Physical and Biological Drivers of Biogeochemical Tracers Within the Seasonal Sea Ice Zone of the Southern Ocean From Profiling Floats
Physical and Biological Drivers of Biogeochemical Tracers Within the Seasonal Sea Ice Zone of the Southern Ocean From Profiling Floats
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南大洋季节性海冰区内生物地球化学示踪剂的物理和生物驱动因素来自剖面浮标
DOI：
10.1002/2017jc012846
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发表时间：
2017
影响因子：
--
通讯作者：
K. Johnson
中科院分区：
文献类型：
--
作者：
E. Briggs;T. Martz;L. Talley;M. Mazloff;K. Johnson
在这里，我们展示了 9 个配备 pH、O 2 、NO – 3 和其他生物地球化学传感器的剖面浮标的初步发现，这些浮标通过南大洋碳和气候观测与模拟 (SOCCOM) 项目于 2014 年和 2015 年部署在南大洋季节性冰区 (SIZ)。春季，所有九个浮游物都观察到大量浮游植物大量繁殖，这与海冰融化同时发生。我们认为，这种水华是由于海冰融化导致混合层深度变浅、垂直稳定性增加以及养分和光可用性增强的结果。在观测的第二年，当其中一个漂浮物离开 SIZ 时，没有出现春季开花现象，这一解释得到了支持。在海冰覆盖期间，观察到净异养条件。 O 2 的吸收率以及溶解的无机碳（源自 pH 值和估计的总碱度）和 NO – 3 的释放率让人想起生物呼吸，并且对于九个浮子来说几乎是雷德菲尔德式的。开发了一种简单的混合层物理模型，用于在罗斯海 SIZ 中的浮标的一年周期内分离 pH 和 O 2 信号的物理和生物成分。由此产生的年度净群落生产表明，一年中有冰覆盖期间的季节性呼吸几乎平衡了无冰期间通光层中高达 5 mol C m 2 2 的生产，导致这一浮子向深处输出的净碳接近于零。
Here we present initial findings from nine profiling floats equipped with pH, O 2 , NO – 3 , and other biogeochemical sensors that were deployed in the seasonal ice zone (SIZ) of the Southern Ocean in 2014 and 2015 through the Southern Ocean Carbon and Climate Observations and Modelling (SOCCOM) project. A large springtime phytoplankton bloom was observed that coincided with sea ice melt for all nine floats. We argue this bloom results from a shoaling of the mixed layer depth, increased vertical stability, and enhanced nutrient and light availability as the sea ice melts. This interpretation is supported by the absence of a springtime bloom when one of the floats left the SIZ in the second year of observations. During the sea ice covered period, net heterotrophic conditions were observed. The rate of uptake of O 2 and release of dissolved inorganic carbon (derived from pH and estimated total alkalinity) and NO – 3 is reminiscent of biological respiration and is nearly Redfieldian for the nine floats. A simple model of mixed layer physics was developed to separate the physical and biological components of the signal in pH and O 2 over one annual cycle for a float in the Ross Sea SIZ. The resulting annual net community production suggests that seasonal respiration during the ice covered period of the year nearly balances the production in the euphotic layer of up to 5 mol C m 2 2 during the ice free period leading to a net of near zero carbon exported to depth for this one float.