Linking Southern Ocean Mixed‐Layer Dynamics to Net Community Production on Various Timescales
Linking Southern Ocean Mixed‐Layer Dynamics to Net Community Production on Various Timescales
复制标题
将南大洋混合层动态与不同时间尺度的网络群落生产联系起来
DOI：
10.1029/2021jc017537
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Cassar, Nicolas
中科院分区：
文献类型：
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作者：
Li, Zuchuan;Lozier, M. Susan;Cassar, Nicolas
混合层动力学对浮游植物的营养和光利用率进行一级控制。在这项研究中，我们利用1997年至2020年期间生物地球化学Argo浮标和卫星NCP估计值，研究了混合层动态对南大洋净群落生产（NCP）在季节内、季节、年际和年代际时间尺度上的影响。在季节内时间尺度上，混合层的浅滩更有可能增强南大洋春季和冬季的NCP，这表明南大洋的净群落生产（NCP）的减弱光的限制。正如预期的那样，NCP 通常会随着季节性时间尺度上的光照可用性而增加。在年际时间尺度上，NCP与南方春季和冬季的混合层深度（MLD）和混合层平均光合有效辐射（PAR）相关，特别是在混合层较深的地区。尽管最近的研究认为冬季 MLD 控制了随后生长季的铁和光可用性，但与我们的卫星观测同时进行的有限数量的 Argo 浮标观测并未显示出 NCP 与前一个冬季的 MLD 在年际时间尺度上存在显着相关性。在 1997 年至 2020 年期间，我们观察到 NCP 的区域趋势（例如，南美洲周围增加），但整个南大洋没有趋势。总的来说，我们的结果表明 NCP 对 MLD 的依赖性是时间尺度的复杂函数。
Mixed‐layer dynamics exert a first order control on nutrient and light availability for phytoplankton. In this study, we examine the influence of mixed‐layer dynamics on net community production (NCP) in the Southern Ocean on intra‐seasonal, seasonal, interannual, and decadal timescales, using biogeochemical Argo floats and satellite‐derived NCP estimates during the period from 1997 to 2020. On intraseasonal timescales, the shoaling of the mixed layer is more likely to enhance NCP in austral spring and winter, suggesting an alleviation of light limitation. As expected, NCP generally increases with light availability on seasonal timescales. On interannual timescales, NCP is correlated with mixed layer depth (MLD) and mixed‐layer‐averaged photosynthetically active radiation (PAR) in austral spring and winter, especially in regions with deeper mixed layers. Though recent studies have argued that winter MLD controls the subsequent growing season's iron and light availability, the limited number of Argo float observations contemporaneous with our satellite observations do not show a significant correlation between NCP and the previous‐winter's MLD on interannual timescales. Over the 1997–2020 period, we observe regional trends in NCP (e.g., increasing around S. America), but no trend for the entire Southern Ocean. Overall, our results show that the dependence of NCP on MLD is a complex function of timescales.