南极普里兹湾夏季冰间湖沉降通量

Sinking particle fluxes during austral summer in the Prydz Bay polynya, Antarctica

为研究南大洋的生物泵,利用2009~2010年和2014~2015年中国第26、31次中国南极科学考察期间于普里兹湾冰间湖布放的时间序列沉积物捕获器,获取了夏季沉降颗粒物通量并分析了其组成成分.结果表明:2009~2010年和2014~2015年南极夏季普里兹湾颗粒有机碳平均通量分别为4088.13,508.99μmol/(m^2·d),生物硅则分别为7358.91,2034.63μmol/(m^2·d),其中生物蛋白石占夏季颗粒物通量均超过70%,表明硅藻是普里兹湾夏季的优势种和沉降通量的主要贡献者.2014~2015年有机碳沉降通量仅为2009~2010年12.5%,主要是由于缺少压舱物无法使上层有机质发生快速沉降,造成异养微生物对上层水柱中有机质降解程度更高,进一步影响有机碳的沉降效率.与非硅藻优势种的海域相比,夏季普里兹湾具有非常高的沉降通量和沉降效率,利用Martin曲线估算夏季普里兹湾的100m深度沉降通量平均为净初级生产力的8.67%,主要归因于硅藻的高沉降效率.为了预测南极海域生物泵的变化,需要重点关注南大洋浮游植物群落结构的组成与变化.

To understand the biological pump of the Antarctic Ocean,two sets of time-series sediment trap was deployed and recovered in the polynya of the Prydz Bay during the 26^（th） and 31^（st） Chinese Antarctic scientific expeditions in the austral summer of 2009～2010 and 2014～2015.The particle fluxes were analyzed.The results showed that the summer fluxes of particulate organic carbon（POC）were 4088.13 and 508.99μmol/（m^2·d）for the year of 2009～2010and 2014～2015,respectively,while biogenic silica（BSi）were 7358.91 and 2034.63μmol/（m^2·d）,respectively.The biogenic opal contributed more than 70%of total mass flux in two years,which indicated diatoms should be the dominated species in the column and the main carriers of sinking POC during austral summer.The POC flux in2014～2015 was only 12.5%of that in 2009～2010.It was mainly due to the lack of ballast matters that prevented the rapid settling of organic matter in the upper layer,resulting in more degrading organic matter in the upper water column caused by heterotrophic microorganisms.Compared with other Antarctic marginal seas where the blooms were not dominated by diatoms,the Prydz Bay polynya is characterized of higher sinking fluxes and efficiency.Estimated by the Martin curve,the 100m POC flux in summer in Prydz Bay averages 8.67%of the net primary productivity.It mainly owed to the diatom-dominated plankton community in the Prydz Bay polynya,therefore the plankton community in polar oceans should attract more attention when predicting the variation of biological pump.