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Hartung, Erik WalterAging bioretention cells: Do they still function to improve water quality?
MS, Kent State University, College of Arts and Sciences / Department of Biological Sciences
Stormwater runoff from impervious surfaces transports a variety of pollutants to freshwaters via urban drainage pathways. Bioretention cells are a stormwater control measure being widely adopted with the goal of receiving, infiltrating and improving quality of stormwater before it enters surface waters. However, there are uncertainties about the spatial distribution and concentration of toxic metals that accumulate and concerns about changes in hydrologic function of aging bioretention cells. This study sought to address those concerns using a survey of 26 parking lot bioretention cells in the greater Cleveland area, ranging in age from <1 to 7 years of service. Bioretention cells were found to accumulate Cu, Pb and Zn in their media through time, but the distribution of these toxic metal pollutants was homogenous with respect to depth and distance from the stormwater flowpath. The concentration of metals in bioretention cell media were well below EPA soil contamination thresholds. Bioretention cells were found to have reduced hydraulic conductivity as they age, but bioretention cells less than eight years old still met EPA standards for hydrologic function. Therefore, regular maintenance of bioretention cells may be needed to remove sediment and improve hydrologic function, but no remediation would be needed for toxic metals. It is expected that bioretention cells function to capture, infiltrate and remove pollutants from stormwater runoff, leading to water quality improvement downstream. However, there is a lack of knowledge regarding active bioretention cells' ability to perform these functions over the long-term. This study aimed to elucidate the function of bioretention cells for removal of toxic metal pollutants (Cu, Pb and Zn) from runoff over 7 years of service time. This study also sought to address the effects road salt may have on bioretention's ability to filter or retain toxic metal pollutants from stormwater. Using leach columns constructed with media from 19 active bioretention cells ranging in age from <1 to seven years old, this study found that age is not a good predictor of bioretention cell functioning for metal removal. Bioretention cells were found to function well for removing low concentrations of metals from stormwater, but had reduced functioning for removal of high concentrations of metals. Bioretention cells' ability to remove metals from stormwater was found to be similar at different locations within the cells. Road salt was found to reduce the functioning of aged bioretention cells (7 years of service) for Pb and Zn removal from stormwater, but had no effect on functioning for Cu removal. Bioretention cells less than eight years in age were found to be able to reduce the concentration of metals in stormwater to concentrations below EPA thresholds for freshwater, but road salt may reduce bioretention's ability to reduce the concentration of Pb and Zn in stormwater.

Committee:

David Costello (Advisor)

Subjects:

Aquatic Sciences; Biogeochemistry; Biology; Ecology; Environmental Engineering; Environmental Management; Environmental Science; Environmental Studies; Freshwater Ecology; Hydrologic Sciences; Hydrology; Land Use Planning; Natural Resource Management; Water Resource Management

Keil, Emily J.Investigation of Nutrient Limitation of the Biofilm Community in Acid Mine Drainage Impaired and Remediated Streams
Master of Science (MS), Ohio University, 2016, Plant Biology (Arts and Sciences)
Acid Mine Drainage (AMD) from pre-regulation mining affects streams in the Appalachian region resulting in acidic waters with high dissolved metal content. Previous studies have shown remediated stream segments have better water quality and biological communities than untreated streams, but these segments have not attained the same biological quality as streams unaffected by AMD. Phosphorus limitation of the biofilm community has been hypothesized as a contributing factor. Nutrient limitation was tested in four stream categories using nutrient diffusing substrates: AMD, transitional, recovered and unimpacted. Chlorophyll a, a measure of photosynthetic biomass, was significantly higher in phosphorus treatments. In addition, the phosphorus treatments had lower phosphorus-acquiring enzyme activities compared to the control. The phosphorus with nitrogen treatment showed an increase in polyunsaturated fatty acids, having higher nutritional value for grazers. This study demonstrated that nutrient availability has a substantial impact on the photosynthetic component of biofilms in impaired and remediated streams.

Committee:

Morgan Vis (Advisor); Jared DeForest (Committee Member); Kelly Johnson (Committee Member)

Subjects:

Ecology; Freshwater Ecology

Keywords:

nutrient diffusing substrates; acid mine drainage; biofilm; fatty acids; extracellular enzyme activity; remediation; nutrient limitation

Ligocki, Isaac YoungExpanding Scales of Influence: Behavioral, Physiological, and Reproductive Implications of Relative Power within Social Groups
Doctor of Philosophy, The Ohio State University, 2015, Evolution, Ecology and Organismal Biology
Individual behavior and the social interactions of individuals in groups are related to one another. Individuals may respond dynamically to interactions with other group members, and their behavior may influence that of those they interact with. I define such interactions as direct interactions, and the resulting effects as direct effects. Individual behavior may also influence and be influenced by the behavior and interactions of group members with whom they do not directly interact. I define such interactions as third party interactions, and the resulting effects as third party effects. In cooperatively breeding groups, in which some group members forego or limit their own reproduction and provide care for the offspring of other group members (alloparental care), third party interactions are predicted to have potentially dramatic effects on group characteristics because group members of different sex or social status may be in conflict regarding the extent of reproductive skew or expectation of alloparental care. The primary aim of the studies in this dissertation was to investigate the impact of third party interactions in the cooperatively breeding cichlid fish Neolamprologus pulcher through lab- and field-based studies as well as a game theoretical model. In chapter 2, I determined that the relative size of the dominant male and female fish influenced their direct interactions with one another as well as their relative response towards conspecific and heterospecific intruders on their territory. In chapter 3, I found that dominant fish are in conflict regarding the presence and role of subordinate male and female group members. In chapter 4, I concluded that direct agonistic interactions did not influence subordinate female cortisol levels, but one measure of agonism between the dominant pair was associated with elevated cortisol levels in subordinate female fish. In chapter 5, I investigated how members of naturally formed groups respond to territorial intrusions (determined to be perceived as potential joiners to the group) depending on their social status within the group and whether a vacancy existed in the group which the intruding fish could fill. Size-matched subordinate fish and dominant females were most aggressive towards intruders. Dominant and subordinate fish also shifted their response in opposite ways after the removal of a large subordinate group member, suggesting dominants and subordinates are not in agreement regarding group size or the addition of potential joiners to the group. In chapter 6, I developed game theoretical models to predict when subordinate females should attempt to reproduce within groups, and examined how the order of decisions in games influences their outcome. Collectively, this research builds on previous work on conflict within animal groups by providing evidence that individual group members do not always agree on the role and presence of other group members. I extend this body of research by showing that this lack of consensus leads to third party effects within groups which may have implications for group size and membership, reproductive skew in groups, and the extent to which subordinates participate in alloparental care.

Committee:

Ian Hamilton (Advisor); Elizabeth Marschall (Committee Member); Steven Rissing (Committee Member); J. Andrew Roberts (Committee Member)

Subjects:

Animals; Behavioral Sciences; Biology; Ecology; Endocrinology; Evolution and Development; Freshwater Ecology; Zoology

Keywords:

cooperation; conflict; social behavior; third-party effects; cooperative breeding; Neolamprologus pulcher; Lake Tanganyika

Wilbur, Cricket C.A History of Place: Using Phytolith Analysis to Discern Holocene Vegetation Change on Sanak Island, Western Gulf of Alaska
Ph.D., Antioch University, 2013, Antioch New England: Environmental Studies
This study investigated a terrestrial climate proxy, phytoliths, as a complimentary approach to documenting the dynamics of present and past vegetation on Sanak Island, the largest island in a small island group in the eastern Aleutian archipelago, and as a new basis by which to interpret Holocene environmental variability in Alaska. A phytolith reference collection was established from 59 selected plant species of maritime tundra belonging to 27 families. The grass species and a sedge species produced abundant phytolith forms whereas the majority of dicotyledons in this study were trace producers of phytoliths. A paleoenvironmental reconstruction from fossil phytoliths recovered from a continuous lake sediment core indicates that sedges and cool season grasses were present on this landscape throughout most of the Holocene suggesting the long-term dominance of maritime climate on island vegetation. Adaptation and resilience of the modern vegetation on Sanak Island to a warming climate is suggested by the densities of silicified stomata recovered from six species of grasses, one species of fern, and one species of horsetail when compared to the paleoenvironmental reconstruction. The changes in stomata frequency in the plants on Sanak Island today may have connections to future changes in regional and global climate through the water cycle. Our changing climate is forcing ecosystems to migrate, acclimate or go extinct demonstrating that new insights into ecosystem responses to present and past environmental variation, and forecasting future ecological change are especially relevant today for ecologic and economic sustainability. The electronic version of this Dissertation is at OhioLink EDT Center, www.ohiolink.edu/etd.

Committee:

James W. Jordan, PhD (Committee Chair); Charles G. Curtin, PhD (Committee Member); Deborah M. Pearsall, PhD (Committee Member)

Subjects:

Archaeology; Botany; Climate Change; Conservation; Earth; Ecology; Environmental Science; Freshwater Ecology; Geology; Limnology; Native Americans; Natural Resource Management; Paleobotany; Paleoclimate Science; Paleoecology; Plant Biology; Pollen

Keywords:

Paleolimnology; Phytoliths; Phytolith Analysis; Aleutian Islands; Sanak Island; Western Gulf of Alaska; Stomata; Maritime tundra; Grasses; Dicotyldons; Arctic ecosystems; Climate change; Paleoenvironmental reconstruction; Holocene; Lake sediment

Farmer, Troy MClimate Change Effects on Lake Erie Yellow Perch Reproduction and Recruitment
Doctor of Philosophy, The Ohio State University, 2013, Evolution, Ecology and Organismal Biology
Climate warming is expected to positively affect cool-water, temperate fish populations by lengthening the growing season and expanding thermal habitats suitable for positive growth. Yet, little is known about how a corresponding shortened winter might affect temperate fish populations, especially for species that require a prolonged period of cold temperature during the winter prior to spawning for proper ovary development. Additionally, events such as hypolimnetic hypoxia (O2 < 2 mg/L), are expected to increase with continue warming. We hypothesized that climate change would negatively affect temperate fish populations by 1) increasing bottom hypoxia during summer, which can reduce energy reserves (fish condition) prior to winter, when ovaries develop for many species, and 2) increasing winter water temperature, which could increase basal metabolic rates during winter (i.e., reduce energy available for ovary development) and disrupt thermal requirements necessary for proper ovary development. To test these hypotheses, we investigated the effects of winter temperature and female condition on Lake Erie yellow perch Perca flavescens reproductive development, egg and larval quality, and ultimately, fall juvenile abundance (a strong predictor of future recruitment to the yellow perch fishery in Lake Erie). Towards this end, we conducted laboratory experiments, a multi-year field study, and historical analyses. In our laboratory experiments, female yellow perch exposed to a long winter produced higher quality eggs (i.e., in terms of size, energetic, and lipid content) that both hatched at higher rates and produced larger larvae than lower quality eggs from females exposed to a short winter (Chapters 2 and 3). Counter to our hypotheses, reduced female condition entering winter did not adversely affect reproductive success (Chapter 3). Additionally, field and laboratory studies found that when spring warming happened extremely early, yellow perch spawning did not fully adjust, increasing the possibility of a mis-match between first-feeding larvae and their zooplankton prey (Chapter 2). Finally, we show through historical analyses that the negative effect of warm winters on Lake Erie yellow perch juvenile abundance appears to be consistent over 42 years (i.e., 1969-2010), and has persisted throughout a large-scale, nutrient-driven regime shift and restructuring of the food-web due to numerous introductions of invasive species (Chapter 4). Our research offers a previously unrecognized mechanism by which climate change can threaten temperate fish populations, through reductions in reproductive success. Our results also may have relevance to fisheries managers seeking to better anticipate the responses of fish populations to climate change. Specifically, given that our study has identified mechanisms that appear to be responsible for long-term population dynamics, our findings may allow for managers to monitor the appropriate variables (i.e., winter thermal regime) necessary to predict annual recruitment to the fishery for Lake Erie yellow perch. Additionally, because our study species has similar life-history and physiological requirements not unlike many other cool-water, temperate fishes, our findings may have relevance to fish populations in many ecosystems.

Committee:

Stuart Ludsin, Dr. (Advisor); Elizabeth Marschall, Dr. (Advisor); Konrad Dabrowski, Dr. (Committee Member); Maria Miriti, Dr. (Committee Member)

Subjects:

Aquatic Sciences; Biology; Ecology; Fish Production; Freshwater Ecology; Limnology; Zoology

Seidel, Richard AlanConservation Biology of the Gammarus pecos Species Complex: Ecological Patterns across Aquatic Habitats in an Arid Ecosystem
Doctor of Philosophy, Miami University, 2009, Zoology

This dissertation consists of three chapters, each of which addresses a topic in one of three related categories of research as required by the Ph.D. program in ecology as directed through the Department of Zoology at Miami University.

Chapter 1, Phylogeographic analysis reveals multiple cryptic species of amphipods (Crustacea: Amphipoda) in Chihuahuan Desert springs, investigates how biodiversity conservation and the identification of conservation units among invertebrates are complicated by low levels of morphological difference, particularly among aquatic taxa. Accordingly, biodiversity is often underestimated in communities of aquatic invertebrates, as revealed by high genetic divergence between cryptic species. I analyzed PCR-amplified portions of the mitochondrial cytochrome c oxidase I (COI) gene and 16S rRNA gene for amphipods in the Gammarus pecos species complex endemic to springs in the Chihuahuan Desert of southeast New Mexico and west Texas. My analyses uncover the presence of seven separate species in this complex, of which only three nominal taxa are formally described. The distribution of these species is highly correlated with geography, with many present only in one spring or one spatially-restricted cluster of springs, indicating that each species likely merits protection under the U.S. Endangered Species Act. I present evidence suggesting that habitat fragmentation, long-distance colonization, and isolation-by-distance have occurred at different temporal and spatial scales within this system to produce the lineages that I report.

Chapter 2, Detecting conservation units using morphological versus molecular criteria: evaluating the Gammarus pecos species complex as a test case, compares the results of morphological versus molecular biodiversity assessments within the G. pecos species complex. I compared results from an earlier morphology-based study to my results from screening 166 COI gene sequences according to Moritz’ Evolutionarily Significant Unit (ESU) concept and a DNA barcode-based Species Screening Threshold (SST) concept. I found strong concordance between the two molecular screening methods, but these two molecular methods separated populations as distinct from one another whereas the morphological method alone failed to separate the same populations. Overall, I found that morphological and molecular techniques for biodiversity estimation should be combined, when possible, to produce a powerful tool for addressing taxonomic and conservation issues.

Chapter 3, Salinity tolerance as a potential driver of ecological speciation in amphipods (Gammarus spp.) from the northern Chihuahuan Desert, examines population level responses to salinity. My results suggest barriers to gene flow between populations as a result of ecologically-based divergent selection, and that tolerance to habitat salinity has structured biodiversity across springs in the northern Chihauhuan Desert. Furthermore, salinity tolerance is correlated with environmental salinity. This work shows a role for both putatively neutral processes (e.g. isolation and genetic drift) and natural selection (acting on population-level physiological responses to habitat salinities).

Taken together, these results provide clues important for future biodiversity investigations in geographically isolated aquatic habitats, and shed light on the understudied and underestimated levels of biodiversity present in desert spring systems.

Committee:

David Berg, PhD (Advisor); John Bailer, PhD (Committee Member); Brian Keane, PhD (Committee Member); Nancy Solomon, PhD (Committee Member); Bruce Steinly, PhD (Committee Member)

Subjects:

Bioinformatics; Biology; Biostatistics; Ecology; Environmental Science; Freshwater Ecology; Genetics; Hydrology; Molecular Biology; Zoology

Keywords:

Conservation genetics; Endemic; Aquatic invertebrate; Biogeography; Salinity; Ecology; Phylogeography; Phylogenetics

Marion, Jason W.Protecting Public Health at Inland Ohio Beaches: Development of Recreational Water Quality Indicators Predictive of Microbial and Microcystin Exposure
Doctor of Philosophy, The Ohio State University, 2011, Public Health
Inland lakes are prone to contamination from a variety of sources within their watersheds. The changing environment can influence transport and fate of fecal indicators and may also influence the growth of harmful cyanobacteria, thereby occasionally creating health-related water quality concerns for recreational water users. To date, epidemiological and limnological studies pertaining to fecal indicators and harmful cyanobacteria have been limited with respect to inland U.S. lakes. The primary goals of this dissertation were to (1) evaluate illness risks associated with the fecal indicator E. coli, and (2) evaluate predictive tools potentially useful for the rapid prediction of E. coli densities and health-related concentrations of cyanotoxins in inland Ohio lakes. Through an epidemiological study and the collection of water quality data, predictive models for human illness and water quality advisories were developed. The relationship between water quality indicators and reported adverse health outcomes among users an inland Ohio beach were examined. Human health data collected via a prospective cohort study over 26 swimming days during the 2009 swimming season at East Fork Lake demonstrated that wading, playing or swimming in the water was found to be a significant risk factor for GI illness (adjusted odds ratio (aOR) of 3.2; CI = 1.1, 9.0). Among water users (n = 806), E. coli density was associated with elevated GI illness risk where the highest E. coli quartile was associated with an aOR of 7.0 (CI = 1.5, 32). Upon observing a significant illness association with E. coli densities among swimmers, the need for rapidly estimating E. coli densities was determined to have merit. Current approaches for quantifying E. coli densities rely on culture-based methods that require 18 or more hours to obtain a result. Using rapidly measured water quality parameters (e.g., total phosphorus, secchi depth, chlorophyll A), univariable models for rapidly estimating health-related E. coli densities were developed and considered for inland Ohio lakes using 182 beach water samples collected from seven Ohio lakes. Univariable logistic regression revealed that deviations in lake-specific water quality as measured by total phosphorus (p < 0.001), phycocyanin pigment (p = 0.018), and trophic state index (TSI) (p = 0.006) were predictive of E. coli levels exceeding recreational water quality criteria. Using the same samples, models were constructed for estimating cyanotoxin concentrations. Microcystin levels exceeding the 4 micrograms/L low risk threshold set by the World Health Organization were detected by ELISA in 48 of 182 (26.4%) samples. A multivariable logistic regression model using practical and real-time measures of in vivo phycocyanin and secchi depth was constructed to predict beach conditions exceeding the low risk threshold for microcystin. The model (p = 0.030) predicted microcystin levels >4 micrograms/L with acceptable discrimination as indicated by the area under the ROC curve (0.795). This study indicates a significant health risk for inland beach users and demonstrates the potential to predict health-related hazard levels using practical real-time measures are possible, enabling opportunities for interventions that protect public health.

Committee:

Timothy J. Buckley, PhD (Committee Chair); Jiyoung Lee, PhD (Committee Co-Chair); Stanley Lemeshow, PhD (Committee Member); John R. Wilkins, III, PhD (Committee Member)

Subjects:

Biology; Ecology; Environmental Health; Environmental Science; Epidemiology; Freshwater Ecology; Limnology; Public Health; Recreation

Keywords:

E. coli; fecal indicator; epidemiology; recreational water; microcystin; harmful algal bloom; cyanotoxin; phycocyanin; trophic state index; inland lakes; Ohio; gastrointestinal illness; beach water quality;

Briland, RuthOptimizing Larval Fish Survival and Growth through an Analysis of Consumer and Resource Interactions in Percid Culture Ponds
Master of Science, The Ohio State University, 2010, Evolution, Ecology, and Organismal Biology
Management of aquaculture systems should be based on ecologically sound principles and experimentation to determine species- and site-specific management practices that both optimize fish production and extend our understanding. Herein, we exemplify an approach to meet this goal, evaluating the effectiveness of three common management levers: pond fertilization regimen, pond filling and stocking schedule, and fry stocking rate, on larval production of two popular percid fish, walleye (Sander vitreus) and saugeye (S. vitreus x S. canadense), at Senecaville State Fish Hatchery in Ohio. These levers are based on established ecological principles and hypotheses concerning fish recruitment, including resource-driven or “bottom-up” control, the match-mismatch hypothesis, and predator-driven or “top-down” control, respectively. Our experiments demonstrate that “top-down” effects (i.e., fish predation on zooplankton) drive fish growth, and we recommend that fry stocking density be reduced to les than 20 percid fry/m3 to yield suitable fish size at harvest. At higher stocking rates, percid planktivory can deplete zooplankton prey resources, resulting in poor fish growth and unacceptably small percid size at harvest. The other two management levers (i.e., manipulating fertilization rate and pond filling and stocking schedules) had little impact on percid production; however, these ecological management levers may be critical for successful fish production at other hatcheries, given different environmental conditions (e.g., source water productivity) or fish taxa. Overall, we illustrate an ecologically sound approach to assess management protocols for fish production in aquaculture settings that can be broadly applied to culture of many species at a variety of culture locations.

Committee:

Stuart Ludsin, PhD (Advisor); David Culver, PhD (Advisor); Roy Stein, PhD (Committee Member)

Subjects:

Aquaculture; Ecology; Fish Production; Freshwater Ecology

Keywords:

larval fish ecology; aqucuaculture; walleye; saugeye

Amey, Katherine SpringerHydrology And Predictive Model Of Headwater Streams And The Groundwater/Surface Water Interactions Supporting Brook Trout Habitat In Northeast Ohio
PHD, Kent State University, 2011, College of Arts and Sciences / Department of Geology

The hydrology and hydrogeology of a set of eight cold-water streams in Lake and Geauga Counties in northeast Ohio were evaluated in order to develop a new predictive model for the successful introduction of native Ohio brook trout (Salvelinus fontinalis). The model may be used to assess future sites for potential introduction of this threatened species. A field study was conducted from February 2009 to May 2010 in streams where the brook trout had been previously introduced. These streams were good candidates for study because four had been designated successful, two variable, and two failed in terms of the brook trout’s ability to flourish by the Ohio Department of Natural Resources (ODNR). The field study examined the groundwater/surface water interaction in the hyporheic zones, ecologically important areas where brook trout build their spawning beds, known as redds. To improve on the current model of brook trout introduction, and subsequent habitat suitability index (HSI), this study determines if there is a relationship between the temporal and spatial variability of groundwater input into the stream’s hyporheic zone, and successful, variable or non-successful outcome of brook trout introduction. Nested minipiezometers at the riffle head and tail allowed the study of the water quality, hydrogeology, stable isotopes (δ18O, δD), soils, and ultimately determined the source of coldwater input to the streams. Benthic macroinvertebrates and ostracodes were analyzed to assess the biological integrity of the stream.

Factors found to be significant in successful Ohio trout populations were hydrology of the streams, including low discharge (Q<0.13-0.51 ft3/s), and hydrogeology of the aquifer, most importantly, a high hydraulic conductivity of the headwaters (K>100 gpd/ft2). Key features of successful streams include high percent canopy cover (40%-55%) or high percent instream cover (18%-37%), and a high number of benthic macroinvertebrate cold-water taxa (10-16 species). A long-term water temperature study over both winter and summer seasons (successful stream yearly average hyporheic water temperature 4.6°C-17.2°C and surface water temperature 0.3°C-18.0°C) is recommended prior to introduction. Successful streams are part of an ecologically sensitive “surface system”, and should be protected in the headwaters of streams sustaining the brook trout population.

Committee:

Alison Smith (Advisor); Mandy Munro-Stasiuk (Committee Member); Donald Palmer (Committee Member); Daniel Holm (Committee Member); Ferenc de Szalay (Committee Member)

Subjects:

Aquatic Sciences; Ecology; Environmental Geology; Freshwater Ecology; Geology; Hydrologic Sciences; Hydrology

Keywords:

Hydrology; Hydrogeology; Groundwater Surface Water Interaction; Vertical Hydrauic Gradient; Precipitation; Temperature Study;Brook Trout; Cold Water Streams; Stable Isotopes; Benthic Macroinvertebrates; Northeast Ohio; Predictive Model

Gray, Jonathon B.Reference Diatom Assemblage Response to Transplantation into a Stream Receiving Treatment for Acid Mine Drainage in Southeastern Ohio
Master of Science (MS), Ohio University, 2011, Environmental Studies (Arts and Sciences)
Acid mine drainage (AMD) is a prevalent legacy of coal mining within Appalachia. Streams receiving AMD effluent are drastically altered both chemically and biologically. Hewett Fork, a stream in southeastern Ohio, is one such affected stream. Although treatment methods have reduced acidity considerably downstream, the ability of Hewett Fork to sustain a biological community compared to those found in reference conditions remains unclear. To assess this, tiles colonized with diatom assemblages from an unimpacted stream were transplanted into Hewett Fork along a stream health gradient, from poor to good, and sampled after one, three, and six weeks in the treated stream. Chlorophyll a concentrations and species diversity metrics were calculated to compare reference assemblages to transplanted assemblages. Results suggested that after an initial one week acclimation period, assemblages at the uppermost and lowermost sites along the reach were relatively similar to those found in reference conditions, while sites within the middle region continued to show signs of impairment, although the factor(s) causing this impairment remain unknown. These findings suggest that although treatment has been effective on a site-specific basis, the expected linear-response to treatment may not be achieved due to underlying factors that are inhibiting reference-like biological communities from reestablishing within the affected stream reach.

Committee:

Morgan Vis, PhD (Advisor); Kelly Johnson, PhD (Committee Member); Brian McCarthy, PhD (Committee Member)

Subjects:

Aquatic Sciences; Biology; Conservation; Ecology; Environmental Science; Environmental Studies; Freshwater Ecology; Natural Resource Management; Water Resource Management

Keywords:

diatom; acid mine drainage (AMD); transplantation; stream; recovery; sacrifice zone; ecosystem structure

Jacoby, Jill BethArt, Water, and Circles: In What Ways Do Study Circles Empower Artists to Become Community Leaders around Water Issues
Ph.D., Antioch University, 2009, Leadership and Change
This research explored the use of study circles as a means of engaging artists in dialogue with their peers about water related concerns. The question driving this research was, “In what ways do study circles empower artists to become community leaders around water issues?” Secondary questions focused on emerging environmental, water, and social justice themes as well as examples of increased water awareness and behavior change occurring as a result of individual participation in the study circles. Artists have a unique way of commanding attention and communicating about environmental concerns while functioning as catalysts for activism on a variety of social topics. Barndt (2004, 2006,2008) has written extensively about the nexus between community-based art, activism and action research, as well as identifying the important differences in participation and intent behind community-based art versus art as commodity. This research incorporated the use of study circles (also known as dialogue groups, dialogue circles, or talking circles) with artists to learn how study circles empower artists to become community leaders. Literature focusing on civic engagement and the arts has looked at the process of utilizing the arts to engage the public in dialogue about a social concern. This research differs in that it focused on how a dialogue process impacts artists. Seventeen artists participated in four study circle sessions that encouraged in-depth dialogue on water quality concerns. Lohan’s (2008) Water Consciousness: How we all Have to Change to Protect our Most Critical Resources was used as a study guide and to focus the dialogue sessions. The artists participated in one-on-one semi-structured interviews to help clarify the relationship between the study circles and their own water awareness as well as community building, collaboration, and/or leadership among the artists. A focus group was used to obtain feedback on the value of study circles for social change. Key findings from this research conclude that the study circles brought about new methods for problem identification and solving, individual behavior changes, a deeper understanding for others, and the dialogue provided a powerful catalyst for collaboration, leadership and relationship building. The electronic version of this dissertation is available in the open access OhioLink ETD Center, http://etd.ohiolink.edu/

Committee:

Jon Wergin, PhD (Committee Chair); Laurien Alexandre, PhD (Committee Member); Steve Chase, PhD (Committee Member); David Attyah, MFA (Other)

Subjects:

Adult Education; Ecology; Environmental Science; Fine Arts; Freshwater Ecology; Personal Relationships; Science Education; Social Research

Keywords:

action research; study circles; dialogue circles; popular education; water resources; activist art; social change; public art; environmental art; community-based art; collaborative leadership; environmental leadership; civic engagement

DuFour, Mark RHydroacoustic Quantifi cation of Lake Erie Walleye (Sander vitreus) Distribution and Abundance
Doctor of Philosophy, University of Toledo, 2017, Biology (Ecology)
This work was motivated to improve understanding of Lake Erie walleye (Sander vitreus) distribution and abundance. Lake Erie walleye are large migratory fish that are ecologically and economically important within the Great Lakes region. The population is monitored partly through a fishery independent gill net survey carried out by the Ohio Department of Natural Resources - Division of Wildlife (ODNR-DOW). However, high variation in annual CPUE has interfered with this survey's ability to identify changes in walleye abundance. Therefore, the ODNR-DOW was interested in the potential of coupling hydroacoustic sampling with the existing gill net survey to quantify Lake Erie walleye distribution and abundance. In this dissertation I address four major questions that helped optimally couple hydroacoustic and gill net surveys. In Chapter 1, I evaluated the impact of beam compensation on surveyed target strength (TS) data. I found that using an intermediate beam compensation (18 dB), greater than conventionally suggested (6 dB), provided a higher quantity of TS data with minimal impact on TS data quality. Increased beam compensation led to higher encounter rates and more TS data per fish, which ultimately provided a better characterization of the low density walleye population. In Chapter 2, I evaluated the influence of vessel size and day-night period on the availability of the walleye population to a hydroacoustic survey. I found that walleye were less likely to avoid smaller sampling vessels, but the vessel size effect decreased with depth. Also, during the fall period of the gill net survey, walleye were more available to hydroacoustic sampling at night. Finally, although vessel size and day-night sampling period are important logistical consideration, capturing spatial distributions across the survey should be prioritized in future surveys. In Chapter 3, I compared gill net catch-per-unit-effort (CPUE) and hydroacoustic abundance estimates from across a large survey area with varied environmental conditions. I found that the relationship between gill net CPUE and abundance changed across the survey along environmental gradients. This indicated that sub-optimal catchability and gear efficiency in the gill net survey limits its ability to quantify changes in abundance, and adding a hydroacoustic component to this survey would be beneficial. In Chapter 4, I developed a method to infer species composition of the hydroacoustic data while addressing many apportionment challenges, such as: limited and variable species composition data, subjective threshold decisions, and uncertainty in mean TS estimates. This method improved species composition estimates, propagated uncertainty from both sampling methods, and eliminated subjective threshold decisions. Distribution estimates corresponded with known patterns of walleye movements and ecology, while survey-wide estimates were comparable to independent estimates based on annual stock assessments. Using the methods outlined here in, hydroacoustics could be successfully coupled with the existing ODNR-DOW gill net survey to improve quantification of Lake Erie walleye distribution and abundance.

Committee:

Christine Mayer, PhD (Committee Co-Chair); Song Qian, PhD (Committee Co-Chair); Jonathan Bossenbroek, PhD (Committee Member); Patrick Kocovsky, PhD (Committee Member); David Warner, PhD (Committee Member)

Subjects:

Aquatic Sciences; Biology; Biostatistics; Ecology; Environmental Science; Freshwater Ecology; Natural Resource Management

Keywords:

Lake Erie, walleye, Sander vitreus, gill net, survey, hydroacoustic, target strength, beam compensation, avoidance, behavior, availability, catchability, efficiency, apportionment, species composition, threshold, uncertainty, Bayesian, hierarchical, model

Evans, Joshua R.Transcriptional Regulation of Select Light-Harvesting Genes during Photoacclimation in Lympha mucosa gen. et sp. prov. (Batrachospermales, Rhodophyta)
Master of Science (MS), Ohio University, 2017, Plant Biology (Arts and Sciences)
The strictly freshwater red algal order Batrachospermales has undergone numerous taxonomic rearrangements in the recent past to rectify the paraphyly of its largest genus Batrachospermum. These systematic investigations have led to the description of new genera and species as well as re-circumscription of some taxa. Specimens collected from two locations in southeastern USA were initially identified as being allied to Batrachospermum sensu lato, but could not be assigned to any previously described species. Comparison of DNA sequence data for two gene regions and morphology with other batrachospermalean taxa resulted in the proposal of a new monospecific genus Lympha mucosa gen. et sp. prov. to accommodate these specimens. A phylogeny of L. mucosa showed it is sister to the genus Volatus, but has morphological similarities with Batrachospermum sections Turfosa and Virescentia. This new taxon adds to the freshwater red algal diversity of southeastern USA, a region already known for biodiversity and high endemism of the aquatic flora and fauna. Lympha mucosa occurs in open and shaded sites of temperate streams and is abundant during summer months. Although most freshwater red algal taxa are considered shade-adapted, many species exhibit differences in photosynthetic rates and characteristics that indicate they have a much greater ability to acclimate to higher irradiances. Specimens of L. mucosa were collected from open (sun-acclimated) or shaded (shade-acclimated) sites and were exposed to low (<20 µmol photon m-2 s-1) or high (220 µmol photon m-2 s-1) for 72h in controlled conditions to examine photoacclimation. To observe regulation for this process at the transcriptional level, the L. mucosa plastid genome was assembled to provide sequence data for photosynthetic genes involved with light harvesting machinery. Of the six light-harvesting genes selected, two involved with photosystem I and one involved with phycoerythrin synthesis were downregulated at high light. This is the first evidence of transcriptional regulation as a potential mechanism for acclimation to varying irradiances in a freshwater red alga.

Committee:

Morgan Vis (Advisor); Sarah Wyatt (Committee Member); Harvey Ballard (Committee Member)

Subjects:

Aquatic Sciences; Bioinformatics; Biology; Biostatistics; Ecology; Evolution and Development; Experiments; Freshwater Ecology; Genetics; Molecular Biology; Organismal Biology; Plant Biology; Plant Sciences; Systematic

Keywords:

photoacclimation; red algae; gene expression; aquatic biology; phylogeny; photosynthesis

Michael, TaylorInvertebrate Activities in Wetland Sediments Influence Oxygen and Nutrient Dynamics at the Sediment-water Interface
BS, Kent State University, 2018, College of Arts and Sciences / Department of Biological Sciences
Invertebrate activities at the sediment-water interface can facilitate nutrient retention, release, and transformation by changing the nature of oxygen penetration into anoxic sediments, influencing geochemical and microbial-mediated processes. By reworking sediment and conveying oxygenated surface water into deeper anoxic sediment through burrowing activities, bioturbating invertebrates influence nutrient cycling in wetlands sediments. To test the effects of bioturbators on oxygen introduction and nutrient fluxes, we investigated the impacts of two functionally different bioturbators at a range of four densities using a microcosm study. We measured sediment oxygen penetration depth at small-scale resolution using microelectrode sensors and analyzed surface water nutrients weekly over four weeks. Results indicate increased oxygen penetration in regions of normally anoxic sediment with the presence of each of the two bioturbation modes. In general, we observed negative phosphorus fluxes (i.e., into the sediment) with increasing bioturbator densities, indicating retention in the sediment due to bioturbation activities. These activities caused enough retention of phosphorus to counteract the phosphorus released by bioturbator excretion alone. There was a flux of nitrate into the surface water, likely driven by invertebrate excretion of ammonia followed by an oxidative process such as nitrification. This investigation contributes to the growing understanding of how organisms influence nutrient cycling in wetlands, which are hotspots for biogeochemical processing.

Committee:

Lauren Kinsman-Costello (Advisor); Andrea Fitzgibbon (Other); David Costello (Committee Member)

Subjects:

Biogeochemistry; Ecology; Freshwater Ecology; Geochemistry

Keywords:

Bioturbation; bioturbation modes; invertebrates; freshwater ecosystems; wetlands; biogeochemistry; nutrient exchange

Budnik, Richard RAssessment of Site-Fidelity and Straying in Lake Erie Steelhead Trout
Doctor of Philosophy (Ph.D.), Bowling Green State University, 2017, Biological Sciences
This dissertation examines straying in Lake Erie steelhead (Oncorhynchus mykiss) and investigates how stocking practices can influence the propensity of steelhead to stray. The Lake Erie steelhead fishery generates millions of dollars in revenue each year for local economies in New York, Ohio, Pennsylvania, Michigan, and the province of Ontario. This fishery is overwhelmingly dominated by stocking from each of the four contiguous US states, and approximately 1.8 million juvenile steelhead are stocked each year to sustain population numbers. River-spawned salmonids generally exhibit high rates of philopatry, while for stocked fish straying rates of up to 15% are common. In Chapter I, we quantify the proportion of straying adult steelhead in five Lake Erie tributaries using state-hatchery specific otolith chemical signatures to identify sources. We also investigate the prevalence of naturally produced fish and identify spatial differences in the proportion of strays at different stream locations within two Lake Erie tributaries. Because straying proportions were found to be high in New York, in Chapter II an otolith back-calculation method was used to investigate the influence of size at stocking on the survival of juvenile steelhead released by the New York hatchery program. In Chapter III, we investigate additional drivers of straying by using dual-frequency identification sonar (DIDSON) to estimate survival and tributary residence time of juvenile steelhead stocked into a small Lake Erie tributary. Patterns in emigration, and the role of environmental factors and individual size on emigration timing were also investigated. In Chapter IV, we identify the prevalence of aragonite versus vaterite sagittal otoliths in steelhead raised in Lake Erie hatcheries. We then present a technique to use sagittal otoliths that have transitioned from aragonite to vaterite to help develop otolith chemistry signatures of steelhead from different hatchery sources in Lake Erie. This research was an attempt to identify potential drivers of straying in Lake Erie steelhead. From an applied management perspective, we attempted to identify straying proportions in different Lake Erie tributaries and examine how differential stocking practices may influence overall survival and return rates. Straying is a complex process driven by a number of different biotic and abiotic factors. The identification of mechanisms that increase straying, especially those which can be controlled by hatchery managers, would be invaluable and greatly advance our ability to manage steelhead populations.

Committee:

Jeffrey Miner (Advisor); Kevin Pangle (Committee Member); Wiegmann Daniel (Committee Member); Moore Paul (Committee Member); Gomezdelcampo Enrique (Other)

Subjects:

Aquatic Sciences; Biology; Ecology; Fish Production; Freshwater Ecology

Keywords:

steelhead; Lake Erie; straying; otolith microchemistry; LA-ICP-MS; otolith back-calculation; DIDSON; vaterite

Jackson, Breeanne KathleenThe role of wildfire in shaping the structure and function of California `Mediterranean’ stream-riparian ecosystems in Yosemite National Park
Doctor of Philosophy, The Ohio State University, 2015, Environment and Natural Resources
Although fire severity has been shown to be a key disturbance to stream-riparian ecosystems in temperate zones, the effects of fire-severity on stream-riparian structure and function in Mediterranean-type systems remains less well resolved. Mediterranean ecosystems of California are characterized by high interannual variability in precipitation and susceptibility to frequent high-intensity wildfires. From 2011 to 2014, I utilized a variety of experimental designs to investigate the influence of wildfire across 70 study reaches on stream-riparian ecosystems in Yosemite National Park (YNP), located in the central Sierra Nevada, California, USA. At 12 stream reaches paired by fire-severity, I measured riparian community composition and structure, stream geomorphology, density and community composition of benthic macroinvertebrates, and density, trophic position, mercury (Hg) body loading, and reliance on aquatically-derived energy of/by spiders of the family Tetragnathidae, a common riparian spider that relies heavily on emergent aquatic insect prey. In addition, along a gradient of drainage area in two rivers, I measured the relative effects of ecosystem size, flood magnitude, productivity, and wildfire on trophic position and reliance on aquatically-derived energy of/by benthic insect predators and tetragnathid spiders. Aquatic birds like the American dipper (Cinclus mexicanus) are considered landscape integrators and are constrained by different ecological processes than aquatic organisms, therefore assessment of the trophic dynamics of aquatic-obigate birds may illuminate divergent patterns related to both fire and food-web dynamics. I estimated reliance on aquatically-derived energy and trophic position of dippers in 27 mountain streams and estimated the relative explanatory power of ecosystem size, precipitation, and wildfire as predictors of dipper trophic dynamics. Taken together, the results of my study, combined with the long period of time since fire at some study reaches, indicate support for interactions between wildfire and climate across complex spatial and temporal scales as drivers of stream-riparian ecosystem responses to wildfire.

Committee:

Mazeika Sullivan (Advisor); Amanda Rodewald (Committee Member); Desheng Liu (Committee Member)

Subjects:

Ecology; Environmental Science; Freshwater Ecology; Water Resource Management

Keywords:

stream-riparian ecosystem; food web; aquatic-terrestrial linkages; trophic position; food-chain length; Tetragnathidae; American dipper; California; Yosemite; Mediterranean climate; wildfire; disturbance; ecosystem size

Lindner, Jessica ReneeTesting nutrient limitation of the benthic biofilm in acid mine drainage remediated streams
Bachelor of Science (BS), Ohio University, 2015, Environmental and Plant Biology
Acid mine drainage (AMD), the addition of acidic and iron rich water into streams, is a common environmental problem in mineral extraction areas. As part of AMD remediation, pH is raised in an affected stream, causing iron to become immobilized in stream sediment. Iron can sorb to phosphorus, so phosphorus may inadvertently be removed during remediation. As phosphorus is an essential nutrient to algae, phosphorus limitation could prevent full biological recovery of remediated streams. If benthic algae in remediated streams are phosphorus limited, then they will have lower chlorophyll a content and biomass than algae in control streams. To test this, algae were colonized on nutrient diffusing substrata (NDS) amended with increased nitrogen, phosphorus, and nitrogen and phosphorus in remediated and control streams. The phosphorus and nitrogen acquiring enzyme activity of resulting algal communities was measured to determine nutrient limitation, increased enzyme activities indicate nutrient limitation. All biofilms regardless of stream type or nutrient treatment were limited by phosphorus, and there were no significant differences in biofilm biomasses. Chlorophyll a content from biofilms in remediated streams was significantly (P<0.01) higher in remediated streams, though chlorophyll a was also significantly (P<0.01) positively correlated with % open canopy cover and nutrient concentrations in streams. The work was supported by OU Honors Tutorial College and OU Department of Plant Biology.

Committee:

Morgan Vis (Advisor)

Subjects:

Ecology; Environmental Studies; Freshwater Ecology

Keywords:

acid mine drainage; biofilm; remediation; nutrient limitation; enzyme activity; stream ecology

Bingham, Sonia NicoleAquatic macroinvertebrate use of rootmat habitat created by eight woody riparian species
Master of Science, The Ohio State University, 2009, Environmental Science

Rootmats are an instream habitat type created by fine roots of riparian vegetation that are exposed through natural erosion at the stream bank. Previous research indicated that rootmats may be important habitats for aquatic invertebrates and may have a distinct invertebrate composition compared to other instream habitat types. The objective of this study was to examine the invertebrate communities inhabiting rootmats of eight common woody riparian species in Cuyahoga Valley National Park, Ohio (CVNP). I collected 47 rootmat samples from pools across 10 CVNP streams. Coarse particulate organic matter, root morphology, and physiochemical variables were measured to characterize the local habitat at each location. Invertebrate community indices, multivariate techniques and univariate techniques were used to investigate the role of rootmats as habitat and determine whether any associations existed between invertebrate communities and eight woody riparian species. Additionally, invertebrate communities of rootmats were compared to adjacent riffles for eight sites.

A total of 138 taxa were collected from rootmats across all woody species. Most (59%) of the taxa were gathering collectors and this suggests that fine particulate organic matter may be a dominant food source within or near rootmats. Additionally, 15% of the captures were predators, while scrapers, shredders and filtering collectors were present in similar proportions (8-9% each). Paratanytarsus dissimilis was the most abundant organism across the samples at nearly 250 organisms m-2. Other abundant taxa were Chironomidae (midges), Calopteryx maculata (damselfly), Caecidotea communis (isopod), Stenelmis sp. and Dubiraphia bivittata (riffle beetles). Invertebrate diversity, species composition and functional feeding guilds differed among certain tree species. Specifically, rootmats of two willow species (Salix interior and Salix nigra) were consistently similar to each other, and different from rootmats of Carpinus caroliniana, Fraxinus pennsylvanica, and Acer saccharum. Additionally, invertebrate species composition was different in adjacent rootmat and riffle habitats, but the habitats were similar in terms of diversity and abundance.

Committee:

Virginie Bouchard, PhD (Advisor); Charles Goebel, PhD (Committee Member); Peter Smiley, PhD (Committee Member)

Subjects:

Biology; Ecology; Environmental Science; Forestry; Freshwater Ecology

Keywords:

Cuyahoga Valley National Park; roots; rootmats; stream bank; habitat; riparian; restoration

Rowland, Freya E.Light and nutrients differentially regulate energy transfer through experimental benthic and pelagic food chains
Master of Science, Miami University, 2010, Zoology
How energy transfers through food chains is linked to food quality of the primary producers at the base of the food chain. In this study, we used a mesocosm experiment to examine how light and nutrient variation affected food chain efficiency (FCE) in an aquatic food web with benthic and pelagic food chains, and whether the FCE differences could be explained by stoichiometric food quality of primary producers. Pelagic FCE varied significantly and was highest in the treatment with the best algal stoichiometric food quality, perhaps due to carryover effects from algae to fish. Benthic FCE, however, did not vary much, despite large stoichiometric food quality differences in periphyton and only two steps in the food chain. This study is the first to examine both pelagic and benthic FCE within the same system, and highlights the importance of consumer needs in determining how food quality affects energy transfer efficiency.

Committee:

Michael Vanni, PhD (Advisor); Maria Gonzalez, PhD (Advisor); Michelle Boone, PhD (Committee Member); Craig Williamson, PhD (Committee Member)

Subjects:

Ecology; Freshwater Ecology; Zoology

Keywords:

food chain efficiency; benthic; pelagic; food quality; ecological stoichiometry

Sharp, Colleen C.R.Effects of copper and light exposure on the development and survival of the Wood Frog tadpole (Rana sylvatica)
Master of Science, University of Akron, 2008, Biology

Both concern over amphibian declines (Dunson et al., 1992; Blaustein, 1994) and the potential of amphibians as indicators (Phillips, 1990; Dunson et al., 1992; Boyer and Grue, 1995) of ecosystem health provided the impetus for this study. Utilizing amphibians as indicator species is comparable to the use of canaries in a coal mine when assessing the quality of an aquatic environment (Barinaga, 1990). Embryos, tadpoles, and adults are considered to be sensitive to environmental contaminants in part due to their unshelled eggs and permeable skins (Bridges et al., 2002; Blaustein et al., 2003; Kiesecker et al., 2004; Hogan et al., 2006). Amphibians offer a unique biphasic life cycle for studying water and land habitats as well as the interactions between the two environments. This study investigated the interaction between two human-mediated environmental changes on the development of a common North American anuran, (Rana sylvatica) the Wood Frog.

Anthropogenic changes have increased copper and sunlight in many amphibian habitats. Human disturbance often leads to a decrease in canopy cover, which thereby reduces shade for developing embryos and tadpoles of certain anuran species within the aquatic environments below (Werner and Glennemeier, 1999; Skelly et al., 2002). Water runoff from impermeable surfaces and agricultural and residential properties transport toxins and excess nutrients into bodies of water, leading to algal blooms. In ponds, a common algaecide utilized to eliminate the ensuing blooms is copper sulfate.

This work investigated the effects of copper sulfate and increased solar radiation on the developmental rate and survival of Wood Frog tadpoles in high pH ponds. pH levels in Northeastern Ohio ponds are higher (7.0-8.5; Matson et al., unpublished data, 2006) than in many other areas of Wood Frog study and research is lacking in non-lab environments at these pH levels. A field study used cattle tanks for testing the influence of increased light, increased copper, and for interactions between these environmental perturbations. Copper was a significant source of variation in measures of tadpole developmental rate and marginally significant in tadpole survival. Shade was not a significant source of variation in survival, but did significantly slow development. In addition, copper and shade interacted in their effect on developmental rate as measured by an increase in body mass in ambient copper treatments. These results are beneficial in understanding whether the use of copper sulfate is a contributor to amphibian decline.

Committee:

Francisco Moore, PhD (Advisor); Brian Bagatto, PhD (Committee Member); Timothy Matson, PhD (Committee Member); Peter Niewiarowski, PhD (Committee Member)

Subjects:

Aquaculture; Ecology; Environmental Science; Freshwater Ecology

Keywords:

Wood Frog; copper; light; amphibian; anuran; bioindicator

Zapata, Martha JSpatial and temporal variability in aquatic-terrestrial trophic linkages in a subtropical estuary
Master of Science, The Ohio State University, 2018, Environment and Natural Resources

Estuaries and coastal wetlands are highly productive ecosystems that support unique biodiversity and complex food webs. The movement of organisms among habitats is a critical facilitator of biological connectivity in estuaries, however, little attention has been directed towards biological connectivity between aquatic and terrestrial zones. Although a substantial body of research has documented aquatic insect emergence as a critical nutritional subsidy between rivers and their adjacent riparian zones that is essential to the functioning of both ecosystems, our understanding of this food-web linkage in estuaries remains unresolved.

My research aimed to characterize emergent (i.e., adult) aquatic insects and insect-facilitated subsidies to terrestrial consumers (i.e., orb-web spiders) across the Fakahatchee Strand and Ten Thousand Islands Estuary of southwestern Florida. Emergent aquatic insects and nearshore orb-weaving spiders were surveyed during the summer and winter seasons of 2015 and 2016 at nine study reaches (i.e., sites) representing upper, mid, and lower segments of the estuary, generally corresponding with freshwater, mesohaline, and polyhaline habitats, respectively. Salinity, as well as a suite of additional physicochemical parameters including dissolved oxygen, temperature, total dissolved solids, pH; nutrients (total nitrogen, nitrate, total phosphorus, phosphate); and shoreline habitat were also measured. These data were used to address the following questions: (1) How do the density, community composition, and individual traits of emergent aquatic insects vary seasonally across an estuarine salinity gradient, and how are these characteristics related to the distribution and condition of nearshore orb-weaving spiders? (2) How are trophic dynamics (aquatically-derived nutritional subsidies, trophic position) of riparian spiders associated with spatial and temporal variability in estuaries as mediated by emergent insect subsidies?

Abnormally-high rainfall induced by El Niño-Southern Oscillation (ENSO) led to salinity levels that deviated from typical winter months. Emergent insect density varied by season and estuary position (linear mixed model [LMM]: F1,37 = 8.57, P = 0.006 and F2,5.8 = 8.75, P = 0.018, respectively), but was generally higher during the winter. Overall, emergence rates were highest at mid-estuary reaches during the winter ( ± SE, 17.9 ± 5.8) and lowest at lower-estuary reaches during both the summer ( ± SE, 1.89 ± 2.81) and winter ( ± SE, 4.22 ± 1.98). Season was a strong predictor of Shannon diversity (LMM: F1,36 = 15.645, P < 0.001), Pielou’s evenness (LMM: F1,31.8 = 5.316, P = 0.028), and richness (families) of emergent insects (LMM: F1,36 = 26.353, P < 0.001) most notably at lower-estuary sites where measures were higher during the winter. Water temperature, and phosphate and total nitrogen concentrations also received support as predictors of emergence rate (R2 = 0.19, F = 5.77, P = 0.024). Community composition varied spatially across the estuarine gradient (ANOSIM: R = 0.158, P = 0.001), and showed a marginal seasonal difference only at lower-estuary habitats (ANOSIM: R= 0.1023, P = 0.061). Insect communities were largely dominated by Chironomidae, which accounted for 53-56% of variation in community composition across the estuarine gradient. Spatial and seasonal patterns in density of Dolichopodidae also contributed to the observed community differences. Mean body size of Chironomidae and Dolichopodidae were generally 180 and 400% larger, respectively, at lower-estuary habitats compared to upper-estuary counterparts. At lower-estuary reaches, emergent aquatic insects exhibited lower dispersal ability and higher prevalence of univoltinism than upper- and mid-estuary assemblages.

Orb-weaving spider density tracked emergent insects, with densities at mid-estuary reaches exceeding those of the upper- and lower-estuary, There was also a seasonal effect on orb-web density (LMM: F1,84.8 = 16.692, P < 0.0001), particularly at mid-estuary reaches where densities were higher during the winter than the summer (P < 0.0001). Estuary position strongly influenced body condition of Tetragnatha, which was 96% higher in the lower-estuary than in the upper-estuary (LMM: F2,19.50 = 11.254, P = 0.0006). Leucage body condition was strongly influenced by a season x position interaction (LMM: F2,348.31 = 2.506, P = 0.083), whereby individuals exhibited higher body condition during the winter at upper- (P = 0.046) and mid-estuary (P < 0.0001) habitats.

Bayesian mixing models using δ13C and δ15N signatures of primary producer sources and consumers showed that aquatically-derived energy (i.e., nutritional subsidies originating from epiphyton and phytoplankton) represented 0.79 to 0.99 of the diet of nearshore spiders across all study reaches and seasons. Reliance on aquatically-derived energy varied spatially (LMM: F1,174 = 358.57, P < 0.0001) and was higher overall at mid- and lower-estuary reaches than in the upper-estuary (Tukey HSD, P < 0.05). For the most common family of spiders, Tetragnathidae, reliance on aquatically-derived energy was slightly greater in winter (0.89) than summer (0.79) at FW and PH reaches (0.99 v. 0.94, respectively). Estuary position (LMM: F2,.6.31 = 57.420, P < 0.0001) and season (LMM: F1,172.94 = 128.947, P < 0.0001) also exerted strong effects on spider trophic position. Spiders occupied higher trophic positions during the summer at upper- and mid-estuary reaches (Tukey HSD, P < 0.0001), whereas trophic positions were consistently lower at lower-estuary reaches. δ13C of orb-weaving spiders trended with δ13C of Chironomidae during the summer (R2 = 0.52, F1,4 = 6.401, P = 0.065), but not during the winter (P > 0.05), suggesting that Chironomidae is an important dietary component and vector of aquatically-derived energy at least during some time periods.

Together, these findings contribute to our understanding of aquatic insect community structure and function in estuarine ecosystems. Wet-dry seasonal hydrology and ENSO events appear to drive emergent insect communities, largely via effects on salinity concentrations but also through effects on nutrients and water temperature. In addition, these results have important implications for subsidy dynamics in estuaries. In this study, spatial and temporal variability in the density and traits of emergent insects were related to nearshore spiders, and thus are likely to also mediate the distribution and trophic characteristics of a suite of other terrestrial insectivores including bats, birds, lizards and influence trophic-mediated ecosystem processes including nutrient cycling, biomagnification of contaminants, and maintenance of biodiversity. An improved understanding of seasonal subsidy dynamics in estuaries may help forecast and manage functional ecosystem responses to environmental disturbances (e.g., sea level rise). For example, artificial lighting at night (ALAN) is projected to increase in intensity alongside human population density in coastal areas. ALAN has been shown to affect emergent aquatic insect communities as well as riparian orb-weaving spiders. I conclude the thesis with a review of potential impacts that ALAN may pose in estuaries, from individual- to ecosystem-scale effects.

Committee:

Mazeika Sullivan, PhD (Advisor); Suzanne Gray, PhD (Committee Member); Lauren Pintor, PhD (Committee Member)

Subjects:

Aquatic Sciences; Ecology; Environmental Science; Freshwater Ecology

Embke, Holly SusanAssessing the Spawning Potential of Grass Carp in the Sandusky River Under Varying Conditions
Master of Science, University of Toledo, 2017, Biology (Ecology)
Invasive Grass Carp (Ctenopharyngodon idella) have been stocked for decades in the United States for vegetation control. Adults have been found in all of the Great Lakes except Lake Superior, but no self-sustaining populations have yet been identified in Great Lakes tributaries. Previous research suggested natural reproduction has occurred in the Sandusky River; hence I sampled ichthyoplankton using bongo net tows and larval light traps June through August 2015 and 2016 to determine if Grass Carp were spawning. I identified and staged eight eggs that were morphologically consistent with Grass Carp. Five eggs were confirmed as Grass Carp using quantitative PCR and DNA sequencing, while three were retained for future analysis. All eggs were collected during high-flow events, either on the day of or 1-2 days following peak flow, supporting a suggestion that high-flow conditions favor Grass Carp spawning. From my egg collection findings, I used hydraulic modeling to estimate the most probable spawning and hatching locations for these eggs. Preliminary model results suggest eggs were most likely released near the hypothesized spawning site near Fremont, Ohio at river km 21.25. Hatch locations were near the mouth of the Sandusky River at Muddy Creek Bay, with the majority of eggs likely hatching at river km 2.9. These locations will help guide future sampling efforts, inform risk assessments and aid targeted control efforts.

Committee:

Christine Mayer (Committee Co-Chair); Song Qian (Committee Co-Chair); Patrick Kocovsky (Committee Member); Seth Herbst (Committee Member)

Subjects:

Aquatic Sciences; Biology; Ecology; Environmental Science; Freshwater Ecology

Keywords:

Great Lakes; invasive species; hydraulic modeling

Dietz, Alyssa KSoil and Litter Legacy Effects of Invasive Flowering Rush (Butomus umbellatus) on Lake Erie Wetland Restoration
Master of Science (MS), Bowling Green State University, 2015, Biological Sciences
The Great Lakes region has been impacted by the invasion of over 180 different alien species. As invasives have reduced wetland habitat availability and altered community structure, managers have developed extensive eradication programs. However, even following the removal of dense monocultures, invasive plants can influence native ecosystems through long-term chemical and biological changes, known as legacy effects. My research investigates the potential for these legacy effects following the removal of Flowering Rush (Butomus umbellatus), an understudied emergent in Lake Erie wetlands. This research focuses on how legacy effects of B. umbellatus may influence restoration of native communities and investigates whether the presence of remnant stands of B. umbellatus propagules or litter alters the success of native reestablishment. A seed mix of 25 native species was sown into flats with soil from either native dominated soils, areas with formerly moderate invasions, or areas with persistent Butomus monocultures. These sown plant communities were then subjected to single and combined treatments of living B. umbellatus vegetative propagules and litter alongside unsown flats that examined the response of seedbank communities. The presence of propagules greatly reduced the growth of native seedlings developing in experimental plantings by 69%. While there was no difference in biomass between native seedlings grown in univaded soils and those from areas of B. umbellatus monocultures, native diversity and community evenness were lower. Contrary to initial predictions, B. umbellatus litter increased native biomass and taxon diversity. Planted propagules also reduced applied invasive litter decomposition. Nutrient analysis of soils from sites of monocultures had elevated levels of phosphorus and nitrogen release. This work documents specific negative impacts of this understudied invasive emergent plant on Great Lakes wetland communities. My results demonstrate the importance of controlling vegetative propagules and emphasizes their potential role in inhibiting restoration efforts that are costly and time consuming endeavors for management partners. This work also suggests that there may be possible changes to microbial communities and related ecosystem nutrient cycles once monocultures have developed. My research suggests the presence of legacy effects of B. umbellatus that alter community composition and soil conditions that warrant further investigation.

Committee:

Helen Michaels (Advisor); Enrique Gomezdelcampo (Committee Member); C. Eric Hellquist (Committee Member); Jeffrey Miner (Committee Member)

Subjects:

Biology; Ecology; Freshwater Ecology

Keywords:

Ottawa National Wildlife Refuge; B umbellatus; Great Lakes; Legacy Effects; Wetlands; Invasives; Lake Erie

Ginger, Luke JONTOGENETIC CHANGES IN THE STOICHIOMETRY OF BLUEGILL UNDER CONTRASTING LIGHT AND NUTRIENT REGIMES
Master of Science, Miami University, 2014, Zoology
Fish are important mediators of nutrient cycling, having direct effects via nitrogen (N) and phosphorus (P) excretion. The relative rates at which N and P are excreted are strongly influenced by the stoichiometry of fish bodies, the resources they consume and their growth rates. However, little is known about the stoichiometry of fish during early developmental stages, when the demand for phosphorus for bone development is likely to be great. I investigated how light and nutrients impact N and P excretion rates of fish (bluegill) during early ontogenetic development. Larval bluegills were raised in mesocosms with realistic food webs, in a factorial design with two levels of light and nutrients. Light and nutrients influenced excretion rates through effects on bone development and food quality, but light and nutrients had few effects on body stoichiometry, which was a function of age. Growth rates influence the timing of ontogenetic shifts in stoichiometry.

Committee:

Mike Vanni, Dr. (Advisor)

Subjects:

Animals; Aquatic Sciences; Developmental Biology; Ecology; Environmental Science; Freshwater Ecology; Geochemistry; Limnology; Macroecology; Water Resource Management; Wildlife Conservation; Wildlife Management; Zoology

Begley, Matthew TAssessment of the freshwater mussel community of the upper Mahoning River watershed and factors influencing diversity and abundance in small streams
Master of Science in Biology, Cleveland State University, 2015, College of Sciences and Health Professions
Freshwater mussel communities have experienced drastic declines in diversity and abundance in many streams throughout North America. Among the reasons for these declines is the human-driven alteration of the landscape, as urban and agricultural use impart many known stressors to aquatic systems. Impairments include increased sedimentation, increased pollutants, increased flood frequency and intensity, and decreased diversity and abundance of many organisms, including fish, macroinvertebrates, and mussels. Attempts to explain the abundance and diversity of mussel communities using small-scale factors such as substrate type and flow velocity provided little to no predictive power. Instead, reach-scale variables, such as stream morphology and riparian vegetation, and catchment-scale variables, such as land use, performed better as predictors of mussel diversity and abundance. In this study, surveys of mussel communities were performed in Eagle Creek in 2013 and throughout the entire upper Mahoning River watershed in 2014. Stream morphology was assessed at the sites surveyed in 2014. No published surveys exist for the mussel community of the upper Mahoning River watershed, which is a headwater system in the upper reaches of the Ohio River watershed. The Eagle Creek watershed had the highest proportion of forested land in the upper Mahoning River watershed and supported the largest and most diverse mussel community, although evidence for recruitment was limited in this stream. Across the region, abundance and species richness were strongly correlated with drainage area. Abundance and species richness decreased with increased shear stress, electrical conductivity, and agricultural and urban land use. Conductivity was also correlated with agricultural land use, and no live mussels were found where conductivity exceeded 0.9mS. Overall, the upper Mahoning River watershed had a low diversity and abundance of freshwater mussels, likely due to the intensive anthropogenic land use. Even where conditions appeared better, historic land use may have obscured the relationship between in stream conditions and mussel abundance and diversity, as some populations may have experienced greater stressors in the past than today.

Committee:

Robert Krebs, PhD (Advisor); Julie Wolin, PhD (Committee Member); Paul Doerder, PhD (Committee Member)

Subjects:

Biology; Ecology; Freshwater Ecology

Keywords:

land use; freshwater mussels; community structure; distribution; stream hydrology

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