Responses of the large centric diatom Coscinodiscus sp. to interactions between warming, elevated CO 2 , and nitrate availability: Diatom responses to climate changes
Responses of the large centric diatom Coscinodiscus sp. to interactions between warming, elevated CO 2 , and nitrate availability: Diatom responses to climate changes
复制标题
大中心硅藻 Coscinodiscus sp 的响应。
DOI：
10.1002/lno.10781
复制
发表时间：
2018
影响因子：
4.5
通讯作者：
Hutchins, David A.
中科院分区：
文献类型：
--
作者：
Qu, Pingping;Fu, Feixue;Hutchins, David A.
海洋生态系统正面临多种人为全球变化，包括海洋酸化、变暖和营养供应减少。总之，这些将挑战浮游植物，包括大型中心硅藻，如圆筛藻，这是一个对海洋食物网和碳输出很重要的群体。我们在一个四处理析因实验中研究了变暖、CO2升高和硝酸盐可用性对Coscinocdiscus生长、元素化学计量以及Fe和C吸收速率的交互作用，该实验结合了两个CO2水平（10400 ppm和800 ppm）和两个温度（16°C和20°C）以及七种硝酸盐浓度（1-100μmol L−1）。较高的温度导致较高的最大生长速率（μmax），但硝酸盐的半饱和常数（K1/2）也较高，而CO2升高仅在较高的温度下增加K1/2。在气候变暖和CO2浓度升高的条件下，μmax/K1/2比值较低，表明在这些条件下，硝酸盐需要量较高。高温降低了细胞的P和Si含量，从而增加了N：P和C：Si比，特别是在环境CO2。铁：碳吸收比积极响应较低的硝酸盐水平，较低的CO2，和变暖。在比生长速率、叶绿素a和Si含量、Fe：C、N：P和Si：C中，NO3--N和CO2的交互作用显著，而温度和CO2的交互作用仅对μmax/K1/2和细胞P含量显著。CO2浓度、温度和硝酸盐供应之间的相互作用都可能影响Coscinodiscussp.未来的生长、生理和碳输出，然而，一般来说，变暖和硝酸盐供应似乎比CO2更有影响力。
Marine ecosystems are facing multiple anthropogenic global changes, including ocean acidification, warming, and reduced nutrient supplies. Together, these will challenge phytoplankton including large centric diatoms such asCoscinodiscussp., a group that is important to ocean food webs and carbon export. We investigated the interactive effects of warming, elevated CO2, and nitrate availability onCoscinodiscusgrowth, elemental stoichiometry, and Fe and C uptake rates in a four‐treatment factorial experiment combining two CO2levels (∼400 ppm and 800 ppm) and two temperatures (16°C and 20°C) across seven nitrate concentrations (1–100μmol L−1). Higher temperatures led to higher maximum growth rates (μmax), but also higher half‐saturation constants for nitrate (K1/2), while elevated CO2increasedK1/2only at the warmer temperature. Lowerμmax/K1/2ratios under warming and rising CO2indicated a higher nitrate requirement at these conditions. High temperature decreased cellular P and Si contents and consequently increased N : P and C : Si ratios, especially at ambient CO2. Fe : C uptake ratios responded positively to lower nitrate levels, lower CO2, and warming. Significant interactions between nitrate availability and temperature or CO2were observed for specific growth rates, chlorophyllaand Si contents, Fe : C, N : P, and Si : C, while temperature and CO2interactions were only significant forμmax/K1/2and cellular P content. The mutual interactions among CO2concentrations, temperature, and nitrate supply may all affect future growth, physiology, and carbon export byCoscinodiscussp., however, in general warming and nitrate availability appear to be more influential than CO2.