USDA Forest Service, Northern Research Station, 1831 Highway 169 East, Grand Rapids, MN 55744, USA.
University of Minnesota, Department of Soil, Water, and Climate, 1991 Upper Buford Circle, Saint Paul, MN 55108, USA.
Sci Total Environ. 2019 Mar 15;656:475-481. doi: 10.1016/j.scitotenv.2018.11.280. Epub 2018 Nov 22.
Identifying what determines fish mercury (Hg) bioaccumulation remains a key scientific challenge. While there has been substantial research on spatial variation in fish Hg bioaccumulation, the factors that influence temporal fluctuations in fish Hg have received less attention to date. In this study, we built upon a growing body of research investigating young-of-the-year (YOY) yellow perch Hg bioaccumulation and investigated annual fluctuations in YOY yellow perch Hg in six lakes in northeastern Minnesota over eight years. After accounting for spatial variation between the study lakes, we used model averaging to identify the lake physiochemical and climate factors that best explain temporal variation in fish biomass and fish Hg. Fish biomass of YOY yellow perch had a positive relationship with chlorophyll-α and total Kjeldahl nitrogen and a negative relationship with dissolved iron and dissolved oxygen. There was a positive relationship between annual variation in yellow perch Hg concentration and annual variation in lake total suspended solids, dissolved Fe and pH. Additionally, there was a negative relationship between fish Hg concentration and lake total Kjeldahl nitrogen and growing degree days. Together, our results suggest that annual variation in allochthonous inputs from the watershed, in-lake processes, and climate variables can explain temporal patterns in Hg bioaccumulation and growth biodilution is an important process controlling yellow perch Hg concentrations.
确定哪些因素决定鱼类汞（Hg）的生物积累仍然是一个关键的科学挑战。尽管已经有大量关于鱼类 Hg 生物积累空间变化的研究，但迄今为止，影响鱼类 Hg 时间波动的因素受到的关注较少。在这项研究中，我们在研究幼鱼（YOY）黄鲈 Hg 生物积累的大量研究基础上进行了扩展，并在 8 年内调查了明尼苏达州东北部 6 个湖泊中 YOY 黄鲈 Hg 的年度波动。在解释了研究湖泊之间的空间变化后，我们使用模型平均法确定了最佳解释鱼类生物量和鱼类 Hg 时间变化的湖泊理化和气候因素。YOY 黄鲈的鱼类生物量与叶绿素-α和总凯氏氮呈正相关，与溶解铁和溶解氧呈负相关。黄鲈 Hg 浓度的年度变化与湖泊总悬浮物、溶解 Fe 和 pH 的年度变化呈正相关。此外，鱼类 Hg 浓度与湖泊总凯氏氮和生长度日数呈负相关。综上所述，我们的研究结果表明，来自流域的异源输入、湖泊内过程和气候变量的年度变化可以解释 Hg 生物积累的时间模式，生物稀释是控制黄鲈 Hg 浓度的一个重要过程。
