南极普里兹湾海域夏季表层水体颗粒有机碳及其同位素分布特征

DISTRIBUTION OF PARTICULATE ORGANIC CARBON(POC) AND δ^(13)C_(POC) IN SURFACE WATERS IN SUMMER IN PRYDZ BAY,ANTARCTICA

基于中国第29次南极科学考察在普里兹湾海域采集的61个站位的表层悬浮体样品的颗粒有机碳(POC)及其稳定同位素(δ13CPOC)测试结果,结合卫星遥感解译的研究区海水表面温度(SST)、叶绿素a(Chl a)浓度和海冰覆盖率数据,研究了普里兹湾海域表层水体悬浮POC的分布特征,探讨了悬浮体中POC的来源及其形成过程。结果表明,2013年夏季普里兹湾表层悬浮POC浓度为0.28—0.84 mg·L-1,平均浓度为0.48 mg·L-1;δ13CPOC值的变化范围为-29.68‰—-26.30‰,平均值为-28.01‰。表层水体悬浮POC分布呈现近岸高于远岸,西部高于东部的特征。POC的高值区主要分布在冰架附近,与表层水体Chl a浓度和海冰覆盖率分布趋势基本一致,表明夏季普里兹湾表层水体悬浮POC主要由浮游植物现场生产,而浮游植物的生长受到了海冰的显著影响。在普里兹湾外部海域表层水体悬浮颗粒物δ13CPOC值从东向西逐渐偏负,而调查区东部从近岸向远海逐渐偏负,反映该海域δ13CPOC分布特征主要受到浮游植物吸收与固定CO2速率的影响。中山站附近海域δ13CPOC值显著偏负,可能是受到近岸海域陆源有机质输入和浮游生物种属改变的影响。

The 29th Chinese National Antarctic Research Expedition collected 61 samples of surface suspensions of particulate organic carbon （POC） in Prydz Bay, Antarctica. The factors influencing the distribution of POC, and its sources and transport processes, were studied by analyzing the distribution of the POC and δ13 Cpoc values and the surface sea temperatures, chlorophyll a concentrations and sea ice coverage measured by satellite remote sensing. The results showed that POC concentration in the surface layer of Prydz Bay was 0. 28--0.84 mg . L- 1, with an average of 0.48 mg . L-1. δ13 Cpoc values varied from -29. 68‰ to -26. 30‰, with an average value of -28.01‰. The surface POC distribution in summer shows that high values of POC are mainly found near ice shelves, and POC values in the western survey area are higher than those in the eastern region. The POC content shows a good correlation with chlorophyll a concentration and sea ice coverage, suggesting that POC was mainly derived from phytoplankton production in the local water column, while the growth of phytoplankton was obviously affected by sea ice. The δ13Cpoc values gradually decrease from east to west outside of Prydz Bay, whereas from the shore to the sea the δ3Cpoc values gradually beeome more negative in the eastern survey area, suggesting that δ13 C poc was mainly influenced by the rate of phytoplankton CO2 fixation outside Prydz Bay waters. The δ3 C poc value in coastal waters near Zhongshan Station was significantly more negative. Terrigenous organic detritus inputs and changes in phytoplankton species might have contributed to the carbon isotopic values of POC.