Combined effects of CO2 and temperature on carbon uptake and partitioning by the marine diatoms Thalassiosira weissflogii and Dactyliosolen fragilissimus
Combined effects of CO2 and temperature on carbon uptake and partitioning by the marine diatoms Thalassiosira weissflogii and Dactyliosolen fragilissimus
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DOI：
10.1002/lno.10063
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发表时间：
2015-05
影响因子：
4.5
通讯作者：
J. Taucher;J. Jones;A. James;M. Brzezinski;C. Carlson;U. Riebesell;U. Passow
中科院分区：
文献类型：
--
作者：
J. Taucher;J. Jones;A. James;M. Brzezinski;C. Carlson;U. Riebesell;U. Passow
在4种条件下（15°C，400 μatm），研究了两种全球丰富的硅藻物种--威氏海链藻（Thalassiosira weissflopulum）和脆弱指管藻（Dactyliosolen fragilissimus）的碳吸收和分配：环境温度（15 °C，1000 μatm）、高温（20°C，400 μatm）和混合温度（20°C，1000 μatm）。实验从指数增长进入稳定期（氮耗尽后6天），使我们能够跟踪类似于海洋中水华情况的生物地球化学动力学。CO2浓度升高对T. weissfloprotein和D.最脆弱的这也反映在更高的细胞数量，颗粒和溶解有机物的积聚以及透明的外聚合物颗粒中。CO2的影响是最突出的稳定期时，氮耗尽和CO2（aq）浓度低。这表明，硅藻在高CO2处理可以采取更多的DIC，直到海水中的CO2浓度变得如此之低，碳限制发生。这些结果表明，与通常的假设相反，硅藻可能对海洋碳酸盐化学的持续变化非常敏感，特别是在营养限制下。从15 ° C到20 °C的变暖对一个物种有刺激作用，但对另一个物种来说是一种压力源，突出了物种特异性生理最佳状态和温度范围在应对海洋变暖中的重要性。总体而言，这些对二氧化碳和温度的敏感性可能会对硅藻水华和生物泵产生深远影响。
Carbon uptake and partitioning of two globally abundant diatom species, Thalassiosira weissflogii and Dactyliosolen fragilissimus, was investigated in batch culture experiments under four conditions: ambient (15°C, 400 μatm), high CO2 (15°C, 1000 μatm), high temperature (20°C, 400 μatm), and combined (20°C, 1000 μatm). The experiments were run from exponential growth into the stationary phase (six days after nitrogen depletion), allowing us to track biogeochemical dynamics analogous to bloom situations in the ocean. Elevated CO2 had a fertilizing effect and enhanced uptake of dissolved inorganic carbon (DIC) by about 8% for T. weissflogii and by up to 39% for D. fragilissimus. This was also reflected in higher cell numbers, build‐up of particulate and dissolved organic matter, and transparent exopolymer particles. The CO2 effects were most prominent in the stationary phase when nitrogen was depleted and CO2(aq) concentrations were low. This indicates that diatoms in the high CO2 treatments could take up more DIC until CO2 concentrations in seawater became so low that carbon limitation occurs. These results suggest that, contrary to common assumptions, diatoms could be highly sensitive to ongoing changes in oceanic carbonate chemistry, particularly under nutrient limitation. Warming from 15 to 20 °C had a stimulating effect on one species but acted as a stressor on the other species, highlighting the importance of species‐specific physiological optima and temperature ranges in the response to ocean warming. Overall, these sensitivities to CO2 and temperature could have profound impacts on diatoms blooms and the biological pump.