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Articles published in professional journals written as a result of Sea Grant sponsored projects

These reprints are articles published in professional and academic journals written as a result of Sea Grant sponsored projects.


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Nitrification in the water column of Lake Erie: Seasonal patterns, community dynamics, and competition with cyanobacterial harmful algal blooms

OHSU-RS-1614
Nitrification in the water column of Lake Erie: Seasonal patterns, community dynamics, and competition with cyanobacterial harmful algal blooms
ABSTRACT:

This study reports directly measured nitrification rates in the water column of western Lake Erie, which is affected by annual cyanobacterial harmful algal blooms, and across all three Lake Erie basins. Over three field seasons, 15NH4 + stable isotope tracers were employed to quantify nitrification rates, and relative abundances of ammonia-oxidizing bacteria and ammonia-oxidizing archaea were determined via qPCR. Nitrification rates ranged from undetectable to 1,270 nmol L-1 d-1 and were generally greatest in the western basin near the Maumee River mouth (a major nutrient source). Nitrification rates were highest in early summer, and often lowest during peak cyanobacterial harmful algal blooms months (August and September), before increasing again in October. In the western basin, nitrification was negatively correlated with cyanobacterial biomass. There were no consistent differences in nitrification rates between the three Lake Erie basins. Over the three years in western Lake Erie, ammonia-oxidizing bacteria and ammonia-oxidizing archaea were often present in high and similar abundances, but overall, ammonia-oxidizing bacteria exceeded ammonia-oxidizing archaea, particularly in 2017. No relationships were observed between nitrification rates and ammonia-oxidizing bacteria and ammonia-oxidizing archaea abundances. Thus, despite abundant ammonia-oxidizer DNA, lower nitrification rates during cyanobacterial harmful algal blooms suggest that nitrifiers were poor competitors for regenerated and available NH4 + during these blooms, as also observed in similar systems. Low nitrification rates during cyanobacterial harmful algal blooms could limit system nitrogen removal via denitrification, a natural pathway for its removal and a valuable ecosystem service. Lower denitrification rates allow more bioavailable nitrogen to remain in the system and support biomass and microcystin production; therefore, these results help explain how non-nitrogen-fixing cyanobacterial harmful algal blooms persist, despite low bioavailable nitrogen concentrations during these blooms, and support management efforts to reduce external nitrogen loading to eutrophic systems.

DOI: https://doi.org/10.14321/aehm.026.04.43 VOLUME: 26 ISSUE: 4

Climate Change Effects on Rainfall Intensity–Duration–Frequency (IDF) Curves for the Lake Erie Coast Using Various Climate Models

OHSU-RS-1613
Climate Change Effects on Rainfall Intensity–Duration–Frequency (IDF) Curves for the Lake Erie Coast Using Various Climate Models
ABSTRACT:

This study delved into the analysis of hourly observed as well as future precipitation data in the towns of Willoughby and Buffalo on the Lake Erie Coast to examine the variations in IDF relationships over the 21st century. Several regional climate models (RCMs) and general circulation models (GCMs) from the Coupled Model Intercomparison Project (CMIP) Phases 5 and 6 were used. The study evaluated three RCMs with historical and Representative Concentration Pathway (RCP) 8.5 scenarios for each CMIP5 and three GCMs with historical and Shared Socioeconomic Pathways (SSPs) (126, 245, 370, and 585) scenarios for each CMIP6. The results suggested that the town of Willoughby would experience an increase of 9–46%, whereas Buffalo would experience an upsurge of 6–140% in the hourly precipitation intensity under the worst-case scenarios of RCP8.5 for CMIP5 and SSP585 for CMIP6. This increase is expected to occur in both the near (2020–2059) and far future (2060–2099), with a return period as low as 2 years and as high as 100 years when compared to the baseline period (1980–2019). The analysis indicated an increased range of 9–39% in the near future and 20–55% in the far future for Willoughby, while the Buffalo region may experience an increase of 2–95% in the near future and 3–192% in the far future as compared to the baseline period. In contrast to CMIP6 SSP585 models, CMIP5 RCP8.5 models predicted rainfall with an intensity value that is up to 28% higher in the town of Willoughby, while the reverse was true for the Buffalo region. The findings of this study are expected to be helpful for the design of water resource infrastructures.

DOI: https://doi.org/10.3390/w15234063 VOLUME: 15 ISSUE: 23

A Case Series of Potential Pediatric Cyanotoxin Exposures Associated with Harmful Algal Blooms in Northwest Ohio

OHSU-RS-1606
A Case Series of Potential Pediatric Cyanotoxin Exposures Associated with Harmful Algal Blooms in Northwest Ohio
ABSTRACT:

Cyanobacterial harmful algal blooms (CyanoHABs) are increasing in prevalence and severity globally and locally in the Great Lakes region. CyanoHABs have the potential to produce serious adverse human health effects due to the production of cyanotoxins from cyanobacteria. Common routes of exposure include recreational exposure (swimming, skiing, and boating), ingestion, and aerosolization of contaminated water sources. Cyanotoxins have been shown to adversely affect several major organ systems contributing to hepatotoxicity, gastrointestinal distress, and pulmonary inflammation. We present three pediatric case-reports that coincided with CyanoHABs exposure with a focus on presentation of illness, diagnostic work-up, and treatment of CyanoHAB-related illnesses. Potential cyanotoxin exposure occurred while swimming in the Maumee River and Maumee State Park in Northwest OH during the Summer months which coincide with peak CyanoHAB activity. Primary symptoms included generalized macular rash, fever, vomiting, diarrhea, and severe respiratory distress. Significant labs included leukocytosis and elevated C-reactive protein. All patients ultimately recovered with supportive care. Symptoms following potential cyanotoxin exposure coincide with multiple disease states representing an urgent need to develop specific diagnostic tests of exposure.

Constraining carbon and sulfur dynamics in Lake Erie nearshore waters: A chemical and isotopic reconnaissance study

OHSU-RS-1612
Constraining carbon and sulfur dynamics in Lake Erie nearshore waters: A chemical and isotopic reconnaissance study
ABSTRACT:

Past studies have documented contrasting geochemical responses of the Great Lakes to anthropogenic disturbances of the carbon and sulfur cycles. Yet, it is unclear whether these responses were induced by differences in tributary inputs or different behaviors controlled by in-lake biogeochemical processes. To yield insight into the carbon and sulfur dynamics across the land-lake interface, concentrations of chloride (Cl-), sulfate (SO42-), dissolved inorganic carbon (DIC), and dissolved organic carbon (DOC) were measured in water samples from nearshore and offshore sites at Lake Erie, the Detroit River, and other tributaries. The stable isotope ratios of water (δ18O and δ2H), sulfate (δ34SSO4 and δ18OSO4), and the stable and radio isotope ratios of DIC (δ13CDIC and Δ14CDIC) were also measured. Our results confirm that waters from Lake Erie characterized by low Cl- and SO42-, low deuterium excess (d-excess = δ2H – 8 δ18O), and high δ13CDIC, Δ14CDIC, δ34SSO4, and δ18OSO4, were chemically and isotopically different from tributary waters. The nearshore waters exhibited significant correlations between various pairs of chemical and isotopic parameters revealing the influence of inputs from the tributaries. Moreover, the nearshore waters had lower averages of Cl-, SO42-, DOC, DIC, and δ18O, but higher averages of δ13CDIC, Δ14CDIC, and δ34SSO4 than those estimated from binary mixing between lake and tributary waters, suggesting an effect of in-lake biogeochemical transformations. But the rates of carbon and sulfur transformations differed considerably. Thus, we suggest that the contrasting geochemical responses were induced by both their different in-lake transformation rates and their different histories of tributary inputs.

DOI: https://doi.org/10.1016/j.jglr.2023.07.005 VOLUME: 49 ISSUE: 5 LENGTH: 13 pages

Forecasting microcystin concentrations in Lake Erie using an Eulerian tracer model

OHSU-RS-1610
Forecasting microcystin concentrations in Lake Erie using an Eulerian tracer model
ABSTRACT:

Cyanobacteria biomass models are routinely used in Lake Erie to predict the occurrence and location of algal blooms. However, current forecasts do not predict the microcystin toxins produced by these blooms. In this study, we used an extensive dataset of microcystin concentrations to generate weekly distribution maps in Lake Erie for the summers of 2018 and 2019. Using a 3D Eulerian tracer model (ETM) initialized with these maps, we simulated microcystin transport over 7 days, under two conditions: (1) the initial microcystin is mixed within the surface-mixed layer; (2) the initial microcystin is distributed throughout the entire water column. Two scenarios were tested for each condition: one incorporating microcystin production rates into hydrodynamic transport and one excluding them. Model performance was evaluated against weekly sample data in predicting whether microcystin concentrations surpassed specific thresholds (0.3, 1.0, 5.0, 10.0, and 20.0 µg/L), and in predicting trend directionality over each week. Overall, the ETM with hydrodynamics alone captured the transport of microcystins and predicted microcystin concentrations in 69% of the simulations. Incorporating microcystin production into the model increased the accuracy of forecasts by an additional 10%. Moreover, models with microcystin production successfully predicted microcystin concentrations greater than 5 μg/L during a large bloom, high-microcystin year (2019), while incorrectly forecasting concentrations above 5 μg/L during a small bloom year (2018). With limited data to initialize the ETM, no single model configuration consistently outperformed others. It is necessary to consider the full range of model configurations when utilizing their outputs for making management decisions.

DOI: https://doi.org/10.1016/j.jglr.2023.06.006 VOLUME: 49 ISSUE: 5 LENGTH: 15 pages

Introduction to the special section: Status and approaches to assess Lake Erie Central Basin hypoxia

OHSU-RS-1616
Introduction to the special section: Status and approaches to assess Lake Erie Central Basin hypoxia
ABSTRACT:

Seasonal hypolimnetic hypoxia has occurred in Lake Erie’s central basin since at least the 1950s. The 2012 Great Lakes Water Quality Agreement includes a lake ecosystem objective that commits Canada and the United States to minimize the extent of hypoxic zones, with a particular emphasis on Lake Erie. To meet that objective, Canada and the United States adopted a 40% total phosphorus load reduction target for the western and central basins of the lake. To help assess progress in minimizing Lake Erie’s hypoxic zones, the Cooperative Institute for Great Lakes Research (CIGLR) convened a virtual summit in October 2021 to update the state-of-knowledge regarding hypoxia in Lake Erie. This special section summarizes the recommendations for monitoring, assessment, modeling and reporting of hypoxia that resulted from the workshop and features five papers that present new information about hypoxia in Lake Erie. Recognizing that hypoxia occurs in other areas within the Great Lakes basin, a paper investigating seasonal drivers of hypoxia dynamics in Muskegon Lake a drowned river mouth that flows into Lake Michigan, is also featured.

DOI: https://doi.org/10.1016/j.jglr.2023.08.005 VOLUME: 49 ISSUE: 5 LENGTH: 3 pages

Microcystin congeners in Lake Erie follow the seasonal pattern of nitrogen availability

OHSU-RS-1609
Microcystin congeners in Lake Erie follow the seasonal pattern of nitrogen availability
ABSTRACT:

Cyanobacteria harmful algal blooms produce many toxic secondary metabolites called cyanotoxins. The most studied group of cyanotoxins are microcystins (MC), with over 300 congeners reported. MC-LR is the most studied congener because of its abundance and toxicity. Recent toxicology studies suggest that more hydrophobic MC congeners such as MC-LA, MC-LF, and MC-LW may be less abundant but up to seven times more toxic than MC-LR, whereas, MC-RR’s toxicity is only one-fifth that of MC-LR. Hence, understanding the environmental stressors that change the MC congener profile is critical to assessing the negative impact on environmental and human health. A two-year field and experimental study investigated seasonal and spatial changes of MC congener profiles in the western basin of Lake Erie. Both studies showed that nitrogen enrichment favored the production of nitrogen-rich MC-RR (C49H75N13O12). The field study showed that nitrogen depletion favored the low-nitrogen MC-LA (C46H67N7O12). MC-LR (a medium N level, C49H75N10O12) accounted for ∼30% to 50% of the total MC concentration and was stable across nitrogen concentrations. Using the relative toxicity and concentrations of each MC congener, both LC-MS/MS and ELISA overestimated the toxicity early bloom (July) and underestimated it late bloom (September). On 24 July 2019, highly toxic MC-LW and MC-LF were detected at nearshore stations with relative toxicity exceeding drinking water standards. This study demonstrated that the less toxic, high nitrogen MC-RR dominated under nitrogen-replete conditions in the early season, whereas the more toxic, less nitrogen MC-LA dominated under nitrogen-limited conditions later in the season.

Agricultural conservation practices could help offset climate change impacts on cyanobacterial harmful algal blooms in Lake Erie

OHSU-RS-1608
Agricultural conservation practices could help offset climate change impacts on cyanobacterial harmful algal blooms in Lake Erie
ABSTRACT:

Harmful algal blooms (HABs) are a recurring problem in many temperate large lake and coastal marine ecosystems, caused mainly by anthropogenic eutrophication. Implementation of agricultural conservation practices (ACPs) offers a means to reduce non-point source nutrient runoff and mitigate HABs. However, the effectiveness of ACPs in a changing climate remains uncertain. We used an integrated biophysical modeling approach to predict how Lake Erie cyanobacterial HAB severity (bloom biomass) may change under several climate and ACP implementation scenarios, using western Lake Erie and its largely agricultural watershed as our study system. An ensemble of general circulation model projections was used to drive spatially explicit land use and hydrology models of the Maumee River watershed, the output of which informed a predictive model of Lake Erie HAB severity. Results show that, in the absence of changes in ACPs, the frequency of severe HABs is projected to increase during coming decades, owing to increased inputs of nutrients from the watershed. These anticipated increases are due to increased total precipitation and more frequent higher-magnitude rainfall events. While further implementation of ACPs appears capable of reducing severe HAB events, widespread implementation would be necessary to reduce HAB severity below current management targets. This study highlights how continued climate change will only exacerbate the need for land management practices that can reduce nutrient runoff in agriculturally dominated ecosystems, such as Lake Erie. It also shows how interdisciplinary, biophysical modeling approaches can help identify strategies to mitigate HABs in the face of anthropogenic stressors.

DOI: https://doi.org/10.1016/j.jglr.2022.11.009 VOLUME: 49 ISSUE: 1 LENGTH: 10 pages

Measuring beachgoer preferences for avoiding harmful algal blooms and bacterial warnings

OHSU-RS-1607
Measuring beachgoer preferences for avoiding harmful algal blooms and bacterial warnings
ABSTRACT:

This paper estimates beachgoers’ preferences for beach quality, including avoidance of harmful algal blooms and bacterial warnings. Following a stratified random sampling schedule, data was collected via interviews conducted at 28 public beaches from Eastern Ohio to Northern Lake St Clair. Randomly selected visitors were interviewed and sent a follow-up choice experiment survey, which measured preferences for beach attributes. We find the average respondent is willing to drive 260 and 266 miles to avoid sites with either current HAB or bacterial warnings, and find a negative stigma effect that remains at least 6 days post-warning. While respondents’ aversion to active HAB and bacterial warnings are not statistically different, this aversion decreases more slowly after a bacterial warning; respondents are willing to drive 77 miles to avoid a site with a bacterial warning lifted 6 days earlier, but only 31 miles to avoid a site with a HAB warning lifted 6 days earlier. To test our findings’ validity, we used the choice model estimates to simulate responses to contingent behavior questions from the follow-up. Although framed differently, the elicitation formats yield concordant findings. Results indicate that cost-benefit analysis which doesn’t evaluate the stigma effect of recently-lifted warnings may understate their costs.

GeneToList: A Web Application to Assist with Gene Identifiers for the Non-Bioinformatics-Savvy Scientist

OHSU-RS-1615
GeneToList: A Web Application to Assist with Gene Identifiers for the Non-Bioinformatics-Savvy Scientist
ABSTRACT:

The increasing incorporation of omics technologies into biomedical research and translational medicine presents challenges to end users of the large and complex datasets that are generated by these methods. A particular challenge in genomics is that the nomenclature for genes is not uniform between large genomic databases or between commonly used genetic analysis tools. Furthermore, outdated genomic nomenclature can still be found amongst scientific communications, including peer-reviewed manuscripts. Therefore, a web application (GeneToList) was developed to assist in gene ID conversion and alias matching, with a specific focus on achieving a user-friendly interface for the non-bioinformatics-savvy scientist. It currently includes gene information for over 38,000 different taxa retrieved from the National Center for Biotechnology and Information (NCBI) Gene resource. Supported databases of gene IDs include NCBI Gene Symbols, NCBI Gene IDs (Entrez IDs), OMIM IDs, HGNC IDs, Ensembl IDs, and 28 other taxa-specific identifiers. GeneToList is available at genetolist.com. The tool is a web application that is compatible with many standard browsers. The gene ID conversion feature of this application was found to outcompete the common gene ID conversion tools. Specifically, it was able to successfully convert all tested IDs, whereas the others were not able to recognize the gene aliases. Therefore, the gene ID disambiguation provided by this application should be beneficial for many scientists dealing with gene data when the uniformity of gene nomenclature is important for downstream analysis.

The role of internal nitrogen loading in supporting non-N-fixing harmful cyanobacterial blooms in the water column of a large eutrophic lake

OHSU-RS-1611
The role of internal nitrogen loading in supporting non-N-fixing harmful cyanobacterial blooms in the water column of a large eutrophic lake
ABSTRACT:

Western Lake Erie cyanobacterial harmful algal blooms (cyanoHABs) occur every summer as a result of anthropogenic nutrient loading. Although the physiological importance of nitrogen (N) in supporting bloom biomass and toxin production is established, the role of internal N recycling in the water column to support bloom maintenance is not as well understood. Over three field seasons (2015–2017), we collected water from western Lake Erie and employed bottle incubations with 15N-ammonium (NH4) enrichments to determine (NH4) regeneration and potential uptake rates in the water column. Potential (NH4) uptake rates followed spatial and seasonal patterns, with greatest rates measured nearest the Maumee River inflow and during peak bloom months (August and September). Regeneration followed a similar spatial pattern but was greatest in early summer (June and July) and supported ~ 20–60% of potential NH4 demand during the height of the bloom. Basin-wide internal NH4 regeneration during the April–October period could supply NH4 at 60–200% of annual external N loading to the western basin. These results help explain how non-N-fixing cyanoHABs in Lake Erie and other large, eutrophic lakes continue producing biomass and N-rich toxins long after spring nutrient loads are exhausted or transported to other areas. Internal N loads are ultimately driven by external N loads; in low precipitation years, external nutrient loads result in smaller blooms, producing less substrate for subsequent internal N loads. Overall, these findings, along with others, confirm that both internal and external N loading must be considered when evaluating cyanoHAB management strategies.

DOI: https://doi.org/10.1002/lno.12185 VOLUME: 67 ISSUE: 9 LENGTH: 13 pages

Farmers Markets and Single-Use Plastic: Why Environmentally Conscious Consumers Don’t Bring Reusable Bags

OHSU-RS-1605
Farmers Markets and Single-Use Plastic: Why Environmentally Conscious Consumers Don’t Bring Reusable Bags
ABSTRACT:

This study looks at the role of Extension in helping local officials reduce plastic bag use at farmers markets in three Lake County, OH communities. We distributed free reusable bags to shoppers and conducted an education and outreach program. We then took observations to determine if the free reusable bags were being used. We also invited shoppers to take a voluntary survey about their environmental attitudes, why or why not they use the reusable bags, and how best to reduce plastic bag use moving forward. Results from the study suggest that supplying free reusable bags at farmer markets is not an effective strategy for Extension professionals attempting to reduce plastic bag use. Instead, we recommend working with local officials to develop financial incentives and disincentives tied to the type of bag option shoppers use, implement plastic bag bans at markets, and conduct locally-focused education and outreach. Although shoppers’ environmental literacy and desire for sustainability is high, it is shown that behavior change is unlikely to occur without financial or policy incentives.

Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size

OHSU-RS-1524
Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size
ABSTRACT:

Body size, and, by extension, growth has impacts on physiology, survival, attainment of sexual maturity, fecundity, generation time, and population dynamics, especially in ectotherm animals that often exhibit extensive growth following attainment of sexual maturity. Frequently, growth is analyzed at the population level, providing useful population mean growth parameters but ignoring individual variation that is also of ecological and evolutionary significance. Our long-term study of Lake Erie Watersnakes, Nerodia sipedon insularum, provides data sufficient for a detailed analysis of population and individual growth. We describe population mean growth separately for males and females based on size of known age individuals (847 captures of 769 males, 748 captures of 684 females) and annual growth increments of individuals of unknown age (1,152 males, 730 females). We characterize individual variation in asymptotic size based on repeated measurements of 69 males and 71 females that were each captured in five to nine different years. The most striking result of our analyses is that asymptotic size varies dramatically among individuals, ranging from 631–820 mm snout-vent length in males and from 835–1125 mm in females. Because female fecundity increases with increasing body size, we explore the impact of individual variation in asymptotic size on lifetime reproductive success using a range of realistic estimates of annual survival. When all females commence reproduction at the same age, lifetime reproductive success is greatest for females with greater asymptotic size regardless of annual survival. But when reproduction is delayed in females with greater asymptotic size, lifetime reproductive success is greatest for females with lower asymptotic size when annual survival is low. Possible causes of individual variation in asymptotic size, including individual- and cohort-specific variation in size at birth and early growth, warrant further investigation.

DOI: 10.5061/dryad.fk71c VOLUME: 11 ISSUE: 1 LENGTH: 15 pages

Short Winters Threaten Temperate Fish Populations

OHSU-RS-1519
Short Winters Threaten Temperate Fish Populations
ABSTRACT:

Although climate warming is expected to benefit temperate ectotherms by lengthening the summer growing season, declines in reproductive success following short, warm winters may counter such positive effects. Here we present long-term (1973–2010) field patterns for Lake Erie yellow perch,Perca flavescens, which show that failed annual recruitment events followed short, warm winters. Subsequent laboratory experimentation and field investigations revealed how reduced reproductive success following short, warm winters underlie these observed field patterns. Following short winters, females spawn at warmer temperatures and produce smaller eggs that both hatch at lower rates and produce smaller larvae than females exposed to long winters. Our research suggests that continued climate warming can lead to unanticipated, negative effects on temperate fish populations.

DOI: 10.1038/ncomms8724 VOLUME: 6 LENGTH: 9 pages

Feeding Ecology of the Invasive Round Goby, Neogobius melanostomus (Pallas, 1814), Based on Laboratory Size Preference and Field Diet in Different Habitats in the Western Basin of Lake Erie

OHSU-RS-1523
Feeding Ecology of the Invasive Round Goby, Neogobius melanostomus (Pallas, 1814), Based on Laboratory Size Preference and Field Diet in Different Habitats in the Western Basin of Lake Erie
ABSTRACT:

The round goby, Neogobius melanostomus, is an invasive benthic fish species in the Laurentian Great Lakes that is threatening native fish populations through competition, predation, and trophic dynamic change. This study examined the trophic dynamic plasticity of round goby along a depth gradient based on laboratory and field observations to determine prey species consumed and mussel prey size selection. Prey size selection in the laboratory was assessed by presenting individual round goby with quagga mussels (Dreissena rostriformis bugensis) of various class sizes (i.e., 6.0–9.9 mm, 10.0–12.9 mm, 13.0–15.9 mm, and 16.0–18.9 mm in length). Round goby exhibited a selection preference for small sized quagga mussels, although in individual trial events, mussels were consumed from all four size classes. Prey species consumed from shallow and deep sites in the western basin of Lake Erie were assessed using individual gut contents to calculate measures of prey importance, diversity, and dominance. Based on the Index of Relative Importance (IRI), Cladocera was found to be the most consumed prey item for both males and females and between study sites. Both sexes consumed a variety of prey items although females exhibited greater prey dominance or reliance on one prey item. Round goby individuals at the shallow, natural shoreline site had the highest trophic diversity, while individuals at the deep site exhibited the highest prey dominance. Diet of round goby in the western basin of Lake Erie are mainly dominated by just a few prey items.

DOI: http://dx.doi.org/10.3391/ai.2015.10.4.09 VOLUME: 10 ISSUE: 4 LENGTH: 11 pages

Interactive Effects of Temperature, Nitrogen, and Zooplankton on Growth and Protein and Carbohydrate Content of Cyanobacteria from Western Lake Erie

OHSU-RS-1517
Interactive Effects of Temperature, Nitrogen, and Zooplankton on Growth and Protein and Carbohydrate Content of Cyanobacteria from Western Lake Erie
ABSTRACT:

Harmful algal blooms (HABs) in freshwater ecosystems, especially of cyanobacterial species, are becoming more frequent and expanding geographically, including in Lake Erie in North America. HABs are the result of complex and synergistic environmental factors, though N or P eutrophication is a leading cause. With global mean temperatures expected to increase an additional 2˚C – 5˚C by 2100, cyanobacterial blooms are predicted to increase even more, given their typically-high temperature optimum for growth. We investigated how increases in temperature and nitrogen, singly or in combination, affect the growth, food quality, and herbivory of Lake Erie cyanobacteria. Algal community samples collected from Lake Erie, and isolated non-N-fixing (Microcystis aeruginosa) and N-fixing (Anabaena flos-aquae) cyanobacterial species, were cultured at 20˚C, 25˚C, or 30˚C, and at 5, 50, 150, or 250 μM N, and then analyzed for growth and (for isolates) content of total protein and non-structural carbohydrates (NSC). Temperature and N both affected algal growth, and there were temperature × N interactions, which were sometimes affected by presence/absence of zooplankton. For example, cyanobacteria (but not green algae) growth increased with both temperature and N, especially from 25˚C to 30˚C, but N and herbivore presence increased cyanobacterial growth primarily only at 30˚C. In general, temperature and N had little consistent effect on NSC, but increasing temperature and N tended to increase protein content in Microcystis and Anabaena (temperature effects mostly at higher N levels). In Anabaena, increases in N did not increase growth or protein at 20˚C or 25˚C, but did increase both at 30˚C, indicating that N fixation.

Intra-andinter-seasonalvariabilityofnutrientsinatropical monsoonal estuary(Zuari,India)

OHSU-RS-1512
Intra-andinter-seasonalvariabilityofnutrientsinatropical monsoonal estuary(Zuari,India)

A study was conducted to understand the intra- and inter-seasonal variability of dissolved oxygen and nutrients in a tropical monsoon estuary (Zuari in Goa, India). We adopted a dual sampling approach with (a) daily or alternate day sampling at a fixed location in the mid-estuarine zone and (b) longitudinal transect sampling from freshwater end to mouth during spring and neap tides of each month for about a year. Multivariate statistical analyses of oxygen and nutrients were carried out to evaluate the hypotheses: (i) biogeochemical processes chiefly regulate their variability and (ii) anthropogenic inputs lead to material accumulation in the estuary. Multivariate statistical analyses helped identify the controlling factors of the oxygen and nutrient variability. Our results significantly revealed (i) physical forcings (freshwater discharge and tidal circulation, these also facilitate sedimentary releases) are more important than biogeochemical processes in determining oxygen and nutrient variability in the water column and (ii) the monsoon driven regular annual flushing makes the system resilient to human interference as the Zuari estuary returns to normalcy by postmonsoon every year. Our study identified the significance of subsurface discharges in transporting mining effluents from the river basin. Results also suggest that extrapolation of controlling factors of biogeochemical variables at a fixed location to the entire estuary is untenable since the relative dominance of forcings vary in time and space in the estuary.

ABSTRACT:

A study was conducted to understand the intra- and inter-seasonal variability of dissolved oxygen and nutrients in a tropical monsoon estuary (Zuari in Goa, India). We adopted a dual sampling approach with (a) daily or alternate day sampling at a fixed location in the mid-estuarine zone and (b) longitudinal transect sampling from freshwater end to mouth during spring and neap tides of each month for about a year. Multivariate statistical analyses of oxygen and nutrients were carried out to evaluate the hypotheses: (i) biogeochemical processes chiefly regulate their variability and (ii) anthropogenic inputs lead to material accumulation in the estuary. Multivariate statistical analyses helped identify the controlling factors of the oxygen and nutrient variability. Our results significantly revealed (i) physical forcings (freshwater discharge and tidal circulation, these also facilitate sedimentary releases) are more important than biogeochemical processes in determining oxygen and nutrient variability in the water column and (ii) the monsoon driven regular annual flushing makes the system resilient to human interference as the Zuari estuary returns to normalcy by postmonsoon every year. Our study identified the significance of subsurface discharges in transporting mining effluents from the river basin. Results also suggest that extrapolation of controlling factors of biogeochemical variables at a fixed location to the entire estuary is untenable since the relative dominance of forcings vary in time and space in the estuary.

DOI: 10.1016/j.csr.2014.04.005 VOLUME: 82

A population genetic window into the past and future of the walleye Sander vitreus: relation to historic walleye and the extinct “blue pike” S. v. “glaucus”

OHSU-RS-1511
A population genetic window into the past and future of the walleye Sander vitreus: relation to historic walleye and the extinct “blue pike” S. v. “glaucus”
ABSTRACT:

Conserving genetic diversity and local adaptations are management priorities for wild populations of exploited species, which increasingly are subject to climate change, habitat loss, and pollution. These constitute growing concerns for the walleye Sander vitreus, an ecologically and economically valuable North American temperate fish with large Laurentian Great Lakes’ fisheries. This study compares genetic diversity and divergence patterns across its widespread native range using mitochondrial (mt) DNA control region sequences and nine nuclear DNA microsatellite (μsat) loci, examining historic and contemporary influences. We analyze the genetic and morphological characters of a putative endemic variant– “blue pike” S. v. “glaucus” –described from Lakes Erie and Ontario, which became extinct. Walleye with turquoise-colored mucus also are evaluated, since some have questioned whether these are related to the “blue pike”.

DOI: 10.1186/1471-2148-14-133 VOLUME: 14 ISSUE: 133

Application of empirical and semi-analytical algorithms to MERIS data for estimating chlorophyll a in Case 2 waters of Lake Erie

OHSU-RS-509
Application of empirical and semi-analytical algorithms to MERIS data for estimating chlorophyll a in Case 2 waters of Lake Erie
LENGTH: 12 pages

Sonochemical degradation of cipro?oxacin and ibuprofen in the presence of matrix organic compounds

OHSU-RS-496
Sonochemical degradation of cipro?oxacin and ibuprofen in the presence of matrix organic compounds
LENGTH: 8 pages

Physiological stress response of yellow perch subjected to repeated handlings and salt treatments at different temperatures

OHSU-RS-505
Physiological stress response of yellow perch subjected to repeated handlings and salt treatments at different temperatures
LENGTH: 6 pages

Nitrogen constrains the growth of late summer cyanobacterial blooms in Lake Erie

OHSU-RS-508
Nitrogen constrains the growth of late summer cyanobacterial blooms in Lake Erie
LENGTH: 11 pages

Nutrient inputs to the Laurentian Great Lakes by source and watershed estimated using SPARROW watershed Models' by Dale M. Robertson and David A. Saad 'Nutrient Inputs to the Laurentian Great Lakes by source and watershed

OHSU-RS-495
Nutrient inputs to the Laurentian Great Lakes by source and watershed estimated using SPARROW watershed Models' by Dale M. Robertson and David A. Saad 'Nutrient Inputs to the Laurentian Great Lakes by source and watershed
LENGTH: 10 pages

Development of a vector-based method for coastal bluffline mapping using LiDAR data and a comparison study in the area of Lake Erie

OHSU-RS-506
Development of a vector-based method for coastal bluffline mapping using LiDAR data and a comparison study in the area of Lake Erie
LENGTH: 18 pages

A Novel method for tracking western Lake Erie Microcystis blooms, 2002-2011

OHSU-RS-491
A Novel method for tracking western Lake Erie Microcystis blooms, 2002-2011
LENGTH: 6 pages

A new Start-PCR approach to detect and quantify fish Viral Hemorrhagic Septicemia virus (VHSv): Enhanced quality control with internal standards

OHSU-RS-483
A new Start-PCR approach to detect and quantify fish Viral Hemorrhagic Septicemia virus (VHSv): Enhanced quality control with internal standards
LENGTH: 14 pages

Multivariate approach to estimate color producing agents in Case 2 waters using-first-derivative spectrophotometer data

OHSU-RS-482
Multivariate approach to estimate color producing agents in Case 2 waters using-first-derivative spectrophotometer data
LENGTH: 26 pages

Diversity and distribution of free-living and particle-associated bacterioplankton in Sandusky Bay and adjacent waters of Lake Erie Western Basin

OHSU-RS-492
Diversity and distribution of free-living and particle-associated bacterioplankton in Sandusky Bay and adjacent waters of Lake Erie Western Basin
LENGTH: 6 pages

Using pulsed wave ultrasound to evaluate the suitability of hydroxyl radical scavengers in sonochemical systems

OHSU-RS-497
Using pulsed wave ultrasound to evaluate the suitability of hydroxyl radical scavengers in sonochemical systems
LENGTH: 7 pages

Factors influencing pharmaceutical and personal care product degradation in aqueous solution using pulsed wave ultrasound

OHSU-RS-503
Factors influencing pharmaceutical and personal care product degradation in aqueous solution using pulsed wave ultrasound
LENGTH: 8 pages

Accurate detection and quantification of the fish Viral Hemorrhagic Septicemia virus (VHSv) with a two-color fluorometric real-time PCR assay

OHSU-RS-504
Accurate detection and quantification of the fish Viral Hemorrhagic Septicemia virus (VHSv) with a two-color fluorometric real-time PCR assay
LENGTH: 12 pages

Evaluating multiple color-producing agents in Case II waters from Lake Erie

OHSU-RS-502
Evaluating multiple color-producing agents in Case II waters from Lake Erie
LENGTH: 27 pages

Genetic and morphometric differences demonstrate fine-scale population substructure of the yellow perch Perca flavescens: need for redefined management units

OHSU-RS-499
Genetic and morphometric differences demonstrate fine-scale population substructure of the yellow perch Perca flavescens: need for redefined management units
LENGTH: 16 pages

Effects of shear on initial bacterial attachment in slow flowing systems

OHSU-RS-500
Effects of shear on initial bacterial attachment in slow flowing systems
LENGTH: 8 pages

Ohio’s 2010 Lake Erie charter fishing industry

OHSU-RS-469
Ohio’s 2010 Lake Erie charter fishing industry
LENGTH: 10 pages

Role of suspended sediments and mixing in reducing photoinhibition in the bloom-forming Cyanobacterium Microcystis

OHSU-RS-479
Role of suspended sediments and mixing in reducing photoinhibition in the bloom-forming Cyanobacterium Microcystis
LENGTH: 13 pages

Within-stream release-site fidelity of steelhead trout from Lake Erie hatchery stocks

OHSU-RS-507
Within-stream release-site fidelity of steelhead trout from Lake Erie hatchery stocks
LENGTH: 9 pages

Evolution and biogeography of an emerging quasispecies: Diversity patterns of the fish Viral Hemorrhagic Septicemia virus

OHSU-RS-461
Evolution and biogeography of an emerging quasispecies: Diversity patterns of the fish Viral Hemorrhagic Septicemia virus
LENGTH: 15 pages

A Case for amenity-driven growth? Estimating heterogeneous household demands for lake amenities and industrial disamenities in the Great Lakes region

OHSU-RS-485
A Case for amenity-driven growth? Estimating heterogeneous household demands for lake amenities and industrial disamenities in the Great Lakes region
LENGTH: 24 pages

Plasticity of total and intracellular phosphorus quotas in Microcystis aeruginosa cultures and Lake Erie algal assemblages

OHSU-RS-457
Plasticity of total and intracellular phosphorus quotas in Microcystis aeruginosa cultures and Lake Erie algal assemblages
LENGTH: 9 pages

Effect of rhamnolipids on initial attachment of bacteria on glass and octadecyltrichlorosilane-modified glass

OHSU-RS-473
Effect of rhamnolipids on initial attachment of bacteria on glass and octadecyltrichlorosilane-modified glass
LENGTH: 8 pages

Evaluation of one-stage and two-stage selection in yellow perch I: Genetic and phenotypic parameters for growth traits of F1fish reared in ponds using microsatellite parentage assignment

OHSU-RS-484
Evaluation of one-stage and two-stage selection in yellow perch I: Genetic and phenotypic parameters for growth traits of F1fish reared in ponds using microsatellite parentage assignment
LENGTH: 10 pages

Seasonal Si:C ratios in Lake Erie diatoms - Evidence of an active winter diatom community

OHSU-RS-489
Seasonal Si:C ratios in Lake Erie diatoms - Evidence of an active winter diatom community
LENGTH: 6 pages

Great Lakes climate change curriculum

OHSU-RS-487
Great Lakes climate change curriculum
LENGTH: 13 pages

Evaluation of the natural product antifoulant, zosteric acid, for preventing the attachment of quagga mussels: a preliminary study

OHSU-RS-450
Evaluation of the natural product antifoulant, zosteric acid, for preventing the attachment of quagga mussels: a preliminary study
LENGTH: 4 pages

Temporal and spatial genetic consistency of walleye spawning groups

OHSU-RS-470
Temporal and spatial genetic consistency of walleye spawning groups
LENGTH: 13 pages

ADMESH: An advanced, automatic unstructured mesh generator for shallow water models

OHSU-RS-471
ADMESH: An advanced, automatic unstructured mesh generator for shallow water models
LENGTH: 15 pages

A Systematic approach detection of seagrass patches from hyperspectral imagery

OHSU-RS-474
A Systematic approach detection of seagrass patches from hyperspectral imagery
LENGTH: 16 pages

Database of research in marine and aquatic education

OHSU-RS-488
Database of research in marine and aquatic education
LENGTH: 4 pages

A Case for amenity-driven growth? Impacts of lake amenities on population, employment and housing markets in the Great Lakes region

OHSU-RS-486
A Case for amenity-driven growth? Impacts of lake amenities on population, employment and housing markets in the Great Lakes region
LENGTH: 20 pages
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