Using complementary biomarkers to unravel fish lifetime exposure to hypoxia and mercury

Aquatic ecosystems are losing oxygen due to climate change. This deoxygenation can favor microbial methylation of mercury (Hg). To understand the dynamics of Hg under increasing deoxygenation, we simultaneously quantified both Hg and hypoxia (< 2 mg O2/L) lifetime chronologies in fishes. We used a novel combination of chemical biomarkers in ear stones and eye lenses of benthic Round Goby (Neogobius melanostomus) and semi-demersal Yellow Perch (Perca flavescens) from the Central Basin of Lake Erie and contrasted it with the less hypoxic but more polluted Western Basin. Overall, Central Basin Round Goby were exposed to hypoxia throughout their lifetime and exhibited significantly elevated eye lens Hg concentrations ([Hg]) compared to their Western Basin counterparts. In contrast, the Central Basin Yellow Perch were exposed to hypoxia only at their juvenile stage. Central Basin Yellow Perch exhibited significantly lower eye lens [Hg] compared to their Western Basin counterparts. Pattern..., , , # Using complementary biomarkers to unravel fish lifetime exposure to hypoxia and mercury

**Authors:** Hadis Miraly1,*, N. Roxanna Razavi1,*, Richard T. Kraus2, Ann Marie Gorman3, Elizabeth Duskey4, Matthew Altenritter5,†, and Karin E. Limburg1,6,*

**Affiliations**:

1State University of New York College of Environmental Science and Forestry, Syracuse, New York, United States

2U.S. Geological Survey, Great Lakes Science Center, Lake Erie Biological Station, Ohio, United States

3Fairport Fish Research Station, Ohio Department of Natural Resources, Fairport Harbor, Ohio, United States

4 Oklahoma State University, Department of Natural Resource Ecology and Management, Stillwater, Oklahoma, United States

5Department of Environmental Science and Ecology, State University of New York at Brockport, Brockport, New York, United States, †Deceased

6Department of Aquatic Resources, Swedish University of Agricultural Sciences, Uppsala, Sweden

*Corresponding authors: Hadis Miraly ([hmiraly@es...,