Recent Patterns in Lake Erie Phosphorus and Chlorophyll Concentrations in Response to Changing Loads.

Despite the initial success of extensive efforts to reduce phosphorus (P) loading to Lake Erie as a part of the Great Lakes Water Quality Agreement, Lake Erie appears to be undergoing a re-eutrophication and it is plagued by harmful algal blooms. To offer insights into potential lake responses under differing Maumee River loads and reveal recent changes with time, we explored patterns in phosphorus and chlorophyll data from 2008 to 2018 collected in western Lake Erie near the mouth of the Maumee River. We found high, but relatively stable Maumee River and lake concentrations of total P (TP) and soluble reactive P (SRP) with no discernable annual or seasonal patterns.

Reduced forms of nitrogen are a driver of non-nitrogen-fixing harmful cyanobacterial blooms and toxicity in Lake Erie.

Western Lake Erie (WLE) experiences anthropogenic eutrophication and annual, toxic cyanobacterial blooms of non-nitrogen (N) fixing Microcystis. Numerous studies have shown that bloom biomass is correlated with an increased proportion of soluble reactive phosphorus loading from the Maumee River. Long term monitoring shows that the proportion of the annual Maumee River N load of non-nitrate N, or total Kjeldahl nitrogen (TKN), has also increased significantly (Spearman's ρ = 0.

Ecophysiological Examination of the Lake Erie Microcystis Bloom in 2014: Linkages between Biology and the Water Supply Shutdown of Toledo, OH.

Annual cyanobacterial blooms dominated by Microcystis have occurred in western Lake Erie (U.S./Canada) during summer months since 1995.

Challenges for mapping cyanotoxin patterns from remote sensing of cyanobacteria.

Using satellite imagery to quantify the spatial patterns of cyanobacterial toxins has several challenges. These challenges include the need for surrogate pigments - since cyanotoxins cannot be directly detected by remote sensing, the variability in the relationship between the pigments and cyanotoxins - especially microcystins (MC), and the lack of standardization of the various measurement methods. A dual-model strategy can provide an approach to address these challenges.

Cyanobacterial harmful algal blooms are a biological disturbance to Western Lake Erie bacterial communities.

Human activities are causing a global proliferation of cyanobacterial harmful algal blooms (CHABs), yet we have limited understanding of how these events affect freshwater bacterial communities. Using weekly data from western Lake Erie in 2014, we investigated how the cyanobacterial community varied over space and time, and whether the bloom affected non-cyanobacterial (nc-bacterial) diversity and composition. Cyanobacterial community composition fluctuated dynamically during the bloom, but was dominated by Microcystis and Synechococcus OTUs.

A kinetic study of accumulation and elimination of microcystin-LR in yellow perch (Perca flavescens) tissue and implications for human fish consumption.

Fish consumption is a potential route of human exposure to the hepatotoxic microcystins, especially in lakes and reservoirs that routinely experience significant toxic Microcystis blooms. Understanding the rates of uptake and elimination for microcystins as well as the transfer efficiency into tissues of consumers are important for determining the potential for microcystins to be transferred up the food web and for predicting potential human health impacts. The main objective of this work was to conduct laboratory experiments to investigate the kinetics of toxin accumulation in fish tissue.

Predicting bioavailability of sediment-associated organic contaminants for Diporeia spp. and oligochaetes.

Biota-sediment accumulation factors (BSAF) were calculated for Diporeia spp. and oligochaete worms exposed to polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from field-collected sediment. These data were compared to the contaminant fraction extracted from sediment with Tenax resin using a 24 h extraction.

The contrasting roles of sedimentary plant-derived carbon and black carbon on sediment-spiked hydrophobic organic contaminant bioavailability to Diporeia species and Lumbriculus variegatus.

In bioavailability studies, the biota sediment accumulation factor (BSAF) is invoked to describe the thermodynamic partitioning of a hydrophobic organic contaminant (HOC) between the organism lipid and the organic carbon fraction of the sedimentary matrix and accounts for differences in bioavailability among sediments. Bioaccumulation experiments were performed with Lumbriculus variegatus and Diporeia species exposed in seven sediments dosed with 2,4,5,2',4',5'-hexachlorobiphenyl (HCBP) and benzo[a]pyrene (BaP) or pyrene (PY) and 3,4,3',4'-tetrachlorobiphenyl (TCBP). The BSAF values for the nonplanar HCBP were consistent with equilibrium partitioning theory (EQP) and averaged 2.

Time-dependent toxicity of dichlorodiphenyldichloroethylene to Hyalella azteca.

Temporal effects on body residues of dichlorodiphenyldichloroethylene (DDE) associated with mortality in the freshwater amphipod Hyalella azteca were evaluated. Toxicokinetics and body residues were determined from water-only exposures that varied from 4 to 28 d, and DDE concentrations ranging from 0.0013 to 0.

The role of desorption for describing the bioavailability of select polycyclic aromatic hydrocarbon and polychlorinated biphenyl congeners for seven laboratory-spiked sediments.

Lumbriculus variegatus and Diporeia spp. were exposed to two contaminant pairs 3H-benzo[a]pyrene (BaP) and 14C-2,4,5,2'4',5'-hexachlorobiphenyl (HCBP), and 3H-pyrene (PY) and 14C-3,4,3',4'-tetrachlorobiphenyl (TCBP) sorbed to each of seven field-collected sediments of varying composition. Toxicokinetic coefficients, bioaccumulation factors (BAF), and biota-sediment accumulation factors ([BSAF], BAF normalized to the organism lipid content and sediment organic carbon content) were determined.

Time-dependent lethal body residues for the toxicity of pentachlorobenzene to Hyalella azteca.

The study examined the temporal response of Hyalella azteca to pentachlorobenzene (PCBZ) in water-only exposures. Toxicity was evaluated by calculating the body residue of PCBZ associated with survival. The concentration of PCBZ in the tissues of H.

Comparing behavioral and chronic endpoints to evaluate the response of Lumbriculus variegatus to 3,4,3',4'-tetrachlorobiphenyl sediment exposures.

The response of Lumbriculus variegatus to 3,4,3',4'-tetrachlorobiphenyl (TCBP) was examined with feeding behavior and changes in carbon assimilation by using stable carbon isotopes at 22 and 10 degrees C. The classical measure of feeding behavior determined on a subset of sediment for which the biological burial rate was determined in a companion study allowed direct method comparison. This comparison helped address relationships between biological burial rate, feeding rate, and bioaccumulation.

Effect of 3,4,3',4'-tetrachlorobiphenyl on the reworking behavior of Lumbriculus variegatus exposed to contaminated sediment.

The reworking response (bioturbation) of the oligochaete Lumbriculus variegatus was measured by following the burial rate and spread of a 137Cs marker layer translating worm activity into a biological burial rate (Wb) and a biological diffusion rate constant (Db) for surficial sediment mixing. Reworking was measured at 10 and 22 degrees C in two sediments: a reference site sediment dosed with 3,4,3',4'-tetrachlorobiphenyl (TCBP) and a field-collected sediment from a polychlorinated biphenyl (PCB)-contaminated site in Dicks Creek (DCC, Middletown, OH, USA). The body residue associated with response to TCBP also was determined.

Investigating the role of desorption on the bioavailability of sediment-associated 3,4,3',4'-tetrachlorobiphenyl in benthic invertebrates.

Only a fraction of all sediment-associated hydrophobic organic contaminants are bioavailable, and a simple Tenax extraction procedure may estimate this fraction. Bioavailability is assumed to coincide with the rapidly and, possibly, slowly desorbing sediment-associated contaminant. River sediment was spiked with radiolabeled (14C) and nonradiolabeled (12C) 3,4,3',4'-tetrachlorobiphenyl (TCBP), and desorption kinetics using Tenax extraction were obtained at 10 degrees C and 22 degrees C.

Bioaccumulation and critical body residue of PAHs in the amphipod, Diporeia spp: additional evidence to support toxicity additivity for PAH mixtures.

Polycyclic aromatic hydrocarbons (PAHs) are considered to act additively when exposed as congener mixtures. Additive internal concentrations at the site of toxic action is the basis for recent efforts to establish a sum PAH guideline for sediment-associated PAH toxicity. This study determined the toxicity of several PAH congeners on a body residue basis in Diporeia spp.