The Antarctic Ice Edge Bloom: Its Importance to Intermediate Trophic Levels

南极冰缘作为一个锋面系统，对于不同的营养水平有着不同的含义。在夏季，初级生产者和微型异养生物在融水透镜中蓬勃发展，这些透镜是在退缩的冰缘的真光带中产生的。相比之下，对于世代时间为一年或更长时间的寿命较长的消费物种来说，冰缘上任何增强的站立种群都必须是迁徙到冰缘或就地生产的结果。这项研究将检验这样一种假设，即夏季冰缘水华作为生物磁铁，集中后生动物消费者，并作为向南移动的发电机，促进浮游动物物种的生长和繁殖。南半球夏季在斯科舍-韦德尔海地区进行的研究将集中在研究区开阔水域、边缘冰带和浮冰堆积区水柱以上1000米处浮游动物和微型浮游动物的分布、丰度和生物活性。将描述物理环境；将使用活体荧光绘制冰缘浮游植物水华的范围和活动图，并将对初级生产力进行估计。将利用光学浮游生物采样器以及渔网和拖网的数据来描述浮游动物/微型浮游动物群落结构。浮游动物的生物活性将通过代谢率、放牧率、产蛋率、饲料和代谢酶活性的研究来评估。由此产生的数据将描述浮游动物/微型浮游动物群落结构、主要营养关系、放牧影响以及生活在研究区域的物种的能量利用模式，清楚地显示冰缘水华对中等营养水平的影响。

The Antarctic ice edge as a frontal system has different implications for different trophic levels. During summer, primary producers and microheterotrophs flourish in the meltwater lens that is created in the euphotic zone at the retreating ice edge. In contrast, for longer-lived consumer species with generation times of a year or more, any enhanced standing stocks at the ice edge must be the result of immigration to the ice edge or production in place. This research will test the hypothesis that the summer ice edge bloom acts as a biological magnet to concentrate metazoan consumers and as a southward moving generator facilitating growth and reproduction in zooplankton species. Research conducted in the Scotia-Weddell Sea region during the austral summer will focus on the distribution, abundance, and biological activity of zooplankton and micronekton in the upper 1000m of the water column in the open water, marginal ice zone, and pack ice regions of the study area. The physical environment will be described; the extent and activity of the ice edge phytoplankton bloom will be mapped using in vivo fluourescence and estimates of primary production will be made. Zooplankton/micronekton community structure will be characterized using data from an optical plankton sampler, as well as nets and trawls. Biological activity of zooplankton will be evaluated through studies of metabolic rate, grazing rate, egg production rate, diet, and metabolic enzyme activity. The resultant data will describe zooplankton/micronekton community structure, major trophic relationships, grazing impact, and patterns of energy utilization for species living in the study area, showing clearly the impact of the ice edge bloom on the intermediate trophic levels.