Mesozooplankton metabolism and feeding in the NW Iberian upwelling
Mesozooplankton metabolism and feeding in the NW Iberian upwelling
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DOI：
10.1016/j.ecss.2004.04.011
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发表时间：
2004-09
影响因子：
2.8
通讯作者：
J. A. Isla;S. Ceballos;R. Anadón
中科院分区：
文献类型：
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作者：
J. A. Isla;S. Ceballos;R. Anadón
1998年8月，在西班牙西北部海域进行的一次巡航中，对浮游动物大小分级生物量、摄食和代谢率进行了调查。根据在整个研究区域观察到的不同水文条件（近岸上升流事件和近海分层沃茨），将取样区分为沿海区和海洋区。浮游植物和中型浮游动物生物量在沿海上升流高于在近海区。尺寸结构分析表明，在公海中，小部分（200-500μm）的中型浮游动物在生物量和放牧活动方面比大部分（500-1000μm和>1000μm）更重要。桡足类摄食率与叶绿素a >5μm浓度的关系类似于Ⅱ型功能反应。饱和发生在沿海站，桡足类肠道内容物最高。放牧对浮游植物生物量和初级生产力的影响似乎高于离岸（分别为5.7%和12.9%）比涌上沃茨（5.2%和5.2%），尽管差异在统计学上并不显著。浮游植物的摄入量足以满足上升流区（102.1%的最低碳需求满足），但不是在近海（45.9%）的中型浮游动物的基础代谢。浮游动物的摄食活动和代谢测量结果表明，在沿海上升流区的食草性食物网和在分层的开放海洋沃茨的多食性食物网。浮游动物代谢终产物的释放量较高的海岸带，但浮游动物发挥了更重要的作用，作为营养再生的多栖食物网（30.3%和21.7%的氮和磷浮游植物的需求占铵和磷酸盐排泄，分别）比草食性的（3.8%的铵和2.6%的磷酸盐）。
Mesozooplankton size-fractionated biomass, feeding, and metabolic rates were investigated during a cruise conducted off NW Spain in August 1998. Based on different hydrographic conditions observed throughout the study area (upwelling events nearshore and stratified waters offshore), the sampling area was divided into coastal and oceanic zones. Both phytoplankton and mesozooplankton biomass were higher in the coastal upwelling than in the offshore zone. Size structure analysis shows that the small fraction (200–500μm) of mesozooplankton was more important than the larger fractions (500–1000μm and >1000μm) in the open ocean in terms of both biomass and grazing activity. The relationship between copepod ingestion rate and the concentration of chlorophyll a >5μm resembled a type II functional response. Saturation occurred at the coastal stations, where copepod gut contents were highest. The grazing impact on both phytoplankton biomass and primary production seemed to be higher offshore (5.7 and 12.9%, respectively) than in upwelled waters (5.2 and 5.2%), although the differences were not statistically significant. Phytoplankton ingestion was enough to fulfil the basal metabolism of mesozooplankton in the upwelling area (102.1% of the minimum carbon requirements met) but not in the offshore (45.9%). Feeding activity and metabolic measurements on mesozooplankton point to a herbivorous food web in the coastal upwelling zone and a multivorous food web in the stratified open oceanic waters. The amount of metabolic end products released by mesozooplankton was higher in the coastal zone, but mesozooplankton played a more important role as nutrient regenerators in the multivorous food web (30.3 and 21.7% of the nitrogen and phosphorus phytoplankton demand accounted for ammonium and phosphate excretion, respectively) than in the herbivorous one (3.8% for ammonium and 2.6% for phosphate).