Study on the metabolism of two dominant copepods: Calanoides acutus and Metridia gerlachei collected in summer from the marginal ice zone of the Prydz Bay, Antarctica

Metabolic rates (oxygen consumption and ammonia excretion) of two dominant copepods, Calanoides acutus and Metridia gerlachei, were measured during the austral summer (December 1998 January 1999), in the marginal ice zone of the Prydz Bay. Their elemental compositions (C and N) were also analysed through these metabolic experiments. The results showed that C. acutus was 48.4% 48.6% of dry weight in carbon content and 6.1% 6.5% of dry weight in nitrogen content. Metridia gerlachei was 47.1% 50.1% and 5.9% 7.4%, relatively. Oxygen consumption rates of C. acutus were variant in the different areas (0.226 to 0.774 μlO 2mg -1h -1). And its ammonia excretion rates ranged from 0.014 to 0.105 μgNmg -1h -1. The ratio between the rates (O∶N) exhibited a large difference(5 6 times). For Metridia gerlachei, oxygen consumption rates were 0.488 0.644 μlO 2mg -1 and ammonia excretion rates were 0.015 0.034 μgNmg -1h -1. From the results of metabolic rate measurements and elemental analyses, daily losses of body carbon and nitrogen were estimated to be 0.59% 1.99% and 0.44% 3.27%, respectively. The metabolic carbon requirements accounted for 0 6% 29 2% of primary production per day, and their excretion of ammonia occupied 0.2% 38.0% of daily phytoplankton nitrogen demand.

南极普里兹湾夏季边缘浮冰区两种主要浮游桡足类的代谢研究

于 1 998年 1 2月至 1 999年 1月南极夏季 ,对南大洋普里兹湾临近海域两种主要浮游桡足类Calanoides acutus和 Metridia gerlachei的耗氧率和排氨率进行了现场调查 ,同时对其代谢产物对海洋初级生产的贡献进行了探讨。调查结果表明 ,C. acutus的体碳、氮含量占干重百分比分别为 48.4%～ 48.6%和 6.1 %～ 6.5% ;M.gerlachei分别为 47.1 %～ 50 .1 %和 5.9%～ 7.4%。C.acutus在不同海区耗氧率有一定的差异 (0 .2 2 6～ 0 .558μl O2 mg- 1h- 1)。排氨率变化范围为 0 .0 1 4～ 1 .0 58μg N mg- 1h- 1,最高值位于浮冰区 - 9站 ,在陆冰缘区 (FI站 )最小。不同海域其排氨率的高低与现场水温无相关性。不同站位上 C.acutus的 O:N比相差 5～ 6倍。M.gerlachei耗氧率为 0 .488～ 0 .644μl O2 mg- 1h- 1,排氨率为 0 .0 1 5～ 0 .0 34μg N mg- 1h- 1。根据代谢实验结果和桡足类自身碳氮含量推算 ,其维持正常代谢的碳、氮日损失率分别为 0 .59%～ 1 .99%和 0 .44%～ 3.2 7%。桡足类群体每天的碳需求量占初级生产力的 0 .6%～ 2 9.2 % ,氨氮日输出量占初级生产所需氮盐的 0 .2 %～ 38.0 %。