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首页> 外文期刊>ICES Journal of Marine Science >Carbon cycling through the pelagic foodweb in the northern Humboldt Current off Chile (23 °S)
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Carbon cycling through the pelagic foodweb in the northern Humboldt Current off Chile (23 °S)

机译：智利北部洪堡海流中的上层食物网中的碳循环（23°S）

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The structure of the zooplankton foodweb and their dominant carbon fluxes were studied in the upwelling system off northern Chile (Mejillones Bay; 23 °S) between October 2000 and December 2002. High primary production (PP) rates (1-8 gC m~(-2) d~(-1)) were mostly due to the net-phytoplankton size fraction (> 23 μm). High PP has been traditionally associated with the wind-driven upwelling fertilizing effect of equatorial subsurface waters, which favour development of a short food chain dominated by a few small clupeiform fish species. The objective of the present work was to study the trophic carbon flow through the first step of this "classical chain" (from phytoplankton to primary consumers such as copepods and euphausiids) and the carbon flow towards the gelatinous web composed of both filter-feeding and carnivorous zooplankton. To accomplish this objective, feeding experiments with copepods, appendicularians, ctenophores, and chaetognaths were conducted using naturally occurring plankton prey assemblages. Throughout the study, the total carbon ingestion rates showed that the dominant appendicularian species and small copepods consumed an average of 7 and 5 μgC ind~(-1) d~(-1), respectively. In addition, copepods ingested particles mainly in the size range of nano- and microplankton, whereas appendicularians ingested in the range of pico- and nanoplankton. Small copepods and appendicularians removed a small fraction of total daily PP (range 6 - 11%). However, when the pico- + nanoplankton fractions were the major contributors to total PP (oligotrophic conditions), grazing by small copepods increased markedly to 86% of total PP. Under these more oligotrophic conditions, the euphausiids grazing increased as well, but only reached values lower than 5% of total PP. During this study, chaetognaths and ctenophores ingested an average of 1 and 14 copepods ind~(-1) d~(-1), respectively. In terms of biomass consumed, the potential impact of carnivorous gelatinous zooplankton on the small-size copepod community (preferred prey) was important (2 - 12% of biomass removed daily). However, their impact produced more significant results on copepod abundance (up to 33%), which suggests that carnivorous gelatinous zooplankton may even modulate (control) the abundance of some species as well as the size structure of the copepod community.
机译：在2000年10月至2002年12月期间，在智利北部（Mejillones湾； 23°S）附近的上升流系统中研究了浮游动物食物网的结构及其主要碳通量。高初级生产力（PP）速率（1-8 gC m〜（ -2）d〜（-1））主要是由于浮游植物的净粒径分数（> 23μm）。传统上，高PP与赤道地下水的风流上升施肥作用有关，这有利于发展以短小楔形鱼类为主的短食物链。本工作的目的是研究通过“经典链”第一步（从浮游植物到主要消费者，如co足类和e虾类）的营养碳流，以及通过过滤器进料和过滤的碳流向凝胶状网的碳流。食肉性浮游动物。为了实现这一目标，使用天然存在的浮游生物捕食者组合对co足类，附肢动物，足类和棘足类动物进行了喂养实验。在整个研究过程中，总碳摄入速率表明，优势附生菌种和小pe足类动物分别平均消耗ind〜（-1）d〜（-1）的7和5μgC。此外，co足类主要在纳米和微浮游生物的大小范围内摄取颗粒，而阑尾虫则在微微和纳米浮游生物的范围内摄取。小co足虫和阑尾虫去除了每日总PP的一小部分（范围为6-11％）。但是，当皮克+纳米浮游生物组分是总PP（贫营养条件）的主要贡献者时，小co足类的放牧显着增加到总PP的86％。在这些更富营养的条件下，e草的放牧也增加了，但仅达到了总PP的5％以下。在这项研究中，石嘴鱼和eno足动物分别平均摄取了indd（（-1）d〜（-1）1和14个co足类。就消耗的生物量而言，食肉状胶状浮游动物对小型co足类群落（首选猎物）的潜在影响非常重要（每天清除2-12％的生物量）。然而，它们的影响对co足类的丰度产生了更显着的结果（高达33％），这表明食肉性胶状浮游动物甚至可以调节（控制）某些物种的丰度以及co足类群落的大小结构。

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