Ecological controls on biogeochemical fluxes in the western Antarctic Peninsula studied with an inverse foodweb model
Ecological controls on biogeochemical fluxes in the western Antarctic Peninsula studied with an inverse foodweb model
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DOI：
10.13679/j.advps.2015.2.00122
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发表时间：
2015-06-01
影响因子：
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通讯作者：
Sailley, S. F.
中科院分区：
文献类型：
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作者：
Ducklow, Hugh W.;Doney, S. C.;Sailley, S. F.
南极半岛西部海冰高度多变，变化迅速。在帕尔默站地区，自1978年以来，冰季持续时间减少了92d。海冰的变化影响海洋分层和淡水平衡，进而影响极地海洋生态系统的每个组成部分。来自WAP近岸和近海地区的长期观测显示了一种叶绿素(Chl)变化的模式，三到五年的Chl负异常被一到两年的正异常(高和低Chl区域)中断。野外观测和反向食物网模型的结果都表明，这些高和低Chl的状况彼此之间存在显著差异，高的初级生产力和净群落生产力(NCP)以及与高Chl年和低Chl年的低速率相关的其他速率。初级生产总值(GPP)平均为30mmolC。M(-2)。D(-1)在低Chl年和100mmolC。M(-2)。D(-1)在高叶绿年。大型和小型浮游植物在高Chl年都比低Chl年更丰富和更具生产力。类似地，磷虾在高Chl年作为食草动物更重要，但在高Chl年和低Chl年与微型浮游动物没有区别。小型浮游动物在Chl高年和低年之间没有差别。群落净生产量在高、低Chl年间差异显著，但在高、低Chl年间GPP的动员比例相近。NCP的组成在高、低Chl年间是一致的。这些结果强调了WAP浮游生物系统中微生物成分的重要性，并表明由小型浮游植物主导的食物网可能具有将生产输送到NCP并可能出口的途径。
Sea ice in the western Antarctic Peninsula (WAP) region is both highly variable and rapidly changing. In the Palmer Station region, the ice season duration has decreased by 92 d since 1978. The sea-ice changes affect ocean stratification and freshwater balance and in turn impact every component of the polar marine ecosystem. Long-term observations from the WAP nearshore and offshore regions show a pattern of chlorophyll (Chl) variability with three to five years of negative Chl anomalies interrupted by one or two years of positive anomalies (high and low Chl regimes). Both field observations and results from an inverse food-web model show that these high and low Chl regimes differed significantly from each other, with high primary productivity and net community production (NCP) and other rates associated with the high Chl years and low rates with low Chl years. Gross primary production rates (GPP) averaged 30 mmolC. m(-2). d(-1) in the low Chl years and 100 mmolC. m(-2). d(-1) in the high Chl years. Both large and small phytoplankton were more abundant and more productive in high Chl years than in low Chl years. Similarly, krill were more important as grazers in high Chl years, but did not differ from microzooplankton in high or low Chl years. Microzooplankton did not differ between high and low Chl years. Net community production differed significantly between high and low Chl years, but mobilized a similar proportion of GPP in both high and low Chl years. The composition of the NCP was uniform in high and low Chl years. These results emphasize the importance of microbial components in the WAP plankton system and suggest that food webs dominated by small phytoplankton can have pathways that funnel production into NCP, and likely, export.