Alkalinity changes in the Sargasso Sea: geochemical evidence of calcification?
Alkalinity changes in the Sargasso Sea: geochemical evidence of calcification?
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DOI：
10.1016/0304-4203(95)00068-2
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发表时间：
1996
期刊：
影响因子：
3
通讯作者：
N. Bates;Anthony F. Michaels;A. Knap
中科院分区：
文献类型：
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作者：
N. Bates;Anthony F. Michaels;A. Knap
在美国全球海洋通量联合研究（JGOFS）BATS站点（31 °50′N，64 °10′W）的马尾藻海收集的水柱测量数据中，观测到上层海洋总二氧化碳（TCO 2）、碱度（TA）和计算的pCO 2的强烈季节性模式。TA分布是盐度的保守函数。然而，在1992年2月，观测到TA的非保守减少，最大消耗量为25-30 μ mol kg− 1，发生在表层和叶绿素最大值的深度（约80-100 m）。混合层TCO 2也降低，而表面pCO 2增加了25-30 μatm。我们认为，这些二氧化碳物种的变化是由碳酸盐分泌生物的开放海洋钙化而不是物理过程造成的。尽管不能排除有孔虫或翼足类动物的钙化，但颗石藻钙化是该事件最可能的原因。由于表面pCO 2的瞬时增加，在BATS向海洋的CO2净年转移减少。这些观测结果表明，公海钙化和生物群落结构在碳的地球化学循环中具有潜在的重要性。
Strong seasonal patterns in upper ocean total carbon dioxide (TCO2), alkalinity (TA) and calculated pCO2were observed in a time series of water column measurements collected at the US Joint Global Ocean Flux Study (JGOFS) BATS site (31 °50′N, 64 °10′W) in the Sargasso Sea. TA distribution was a conservative function of salinity. However, in February 1992, a non-conservative decrease in TA was observed, with maximum depletion of 25–30 μmoles kg−1occuring in the surface layer and at the depth of the chlorophyll maximum (~ 80–100 m). Mixed-layer TCO2also decreased, while surface pCO2increased by 25–30 μatm. We suggest these changes in carbon dioxide species resulted from open-ocean calcification by carbonate-secreting organisms rather than physical processes. Coccolithophore calcification is the most likely cause of this event although calcification by foraminifera or pteropods cannot be ruled out. Due to the transient increase in surface pCO2, the net annual transfer of CO2into the ocean at BATS was reduced. These observations demonstrate the potential importance of open-ocean calcification and biological community structure in the biogeochemical cycling of carbon.