Impact of CO2 on the elemental composition of the particulate and dissolved organic matter of marine diatoms emerged after nitrate depletion
Impact of CO2 on the elemental composition of the particulate and dissolved organic matter of marine diatoms emerged after nitrate depletion
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DOI：
10.1002/lno.10816
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发表时间：
2018-09
影响因子：
4.5
通讯作者：
K. Sugie;T. Yoshimura;M. Wakita
中科院分区：
文献类型：
--
作者：
K. Sugie;T. Yoshimura;M. Wakita
虽然溶解的无机碳浓度，pH值和营养盐的海水制度显着变化在沿海地区，在CO2和营养水平的变化对硅藻产生的颗粒和溶解有机物（DOM）的元素动态的协同效应很少被调查。在这里，我们研究了四种不同的CO2水平（180，380，600和1000 μatm的CO2分压：pCO 2）对碳，氮，磷和硅在颗粒物（PM）和DOM之间分配的影响，在两个世界性的沿海硅藻，Chaetoceros affinis和Ditylum brightwellii，在营养盐充足和硝酸盐耗尽的条件下。在养分充足的条件下，两种物种的特定生长率与pCO 2水平呈正相关。指数增长的硅藻的元素组成是稳定的不同pCO 2条件下。硝酸盐耗竭后，颗粒有机碳颗粒氮比和生物硅含量每单位生物量在这两个物种与pCO 2值呈正相关。影响元素组成pCO 2依赖性变化的因素是有机碳在C. affinis，胞内碳、氮、硅、氮的生理解偶联，以及休眠孢子的形成。布莱特威利。在高CO2条件下，这两种硅藻的快速生长速率可能导致它们在浮游植物群落中占主导地位;它们的水华可能会改变硝酸盐耗竭后生物元素地球化学循环的一级过程。
Although the dissolved inorganic carbon concentration, pH, and nutrient regimes of seawater dramatically change in coastal regions, the synergistic effects of changes in the CO2 and nutrient levels on the elemental dynamics of the particulate and dissolved organic matters (DOMs) produced by diatoms are rarely investigated. Here, we investigated the impacts of four different CO2 levels (180, 380, 600, and 1000 μatm partial pressure of CO2 : pCO2) on the allocation of carbon, nitrogen, phosphorus, and silicon between the particulate matter (PM) and DOM in two cosmopolitan coastal diatoms, Chaetoceros affinis and Ditylum brightwellii, under nutrient‐replete and nitrate‐depleted conditions. Under nutrient‐replete conditions, the specific growth rates of both species were positively correlated with pCO2 levels. The elemental compositions of the exponentially growing diatoms were stable under the different pCO2 conditions. After nitrate depletion, the particulate organic carbon to particulate nitrogen ratio and biogenic silica content per unit biomass in both species were positively correlated with the pCO2 value. Factors affecting the pCO2 dependent change in elemental composition were the variations in the partitioning of organic carbon between PM and DOM in C. affinis, and the physiological uncoupling of intracellular carbon and nitrogen and the intracellular silicon and nitrogen, as well as resting spore formation in D. brightwellii. Under high‐CO2 conditions, the faster growth rates of both diatom species could lead to their dominance in a phytoplankton community; their blooms could modify the first‐order processes in the biogeochemical cycling of bioelements after nitrate depletion.