Spatial and temporal variability in phytoplankton carbon, chlorophyll, and nitrogen in the North Pacific
Spatial and temporal variability in phytoplankton carbon, chlorophyll, and nitrogen in the North Pacific
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DOI：
10.1029/2012jc008067
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发表时间：
2012-11
影响因子：
--
通讯作者：
P. Xiu;F. Chai
中科院分区：
文献类型：
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作者：
P. Xiu;F. Chai
[1]碳、氮和叶绿素是量化浮游植物生产力的三个常用变量。然而，由于光、温度和养分的复杂影响，这三个变量通常是相互解耦的。通过在太平洋盆地尺度环流模式中分别处理浮游植物碳、氮和叶绿素的生物地球化学模型，我们研究了不同尺度上浮游植物C：Chl和C：N比的物理和生物地球化学控制。该模型再现了太平洋海盆浮游植物动态的一般特征。模式结果表明，C/Chl比的驱动机制具有区域依赖性，其中C：Chl主要受高纬度的光照条件、中纬度的光和营养水平以及赤道太平洋的营养物质和温度控制，而C：N比似乎与区域无关，主要由营养物质和温度决定。太平洋盆地尺度的经验正交函数(EOF)分解表明，C：CHL和C：N都受厄尔尼诺/南方涛动(ENSO)事件的一阶变率调节。由于C：Chl的变化，浮游植物碳和叶绿素之间存在解耦，特别是在季节和长期时间尺度上。气候变化会影响浮游植物的色素、生物量和生理状态。因此，用叶绿素作为浮游植物生物量的替代物来解释十年变化或长期趋势可能是有偏差的。
[1] Carbon, nitrogen, and chlorophyll are three commonly used variables to quantify phytoplankton productivity. However, owing to the complex effect of light, temperature, and nutrient, these three variables are usually decoupled from each other. By implementing a biogeochemical model that treats phytoplankton carbon, nitrogen, and chlorophyll separately in a Pacific basin-scale circulation model, we have investigated the physical and biogeochemical controls on phytoplankton C:Chl and C:N ratios at different scales. The model reproduces the general features of phytoplankton dynamics in the Pacific basin. Model results indicate a region dependent pattern of driving mechanisms for C:Chl ratio, where C:Chl is largely controlled by light condition in high latitude, by light and nutrient levels in midlatitude, and by nutrient and temperature in the equatorial Pacific, while C:N ratio seems to be region independent and is mostly determined by nutrient and temperature. Pacific basin-scale empirical orthogonal functions (EOF) decompositions suggest both C:Chl and C:N are regulated by the El Nino/Southern Oscillation (ENSO) events to the first-order variability. Owing to the variation of C:Chl, the decoupling between phytoplankton carbon and chlorophyll exists, especially at seasonal and long-term temporal scales. Climate change can affect phytoplankton pigment, biomass, and physiological state. As a consequence, using chlorophyll as a proxy for phytoplankton biomass to interpret decadal variation or long-term trend might be with bias.