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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.


Microcystis Rising: Why Phosphorus Reduction Isn’t Enough to Stop CyanoHABs

DOI: 10.1289 VOLUME: 125 ISSUE: 2 LENGTH: 5 pages

A Comparison of Water Sampling and Analytical Methods in Western Lake Erie


Leptodora kindtii Population Dynamics in the Island Region of Western Lake Erie Before and After the Invasion of the Predacious Cladoceran Bythotrephes Longimanus


Competition among native and non-native species can cause decreases in population size and production of both species. The native predaceous crustacean zooplankter Leptodora kindtii shares a similar niche with the invasive Bythotrephes longimanus in Lake Erie. This niche overlap may contribute to the decline in abundance, and production of L. kindtii in the Western Basin of Lake Erie. Historical (1946) and recent (2006) data were used to determine if the decline in L. kindtii abundance and production was associated with the effects of B. longimanus, which invaded Lake Erie in the mid-1980’s. Pre-invasion abundances and lengths of L. kindtii were compared with current data (2006). A change in prey community abundance, composition and dynamics were observed, relative to pre-invasion, with a marked decline in abundance and size of L. kindtii after the invasion of B. longimanus. Competition for food and direct predation are two explanations, among others, for the declines observed in L. kindtii size, abundance and production that have occurred since B. longimanus invasion.

VOLUME: 116 ISSUE: 2 LENGTH: 7 pages

Two Decades of Genetic Consistency in a Reproductive Population in the Face of Exploitation: Patterns of Adult and Larval Walleye (Sander vitreus) From Lake Erie’s Maumee River


Analyses of genetic variability and allelic composition in a species exhibiting reproductive fidelity to natal sites may provide important ecological indication of temporal population dynamics, facilitating understanding responses to past disturbances and future climate change. The walleye is an ecologically and economically valuable species, whose largest fishery centers in Lake Erie of the Laurentian Great Lakes; it exhibits reproductive site fidelity, despite otherwise wide-ranging dispersal. We tested whether genetic composition and diversity have remained temporally stable in Lake Erie’s Maumee River, which is the largest and most highly fished spawning run. This population has experienced over a century of exploitation, habitat alterations, and pollution, which may have affected genetic structure and might influence future sustainability. Fourteen nuclear DNA microsatellite loci were analyzed from 744 spawning run walleye to test genetic patterns across: (1) years (N = 12, spanning 1995–2013), (2) birth year cohorts, (3) the sexes, (4) those reproducing earlier (ages 2–6) versus later (7 or older) in life, and (5) the adults versus larvae. Results indicated stability in genetic diversity levels (mean HO = 0.76 ± 0.03) and allelic composition across years (FST = 0.000–0.006, NS), cohorts (FST = 0.000–0.013, NS), sexes (FST = 0.000, NS), earlier versus later reproduction (FST = 0.000, NS), and between the larvae and adults (FST = 0.000–0.004, NS). Number of breeders and effective population size were substantial and consistent. This reproductive population thus has maintained genetic stability and high diversity, despite intensive anthropogenic pressures.


Combining COMSOL Modeling with Acoustic Pressure Maps to Design Sono-Reactors


Scaled-up and economically viable sonochemical systems are critical for increased use of ultrasound in environmental and chemical processing applications. In this study, computational simulations and acoustic
pressure maps were used to design a larger-scale sono-reactor containing a multi-stepped ultrasonic horn. Simulations in COMSOL Multiphysics showed ultrasonic waves emitted from the horn neck and tip, generating multiple regions of high acoustic pressure. The volume of these regions surrounding the horn neck were larger compared with those below the horn tip. The simulated acoustic field was verified by acoustic pressure contour maps generated from hydrophone measurements in a plexiglass box filled with water. These acoustic pressure contour maps revealed an asymmetric and discrete distribution of acoustic pressure due to acoustic cavitation, wave interaction, and water movement by ultrasonic irradiation.

The acoustic pressure contour maps were consistent with simulation results in terms of the effective scale of cavitation zones (10 cm and <5 cm above and below horn tip, respectively). With the mapped acoustic field and identified cavitation location, a cylindrically-shaped sono-reactor with a conical bottom was designed to evaluate the treatment capacity (5 L) for the multi-stepped horn using COMSOL simulations. In this study, verification of simulation results with experiments demonstrates that coupling of COMSOL simulations with hydrophone measurements is a simple, effective and reliable scientific method to evaluate reactor designs of ultrasonic systems.

DOI: 10.1016/j.ultsonch.2016.01.036 VOLUME: 31 LENGTH: 8 pages

Quantifying Emissions of Methane Derived From Anaerobic Organic Matter Respiration and Natural Gas Extraction in Lake Erie


Despite a growing awareness of the importance of inland waters in regional and global carbon © cycles, particularly as sources of the greenhouse gases carbon dioxide (CO2) and methane (CH4), very little is known about C sources and fluxes in the Laurentian Great Lakes, Earth’s largest surface freshwater system. Here, we present a study of CH4 dynamics in Lake Erie, which has large spring algae blooms linked to fertilizer runoff and followed by hypoxia, as well as an extensive network of natural gas wells and pipelines in Canadian waters. Lake Erie is a positive source of CH4 to the atmosphere in late summer, even in shallow regions without water column hypoxia. Stable isotopic measurements indicate that both biogenic and thermogenic CH4 contribute to emissions from Lake Erie. We estimate that Lake Erie emits 1.360.6 3 105 kg CH4-C d21 in late summer, with approximately 30% of CH4 derived from natural gas infrastructure. Additional work is needed to determine the spatial and temporal dynamics of CH4 emissions from Lake Erie and to confirm estimates of source contribution. Studies of the C cycle in large lakes are not as straightforward as those in smaller lakes, as, in addition to O2 availability, subsurface currents and high winds may exert significant control over dissolved CH4 patterns. If climate warming and increasing precipitation intensity lead to increased algal biomass and/or greater extent and duration of hypoxia, this may increase emissions of CH4 from Lake Erie in a positive feedback to climate change.

DOI: 10.1002/lno.10273 LENGTH: 10 pages

Nutrient-Controlled Niche Differentiation of Western Lake Erie Cyanobacterial Populations Revealed via Metatranscriptomic Surveys


Although toxic cyanobacterial blooms in western Lake Erie threaten drinking water supplies and are promoted by nutrient loading, the precise nutrient regime that selects specific cyanobacteria populations is poorly understood. Here, we assess shifts in cyanobacterial abundances and global gene-expression patterns in response to natural and manipulated gradients in nitrogen and phosphorus to identify gene pathways that facilitate dominance by different cyanobacteria. Gradients in soluble reactive phosphorus shaped cyanobacterial communities and elicited the largest transcriptomic responses. Under high-P conditions (closest to the mouth of the Maumee River), Anabaena and Planktothrix were the dominant cyanobacterial populations, and experimental P and ammonium enrichment promoted nitrogen fixation gene (nifH) expression in Anabaena. For Microcystis, experimental additions of P up-regulated genes involved in phage defense, genomic rearrangement, and nitrogen acquisition but led to lower abundances. Within offshore, low-P regions of the western basin of Lake Erie, Microcystis up-regulated genes associated with P scavenging (pstSCAB, phoX) and dominated cyanobacterial communities. Experimental additions of ammonium and urea did not alter Microcystis abundances but did up-regulate protease inhibitors (aer and mcn gene sets) and microcystin synthetase genes (mcy), with urea enrichment yielding significant increases in microcystin concentrations. Our findings suggest that management plans that reduce P loads alone may not significantly reduce the risk of cyanobacterial blooms in western Lake Erie but rather may promote a shift among cyanobacterial populations (Microcystis, Anabaena, and Planktothrix) toward a greater dominance by toxic strains of Microcystis.

DOI: 10.1021/acs.est.5b03931 VOLUME: 50 ISSUE: 2 LENGTH: 11 pages

Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size

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

Quantifying and Reducing Uncertainty in Estimated Microcystin Concentrations from the ELISA Method

DOI: 10.1021/acs.est.5b03029 VOLUME: 49

Designing and Characterizing a Multi-Stepped Ultrasonic Horn for Enhanced Sonochemical Performance


The commonly used ultrasonic horn generates localized cavitation below its converging tip resulting in a dense bubble cloud near the tip and limiting diffusion of reactive components into the bubble cloud or reactive radicals out of the bubble cloud. To improve contact between reactive components, a novel ultrasonic horn design was developed based on the principles of the dynamic wave equation. The horn, driven at 20 kHz, has a multi-stepped design with a cone-shaped tip increasing the energy-emitting surface areas and creating multiple reactive zones. Through different physical and chemical experiments, performance of the horn was compared to a typical horn driven at 20 kHz. Hydrophone measurements showed high acoustic pressure areas around the horn neck and tip. Sonochemiluminescence experiments verified multiple cavitation zones consistent with hydrophone readings. Calorimetry and dosimetry results demonstrated a higher energy efficiency (31.3%) and a larger hydroxyl radical formation rate constant (0.36 μM min−1) compared to typical horns. In addition, the new horn degraded naphthalene faster than the typical horn tested. The characterization results demonstrate that the multi-stepped horn configuration has the potential to improve the performance of ultrasound as an advanced oxidation technology by increasing the cavitation zone in the solution.

DOI: 10.1016/j.ultsonch.2015.05.013 VOLUME: 27 LENGTH: 8 pages

Short Winters Threaten Temperate Fish Populations


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

Effects of Increasing Nitrogen and Phosphorus Concentrations on Phytoplankton Community Growth and Toxicity During Planktothrix Blooms in Sandusky Bay, Lake Erie


Sandusky Bay experiences annual toxic cyanobacterial blooms dominated by Planktothrix agardhii/suspensa. To further understand the environmental drivers of these events, we evaluated changes in the growth response and toxicity of the Planktothrix-dominated blooms to nutrient amendments with orthophosphate (PO4) and inorganic and organic forms of dissolved nitrogen (N; ammonium (NH4), nitrate (NO3) and urea) over the bloom season (June − October). We complemented these with a metagenomic analysis of the planktonic microbial community. Our results showed that
bloom growth and microcystin (MC) concentrations responded more frequently to additions of dissolved N than PO4, and that the dual addition of NH4 + PO4 and Urea + PO4 yielded the highest MC concentrations in 54% of experiments. Metagenomic analysis confirmed that P. agardhii/suspensa was
the primary MC producer. The phylogenetic distribution of nifH revealed that both heterocystous cyanobacteria and heterotrophic proteobacteria had the genetic potential for N2 fixation in Sandusky Bay. These results suggest that as best management practices are developed for P reductions in Sandusky Bay, managers must be aware of the negative implications of not managing N loading into this system as N may significantly impact cyanobacterial bloom size and toxicity.

DOI: 10.1021/acs.est.5b00799 VOLUME: 49 LENGTH: 10 pages

The Great Lakes Charter Fishing Industry: 2002 to 2011

DOI: 10.1080/03632415.2015.1029574 VOLUME: 40 ISSUE: 5

An examination of sources of sensitivity of consumer surplus estimates in travel cost models


We examine sensitivity of estimates of recreation demand using the Travel Cost Method (TCM) to four factors. Three of the four have been routinely and widely discussed in the TCM literature: a) Poisson verses negative binomial regression; b) application of Englin correction to account for endogenous
stratification; c) truncation of the data set to eliminate outliers. A fourth issue we address has not been widely modeled: the potential effect on recreation demand of the interaction between income and travel cost. We provide a straightforward comparison of all four factors, analyzing the impact of each on regression parameters and consumer surplus estimates. Truncation has a modest effect on estimates
obtained from the Poisson models but a radical effect on the estimates obtained by way of the negative binomial. Inclusion of an income-travel cost interaction term generally produces a more conservative but not a statistically significantly different estimate of consumer surplus in both Poisson and negative binomial models. It also generates broader confidence intervals. Application of truncation, the Englin
correction and the income-travel cost interaction produced the most conservative estimates of consumer surplus and eliminated the statistical difference between the Poisson and the negative binomial. Use of the income-travel cost interaction term reveals that for visitors who face relatively low travel costs, the relationship between income and travel demand is negative, while it is positive for those who face high travel costs. This provides an explanation of the ambiguities on the findings regarding the role of income
widely observed in the TCM literature. Our results suggest that policies that reduce access to publicly owned resources inordinately impact local low income recreationists and are contrary to environmental justice.


Length-weight Relationships of the Emerald Shiner (Notropis atherinoides - Rafinesque, 1818) in the Western Basin of Lake Erie

DOI: na ISBN: na VOLUME: 114 ISSUE: 2 LENGTH: 9 pages

Age and Growth of Round Goby Neogobius Melanostomus Associated with Depth and Habitat in the Western Basin of Lake Erie


Poor condition may indicate that the Lake Erie population has reached saturation or may reflect indirect fitness costs associated with increasing anoxic or hypoxic hypolimnion conditions.


Round goby Neogobius melanostomus were examined from the Bass Islands area in the western basin of Lake Erie, U.S.A., to determine age and growth correlations. A total of 188 specimens were collected and examined during summer 2011 with 90 aged using scale analysis. Fish were grouped by sex, depth of habitat and habitat type (anthropogenically modified shallows, natural shallows and open lake deep water). Fish ranged from 17 to 117 mm total length (LT ) and 0+ to 3+ years. Males dominated the population (1·94:1) and backcalculated age showed that both sexes grew exponentially, with male growth rate increasing faster than female. Males were significantly larger than females in LT and mass (both P < 0·001). The relative mass index (Wr ) was low for the sampled population (mean ± s.d. = 32·00 ± 26·87 g), implying that the health of the Bass Island area population is very poor when compared with the species throughout its range. This could be due to a lack of food resources related to population size or that the fish is not optimally utilizing the available food resources. In contradiction to these findings, regression slope coefficient (b), calculated using Fulton’s condition factor (K) (mean ± s.d. =1·50 ± 0·20), was very low for each habitat, implying a healthy population throughout. This seemingly opposite effect may be due to more individuals per unit area in shallow waters, which would cause increased competition for resources. Poor condition may indicate that the Lake Erie population has reached saturation or may reflect indirect fitness costs associated with increasing anoxic or hypoxic hypolimnion conditions.

DOI: 10.1111/jfb.12576 VOLUME: 86 ISSUE: 2 LENGTH: 16 pages

Temporal Population Genetic Structure of Yellow Perch Spawning Groups in the Lower Great Lakes


This study tested the hypothesis that the genetic composition of Yellow Perch Perca flavescens spawning groups at specific sites remained consistent among years or age-cohorts; this likely would influence spatial population structure and be important for delineating management units. Previous studies identified that spawning groups genetically differed among locations across fine geographic scales, but it was unknown whether these patterns persisted from year to year. We analyzed 15 nuclear DNA microsatellite loci from Yellow Perch spawning at six Lake Erie locations in 2009 in reference to two out-groups spawning in Lakes St. Clair and Ontario. Results were compared with a prior study of samples from the same locations that had been collected in various years, ranging from 2001 to 2005. We evaluated consistency for two of the spawning groups across multiple birth-year-cohorts. Results indicated that the levels of genetic diversity were similar across all spawning groups and years. All eight spawning groups genetically differed from one other, with their allelic compositions varying between the two sampling periods. Some variation occurred among individual sampling years and birth-cohorts, with the 2003 cohort being the most distinctive. Sampling groups contained relatively high proportions of full siblings (mean = 18.5%, ranging to 75% for the 2001 birth-cohort spawning at the eastern Lake Erie site), yet inbreeding appeared relatively low. Differences at sampling sites over time did not appear to reflect genetic drift but may instead suggest that spawning groups reproduce in slightly different locations from year to year or perhaps within a given season; this merits examination. Spatial and temporal patterns may reflect kin-group structuring and differential reproductive success, in which strong year-classes dominate spawning groups and impact genetic structure.

DOI: 10.1080/00028487.2014.982260 VOLUME: 144 ISSUE: 1

Efficacy of formalin, iodine and sodium chloride in improvement of egg hatching rate and fry survival prior to the onset of exogenous feeding in yellow perch

DOI: 10.1111/are.12694 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

VOLUME: 10 ISSUE: 4 LENGTH: 11 pages

Occupancy, Activity, and Relationships to Watershed Factors in Predicting Burrowfidelity in the Digger Crayfish Fallicambarus Fodiens (Cottle, 1863)


An intensive single season pilot study was conducted with the digger crayfish, Fallicambarus fodiens (Cottle, 1863) to evaluate relationships between burrow and wetland attributes. Factor Analysis identified significant factors correlated with burrow placement, individual presence, type and frequency of activity. Factor 1 explained 36.89% of the variance associated with hydric type, percent soil moisture, fine substrate grain sizes, and habitat condition, while factor 2 explained 14.78% of the variance based on large grain particle sizes. A significant difference was observed in crayfish inhabitant activity with trap status, burrow state, and presence of activity. Four specific types of activities were related to distance to above groundwater including the trap being pulled into the burrow, the burying of the trap into a burrow cap, a capped burrow established beneath the trap, and relationship with standing water. Based on 12.5% individual recapture, 100% were present in the original burrow of capture.

DOI: 10.1163/1937240X-00002320 VOLUME: 35 ISSUE: 2 LENGTH: 8 pages

Evolutionary Relationships, Population Genetics, and Ecological and Genomic Adaptations of Perch (Perca)


The latest results about the evolutionary, biogeographic, and population genetic relationships of the three species comprising the percid fish genus Perca are presented, explained, and discussed. New analyses from new data dated the origin of the genus to an estimated 19.8 million years ago (mya) during the early Miocene Epoch, and the distribution of ancestral Perca likely extended across the North Atlantic Land Bridge until the mid-Miocene. The earliest evolutionary bifurcation led to the diversifi cation of the European perch P. fl uviatilis from the lineage shared by the common ancestor of the North American yellow perch P. fl avescens and the Eurasian Balkash perch P. schrenkii. The latter two species diverged during the later Miocene, after the Land Bridge was closed. The European and yellow perches are both widely distributed across their respective continents, with biogeographic areas housing high genetic distinctiveness. Population genetic structure in their northern regions were shaped by post-glacial colonization patterns from multiple refugia, whose admixture increased diversity. Today’s spawning groups are modest in genetic diversity yet very divergent from one another, which may reflect an apparent tendency of perch to live with relatives throughout their lives. There is a disconnect between the genetic divisions among populations and the delineation of fishery management units in the yellow perch, which is of concern. Employing a combined fisheries management and genetics/genomic approach will provide further understanding to help maintain the genetic diversity and unique adaptations of perch populations in the face of increasing anthropogenic influences, including climate change.

LENGTH: 39 pages

A Comprehensive Approach to Evaluating Watershed Models for Predicting River Flow Regimes Critical to Downstream Ecosystem Services


Diet Shift Response in Round Goby, Neogobius melanostomus, Based on Size, Sex, Depth and Habitat in the Western Basin of Lake Erie

VOLUME: 30 ISSUE: 5 LENGTH: 7 pages

Summer phytoplankton nutrient limitation in Maumee Bay of Lake Erie during high-flow and low-flow years


Manuscript comparing Maumee Bay phytoplankton growth from 2010-2012


Algal production inMaumee Bay in western Lake Erie is highly affected by inputs of nitrogen (N) and phosphorus (P) from the Maumee River, which drains predominantly agricultural lands, leading to the formation of cyanobacterial blooms. In a 3-year study, precipitation and discharge ranged from relatively low (2012) to relatively high (2011) with corresponding changes in the size of the cyanobacterial bloom. This study aimed to quantify the relation between river discharge and algal nutrient limitation in Maumee Bay. During the summer growing seasons, 20 nutrient enrichment bioassays were performed to determine which nutrient (P or N) might limit phytoplankton growth; and ambient N and P concentrations were monitored. The bioassays suggested that phytoplankton growth shifted from P-limited to N-limited during summer of the low and intermediate discharge years (2012 and 2010, respectively), whereas during the high discharge year (2011) phytoplankton were nutrient-replete before becoming N-limited. Phosphorus-replete growth during the high discharge year likely was due to high P loads from the river and dissolved P concentrations greater than 1 μmol/L. Symptoms of N-limited growth occurred during August and September in all three years and during July of 2012 when NO3 − plus NH4 + concentration was less than 7.29 μmol/L suggesting lowor no correspondence between N-limitation and size of the cyanobacterial bloom. Occurrence of a relatively small cyanobacterial bloom in 2012 following the record-breaking bloom in 2011 suggests the possibility of fast-reversal of eutrophication in Maumee Bay if P loading from the watershed could be decreased.

DOI: 10.1016/j.jglr.2014.04.009 VOLUME: 40 ISSUE: 3 LENGTH: 7 pages

Connecting the blooms: tracking and establishing the origin of the record-breaking Lake Erie Microcystis bloom of 2011 using DGGE


Summer blooms of Microcystis now occur every year in Lake Erie with varying concentration, duration, and spatial extent. The recording-breaking bloom of 2011 began in the western corner of the lake during early summer, and reached its peak in late summer covering 2968 km2. Start and peak blooms were offset by 3 mo and separated by 120 km, raising the question: Is Microcystis transported across the lake or do separate blooms arise from separate source populations? This study addressed this question by measuring the genetic diversity of Microcystis across the lake and throughout the summer. Seven sites separated by about 100 km were sampled monthly during the summer of 2011 for genetic analysis of the Microcystis population. Furthermore, 2 major rivers (Maumee and Sandusky) and lake sediments were sampled and collected prior to bloom formation to investigate source populations. Denaturing gradient gel electrophoresis was used to generate Microcystis-specific molecular fingerprints of the 16S-23S rRNA internal transcribed spacer region. Dendrograms and principal component analysis were used to investigate similarity among samples. Fingerprints of lake water samples were more similar to the sediments than tributaries, indicating the sediments were a more likely bloom source. All lakes samples collected were > 50% similar with several universal bands, indicating Microcystis was transported west to east by water currents and that the beginning and peak blooms were not isolated.

This information characterizes the origin and movement of this massive and problematic bloom, and can be used to inform management practices aimed at preventing blooms in Lake Erie.

DOI: 10.3354/ame01708 VOLUME: 73 ISSUE: 73

Massive outbreaks of Noctiluca scintillans blooms in the Arabian Sea due to spread of hypoxia


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


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.


Genetic History of Walleyes Spawning in Lake Erie's Cattaraugus Creek: a Comparison of Pre- and Poststocking


Fish stocking (artificial supplementation) has been used to augment populations and angling opportunities. However, genetic composition and adaptations of native fish populations may be affected, raising management concerns. From 1995 to 2000, the New York State Department of Environmental Conservation stocked Walleye Sander vitreus fry and fingerlings from the Maumee River (western Lake Erie) into Cattaraugus Creek (eastern Lake Erie). We analyzed nuclear microsatellite (sat) DNA and mitochondrial DNA (mtDNA) variation in Cattaraugus Creek Walleyes for comparisons between prestocking and poststocking groups, among annual spawning runs (1998–2011), among age cohorts, and between sexes. Results for genetic differentiation (index FST) were not significant between prestocking and poststocking groups (sat: FST = 0.003; mtDNA: FST < 0.001), and the two groups did not resemble stocked Maumee River fingerlings (sat: FST = 0.003–0.012; mtDNA: FST = 0.076–0.090). Tests for differentiation were not significant among annual spawning runs (sat: FST = <0.001–0.007; mtDNA: FST = <0.001–0.049), among age cohorts (sat: FST = <0.001–0.006; mtDNA: FST = <0.001–0.097), or between sexes (sat: FST < 0.001; mtDNA: FST < 0.001). Genetic diversity levels were high and consistent (sat: observed heterozygosity [mean ± SE] = 0.71 ± 0.04; mtDNA: haplotype diversity = 0.79 ± 0.01). Thus, despite stocking, the genetic signature of the native spawning run remained distinctive. However, the genetic composition of the local wild population and the stocking source should be assessed prior to any future supplementation plans.

DOI: 10.1080/00028487.2014.935477 VOLUME: 143 ISSUE: 5 LENGTH: 12 pages

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.

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”

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

Submersion Tolerance in a Lakeshore Population of Pardosa lapidicina (Araneae: Lycosidae)

DOI: 10.1636/B13-44.1 VOLUME: 42 ISSUE: 2

Oxygen use by Nitrification in the Hypolimnion and Sediments of Lake Erie


Nitrification is an oxygen consumptive process, consuming 2 mol of oxygen permol of ammonium oxidized. Hypolimnion
and sediment sampleswere collected during the summers of 2008–2010 in Lake Erie to determine the
total oxygen consumption and oxygen consumption fromnitrification by blocking nitrification with selective inhibitors.
Oxygen consumption by nitrification in the hypolimnion was 3.7 ± 2.9 (mean ± 1 SD) μmol O2/L/d,
with nitrification accounting for 32.6 ± 22.1% of the total oxygen consumption. Nitrification in the hypolimnion
contributed more to oxygen consumption in the eastern sites than western sites and was lowest in September.
The nitrification rate did not correlatewith environmental factors such as oxygen, nitrate or ammonium, or nitrifier
numbers. Oxygen consumption by nitrification in sediment slurries was 7.1 ± 5.8 μmol O2/g/d, with nitrification
accounting for 27.0 ± 19.2% of the total oxygen consumption with the lowest rates in July and the lowest
percentages in June. Oxygen consumption by nitrification in intact sediment coreswas 682 ± 61.1 μmol O2/m/d
with nitrification accounting for 30.4 ± 10.7% of the total oxygen consumption. Nitrification rates in intact cores
were generally highest in September. The proportion of oxygen consumed by nitrification corresponds closely
with what would be predicted from complete oxidation of a Redfield molecule (23%).While nitrification is unlikely
to be the dominant oxygen consumptive process, the rates observed in Lake Eriewere sufficient to theoretically
deplete a large portion of the hypolimnetic oxygen pool during the stratified period.

VOLUME: 40 ISSUE: 1 LENGTH: 5 pages

Organic and inorganic nitrogen utilization by nitrogen-stressed cyanobacteria during bloom conditions


Manuscript on nitrogen utilization by cyanobacteria


Cyanobacterial blooms often occur in lakes that have high phosphorus (P) and low nitrogen (N) concentrations, and the growth rate of the blooms is often constrained by N. For these reasons, many researchers have suggested that regulation of both P and N is required to control eutrophication. However, because N occurs in many bioavailable forms, regulation of a particular form may be beneficial rather than regulation of all N forms. To address how N-stressed cyanobacteria respond to various N inputs, N enrichment experiments (nitrate, ammonium, urea, and alanine) were performed during N-limited cyanobacterial blooms in Maumee and Sandusky Bays of Lake Erie and in Grand Lake St. Marys (GLSM). Bioavailable N (nitrate, urea, and ammonium) concentrationswere also determined. Microcystis aeruginosa dominated the Maumee Bay bloom, where the highest growth rates were in response to ammonium additions, and lowest growth rates were in response to nitrate. Urea and the amino acid alanine resulted in intermediate growth rates. Planktothrix agardhii dominated the Sandusky Bay and GLSM blooms, where nitrate, ammonium, and urea addition resulted in similar growth rates. Additions of alanine did not stimulate growth of the Planktothrix blooms. Incubations using stable isotope 15N showed the cyanobacteria had a preference for ammonium, but the other forms were also assimilated in the presence of ammonium. These results show that cyanobacterial blooms will assimilate multiple forms of N to support growth. Thus, if lake managers do decide that N abatement is necessary, then all forms of bioavailable N need to be constrained.

DOI: 10.1007/s10811-013-0118-0 VOLUME: 26 ISSUE: 1 LENGTH: 10 pages

Genetic connectivity and diversity of walleye (Sander vitreus) spawning groups in the Huron-Erie Corridor

DOI: 10.1016/j.jglr.2012.12.006 VOLUME: 40 LENGTH: 12 pages

Conservation and management of fisheries and aquatic communities in Great Lakes connecting channels

DOI: 10.1016/j.jglr.2014.03.003 VOLUME: 40 LENGTH: 6 pages

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

LENGTH: 8 pages

Noninvasive Evaluation of Heavy Metal Uptake and Storage in Micoralgae Using a Fluorescence Re~o_nance . Energy Transfer-Based Heavy Metal Biosensor


We have developed a fluorescence resonance energy transfer (FRET)-based heavy metal biosensor for the quantification of bioavailable free heavy metals in the cytoplasm of the microalga Chlamydorrwnas reinhardtii. The biosensor is composed of an end-to-end fusion of cyan fluorescent protein (CFP), chicken metallothionein IT (MT-IT), and yellow fluorescent protein (YFP). In vitro measurements of YFP /CFP fluorescence emission ratios indicated that the addition of metals to the purified biosensor enhanced FRET between CFP and YFP, consistent with heavy metal-induced folding of MT-II. A maximum YFP /CFP FRET ratio of 2.8 was observed in the presence of saturating concentrations of heavy metals. The sensitivity of the biosensor was greatest for
Hg2+ followed by Cd2+ ~ Pb2+ > Zn2+ > Cu2+. The heavy metal biosensor was unresponsive to metals that do not bind to MT-II (Na+ and Mg2+). When expressed in C. reinhardtii, we observed a differential metal-dependent response to saturating external
concentrations (1.6 mM) of heavy metals (Pb2+ > Cd2+) that was unlike that observed for the isolated biosensor (in vitro). Significantly, analysis of metal uptake kinetics indicated that equilibration of the cytoplasm with externally applied heavy metals occurred within seconds. Our results also indicated that algae have substantial buffering capacity for free heavy metals in their cytosol, even at high external metal concentrations.


Size, Relative Abundance, and Catch-per-unit-effort of Round Goby, Neogobius melanostomus, in Anthropogenically Modified and Natural Habitats in the Western Basin of Lake Erie

DOI: 10.1111/jai.12211 VOLUME: 29 ISSUE: 5 LENGTH: 5 pages

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


Length-Weight Relationships of the Mimic Shiner Notropis volucellua (Cope 1865) in the Western Basin of Lake Erie


Gender relationships between total and standard length (mm) were compared to weight (mg) in the mimic shiner,
Notropis volucellus for the western Lake Erie basin in the vicinity of the Bass Islands. Length and weight relationship (n=300),
length-frequency distribution, and sex ratios (n=884) from a single date from Gibraltar Island in June 2012 were analyzed for
coastal shoreline and tributaries. A strong positive correlation was found between length and weight for both males and females.
In females, a significant positive correlation exists between standard length (SL) and body weight (F=671.5, d.f.=135) and between
total length (TL) and body weight (F=681.4, d.f.=135). In males, there was also a strong positive correlation between SL and body
weight (F=1744.9, d.f.=160) and between TL and body weight (F=1656.6, d.f.=160). Combining data for the two sexes helped
determine a strong relationship between SL and body weight (F=1908.3, d.f.=299) and between TL and body weight (F=1885.9,
d.f.=299) that was consistent with the results from the individual sexes. The growth patterns of male and female mimic shiner
differed significantly for both SL (F=0.76, p>0.05, d.f.=159-134) and TL (F=0.76, p>0.05, d.f.=159-134). Age I females ranged
from 29–51 mm TL and Age I males ranged from 30–46 mm TL based on 884 individuals from Gibraltar Island. Age II females
ranged from 57–61 mm TL and Age II males ranged from 54–56 mm TL. Mimic shiner exhibit indeterminate growth and gender
influences growth patterns.

VOLUME: 112 ISSUE: 2 LENGTH: 6 pages

Research Overview: Holocene Development of Lake Erie


. This paper reviews and summarizes research on the Holocene evolutionary history of Lake Erie. New bathymetric data published in 1998 and more
recently by the National Geophysical Data Center reveal lake-fl oor features indicative of former, now inundated, shorelines. These data combined with other
recent research, permit a detailed reconstruction of Lake Erie’s complex history since the Wisconsinan ice sheet retreated some 12,000 years ago, ending a
series of glacial lakes and initiating a series of post-glacial lake stages. The lakes that have occupied the Lake Erie Basin are grouped into three phases. The
oldest phase, 14,400 to 12,000 years ago, had lake stages associated with glaciers in the basin and were higher than present Lake Erie. The middle phase,
12,000 to 4,700 years ago, had lake stages isolated from Upper Lakes drainage during a dryer climatic period and were below the present level of Lake Erie. In
the last phase, from 4,700 to present, the Lake Erie Basin received Upper Lakes drainage and the water level rose to a slightly higher stage before establishing
the present elevation through outlet erosion.

VOLUME: 112 ISSUE: 2 LENGTH: 13 pages

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

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

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

LENGTH: 18 pages

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

LENGTH: 14 pages

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

LENGTH: 6 pages
Showing: Page 1 of 12 with total 590 item(s)