Phytoplankton production after the collapse of the Larsen A Ice Shelf, Antarctica
Phytoplankton production after the collapse of the Larsen A Ice Shelf, Antarctica
复制标题
南极洲拉森 A 冰架崩塌后浮游植物的产生
作者：
M. Bertolin;I. Schloss
拉森A冰架的一部分(°15‘S至74°15’S)于1995年1月坍塌。1996年12月，从新的自由水域获得了第一组海洋学和生物数据。发现了典型的陆架水域，温度在冰点附近和以下。在70~200m水深范围内，发现了一个营养丰富的水团(最大值：PO43−1.80μmol.L−1和NO3−27.64μmol.L−1)。叶绿素a(Chl-a)值较高(最大为14.24gμg/L−1)，表面氧饱和度在86%~148%之间。尼氏藻属和舟形藻属的硅藻以及裸子植物棕囊藻。是所发现的最丰富的类群。根据营养物质消耗估算的平均日第一性生产量(Pc)为14.80±0.17mgC/m−3 d−1。Pc与硅藻总丰度和Chl-a显著相关。计算的Δ二氧化碳(表层海水和大气之间的二氧化碳分压之差)为-30.5tμatm，这可能是从大气到海洋的二氧化碳净通量的贡献，表明该地区在研究期间一直是二氧化碳汇。在这个新开阔的区域发现了较高的浮游植物生物量和生产值，这表明它对生物二氧化碳排放具有重要意义。
Part of the Larsen A Ice Shelf (64°15′S to 74°15′S) collapsed during January 1995. A first oceanographic and biological data set from the newly free waters was obtained during December 1996. Typical shelf waters with temperatures near and below the freezing point were found. A nutrient-rich water mass (max: PO43− 1.80 μmol L−1 and NO3− 27.64 μmol L−1) was found between 70 and 200 m depth. Chlorophyll-a (Chl-a) values (max 14.24 μg L−1) were high; surface oxygen saturation ranged between 86 and 148%. Diatoms of the genera Nitzschia and Navicula and the prymnesiophyte Phaeocystis sp. were the most abundant taxa found. Mean daily primary production (Pc) estimated from nutrient consumption was 14.80 ± 0.17 mgC m−3 day−1. Pc was significantly correlated with total diatom abundance and Chl-a. Calculated ΔpCO2 (difference of the CO2 partial pressure between surface seawater and the atmosphere) was –30.5 μatm, which could have contributed to a net CO2 flux from the atmosphere to the sea and suggests the area has been a CO2 sink during the studied period. High phytoplankton biomass and production values were found in this freshly open area, suggesting its importance for biological CO2 pumping.