Seasonal dynamics of the carbonate system in the Western English Channel
Seasonal dynamics of the carbonate system in the Western English Channel
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DOI：
10.1016/j.csr.2012.04.012
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发表时间：
2012-07-01
影响因子：
2.3
通讯作者：
Smyth, Timothy J.
中科院分区：
文献类型：
--
作者：
Kitidis, Vassilis;Hardman-Mountford, Nicholas J.;Smyth, Timothy J.
我们展示了四年（2007 年至 2010 年）在西英吉利海峡 (WEC) 收集的 900 多个碳酸盐系统观测结果。我们沿着一系列 40 公里的横断面测定了二氧化碳分压 (pCO(2))、总碱度 (TA) 和溶解无机碳 (DIC)，其中包括一个持续的沿海观测站内的两个海洋站（L4 和 E1）。我们的数据遵循一月至八月二氧化碳不饱和的季节性模式，随后是九月至十月的过饱和，此后恢复到接近平衡。这种模式可以通过冬季和春夏季热汇和生物汇的相互作用来解释，随后是秋季分层的瓦解并与更深的高二氧化碳水混合。 3月至6月期间DIC和无机氮的下降，C:N比为8.7-9.5，这与浮游植物生长期间碳的过度消耗一致。月平均表面 pCO(2) 与深度积分叶绿素 a 密切相关，突显了地下叶绿素 a 最大值在控制陆架海碳通量方面的重要性。近岸样品中海水与河流淡水的混合导致 TA 和方解石矿物饱和状态的减少，特别是在冬季。我们的数据显示，L4 和 El 海洋站在年度循环中的大气二氧化碳净汇量较小（分别为 -0.52 +/- 0.66 mol C m(-2) y(-1) -0.62 +/- 0.49 mol C m(-2) y(-1)）。 (C) 2012 Elsevier Ltd. 保留所有权利。
We present over 900 carbonate system observations collected over four years (2007-2010) in the Western English Channel (WEC). We determined CO2 partial pressure (pCO(2)), Total Alkalinity (TA) and Dissolved Inorganic Carbon (DIC) along a series of 40 km transects, including two oceanographic stations (L4 and E1) within a sustained coastal observatory. Our data follow a seasonal pattern of CO2 undersaturation from January to August, followed by supersaturation in September-October and a return to near-equilibrium thereafter. This pattern is explained by the interplay of thermal and biological sinks in winter and spring-summer, respectively, followed by the breakdown of stratification and mixing with deeper, high-CO2 water in autumn. The drawdown of DIC and inorganic N between March and June with a C:N ratio of 8.7-9.5 was consistent with carbon over-consumption during phytoplankton growth. Monthly mean surface pCO(2) was strongly correlated with depth integrated chlorophyll a highlighting the importance of subsurface chlorophyll a maxima in controlling C-fluxes in shelf seas. Mixing of seawater with riverine freshwater in near-shore samples caused a reduction in TA and the saturation state of calcite minerals, particularly in winter. Our data show that the L4 and El oceanographic stations were small, net sinks for atmospheric CO2 over an annual cycle (-0.52 +/- 0.66 mol C m(-2) y(-1) -0.62 +/- 0.49 mol C m(-2) y(-1), respectively). (C) 2012 Elsevier Ltd. All rights reserved.