Climate forcing for dynamics of dissolved inorganic nutrients at Palmer Station, Antarctica: An interdecadal (1993-2013) analysis
Climate forcing for dynamics of dissolved inorganic nutrients at Palmer Station, Antarctica: An interdecadal (1993-2013) analysis
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DOI：
10.1002/2015jg003311
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发表时间：
2016-09-01
影响因子：
3.7
通讯作者：
Ducklow, Hugh W.
中科院分区：
文献类型：
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作者：
Kim, Hyewon;Doney, Scott C.;Ducklow, Hugh W.
我们分析了 20 年（1993-2013 年）在南极洲帕尔默站（南纬 64.8 度，西经 64.1 度）溶解的无机大量营养素（硝酸盐，N；磷酸盐，P；和硅酸盐，Si）和叶绿素 a (Chl) 的观测结果，以阐明大规模气候和当地物理强迫如何影响季节性浮游植物水华的年际变化以及相关的营养物质减少。营养物质的主要模式（N、P 和 Si 经验正交函数 1，EOF1）代表整个生长季节的总体负异常，显示初始水平和此后下降的可变性混合信号（低频动态）。硝酸盐和磷酸盐（N 和 P EOF2）的第二常见季节性模式捕获 12 月至 3 月期间的长期下降事件，这与 Chl EOF1 相关。 Si EOF2 捕获 11 月至 12 月期间的回撤事件，这与 Chl EOF2 相关。这些不同的下降模式是由不同的物理和气候强迫机制形成的。 12 月至 3 月期间的氮和磷下降事件受到冬季和春季南环模 (SAM) 阶段的影响，由于 SAM 驱动的冬季海冰和春季风动力学，稳定的上层水柱中的养分利用率得到增强。 11 月至 12 月期间的 Si 下降受到海冰早期退缩的影响，其中冰破裂可能导致水柱突然分层以及随后的硅藻华或硅藻细胞从海冰内释放。我们的研究结果强调，沿海 WAP 的季节性营养动态与大规模气候强迫和相关物理现象相耦合，了解其可能有助于改进生物地球化学对气候变化响应的预测。
We analyzed 20years (1993-2013) of observations of dissolved inorganic macronutrients (nitrate, N; phosphate, P; and silicate, Si) and chlorophyll a (Chl) at Palmer Station, Antarctica (64.8 degrees S, 64.1 degrees W) to elucidate how large-scale climate and local physical forcing affect the interannual variability in the seasonal phytoplankton bloom and associated drawdown of nutrients. The leading modes of nutrients (N, P, and Si empirical orthogonal functions 1, EOF1) represent overall negative anomalies throughout growing seasons, showing a mixed signal of variability in the initial levels and drawdown thereafter (low-frequency dynamics). The second most common seasonal patterns of nitrate and phosphate (N and P EOF2) capture prolonged drawdown events during December-March, which are correlated to Chl EOF1. Si EOF2 captures a drawdown event during November-December, which is correlated to Chl EOF2. These different drawdown patterns are shaped by different sets of physical and climate forcing mechanisms. N and P drawdown events during December-March are influenced by the winter and spring Southern Annular Mode (SAM) phase, where nutrient utilization is enhanced in a stabilized upper water column as a consequence of SAM-driven winter sea ice and spring wind dynamics. Si drawdown during November-December is influenced by early sea ice retreat, where ice breakup may induce abrupt water column stratification and a subsequent diatom bloom or release of diatom cells from within the sea ice. Our findings underscore that seasonal nutrient dynamics in the coastal WAP are coupled to large-scale climate forcing and related physics, understanding of which may enable improved projections of biogeochemical responses to climate change.