed 
    Article 

    Google Scholar 
    Canfield, D. E. Oxygen: a Four Billion Year History (Princeton Univ. Press, 2014).Holland, H. D. in Petrologic Studies: a Volume in Honor of A. F. Buddington (eds Engel, A. E. J., James, H. L. & Leonard, B. F.) 447–477 (Geological Society of America, 1962).Cloud, P. E. Jr. Significance of the Gunflint (Precambrian) microflora: photosynthetic oxygen may have had important local effects before becoming a major atmospheric gas. Science 148, 27–35 (1965).PubMed 
    Article 

    Google Scholar 
    Rivera, M. C. & Lake, J. A. The ring of life provides evidence for a genome fusion origin of eukaryotes. Nature 431, 152–155 (2004).CAS 
    PubMed 
    Article 

    Google Scholar 
    Pisani, D., Cotton, J. A. & McInerney, J. O. Supertrees disentangle the chimerical origin of eukaryotic genomes. Mol. Biol. Evol. 24, 1752–1760 (2007).CAS 
    PubMed 
    Article 

    Google Scholar 
    Esser, C., Martin, W. & Dagan, T. The origin of mitochondria in light of a fluid prokaryotic chromosome model. Biol. Lett. 3, 180–184 (2007).CAS 
    PubMed 
    Article 

    Google Scholar  More

  • in

    Potential negative effects of ocean afforestation on offshore ecosystems

    Bach, L. T. et al. Testing the climate intervention potential of ocean afforestation using the Great Atlantic Sargassum Belt. Nat. Commun. 12, 2556 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    N‘Yeurt, A. D. R., Chynoweth, D. P., Capron, M. E., Stewart, J. R. & Hasan, M. A. Negative carbon via ocean afforestation. Process Saf. Environ. Prot. 90, 467–474 (2012).Article 
    CAS 

    Google Scholar 
    Duarte, C. M., Bruhn, A. & Krause-Jensen, D. A seaweed aquaculture imperative to meet global sustainability targets. Nat. Sustain. 5, 185–193 (2022).Article 

    Google Scholar 
    Woody, T. Seaweed ‘forests’ can help fight climate change. National Geographic https://www.nationalgeographic.co.uk/environment-and-conservation/2019/08/seaweed-forests-can-help-fight-climate-change (2019).Godin, M. The ocean farmers trying to save the world with seaweed. Time https://time.com/5848994/seaweed-climate-change-solution/ (2020).Marshall, M. Kelp is coming: how seaweed could prevent catastrophic climate change. New Scientist https://www.newscientist.com/article/mg24632821-100-kelp-is-coming-how-seaweed-could-prevent-catastrophic-climate-change/ (2020).Bever, F. ‘Run the oil industry in reverse’: fighting climate change by farming kelp. NPR https://www.npr.org/2021/03/01/970670565/run-the-oil-industry-in-reverse-fighting-climate-change-by-farming-kelp (2021).Running Tide. https://www.runningtide.com/ (2022).IPCC: Summary for Policymakers. In Global Warming of 1.5 °C (eds Masson-Delmotte, V. et al.) (WMO, 2018).IPCC: Summary for Policymakers. In Climate Change 2021: The Physical Science Basis (eds Masson-Delmotte, V. et al.) (Cambridge Univ. Press) (in the press).GESAMP. High Level Review of a Wide Range of Proposed Marine Geoengineering Techniques (eds Boyd, P. W. & Vivian, C. M. G.) GESAMP Working Group 41 (International Maritime Organization, 2019).Boyd, P. & Vivian, C. Should we fertilize oceans or seed clouds? No one knows. Nature 570, 155–157 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Law, C. S. Predicting and monitoring the impact of large-scale iron fertilisation on marine trace gas emissions. Mar. Ecol. Prog. Ser. 364, 283–288 (2008).CAS 
    Article 

    Google Scholar 
    Russell, L. M. et al. Ecosystem impacts of geoengineering: a review for developing a science plan. Ambio 41, 350–369 (2012).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Costello, C., Fries, L. & Gaines, S. Transformational opportunities in ocean-based food & nutrition. Zenodo https://zenodo.org/record/4646319#.YkBFxhPMLAw (2021).Jouffray, J.-B., Blasiak, R., Norström, A. V., Österblom, H. & Nyström, M. The blue acceleration: the trajectory of human expansion into the ocean. One Earth 2, 43–54 (2020).Article 

    Google Scholar 
    Cullen, J. J. & Boyd, P. W. Predicting and verifying the intended and uninterested consequence of large-scale iron fertilization. Mar. Ecol. Prog. Ser. 364, 295–301 (2008).CAS 
    Article 

    Google Scholar 
    Bach, L. T., Gill, S. J., Rickaby, R. E. M., Gore, S. & Renforth, P. CO2 removal with enhanced weathering and ocean alkalinity enhancement: potential risks and co-benefits for marine pelagic ecosystems. Front. Clim. https://doi.org/10.3389/fclim.2019.00007 (2019).Moore, C. M. et al. Processes and patterns of oceanic nutrient limitation. Nat. Geosci. 6, 701–710 (2013).CAS 
    Article 

    Google Scholar 
    Suchet, P. A., Probst, J.-L. & Ludwig, L. Worldwide distribution of continental rock lithology: implications for the atmospheric/soil CO2 uptake by continental weathering and alkalinity river transport to the oceans. Glob. Biogeochem. Cycles 17, 1038 (2003).
    Google Scholar 
    Macreadie, P. I. et al. The future of blue carbon science. Nat. Commun. 10, 3998 (2019).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Fraser, C. I., Nikula, R. & Waters, J. M. Oceanic rafting by a coastal community. Proc. Biol. Sci. 278, 649–655 (2011).PubMed 

    Google Scholar 
    Fraser, C. I., Davies, I. D., Bryant, D. & Waters, J. M. How disturbance and dispersal influence intraspecific structure. J. Ecol. 106, 1298–1306 (2018).Article 

    Google Scholar 
    Fraser, C. I. et al. Antarctica’s ecological isolation will be broken by storm-driven dispersal and warming. Nat. Clim. Change 8, 704–708 (2018).Article 

    Google Scholar 
    Chung, I. K., Beardall, J., Mehta, S., Sahoo, D. & Stojkovic, S. Using marine macroalgae for carbon sequestration: a critical appraisal. J. Appl. Phycol. 23, 877–886 (2011).CAS 
    Article 

    Google Scholar 
    Krause-Jensen, D. & Duarte, C. M. Substantial role of macroalgae in marine carbon sequestration. Nat. Geosci. 9, 737–742 (2016).CAS 
    Article 

    Google Scholar 
    Hurd, C. L. et al. Forensic carbon accounting: assessing the role of seaweeds for carbon sequestration. J. Phycol., https://doi.org/10.1111/jpy.13249 (2022).Stripe commits $8M to six new carbon removal companies. Stripe https://stripe.com/newsroom/news/spring-21-carbon-removal-purchases (2021).General application. Stripe https://github.com/stripe/carbon-removal-source-materials/blob/master/Project%20Applications/Spring2021/Running%20Tide%20-%20Stripe%20Spring21%20CDR%20Purchase%20Application.pdf (2021).Coston-Clements, L. Utilization of the Sargassum Habitat by Marine Invertebrates and Vertebrates: a Review. NOAA Technical Memorandum NMFS-SEFSC, 296 (U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Science Center & Beaufort Laboratory, 1991).Egan, S. et al. The seaweed holobiont: understanding seaweed–bacteria interactions. FEMS Microbiol. Rev. 37, 462–476 (2013).CAS 
    PubMed 
    Article 

    Google Scholar 
    Califano, G., Kwantes, M., Abreu, M. H., Costa, R. & Wichard, T. Cultivating the macroalgal holobiont: effects of integrated multi-trophic aquaculture on the microbiome of Ulva rigida (Chlorophyta)Front. Mar. Sci. 7, 52 (2020).Article 

    Google Scholar 
    Selvarajan, R. et al. Distribution, interaction and functional profiles of epiphytic bacterial communities from the rocky intertidal seaweeds, South Africa. Sci. Rep. 9, 19835 (2019).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Bonthond, G. et al. The role of host promiscuity in the invasion process of a seaweed holobiont. ISME J. 15, 1668–1679 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Wang, M. et al. The great Atlantic Sargassum belt. Science 365, 83–87 (2019).CAS 
    PubMed 
    Article 

    Google Scholar 
    Johns, E. M. et al. The establishment of a pelagic Sargassum population in the tropical Atlantic: biological consequences of a basin-scale long distance dispersal event. Prog. Oceanogr. 182, 102269 (2020).Article 

    Google Scholar 
    Martiny, A. C. et al. Biogeochemical controls of surface ocean phosphate. Sci. Adv. 5, eaax0341 (2019).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Zehr, J. P. & Capone, D. G. Changing perspectives in marine nitrogen fixation. Science 368, eaay9514 (2020).CAS 
    PubMed 
    Article 

    Google Scholar 
    Harrison, P. J., Druehl, L. D., Lloyd, K. E. & Thompson, P. A. Nitrogen uptake kinetics in three year-classes of Laminaria groenlandica (Laminariales: Phaeophyta). Mar. Biol. 93, 29–35 (1986).CAS 
    Article 

    Google Scholar 
    Hurd, C. L. & Dring, M. L. Phosphate uptake by intertidal algae in relation to zonation and season. Mar. Biol. 107, 281–289 (1990).Article 

    Google Scholar 
    Ohtake, M. et al. Growth and nutrient uptake characteristics of Sargassum macrocarpum cultivated with phosphorus-replete wastewater. Aquat. Bot. 163, 103208 (2020).Article 

    Google Scholar 
    MacFarlane, J. J. & Raven, J. A. C, N and P nutrition of Lemanea mamillosa Kütz. (Batrachospermales, Rhodophyta) in the Dighty Burn, Angus, U.K. Plant Cell Environ. 13, 1–13 (1990).CAS 
    Article 

    Google Scholar 
    Wu, J., Keller, D. P. & Oschlies, A. Carbon dioxide removal via macroalgae open-ocean mariculture and sinking: an Earth system modeling study. Preprint at Earth System Dynamics Discuss https://doi.org/10.5194/esd-2021-104 (2022).Kwiatkowski, L. et al. Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections. Biogeosciences 17, 3439–3470 (2020).CAS 
    Article 

    Google Scholar 
    Chapman, A. R. O. & Craigie, J. S. Seasonal growth in Laminaria longicruris: relations with dissolved inorganic nutrients and internal reserves of nitrogen. Mar. Biol. 40, 197–205 (1977).CAS 
    Article 

    Google Scholar 
    Dutkiewicz, S., Scott, J. R. & Follows, M. J. Winners and losers: ecological and biogeochemical changes in a warming ocean. Glob. Biogeochem. Cycles 27, 463–477 (2013).CAS 
    Article 

    Google Scholar 
    Thomas, M. K. et al. Temperature–nutrient interactions exacerbate sensitivity to warming in phytoplankton. Glob. Change Biol. 2, 3269–3280 (2017).Article 

    Google Scholar 
    Lapointe, B. E. et al. Nutrient content and stoichiometry of pelagic Sargassum reflects increasing nitrogen availability in the Atlantic Basin. Nat. Commun. 12, 3060 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Fan, W. et al. A sea trial of enhancing carbon removal from Chinese coastal waters by stimulating seaweed cultivation through artificial upwelling. Appl. Ocean Res. 101, 102260 (2020).Article 

    Google Scholar 
    Karl, D. M. & Letelier, R. M. Nitrogen fixation-enhanced carbon sequestration in low nitrate, low chlorophyll seascapes. Mar. Ecol. Prog. Ser. 364, 257–268 (2008).CAS 
    Article 

    Google Scholar 
    Oschlies, A. S., Pahlow, M., Yool, A. & Matear, R. Climate engineering by artificial ocean upwelling: channelling the sorcerer’s apprentice. Geophys. Res. Lett. 37, L04701 (2010).Article 
    CAS 

    Google Scholar 
    Thornton, D. C. O. Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean. Eur. J. Phycol. 49, 20–46 (2014).CAS 
    Article 

    Google Scholar 
    Morán, X. A. G., Sebastián, M., Pedrós-Alió, C. & Estrada, M. Response of Southern Ocean phytoplankton and bacterioplankton production to short-term experimental warming. Limnol. Oceanogr. 51, 1791–1800 (2006).Article 

    Google Scholar 
    Marañón, E., Cermeño, P., Fernández, E., Rodríguez, J. & Zabala, L. Significance and mechanisms of photosynthetic production of dissolved organic carbon in a coastal eutrophic ecosystem. Limnol. Oceanogr. 49, 1652–1666 (2004).Article 

    Google Scholar 
    Paine, E. R., Schmid, M., Boyd, P. W., Diaz-Pulido, G. & Hurd, C. L. Rate and fate of dissolved organic carbon release by seaweeds: a missing link in the coastal ocean carbon cycle. J. Phycol. 57, 1375–1391 (2021).CAS 
    PubMed 
    Article 

    Google Scholar 
    Brylinsky, M. Release of dissolved organic matter by some marine macrophytes. Mar. Biol. 39, 213–220 (1977).Article 

    Google Scholar 
    Sieburth, J. M. Studies on algal substances in the sea. III. The production of extracellular organic matter by littoral marine algae. J. Exp. Mar. Biol. Ecol. 3, 290–309 (1969).CAS 
    Article 

    Google Scholar 
    Hanson, R. B. Pelagic Sargassum community metabolism: carbon and nitrogen. J. Exp. Mar. Biol. Ecol. 29, 107–118 (1977).CAS 
    Article 

    Google Scholar 
    Zark, M., Riebesell, U. & Dittmar, T. Effects of ocean acidification on marine dissolved organic matter are not detectable over the succession of phytoplankton blooms. Sci. Adv. 1, e1500531 (2015).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Zhang, Y., Liu, X., Wang, M. & Qin, B. Compositional differences of chromophoric dissolved organic matter derived from phytoplankton and macrophytes. Org. Geochem. 55, 26–37 (2013).Article 
    CAS 

    Google Scholar 
    Hulatt, C. J., Thomas, D. N., Bowers, D. G., Norman, L. & Zhang, C. Exudation and decomposition of chromophoric dissolved organic matter (CDOM) from some temperate macroalgae. Estuar. Coast. Shelf Sci. 84, 147–153 (2009).CAS 
    Article 

    Google Scholar 
    Liu, S., Trevathan-Tackett, S. M., Ewers Lewis, C. J., Huang, X. & Macreadie, P. I. Macroalgal blooms trigger the breakdown of seagrass blue carbon. Environ. Sci. Technol. 54, 14750–14760 (2020).CAS 
    PubMed 
    Article 

    Google Scholar 
    Vieira, H. C. et al. Ocean warming may enhance biochemical alterations induced by an invasive seaweed exudate in the mussel Mytilus galloprovincialis. Toxics 9, 121 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Brooks, S. D. & Thornton, D. C. O. Marine aerosols and clouds. Ann. Rev. Mar. Sci. 10, 289–313 (2018).PubMed 
    Article 

    Google Scholar 
    Lewis, M. R., Carr, M.-E., Feldman, G. C., Esaias, W. & McClain, C. Influence of penetrating solar radiation on the heat budget of the equatorial Pacific Ocean. Nature 347, 543–545 (1990).Article 

    Google Scholar 
    Morel, A. Optical modeling of the upper ocean in relation to its biogenous matter content (case-I waters). J. Geophys. Res. 93, 10749–10768 (1988).Article 

    Google Scholar 
    Park, J.-Y., Kug, J.-S., Bader, J., Rolph, R. & Kwon, M. Amplified Arctic warming by phytoplankton under greenhouse warming. Proc. Natl Acad. Sci. USA 112, 5921–5926 (2015).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Denaro, G. et al. Dynamics of two picophytoplankton groups in Mediterranean Sea: analysis of the deep chlorophyll maximum by a stochastic advection-reaction-diffusion model. PLoS ONE 8, e66765 (2013).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Kavanaugh, M. T. et al. Experimental assessment of the effects of shade on an intertidal kelp: do phytoplankton blooms inhibit growth of open-coast macroalgae? Limnol. Oceanogr. 54, 276–288 (2009).Article 

    Google Scholar 
    Omand, M. M., Steinberg, D. K. & Stamies, K. Cloud shadows drive vertical migrations of deep-dwelling marine life. Proc. Natl Acad. Sci. USA 118, e2022977118 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Bach, L. T. & Boyd, P. W. Seeking natural analogs to fast-forward the assessment of marine CO2 removal. Proc. Natl Acad. Sci. USA 118, e2106147118 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    van Donk, E. & van de Bund, W. J. Impact of submerged macrophytes including charophytes on phyto- and zooplankton communities: allelopathy versus other mechanisms. Aquat. Bot. 72, 261–274 (2002).Article 

    Google Scholar 
    Jin, Q., Dong, S. & Wang, C. Allelopathic growth inhibition of Prorocentrum micans (Dinophyta) by Ulva pertusa and Ulva linza (Chlorophyta) in laboratory cultures. Eur. J. Phycol. 40, 31–37 (2005).Article 

    Google Scholar 
    Wallace, R. B. & Gobler, C. J.Factors controlling blooms of microalgae and macroalgae (Ulva rigida) in a eutrophic, urban estuary: Jamaica Bay, NY, USA. Estuaries Coast 38, 519–533 (2015).CAS 
    Article 

    Google Scholar 
    Tang, Y. Z. & Gobler, C. J. The green macroalga, Ulva lactuca, inhibits the growth of seven common harmful algal bloom species via allelopathy. Harmful Algae 10, 480–488 (2011).Article 

    Google Scholar 
    Cagle, S. E., Roelke, D. L. & Muhl, R. W. Allelopathy and micropredation paradigms reconcile with system stoichiometry. Ecosphere 12, e03372 (2021).Article 

    Google Scholar 
    Hein, M., Pedersen, M. F. & Sand-Jensen, K. Size-dependent nitrogen uptake in micro- and macroalgae. Mar. Ecol. Prog. Ser. 118, 247–253 (1995).Article 

    Google Scholar 
    Stevens, C. L., Hurd, C. L. & Smith, M. J. Water motion relative to subtidal kelp fronds. Limnol. Oceanogr. 46, 668–678 (2001).Article 

    Google Scholar 
    Raut, Y., Morando, M. & Capone, D. G. Diazotrophic macroalgal associations with living and decomposing Sargassum. Front. Microbiol. 9, 3127 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Villareal, T. A., Woods, S., Moore, J. K. & CulverRymsza, K. Vertical migration of Rhizosolenia mats and their significance to NO3− fluxes in the central North Pacific gyre. J. Plankton Res. 18, 1103–1121 (1996).Article 

    Google Scholar 
    Gachon, C. M. M., Sime-Ngando, T., Strittmatter, M., Chambouvet, A. & Kim, G. H. Algal diseases: spotlight on a black box. Trends Plant Sci. 15, 633–640 (2010).CAS 
    PubMed 
    Article 

    Google Scholar 
    Sánchez-Baracaldo, P., Bianchini, G., Wilson, J. D. & Knoll, A. H. Cyanobacteria and biogeochemical cycles through Earth history. Trends Microbiol. 30, 143–157 (2022).PubMed 
    Article 
    CAS 

    Google Scholar 
    Thiel, M. & Gutow, L. in Oceanography and Marine Biology: an Annual Review Vol. 43 (eds Gibson, R. et al.) 279–418 (Taylor & Francis, 2005).Rech, S., Borrell Pichs, Y. J. & García-Vazquez, E. Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna. PLoS ONE 13, e0191859 (2018).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Food and Agriculture Organization (FAO) of the United Nations. The State of World Fisheries and Aquaculture 2020: Sustainability in Action (FAO, 2020).Schell, J. M., Goodwin, D. S. & Siuda, A. N. S. Recent Sargassum inundation events in the Caribbean: shipboard observations reveal dominance of a previously rare form. Oceanography 28, 8–10 (2015).Article 

    Google Scholar 
    Rodríguez-Martínez, R. E. et al. Element concentrations in pelagic Sargassum along the Mexican Caribbean coast in 2018–2019. Peer J. 8, e8667 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Flannery, T. How farming giant seaweed can feed fish and fix the climate. The Conversation Trust https://theconversation.com/how-farming-giant-seaweed-can-feed-fish-and-fix-the-climate-81761 (2017).GESAMP. Methodology for the Evaluation of Ballast Water Management Systems Using Active Substances. GESAMP No. 101 (eds Linders, J. & Dock, A.) (International Maritime Organization, 2019).Lenton, A., Boyd, P. W., Thatcher, M. & Emmerson, K. M. Foresight must guide geoengineering research and development. Nat. Clim. Change 9, 342 (2019).Article 

    Google Scholar 
    Sumaila, U. R. Financing a sustainable ocean economy. Nat. Commun. 12, 3259 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Rockström, J. et al. Planetary boundaries: exploring the safe operating space for humanity. Ecol. Soc. 14, 32 (2009).Article 

    Google Scholar 
    Rech, S., Salmina, S., Borrell Pichs, Y. J. & García-Vazquez, E. Dispersal of alien invasive species on anthropogenic litter from European mariculture areas. Mar. Pollut. Bull. 131, 10–16 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Therriault, T. W. et al. The invasion risk of species associated with Japanese tsunami marine debris in Pacific North America and Hawaii. Mar. Pollut. Bull. 132, 82–89 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Miller, J. A., Carlton, J. T., Chapman, J. W., Geller, J. B. & Ruiz, G. M. Transoceanic dispersal of the mussel Mytilus galloprovincialis on Japanese tsunami marine debris: an approach for evaluating rafting of a coastal species at sea. Mar. Pollut. Bull. 132, 60–69 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    Carlton, J. T. et al. Tsunami-driven rafting: transoceanic species dispersal and implications for marine biogeography. Science 357, 1402–1406 (2017).CAS 
    PubMed 
    Article 

    Google Scholar 
    Hunt, G. L. Jr et al. Advection in polar and sub-polar environments: impacts on high latitude marine ecosystems. Prog. Oceanogr. 149, 40–81 (2016).Article 

    Google Scholar 
    Hallegraeff, G. M. & Bolch, C. J. Transport of dinoflagellate cysts in ship’s ballast water: implications for plankton biogeography and aquaculture. J. Plankton Res. 14, 1067–1084 (1992).Article 

    Google Scholar 
    Russell, L. K., Hepburn, C. D., Hurd, C. L. & Stuart, M. D. The expanding range of Undaria pinnatifida in southern New Zealand: distribution, dispersal mechanisms and the invasion of wave-exposed environments. Biol. Invasions 10, 103–115 (2008).Article 

    Google Scholar 
    Uwai, S. et al. Genetic diversity in Undaria pinnatifida (Laminariales, Phaeophyceae) deduced from mitochondria genes—origins and succession of introduced populations. Phycologia 45, 687–695 (2006).Article 

    Google Scholar  More