N. Roxanna Razavi

Fish eye lens chronologies reveal reservoir-driven changes in carbon biogeochemistry and mercury bioaccumulation

Annabelle Vogl, Dominic E. Ponton, N. Roxanna Razavi, Karin E. Limburg et autres

Reservoir impoundments alter river carbon (C) biogeochemistry as submerged terrestrial material is decomposed, which enhances mercury (Hg) methylation. Methylmercury (MeHg) is a neurotoxin that bioaccumulates in aquatic organisms and biomagnifies along food webs, exposing wildlife and human consumers. Reservoir characteristics (ie., water …

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Evaluation of the BenthoTorch using lake periphyton: A comparison of attached cyanobacterial biomass estimates

Abby M. Webster, Trevor Massey, Lisa B. Cleckner, Gregory L. Boyer et autres

Abstract Simple monitoring methods for benthic cyanobacteria are lacking, especially in lentic systems. Traditional methods to estimate biomass, such as Chlorophyll‐ a or phycocyanin measurements, are complicated by benthic cyanobacteria's ability to adapt under variable light conditions. In response, benthic cyanobacteria adjust …

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Per- and polyfluoroalkyl substances (PFAS) in wild amphibians: a call for more research

J Tennant, Sujan Fernando, Eric Levanduski, Sydney L Burgy et autres

Amphibians serve a central role in food webs and provide a link between aquatic and terrestrial habitats. Because of their dependence on water, amphibians are susceptible to legacy and emerging contaminants. We investigated mercury (Hg) and per- and polyfluoroalkyl substances (PFAS) concentrations …

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First report of nodularin production by Nostochopsis sp. in a temperate eutrophic lake

Abby M. Webster, Zac Triumph, Bofan Wei, Robbie M. Martin et autres

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A novel artificial intelligence–powered cell counting tool coupled with digital microscopy for rapid field‐assessment of harmful cyanobacterial blooms

Igor Mrdjen, Zacharias J. Smith, Abby M. Webster, Christopher C. Nack et autres

ABSTRACT Historical quantification of cyanobacterial harmful algal blooms (cHABs) typically involved labor‐intensive manual cell counting. We developed a novel, cost‐effective, field‐validated system to perform cell counts of six common toxin‐producing cyanobacterial genera within 30 s of upload with 10‐min sample preparation. Using …

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Integrating the Bright and Dark Sides of Aquatic Resource Subsidies—A Synthesis

Cornelia W. Twining, Andreu Blanco, Christopher L. Dutton, Martin J. Kainz et autres

Aquatic and terrestrial ecosystems are linked through the reciprocal exchange of materials and organisms. Aquatic-to-terrestrial subsidies are relatively small in most terrestrial ecosystems, but they can provide high contents of limiting resources that increase consumer fitness and ecosystem production. However, they also …

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First Retrospective Study of Avian Mercury Exposure in a Tropical ASGM Hotspot

Sarah A. Dzielski, Subir B. Shakya, Y A Mulyani, Mohammad Irham et autres

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Unique per- and polyfluoroalkyl substances (PFAS) source suggested by a Lake Trout (Salvelinus namaycush) PFAS profile in a temperate lake

Eric Levanduski, Susan F. Cushman, Lisa B. Cleckner, Wayne Richter et autres

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

Hadis Miraly, N. Roxanna Razavi, Richard T. Kraus, Ann Marie Gorman et autres

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−1) lifetime chronologies in fishes. We …

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Methylmercury Concentrations More Strongly Associated With Trait Variation Than Food Web Position in Plethodontid Salamanders

J Tennant, Bradley J. Cosentino, Lisa B. Cleckner, Kristen Brubaker et autres

Abstract Salamanders serve as bioindicators of mercury (Hg) in both terrestrial and aquatic habitats and are an important link in the food web between low-trophic prey and higher-trophic predators. We investigated the drivers of methylmercury (MeHg) exposure in three common plethodontid salamander …

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Two for the Price of One: Deriving Per- and Polyfluoroalkyl Substances (PFAS) Fillet and Whole-Body Conversion Equations in Fish

Eric Levanduski, Wayne Richter, Jesse C. Becker, Yasaman Hassanzadeh et autres

Per- and polyfluoroalkyl substances (PFAS) pose risks to both human and ecological health. Fish consumption advisories are typically based on fillet concentrations, whereas environmental risk assessment for biota depends on whole-body fish concentrations. Reliable equations for conversion between fillet and whole-body concentrations …

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A comparison of stable isotopes and polychlorinated biphenyls among genetic strains of Lake Ontario lake trout (Salvelinus namaycush)

Nicole E. Saavedra, N. Roxanna Razavi, Donald J. Stewart, Brian F. Lantry et autres

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