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    Convergence in phosphorus constraints to photosynthesis in forests around the world

    Beer, C. et al. Terrestrial gross carbon dioxide uptake: global distribution and covariation with climate. Science 329, 834–838 (2010).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    Luyssaert, S. et al. CO2 balance of boreal, temperate, and tropical forests derived from a global database. Glob. Change Biol. 13, 2509–2537 (2007).ADS 
    Article 

    Google Scholar 
    Pan, Y. D. et al. A large and persistent carbon sink in the world’s forests. Science 333, 988–993 (2011).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    Quesada, C. A. et al. Variations in chemical and physical properties of Amazon forest soils in relation to their genesis. Biogeosciences 7, 1515–1541 (2010).ADS 
    CAS 
    Article 

    Google Scholar 
    Wang, W. L. et al. Variations in atmospheric CO2 growth rates coupled with tropical temperature. Proc. Natl Acad. Sci. USA 110, 13061–13066 (2013).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Clark, D. A. et al. Reviews and syntheses: Field data to benchmark the carbon cycle models for tropical forests. Biogeosciences 14, 4663–4690 (2017).ADS 
    Article 

    Google Scholar 
    Huntingford, C. et al. Simulated resilience of tropical rainforests to CO2-induced climate change. Nat. Geosci. 6, 268–273 (2013).ADS 
    CAS 
    Article 

    Google Scholar 
    Fleischer, K. et al. Amazon forest response to CO2 fertilization dependent on plant phosphorus acquisition. Nat. Geosci. 12, 736–741 (2019).ADS 
    CAS 
    Article 

    Google Scholar 
    Reed, S. C. et al. Incorporating phosphorus cycling into global modeling efforts: a worthwhile, tractable endeavor. N. Phytologist 208, 324–329 (2015).CAS 
    Article 

    Google Scholar 
    Vitousek, P. M. & Howarth, R. W. Nitrogen limitation on land and in the sea – how can it occur? Biogeochemistry 13, 87–115 (1991).Article 

    Google Scholar 
    Kattge, J. et al. Quantifying photosynthetic capacity and its relationship to leaf nitrogen content for global-scale terrestrial biosphere models. Glob. Change Biol. 15, 976–991 (2009).ADS 
    Article 

    Google Scholar 
    Rogers, A. The use and misuse of Vc,max in Earth System Models. Photosynthesis Res. 119, 15–29 (2014).CAS 
    Article 

    Google Scholar 
    Field, C. B. & Mooney, H. A. in On the economy of plant form and function. (ed T. J. Givnish) 25-55. (Cambridge University Press, 1986).Cramer, W. et al. Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models. Glob. Change Biol. 7, 357–373 (2001).ADS 
    Article 

    Google Scholar 
    Goll, D. S. et al. Nutrient limitation reduces land carbon uptake in simulations with a model of combined carbon, nitrogen and phosphorus cycling. Biogeosciences 9, 3547–3569 (2012).ADS 
    CAS 
    Article 

    Google Scholar 
    Raven, J. A. Rubisco: still the most abundant protein of Earth? N. Phytologist 198, 1–3 (2013).CAS 
    Article 

    Google Scholar 
    Evans, J. R. Photosynthesis and nitrogen relationships in leaves of C3 plants. Oecologia 78, 9–19 (1989).ADS 
    PubMed 
    Article 

    Google Scholar 
    Thornton, P. E. et al. Influence of carbon-nitrogen cycle coupling on land model response to CO2 fertilization and climate variability. Glob. Biogeochem. Cycles 21, GB4018 (2007).ADS 
    Article 
    CAS 

    Google Scholar 
    Reich, P. B. et al. Leaf phosphorus influences the photosynthesis-nitrogen relation: a cross-biome analysis of 314 species. Oecologia 160, 207–212 (2009).ADS 
    PubMed 
    Article 

    Google Scholar 
    Achat, D. L. et al. Future challenges in coupled C-N-P cycle models for terrestrial ecosystems under global change: a review. Biogeochemistry 131, 173–202 (2016).CAS 
    Article 

    Google Scholar 
    Arora, V. K. et al. Carbon–concentration and carbon–climate feedbacks in CMIP6 models and their comparison to CMIP5 models. Biogeosciences 17, 4173–4222 (2020).ADS 
    CAS 
    Article 

    Google Scholar 
    Vitousek, P. M. et al. Terrestrial phosphorus limitation: mechanisms, implications, and nitrogen-phosphorus interactions. Ecol. Appl. 20, 5–15 (2010).PubMed 
    Article 

    Google Scholar 
    Du, E. et al. Global patterns of terrestrial nitrogen and phosphorus limitation. Nat. Geosci. 13, 221–226 (2020).ADS 
    CAS 
    Article 

    Google Scholar 
    Carstensen, A. et al. The impacts of phosphorus deficiency on the photosynthetic electron transport chain. Plant Physiol. 177, 271–284 (2018).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Ellsworth, D. S. et al. Phosphorus recycling in photorespiration maintains high photosynthetic capacity in woody species. Plant Cell Environ. 38, 1142–1156 (2015).CAS 
    PubMed 
    Article 

    Google Scholar 
    von Caemmerer, S. Biochemical Models of Leaf Photosynthesis. (CSIRO Publishing, 2000).Brooks, A. et al. Effects of phosphorus nutrition on the response of photosynthesis to CO2 and O2, activation of ribulose bisphosphate carboxylase and amounts of ribulose bisphosphate and 3-phosphoglycerate in spinach leaves. Photosynthesis Res. 15, 133–141 (1988).CAS 
    Article 

    Google Scholar 
    Chen, J. L. et al. Coordination theory of leaf nitrogen distribution in a canopy. Oecologia 93, 63–69 (1993).ADS 
    PubMed 
    Article 

    Google Scholar 
    Domingues, T. F. et al. Co-limitation of photosynthetic capacity by nitrogen and phosphorus in West Africa woodlands. Plant Cell Environ. 33, 959–980 (2010).CAS 
    PubMed 
    Article 

    Google Scholar 
    Farquhar, G. D. et al. A biochemical model of photosynthetic CO2 assimilation in leaves of C3 species. Planta 149, 78–90 (1980).CAS 
    PubMed 
    Article 

    Google Scholar 
    Soong, J. L. et al. Soil properties explain tree growth and mortality, but not biomass, across phosphorus-depleted tropical forests. Sci. Rep. 10, 2302 (2020).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Norby, R. J. et al. Informing models through empirical relationships between foliar phosphorus, nitrogen and photosynthesis across diverse woody species in tropical forests of Panama. N. Phytologist 215, 1425–1437 (2017).CAS 
    Article 

    Google Scholar 
    Crous, K. Y. et al. Nitrogen and phosphorus availabilities interact to modulate leaf trait scaling relationships across six plant functional types in a controlled-environment study. N. Phytologist 215, 992–1008 (2017).CAS 
    Article 

    Google Scholar 
    Domingues, T. F. et al. Parameterization of canopy structure and leaf-level gas exchange for an eastern Amazonian tropical rain forest (Tapajos National Forest, Para, Brazil). Earth Interactions 9, 17 (2005).Augusto, L. et al. Soil parent material-A major driver of plant nutrient limitations in terrestrial ecosystems. Glob. Change Biol. 23, 3808–3824 (2017).ADS 
    Article 

    Google Scholar 
    Lambers, H. et al. Plant mineral nutrition in ancient landscapes: high plant species diversity on infertile soils is linked to functional diversity for nutritional strategies. Plant Soil 347, 7–27 (2011).Article 
    CAS 

    Google Scholar 
    Yan, L. et al. Responses of foliar phosphorus fractions to soil age are diverse along a 2 Myr dune chronosequence. N. Phytologist 223, 1621–1633 (2019).CAS 
    Article 

    Google Scholar 
    Yang, X. & Post, W. M. Phosphorus transformations as a function of pedogenesis: A synthesis of soil phosphorus data using Hedley fractionation method. Biogeosciences 8, 2907–2916 (2011).ADS 
    CAS 
    Article 

    Google Scholar 
    Duursma, R. A. Plantecophys – An R package for analysing and modelling leaf gas exchange data. Plos One 10, e0143346 (2015).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Goll, D. S. et al. A representation of the phosphorus cycle for ORCHIDEE. Geoscientific Model Dev. 10, 3745–3770 (2017).ADS 
    CAS 
    Article 

    Google Scholar 
    Walker, A. P. et al. The impact of alternative trait-scaling hypotheses for the maximum photosynthetic carboxylation rate (V-cmax) on global gross primary production. N. Phytologist 215, 1370–1386 (2017).CAS 
    Article 

    Google Scholar 
    Hou, E. et al. Global meta-analysis shows pervasive phosphorus limitation of aboveground plant production in natural terrestrial ecosystems. Nat. Commun. 11, 637–645 (2020).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Kattge, J. et al. TRY plant trait database – enhanced coverage and open access. Glob. Change Biol. 26, 119–188 (2020).ADS 
    Article 

    Google Scholar 
    Neter, J. et al. Applied Linear Statistical Models, 4th ed., (McGraw-Hill, 1996).Tagesson, T. et al. Recent divergence in the contributions of tropical and boreal forests to the terrestrial carbon sink. Nat. Ecol. Evolution 4, 202–209 (2020).Article 

    Google Scholar 
    Turner, B. L. et al. Pervasive phosphorus limitation of tree species but not communities in tropical forests. Nature 490, 123–456 (2018).
    Google Scholar 
    Thornton, P. E. et al. Biospheric feedback effects in a synchronously coupled model of human and Earth systems. Nat. Clim. Chang. 7, 496-+ (2017).ADS 
    CAS 
    Article 

    Google Scholar 
    Wieder, W. R. et al. Future productivity and carbon storage limited by terrestrial nutrient availability. Nat. Geosci. 8, 441–444 (2015).ADS 
    CAS 
    Article 

    Google Scholar 
    Walker, A. P. et al. The relationship of leaf photosynthetic traits – Vcmax and Jmax – to leaf nitrogen, leaf phosphorus, and specific leaf area: a meta-analysis and modeling study. Ecol. Evolution 4, 3218–3235 (2014).Article 

    Google Scholar 
    Lambers, H. et al. Proteaceae from severely phosphorus-impoverished soils extensively replace phospholipids with galactolipids and sulfolipids during leaf development to achieve a high photosynthetic phosphorus-use-efficiency. N. Phytologist 196, 1098–1108 (2012).CAS 
    Article 

    Google Scholar 
    Jiang, M. K. et al. Towards a more physiological representation of vegetation phosphorus processes in land surface models. N. Phytologist 222, 1223–1229 (2019).Article 

    Google Scholar 
    Leuning, R. Scaling to a common temperature improves the correlation between the photosynthesis parameters Jmax and Vcmax. J. Exp. Bot. 48, 345–347 (1997).CAS 
    Article 

    Google Scholar 
    Bonardi, V. et al. Photosystem II core phosphorylation and photosynthetic acclimation require two different protein kinases. Nature 437, 1179–1182 (2005).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    Seiler, C. et al. Are terrestrial biosphere models fit for simulating the global land carbon sink? J. Adv. Model Earth Syst. 14, e2021MS002946 (2022).ADS 
    Article 

    Google Scholar 
    Goll, D. S. et al. Low phosphorus availability decreases susceptibility of tropical primary productivity to droughts. Geophys. Res. Lett. 45, 8231–8240 (2018).ADS 
    Article 

    Google Scholar 
    Sitch, S. et al. Recent trends and drivers of regional sources and sinks of carbon dioxide. Biogeosciences 12, 653–679 (2015).ADS 
    Article 

    Google Scholar 
    Wang, Y. P. et al. A global model of carbon, nitrogen and phosphorus cycles for the terrestrial biosphere. Biogeosciences 7, 2261–2282 (2010).ADS 
    CAS 
    Article 

    Google Scholar 
    Yang, X. J. et al. Phosphorus feedbacks constraining tropical ecosystem responses to changes in atmospheric CO2 and climate. Geophys. Res. Lett. 43, 7205–7214 (2016).ADS 
    CAS 
    Article 

    Google Scholar 
    Butler, E. E. et al. Mapping local and global variability in plant trait distributions. Proc. Natl Acad. Sci. USA 114, E10937–E10946 (2017).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Ellsworth, D. S. et al. Photosynthesis, carboxylation and leaf nitrogen responses of 16 species to elevated pCO2 across four free-air CO2 enrichment experiments in forest, grassland and desert. Glob. Change Biol. 10, 2121–2138 (2004).ADS 
    Article 

    Google Scholar 
    Bloomfield, K. J. et al. Contrasting photosynthetic characteristics of forest vs. savanna species (Far North Queensland, Australia). Biogeosciences 11, 7331–7347 (2014).ADS 
    Article 

    Google Scholar 
    Cernusak, L. A. et al. Photosynthetic physiology of eucalypts along a sub-continental rainfall gradient in northern Australia. Agric. For. Meteorol. 151, 1462–1470 (2011).ADS 
    Article 

    Google Scholar 
    Bahar, N. H. A. et al. Leaf-level photosynthetic capacity in lowland Amazonian and high-elevation Andean tropical moist forests of Peru. N. Phytologist 214, 1002–1018 (2017).CAS 
    Article 

    Google Scholar 
    Rowland, L. et al. After more than a decade of soil moisture deficit, tropical rainforest trees maintain photosynthetic capacity, despite increased leaf respiration. Glob. Change Biol. 21, 4662–4672 (2015).ADS 
    Article 

    Google Scholar 
    Domingues, T. F. et al. Seasonal patterns of leaf-level photosynthetic gas exchange in an eastern Amazonian rain forest. Plant Ecol. Diversity 7, 189–203 (2014).Article 

    Google Scholar 
    Kenzo, T. et al. Changes in photosynthesis and leaf characteristics with tree height in five dipterocarp species in a tropical rain forest. Tree Physiol. 26, 865–873 (2006).CAS 
    PubMed 
    Article 

    Google Scholar 
    van de Weg, M. J. et al. Photosynthetic parameters, dark respiration and leaf traits in the canopy of a Peruvian tropical montane cloud forest. Oecologia 168, 23–34 (2012).ADS 
    PubMed 
    Article 

    Google Scholar 
    Kenzo, T. et al. Variations in leaf photosynthetic and morphological traits with tree height in various tree species in a Cambodian tropical dry evergreen forest. Jpn. Agriculture Res. Q. 46, 167–180 (2012).Article 

    Google Scholar 
    Domingues, T. F. et al. Biome-specific effects of nitrogen and phosphorus on the photosynthetic characteristics of trees at a forest-savanna boundary in Cameroon. Oecologia 178, 659–672 (2015).ADS 
    PubMed 
    Article 

    Google Scholar 
    Verryckt, L. T. et al. Vertical profiles of leaf photosynthesis and leaf traits and soil nutrients in two tropical rainforests in French Guiana before and after a 3-year nitrogen and phosphorus addition experiment. Earth Syst. Sci. Data 14, 5–18 (2022).ADS 
    Article 

    Google Scholar 
    Santiago, L. S. & Mulkey, S. S. A test of gas exchange measurements on excised canopy branches of ten tropical tree species. Photosynthetica 41, 343–347 (2003).CAS 
    Article 

    Google Scholar 
    Medlyn, B. E. et al. Linking leaf and tree water use with an individual-tree model. Tree Physiol. 27, 1687–1699 (2007).PubMed 
    Article 

    Google Scholar 
    Fick, S. E. & Hijmans, R. J. Worldclim 2: New 1-km spatial resolution climate surfaces for global land areas. Int. J. Climatol. 37, 4302–4315 (2017).Article 

    Google Scholar 
    Townsend, A. R. et al. Controls over foliar N:P ratios in tropical rain forests. Ecology 88, 107–118 (2007).PubMed 
    Article 

    Google Scholar 
    Wright, I. J. et al. The worldwide leaf economics spectrum. Nature 428, 821–827 (2004).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    Reich, P. B. et al. Leaf structure (specific leaf area) modulates photosynthesis- nitrogen relations: evidence from within and across species and functional groups. Funct. Ecol. 12, 948–958 (1998).Article 

    Google Scholar 
    Rogers, A. et al. Improving representation of photosynthesis in Earth System Models. N. Phytologist 204, 12–14 (2014).Article 

    Google Scholar 
    Kumarathunge, D. P. et al. Acclimation and adaptation components of the temperature dependence of plant photosynthesis at the global scale. N. Phytologist 222, 768–784 (2019).CAS 
    Article 

    Google Scholar 
    Warton, D. I. et al. Bivariate line-fitting methods for allometry. Biol. Rev. 81, 259–291 (2006).PubMed 
    Article 

    Google Scholar 
    Krinner, G. et al. A dynamic global vegetation model for studies of the coupled atmosphere-biosphere system. Global Biogeochem. Cycles 19, GB1015 (2005).ADS 
    Article 
    CAS 

    Google Scholar 
    Koerselman, W. & Meuleman, A. F. M. The vegetation N: P ratio: a new tool to detect the nature of nutrient limitation. J. Appl. Ecol. 33, 1441–1450 (1996).Article 

    Google Scholar 
    Tian, H. Q. et al. Global soil nitrous oxide emissions since the preindustrial era estimated by an ensemble of terrestrial biosphere models: Magnitude, attribution, and uncertainty. Glob. Change Biol. 25, 640–659 (2019).ADS 
    Article 

    Google Scholar  More

  • in

    Fungal succession on the decomposition of three plant species from a Brazilian mangrove

    Raghukumar, S. Fungi in coastal and oceanic marine ecosystems: Marine fungi. Fungi Coast. Ocean. Mar. Ecosyst. Mar. Fungi. https://doi.org/10.1007/978-3-319-54304-8 (2017).Article 

    Google Scholar 
    Holguin, G., Vazquez, P. & Bashan, Y. The role of sediment microorganisms in the productivity, conservation, and rehabilitation of mangrove ecosystems: An overview. Biol. Fertil. Soils 33, 265–278 (2001).CAS 
    Article 

    Google Scholar 
    Sebastianes, F. L. D. S. et al. Species diversity of culturable endophytic fungi from Brazilian mangrove forests. Curr. Genet. 59, 153–166 (2013).CAS 
    Article 

    Google Scholar 
    Holguin, G. et al. Mangrove health in an arid environment encroached by urban development—A case study. Sci. Total Environ. 363, 260–274 (2006).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    Schaeffer-Novelli, Y., Cintrón-Molero, G. & Adaime, R. R. Variability of Mangrove ecosystems along the Brazilian coast variability of mangrove ecosystems along the Brazilian Coast. Estuaries 13, 204–218 (1990).Article 

    Google Scholar 
    Baskaran, R., Mohan, P., Sivakumar, K., Ragavan, P. & Sachithanandam, V. Phyllosphere microbial populations of ten true mangrove species of the Andaman Island. Int. J. Microbiol. Res. 3, 124–127 (2012).
    Google Scholar 
    Alongi, D. M. The role of bacteria in nutrient recycling in tropical mangrove and other coastal benthic ecosystems. Hydrobiologia 285, 19–32 (1994).CAS 
    Article 

    Google Scholar 
    Taketani, R. G., Moitinho, M. A., Mauchline, T. H. & Melo, I. S. Co-occurrence patterns of litter decomposing communities in mangroves indicate a robust community resistant to disturbances. PeerJ 6, e5710 (2018).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Schmit, J. P. & Mueller, G. M. An estimate of the lower limit of global fungal diversity. Biodivers. Conserv. 16, 99–111 (2007).Article 

    Google Scholar 
    Hawksworth, D. L. Fungal diversity and its implications for genetic resource collections. Stud. Mycol. 50, 9–18 (2004).
    Google Scholar 
    Valderrama, B. et al. Assessment of non-cultured aquatic fungal diversity from different habitats in Mexico. Revista Mexicana de Biodiversidad 87, 18–28 (2016).Article 

    Google Scholar 
    Marano, A. V., Pires-Zottarelli, C. L. A., Barrera, M. D., Steciow, M. M. & Gleason, F. H. Diversity, role in decomposition, and succession of zoosporic fungi and straminipiles on submerged decaying leaves in a woodland stream. Hydrobiologia 659, 93–109 (2011).Article 

    Google Scholar 
    Pascoal, C. & Cassio, F. Contribution of fungi and bacteria to leaf litter decomposition in a polluted river. Appl. Environ. Microbiol. 70, 5266–5273 (2004).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Moitinho, M. A., Bononi, L., Souza, D. T., Melo, I. S. & Taketani, R. G. Bacterial succession decreases network complexity during plant material decomposition in mangroves. Microb. Ecol. https://doi.org/10.1007/s00248-018-1190-4 (2018).Article 
    PubMed 

    Google Scholar 
    Tan, T. K., Leong, W. F. & Jones, E. B. G. Succession of fungi on wood of Avicennia alba and A. lanata in Singapore. Can. J. Bot. 67, 2686–2691 (1989).Article 

    Google Scholar 
    Ananda, K. & Sridhar, K. R. Diversity of filamentous fungi on decomposing leaf and woody litter of mangrove forests in the southwest coast of India. Curr. Sci. 80, 1431–1437 (2004).
    Google Scholar 
    Maria, G. L., Sridhar, K. R. & Bärlocher, F. Decomposition of dead twigs of Avicennia officinalis and Rhizophora mucronata in a mangrove in southwestern India. Bot. Mar. 49, 450–455 (2006).CAS 
    Article 

    Google Scholar 
    Baldrian, P. et al. Active and total microbial communities in forest soil are largely different and highly stratified during decomposition. ISME J. 6, 248–258 (2012).CAS 
    PubMed 
    Article 

    Google Scholar 
    Gardes, M. & Bruns, T. D. ITS primers with enhanced specificity for basidiomycetes—Application to the identification of mycprrhizae and rusts. Mol. Ecol. 2, 113–118 (1993).CAS 
    PubMed 
    Article 

    Google Scholar 
    White, T. J., Bruns, T., Lee, S. & Taylor, J. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In PCR Protocols: A Guide to Methods and Applications (eds Innis, M. et al.) 315–322 (Academic Press, 1990).
    Google Scholar 
    Caporaso, J. G. et al. QIIME allows analysis of high-throughput community sequencing data. Nat. Methods 7, 335–336 (2010).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Kõljalg, U. et al. Towards a unified paradigm for sequence-based identification of fungi. Mol. Ecol. 22, 5271–5277 (2013).PubMed 
    Article 
    CAS 

    Google Scholar 
    Mcmurdie, P. J. & Holmes, S. phyloseq : An R package for reproducible interactive analysis and graphics of microbiome census data. 8, (2013).Oksanen, P. Vegan 1.17-0. (2010).Wickham, H. ggplot2: Elegant Graphics for Data Analysis (Springer, 2009).MATH 
    Book 

    Google Scholar 
    Hamilton, N. E. & Ferry, M. {ggtern}: Ternary diagrams using {ggplot2}. J. Stat. Softw. Code Snippets 87, 1–17 (2018).
    Google Scholar 
    Hanski, I. Communities of bumblebees: Testing the core-satellite species hypothesis. Annales Zoologici Fennici 65–73 (1982).Gumiere, T. et al. A probabilistic model to identify the core microbial community. bioRxiv. https://doi.org/10.1101/491183 (2018).Article 

    Google Scholar 
    Salazar, G. EcolUtils: Utilities for community ecology analysis. (2019).Levins, R. Evolution in Changing Environments: Some Theoretical Explorations (Princeton University Press, 1968).Book 

    Google Scholar 
    Nguyen, N. H. et al. FUNGuild: An open annotation tool for parsing fungal community datasets by ecological guild. Fungal Ecol. 20, 241–248 (2016).Article 

    Google Scholar 
    Promputtha, I. et al. Fungal succession on senescent leaves of Castanopsis diversifolia in Doi Suthep-Pui National Park, Thailand. Fungal Diversity 30, 23–36 (2008).
    Google Scholar 
    Kodsueb, R., McKenzie, E. H. C., Lumyong, S. & Hyde, K. D. Fungal succession on woody litter of Magnolia liliifera (Magnoliaceae). Fungal Diversity 30, 55–72 (2008).
    Google Scholar 
    Voriskova, J. & Baldrian, P. Fungal community on decomposing leaf litter undergoes rapid successional changes. ISME J. 7, 477–486 (2013).CAS 
    PubMed 
    Article 

    Google Scholar 
    Osono, T. Phyllosphere fungi on leaf litter of Fagus crenata: Occurrence, colonization, and succession. Can. J. Bot. 80, 460–469 (2002).Article 

    Google Scholar 
    Osono, T. et al. Fungal succession and lignin decomposition on Shorea obtusa leaves in a tropical seasonal forest in northern Thailand. Fungal Diversity 36, 101–119 (2009).
    Google Scholar 
    Costa, I. P. M. W., Maia, L. C. & Cavalcanti, M. A. Diversity of leaf endophytic fungi in mangrove plants of Northeast Brazil. Braz. J. Microbiol. 43, 1165–1173 (2012).Article 

    Google Scholar 
    Sobrado, M. A. Influence of external salinity on the osmolality of xylem sap, leaf tissue and leaf gland secretion of the mangrove Laguncularia racemosa (L.) Gaertn. 422–427 (2004). https://doi.org/10.1007/s00468-004-0320-4.Dias, A. C. F. et al. Interspecific variation of the bacterial community structure in the phyllosphere of the three major plant components of mangrove forests. Braz. J. Microbiol. 43, (2012).Moitinho, M. A. et al. Intraspecific variation on epiphytic bacterial community from Laguncularia racemosa phylloplane. Braz. J. Microbiol. 50, 1041–1050 (2019).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Barroso-Matos, T., Bernini, E. & Rezende, C. E. Descomposición de hojas de mangle en el estuario del Río Paraíba do Sul Rio de Janeiro, Brasil. Lat. Am. J. Aquat. Res. 40, 398–407 (2012).Article 

    Google Scholar 
    Sessegolo, G. C. & Lana, P. C. Lagunculana racemosa Leaves in a Mangrove of Paranaguä Bay (Southeastern Brazil). Bot. Mar. 34, 285–289 (1991).Article 

    Google Scholar 
    Miura, T. et al. Diversity of fungi on decomposing leaf litter in a sugarcane plantation and their response to tillage practice and bagasse mulching: implications for management effects on litter decomposition. Microb. Ecol. 70, 646–658 (2015).PubMed 
    Article 

    Google Scholar 
    Behnke-Borowczyk, J. & Wołowska, D. The identification of fungal species in dead wood of oak. Acta Scientiarum Polonorum Silvarum Colendarum Ratio et Industria Lignaria 17, 17–23 (2018).Article 

    Google Scholar 
    Simões, M. F. et al. Soil and rhizosphere associated fungi in gray mangroves (Avicennia marina) from the Red Sea—A metagenomic approach. Genom. Proteom. Bioinform. 13, 310–320 (2015).Article 

    Google Scholar 
    Osono, T. Ecology of ligninolytic fungi associated with leaf litter decomposition. Ecol. Res. 22, 955–974 (2007).Article 

    Google Scholar 
    Zhang, W. et al. Relationship between soil nutrient properties and biological activities along a restoration chronosequence of Pinus tabulaeformis plantation forests in the Ziwuling Mountains, China. CATENA 161, 85–95 (2018).CAS 
    Article 

    Google Scholar 
    Jones, E. B. G. & Choeyklin, R. Ecology of marine and freshwater basidiomycetes. in Ecology of Saprotrophic Basidiomycetes 301–324 (2007).Schneider, T. et al. Who is who in litter decomposition? Metaproteomics reveals major microbial players and their biogeochemical functions. ISME J. 6, 1749–1762 (2012).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Zhang, X. et al. Diversity and dynamics of the microbial community on decomposing wheat straw during mushroom compost production. Biores. Technol. 170, 183–195 (2014).CAS 
    Article 

    Google Scholar 
    Koivusaari, P. et al. Fungi originating from tree leaves contribute to fungal diversity of litter in streams. Front. Microbiol. 10, (2019).Raudabaugh, D. B. et al. Coniella lustricola, a new species from submerged detritus. Mycol. Prog. 17, 191–203 (2018).Article 

    Google Scholar 
    Arfi, Y. et al. Characterization of salt-adapted secreted lignocellulolytic enzymes from the mangrove fungus Pestalotiopsis sp. Nat. Commun. 4, (2013). More

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    A divergent bacterium lives in association with bacterivorous protists in the ocean

    Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.This is a summary of: Needham, D. M. et al. The microbiome of a bacterivorous marine choanoflagellate contains a resource-demanding obligate bacterial associate. Nat. Microbiol. https://doi.org/10.1038/s41564-022-01174-0 (2022). More

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    Morpho-functional traits of the coral Stylophora pistillata enhance light capture for photosynthesis at mesophotic depths

    Graham, N. A. J. & Nash, K. L. The importance of structural complexity in coral reef ecosystems. Coral Reefs https://doi.org/10.1007/s00338-012-0984-y (2013).Drake, J. L. et al. How corals made rocks through the ages. Glob. Change Biol. 26, 31–53 (2020).Zawada, K. J. A., Madin, J. S., Baird, A. H., Bridge, T. C. L. & Dornelas, M. Morphological traits can track coral reef responses to the Anthropocene. Funct. Ecol. 33, 962–975 (2019).Article 

    Google Scholar 
    Wehrberger, F. & Herler, J. Microhabitat characteristics influence shape and size of coral-associated fishes. Mar. Ecol. Prog. Ser. 500, 203–214 (2014).Article 

    Google Scholar 
    Munday, P. & Jones, G. The ecological implications of small body size among coral-reef fishes. Oceanogr. Mar. Biol. 36, 373–411 (1998).
    Google Scholar 
    Pereira, P. H. C. & Munday, P. L. Coral colony size and structure as determinants of habitat use and fitness of coral-dwelling fishes. Mar. Ecol. Prog. Ser. 553, 163–172 (2016).Article 

    Google Scholar 
    Doszpot, N., McWilliam, M., Pratchett, M., Hoey, A. & Figueira, W. Plasticity in three-dimensional geometry of branching corals along a cross-shelf gradient. Diversity 11, 44 (2019).Article 

    Google Scholar 
    Ow, Y. X. & Todd, P. A. Light-induced morphological plasticity in the scleractinian coral Goniastrea pectinata and its functional significance. Coral Reefs 29, 797–808 (2010).Article 

    Google Scholar 
    Soto, D., De Palmas, S., Ho, M. J., Denis, V. & Chen, C. A. Spatial variation in the morphological traits of Pocillopora verrucosa along a depth gradient in Taiwan. PLoS ONE 13, 1–20 (2018).Article 
    CAS 

    Google Scholar 
    Bruno, J. F. & Edmunds, P. J. Clonal variation for phenotypic plasticity in the coral Madracis Mirabilis. Ecology 78, 2177–2190 (1997).Article 

    Google Scholar 
    Todd, P. A. Morphological plasticity in scleractinian corals. Biol. Rev. 83, 315–337 (2008).Willis, B. L. Phenotypic plasticity versus phenotypic stability in the reef corals Turbinaria mesenterina and Pavona cactus. Proc. Fifth Int. Coral Reef. Symp. 4, 107–112 (1985).
    Google Scholar 
    Grottoli, A. G. et al. The cumulative impact of annual coral bleaching can turn some coral species winners into losers. Glob. Change Biol. 20, 3823–3833 (2014).Article 

    Google Scholar 
    Smith, L. W., Barshis, D. & Birkeland, C. Phenotypic plasticity for skeletal growth, density and calcification of Porites lobata in response to habitat type. Coral Reefs 26, 559–567 (2007).Article 

    Google Scholar 
    Barnes, D. Growth in colonial scleractinians. Bull. Marine Sci. 280–298 (1973).Anthony, K. R. N. & Hoegh-Guldberg, O. Variation in coral photosynthesis, respiration and growth characteristics in contrasting light microhabitats: an analogue to plants in forest gaps and understoreys? Funct. Ecol. 17, 246–259 (2003).Article 

    Google Scholar 
    Kramer, N., Tamir, R., Eyal, G. & Loya, Y. Coral morphology portrays the spatial distribution and population size-structure along a 5–100 m depth gradient. Front. Mar. Sci. 7, 615 (2020).Article 

    Google Scholar 
    Dubé, C. E., Mercière, A., Vermeij, M. J. A. & Planes, S. Population structure of the hydrocoral Millepora platyphylla in habitats experiencing different flow regimes in Moorea, French polynesia. PLoS ONE 12, 1–20 (2017).
    Google Scholar 
    Chappell, J. Coral morphology, diversity and reef growth. Nature 286, 249–252 (1980).Article 

    Google Scholar 
    Paz-García, D. A. et al. Morphological variation and different branch modularity across contrasting flow conditions in dominant Pocillopora reef-building corals. Oecologia 178, 207–218 (2015).PubMed 
    Article 

    Google Scholar 
    Laverick, J. H., Tamir, R., Eyal, G. & Loya, Y. A generalized light-driven model of community transitions along coral reef depth gradients. Glob. Ecol. Biogeogr. 29, 1554–1564 (2020).Article 

    Google Scholar 
    Bongaerts, P., Ridgway, T., Sampayo, E. M. & Hoegh-Guldberg, O. Assessing the “deep reef refugia” hypothesis: focus on Caribbean reefs. Coral Reefs 29, 1–19 (2010).Article 

    Google Scholar 
    Sherman, C. E., Locker, S. D., Webster, J. M. & Weinstein, D. K. In Mesophotic Coral Ecosystems (eds. Loya, Y., Puglise, K. A. & Bridge, T. C. L.) 849–878 (Springer International Publishing, 2019).Kahng, S. E., Copus, J. M. & Wagner, D. Recent advances in the ecology of mesophotic coral ecosystems (MCEs). Curr. Opin. Environ. Sustainability 7, 72–81 (2014).Article 

    Google Scholar 
    Tamir, R., Eyal, G., Kramer, N., Laverick, J. H. & Loya, Y. Light environment drives the shallow to mesophotic coral community transition. Ecosphere 10, e02839 (2019).Article 

    Google Scholar 
    Lichtenthaler, H. K., Ač, A., Marek, M. V., Kalina, J. & Urban, O. Differences in pigment composition, photosynthetic rates and chlorophyll fluorescence images of sun and shade leaves of four tree species. Plant Physiol. Biochem. 45, 577–588 (2007).CAS 
    PubMed 
    Article 

    Google Scholar 
    Bragg, J. G. & Westoby, M. Leaf size and foraging for light in a sclerophyll woodland. Funct. Ecol. 16, 633–639 (2002).Article 

    Google Scholar 
    Sæbø, A., Krekling, T. & Appelgren, M. Light quality affects photosynthesis and leaf anatomy of birch plantlets in vitro. Plant Cell, Tissue Organ Cult. 41, 177–185 (1995).Article 

    Google Scholar 
    Einbinder, S. et al. Changes in morphology and diet of the coral Stylophora pistillata along a depth gradient. Mar. Ecol. Prog. Ser. 381, 167–174 (2009).Article 

    Google Scholar 
    Mass, T. et al. Photoacclimation of Stylophora pistillata to light extremes: metabolism and calcification. Mar. Ecol. Prog. Ser. 334, 93–102 (2007).CAS 
    Article 

    Google Scholar 
    Kramer, N. et al. Efficient light-harvesting of mesophotic corals is facilitated by coral optical traits. Funct. Ecol. 36, 406–418 (2022).CAS 
    Article 

    Google Scholar 
    Einbinder, S. et al. Novel adaptive photosynthetic characteristics of mesophotic symbiotic microalgae within the reef-building coral, Stylophora pistillata. Front. Mar. Sci. 3, 195 (2016).Article 

    Google Scholar 
    Martinez, S. et al. Energy sources of the depth-generalist mixotrophic coral Stylophora pistillata. Front. Mar. Sci. 7, 1–16 (2020).CAS 
    Article 

    Google Scholar 
    Anthony, K. R. N., Hoogenboom, M. O. & Connolly, S. R. Adaptive variation in coral geometry and the optimization of internal colony light climates. Funct. Ecol. 19, 17–26 (2005).Article 

    Google Scholar 
    Kahng, S. E., Watanabe, T. K., Hu, H.-M., Watanabe, T. & Shen, C.-C. Moderate zooxanthellate coral growth rates in the lower photic zone. Coral Reefs https://doi.org/10.1007/s00338-020-01960-4 (2020).Wangpraseurt, D. et al. The in situ light microenvironment of corals. Limnol. Oceanogr. 59, 917–926 (2014).Article 

    Google Scholar 
    Dustan, P. Depth-dependent photoadaption by zooxanthellae of the reef coral Montastrea annularis. Mar. Biol. 68, 253–264 (1982).CAS 
    Article 

    Google Scholar 
    Dubinsky, Z., Falkowski, P. G., Porter, J. W. & Muscatine, L. Absorption and utilization of radiant energy by light- and shade-adapted colonies of the hermatypic coral Stylophora pistillata. Proc. R. Soc. B: Biol. Sci. 222, 203–214 (1984).CAS 

    Google Scholar 
    Falkowski, P. G. & Dubinsky, Z. Light-shade adaptation of Stylophora pistillata, a hermatypic coral from the Gulf of Eilat. Nature 289, 172–174 (1981).Article 

    Google Scholar 
    Kahng, S. E. et al. In Mesophotic Coral Ecosystems (eds. Loya, Y., Puglise, K. A. & Bridge, T. C. L.) 801–828 (Springer International Publishing, 2019).Hoogenboom, M. O., Connolly, S. R. & Anthony, K. R. N. Interactions between morphological and physiological plasticity optimize energy acquisition in corals. Ecology 89, 1144–1154 (2008).PubMed 
    Article 

    Google Scholar 
    House, J. E. et al. Moving to 3D: relationships between coral planar area, surface area and volume. PeerJ 6, e4280 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Zawada, K. J. A., Dornelas, M. & Madin, J. S. Quantifying coral morphology. Coral Reefs 38, 1281–1292 (2019).Article 

    Google Scholar 
    Malik, A. et al. Molecular and skeletal fingerprints of scleractinian coral biomineralization: From the sea surface to mesophotic depths. Acta Biomaterialia 1–14 https://doi.org/10.1016/j.actbio.2020.01.010 (2020).Todd, P. A., Ladle, R. J., Lewin-Koh, N. J. I. & Chou, L. M. Genotype x environment interactions in transplanted clones of the massive corals Favia speciosa and Diploastrea heliopora. Mari. Ecol. Prog. Ser. https://doi.org/10.3354/meps271167 (2004).Crabbe, M. J. C. & Smith, D. J. Modelling variations in corallite morphology of Galaxea fascicularis coral colonies with depth and light on coastal fringing reefs in the Wakatobi Marine National Park (S.E. Sulawesi, Indonesia). Computational Biol. Chem. 30, 155–159 (2006).CAS 
    Article 

    Google Scholar 
    Studivan, M. S., Milstein, G. & Voss, J. D. Montastraea cavernosa corallite structure demonstrates distinct morphotypes across shallow and mesophotic depth zones in the Gulf of Mexico. PLoS ONE 14, e0203732 (2019).Wangpraseurt, D., Larkum, A. W. D., Ralph, P. J. & Kühl, M. Light gradients and optical microniches in coral tissues. Front. Microbiol. 3, 1–9 (2012).Article 

    Google Scholar 
    Enríquez, S., Méndez, E. R. & Iglesias-Prieto, R. Multiple scattering on coral skeletons enhances light absorption by symbiotic algae. Limnol. Oceanogr. 50, 1025–1032 (2005).Article 

    Google Scholar 
    Wangpraseurt, D., Jacques, S. L., Petrie, T. & Kühl, M. Monte Carlo modeling of photon propagation reveals highly scattering coral tissue. Front. Plant Sci. 7, 1–10 (2016).Article 

    Google Scholar 
    Muko, S., Kawasaki, K., Sakai, K., Takasu, F. & Shigesada, N. Morphological plasticity in the coral Porites sillimaniani and its adaptive significance. Bull. Mar. Sci. 66, 225–239 (2000).
    Google Scholar 
    Klaus, J. S., Budd, A. F. & Fouke, B. Environmental controls on corallite morphology in the reef coral Montastraea annularis Hot springs microbiology View project Positive Accretion in the Deep: Carbonate budget analysis of Caribbean mesophotic coral reef habitats View project. Bull. Mar. Sci. 80, 233–260 (2007).
    Google Scholar 
    Enríquez, S., Méndez, E. R., Hoegh-Guldberg, O. & Iglesias-Prieto, R. Key functional role of the optical properties of coral skeletons in coral ecology and evolution. Proc. R. Soc. B: Biol. Sci. 284, (2017).Wangpraseurt, D. et al. Microscale light management and inherent optical properties of intact corals studied with optical coherence tomography. J. R. Soc. Interface 16, 20180567 (2019).Groves, S. H. et al. Growth rates of Porites astreoides and Orbicella franksi in mesophotic habitats surrounding St. Thomas, US Virgin Islands. Coral Reefs 37, 345–354 (2018).Article 

    Google Scholar 
    Shlesinger, T., Grinblat, M., Rapuano, H., Amit, T. & Loya, Y. Can mesophotic reefs replenish shallow reefs? Reduced coral reproductive performance casts a doubt. Ecology https://doi.org/10.1002/ecy.2098 (2018).Kaniewska, P. et al. Importance of macro- versus microstructure in modulating light levels inside coral colonies. J. Phycol. 47, 846–860 (2011).PubMed 
    Article 

    Google Scholar 
    Swain, T. D. et al. Relating coral skeletal structures at different length scales to growth, light availability to symbiodinium, and thermal bleaching. Front. Mar. Sci. 5, (2018).Bongaerts, P. & Smith, T. B. In Mesophotic Coral Ecosystems (eds. Loya, Y., Puglise, K. A. & Bridge, T. C. L.) 881–895 (Springer International Publishing, 2019).Bongaerts, P., Riginos, C., Brunner, R., Englebert, N. & Smith, S. R. Deep reefs are not universal refuges: reseeding potential varies among coral species. Sci. Adv. 3, 1–40 (2017).Article 

    Google Scholar 
    Serrano, X. M. et al. Long distance dispersal and vertical gene flow in the Caribbean brooding coral Porites astreoides. Sci. Rep. 6, 21619 (2016).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Fantazzini, P. et al. Gains and losses of coral skeletal porosity changes with ocean acidification acclimation. Nat. Commun. 6, 7785 (2015).Mollica, N. R. et al. Ocean acidification affects coral growth by reducing skeletal density. Proc. Natl Acad. Sci. USA 115, 1754–1759 (2018).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Fordyce, A. J., Ainsworth, T. D., Leggat, W. & Katherine, M. Light capture, skeletal morphology, and the biomass of corals’ boring endoliths. mSphere 6, e00060–21 (2021).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Muscatine, L. The role of symbiotic algae in carbon and energy flux in coral reefs. Ecosyst. World 25, 75–87 (1990).
    Google Scholar 
    Houlbrèque, F. & Ferrier-Pagès, C. Heterotrophy in tropical scleractinian corals. Biol. Rev. 84, 1–17 (2009).PubMed 
    Article 

    Google Scholar 
    Tremblay, P., Gori, A., Maguer, J. F., Hoogenboom, M. & Ferrier-Pagès, C. Heterotrophy promotes the re-establishment of photosynthate translocation in a symbiotic coral after heat stress. Sci. Rep. 6, 38112 (2016).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Lesser, M. P. et al. Photoacclimatization by the coral Montastraea cavernosa in the mesophotic zone: light, food, and genetics. Ecology https://doi.org/10.1890/09-0313.1 (2010).Pinheiro, H. T., Eyal, G., Shepherd, B. & Rocha, L. A. Ecological insights from environmental disturbances in mesophotic coral ecosystems. Ecosphere 10, e02666 (2019).Article 

    Google Scholar 
    Wangpraseurt, D. et al. In vivo microscale measurements of light and photosynthesis during coral bleaching: evidence for the optical feedback loop? Front. Microbiol. 8, 1–12 (2017).Article 

    Google Scholar 
    Veron, C., Stafford-Smith, M., Turak, E. & DeVantier, L. Corals of the World (Australian Institute of Marine Science, 2000).Loya, Y. The Red Sea coral Stylophora pistillata is an r strategist. Nature 259, 478–480 (1976).Article 

    Google Scholar 
    Drake, J. L. et al. Physiological and transcriptomic variability indicative of differences in key functions within a single coral colony. Front. Mar. Sci. 8, 768 (2021).Article 

    Google Scholar 
    Jacques, S., Li, T. & Prahl, S. mcxyz. c, a 3D Monte Carlo simulation of heterogeneous tissues. omlc.org/software/mc/mcxyz (2013).Tuchin, V. V. Tissue Optics: Light Scattering Methods and Instruments for Medical Diagnostics (SPIE PRESS, 2015).Wang, L., Jacques, S. L. & Zheng, L. MCML—Monte Carlo modeling of light transport in multi-layered tissues. Computer Methods Prog. Biomed. 47, 131–146 (1995).CAS 
    Article 

    Google Scholar 
    Jacques, S. L., Wangpraseurt, D. & Kühl, M. Optical properties of living corals determined with diffuse reflectance. Spectrosc. Front Mar. Sci. 6, 1–9 (2019).Article 

    Google Scholar 
    Hill, R. et al. Spatial heterogeneity of photosynthesis and the effect of temperature-induced bleaching conditions in three species of corals. Mar. Biol. 144, 633–640 (2004).Article 

    Google Scholar 
    Ritchie, R. J. & Larkum, A. W. D. Modelling photosynthesis in shallow algal production ponds. Photosynthetica 50, 481–500 (2012).CAS 
    Article 

    Google Scholar 
    Team, R. C. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/ (2022).Bates, D., Mächler, M., Bolker, B. & Walker, S. Fitting linear mixed-effects models using {lme4}. J. Stat. Softw. 67, 1–48 (2015).Article 

    Google Scholar 
    Luo, D., Ganesh, S. & Koolaard, J. predictmeans: calculate predicted means for linear models. Preprint at https://CRAN.R-project.org/package=predictmeans (2021).Clarke, K. R. Non‐parametric multivariate analyses of changes in community structure. Aust. J. Ecol. 18, 117–143 (1993).Article 

    Google Scholar 
    Kramer, N., Guan, J., Chen, S., Wangpraseurt, D. & Loya, Y. Morpho-functional traits of the coral Stylophora pistillata enhance light capture for photosynthesis at mesophotic depths. Dryad, Dataset https://doi.org/10.5061/dryad.7d7wm37w7 (2022). More

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    Initial community composition determines the long-term dynamics of a microbial cross-feeding interaction by modulating niche availability

    The generalist accumulates extracellular nitriteWe first tested whether the generalist accumulates substantial extracellular nitrite under our experimental conditions, and thus creates a niche for the specialist. To accomplish this, we grew the generalist alone in bioreactors with anoxic ACS medium amended with 12 mM nitrate as the growth-limiting substrate and measured the extracellular concentrations of nitrate and nitrite over time. We performed these experiments at pH 6.5 (strong nitrite toxicity) and 7.5 (weak nitrite toxicity).We observed a substantial accumulation of extracellular nitrite regardless of the pH (Fig. 3A, B). When grown at pH 6.5 (strong nitrite toxicity), extracellular nitrite accumulated to a concentration comparable to the initial nitrate concentration (measured maximum extracellular nitrite concentration, 11.8 mM; measured initial nitrate concentration, 12.0 mM) and was subsequently consumed to below the detection limit (Fig. 3A). When grown at pH 7.5 (weak nitrite toxicity), extracellular nitrite again accumulated to a concentration comparable to the initial nitrate concentration (measured maximum extracellular nitrite concentration, 11.7 mM; measured initial nitrate concentration, 12.9 mM) and was subsequently consumed to below the detection limit (Fig. 3B). During growth at pH 6.5, substantial nitrite consumption did not begin until a prolonged period of time after nitrate consumption was complete, resulting in a relatively long duration of nitrite availability (Fig. 3A). During growth at pH 7.5, in contrast, substantial nitrite consumption began immediately after nitrate consumption was complete, resulting in a relatively short duration of nitrite availability (Fig. 3B). The longer duration of nitrite availability at pH 6.5 indicates that the duration of the niche created by the generalist for the specialist depends on pH.Fig. 3: Growth and nitrogen oxide dynamics of the generalist in batch culture.We grew the generalist alone in a bioreactor at A pH 7.5 (weak nitrite toxicity) or B pH 6.5 (strong nitrite toxicity) under anoxic conditions with nitrate as the growth-limiting substrate. Blue squares are measured extracellular nitrate concentrations, yellow triangles are measured extracellular nitrite concentrations, and black circles are measured cell densities. We measured extracellular nitrate and nitrite concentrations with IC and cell densities with FC. C Measured durations of nitrite availability for the generalist growing in batch culture. We grew the generalist alone in 96-well microtiter plates under anoxic conditions with nitrate as the growth-limiting substrate. Open symbols are durations of nitrite availability at pH 6.5 and closed symbols are durations of nitrite availability at pH 7.5. Each symbol is an independent biological replicate.Full size imageTo routinely quantify the duration of nitrite availability, we grew the generalist alone with varying amounts of nitrate as the growth-limiting substrate. We then quantified the length of time from when the growth rate with nitrate was maximum to when the growth rate with nitrite was maximum. This cell density-based proxy measure is valid because the growth of the generalist is directly linked to the consumption of nitrate and nitrite (Fig. 3A, B). The cell density of the generalist was initially linearly correlated with nitrate consumption at both pH 6.5 (strong nitrite toxicity) (two-sided Pearson correlation test; r = −0.96, p = 1.5 × 10–8, n = 15) (Fig. 3A) and 7.5 (weak nitrite toxicity) (two-sided Pearson correlation test; r = −1.00, p = 2.2 × 10–16, n = 30) (Fig. 3B). After nitrate was depleted, the cell density of the generalist became linearly correlated with nitrite consumption at both pH 6.5 (strong nitrite toxicity) (two-sided Pearson correlation test; r = −0.97, p = 3 × 10–4, n = 7) (Fig. 3A) and 7.5 (weak nitrite toxicity) (two-sided Pearson correlation test; r = −0.97, p = 6.8 × 10–10, n = 16) (Fig. 3B). We further validated our cell density-based approach by testing for concordance with our IC-based direct measures of the duration of nitrite availability. We observed a significant positive and linear relationship between the cell density- and IC-based measures (two-sided Pearson correlation test; r = 0.999, p = 0.023, n = 3) (linear regression model; slope = 1.19, intercept = −2.31, r2 = 0.99) (Supplementary Fig. S2), which further validates our cell density-based approach to routinely estimate the duration of nitrite availability.Using our cell density-based approach, we found that the duration of nitrite availability was significantly longer at pH 6.5 (strong nitrite toxicity) than at 7.5 (weak nitrite toxicity) regardless of the initial nitrate concentration (two-sample two-sided t-tests; Holm-adjusted p  0.92, Holm-adjusted p  0.6), and thus followed model predictions (Fig. 4A). However, when the specialist was initially rare (measured initial log rS/Gs of –3.19, –2.65, and –0.88), the relative abundances of the specialist continuously decreased between the third and twelfth transfers (Mann–Kendall trend tests; tau = –0.61 to –0.89, p  0 were dominated by phenotype C (dominant ancestral phenotype with a long time delay between nitrate and nitrite consumption), while generalist isolates from co-cultures with initial rS/Gs  More

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    Recent climate change has driven divergent hydrological shifts in high-latitude peatlands

    Hydrological changes in high-latitude peatlandsWe observed three hydrological pathways, i.e., drying, wetting, and fluctuating, for both peatland clusters, non-permafrost and permafrost peatlands (Fig. 2). Approximately 54% of the studied peatlands have shifted towards drier surface conditions since 1800 CE and more intensively since 1900 CE (Fig. 2a, d), which is in line with the post-LIA warming. The overall change point to drier conditions was dated to ca. 1950 CE for non-permafrost sites and ca. 1890 CE for the permafrost compiled group. Approximately 32% of the studied peatlands have shifted towards wetter conditions (Fig. 2b, e). The overall shifting point to wetter conditions was dated to ca. 1995 CE for non-permafrost peatlands and to ca. 1990 CE for permafrost peatlands. Wetting has been especially intensive since 1900 CE for non-permafrost peatlands and since 1950 CE for permafrost peatlands. Interestingly, the data showed that in permafrost peatlands a significant dry shift always preceded a wet shift (Fig. 2e). Approximately 14% of the studied peatlands indicated no clear trend, with fluctuating hydrological conditions (Fig. 2c, f).Non-permafrost peatlands generally showed spatially extensive drying across the northern high latitudes, apart from northeastern Canada, where a wetting trend was more frequently observed. Permafrost peatlands, however, were more variable, with some drying, some wetting, and no overall coherent regional pattern was visible (Fig.1a, b). It should be noted that peatlands synthesized here have undergone little or no direct human impact, i.e., their surface hydrology was not significantly affected by human disturbances such as drainage, when compared to, for example, central European peatlands discussed in Swindles et al. (2019)5. This implies that climate and/or local topographical forcing are the predominant hydrological drivers in this study. The dataset is to some extent biased as there are more non-permafrost records from northeastern Canada but more permafrost records from northern Sweden and this might result in regional overestimation to either wetting or drying trends. Nevertheless, the pattern of diverse timing of the hydrological shifts between the individual coring points (Fig. 2) indicates the variability in sensitivity of different regions/peatlands to climate changes.Potential links to climate change and permafrost dynamicsThe comparison of the reconstructed water table and climate data suggests that climate, especially summer temperature, has played an important role in shaping the peatland water table (Fig. 1c–f). The pattern detected here for non-permafrost peatlands, an extensive drying, is comparable to that observed for central European peatlands5. In addition to direct climate forcing, a recent acceleration of peat accumulation might partly explain the drying trend by disconnecting the peatland surface from the water table17. However, for northeastern Canada a wetting trend has been observed more often, possibly regulated by the regional climate that shows clearly less warming in the focused period compared to other regions (Fig. 1c, d).Permafrost initiation in the past caused a peat surface uplift and is probably detected as a dry phase (Fig. 2d, e). Post-LIA warming-induced increase in evapotranspiration may have strengthened the surface drying which originally resulted from surface-uplift and probably mitigated the gradual wetting related to permafrost thawing11. The level of warming has varied among the regions. In some areas such as northeastern Canada temperature has increased less and, when combined with higher precipitation or higher effective moisture level, may have caused surface wetting in permafrost peatlands. This is a direct climate forcing rather than permafrost thawing, which is a consequence of climate warming, i.e., more indirect climate forcing. To date, it is yet challenging to estimate any one tipping point of warming that might trigger permafrost thawing, as the local conditions vary from bottom ground soil conditions to hydrology and vegetation. The consequent wetting or drying depends on evapotranspiration and ice richness etc., which further challenges the prediction of hydrological conditions of permafrost peatlands.The divergent three moisture patterns may occur in the same region and even in the same peatland, especially if the permafrost is present. This complex response pattern is well supported by the records from the Abisko region, Sweden, where replicated sampling was carried out, and captured different successional stages of local permafrost peatlands7,18. In contrast to permafrost peatlands, non-permafrost peatlands are more likely to experience a more consistent ecosystem response pattern19 as supported by the replicated records suggesting the same pattern happening simultaneously in several regions (Fig. 1a). The fluctuating pattern of many records reported here suggests that the past and recent climate has not yet caused a state change in hydrological conditions.Insights into carbon dynamics and future perspectiveGenerally, our results suggest that the recent climate warming has caused hydrological shifts in most high-latitude peatlands, highlighting its pronounced effect on shaping peatland moisture balance, and further on driving peatland C balance. It has been reported that a 1-cm water-table drawdown would increase 3.3–5.0 mg CO2 m−2 h−1 and decrease 2.2–3.6 mg CO2-eq m−2 h−1 (CH4) to the atmosphere, and the average sensitivity of CO2 and CH4 combined was 0.8–2.3 mg CO2-eq m−2 h−1 cm−1 according to a global scale analysis, including sites from high-latitudes3. However, it should be noted that the sensitivity of greenhouse gas fluxes to the magnitude of hydrological changes might vary among different regions and peatland types. It appears that most pan-Arctic peatlands are undergoing a drying trend, that may lead to a decreased C sink capacity3,19, if not compensated by increased C uptake from the atmosphere20.It is very likely that over the 21st century warming in high latitudes will continue to be more pronounced than the global average21. Precipitation is projected to increase, albeit with large regional variability. Also, extreme events with heavy rainfall and drought are becoming more frequent and intense22. It is estimated that about 20% of permafrost zone is experiencing accelerated and abrupt permafrost thaw that is likely causing wetting conditions4, while gradual permafrost thaw has been observed across the circumpolar regions23. Both an increase in precipitation and permafrost thaw might mitigate the drying pressure caused by warming and increased evapotranspiration. However, abrupt permafrost thaw in peatlands can result in a rapid (over years to decades) loss of C from the formerly frozen permafrost peat, causing these peatlands to be a net source of C to the atmosphere before post-thaw accumulation returns them to a net sink (centuries to millennia)12,13. The future C sink and source function of peatlands is a key element in contributing to climate change, but the observed divergent pathways of peatland hydrological successions further challenge the projections of high-latitude peatland C sink and source dynamics. Conversely, it clearly highlights the importance of climate forcing in peatland succession scenarios. Our study reveals that the response of high-latitude peatlands to changing climate conditions is complex. We detect variable ecohydrological trajectories, and in the future, these will determine the C sink capacity of northern peatlands. The observed patterns inevitably create challenges for the climate change modelling community. How to capture the highly heterogenic successional pathways of northern peatlands needs to be a key research focus. More

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    Development of a portable toolkit to diagnose coral thermal stress

    To assess coral holobiont health, we used the commercially available Urinalysis strips (Accutest URS-14 100 strips Urinalysis Reagent Test Paper; ca. $11–35 USD/ bottle) that are designed to detect disease markers in humans, potentially indicating diabetes, metabolic abnormalities, liver diseases, kidney function, and urinary tract infections. There are ten tests on each strip that provide an initial assessment of health using the following standardized markers: leukocytes, nitrite, urobilinogen, protein, pH, blood, specific gravity, ketone, bilirubin, and glucose. To apply this test to coral extracts, we used ambient and stressed nubbins in a comparative approach to identify trends in the data. We presumed that some of the tests are likely not applicable to corals, whereas others such as ketones and leukocytes, which target conserved animal pathways (see below) could prove useful. Samples from three different coral experiments (two bleaching experiments and one environmental survey) were used to assess the response and utility of the different tests on each strip. The first bleaching experiments was done in 2019 on two Hawaiian species: Montipora capitata (stress resistant) and Pocillopora acuta (stress sensitive); this research has been previously described in detail11,12. Briefly, three M. capitata colonies (different genotypes) were selected, with samples collected from each in triplicate at three timepoints (referred to as T1, T3, and T5) that span a period of prolonged thermal stress (16 days). The second bleaching experiment was done in 2021 and included nubbins from M. capitata, P. acuta, and P. compressa. These corals were maintained for 9 days under heat treatment or ambient conditions, with samples collected at the beginning and end of the experimental period from both conditions (see Methods). Finally, the third experiment was done in June 2021 on wild colonies of M. capitata, P. acuta, and P. compressa (Fig. 1A) from Kāneʻohe Bay, Oʻahu, Hawaiʻi (Fig. 1B) and analyzed to assess the extent of natural variability in the test strip results. It should be noted that the test strip results from each experiment are independent (i.e., analyzed separately to measure relative differences within the test population) due to differences in tissue freezing time, storage length, and handling, that affect the results.Figure 1Analysis of Hawaiian corals. (A) The three targeted species in Kāneʻohe Bay. Images created by D. Bhattacharya. (B) Sites of wild coral collection (marked by the yellow circles) in Kāneʻohe Bay in June 2021. Nubbins from two colonies (n = 3) of M. capitata were collected from six reefs: Reef 8, 9, Reef 13, Reef 27, Reef 41, and Reef 43 and from three sites near the Hawaiʻi Institute of Marine Biology (HIMB) on Coconut Island (Moku o Loʻe). This image was adapted from the Pacific Islands ocean observing system (https://www.pacioos.hawaii.edu/projects/coral/)33.Full size imagePortable device for test strip analysisTo facilitate field testing and allow accurate measurement of test strip results in the R, G, and B channels, a combination of 3D printing technology and computer vision was applied to the problem. A custom opaque phone holder was produced using 3D printing (Ultimaker Inc. [https://ultimaker.com]) to control light source quality and quantity during the procedure and for calculating test strip scores (Fig. 2A). This portable phone holder was designed to allow field personnel to conduct experiments and collect results in a convenient and user-friendly manner. Inside the black opaque phone holder, two LED diodes served as a controllable and consistent light source to eliminate noise introduced by any change in light levels (between or during) the test strip reactions, allowing for more accurate and consistent data collection19. Frames of the videos (taken using the smart phone positioned in the holder) were captured for different reagents according to the recommended reading time given by the user manual. For test strip RGB value measurement (Fig. 2B), an automated machine learning method, shown in Fig. 2C, was used as a replacement for traditional, manual methods. Our computer vision workflow, named TestStripDX, uses YOLOv418, which is one of the most mature, accurate, and popular computer vision models available, to isolate a target feature in an image and provide the metadata associated with the object (in this case, each test along the strip), such as position within the coordinates of a rectangular box. Sample pictures of strips were manually annotated and used for training the TestStripDX pipeline (Supplementary Data 1): i.e., these images were used to train a custom detector to identify the different reagent tests along a strip and thereafter, to provide the relevant RGB values for each test (Fig. 2C). Figure 2D shows the comparison between data collected using the manual (ImageJ) versus automated (TestStripDX) methods for a partial list of samples and reagent strips (data shown in Table S1). The very close association of the regression line (R2 = 0.996) with the artificial diagonal line validates the utility and accuracy of the computer vision method.Figure 2Portable instrument for test strip analysis. (A) The 3D-printed phone holder used to analyze the test strips. (B) Example test strip. (C) Flow chart for the training and application of the machine learning method (TestStripDX) used to analyze test strips. (D) Comparison of test strip colorimetric measurement values produced by TestStripDX and ImageJ, for a set of representative images (Table S1). The enforced diagonal matches very closely to the regression line.Full size imageCoral color score measurementsAs described above, color scores provide a proxy for coral health, and are generated by measuring the RGB channels of the bleached (unhealthy) and brown (healthy: i.e., pigmentation provided by the algal symbionts) areas of coral nubbins. For the CoralDX workflow, we trained a custom detector that can recognize coral nubbins, as well as red, green, and blue colored blocks (standards) which are used to normalize the R, G, and B channels in each image (see Supplementary Data 2). The images taken in this case were from a lab environment (Fig. 3A), but this approach could potentially be used in any location provided a background with a uniform color is used in the image. To achieve this goal, a background panel containing the red, blue, and green color blocks would be placed behind (smaller) coral nubbins to make the measurements. It is clear that for large colonies, this approach may prove challenging to apply but we expect that additional testing and modification to the method will allow us to design a better-suited tool for field use. To achieve our goal of automatically obtaining colorimetric measurements of coral nubbins, we needed to devise a method that provides YOLOv4 with areas that are not limited by the standard rectangular boxes used as input for this model. To accommodate irregular nubbin shapes, an additional step (training and testing steps are shown in Fig. 3B) was added to the automated method (Fig. 2C). Our approach uses computer vision-based edge detection to eliminate most of the background surrounding the edges of the coral nubbins, allowing for accurate quantification of the RGB values of the targeted piece of coral. After edge detection, we obtain a picture with a black background highlighting the coral shape as a “mask” (Fig. 3C; 2nd image from left). We then place the mask onto the original coral image, measuring non-zero R, G, and B values (Fig. 3C; 3rd and 4th images from left). This method is superior to selecting coral areas for manual analysis using tools such as the handsfree selection function in ImageJ, which are generally hard to manipulate, have low fault tolerance, and are time-consuming. The RGB values extracted from the coral nubbins and color blocks were investigated using principal component analysis (PCA) to generate Euclidean distances (color scores) among coral nubbins according to treatment, time point, and colony11,16. In Fig. 3D, the correlation between bleaching scores generated using CoralDX and ImageJ for M. capitata and P. acuta are presented for a representative set of nubbins cultured under ambient or thermal stress conditions in the 2019 bleaching experiment (Tables S2, S3). As is apparent, the regression lines show strong correlations (R2 = 0.968 for M. capitata and R2 = 0.991 for P. acuta), supporting the utility of the automated method. The data in both cases are very closely associated with the artificial diagonal line shown in the images, substantiating the strong positive correlation between the scores from the two approaches. The small differences in score values between the methods is primarily explained by difficulties in cropping the edges of coral nubbins that are heavily bleached; the contrast between the coral nubbin and the white background is lessened, creating discrepancies between the nubbin edges identified by CoralDX and ImageJ. This issue can be addressed by testing different color backgrounds to find the optimal set-up. Another potential contributing factor is the differences in the area selected for the color blocks between manual (ImageJ) versus automated methods, although this might only have a minor effect on the results. The CoralDX workflow is not computationally intensive and easily portable to other platforms, such as personal computers and smart phones, allowing for easy deployment in the field.Figure 3Analysis of coral color scores. (A) Example image of M. capitata coral nubbins used for automated color score analysis, with target areas marked with the black (coral nubbins) and yellow (color standards) boxes. The nubbin on the far right is used to demonstrate the masking procedure. (B) Flow chart for the training and application of the machine learning method (CoralDX) used to analyze coral color scores. (C) Example of image processing for one M. capitata coral nubbin showing (from left to right) the original, masked, segmented, and masked RGB nubbin, with the final (right) image used for color score measurements. (D) Comparison of color score values produced by CoralDX and ImageJ, for a set of representative coral nubbins from the 2019 bleaching experiment (Tables S2, S3). The enforced diagonal matches very closely to the regression line in both analyses.Full size imageTest strip resultsArmed with these new tools, we generated the test strip data for different coral samples, where larger “relative enzymatic activity” (REA, measured using the RGB values) values indicate increased reactivity (i.e., increased levels of products targeted by the test). The Accutest URS-14 100 strips test for ketones (using the sodium nitroprusside reaction) measures acetoacetate and assumes the presence of β-hydroxybutyrate and acetone. The former (β-hydroxybutyrate) acts as a signal to regulate metabolism and maintain energy homeostasis during nutrient deprivation. In this process, β-hydroxybutyrate is converted to acetoacetate. Ketone bodies are transported into tissues and converted into acetyl-CoA by thiolases, which then enters the TCA cycle and is oxidized in the mitochondria for energy. Bleaching in corals which are incapable of obtaining adequate energy stores through heterotrophy results in diminished growth rates, degraded reproductive capacity, amplified susceptibility to disease, and elevated mortality rates for the entire colony20. Although ketosis has not been explored in cnidarians, transcriptomic data generated from the M. capitata samples measured in this study12 demonstrate expression of the KEGG pathway for degradation of ketone bodies (Fig. S1). The combination of time-point and treatment (field, T1-AT, T1-HT, T3-HT, T5-HT) was the most significant factor impacting the ketone REA scores (p-value = 0.010) (see details of the PERMANOVA analysis in the “Methods” section). Given this framework, we find that the M. capitata samples remain steady throughout the bleaching period, except for a decrease in enzymatic activity at T3-HT (Fig. 4A). This result is supported by the transcriptomic data, which shows this pathway to be uniformly expressed at all timepoints, except T3-HT, when acetyl-CoA C-acetyltransferase is up-regulated in comparison to T1-HT (fold change [FC] = 1.52) and down-regulated at T5-HT (FC = − 1.84) (Table S4). A possible explanation for this result is that at T3-HT, when the first evidence of bleaching was present, the photosynthetic rate of the symbiotic algae was elevated due to the thermal stress, resulting in greater energy production and a decrease in the abundance of ketone bodies within the coral, but without sufficient stress to cause significant bleaching. During this time, acetyl-CoA C-acetyltransferase enzymatic activity favored the production of acetoacetyl-CoA. However, as dysbiosis continued and the corals no longer had access to the photosynthetic products provided by the symbionts, they produced more acetoacetate and ketosis was detected by the test strips. This response occurs despite the observation that M. capitata can persist heterotrophically and meet much of its energy needs in the absence of algal symbionts21. Interestingly, the three M. capitata field samples show similar amounts of ketone bodies to lab stressed corals, suggesting the presence of stressors in the natural environment.Figure 4Test strip results from the 2019 bleaching experiment. (A) Ketone test strip results for M. capitata, showing genotype-specific (see legend) differences in response. (B) Leukocytes test strip results for M. capitata, showing genotype-specific (see legend) differences in response. These are standard box plots, with the boxes representing the first (Q1) to third (Q3) quartiles. The lines in the boxes are the median (Q2) values and lines (“whiskers”) extending beyond the boxes are the minimum and maximum values, excluding outliers. (C) PCA of the ketone and leukocytes test strip data for the field, ambient, and T1-HT, T3-HT, and T5-HT timepoints.Full size imageThe leukocyte test measures the activity of leukocyte esterase (presence of white blood cells) and other signs of infection in human subjects. This test putatively assesses the coral innate immunity response, which includes the same phases in response to infection and loss of tissue integrity as other invertebrates: recognition, signaling, and effector response22. Corals contain multiple types of immune cells, such as amoebocytes and fibroblasts23. Amoebocytes are amoeboid cells residing in the mesoglea that remove necrotic tissue, encapsulate foreign particles, and generally display phagocytic activity to aid in organism defense against pathogens, which is the cnidarian principal mechanism of immunity24. Amoebocytes can be melanin-containing, agranular, or granular based cells, depending on the signaling pathway22. M. capitata shows an overall increase in enzymatic activity at T1-HT, signaling a heightened immune response (Fig. 4B). This relatively higher level of enzymatic activity decreases at T3 and T5. The field samples show levels that are comparable to the T3-HT and T5-HT thermal stress acclimated colonies and the T1 ambient (Amb) colonies. Again, a combination of time-point and treatment was the most significant factor impacting the leukocyte REA scores (p-value = 0.001). Additional research needs to be done to understand the cause of this response. Nonetheless, the results are consistent with the widely accepted hypothesis that M. capitata adapts well to bleaching conditions12. PCA of the M. capitata test strip results shows a clear separation of the T1-HT coral data from the T3-HT and T5-HT values, with the ambient and field samples intermixed among the latter two timepoints (Fig. 4C). This result again highlights the initial robust response to stress by M. capitata followed by acclimation to the heat treatment that is reflected in the field samples.A noteworthy aspect of the test strip results is the divergence in response to thermal stress among different colonies. This result has also been found for coral metabolomic data11. As described above, each holobiont integrates a complex set of biotic interactions between the host animal and microbiome, explaining the high variation in ketone and leukocytes test results, often between replicate nubbins from one colony and more frequently, between different colonies (Fig. 4A). Existing data using omics methods demonstrate that the stress response of the coral holobiont varies from colony to colony15. The metabolome is controlled by the coral animal genotype, microbial consortium, and environmental conditions, among other factors, and can fluctuate greatly based on individual metabolite turnover rates and the timing of sampling25,26. Therefore, accounting for natural variation in the stress response phenotype and its importance for effective testing methods is a crucial aspect of our work. Our results demonstrate that broad population level sampling (dozens to 100 s of colonies/genotypes) is likely needed to account for the inherent genetic and metabolic variation present in wild coral populations.We also did a more limited analysis of coral stress responses using the ketone and leukocyte test strips with three species (M. capitata, P. acuta, P. compressa) in a 2021 bleaching experiment in which we sampled multiple coral genotypes at time 0 and after 9 days of heat treatment (3ºC increase from ambient; see Methods). These results are based on analysis of 8–9 different coral genotypes (summarized in Fig. 5). Interpreted in the same way as described above, we see that there is substantial genotype-based variation in the stress response. Nonetheless, consistent with the 2019 data, M. capitata shows evidence of a thermal stress response in the ketone and leukocytes tests (Fig. 5A, B). P. acuta shows a more limited response, whereas P. compressa appears to have fully acclimated to the stress regime with lowered reactivity at the end of the experiment. Species identity was the most significant factor impacting the leukocyte and ketone REA scores (p-value = 0.002 and 0.033, respectively), but a combination of species and treatment (AT vs. HT) was found to be significant for leukocytes (p-value = 0.026). PCA of the M. capitata test results shows separation between the ambient samples and some of the high temperature treated samples along PC1; both the ketone and leukocytes tests contribute to the spread of samples along PC1. This reinforces the conclusion that there is evidence for a thermal stress response in the ketone and leukocytes tests of M. capitata however, the significant genotypic variability (particularly apparent when compared with Fig. 4) obscures the differences between the conditions for some of the samples. PCA of the P. acuta and P. compressa test results mirrors our conclusion that the ketone and leukocytes tests in these species show a limited response to stress, with no separation between the samples from the different conditions.Figure 5Test strip results from the 2021 bleaching experiment for three Hawaiian coral species. (A) Ketone test strip results for M. capitata, P. acuta, and P. compressa showing genotype-specific variation in response under the ambient (Amb) and high temperature (HT) treatments. (B) Leukocytes test strip results for M. capitata, P. acuta, and P. compressa showing genotype-specific variation in response under the ambient and high temperature (HT) treatments. These are standard box plots, with the boxes representing the first (Q1) to third (Q3) quartiles. The lines in the boxes are the median (Q2) values and lines (“whiskers”) extending beyond the boxes are the minimum and maximum values, excluding outliers. (C) PCA of the ketone and leukocytes test strip data for the Amb and HT treatments for the three Hawaiian coral species.Full size imageAnalysis of wild populationsTo assess natural variation, we collected apparently healthy M. capitata, P. acuta, and P. compressa nubbins (3 replicate nubbins per colony) from six reefs in Kāneʻohe Bay and from three sites near the Hawaiʻi Institute of Marine Biology on Coconut Island (Moku o Loʻe) (see Fig. 1) and analyzed these tissue extracts using the ketone and leukocytes tests. This analysis shows wide variation in the results with some interesting exceptions. Species identity was the most significant factor impacting the leukocytes and ketone REA scores (p-value = 0.002 and 0.001, respectively), but for leukocytes, colony identity, regardless of species, was also found to be a significant factor (p-value = 0.040). The M. capitata ketone test results are consistent among different reefs and within the same colony with the exception of some colonies (e.g., Colony 8 from Reef 9 and Colony 16 from Reef 43) that show wide intra-colony variation (Fig. 6A). Most of the ketone data for M. capitata fall between REAs of 10–20. In contrast, P. acuta shows more variation in the wild populations for the ketone test, suggesting that many of these coral colonies live under stressful conditions in the field (Fig. 6B). A similar situation to M. capitata, in terms of REAs, holds for the ketone test of P. compressa colonies that show more limited variation (Fig. 6C). The leukocytes test shows high variation for M. capitata (Fig. 6D), P. acuta (Fig. 6E), and P. compressa (Fig. 6F) colonies. These results again point out the complex nature of genome-environment interaction with respect to metabolic syndromes, both at the colony level and among different regions (replicates) of the same colony. For example, P. compressa Colonies 13–15 from Reef 9 show little to no intra-colony variation for the ketone test, yet another colony from this reef (Colony 16) shows high variation among replicates (Fig. 6C). In contrast, P. compressa Colonies 13–15 are far more variable when using the leukocytes test (Fig. 6F). On the basis of the more predictable lab-based results reported above, we interpret these “noisy” field data as evidence of the immense variation in the stress phenome of wild coral populations. Overall, the field results indicate that a starting set of test strip values, followed by repeated field sampling over time of wild colonies may be needed for accurate stress diagnosis, rather than the one-time measurement approach used here. Clearly, more work is needed with wild colony analysis, particularly under varying degrees of thermal stress and apparent bleaching, to fully realize the potential of the technique we present.Figure 6Test strip results from analysis of the 2021 collection of three Hawaiian coral species from the wild. (A and D) Ketone and leukocytes test strip results, respectively, for M. capitata showing intraindividual variation and among the different reefs (see legend) that were sampled (Fig. 1B). (B and E) Ketone and leukocytes test strip results, respectively, for P. acuta showing intraindividual variation and among the different reefs that were sampled. (C and F) Ketone and leukocytes test strip results, respectively, for P. compressa showing intraindividual variation and among the different reefs (see legend) that were sampled. These are standard box plots, with the boxes representing the first (Q1) to third (Q3) quartiles. The lines in the boxes are the median (Q2) values and lines (“whiskers”) extending beyond the boxes are the minimum and maximum values, excluding outliers.Full size imageAnalysis of transcriptomic dataTo identify pathways that may support the M. capitata leukocytes test strip results, which showed the most response in terms of change in REA at T1-HT (Fig. 4B), we analyzed existing transcriptomic (RNA-seq) data derived from the same coral nubbins. The RNA-seq and metabolomic data from these samples have been previously analyzed11,12. Here we searched for co-expression modules that contain genes that are up-regulated at the start of the thermal stress regime (T1-HT) when compared to the ambient treatment. It is at this timepoint that we find a strong cross-reaction with the leukocytes test, followed by loss of cross-reactivity at T3-HT and T5-HT (back down to T1-Amb levels), putatively indicating acclimation (Fig. 4B). As described above, the wound healing response in corals is complex and the (Urinalysis) leukocytes results need to be interpreted as a syndrome involving multiple pathways of stress and immune response. With these considerations in mind, we identified a module (Module 2; see Williams et al.12) of up-regulated genes that contains several markers associated with the coral stress response (Fig. 7). These include a tumor necrosis factor-activated receptor (TNFR)-Cys domain-containing protein (fold-change [FC] = 1.12) that is a well-known mediator of apoptosis and cell death that is functionally conserved in corals. Some members of the TNF family are associated with bleaching27. The most highly up-regulated gene in this module is C-type lysozyme 2 (FC = 2.42) that provides an anti-microbial function (e.g., digestion of peptidoglycan), and is likely expressed as a result of stress-induced dysbiosis in M. capitata. Other markers of stress that are up-regulated in Module 2 include E3 ubiquitin-protein ligase (FC = 1.03) involved in protein degradation, two protein disulfide-isomerase (FCs = 1.32, 1.09) involved in cellular defense against protein misfolding via chaperone activity28, and a metalloproteinase inhibitor 3 (FC = 1.42) which likely functions as a physiological anti-inflammatory molecule29. These data, although not directly substantiating the leukocytes test strip results, provide evidence that the wound healing and immune response pathways were up-regulated in Module 2 at T1-HT (albeit weakly, due to the stress resilience of M. capitata) as suggested by Fig. 4B.Figure 7Gene co-expression analysis. Module 2 representing significantly up-regulated genes in M. capitata from T1-HT in the 2019 differential gene expression analysis12. This module is enriched in genes involved in the wound healing and immune response. The legend for level of up-regulation is shown. Putative gene annotations are also shown.Full size image More

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    Assessing the expansion of the Cambrian Agronomic Revolution into fan-delta environments

    Erwin, D. H. & Tweedt, S. Ecological drivers of the Ediacaran-Cambrian diversification of Metazoa. Evol. Ecol. 26, 417–433 (2012).Article 

    Google Scholar 
    Laflamme, M., Darroch, S. A., Tweedt, S. M., Peterson, K. J. & Erwin, D. H. The end of the Ediacara biota: Extinction, biotic replacement, or Cheshire Cat?. Gondwana Res. 23, 558–573 (2013).ADS 
    Article 

    Google Scholar 
    Mángano, M. G. & Buatois, L. A. Decoupling of body-plan diversification and ecological structuring during the Ediacaran-Cambrian transition: Evolutionary and geobiological feedbacks. Proc. R. Soc. B-Biol. Sci. 281, 20140038 (2014).Article 

    Google Scholar 
    Mángano, M. G. & Buatois, L. A. The Cambrian revolutions: Trace-fossil record, timing, links and geobiological impact. Earth-Sci. Rev. 173, 96–108 (2017).ADS 
    Article 

    Google Scholar 
    Mángano, M. G. & Buatois, L. A. The rise and early evolution of animals: Where do we stand from a trace-fossil perspective?. Interface Focus 10, 20190103 (2020).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Darroch, S. A. et al. Biotic replacement and mass extinction of the Ediacara biota. Proc. R. Soc. B 282, 20151003 (2015).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Darroch, S. A., Smith, E. F., Laflamme, M. & Erwin, D. H. Ediacaran extinction and Cambrian explosion. Trends Ecol. Evol. 33, 653–663 (2018).PubMed 
    Article 

    Google Scholar 
    Schiffbauer, J. D. et al. The latest Ediacaran Wormworld fauna: Setting the ecological stage for the Cambrian explosion. GSA Today 26, 4–11 (2016).Article 

    Google Scholar 
    Zamora, S., Deline, B., Javier Álvaro, J. & Rahman, I. A. The Cambrian Substrate Revolution and the early evolution of attachment in suspension-feeding echinoderms. Earth-Sci. Rev. 171, 478–491 (2017).ADS 
    Article 

    Google Scholar 
    Hantsoo, K. G., Kaufman, A. J., Cui, H., Plummer, R. E. & Narbonne, G. M. Effects of bioturbation on carbon and sulfur cycling across the Ediacaran-Cambrian transition at the GSSP in Newfoundland, Canada. Can. J. Earth Sci. 55, 1240–1252 (2018).ADS 
    CAS 
    Article 

    Google Scholar 
    Boyle, R. A., Dahl, T. W., Bjerrum, C. J. & Canfield, D. E. Bioturbation and directionality in Earth’s carbon isotope record across the Neoproterozoic-Cambrian transition. Geobiology 16, 252–278 (2018).CAS 
    PubMed 
    Article 

    Google Scholar 
    van de Velde, S., Mills, B. J., Meysman, F. J., Lenton, T. M. & Poulton, S. W. Early Palaeozoic ocean anoxia and global warming driven by the evolution of shallow burrowing. Nat. Commun. 9, 2554 (2018).ADS 
    PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Gougeon, R. C., Mangano, M. G., Buatois, L. A., Narbonne, G. M. & Laing, B. A. Early Cambrian origin of the shelf sediment mixed layer. Nat. Commun. 9, 1909 (2018).ADS 
    PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    Seilacher, A. & Pflüger, F. In Biostabilization of Sediments (eds. Krumbein W. E., Peterson D. M., & Stal L. J.) 97–105 (Bibliotheks und Informationsystem der Carl von Ossietzky Universität, 1994).Seilacher, A. Biomat-related lifestyles in the Precambrian. Palaios 14, 86–93 (1999).ADS 
    Article 

    Google Scholar 
    Buatois, L. A. et al. Quantifying ecospace utilization and ecosystem engineering during the early Phanerozoic: The role of bioturbation and bioerosion. Sci. Adv. 6, eabb0618 (2020).ADS 
    CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    Hagadorn, J. W. & Bottjer, D. J. Restriction of a late Neoproterozoic biotope; suspect-microbial structures and trace fossils at the Vendian-Cambrian transition. Palaios 14, 73–85 (1999).ADS 
    Article 

    Google Scholar 
    Buatois, L. A. & Mangano, M. G. Early colonization of the deep sea: Ichnologic evidence of deep-marine benthic ecology from the Early Cambrian of northwest Argentina. Palaios 18, 572–581 (2003).ADS 
    Article 

    Google Scholar 
    Clausen, S., Álvaro, J. J. & Zamora, S. Replacement of benthic communities in two Neoproterozoic-Cambrian subtropical-to-temperate rift basins, High Atlas and Anti-Atlas, Morocco. J. Afr. Earth Sci. 98, 72–93 (2014).ADS 
    Article 

    Google Scholar 
    Mángano, M. G. & Buatois, L. A. In The Trace-Fossil Record of Major Evolutionary Events: Volume 1: Precambrian and Paleozoic (eds. Mángano M. G. & Buatois L. A.) 73–126 (Springer Netherlands, 2016).Bayet-Goll, A., Buatois, L. A., Mangano, M. G. & Daraei, M. The interplay of environmental constraints and bioturbation on matground development along the marine depositional profile during the Ordovician Radiation. Geobiology 20, 33–270 (2022).Article 
    CAS 

    Google Scholar 
    Bayet-Goll, A., Daraei, M., Geyer, G., Bahrami, N. & Bagheri, F. Environmental constraints on the distribution of matground and mixground ecosystems across the Cambrian Series 2–Miaolingian boundary interval in Iran: A case study for the central sector of northern Gondwana. J. Afr. Earth Sci. 176, 104120 (2021).Article 

    Google Scholar 
    Minter, N. J. et al. In The Trace-Fossil Record of Major Evolutionary Events: Volume 1: Precambrian and Paleozoic (eds. Mángano M. G. & Buatois L. A.) 157–204 (Springer Netherlands, 2016).Minter, N. J. et al. Early bursts of diversification defined the faunal colonization of land. Nat. Ecol. Evol. 1, 0175 (2017).Article 

    Google Scholar 
    Nemec, W. & Steel, R. J. In Fan Deltas: sedimentology and tectonic settings (eds. Nemec W. & Steel R. J.) 3–13 (Blackie and Son, 1988).Postma, G. An analysis of the variation in delta architecture. Terra Nova 2, 124–130 (1990).ADS 
    Article 

    Google Scholar 
    Prior, D. B. & Bornhold, B. D. Submarine sedimentation on a developing Holocene fan delta. Sedimentology 36, 1053–1076 (1989).ADS 
    Article 

    Google Scholar 
    Piper, D. J. W., Kontopoulos, N., Anagnostou, C., Chronis, G. & Panagos, A. G. Modern fan deltas in the western Gulf of Corinth, Greece. Geo-Mar. Lett. 10, 5–12 (1990).ADS 
    Article 

    Google Scholar 
    Rasmussen, H. Nearshore and alluvial facies in the Sant Llorenç del Munt depositional system: Recognition and development. Sediment. Geol. 138, 71–98 (2000).ADS 
    Article 

    Google Scholar 
    Steel, R., Rasmussen, H., Eide, S., Neuman, B. & Siggerud, E. Anatomy of high-sediment supply, transgressive tracts in the Vilomara composite sequence, Sant LlorencË del Munt, Ebro Basin, NE Spain. Sediment. Geol. 138, 125–142 (2000).ADS 
    Article 

    Google Scholar 
    Zavala, C. et al. Deltas: A new classification expanding Bates’s concepts. J. Palaeogeogr. 10, 23 (2021).ADS 
    Article 

    Google Scholar 
    Ekdale, A. A. & Lewis, D. W. Trace fossils and paleoenvironmental control of ichnofacies in a late Quaternary gravel and loess fan delta complex, New Zealand. Palaeogeogr. Palaeoclimatol. Palaeoecol. 81, 253–279 (1991).Article 

    Google Scholar 
    Buatois, L. A. & Mángano, M. G. Ichnology: Organism-substrate Interactions in Space and Time (Cambridge University Press, 2011).Book 

    Google Scholar 
    Hovikoski, J., Uchman, A., Alsen, P. & Ineson, J. Ichnological and sedimentological characteristics of submarine fan-delta deposits in a half-graben, Lower Cretaceous Palnatokes Bjerg Formation, NE Greenland. Ichnos 26, 28–57 (2019).Article 

    Google Scholar 
    Sendra, J., Reolid, M. & Reolid, J. Palaeoenvironmental interpretation of the Pliocene fan-delta system of the Vera Basin (SE Spain): Fossil assemblages, ichnology and taphonomy. Palaeoworld 29, 769–788 (2020).Article 

    Google Scholar 
    Kreis, L. K. et al. Lower Paleozoic map series: Saskatchewan. Miscellaneous Report 2004–8 (CD-ROM) (Saskatchewan Industry and Resources, 2004).
    Google Scholar 
    Marsh, A. & Love, M. In Saskatchewan Ministry of the Economy, Saskatchewan Geological Survey, Saskatchewan Geological Survey Vol. Open File 2014-1, set of 156 maps (2014).Sawatzky, H. B., Agarwal, R. G. & Wilson, W. Helium prospects of southwest Saskatchewan. 26 (Saskatchewan Department of Mineral Resources, 1960).Fyson, W. K. Deadwood and Winnipeg stratigraphy in southwestern Saskatchewan. Report 64, 37 (Saskatchewan Department of Mineral Resources, 1961).Kent, D. M. Paleotectonic controls on sedimentation in northern Williston Basin area, Saskatchewan. AAPG Bull. 67, 1345–1345 (1983).
    Google Scholar 
    Kent, D. M. & Haidl, F. M. The distribution of Ashern and Winnipegosis strata (Middle Devonian) on the Swift Current Platform, southern Saskatchewan. Summary of Investigations, Miscellaneous Report 93-4, 201–206 (Saskatchewan Geological Survey, Saskatchewan Energy and Mines, 1993).MacEachern, J. A., Zaitlin, B. A. & Pemberton, S. G. A sharp-based sandstone of the Viking Formation, Joffre Field, Alberta, Canada; criteria for recognition of transgressively incised shoreface complexes. J. Sediment. Res. 69, 876–892 (1999).ADS 
    Article 

    Google Scholar 
    Pemberton, S. G., Frey, R. W. & Bromley, R. G. The ichnotaxonomy of Conostichus and other plug-shaped ichnofossils. Can. J. Earth Sci. 25, 866–892 (1988).ADS 
    Article 

    Google Scholar 
    Hall, J. & Whitfield, R. P. Paleontology. In US Geol. Expl. 40th Par. Rept. 4, 197–302 (1877).Walcott, C. D. Cambrian and Lower Ozarkian trilobites. Smithson. Misc. Coll. 75, 53–60 (1924).
    Google Scholar 
    Meek, F. B. Preliminary paleontological report, consisting of lists and descriptions of fossils, with remarks on the ages of the rocks in which they were found. In U. S. Geol. Surv. Terr. 6th Ann. Rept., 429–518 (1873).Walcott, C. D. Cambrian geology and paleontology of Cambrian trilobites. Smithson. Misc. Coll. 64, 157–258 (1916).
    Google Scholar 
    Harding, S. C. & Ekdale, A. A. Trace fossils and glauconitic pellets provide insight into Cambrian siliciclastic marine environments. Palaios 33, 256–265 (2018).ADS 
    Article 

    Google Scholar 
    Shillito, A. P. & Davies, N. S. The Tumblagooda Sandstone revisited: Exceptionally abundant trace fossils and geological outcrop provide a window onto Palaeozoic littoral habitats before invertebrate terrestrialization. Geol. Mag. 157, 1939–1970 (2020).ADS 
    Article 

    Google Scholar 
    Shillito, A. P. & Davies, N. S. Archetypally Siluro-Devonian ichnofauna in the Cowie Formation, Scotland: Implications for the myriapod fossil record and Highland Boundary Fault Movement. Proc. Geol. Assoc. 128, 815–828 (2017).Article 

    Google Scholar 
    Buatois, L. A. et al. The invasion of the land in deep time: integrating Paleozoic records of paleobiology, ichnology, sedimentology, and geomorphology. Integr. Comp. Biol. 0, 1–35. https://doi.org/10.1093/icb/icac059 (2022).Davies, N. S. & Gibling, M. R. Paleozoic vegetation and the Siluro-Devonian rise of fluvial lateral accretion sets. Geology 38, 51–54 (2010).ADS 
    Article 

    Google Scholar 
    McMahon, W. J. & Davies, N. S. Evolution of alluvial mudrock forced by early land plants. Science 359, 1022–1024 (2018).ADS 
    CAS 
    PubMed 
    Article 

    Google Scholar 
    Fedo, C. M. & Cooper, J. D. Braided fluvial to marine transition; the basal Lower Cambrian Wood Canyon Formation, southern Marble Mountains, Mojave Desert, California. J. Sediment. Res. 60, 220–234 (1990).
    Google Scholar 
    Eyre, B. Early Cambrian alluvial fan-deltas in the Georgina Basin, Australia. Aust. J. Earth Sci. 41, 27–36 (1994).ADS 
    Article 

    Google Scholar 
    MacNaughton, R. B., Dalrymple, R. & Narbonne, G. M. Early Cambrian braid-delta deposits, MacKenzie Mountains, north-western Canada. Sedimentology 44, 587–609 (1997).ADS 
    Article 

    Google Scholar 
    Muhlbauer, J. G. & Fedo, C. M. Architecture of a river-dominated, wave- and tide-influenced, pre-vegetation braid delta: Cambrian middle member of the Wood Canyon Formation, southern Marble Mountains, California, U.S.A. J. Sediment. Res. 90, 1011–1036 (2020).ADS 
    Article 

    Google Scholar 
    McMahon, W. J., Davies, N. S. & Went, D. J. Negligible microbial matground influence on pre-vegetation river functioning: Evidence from the Ediacaran-Lower Cambrian Series Rouge, France. Precambrian Res. 292, 13–34 (2017).ADS 
    CAS 
    Article 

    Google Scholar 
    Mikuláš, R. Trace fossils from the Paseky Shale (Early Cambrian, Czech Republic). J. Czech Geol. Soc. 40, 37–44 (1995).
    Google Scholar 
    MacNaughton, R. B. & Narbonne, G. M. Evolution and ecology of Neoproterozoic-Lower Cambrian trace fossils, NW Canada. Palaios 14, 97–115 (1999).ADS 
    Article 

    Google Scholar 
    Buatois, L. A. et al. Colonization of brackish-water systems through time: Evidence from the trace-fossil record. Palaios 20, 321–347 (2005).ADS 
    Article 

    Google Scholar 
    Hofmann, R., Mángano, M. G., Elicki, O. & Shinaq, R. Paleoecologic and biostratigraphic significance of trace fossils from shallow- to marginal-marine environments from the Middle Cambrian (Stage 5) of Jordan. J. Paleontol. 86, 931–955 (2012).Article 

    Google Scholar 
    Mángano, M. G., Buatois, L. A., Hofmann, R., Elicki, O. & Shinaq, R. Exploring the aftermath of the Cambrian explosion: The evolutionary significance of marginal- to shallow-marine ichnofaunas of Jordan. Palaeogeogr. Palaeoclimatol. Palaeoecol. 374, 1–15 (2013).Article 

    Google Scholar 
    Mángano, M. G. et al. Were all trilobites fully marine? Trilobite expansion into brackish water during the early Palaeozoic. Proc. R. Soc. Lond. B Biol. Sci. 288, 20202263 (2021).
    Google Scholar 
    Siggerud, E. I. H. & Steel, R. J. Architecture and trace-fossil characteristics of a 10000–20000 Year, fluvial-to-marine sequence, SE Ebro Basin, Spain. J. Sediment. Res. 69, 365–383 (1999).ADS 
    Article 

    Google Scholar 
    Lockley, M. G., Rindsberg, A. K. & Zeiler, R. M. The paleoenvironmental significance of the nearshore Curvolithus ichnofacies. Palaios 2, 255–262 (1987).ADS 
    Article 

    Google Scholar 
    Folk, R. L. Petrology of Sedimentary Rocks (Hemphill Publishing Company, 1980).
    Google Scholar 
    Wentworth, C. K. A scale grade and class terms for clastic sediments. J. Geol. 30, 377–392 (1922).ADS 
    Article 

    Google Scholar 
    Pettijohn, F. J., Potter, P. E. & Siever, R. Sand and Sandstone 2nd edn. (Springer, 1987).Book 

    Google Scholar 
    Ingram, R. L. Terminology for the thickness of stratification and parting units in sedimentary rocks. Geol. Soc. Am. Bull. 65, 937–938 (1954).ADS 
    Article 

    Google Scholar 
    Reineck, H.-E. Sedimentgefüge im Bereich der südliche Nordsee. Abh. Senckb. Naturforsch. Ges. 505, 1–138 (1963).
    Google Scholar  More