Global patterns of phytoplankton nutrient and light colimitation inferred from an optimality-based model
Global patterns of phytoplankton nutrient and light colimitation inferred from an optimality-based model
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DOI：
10.1002/2013gb004668
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发表时间：
2014-07-01
影响因子：
5.2
通讯作者：
Oschlies, Andreas
中科院分区：
文献类型：
--
作者：
Arteaga, Lionel;Pahlow, Markus;Oschlies, Andreas
广泛使用的恒定“雷德菲尔德”浮游植物化学计量概念通常用于估计哪些营养物质限制了海洋表层浮游植物的生长。相反，培养实验显示生长条件和细胞化学计量之间存在密切关系，并且通常与雷德菲尔德化学计量有很大偏差。在这里，我们通过分析遥感和现场数据以及基于最优性的非固氮浮游植物生长模型来研究两种观点的一致程度，以推断全球海洋中光、氮（N）和磷（P）共限的季节性变化模式。我们的综合模型数据分析表明，热带海洋存在强烈的 N 和 N-P 共限，北半球存在季节性光照和 N-P 共限，而南大洋仅在冬季存在强烈的光照限制。赤道东太平洋似乎是唯一基本上不受北纬或光限制的海洋区域。尽管我们基于最优性的方法专门考虑了灵活的化学计量，但 N 和 P 限制的推断模式在某种程度上与从 Redfield N:P 比率的表面无机养分分析中获得的模式一致。铁不是我们分析的一部分，这意味着我们无法准确预测高营养、低叶绿素区域的 N 细胞配额。在其他地方，我们预计铁不会对 N、P 和轻共限区域的相对分布产生重大影响。通过结合观测和最佳生长模型，本文诊断出氮、磷和光在限制浮游植物生长方面的相对重要性，为用于预测不断变化的环境条件下未来海洋生物生产的模型提供了有用的约束。
The widely used concept of constant "Redfield" phytoplankton stoichiometry is often applied for estimating which nutrient limits phytoplankton growth in the surface ocean. Culture experiments, in contrast, show strong relations between growth conditions and cellular stoichiometry with often substantial deviations from Redfield stoichiometry. Here we investigate to what extent both views agree by analyzing remote sensing and in situ data with an optimality-based model of nondiazotrophic phytoplankton growth in order to infer seasonally varying patterns of colimitation by light, nitrogen (N), and phosphorus (P) in the global ocean. Our combined model-data analysis suggests strong N and N-P colimitation in the tropical ocean, seasonal light, and N-P colimitation in the Northern Hemisphere, and strong light limitation only during winter in the Southern Ocean. The eastern equatorial Pacific appears as the only ocean area that is essentially not limited by N, P, or light. Even though our optimality-based approach specifically accounts for flexible stoichiometry, inferred patterns of N and P limitation are to some extent consistent with those obtained from an analysis of surface inorganic nutrients with respect to the Redfield N: P ratio. Iron is not part of our analysis, implying that we cannot accurately predict N cell quotas in high-nutrient, low-chlorophyll regions. Elsewhere, we do not expect a major effect of iron on the relative distribution of N, P, and light colimitation areas. The relative importance of N, P, and light in limiting phytoplankton growth diagnosed here by combining observations and an optimal growth model provides a useful constraint for models used to predict future marine biological production under changing environmental conditions.