Amundsen Per-Arne, Henriksson Matilda, Poste Amanda, Prati Sebastian, Power Michael
Freshwater Ecology Group, Department of Arctic and Marine Biology, Faculty for Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway.
The Norwegian Institute for Water Research, Framsenteret, Tromsø, Norway.
Environ Toxicol Chem. 2023 Apr;42(4):873-887. doi: 10.1002/etc.5580. Epub 2023 Mar 10.
Mercury (Hg) is a serious concern for aquatic ecosystems because it may biomagnify to harmful concentrations within food webs and consequently end up in humans that eat fish. However, the trophic transfer of mercury through the aquatic food web may be impacted by several factors related to network complexity and the ecology of the species present. The present study addresses the interplay between trophic ecology and mercury contamination in the fish communities of two lakes in a pollution-impacted subarctic watercourse, exploring the role of both horizontal (feeding habitat) and vertical (trophic position) food web characteristics as drivers for the Hg contamination in fish. The lakes are located in the upper and lower parts of the watercourse, with the lower site located closer to, and downstream from, the main pollution source. The lakes have complex fish communities dominated by coregonids (polymorphic whitefish and invasive vendace) and several piscivorous species. Analyses of habitat use, stomach contents, and stable isotope signatures (δ N, δ C) revealed similar food web structures in the two lakes except for a few differences chiefly related to ecological effects of the invasive vendace. The piscivores had higher Hg concentrations than invertebrate-feeding fish. Concentrations increased with size and age for the piscivores and vendace, whereas habitat differences were of minor importance. Most fish species showed significant differences in Hg concentrations between the lakes, the highest values typically found in the downstream site where the biomagnification rate also was higher. Mercury levels in piscivorous fish included concentrations that exceed health authorization limits, with possible negative implications for fishing and human consumption. Our findings accentuate the importance of acquiring detailed knowledge of the drivers that can magnify Hg concentrations in fish and how these may vary within and among aquatic systems, to provide a scientific basis for adequate management strategies. Environ Toxicol Chem 2023;42:873-887. © 2023 SETAC.
汞（Hg）是水生生态系统面临的一个严重问题，因为它可能在食物网中生物放大至有害浓度，最终进入食用鱼类的人类体内。然而，汞在水生食物网中的营养转移可能会受到与网络复杂性及现存物种生态相关的若干因素影响。本研究探讨了受污染影响的亚北极水道中两个湖泊鱼类群落的营养生态学与汞污染之间的相互作用，探究水平（摄食栖息地）和垂直（营养级位置）食物网特征作为鱼类汞污染驱动因素的作用。这些湖泊位于水道的上游和下游，下游的湖泊距离主要污染源更近且在其下游。湖泊拥有复杂的鱼类群落，以白鲑科鱼类（多态白鲑和入侵的毛鳞鱼）和几种食鱼物种为主。对栖息地利用、胃内容物和稳定同位素特征（δN、δC）的分析表明，两个湖泊的食物网结构相似，只是存在一些差异，主要与入侵毛鳞鱼的生态影响有关。食鱼动物的汞浓度高于以无脊椎动物为食的鱼类。食鱼动物和毛鳞鱼的汞浓度随体型和年龄增加，而栖息地差异的影响较小。大多数鱼类物种在两个湖泊中的汞浓度存在显著差异；最高值通常出现在下游湖泊，那里的生物放大率也更高。食鱼鱼类的汞含量包括超过健康许可限值的浓度，这可能对捕鱼和人类消费产生负面影响。我们的研究结果强调了详细了解可放大鱼类汞浓度的驱动因素以及这些因素在水生系统内部和之间如何变化的重要性，以便为适当的管理策略提供科学依据。《环境毒理学与化学》2023年；42：873 - 887。© 2023 SETAC。
