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    Exploring physicochemical and cytogenomic diversity of African cowpea and common bean

    1.Lewis, G. P. Legumes of the World (Royal Botanic Gardens, 2005).
    Google Scholar 
    2.The Legume Phylogeny Working Group (LPWG). A new subfamily classification of the Leguminosae based on a taxonomically comprehensive phylogeny. Taxon 66, 44–77 (2017).Article 

    Google Scholar 
    3.Yahara, T. et al. Global legume diversity assessment: Concepts, key indicators, and strategies. Taxon 62, 249–266 (2013).Article 

    Google Scholar 
    4.Odendo, M., Bationo, A. & Kimani, S. Socio-economic contribution of legumes to livelihoods in Sub-Saharan Africa. In Fighting Poverty in Sub-Saharan Africa: The Multiple Roles of Legumes in Integrated Soil Fertility Management (eds Bationo, A. et al.) 27–46 (Springer, 2011).Chapter 

    Google Scholar 
    5.Dakora, F. D. & Keya, S. O. Contribution of legume nitrogen fixation to sustainable agriculture in Sub-Saharan Africa. Soil Biol. Biochem. 29, 809–817 (1997).CAS 
    Article 

    Google Scholar 
    6.Ajeigde, H. A., Singh, B. B. & Osenj, T. O. Cowpea-cereal intercrop productivity in the Sudan savanna zone of Nigeria as affected by planting pattern, crop variety and pest management. Afr. Crop Sci. J. 13, 269–279 (2005).
    Google Scholar 
    7.Rahmanian, M., Batello, C. & Calles, T. Pulse Crops for Sustainable Farms in Sub-Saharan Africa (FAO, 2018).
    Google Scholar 
    8.Rawal, V. & Navarro, D. K. The Global Economy of Pulses (FAO, 2017).
    Google Scholar 
    9.Plants of the World Online. http://powo.science.kew.org (2020).10.Broughton, W. J. et al. Beans (Phaseolus spp.)—Model food legumes. Plant Soil 252, 55–128 (2003).CAS 
    Article 

    Google Scholar 
    11.Delgado-Salinas, A., Bibler, R. & Lavin, M. Phylogeny of the genus Phaseolus (Leguminosae): A recent diversification in an ancient landscape. Syst. Bot. 31, 779–791 (2006).Article 

    Google Scholar 
    12.Greenway, P. J. Origins of some East African food plants: Part V. East Afr. Agric. J. 11, 56–63 (1945).
    Google Scholar 
    13.Wortmann, C. S. & Allen, D. J. African Bean Production Environments: Their Definition, Characteristics and Constraints. Occasional Publication Series 11 (CIAT, 1994).
    Google Scholar 
    14.Maxted, N. et al. African Vigna: Systematic and Ecogeographic Studies (International Plant Genetic Resource Institute, 2004).
    Google Scholar 
    15.Singh, B. B. Cowpea: The Food Legume of the 21st Century (Crop Science Society of America Inc., 2014).Book 

    Google Scholar 
    16.Catarino, S. et al. Conservation priorities for African Vigna species: Unveiling Angola’s diversity hotspots. Glob. Ecol. Conserv. 25, e01415. https://doi.org/10.1016/j.gecco.2020.e01415 (2021).Article 

    Google Scholar 
    17.Vidigal, P., Romeiras, M. M. & Monteiro, F. Crops diversification and the role of orphan legumes to improve the Sub-Saharan Africa farming systems. In Sustainable Crop Production (ed. Hasanuzzaman, M.) (IntechOpen, 2019).
    Google Scholar 
    18.Maréchal, R. Etude taxonomique d’un groupe complexe d’espèces des genres Phaseolus et Vigna (Papilionaceae) sur la base de données morphologiques et polliniques, traitées par l’analyse informatique. Boissiera 28, 1–273 (1978).
    Google Scholar 
    19.Peksen, E., Peksen, A. & Gulumser, A. Leaf and stomata characteristics and tolerance of cowpea cultivars to drought stress based on drought tolerance indices under rainfed and irrigated conditions. Int. J. Curr. Microbiol. Appl. Sci. 3, 626–634 (2014).CAS 

    Google Scholar 
    20.Iqbal, A., Khalil, I. A., Ateeq, N. & Khan, M. S. Nutritional quality of important food legumes. Food Chem. 97, 331–335 (2006).CAS 
    Article 

    Google Scholar 
    21.African Orphan Crops Consortium. http://africanorphancrops.org/meet-the-crops/ (2021)22.Boukar, O. et al. Cowpea. In Grain Legumes (ed. de Ron, A. M.) 219–250 (Springer, 2015).Chapter 

    Google Scholar 
    23.Animasaun, D. A., Oyedeji, S., Azeez, Y. K., Mustapha, O. T. & Azeez, M. A. Genetic variability study among ten cultivars of cowpea (Vigna unguiculata L. Walp) using morpho-agronomic traits and nutritional composition. J. Agric. Sci. 10, 119–130 (2015).
    Google Scholar 
    24.Timko, M. P. & Singh, B. B. Cowpea, a multifunctional legume. In Plant Genetics and Genomics: Crops and Models Vol. 1 (eds Moore, P. H. & Ming, R.) 227–258 (Springer, 2008).
    Google Scholar 
    25.Wortmann, S. C., Kirkby, A. R., Eledu, A. C. & Allen, J. D. Atlas of Common Bean (Phaseolus vulgaris L.) Production in Africa (International Centre for Tropical Agriculture, 2004).
    Google Scholar 
    26.Guignard, M. S. et al. Genome size and ploidy influence angiosperm species’ biomass under nitrogen and phosphorus limitation. New Phytol. 210, 1195–1206 (2016).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    27.Sheidai, M. et al. Genetic diversity and genome size variability in Linum austriacum (Lineaceae) populations. Biochem. Syst. Ecol. 57, 20–26 (2014).CAS 
    Article 

    Google Scholar 
    28.Kron, P., Suda, J. & Husband, B. C. Applications of flow cytometry to evolutionary and population biology. Annu. Rev. Ecol. Evol. Syst. 38, 847–876 (2007).Article 

    Google Scholar 
    29.Wu, Y. Q. et al. Genetic analyses of Chinese Cynodon accessions by flow cytometry and AFLP markers. Crop Sci. 46, 917–926 (2016).Article 

    Google Scholar 
    30.Parida, A., Raina, S. N. & Narayan, R. K. J. Quantitative DNA variation between and within chromosome complements of Vigna species (Fabaceae). Genetica 82, 125–133 (1990).CAS 
    Article 

    Google Scholar 
    31.Nagl, W. & Treviranus, A. A flow cytometric analysis of the nuclear 2C DNA content in 17 Phaseolus species (53 genotypes). Bot. Acta 108, 403–406 (1995).CAS 
    Article 

    Google Scholar 
    32.Barow, M. & Meister, A. Endopolyploidy in seed plants is differently correlated to systematics, organ, life strategy and genome size. Plant Cell Environ. 26, 571–584 (2003).Article 

    Google Scholar 
    33.Lonardi, S. et al. The genome of cowpea (Vigna unguiculata [L.] Walp.). Plant J. 98, 767–782 (2019).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    34.The IUCN Red List of Threatened Species. Version 2020-2. https://www.iucnredlist.org/ (2020).35.Genesys. Plant Genetic Resources Accession. https://www.genesys-pgr.org/ (2021).36.Pope, G. V. & Polhill, R. M. Flora Zambesiaca, part 5 Vol. 3 (Royal Botanic Gardens, 2001).
    Google Scholar 
    37.Tomooka, N., Vaughan, D. A., Moss, H. & Maxted, N. The Asian Vigna: Genus Vigna Subgenus Ceratotropis Genetic Resources (Kluwer Academic Publishers, 2002).Book 

    Google Scholar 
    38.Debouck, D. G. Primary diversification of Phaseolus in the Americas: Three centers. Plant Genet. Resour. Newsl. 67, 2–8 (1986).
    Google Scholar 
    39.Plant Resources of Tropical Africa. https://www.prota4u.org/database/ (2021).40.Linder, H. P. The evolution of African plant diversity. Front. Ecol. Evol. 2, 38. https://doi.org/10.3389/fevo.2014.00038 (2014).Article 
    ADS 

    Google Scholar 
    41.Romeiras, M. M., Figueira, R., Duarte, M. C., Beja, P. & Darbyshire, I. Documenting biogeographical patterns of African timber species using herbarium records: A conservation perspective based on native trees from Angola. PLoS ONE 9, e103403. https://doi.org/10.1371/journal.pone.0103403 (2014).CAS 
    Article 
    PubMed 
    PubMed Central 
    ADS 

    Google Scholar 
    42.Catarino, S. et al. Spatial and temporal trends of burnt area in angola: Implications for natural vegetation and protected area management. Diversity 12, 307. https://doi.org/10.3390/d12080307 (2020).Article 

    Google Scholar 
    43.Catarino, S., Duarte, M. C., Costa, E., Carrero, P. G. & Romeiras, M. M. Conservation and sustainable use of the medicinal Leguminosae plants from Angola. PeerJ 7, e6736. https://doi.org/10.7717/peerj.6736 (2019).Article 
    PubMed 
    PubMed Central 

    Google Scholar 
    44.Romeiras, M. M. et al. IUCN Red List assessment of the Cape Verde endemic flora: Towards a global strategy for plant conservation in Macaronesia. Bot. J. Linn. Soc. 180, 413–425 (2016).Article 

    Google Scholar 
    45.Gomes, A. M. et al. Drought response of cowpea (Vigna unguiculata (L.) Walp.) landraces at leaf physiological and metabolite profile levels. Environ. Exp. Bot. 175, 104060. https://doi.org/10.1016/j.envexpbot.2020.104060 (2020).CAS 
    Article 

    Google Scholar 
    46.The International Institute of Tropical Agriculture (IITA). https://www.iita.org/ (2021)47.Fatokun, C. et al. Genetic diversity and population structure of a mini-core subset from the world cowpea (Vigna unguiculata (L.) Walp.) germplasm collection. Sci. Rep. 8, 16035. https://doi.org/10.1038/s41598-018-34555-9 (2018).CAS 
    Article 
    PubMed 
    PubMed Central 
    ADS 

    Google Scholar 
    48.Rocha, V., Duarte, M. C., Catarino, S., Duarte, I. & Romeiras, M. M. Cabo Verde’s Poaceae flora: A reservoir of crop wild relatives diversity for crop improvement. Front. Plant Sci. 12, 630217. https://doi.org/10.3389/fpls.2021.630217 (2021).Article 
    PubMed 
    PubMed Central 

    Google Scholar 
    49.Brilhante, M. et al. Tackling food insecurity in Cabo Verde Islands: The nutritional, agricultural and environmental values of the legume species. Foods 10, 206. https://doi.org/10.3390/foods10020206 (2021).Article 
    PubMed 
    PubMed Central 

    Google Scholar 
    50.Pasquet, R. S. Wild cowpea (Vigna unguiculata) evolution. In Advances in Legume Systematics 8: Legumes of Economic Importance (eds Pickersgill, B. & Lock, J. M.) 95–100 (Royal Botanic Gardens, 1996).
    Google Scholar 
    51.Di Bella, G. et al. Mineral composition of some varieties of beans from Mediterranean and Tropical areas. Int. J. Food Sci. Nutr. 67, 239–248 (2016).PubMed 
    Article 
    CAS 
    PubMed Central 

    Google Scholar 
    52.Gelin, J. R., Forster, S., Grafton, K. F., McClean, P. E. & Rojas-Cifuentes, G. A. Analysis of seed zinc and other minerals in a recombinant inbred population of navy bean (Phaseolus vulgaris L.). Crop Sci. 47, 1361–1366 (2007).CAS 
    Article 

    Google Scholar 
    53.Dakora, F. D. & Belane, A. K. Evaluation of protein and micronutrient levels in edible cowpea (Vigna unguiculata L. Walp) leaves and seeds. Front. Sustain. Food Syst. 3, 70. https://doi.org/10.3389/fsufs.2019.00070 (2019).Article 

    Google Scholar 
    54.Yeken, M. Z., Akpolat, H., Karaköy, T. & Çiftçi, V. Assessment of mineral content variations for biofortification of the bean seed. Int. J. Agric. Sci. 4, 261–269 (2018).
    Google Scholar 
    55.Gondwe, T. M., Alamu, E. O., Mdziniso, P. & Maziya-Dixon, B. Cowpea (Vigna unguiculata (L.) Walp) for food security: An evaluation of end-user traits of improved varieties in Swaziland. Sci. Rep. 9, 15991. https://doi.org/10.1038/s41598-019-52360-w (2019).CAS 
    Article 
    PubMed 
    PubMed Central 
    ADS 

    Google Scholar 
    56.Sperotto, R. A., Ricachenevsky, F. K., Williams, L. E., Vasconcelos, M. W. & Menguer, P. K. From soil to seed: Micronutrient movement into and within the plant. Front. Plant Sci. 5, 438. https://doi.org/10.3389/fpls.2014.00438 (2014).Article 
    PubMed 
    PubMed Central 

    Google Scholar 
    57.Maziya-Dixon, B., Kling, J. G., Menkir, A. & Dixon, A. Genetic variation in total carotene, iron, and zinc contents of maize and cassava genotypes. Food Nutr. Bull. 21, 419–422 (2000).Article 

    Google Scholar 
    58.Shewfelt, R. L. Sources of variation in the nutrient content of agricultural commodities from the farm to the consumer. J. Food Qual. 13, 37–54 (1990).Article 

    Google Scholar 
    59.World Health Organization. The World Health Report 2006: Working Together for Health. https://www.who.int/whr/2006/whr06_en.pdf?ua=1 (2006).60.Gödecke, T., Stein, A. J. & Qaim, M. The global burden of chronic and hidden hunger: Trends and determinants. Glob. Food Sec. 17, 21–29 (2018).Article 

    Google Scholar 
    61.Shankar, A. H. Mineral deficiencies. In Hunter’s Tropical Medicine and Emerging Infectious Diseases (eds Ryan, E. T. et al.) 1048–1054 (Elsevier, 2020).Chapter 

    Google Scholar 
    62.Muthayya, S. et al. The global hidden hunger indices and maps: An advocacy tool for action. PLoS ONE 8, e67860. https://doi.org/10.1371/journal.pone.0067860 (2013).CAS 
    Article 
    PubMed 
    PubMed Central 
    ADS 

    Google Scholar 
    63.Joy, E. J. et al. Dietary mineral supplies in Africa. Physiol. Plant. 151, 208–229 (2014).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    64.World Health Organization. World health statistics 2015. https://apps.who.int/iris/bitstream/handle/10665/170250/9789240694439_eng.pdf;jsessionid=9CFCB446F9217B60415DD216E70F6A49?sequence=1 (2015).65.Muriuki, J. M. et al. Estimating the burden of iron deficiency among African children. BMC Med. 18, 31. https://doi.org/10.1186/s12916-020-1502-7 (2020).CAS 
    Article 
    PubMed 
    PubMed Central 

    Google Scholar 
    66.Official Journal of the European Union. Regulation (Eu) No 1169/2011 of the European Parliament and of the Council of 25 October 2011. https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32011R1169&from=EN (2011).67.Nowicka, A. et al. Nuclear DNA content variation within the genus Daucus (Apiaceae) determined by flow cytometry. Sci. Hortic. 209, 132–138 (2016).CAS 
    Article 

    Google Scholar 
    68.Guilengue, N., Alves, S., Talhinhas, P. & Neves-Martins, J. Genetic and genomic diversity in a tarwi (Lupinus mutabilis Sweet) germplasm collection and adaptability to Mediterranean climate conditions. Agronomy 10, 21. https://doi.org/10.3390/agronomy10010021 (2020).Article 

    Google Scholar 
    69.Chable, V. et al. Embedding cultivated diversity in society for agro-ecological transition. Sustainability 12, 784. https://doi.org/10.3390/su12030784 (2020).Article 

    Google Scholar 
    70.Knight, C. A., Molinari, N. A. & Petrov, D. A. The large genome constraint hypothesis: Evolution, ecology and phenotype. Ann. Bot. 95, 177–190 (2005).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    71.Pati, K., Zhang, F. & Batley, J. First report of genome size and ploidy of the underutilized leguminous tuber crop Yam Bean (Pachyrhizus erosus and P. tuberosus) by flow cytometry. Plant Genet. Resour. 17, 456–459 (2019).CAS 
    Article 

    Google Scholar 
    72.Sliwinska, E. Flow cytometry—A modern method for exploring genome size and nuclear DNA synthesis in horticultural and medicinal plant species. Folia Hortic. 30, 103–128 (2018).Article 

    Google Scholar 
    73.Veselý, P., Bureš, P. & Šmarda, P. Nutrient reserves may allow for genome size increase: Evidence from comparison of geophytes and their sister non-geophytic relatives. Ann. Bot. 112, 1193–1200 (2013).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    74.African Plant Database. http://www.ville-ge.ch/musinfo/bd/cjb/africa/index. (2021).75.Hyde, M. A., Wursten, B. T., Ballings, P. & Coates Palgrave, M. Flora of Botswana. https://www.botswanaflora.com (2021).76.Hyde, M. A., Wursten, B. T., Ballings, P. & Coates Palgrave, M. Flora of Malawi. http://www.malawiflora.com (2021).77.Hyde, M. A., Wursten, B. T., Ballings, P. & Coates Palgrave, M. Flora of Mozambique. http://www.mozambiqueflora.com (2021)78.Bingham, M. G., Willemen, A., Wursten, B. T., Ballings, P. & Hyde, M. A. Flora of Zambia http://www.zambiaflora.com (2021).79.Hyde, M. A., Wursten, B. T., Ballings, P. & Coates Palgrave, M. Flora of Zimbabwe. http://www.zimbabweflora.co.zw (2021).80.International Legume Database & Information Service. https://ildis.org/LegumeWeb (2020).81.Exell, A.W. & Fernandes, A. Conspectus florae angolensis. Vol. 3, No. 2. Leguminosae (Papilionoideae: Hedysareae-Sophoreae) (Junta de Investigações do Ultramar, 1966)82.Pasquet, R. S. Notes on the genus Vigna (Leguminosae-Papilionoideae). Kew Bull 56, 223–227 (2001).Article 

    Google Scholar 
    83.van Zonneveld, M. et al. Mapping patterns of abiotic and biotic stress resilience uncovers conservation gaps and breeding potential of Vigna wild relatives. Sci. Rep. 10, 2111. https://doi.org/10.1038/s41598-020-58646-8 (2020).CAS 
    Article 
    PubMed 
    PubMed Central 
    ADS 

    Google Scholar 
    84.Global Biodiversity Information Facility. https://www.gbif.org/ (2021).85.GBIF Occurrence Download—Vigna. https://doi.org/10.15468/dl.bsjsk5 (2021).86.GBIF Occurrence Download—Phaseolus. https://doi.org/10.15468/dl.kjw72 (2021).87.QGIS Development Team. QGIS Geographic Information System. Open Source Geospatial Foundation Project. http://qgis.osgeo.org (2021).88.Doležel, J., Sgorbati, S. & Lucretti, S. Comparison of three DNA fluorochromes for flow cytometric estimation of nuclear DNA content in plants. Physiol. Plant. 85, 625–631 (1992).Article 

    Google Scholar 
    89.Loureiro, J., Rodriguez, E., Doležel, J. & Santos, C. Two new nuclear isolation buffers for plant DNA flow cytometry: A test with 37 species. Ann. Bot. 100, 875–888 (2007).CAS 
    PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    90.Doležel, J. & Bartoš, J. Plant DNA flow cytometry and estimation of nuclear genome size. Ann. Bot. 95, 99–110 (2005).PubMed 
    PubMed Central 
    Article 
    CAS 

    Google Scholar 
    91.Doležel, J., Bartoš, J., Voglmayr, H. & Greilhuber, J. Nuclear DNA content and genome size of trout and human. Cytometry 51, 127–128 (2003).PubMed 
    Article 
    PubMed Central 

    Google Scholar 
    92.Jelihovschi, E. G., Faria, J. C. & Allaman, I. B. ScottKnott: A package for performing the Scott-Knott clustering algorithm in R. TEMA 15, 3–17 (2014).MathSciNet 
    Article 

    Google Scholar 
    93.Wickham, H. ggplot2: Elegant Graphics for Data Analysis (Springer, 2016).MATH 
    Book 

    Google Scholar 
    94.R Core Team. R: A language and environment for statistical computing https://www.R-project.org/ (R Foundation for Statistical Computing, 2020). More

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    Salmon going viral

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    Oil palm cultivation can be expanded while sparing biodiversity in India

    1.Vijay, V., Pimm, S. L., Jenkins, C. N. & Smith, S. J. The impacts of oil palm on recent deforestation and biodiversity loss. PLoS One 11, pe0159668 (2016).Article 

    Google Scholar 
    2.Rulli, M. C. et al. Interdependencies and telecoupling of oil palm expansion at the expense of Indonesian rainforest. Renew. Sustain. Energy Rev. 105, 499–512 (2019).Article 

    Google Scholar 
    3.Davis, K. F. et al. Tropical forest loss enhanced by large-scale land acquisitions. Nat. Geosci. 13, 482–488 (2020).ADS 
    CAS 
    Article 

    Google Scholar 
    4.Strona, G. et al. Small room for compromise between oil palm cultivation and primate conservation in Africa. Proc. Natl Acad. Sci. USA 115, 8811–8816 (2018).CAS 
    Article 

    Google Scholar 
    5.United States Department of Agriculture, Foreign Agricultural Service. Data retrieved from: https://apps.fas.usda.gov/psdonline/app/index.html#/app/advQuery (2020).6.Sagar, H. S. et al. India in the oil palm era: describing India’s dependence on palm oil, recommendations for sustainable production, and opportunities to become an influential consumer. Trop. Conserv. Sci. 12, 1940082919838918 (2019).Article 

    Google Scholar 
    7.Jadhav, R. Exclusive: India urges boycott of Malaysian palm oil after diplomatic row—sources. Reuters (13 January 2020).8.Srinivasan, U. Oil palm should not be expanded in Arunachal Pradesh. Arunachal Times (October 2016).9.Ministry of Agriculture and Farmers’ Welfare. National Mission on Oilseeds and Oil Palm; https://nmoop.gov.in (Government of India, 2020).10.Bose, P. Oil palm plantations vs shifting cultivation for indigenous peoples: analyzing Mizoram’s New Land Use Policy. Land Use Policy 81, 115–123 (2019).Article 

    Google Scholar 
    11.Dhar, A. Enter oil palm in northeast India: centre, Patanjali, Godrej bet big. The Citizen (16 September 2020).12.Raman, T. R. S. R. Is oil palm expansion good for Mizoram? The Frontier Despatch 3, 6–7 (2016).
    Google Scholar 
    13.Khandekar, N. Expanding oil palm plantations in the northeast could extract a long-term cost. The Wire (4 August 2020).14.Mandal, J. & Raman, T. R. S. R. Shifting agriculture supports more tropical forest birds than oil palm or teak plantations in Mizoram, northeast India. The Condor 118, 345–359 (2016).Article 

    Google Scholar 
    15.Nandi, J. Oil palm push on the northeast may impact biodiversity, water table, say experts. Hindustan Times 10, 51 (2020).
    Google Scholar 
    16.Myers, N., Mittermeier, R. A., Mittermeier, C. G., Da Fonseca, G. A. B. & Kent, J. Biodiversity hotspots for conservation priorities. Nature 403, 853–858 (2000).ADS 
    CAS 
    Article 

    Google Scholar 
    17.Global Agro-Ecological Zones, GAEZ v.3.0 (Food and Agriculture Organization, 2016); https://gaez.fao.org/pages/data-viewer18.Corley, R. H. V. How much palm oil do we need? Environ. Sci. Policy 12, 134–139 (2009).CAS 
    Article 

    Google Scholar 
    19.Meijaard, E. et al. The environmental impacts of palm oil in context. Nat. Plants 6, 1418–1426 (2020).Article 

    Google Scholar 
    20.West, P. C. et al. Leverage points for improving global food security and the environment. Science 18, 325–328 (2014).ADS 
    Article 

    Google Scholar 
    21.Fan, Y., Li, H. & Miguez-Macho, G. Global patterns of groundwater table depth. Science 339, 940–943 (2013).22.Shaktivadivel, R. The Agricultural Groundwater Revolution: Opportunities and Threats to Development (CAB International, 2007).
    Google Scholar 
    23.Lee, J. S. H., Miteva, D. A., Carlson, K. M., Heilmayr, R. & Saif, O. Does oil palm certification create trade-offs between environment and development in Indonesia? Env. Res. Lett. 15, 124064 (2020).Article 

    Google Scholar 
    24.Sankar, K. N. M. Oil palm finds favour with East Godavari farmers. The Hindu (25 January 2017).25.Curry, G. N. & Koczberski, G. Finding common ground: relational concepts of land tenure and economy in the oil palm frontier of Papua New Guinea. Geogr. J. 175, 98–111 (2009).Article 

    Google Scholar 
    26.DeVos, R., Kohne, M. & Roth, D. We’ll turn your water in Coca Cola: the atomising practices of oil palm development in Indonesia. J. Agrar. Change 1, 385–405 (2018).Article 

    Google Scholar 
    27.IPCC. Climate Change: Synthesis Report (eds Core Writing Team, Pachauri, R. K. & Meyer, L. A.) (IPCC, 2014).28.IPCC. IPCC Special Reports on Emissions Scenarios: Summary for Policymakers (IPCC, 2000).29.Schwalm, C. R., Glendon, S. & Duffy, P. B. RCP8. 5 tracks cumulative CO2 emissions. Proc. Natl Acad. Sci. USA 18, 19656–19657 (2020).ADS 
    Article 

    Google Scholar 
    30.Copernicus Land Monitoring Service (European Environment Agency, 2020).31.Hoffman, M., Koenig, K., Bunting, G., Cosntanza, J. & Willams, K. J. Biodiversity Hotspots v.2016.1 (2016); https://doi.org/10.5281/zenodo.326180632.IUCN World Database on Protected Areas, online April 2017 (UNEP-WCMC, 2016); www.protectedplanet.net33.QGIS Development Team. QGIS Geographic Information System (Open Source Geospatial Foundation, 2021); http://qgis.osgeo.org34.R Core Team. R: A Language and Environment for Statistical Computing (R Foundation for Statistical Computing, 2021). More

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    A rapid phenotype change in the pathogen Perkinsus marinus was associated with a historically significant marine disease emergence in the eastern oyster

    1.Lafferty, K. D., Porter, J. W. & Ford, S. E. Are diseases increasing in the ocean?. Annu. Rev. Ecol. Evol. Syst. 35, 31–54 (2004).Article 

    Google Scholar 
    2.Lafferty, K. D. et al. Infectious diseases affect marine fisheries and aquaculture economics. Annu. Rev. Mar. Sci. 7, 471–496 (2015).Article 
    ADS 

    Google Scholar 
    3.Burreson, E. M., Stokes, N. A. & Friedman, C. S. Increased virulence in an introduced pathogen: Haplosporidium nelsoni (MSX) in the eastern oyster Crassostrea virginica. J. Aquat. Anim. Health 12, 1–8 (2000).CAS 
    PubMed 
    Article 

    Google Scholar 
    4.Elston, R. A., Farley, C. A. & Kent, M. L. Occurrence and significance of bonamiasis in European flat oysters Ostrea edulis in North America. Dis. Aquat. Org. 2, 49–54 (1986).Article 

    Google Scholar 
    5.Enzmann, P.-J., Kurath, G., Fichtner, D. & Bergmann, S. M. Infectious hematopoietic necrosis virus: Monophyletic origin of European isolates from North American genogroup M. Dis. Aquat. Org. 66, 187–195 (2005).CAS 
    Article 

    Google Scholar 
    6.Lightner, D. V. The penaeid shrimp viral pandemics due to IHHNV, WSSV, TSV and YHV: History in the Americas and current status (Proceedings of the 32nd Joint UJNR Aquaculture Panel Symposium, Davis and Santa Barbara, California, USA, 2003).7.Sutherland, K. P., Shaban, S., Joyner, J. L., Porter, J. W. & Lipp, E. K. Human pathogen shown to cause disease in the threatened elkhorn coral Acropora palmata. PLoS ONE 6, e23468 (2011).CAS 
    PubMed 
    PubMed Central 
    Article 
    ADS 

    Google Scholar 
    8.Chang, P. et al. Herpes-like virus infection causing mortality of cultured abalone Haliotis diversicolor supertexta in Taiwan. Dis. Aquat. Org. 65, 23–27 (2005).Article 

    Google Scholar 
    9.Hooper, C., Hardy-Smith, P. & Handlinger, J. Ganglioneuritis causing high mortalities in farmed Australian abalone (Haliotis laevigata and Haliotis rubra). Aust. Vet. J. 85, 188–193 (2007).CAS 
    PubMed 
    Article 

    Google Scholar 
    10.Segarra, A. et al. Detection and description of a particular Ostreid herpesvirus 1 genotype associated with massive mortality outbreaks of Pacific oysters, Crassostrea gigas, in France in 2008. Virus Res. 153, 92–99 (2010).CAS 
    PubMed 
    Article 

    Google Scholar 
    11.Jenkins, C. et al. Identification and characterisation of an ostreid herpesvirus-1 microvariant (OsHV-1 μ-var) in Crassostrea gigas (Pacific oysters) in Australia. Dis. Aquat. Org. 105, 109–126 (2013).CAS 
    Article 

    Google Scholar 
    12.Mackin, J. G. Oyster disease caused by Dermocystidium marinum and other microorganisms in Louisiana. Pub. Inst. Mar. Sci. Univ. Texas 7, 132–229 (1962).
    Google Scholar 
    13.Andrews, J. D. Epizootiology of the disease caused by the oyster pathogen Perkinsus marinus and its effects on the oyster industry. Am. Fish. Soc. Spec. Pub. 18, 47–63 (1988).
    Google Scholar 
    14.Burreson, E. M. & Andrews, J. D. Unusual intensification of Chesapeake Bay oyster diseases during recent drought conditions. In Proceeding of the Oceans ’88 Conference, Baltimore, Maryland, USA, 1988) 799–802.15.Ford, S. E. Range extension by the oyster parasite Perkinsus marinus into the northeastern United States: Response to climate change?. J. Shellfish Res. 15, 45–56 (1996).
    Google Scholar 
    16.Harvell, C. D. et al. Emerging marine diseases: Climate links and anthropogenic factors. Science 285, 1505–1510 (1999).CAS 
    PubMed 
    Article 

    Google Scholar 
    17.Burge, C. A. et al. Climate change influences on marine infectious diseases: Implications for management and society. Annu. Rev. Mar. Sci. 6, 249–277 (2014).Article 
    ADS 

    Google Scholar 
    18.Cook, T., Folli, M., Klinck, J., Ford, S. & Miller, J. The relationship between increasing sea-surface temperature and the northward spread of Perkinsus marinus (Dermo) disease epizootics in oysters. Estuar. Coast. Shelf Sci. 46, 587–597 (1998).Article 
    ADS 

    Google Scholar 
    19.Crosby, M. P. & Roberts, C. F. Seasonal infection intensity cycle of the parasite Perkinsus marinus (and an absence of Haplosporidium spp.) in oysters from a South Carolina salt marsh. Dis. Aquat. Org. 9, 149–155 (1990).Article 

    Google Scholar 
    20.Shearman, R. K. & Lentz, S. J. Long-term sea surface temperature variability along the U.S. East Coast. J. Phys. Oceanogr. 40, 1004–1017 (2010).Article 
    ADS 

    Google Scholar 
    21.Ray, S. M. A culture technique for the diagnosis of infections with Dermocystidium marinus Mackin, Owen, and Collier in oysters. Science 116, 360–361 (1952).CAS 
    PubMed 
    Article 
    ADS 

    Google Scholar 
    22.Carnegie, R. B., Arzul, I. & Bushek, D. Managing marine mollusc diseases in the context of regional and international commerce: Policy issues and emerging concerns. Phil. Trans. R. Soc. B 371, 20150215 (2016).PubMed 
    Article 
    CAS 

    Google Scholar 
    23.OIE Infection with Perkinsus marinus. In Manual of Diagnostic Tests for Aquatic Animals 7th edn 526–538 (OIE, Paris, 2016).
    Google Scholar 
    24.Mackin, J. G., Owen, H. M. & Collier, A. Preliminary note on the occurrence of a new protistan parasite, Dermocystidium marinum n sp in Crassostrea virginica (Gmelin). Science 111, 328–329 (1950).25.Perkins, F. O. Ultrastructure of vegetative stages in Labyrinthomyxa marina (Dermocystidium marinum), a commercially significant oyster pathogen. J. Invertebr. Pathol. 13, 199–222 (1969).CAS 
    PubMed 
    Article 

    Google Scholar 
    26.Gates, D. E., Valletta, J. J., Bonneaud, C. & Recker, M. Quantitative host resistance drives the evolution of increased virulence in an emerging pathogen. J. Evol. Biol. 31, 1704–1714 (2018).PubMed 
    Article 

    Google Scholar 
    27.Moss, J. A., Burreson, E. M. & Reece, K. S. Advanced Perkinsus marinus infections in Crassostrea ariakensis maintained under laboratory conditions. J. Shellfish Res. 25, 65–72 (2006).Article 

    Google Scholar 
    28.Reece, K. S., Bushek, D., Hudson, K. L. & Graves, J. E. Geographic distribution of Perkinsus marinus genetic strains along the Atlantic and Gulf coasts of the USA. Mar. Biol. 139, 1047–1055 (2001).Article 

    Google Scholar 
    29.Thompson, P. C., Rosenthal, B. M. & Hare, M. P. Microsatellite genotypes reveal some long-distance gene flow in Perkinsus marinus, a major pathogen of the eastern oyster, Crassostrea virginica (Gmelin). J. Shellfish Res. 33, 195–206 (2014).Article 

    Google Scholar 
    30.Andrews, J. D. Epizootiology of diseases of oysters (Crassostrea virginica), and parasites of associated organisms in eastern North America. Helgoländer Meeresuntersuchungen 37, 149–166 (1984).Article 

    Google Scholar 
    31.Haven, D. S., Hargis, W. J., Jr. & Kendall, P. C. The oyster industry of Virginia: Its Status, Problems and Promise (VA Institute of Marine Science Special Papers in Marine Science No. 4, 1978).32.Andrews, J. D. Perkinsus marinus = Dermocystidium marinum (“Dermo”) in Virginia, 1950–1980 (VA Institute of Marine Science Data Report No. 16, 1980).33.Hite, J. L. & Cressler, C. E. Resource-driven changes to host population stability alter the evolution of virulence and transmission. Phil. Trans. R. Soc. B 373, 20170087 (2018).PubMed 
    Article 

    Google Scholar 
    34.Rick, T. C. et al. Millennial-scale sustainability of the Chesapeake Bay Native American oyster fishery. Proc. Natl. Acad. Sci. USA 113, 6568–6573 (2016).CAS 
    PubMed 
    Article 

    Google Scholar 
    35.Bushek, D., Ford, S. E. & Chintala, M. M. Comparison of in vitro-cultured and wild-type Perkinsus marinus. III. Fecal elimination and its role in transmission. Dis. Aquat. Org. 51, 217–225 (2002).Article 

    Google Scholar 
    36.Mann, R., Southworth, M., Harding, J. M. & Wesson, J. A. Population studies of the native eastern oyster, Crassostrea virginica (Gmelin, 1791) in the James River, Virginia, USA. J. Shellfish Res. 28, 193–220 (2009).Article 

    Google Scholar 
    37.Andrews, J. D. Oyster mortality studies in Virginia. IV. MSX in James River public seed beds. Proc. Natl. Shellfish. Assoc. 53, 65–84 (1964).
    Google Scholar 
    38.Carnegie, R. B. & Burreson, E. M. Declining impact of an introduced pathogen: Haplosporidium nelsoni in the oyster Crassostrea virginica in Chesapeake Bay. Mar. Ecol. Prog. Ser. 432, 1–15 (2011).Article 
    ADS 

    Google Scholar 
    39.Goedknegt, M. A. et al. Parasites and marine invasions: Ecological and evolutionary perspectives. J. Sea Res. 113, 11–27 (2016).Article 
    ADS 

    Google Scholar 
    40.Kemp, W. M. et al. Eutrophication of Chesapeake Bay: Historical trends and ecological interactions. Mar. Ecol. Prog. Ser. 303, 1–29 (2005).Article 
    ADS 

    Google Scholar 
    41.Ford, S. E. & Bushek, D. Development of resistance to an introduced marine pathogen by a native host. J. Mar. Res. 70, 205–223 (2012).Article 

    Google Scholar 
    42.Bobo, M. Y., Richardson, D. L., Coen, L. D. & Burrell, V. G. A Report on the Protozoan Pathogens Perkinsus marinus (dermo) and Haplosporidium nelsoni (MSX) in South Carolina shellfish populations (Tech. Rep. No. 86, SC Dept. of Natural Resources, 1997).43.Hill, K. M. et al. Observation of a Bonamia sp. infecting the oyster Ostrea stentina in Tunisia, and a consideration of its phylogenetic affinities. J. Invertebr. Pathol. 103, 179–185 (2010).PubMed 
    Article 

    Google Scholar 
    44.Carnegie, R. B. et al. Molecular detection of the oyster parasite Mikrocytos mackini, and a preliminary phylogenetic analysis. Dis. Aquat. Org. 54, 219–227 (2003).CAS 
    Article 

    Google Scholar 
    45.Stokes, N. A. & Burreson, E. M. A sensitive and specific DNA probe for the oyster pathogen Haplosporidium nelsoni. J. Eukaryot. Microbiol. 42, 350–357 (1995).CAS 
    PubMed 
    Article 

    Google Scholar 
    46.Reece, K. S., Dungan, C. F. & Burreson, E. M. Molecular epizootiology of Perkinsus marinus and P. chesapeaki infections among wild oysters and clams in Chesapeake Bay, USA. Dis. Aquat. Org. 82, 237–248 (2008).CAS 
    Article 

    Google Scholar 
    47.Carnegie, R. B. Status of the Major Oyster Diseases in Virginia, 2009–2012: A Summary of the Annual Oyster Disease Monitoring Program (Virginia Institute of Marine Science, 2013).
    Google Scholar 
    48.Andrews, J. D. & Hewatt, W. G. Oyster mortality studies in Virginia II The fungus disease caused by Dermocystidium marinum in Chesapeake Bay. Ecol. Monogr. 27, 1–26 (1957).Article 

    Google Scholar 
    49.Perkins, F. O. The structure of Perkinsus marinus (Mackin, Owen and Collier, 1950) Levine, 1978 with comments on taxonomy and phylogeny of Perkinsus spp. J. Shellfish Res. 15, 67–87 (1996).
    Google Scholar 
    50.RStudio Team. RStudio: Integrated Development for R. (RStudio, Inc., 2019). http://www.rstudio.com/.51.R Core Team. R: A Language and Environment for Statistical Computing. (R Foundation for Statistical Computing, 2020). https://www.R-project.org/.52.Wickham, H. et al. Welcome to the Tidyverse. J. Open Source Softw. 4, 1686 (2019).Article 
    ADS 

    Google Scholar 
    53.Wickham, H. forcats: Tools for Working with Categorical Variables (Factors). R Package Version 0.5.1. https://CRAN.R-project.org/package=forcats (2021).54.Fox, J. & Weisberg, S. An R Companion to Applied Regression 3rd edn. (Sage Publications, 2019).
    Google Scholar 
    55.Zar, J. H. Biostatistical Analysis 3rd edn. (Prentice Hall, 1996).
    Google Scholar 
    56.Ragone, L. M. & Burreson, E. M. Effect of salinity on infection progression and pathogenicity of Perkinsus marinus in the eastern oyster, Crassostrea virginica (Gmelin). J. Shellfish Res. 12, 1–7 (1993).
    Google Scholar 
    57.Chu, F.-L.E., Volety, A. K. & Constantin, G. A comparison of Crassostrea gigas and Crassostrea virginica: Effects of temperature and salinity on susceptibility to the protozoan parasite, Perkinsus marinus. J. Shellfish Res. 15, 375–380 (1996).
    Google Scholar  More

  • in

    Observed increasing water constraint on vegetation growth over the last three decades

    1.Novick, K. A. et al. The increasing importance of atmospheric demand for ecosystem water and carbon fluxes. Nat. Clim. Change 6, 1023–1027 (2016).CAS 
    Article 
    ADS 

    Google Scholar 
    2.Ciais, P. et al. Europe-wide reduction in primary productivity caused by the heat and drought in 2003. Nature 437, 529 (2005).CAS 
    PubMed 
    Article 
    ADS 

    Google Scholar 
    3.Porporato, A., D’odorico, P., Laio, F., Ridolfi, L. & Rodriguez-Iturbe, I. Ecohydrology of water-controlled ecosystems. Adv. Water Resour. 25, 1335–1348 (2002).Article 
    ADS 

    Google Scholar 
    4.Huang, K. et al. Enhanced peak growth of global vegetation and its key mechanisms. Nat. Ecol. Evolution 2, 1897 (2018).Article 

    Google Scholar 
    5.Huang, J., Yu, H., Guan, X., Wang, G. & Guo, R. Accelerated dryland expansion under climate change. Nat. Clim. Change 6, 166 (2016).Article 
    ADS 

    Google Scholar 
    6.Yuan, W. et al. Increased atmospheric vapor pressure deficit reduces global vegetation growth. Sci. Adv. 5, eaax1396 (2019).CAS 
    PubMed 
    PubMed Central 
    Article 
    ADS 

    Google Scholar 
    7.Jung, M. et al. Recent decline in the global land evapotranspiration trend due to limited moisture supply. Nature 467, 951 (2010).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    8.Sherwood, S. & Fu, Q. A drier future? Science 343, 737–739 (2014).CAS 
    PubMed 
    Article 
    ADS 

    Google Scholar 
    9.Lucht, W. et al. Climatic control of the high-latitude vegetation greening trend and Pinatubo effect. Science 296, 1687–1689 (2002).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    10.Zhu, Z. et al. Greening of the Earth and its drivers. Nat. Clim. change 6, 791–795 (2016).CAS 
    Article 
    ADS 

    Google Scholar 
    11.Fensholt, R. et al. Greenness in semi-arid areas across the globe 1981–2007—an Earth Observing Satellite based analysis of trends and drivers. Remote Sens. Environ. 121, 144–158 (2012).Article 
    ADS 

    Google Scholar 
    12.Fernández-Martínez, M. et al. Global trends in carbon sinks and their relationships with CO2 and temperature. Nat. Clim. change 9, 73 (2019).Article 
    ADS 
    CAS 

    Google Scholar 
    13.Dannenberg, M. P., Wise, E. K. & Smith, W. K. Reduced tree growth in the semiarid United States due to asymmetric responses to intensifying precipitation extremes. Sci. Adv. 5, eaaw0667 (2019).PubMed 
    PubMed Central 
    Article 
    ADS 

    Google Scholar 
    14.Piao, S. et al. Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity. Nat. Commun. 5, 5018 (2014).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    15.Wild, M. et al. From dimming to brightening: decadal changes in solar radiation at Earth’s surface. Science 308, 847–850 (2005).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

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

    Google Scholar 
    17.Forzieri, G., Alkama, R., Miralles, D. G. & Cescatti, A. Satellites reveal contrasting responses of regional climate to the widespread greening of Earth. Science 356, 1180–1184 (2017).CAS 
    PubMed 
    Article 
    PubMed Central 

    Google Scholar 
    18.Vicente-Serrano, S. M. et al. Response of vegetation to drought time-scales across global land biomes. Proc. Natl Acad. Sci. USA 110, 52–57 (2013).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    19.Anderegg, W. R. et al. Hydraulic diversity of forests regulates ecosystem resilience during drought. Nature 561, 538 (2018).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    20.Keenan, T. F. et al. Increase in forest water-use efficiency as atmospheric carbon dioxide concentrations rise. Nature 499, 324 (2013).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    21.Jiao, W., Wang, L. & McCabe, M. F. Multi-sensor remote sensing for drought characterization: current status, opportunities and a roadmap for the future. Remote Sens. Environ. 256, 112313 (2021).Article 
    ADS 

    Google Scholar 
    22.Lobell, D. B. et al. Greater sensitivity to drought accompanies maize yield increase in the US Midwest. Science 344, 516–519 (2014).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    23.Saleska, S. R., Didan, K., Huete, A. R. & Da Rocha, H. R. Amazon forests green-up during 2005 drought. Science 318, 612–612 (2007).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    24.Chen, T., Werf, G., Jeu, R., Wang, G. & Dolman, A. A global analysis of the impact of drought on net primary productivity. Hydrol. Earth Syst. Sci. 17, 3885 (2013).Article 
    ADS 

    Google Scholar 
    25.Nemani, R. R. et al. Climate-driven increases in global terrestrial net primary production from 1982 to 1999. Science 300, 1560–1563 (2003).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    26.Kreuzwieser, J. & Rennenberg, H. Molecular and physiological responses of trees to waterlogging stress. Plant, Cell Environ. 37, 2245–2259 (2014).CAS 

    Google Scholar 
    27.Buermann, W. et al. Widespread seasonal compensation effects of spring warming on northern plant productivity. Nature 562, 110 (2018).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    28.Zhao, M. & Running, S. W. Drought-induced reduction in global terrestrial net primary production from 2000 through 2009. Science 329, 940–943 (2010).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    29.Anderegg, W. R. et al. Pervasive drought legacies in forest ecosystems and their implications for carbon cycle models. Science 349, 528–532 (2015).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    30.Field, C. B., Barros, V., Stocker, T. F. & Dahe, Q. Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation: Special Report of the Intergovernmental Panel on Climate Change. (Cambridge University Press, 2012).31.Dai, A. Increasing drought under global warming in observations and models. Nat. Clim. Change 3, 52 (2013).Article 
    ADS 

    Google Scholar 
    32.Trenberth, K. E. et al. Global warming and changes in drought. Nat. Clim. Change 4, 17 (2013).Article 
    ADS 

    Google Scholar 
    33.Cook, B. I., Ault, T. R. & Smerdon, J. E. Unprecedented 21st century drought risk in the American Southwest and Central Plains. Sci. Adv. 1, e1400082 (2015).PubMed 
    PubMed Central 
    Article 
    ADS 

    Google Scholar 
    34.Milly, P. C. & Dunne, K. A. Potential evapotranspiration and continental drying. Nat. Clim. Change 6, 946 (2016).Article 
    ADS 

    Google Scholar 
    35.Xu, C. et al. Increasing impacts of extreme droughts on vegetation productivity under climate change. Nat. Clim. Change 9, 948–953 (2019).CAS 
    Article 
    ADS 

    Google Scholar 
    36.Konapala, G., Mishra, A. K., Wada, Y. & Mann, M. E. Climate change will affect global water availability through compounding changes in seasonal precipitation and evaporation. Nat. Commun. 11, 1–10 (2020).Article 
    CAS 

    Google Scholar 
    37.Peñuelas, J. et al. Shifting from a fertilization-dominated to a warming-dominated period. Nat. Ecol. Evolution 1, 1438–1445 (2017).Article 

    Google Scholar 
    38.Humphrey, V. et al. Sensitivity of atmospheric CO2 growth rate to observed changes in terrestrial water storage. Nature 560, 628–631 (2018).CAS 
    PubMed 
    Article 
    ADS 

    Google Scholar 
    39.Vicente-Serrano, S. M., Beguería, S. & López-Moreno, J. I. A multiscalar drought index sensitive to global warming: the standardized precipitation evapotranspiration index. J. Clim. 23, 1696–1718 (2010).Article 
    ADS 

    Google Scholar 
    40.Doughty, C. E. et al. Drought impact on forest carbon dynamics and fluxes in Amazonia. Nature 519, 78–82 (2015).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    41.Schwalm, C. R. et al. Global patterns of drought recovery. Nature 548, 202 (2017).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    42.Peters, W. et al. Increased water-use efficiency and reduced CO2 uptake by plants during droughts at a continental scale. Nat. Geosci. 11, 744 (2018).CAS 
    PubMed 
    PubMed Central 
    Article 
    ADS 

    Google Scholar 
    43.Hugelius, G. et al. Large stocks of peatland carbon and nitrogen are vulnerable to permafrost thaw. Proc. Natl Acad. Sci. USA 117, 20438–20446 (2020).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    44.Minasny, B. et al. Digital mapping of peatlands–A critical review. Earth-Sci. Rev. 196, 102870 (2019).CAS 
    Article 

    Google Scholar 
    45.Cronk, J. K. & Fennessy, M. S. Wetland Plants: Biology and Ecology. (CRC press, 2016).46.Zohaib, M. & Choi, M. Satellite-based global-scale irrigation water use and its contemporary trends. Sci. Total Environ. 714, 136719 (2020).47.Smith, W. K. et al. Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization. Nat. Clim. Change 6, 306 (2016).Article 
    ADS 
    CAS 

    Google Scholar 
    48.Abel, C. et al. The human–environment nexus and vegetation–rainfall sensitivity in tropical drylands. Nat. Sustain. 4, 25–32 (2020).49.Lu, X., Wang, L. & McCabe, M. F. Elevated CO2 as a driver of global dryland greening. Sci. Rep. 6, 20716 (2016).CAS 
    PubMed 
    PubMed Central 
    Article 
    ADS 

    Google Scholar 
    50.Oliveira, P. J., Davin, E. L., Levis, S. & Seneviratne, S. I. Vegetation‐mediated impacts of trends in global radiation on land hydrology: a global sensitivity study. Glob. Change Biol. 17, 3453–3467 (2011).Article 
    ADS 

    Google Scholar 
    51.Grömping, U. Relative importance for linear regression in R: the package relaimpo. J. Stat. Softw. 17, 1–27 (2006).Article 

    Google Scholar 
    52.Moesinger, L. et al. The global long-term microwave vegetation optical depth climate archive (VODCA). Earth Syst. Sci. Data 12, 177–196 (2020).Article 
    ADS 

    Google Scholar 
    53.Li, X. & Xiao, J. A global, 0.05-degree product of solar-induced chlorophyll fluorescence derived from OCO-2, MODIS, and reanalysis data. Remote Sens. 11, 517 (2019).Article 
    ADS 

    Google Scholar 
    54.Palmer, W. C. Meteorological Drought. Vol. 30 (Citeseer, 1965).55.Abatzoglou, J. T., Dobrowski, S. Z., Parks, S. A. & Hegewisch, K. C. TerraClimate, a high-resolution global dataset of monthly climate and climatic water balance from 1958–2015. Sci. Data 5, 170191 (2018).PubMed 
    PubMed Central 
    Article 

    Google Scholar 
    56.Trabucco, A. & Zomer, R. J. Global aridity index (global-aridity) and global potential evapo-transpiration (global-PET) geospatial database. CGIAR Consortium for Spatial Information (2009).57.Zomer, R. J., Trabucco, A., Bossio, D. A. & Verchot, L. V. Climate change mitigation: a spatial analysis of global land suitability for clean development mechanism afforestation and reforestation. Agriculture, Ecosyst. Environ. 126, 67–80 (2008).Article 

    Google Scholar 
    58.Gruber, A., Scanlon, T., Schalie, R. V. D., Wagner, W. & Dorigo, W. Evolution of the ESA CCI soil moisture climate data records and their underlying merging methodology. Earth Syst. Sci. Data 11, 717–739 (2019).Article 
    ADS 

    Google Scholar 
    59.Dorigo, W. et al. ESA CCI Soil moisture for improved Earth system understanding: State-of-the art and future directions. Remote Sens. Environ. 203, 185–215 (2017).Article 
    ADS 

    Google Scholar 
    60.Wagner, W. et al. Fusion of active and passive microwave observations to create an essential climate variable data record on soil moisture. ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences (ISPRS Annals) 7, 315–321 (2012).61.Harris, I., Jones, P., Osborn, T. & Lister, D. Updated high‐resolution grids of monthly climatic observations–the CRU TS3. 10 Dataset. Int. J. Climatol. 34, 623–642 (2014).Article 

    Google Scholar 
    62.Sheffield, J., Goteti, G. & Wood, E. F. Development of a 50-year high-resolution global dataset of meteorological forcings for land surface modeling. J. Clim. 19, 3088–3111 (2006).Article 
    ADS 

    Google Scholar 
    63.Tian, F. et al. Remote sensing of vegetation dynamics in drylands: Evaluating vegetation optical depth (VOD) using AVHRR NDVI and in situ green biomass data over West African Sahel. Remote Sens. Environ. 177, 265–276 (2016).Article 
    ADS 

    Google Scholar 
    64.Reichstein, M. et al. Climate extremes and the carbon cycle. Nature 500, 287–295 (2013).CAS 
    PubMed 
    PubMed Central 
    Article 
    ADS 

    Google Scholar 
    65.Frank, D. et al. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts. Glob. Change Biol. 21, 2861–2880 (2015).Article 
    ADS 

    Google Scholar 
    66.Goetz, S. J., Bunn, A. G., Fiske, G. J. & Houghton, R. A. Satellite-observed photosynthetic trends across boreal North America associated with climate and fire disturbance. Proc. Natl Acad. Sci. USA 102, 13521–13525 (2005).CAS 
    PubMed 
    Article 
    ADS 
    PubMed Central 

    Google Scholar 
    67.Wu, D. et al. Time‐lag effects of global vegetation responses to climate change. Glob. Change Biol. 21, 3520–3531 (2015).Article 
    ADS 

    Google Scholar 
    68.Tei, S. & Sugimoto, A. Time lag and negative responses of forest greenness and tree growth to warming over circumboreal forests. Glob. Change Biol. 24, 4225–4237 (2018).Article 
    ADS 

    Google Scholar 
    69.Wen, Y. et al. Cumulative effects of climatic factors on terrestrial vegetation growth. J. Geophys. Res.: Biogeosciences 124, 789–806 (2019).Article 
    ADS 

    Google Scholar 
    70.McKee, T. B., Doesken, N. J. & Kleist, J. in Proceedings of the 8th Conference on Applied Climatology. 179-183 (American Meteorological Society Boston, MA).71.Jiao, W., Tian, C., Chang, Q., Novick, K. A. & Wang, L. A new multi-sensor integrated index for drought monitoring. Agric. For. Meteorol. 268, 74–85 (2019).Article 
    ADS 

    Google Scholar  More

  • in

    A unifying model to estimate thermal tolerance limits in ectotherms across static, dynamic and fluctuating exposures to thermal stress

    Fitting tolerance time versus temperature to build a thermal death time curveThe high coefficients of determination found in the D. melanogaster TDT curves (Fig. 3A) are not uncommon and the exponential relation has consistently been found to provide a good fit of tolerance time vs. temperature in ectotherms3,15,20,22,23,24. Tolerance time vs. temperature data are also well fitted to Arrhenius plots which are based on thermodynamic principles (see for example15,36) and the absence of breakpoints in such plots provides a strong indication (but not direct proof) that the cause of coma/heat failure under the different intensities of acute heat stress is related to the same physiological process regardless whether failure occurs after 10 min or 10 h2,3 (but see “Discussion” section below). Despite the superior theoretical basis of Arrhenius analysis, we proceed with simple linear regressions of log10-transformed tcoma (TDT curve) as this analysis likewise provides a high R2 and is mathematically more straightforward. The physiological cause(s) of ectotherm heat failure are poorly understood37,38 but we argue that they are founded in a common process where heat injury accumulates at a temperature-dependent rate until a species-specific critical dose is attained (area below the curve and above Tc in Fig. 2). Thus, the organism has a fixed amount (dose) of thermally induced stress that it can tolerate before evoking the chosen endpoint. The experienced temperature of the animals then dictates the rate of which this stress is acquired, and accordingly when the endpoint is reached (Fig. 2) It is this reasoning that leads to TDT curves and explains why heat stress can be additive and thus also determines the boundaries of TDT curve modelling.Injury is additive across different stressful assay temperaturesIf heat stress acquired at intense and moderate stress within the span of the TDT curve acts through the same physiological mechanisms or converges to result in the same form of injury, then it is expected that injury is additive at different heat stress intensities. This hypothesis was tested by exposing flies sequentially to two static temperatures (different injury accumulation rates) and observe whether coma occurred as predicted from the summed injury (Fig. 2C). The accumulated heat injury at the two temperatures was found to be additive regardless of the order of temperature exposure (Fig. 3B,C). This finding is consistent with a conceptually similar study using speckled trout which also found strong support for additivity of heat stress at different stressful temperatures13. The exact physiological mechanism of heat injury accumulation is interesting to understand in this perspective, but it is not critical as long as the relation between temperature and injury accumulation rate is known.If injury accumulation is additive irrespective of the order of the heat exposure, we can extend the model to fluctuating temperature conditions. We have previously done this by accurately predicting dynamic CTmax from TDT parameters obtained from static assays for 11 Drosophila species (Fig. 6A, see “Discussion” section below and15). Here we extend this to temperature fluctuations that cannot be described by a simple mathematical ramp function. Specifically, groups of flies were subjected to randomly fluctuating temperatures and the observed tcoma was then compared to tcoma predicted using integration of heat injury based on TDT parameters (Fig. 4). The injury accumulation (Fig. 4C) was calculated by introducing the fluctuating temperature profiles in the associated R-script and the observed and predicted tcoma was found to correlate well (R2  > 0.94) across the 13 groups tested for each sex. These results further support the idea that injury is additive across a range of fluctuating and stressful temperatures and hence that similar physiological perturbations are in play during moderate and intense heat stress. It is important to note that in these experiments, temperatures fluctuated between 34.5 and 42.5 °C and accordingly the flies were never exposed to benign temperatures that could allow repair or hardening (see below).Figure 6adapted from Fig. 4b in15. (B) TDT parameters based on dCTmax from three dynamic tests were used to predict tcoma in static assays. Each point represents an observed vs. predicted value of species- and temperature-specific log10(tcoma). (Inset) Species values of the thermal sensitivity parameter z parameterized from TDT curves based on static assays (x-axis) or dynamic assays (y-axis). The dashed line represents the line of unity in all three panels.Conversion of heat tolerance measures between static and dynamic assays in Drosophila. Data from43. (A) Heat tolerance (dCTmax, d for dynamic assays) plotted against predicted dCTmax derived from species-specific TDT curves created from multiple (9–17) static assays. Data are presented for three different ramping rates (0.05, 0.1 and 0.25 °C min-1). Note that this graph is Full size imageIn conclusion, empirical data (present study;6,13,14,22) support the application of TDT curves to assess heat injury accumulation under fluctuating temperature conditions both in the lab and field for vertebrate and invertebrate ectotherms. Potential applications could be assessment of injury during foraging in extreme and fluctuating environments (e.g. ants in the desert39 or lizards in exposed habitat40) or for other animals experiencing extreme conditions41,42. The associated R-scripts allow assessment of percent lethal damage under such conditions if the model is provided with TDT parameters and information of temperature fluctuations (but see “Discussion” section of model limitations below).Model application for comparison of static versus dynamic dataThere is little consensus on the optimal protocol to assess ectotherm thermal tolerance and many different types of static or dynamic tests have been used to assess heat tolerance. TDT curves represent a mathematical and theoretical approach to reconcile different estimates of tolerance as the derived parameters can subsequently be used to assess heat injury accumulation at different rates (temperatures) and durations13,15,16. Here we provide R-scripts that enable such reconciliation and to demonstrate the ability of the TDT curves to reconcile data from static vs. dynamic assays we used published measurements of heat tolerance for 11 Drosophila species using three dynamic and 9–17 static measurements for each species43. Introducing data from only static assays we derived TDT parameters and subsequently used these to predict dynamic CTmax that were compared to empirically observed CTmax for three ramp rates (Fig. 6A). In a similar analysis, TDT parameters were derived from the three dynamic (ramp) experiments to predict tcoma at different static temperatures which were compared to empirical measures from static assays (Fig. 6B). Both analyses found good correlation between the predicted and observed values regardless whether the TDT curve was parameterized from static or dynamic experiments (Fig. 6). However, predictions from TDT curves based on three dynamic assays were characterised by more variation, particularly when used to assess tolerance time at very short or long durations. Furthermore, D. melanogaster and D. virilis which had the poorest correlation between predicted and observed tcoma in Fig. 6B had values of z from the TDT curves based on dynamic input data that were considerably different from values of z derived from TDT curves based on static assays (Fig. 6B inset). In conclusion TDT curves (and the associated R-scripts) are useful for conversion between static and dynamic assessment of tolerance. The quality of model output depends on the quality and quantity of data used as model input, and in this example the poorer model was parameterized from only three dynamic assays while the stronger model was based on 9–17 static assays (see also “Discussion” section below).Model application for comparison of published dataThermal tolerance is important for defining the fundamental niche of animals1,2,4 and the current anthropogenic changes in climate has reinvigorated the interest in comparative physiology and ecology of thermal limits in ectotherms. Meta-analyses of ectotherm heat tolerance data have provided important physiological, ecological and evolutionary insights5,44,45,46, but such studies are often challenged with comparison of tolerance estimates obtained through very different methodologies.Species tolerance is likely influenced by acclimation, age, sex, diet, etc.47 and also by the endpoint used (onset of spasms, coma, death, etc.27). Nevertheless, we expected heat tolerance of a species to be somewhat constrained45, so here we tested the model by converting literature data for nine species to a single and species-specific estimate of tolerance, sCTmax (1 h), the temperature that causes heat failure in 1 h (Fig. 5). The overwhelming result of this analysis is that TDT parameters are useful to convert static and dynamic heat tolerance measures to a single metric, and accordingly, the TDT model and R-scripts presented here have promising applications for large-scale comparative meta-analyses of ectotherm heat tolerance where a single metric allows for qualified direct comparison of results from different publications and experimental backgrounds. While this is an intriguing and powerful application, we caution that careful consideration should be put into the limitations of this model (see “Discussion” section below).Practical considerations and pitfalls for model interpretationAs shown above it is possible to convert and reconcile different types of heat tolerance measures using TDT parameters and these parameters can also be used to model heat stress under fluctuating field conditions. Modelling and discussion of TDT predictions beyond the boundaries of the input data has recently gained traction (see examples in48,49) but we caution that the potent exponential nature of the TDT curve requires careful consideration as it is both easy and enticing to misuse this model.Input dataThe quality of the model output is dictated by the input used for parameterization. Accordingly, we recommend TDT parameterization using several ( > 5) static experiments that should cover the time and temperature interval of interest, e.g. temperatures resulting in tcoma spanning 10 min to 10 h, thus covering both moderate and intense heat exposure. Such an experimental series can verify TDT curve linearity and allows modelling of temperature impacts across a broad range of temperatures and stress durations13,15,22. It is tempting to use only brief static experiments (high temperatures) for TDT parameterization, but in such cases, we recommend that the resulting TDT curve is only used to describe heat injury accumulation under severe heat stress intensities. Thus, the thermal sensitivity factor z represents a very powerful exponential factor (equivalent to Q10 = 100 to 100,000;15) which should ideally be parametrized over a broad temperature range (see below). We also include a script that allows TDT parametrization from multiple ramping experiments and again we recommend a broad span of ramping rates to cover the time/temperature interval of interest. A drawback of ramping experiments is the relatively large proportion of time spent at benign temperatures where there is no appreciable heat injury accumulation. Thus, dynamic experiments can conveniently use starting temperatures that are close to the temperature where injury accumulation rate surpasses injury repair rate (see “Discussion” section of “true” Tc below, in Supplemental Information and19 for other considerations regarding ramp experiments).A final methodological consideration relates to body-temperature in brief static experiments where the animal will spend a considerable proportion of the experiment in a state of thermal disequilibrium (i.e. it takes time to heat the animal). To avoid this, we recommend direct measurement of body temperature (large animals) or container temperature (small animals), and advise against excessive reliance on data from test temperatures that results in coma in less than 10 min.ExtrapolationMost studies of ectotherm heat tolerance include only a single measure of heat tolerance which is inadequate to parameterize a TDT curve. However, a TDT curve can still be generated from a single measure of tolerance (static or dynamic) if a value of z is assumed (see Supplemental Information). As z differs within species and between phylogenetic groups (Table S115,20), choosing the appropriate value may be difficult and discrepancies between the ‘true’ and assumed z represent a problem that should be approached with care. In Fig. 7A we illustrate this point in a constructed example where a single heat tolerance measurement is sampled from a ‘true’ TDT curve (full line; tcoma = 40 min at 37 °C). Along with this ‘true’ TDT curve we depict the consequences for model predictions if the assumed value of z is misestimated by ± 50%. Extrapolation from the original data point is necessary if an estimate of the temperature that causes coma after 1 h is desired, however due to limited extrapolation (from 40 to 60 min), estimation of sCTmax (1 h) values based on the ‘true’ and z ± 50% are not very different ( 6 h) between heat exposure disrupted additivity, suggesting that injury is repaired at benign temperature50. Injury repair rate is largely understudied but repair rate is generally increasing with temperature51,52,53. It is therefore an intriguing and promising idea to include a temperature-dependent repair function in more advanced modelling of heat injury. Until such repair processes are introduced in the model, we recommend that additivity of heat injury is evaluated critically if it involves periods at temperatures both above and below Tc (i.e. over consecutive days, see also13). An alternative, but not mutually excluding, explanation of increased heat resilience in split-dose experiments relates to the contribution of heat hardening as it is likely that the first heat exposure in a series can induce hardening responses that increase resilience (and thus change the TDT parameters) when a second heat exposure occurs. Such issues of repeated thermal stress have been discussed previously54 but for the purpose of the present study the main conclusion is that simple TDT curve modelling is not applicable to fluctuations bracketing Tc unless this is empirically validated. Future studies could address this issue as inclusion of repair functions would add further promise to the use of TDT curves in modelling of the impacts of temperature fluctuations. More

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    Photoacclimation by phytoplankton determines the distribution of global subsurface chlorophyll maxima in the ocean

    Physical modelThe physical part of the model is a global Oceanic General Circulation Model, Meteorological Research Institute Community Ocean Model version 3 (MRI.COM3)40. The model has horizontal resolutions of 1° in longitude and 0.5° in latitude south of 64° N, and tripolar coordinates are applied north of 64° N. The model is discretized in 51 vertical layers. In the upper 160 m, tracers are calculated at depths of 2.0, 6.5, 12.25, 19.25, 27.5, 37.75, 50.5, 65.5, 82.25, 100.0, 118.2, 137.5, and 157.75 m, and therefore vertical variation in chlorophyll concentration below the grid-scale is not represented in our model. The model was forced with realistic wind stress, surface heat and freshwater fluxes40.Marine ecosystem modelWe developed a marine ecosystem model composed of phytoplankton, zooplankton, nitrate, ammonia, particulate organic nitrogen, dissolved organic nitrogen, dissolved iron (Fed), and particulate iron. Our model is a 3D version of the FlexPFT model27 and is called the FlexPFT-3D model. The main changes of the FlexPFT-3D from original FlexPFT model are the introduction of iron limitation and substitution of the carbon-based phytoplankton biomass in the original with nitrogen-based biomass herein. The iron cycle is based on the nitrogen-, silicon- and iron-regulated Marine Ecosystem Model41 including the process of scavenging and iron input from dust and sediment. Dissolved iron starts from the distribution calculated by the Biological Elemental Cycling model in Misumi et al.42. Nitrate starts from the distribution of World Ocean Database 199843. After the connection of the physical model, a 20 years of historical simulation (1985–2004) is performed. In addition to the standard case with the chlorophyll-specific initial slope of growth versus irradiance, aI, of 0.35 m2 E−1 mol C (g chl)−1, the case studies with aI of 0.5 and 1.0 m2 E−1 mol C (g chl)−1 were implemented. The case studies are calculated from 2003 to 2004, starting from the distributions of biological variables at the end of 2002 in the standard case.Phytoplankton growthThe procedures of numerical integration of phytoplankton concentration are described here. Readers can construct a numerical model using the following equations. The derivations of the following equations from theories are presented by Smith et al.27 (hereafter Smith2016). Values of biological parameters are described in Supplementary Table 1.In accordance with Pahlow’s resource allocation theory28, the FlexPFT model assumes that resources are allocated among structural material, nutrient uptake and, light harvesting (Supplementary Fig. 1a). The fraction of structural material is assumed to be Qs/Q, where Q is the nitrogen cell quota, which is the intracellular nitrogen to carbon ratio (mol N mol C−1), and Qs is the structural cell quota (mol N mol C−1) given as a fixed parameter. The fraction of nutrient uptake is defined as fV (non-dimensional), so that the residual fraction available for light-harvesting is equal to ((1-frac{{Q}_{{rm{s}}}}{Q}-{f}_{{rm{v}}})). Optimal uptake kinetics further sub-divides the resources allocated to nutrient uptake between surface uptake sites (affinity) and enzymes for assimilation (maximum uptake rate), the fraction of which is given by fA and (1 − fA), respectively. Under nutrient-deficient conditions, the number of surface uptake sites (and hence affinity) increases, while enzyme concentration (hence, maximum uptake rate) decreases. The FlexPFT model assumes instantaneous resource allocation, which means that resource allocation tracks temporal environmental change with no lag time. It has elsewhere been demonstrated that an instantaneous acclimation model provides an accurate approximation of a fully dynamic acclimation model44.We assume that acclimation responds to daily-averaged environmental conditions, which are used to calculate the optimal values of fV, fA, and Q as ({f}_{V}^{o}), ({f}_{A}^{o}), and ({Q}^{o}). The optimal values are estimated at the beginning of a day and are retained for the following 24 h. The daily-averaged environmental variables of the seawater temperature, T (°C), intensity of photosynthetically active radiation, I, nitrogen concentration, [N], which is the sum of nitrate and ammonia concentrations, and dissolved iron concentration, [Fed] are defined as (bar{T}), (bar{I}), ([bar{{rm{N}}}]), and ([{overline{{rm{Fe}}}}_{{rm{d}}}]), respectively. Based on the assumption that diurnal variation of temperature and nutrient are very small, T, [N] and [Fed] at the beginning of a day are used as (bar{T}), ([bar{{rm{N}}}]), and ([{overline{{rm{Fe}}}}_{{rm{d}}}]), respectively. For (bar{I}), we use the average in sunshine duration in a day, which is slightly modified from the daily average in Smith2016.Phytoplankton growth rate per unit carbon biomass (day−1), μ, is given by$$mu ={hat{mu }}^{I}left(1-frac{{Q}_{{rm{s}}}}{{Q}^{o}}-{f}_{V}^{o}right)-{zeta }^{N}{f}_{V}^{o}{hat{V}}^{N},$$
    (1)
    where ({hat{mu }}^{I}) is the potential carbon fixation rate per unit carbon biomass (day−1), ({zeta }^{N}) is the energetic respiratory cost of assimilating inorganic nitrogen (0.6 mol C mol N−1), and ({hat{V}}^{N}) is the potential nitrogen uptake rate per unit carbon biomass (mol N mol C−1 day−1). Equation (1) represents the balance of net carbon fixation and respiration costs of nitrogen uptake, which are proportional to the fraction of resource allocation. ({hat{V}}^{N}([bar{{rm{N}}}],,bar{T})) is$${hat{V}}^{N}([bar{{rm{N}}}],bar{T})=frac{{hat{V}}_{0}[bar{{rm{N}}}]}{(frac{{hat{V}}_{0}}{{hat{A}}_{0}})+2sqrt{frac{{hat{V}}_{0}[bar{{rm{N}}}]}{{hat{A}}_{0}}}+[bar{{rm{N}}}]},$$
    (2)
    where ({hat{A}}_{0}) and ({hat{V}}_{0}) are the maximum value of affinity and maximum nitrogen uptake rate.From here, we will explain how the optimized values such as ({f}_{V}^{o}), ({f}_{A}^{o}), and ({Q}^{o}) are calculated. The optimal fraction of resource allocation to affinity, ({f}_{A}^{o}), is given by$${f}_{A}^{o}={[1+sqrt{frac{{hat{A}}_{0}[bar{{rm{N}}}]}{F(bar{T}){hat{V}}_{0}}}]}^{-1},$$
    (3)
    which is derived by substituting Eqs. (18) and (19) in Smith2016 into Eq. (17). (F(bar{T})) is temperature dependence, defined as$$F(bar{T})=exp {-frac{{E}_{a}}{R}[frac{1}{bar{T}+298}-frac{1}{{T}_{{rm{ref}}}+298}],},$$
    (4)
    where Ea is the parameter of the activation energy of 4.8 × 104 J mol−1, R is the gas constant of 8.3145 J (mol K)−1, and Tref is the reference temperature of 20 °C.Optimization for light-harvesting is described below. The potential carbon fixation rate per unit carbon biomass (day−1), ({hat{mu }}^{I},)(day−1), in Eq. (1) is$${hat{mu }}^{I}(bar{I},bar{T},[{overline{{rm{Fe}}}}_{{rm{d}}}])={hat{mu }}_{0}frac{[{overline{{rm{Fe}}}}_{{rm{d}}}]}{[{overline{{rm{Fe}}}}_{{rm{d}}}]+{k}_{{rm{Fe}}}}S(bar{I},bar{T},[{overline{{rm{Fe}}}}_{{rm{d}}}])F(bar{T}),$$
    (5)
    where ({hat{mu }}_{0}) and kFe are the maximum carbon fixation rate and half saturation constant for iron, respectively. S specifies the dependence of light. Defining ({hat{mu }}_{0}^{{rm{limFe}}}={hat{mu }}_{0}frac{[{overline{{rm{Fe}}}}_{{rm{d}}}]}{[{overline{{rm{Fe}}}}_{{rm{d}}}]+{k}_{{rm{Fe}}}}),$${hat{mu }}^{I}(bar{I},bar{T},[{overline{{rm{Fe}}}}_{{rm{d}}}])={hat{mu }}_{0}^{{rm{limFe}}}S(bar{I},bar{T},[{overline{{rm{Fe}}}}_{{rm{d}}}],)F(bar{T}).,$$
    (6)
    Iron limitation is imposed by substituting ({hat{mu }}_{0}) to ({hat{mu }}_{0}^{{rm{limFe}}}) in all equations in Smith2016. S is defined as$$S(bar{I},bar{T},[{overline{{rm{Fe}}}}_{{rm{d}}}],)=1-exp {frac{-{a}_{I}{hat{Theta }}^{o}bar{I}}{{hat{mu }}_{0}^{{rm{limFe}}}F(bar{T})}},$$
    (7)
    where ({a}_{I}) is the chlorophyll-specific initial slope of growth versus irradiance. ({hat{Theta }}^{o}), optimal chloroplast chl:phyC (g chl (mol C)−1), is$${hat{Theta }}^{o} = ; frac{1}{{zeta }^{{rm{chl}}}}+frac{{hat{mu }}_{0}^{{rm{limFe}}}}{{a}_{I}bar{I}}{1-{W}_{0}[(1+frac{{R}_{M}^{{rm{chl}}}}{{L}_{{rm{d}}}{hat{mu }}_{0}^{{rm{limFe}}}})exp (1+frac{{a}_{I}bar{I}}{{zeta }^{{rm{chl}}}{hat{mu }}_{0}^{{rm{limFe}}}}),],},(bar{I} > {I}_{0})\ {hat{Theta }}^{o} = ; 0,(bar{I}le {I}_{0}),$$
    (8)
    where constant parameters ({{rm{zeta }}}^{{rm{chl}}}) and ({R}_{M}^{{rm{chl}}}) are the respiratory cost of photosynthesis (mol C (g chl)−1) and the loss rate of chlorophyll (day−1), respectively. Ld is the fractional day length in 24 h. W0 is the zero-branch of Lambert’s W function. I0 is the threshold irradiance below which the respiratory costs overweight the benefits of producing chlorophyll:$${I}_{0}=frac{{zeta }^{{rm{chl}}}{R}_{M}^{{rm{chl}}}}{{L}_{{rm{d}}}{a}_{I}}.,$$
    (9)
    The optimal fraction of resource allocation to nutrient uptake, ({f}_{V}^{o}), is$${f}_{V}^{o}=frac{{hat{mu }}^{I}(bar{I},bar{T},[{overline{{rm{Fe}}}}_{{rm{d}}}]){Q}_{{rm{s}}}}{{hat{V}}^{N}([bar{{rm{N}}}],bar{T})}[-1+sqrt{{[{Q}_{{rm{s}}}(frac{{hat{mu }}^{I}(bar{I},bar{T},[{overline{{rm{Fe}}}}_{{rm{d}}}])}{{hat{V}}^{N}([bar{{rm{N}}}],bar{T})}+{zeta }^{N})]}^{-1}+1},]$$
    (10)
    The optimal nitrogen cell quota, ({Q}^{o}) is$${Q}^{o}={Q}_{{rm{s}}}[1+sqrt{1+{[{Q}_{{rm{s}}}(frac{{hat{mu }}^{I}(bar{I},bar{T},[{overline{{rm{Fe}}}}_{{rm{d}}}])}{{hat{V}}^{N}([bar{{rm{N}}}],bar{T})}+{zeta }^{N})]}^{-1}},]$$
    (11)
    Optimal cellular chl:phyC (g chl (mol C)−1), ({Theta }^{o}), is$${Theta }^{o}=(1-frac{{Q}_{{rm{s}}}}{{Q}^{o}}-{f}_{V}^{o}){hat{Theta }}^{o}$$
    (12)
    which is the multiplication of the fraction of resource allocation to light-harvesting and optimal chloroplast chl:phyC. The cellular chl:phyC and chloroplast chl:phyC in Figs. 1 and 2 are optimal cellular chl:phyC, ({Theta }^{o}), and optimal chloroplast chl:phyC, ({hat{Theta }}^{o}), respectively. The relation in Eq. (12) is displayed in Fig. 1i-n. If we artificially turn off the optimization of resource allocation by applying the constant ({Q}^{o}) and ({f}_{V}^{o}) to the all grid points, optimal cellular chl:phyC (Fig. 1i,j) only depends on optimal chloroplast chl:phyC (Fig. 1k, l), and therefore significant variation of SCM depth across the equatorial, subtropical, and subpolar regions is not reproduced.In the above equations, Eqs. (3), (8), (10), (11), and (12), optimized values related to acclimation processes are obtained and then used in calculating the phytoplankton growth rate. Phytoplankton growth rate per unit carbon biomass (day−1), (mu), in Eq. (1) is calculated at each time step:$$mu (I,T,[{rm{N}}],[{{rm{Fe}}}_{{rm{d}}}])=frac{{hat{mu }}^{I}(I,T,[{{rm{Fe}}}_{{rm{d}}}]){f}_{V}^{o}(1-{f}_{A}^{o}){hat{V}}_{0}{f}_{A}^{o}{hat{A}}_{0}[{rm{N}}]}{{hat{mu }}^{I}(I,T,[{{rm{Fe}}}_{{rm{d}}}]){Q}_{0}(1-{f}_{A}^{o}){hat{V}}_{0}+({hat{mu }}^{I}(I,T,[{{rm{Fe}}}_{{rm{d}}}]){Q}_{0}+{f}_{V}^{o}(1-{f}_{A}^{o}){hat{V}}_{0}){f}_{A}^{o}{hat{A}}_{0}[{rm{N}}]},$$
    (13)
    where ({hat{mu }}^{I}(I,,T,,[{{rm{Fe}}}_{{rm{d}}}])) is obtained by substituting I, T, and [Fed] for (bar{I}), (bar{{rm{T}}}), and ([{overline{{rm{Fe}}}}_{{rm{d}}}]) in Eq. (5), respectively. Note that the model calculates circadian variation in solar irradiance, I, and therefore the phytoplankton growth rate, μ, reaches its maximum at noon local time and is zero during night. On the other hand, phytoplankton optimization is assumed to respond to daily-averaged conditions. The FlexPFT model introduces phytoplankton respiration proportional to chlorophyll content, which is another important originality of Pahlow’s resource allocation theory30,33.The carbon biomass-specific respiratory costs of maintaining chlorophyll, Rchl, is$${R}^{{rm{chl}}}(I,T,[{rm{N}}],[{{rm{Fe}}}_{{rm{d}}}])=({hat{mu }}^{I}(I,T,[{{rm{Fe}}}_{{rm{d}}}])+{R}_{M}^{{rm{chl}}}){{rm{zeta }}}^{{rm{chl}}}{Theta }^{o}.,$$
    (14)
    The growth rate per unit nitrogen biomass, ({mu }_{{rm{N}}}), is equal to that per unit carbon biomass, μ. Instantaneous acclimation assumes that the quota of nitrogen to carbon biomass obtained by phytoplankton growth is equal to the nitrogen quota in a cell: (frac{{mu }_{{rm{N}}}[{{rm{p}}}^{{rm{N}}}]}{mu [{{rm{p}}}^{{rm{C}}}]}={Q}^{o}), where [pC] and [pN] are phytoplankton carbon and nitrogen concentration in a cell, respectively. Since (frac{[{{rm{p}}}^{{rm{N}}}]}{[{{rm{p}}}^{C}]}={Q}^{o}), ({mu }_{{rm{N}}}=mu). When temporal ({Q}^{o}) change occurs, to satisfy the mass conservation, carbon or nitrogen biomass is adjusted with the other fixed. The FlexPFT fixes carbon biomass, while the FlexPFT-3D fixes nitrogen biomass to the temporal ({Q}^{o}) change.The rate of change in the phytoplankton nitrogen concentration, [pN], except for the advection and diffusion terms is given by the following equation:$$frac{partial [{{rm{p}}}^{{rm{N}}}]}{partial t}=mu [{{rm{p}}}^{{rm{N}}}]-({R}^{{rm{chl}}}+{R}^{{rm{cnst}}})[{{rm{p}}}^{{rm{N}}}]-{M}_{{rm{p}}}{[{{rm{p}}}^{{rm{N}}}]}^{2}-({rm{extracellular}},{rm{excretion}})-({rm{grazing}}),$$
    (15)
    where Rcnst and Mp are the coefficient of respiration not related to chlorophyll concentration and mortality rate coefficient, respectively. The extracellular excretion is$$({rm{extracellular}},{rm{excretion}})={gamma }_{{rm{ex}}}[(mu -{R}^{{rm{chl}}})[{{rm{p}}}^{{rm{N}}}]],$$
    (16)
    where ({gamma }_{{rm{ex}}}) is the coefficient of extracellular excretion. The grazing term is represented by$$({rm{grazing}})={G}_{20deg }F(T)[{{rm{z}}}^{{rm{N}}}]frac{{[{{rm{p}}}^{{rm{N}}}]}^{{a}_{{rm{H}}}}}{{({k}_{{rm{H}}})}^{{a}_{{rm{H}}}}+{[{{rm{p}}}^{{rm{N}}}]}^{{a}_{{rm{H}}}}},$$
    (17)
    where G20deg is the maximum grazing rate at 20 °C, and [zN] is zooplankton concentration. Temperature dependency, F(T), is obtained by substituting T for (bar{T}) in Eq. (4). ({a}_{{rm{H}}}) is the parameter controlling Holling-type grazing, which takes a value from 1 to 2. kH is the grazing coefficient in Holling-type grazing.Once [pN] is calculated, phytoplankton carbon concentration (mol C L−1), and chlorophyll concentration (g chl L−1) are uniquely determined in an environmental condition, without prognostic calculation. Therefore, an instantaneous acclimation model can represent stoichiometric flexibility with lower computational costs compared with a dynamic acclimation model44.Model validationThe spatial pattern of simulated annually mean chlorophyll at the ocean surface agrees with that of satellite observation45 (Supplementary Fig. 3). The model reproduced the contrast of the surface chlorophyll concentration between subtropical and subpolar regions, although simulated surface chlorophyll concentration in subtropical regions is lower than that of the observation partly due to the lack of nitrogen fixers. Nitrogen fixation is estimated to support about 30–50% of carbon export in subtropical regions46,47. Simulated surface chlorophyll distribution in the Pacific equatorial region is close to the observed.Our model properly simulates the meridional distribution of nitrate compared with that of observations48 (Supplementary Fig. 4). The simulated horizontal distribution of primary production is consistent with that estimated by satellite data9,49 (Supplementary Fig. 5), although simulated primary production is underestimated in subtropical regions, associated with the underestimation of surface chlorophyll in these regions (Supplementary Fig. 3). More

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    The extracellular contractile injection system is enriched in environmental microbes and associates with numerous toxins

    eCIS are encoded by 1.9% and 1.2% of sequenced bacteria and archaea, respectively, with a highly biased taxonomic distributionFirst, we were interested in identifying all eCIS loci in a large genomic dataset. We compiled a set of 64,756 microbial isolate genomes retrieved from Integrated Microbial Genomes (Supplementary Data 1)16. To identify core component homologs from known systems, we searched for genes with known eCIS-associated pfam annotations (Supplementary Table 1). To supplement this, we also annotated homologous genes ourselves by searching using the Hidden Markov Model (HMM) profiles from a recent publication1,17. We defined putative eCIS operons as gene cassettes that included these multiple eCIS core genes in close proximity and were not bacteriophage, T6SS, or R-type pyocins (Supplementary Table 1, Methods). Overall, we identified eCIS operons encoded in 1230 (1.9%) bacteria and 19 (1.2%) archaea from our genomic repository (Supplementary Data 2–3). We identified two core genes, Afp8 and Afp11, that co-occur in eCIS operons across 98.7% of loci and used their protein sequences to construct an eCIS phylogenetic gene tree (Fig. 1a, Supplementary Figs. 2–3, Supplementary Data 4). Afp8 and Afp11 alone resulted in phylogenetically similar trees (Supplementary Fig. 4) and the trees agree with eCIS division into subtype I and II that were defined in a previous eCIS analysis17 (Supplementary Fig. 5). eCIS is scattered across the prokaryotic diversity with presence in 14 bacterial phyla and one archaeal phylum. The incongruence between this tree and the genomic phylogeny suggests that eCIS undergo HGT frequently, as was proposed before1,17. The previously experimentally characterized eCISs are located within a narrow clade on the eCIS tree, pointing to the possibility that other eCIS particles may play more diverse ecological roles (Fig. 1a, Supplementary Fig. 2).Fig. 1: Taxonomic Distribution of eCIS-encoding microbes.a A phylogenetic tree of eCIS across the microbial world. eCIS core genes Afp8 and Afp11 from each operon were concatenated, aligned, and used to construct the phylogenetic tree. The Domain and Phylum corresponding to each leaf are indicated in the inner and outer rings, respectively. Scaffolds encoding eCIS that have been predicted to be plasmids using Deeplasmid were marked with black triangles. Previously experimentally investigated eCIS are marked on their respective leaves (2 o’clock). Within the tree MACS, AFP, and PVC are abbreviations for Metamorphosis-associated Contractile Structures, Antifeeding Prophage, and Photorhabdus Virulence Cassettes. b eCIS distribution in different genera. We calculated the eCIS distribution across genera using a Fisher exact test. The Odds Ratio represents the enrichment or depletion magnitude, with hotter colors representing enrichment, and colder colors representing depletion. Calculated p values were corrected for multiple testing using FDR to yield minus log10 q values, shown in shades of gray. Only selected Genera are shown. Source data are provided in Supplementary Data 1–2,5–6.Full size imageNext, we looked for genetic mechanisms that may mediate the eCIS HGT. Using Deeplasmid, a new plasmid prediction tool that we developed18, we identified that 7.6% of eCIS are likely plasmid-borne (Fig. 1a and Supplementary Fig. 6, Supplementary Data 5, Methods). In other cases, we found a clear signature of eCIS operon integration into a specific bacterial chromosome (Supplementary Fig. 7). For example, we identified a likely homologous recombination event between identical tRNA genes, a classical integration site19 (Supplementary Fig. 7b). These genomic integration events and the plasmid-borne eCIS operons shed light on the mechanisms through which eCIS loci have been horizontally propagated in microbial genomes.eCIS displays a highly biased taxonomic distributionGiven the propensity of eCIS to transfer between microbes as phylogenetically distant as bacteria and archaea, we were surprised by its scarcity in microbial genomes. We tested if eCIS loci are homogeneously distributed across microbial taxa and found that eCIS are mostly constrained to particular taxa (Fig. 1b, Supplementary Data 6). Strikingly, we found that it is present in 100% (18/18) of Photorhabdus genomes in our dataset (Fisher exact test, odds ratio = infinity, q value = 2.97e−28), 89% of sequenced Chitinophaga (odds ratio = 276, q value = 1.69e−35), 86% of sequenced Dickeya (odds ratio = 211, q value = 3.78e−18), and 69% of sequenced Algoriphagus (odds ratio = 73, q value = 1.99e−24). These genera are known as environmental microbes; Photorhabdus is a commensal of entomopathogenic nematodes20, Chitinophaga is a soil microbe and a fungal endosymbiont21, Dickeya is a plant and pea aphid pathogen22,23, and Algoriphagus is an aquatic or terrestrial microbe24,25,26,27,28. In contrast, eCIS is strongly depleted from the most cultured and sequenced genera of Gram-positive and negative human pathogens, including Staphylococcus, Escherichia, Salmonella, Streptococcus, Acinetobacter, and Klebsiella. Strikingly, within these genera, for which our repository had 18,355 genomes, eCIS was totally absent (odds ratio = 0, q value ≤ 3.86E-16 for each one of these genera), suggesting a very potent purifying selection acting against eCIS integration into these microbial genomes, despite the eCIS operons’ tendency for extensive lateral transfer and its presence in other host-associated systems. Interestingly, 146 genomes, mostly from Photorhabdus, Dickeya, Actinokineospora, Streptomyces, Algoriphagus, Chitinophaga, Flavobacterium, and Calothrix genera, were found to contain more than one eCIS operon, ranging from 2 to 5 copies per genomes (Supplementary Data 7).eCIS presence is highly correlated with specific ecosystems, microbial lifestyles, and microbial hostsGiven the strong eCIS taxonomic bias we identified, we were curious to know if we could further associate eCIS with specific ecological features. To this end, we retrieved metadata available for all sequenced genomes in our repository (Methods). These traits include the microbial isolation site, ecosystem and habitat, microbial lifestyle and physiology, and the organisms hosting the microbes (Supplementary Data 8). We calculated the correlation of eCIS presence with certain microbial traits to identify significant enrichment and depletion patterns. This was done using a naïve enrichment test (Fisher exact test) together with a phylogeny-aware test, Scoary29, which is used to correct for the phylogenetic bias of the isolate genomes. Using this test we quantify to what extent the eCIS presence in a genome correlates with a certain trait, independently of the microbial phylogeny (Fig. 2, Supplementary Fig. 8). Notably, eCIS is positively correlated with terrestrial and aquatic environments, such as soil, sediments, lakes, and coasts, but is depleted from food production venues. In terms of microbial lifestyle and physiology, eCISs are enriched in environmental microbes, mostly symbiotic, and are depleted from pathogens (the vast majority of which were isolated from humans). eCISs are enriched in aerobic microbes that dwell in mild and cold temperatures. In general, the eCIS-encoding microbes tend to associate with terrestrial hosts including insects, nematodes, annelids, protists, fungi, and plants, and in aquatic hosts such as fish, sponges, and molluscs. Intriguingly, we detected a strong depletion from bacteria that were isolated from birds and mammals, including humans. We did find some eCIS isolated from bacteria associated with humans, but sparse and statistically depleted (Supplementary Fig. 8). Looking closer we also see that the operon is depleted from all tissues in which the human microbiome is abundant: oral and digestive systems, skin, and the urogenital tract. However, we detected a mild eCIS enrichment in the human gut commensal Bacteroides (Fig. 1b) and Parabacteroidetes genera. Bacteroides was recently reported by the Shikuma group as being eCIS-rich30.Fig. 2: eCIS-encoding microbes’ lifestyle and isolation.A Fisher exact test combined with a modified version of Scoary was used to perform a phylogeny-aware analysis of eCIS-encoding microbes’ metadata. The Odds Ratio represents the enrichment or depletion magnitude, with hotter colors representing enrichment, and colder colors representing depletion. The negative log10 of the q-values, shown in shades of gray, are corrected for multiple hypothesis testing. One q-value corresponds to the statistical significance of a two-sided Fisher exact test, and the other represents the same for the Scoary pairwise comparison test. Source Data are provided in Supplementary Data 8.Full size imageWe also see that eCIS is clearly associated with larger bacterial genomes in five bacterial phyla (Supplementary Fig. 9), although small genome endosymbionts are found to contain eCIS as well, for example, the Candidatus Regiella insecticola LSR1, which harbours an eCIS even though its genome size is ~2 Mbps and it contains 10 is defined “Core”, 4–10 is “Shell”, More