Seasonal and interannual variability in temperature, chlorophyll and macronutrients in northern Marguerite Bay, Antarctica
Seasonal and interannual variability in temperature, chlorophyll and macronutrients in northern Marguerite Bay, Antarctica
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DOI：
10.1016/j.dsr2.2008.04.035
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发表时间：
2008-09-01
影响因子：
3
通讯作者：
Thomas, David N.
中科院分区：
文献类型：
--
作者：
Clarke, Andrew;Meredith, Michael P.;Thomas, David N.
我们报道了南极洲玛格丽特湾北部莱德湾前8年的海洋监测数据。这些数据构成了Rothera海洋和生物时间序列(RATS)项目的海洋学组成部分。在天气和冰条件允许的情况下，夏季每隔5天就有一次老鼠站被占用，冬季每周一次。观测包括电导率-温度-深度(CTD)到500米和15米的水样，这是大多数年份叶绿素最大值的深度。水样提供了总叶绿素(20、5、2和0.2微米)、常量营养素(N、P和Si)和溶解有机碳(DOC)的数据。CTD剖面显示，南极表层水(AASW)具有很强的季节性，夏季的太阳加热和冬季的冷却以及结冰过程中的卤水排除是驱动AASW的原因。冬季混合层的深度在8月份达到最大值，年最大值在30~140m之间。AASW以下是相对季节性的冬季水(WW)，剖面的底部指示存在修正的上绕极深水(UCDW)。夏季叶绿素一般超过20mgm(-3)，1月份达到峰值。植物碎屑的垂直通量也主要出现在1月份。夏季水华以大型硅藻和聚集态为主，冬季大部分叶绿素以超微浮游植物(20-5亩)形式存在。常量营养元素具有明显的季节性，N：P协变接近Redfield(类似于15.3)，Si：N化学计量比接近1.67。夏季DOC值表现出较少的季节性，冬季水平相对较高(>；50亩M)。表层水也表现出明显的年际变化，ENSO是次十年尺度上的一个重要驱动因素。(C)2008爱思唯尔有限公司。保留所有权利。
We report data from the first 8 years of oceanographic monitoring in Ryder Bay, northern Marguerite Bay, Antarctica. These data form the oceanographic component of the Rothera Oceanographic and Biological Time-Series (RaTS) project. When weather and ice permit, the RaTS station is occupied every 5 days in summer and weekly in winter. Observations comprise a conductivity-temperature-depth (CTD) cast to 500 m and a water sample from 15 m, this being the depth of the chlorophyll maximum in most years. The water samples provide data on total chlorophyll (size-fractionated at 20, 5, 2 and 0.2 mu m), macronutrients (N, P and Si) and dissolved organic carbon (DOC). The CTD profiles reveal strong seasonality in the topmost Antarctic Surface Water (AASW) driven by summer solar heating and winter cooling with brine rejection during ice formation. The depth of the winter mixed layer reaches a maximum in August, with annual maximum values ranging from similar to 30 to > 140 m. Below the AASW is the relatively a seasonal Winter Water (WW), and the bottom of the profile indicates the presence of modified Upper Circumpolar Deep Water (UCDW). Summer chlorophyll typically exceeds 20 mg m(-3), with the peak in January. Vertical flux of phytodetritus is also predominantly in January. The summer bloom is dominated by large diatoms and colonial forms, whereas in winter most of the chlorophyll is in the nanophytoplankton (20-5 mu m) fraction. Macronutrients show marked seasonality with N:P covariation close to Redfield (similar to 15.3) and Si:N stoichiometry similar to 1.67. Summer DOC values show little seasonality and relatively high winter levels (>50 mu M). Surface waters also exhibit a marked interannual variability, with ENSO as an important driver at subdecadal scales. (C) 2008 Elsevier Ltd. All rights reserved.