Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics (IBED-AEE), University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam, The Netherlands.
Environ Pollut. 2013 Sep;180:131-5. doi: 10.1016/j.envpol.2013.05.027. Epub 2013 Jun 5.
Toxicants potentially decouple links between biodiversity and ecosystem processes. This study aimed to evaluate how toxicants affect invertebrate bioturbation and decomposition. Effects of copper on functionally distinct macrofaunal species (Asellus aquaticus and Tubifex spp.), decomposition (release of dissolved organic carbon, DOC) and Average Metabolic Response (AMR) and Community Metabolic Diversity (CMD) of bacteria were determined in 5-day microcosm experiments. Bioturbation was assessed as sediment redox potential (Eh) profiles. Concentration-response curves of the functional parameters DOC, and the faunal mediated AMR and CMD in the presence of Tubifex spp. depended on Tubifex spp. survival, i.e. similar EC50 values for both endpoints. In contrast, functional parameters in the presence of A. aquaticus were more sensitive than survival. Sediment Eh-profiles showed that reduced decomposition was caused by reduced sediment reworking by A. aquaticus at sub-lethal copper concentrations. These observations hint at a decoupling of invertebrate community structure and ecosystem functioning upon stress.
有毒物质可能会破坏生物多样性和生态系统过程之间的联系。本研究旨在评估有毒物质如何影响无脊椎动物的生物搅动和分解。在为期 5 天的微宇宙实验中，确定了铜对功能不同的大型底栖动物物种（水生拟穴青蟹和颤蚓属）、分解（溶解有机碳的释放，DOC）以及细菌的平均代谢反应（AMR）和群落代谢多样性（CMD）的影响。生物搅动通过沉积物氧化还原电位（Eh）剖面进行评估。在颤蚓属存在的情况下，功能参数 DOC 的浓度-反应曲线，以及动物介导的 AMR 和 CMD，取决于颤蚓属的存活，即这两个终点的 EC50 值相似。相比之下，在水生拟穴青蟹存在的情况下，功能参数比生存更敏感。沉积物 Eh 剖面表明，在亚致死铜浓度下，水生拟穴青蟹减少了对沉积物的再作用，从而导致分解减少。这些观察结果表明，在受到压力时，无脊椎动物群落结构和生态系统功能可能会脱钩。
