Macroalgal detritus and food-web subsidies along an Arctic fjord depth-gradient
Macroalgal detritus and food-web subsidies along an Arctic fjord depth-gradient
复制标题
DOI：
10.3389/fmars.2015.00031
复制
发表时间：
2015-06
影响因子：
3.7
通讯作者：
P. Renaud;T. S. Løkken;L. Jørgensen;J. Berge;Beverly J. Johnson
中科院分区：
文献类型：
--
作者：
P. Renaud;T. S. Løkken;L. Jørgensen;J. Berge;Beverly J. Johnson
在北极大陆架上，水层和底栖生物群落之间的紧密联系被认为是一项普遍原则。虽然这一模式已用于指导生态研究，它可能会导致不成比例的关注POM和冰藻作为最有可能的碳源的底栖食物网。北极大陆架是复杂的系统，包括浅滩、峡湾和深度达350米或更深的海槽系统。在这项稳定同位素研究中，分析了13种不同的潜在碳源对斯瓦尔巴群岛Isfjorden食物网的贡献。一个混合模式与食草桡足类和放牧海胆作为端员，以确定最有可能的碳源的相对贡献，浮游和底栖类群。大多数类群从底栖生物饲料的POM和大型藻类碎屑的广泛的混合物，甚至在深度下降到410米。大多数悬浮喂养的双壳类的同位素信号与海带和岩藻的50%以上的贡献一致。相比之下，几乎所有的中上层物种的饮食一致的中上层POM的压倒性的贡献。这些结果表明，大型藻类碎屑可以大大有助于近岸北极食物网，营养链，可能会增加，如果大型藻类在北极增加预测。沿海系统的中上层和底栖组成部分之间的数量联系较弱，突出表明在食物网研究中需要对潜在的碳基线进行彻底取样。北极底栖生物饮食中的大量碎屑碳成分可能会抑制极地初级生产者强烈的季节性影响，从而提高生态系统的复原力，但也可能导致次级生产力降低。
Tight coupling between pelagic and benthic communities is accepted as a general principle on Arctic shelves. Whereas this paradigm has been useful for guiding ecological research, it has perhaps led to a disproportionate focus on POM and ice algae as the most likely sources of carbon for the benthic food web. Arctic shelves are complex systems, including banks, fjords, and trough systems up to 350 m or more in depth. In this stable-isotope study, thirteen different potential carbon sources were analysed for their contribution to the food-webs of Isfjorden, Svalbard. A mixing model with herbivorous copepods and grazing sea urchins as end-members was applied to determine the relative contributions of the most likely carbon sources to pelagic and benthic taxa. Most taxa from the benthos feed on a broad mixture of POM and macroalgal detritus, even at depths down to 410 m. Most suspension-feeding bivalves had isotopic signals consistent with more than a 50% contribution from kelps and rockweeds. In contrast, nearly all pelagic species had diets consistent with an overwhelming contribution of pelagic POM. These results indicate that macroalgal detritus can contribute significantly to near-shore Arctic food-webs, a trophic link that may increase if macroalgae increase in the Arctic as predicted. These weaker quantitative links between pelagic and benthic components of coastal systems highlight the need for thorough sampling of potential carbon-baselines in food-web studies. A large detrital-carbon component in diets of Arctic benthos may dampen the impacts of strong seasonality in polar primary producers, leading to higher ecosystem resilience, but may also result in lower secondary productivity.