Biodiversity and Stoichiometric Plasticity Increase Pico‐Phytoplankton Contributions to Marine Net Primary Productivity and the Biological Pump
Biodiversity and Stoichiometric Plasticity Increase Pico‐Phytoplankton Contributions to Marine Net Primary Productivity and the Biological Pump
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DOI：
10.1029/2023gb007756
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发表时间：
2023-07
影响因子：
5.2
通讯作者：
R. Letscher;J. Moore;A. Martiny;M. Lomas
中科院分区：
文献类型：
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作者：
R. Letscher;J. Moore;A. Martiny;M. Lomas
地球系统模式一般预测，21世纪变暖将导致上层海洋分层增加，这将导致垂直养分通量减少，迫使海洋净初级生产力（NPP）和碳输出下降。海洋生态系统碳-营养化学计量计量的最新进展已经确定了巨大的纬度和生物群系变异性，低纬度寡营养系统中窝养的微型浮游植物表现出较大的磷-碳细胞可塑性。因此，气候强迫的营养物通量化学计量和浮游植物群落组成的变化可能改变海洋生物地球化学对碳-气候系统的响应和反馈。我们在群落地球系统模型的生物地球化学元素循环组件中增加了三种微型浮游植物功能类型，同时为所有代表的浮游植物类型纳入了可变细胞磷碳化学计量学。该模型模拟了主导热带和亚热带海洋生产力和下沉碳输出的原绿球藻和聚球菌种群，以及在亚热带到中纬度过渡区内对生产力和输出有重要贡献的微真核生物种群，其中每个盆地的亚热带西部地区支持最贫P -化学计量学。副热带环流再环流区域沿表层西边界流的极侧被确定为碳输出增强的区域热点，表现出富C /贫P的化学计量特征，优先栖息于微真核生物和硅藻。总的来说，微型浮游植物通过直接和生态系统处理途径贡献了全球NPP的58%和全球100米以下颗粒有机碳输出的46%。海洋微型浮游植物的生物多样性和细胞营养可塑性共同增加了它们对海洋生产力和生物碳泵的贡献。
Earth System Models generally predict increasing upper ocean stratification from 21st century warming, which will cause a decrease in the vertical nutrient flux forcing declines in marine net primary productivity (NPP) and carbon export. Recent advances in quantifying marine ecosystem carbon to nutrient stoichiometry have identified large latitudinal and biome variability, with low‐latitude oligotrophic systems harboring pico‐sized phytoplankton exhibiting large phosphorus to carbon cellular plasticity. The climate forced changes in nutrient flux stoichiometry and phytoplankton community composition are thus likely to alter the ocean's biogeochemical response and feedback with the carbon‐climate system. We have added three pico‐phytoplankton functional types within the Biogeochemical Elemental Cycling component of the Community Earth System Model while incorporating variable cellular phosphorus to carbon stoichiometry for all represented phytoplankton types. The model simulates Prochlorococcus and Synechococcus populations that dominate the productivity and sinking carbon export of the tropical and subtropical ocean, and pico‐eukaryote populations that contribute significantly to productivity and export within the subtropical to mid‐latitude transition zone, with the western subtropical regions of each basin supporting the most P‐poor stoichiometries. Subtropical gyre recirculation regions along the poleward flanks of surface western boundary currents are identified as regional hotspots of enhanced carbon export exhibiting C‐rich/P‐poor stoichiometry, preferentially inhabited by pico‐eukaryotes and diatoms. Collectively, pico‐phytoplankton contribute ∼58% of global NPP and ∼46% of global particulate organic carbon export below 100 m through direct and ecosystem processing pathways. Biodiversity and cellular nutrient plasticity in marine pico‐phytoplankton combine to increase their contributions to ocean productivity and the biological carbon pump.