{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/137538"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/137538","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Integrating Taxonomic Meta-Analysis and Mussel Physiology to Assess Secondary Salinization in Appalachian Headwaters and Urban Streams","abstract":"Secondary salinization from fertilizer application, mining, urbanization, and de-icing salts like sodium chloride (NaCl), is elevating chloride (Cl⁻) and sodium (Na⁺) in streams. While Cl⁻ effects on streams are well-studied, Na⁺ effects are less known. Elevated Cl⁻ levels in the environment can surpass physiological thresholds for some aquatic organisms, affecting nutrient cycling in ecosystems. A recent global review showed salinization negatively impacted freshwater animals in 78% of non-arthropod invertebrates, 68% of zooplankton, 62% of amphibians and insects, 56% of mollusks and crustaceans, and 51% of fishes. However, the diverse study designs and ionic concentrations hindered generalizable comparisons across taxa. My first objective was to expand the existing review by calculating population-level effect sizes for crustaceans, zooplankton, and mollusks. Despite the initial prediction that mollusks would exhibit the strongest negative response due to their low internal salt concentration, my findings indicated zooplankton were the most sensitive, followed by mollusks, while crustaceans exhibited more positive effects. The limited representation of unionid mussel population responses in the literature precluded their inclusion in our analysis. However, studies have noted that elevated NaCl can influence mussel filtering behavior, potentially impacting other ecosystem processes. My second objective was to examine how unionid mussel Elliptio complanata's energy storage, filtering, excretion, and biodeposition changed with elevated NaCl across a 28-day laboratory study. I anticipated reduced filtering rates, attributed to avoidance behavior (i.e. clamming-up), leading to decreased ammonium excretion and biodeposition, thereby altering nutrient cycling. I found that E. complanata energy storage remained stable across salt treatments, their excretion rate increased halfway through the experiment before declining by day 28, and clearance and biodeposition rates declined in all treatments and the control over time. My results suggest that E. complanata can live at a high-salt urban gradient due to their salt-induced avoidance behaviors, but these sublethal responses affect their ecosystem functions, thereby affecting mussel-mediated nitrogen cycling. Examining these effects is vital for understanding the ecosystem services provided by mussels amid increasing secondary salinization.","abstract_html":"Secondary salinization from fertilizer application, mining, urbanization, and de-icing salts like sodium chloride (NaCl), is elevating chloride (Cl⁻) and sodium (Na⁺) in streams. While Cl⁻ effects on streams are well-studied, Na⁺ effects are less known. Elevated Cl⁻ levels in the environment can surpass physiological thresholds for some aquatic organisms, affecting nutrient cycling in ecosystems. A recent global review showed salinization negatively impacted freshwater animals in 78% of non-arthropod invertebrates, 68% of zooplankton, 62% of amphibians and insects, 56% of mollusks and crustaceans, and 51% of fishes. However, the diverse study designs and ionic concentrations hindered generalizable comparisons across taxa. My first objective was to expand the existing review by calculating population-level effect sizes for crustaceans, zooplankton, and mollusks. Despite the initial prediction that mollusks would exhibit the strongest negative response due to their low internal salt concentration, my findings indicated zooplankton were the most sensitive, followed by mollusks, while crustaceans exhibited more positive effects. The limited representation of unionid mussel population responses in the literature precluded their inclusion in our analysis. However, studies have noted that elevated NaCl can influence mussel filtering behavior, potentially impacting other ecosystem processes. My second objective was to examine how unionid mussel Elliptio complanata's energy storage, filtering, excretion, and biodeposition changed with elevated NaCl across a 28-day laboratory study. I anticipated reduced filtering rates, attributed to avoidance behavior (i.e. clamming-up), leading to decreased ammonium excretion and biodeposition, thereby altering nutrient cycling. I found that E. complanata energy storage remained stable across salt treatments, their excretion rate increased halfway through the experiment before declining by day 28, and clearance and biodeposition rates declined in all treatments and the control over time. My results suggest that E. complanata can live at a high-salt urban gradient due to their salt-induced avoidance behaviors, but these sublethal responses affect their ecosystem functions, thereby affecting mussel-mediated nitrogen cycling. Examining these effects is vital for understanding the ecosystem services provided by mussels amid increasing secondary salinization.","abstract_has_math":false,"creators":["Mohamed, Donya Ahmed"],"institution":"Virginia Tech","degree_name":"Master of Science in Life Sciences","degree_level":"masters","degree_discipline":"Entomology","degree_department":"Entomology","school":null,"contributors":[],"advisors":[],"committee_chairs":["Entrekin, Sally"],"committee_members":["Zarnoch, Chester","Jones, Jess Walter"],"year":2025,"date_issued":"2025-08-19","date_published":"2025-08-19","updated_at":"2026-07-22T22:20:29Z","subjects":["excretion","clearance rate","filtration","biodeposition","mussel","mining","freshwater salinization","lab","experiment","chronic"],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:44423"],"render_values":[{"text":"vt_gsexam:44423","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/10919/137538","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Entrekin, Sally"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Zarnoch, Chester","Jones, Jess Walter"]},{"key":"dc:contributor.department","label":"Department","values":["Entomology"]},{"key":"dc:creator","label":"Author","values":["Mohamed, Donya Ahmed"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-08-20T08:01:09Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-08-20T08:01:09Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-08-19"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Entomology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Life Sciences"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["excretion","clearance rate","filtration","biodeposition","mussel","mining","freshwater salinization","lab","experiment","chronic"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:44423"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10919/137538"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Secondary salinization from fertilizer application, mining, urbanization, and de-icing salts like sodium chloride (NaCl), is elevating chloride (Cl⁻) and sodium (Na⁺) in streams. While Cl⁻ effects on streams are well-studied, Na⁺ effects are less known. Elevated Cl⁻ levels in the environment can surpass physiological thresholds for some aquatic organisms, affecting nutrient cycling in ecosystems. A recent global review showed salinization negatively impacted freshwater animals in 78% of non-arthropod invertebrates, 68% of zooplankton, 62% of amphibians and insects, 56% of mollusks and crustaceans, and 51% of fishes. However, the diverse study designs and ionic concentrations hindered generalizable comparisons across taxa. My first objective was to expand the existing review by calculating population-level effect sizes for crustaceans, zooplankton, and mollusks. Despite the initial prediction that mollusks would exhibit the strongest negative response due to their low internal salt concentration, my findings indicated zooplankton were the most sensitive, followed by mollusks, while crustaceans exhibited more positive effects. The limited representation of unionid mussel population responses in the literature precluded their inclusion in our analysis. However, studies have noted that elevated NaCl can influence mussel filtering behavior, potentially impacting other ecosystem processes. My second objective was to examine how unionid mussel Elliptio complanata's energy storage, filtering, excretion, and biodeposition changed with elevated NaCl across a 28-day laboratory study. I anticipated reduced filtering rates, attributed to avoidance behavior (i.e. clamming-up), leading to decreased ammonium excretion and biodeposition, thereby altering nutrient cycling. I found that E. complanata energy storage remained stable across salt treatments, their excretion rate increased halfway through the experiment before declining by day 28, and clearance and biodeposition rates declined in all treatments and the control over time. My results suggest that E. complanata can live at a high-salt urban gradient due to their salt-induced avoidance behaviors, but these sublethal responses affect their ecosystem functions, thereby affecting mussel-mediated nitrogen cycling. Examining these effects is vital for understanding the ecosystem services provided by mussels amid increasing secondary salinization."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["Human activities like farming, mining, urban development, and using salt as deicing agents on roads are increasing salt concentrations in our streams. While researchers have studied how chloride – a salt that is commonly used for road deicing – affects stream life, they know less about how sodium alone affects the ecosystem. A global review showed that too much salt can be harmful to aquatic invertebrates, including zooplankton, amphibians, insects, mollusks, crustaceans, and fishes. However, the variation in study design and ionic concentrations prevented a comparison of responses across freshwater invertebrates. My first objective was to look at how insects, mollusks, crustaceans, and zooplankton responded to increasing freshwater salinization. Despite predicting that mollusks would have the strongest negative response because of their limited osmoregulatory capacity, zooplankton were most sensitive, followed by mollusks, while some crustaceans fared even better than expected. Unfortunately, the limited representation of freshwater mussel responses caused me to exclude the taxonomic group from the analysis, although studies have shown that elevated sodium chloride can influence mussel's ability to filter water and nutrients, potentially having an effect on the nutrient cycle. My second objective was to examine how one common freshwater mussel, Elliptio complanata, responded to sodium chloride over a 28-day lab experiment. I measured how mussel energy storage, filtering, and excretion rates change across an experimental sodium chloride gradient. I found that E. complanata energy storage remained stable across salt treatments, their excretion rate increased to halfway through the experiment before declining by day 28, and filtering and bioposition rates declined over time. My results suggest that E. complanata can live at a high-salt urban gradient due to their ability to clam-up, but these sublethal responses affected their ability to eat and excrete and that altered nitrogen amounts that can degrade water quality."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science in Life Sciences"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Integrating Taxonomic Meta-Analysis and Mussel Physiology to Assess Secondary Salinization in Appalachian Headwaters and Urban Streams"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Entrekin, Sally"],"dc:contributor.committeemember":["Zarnoch, Chester","Jones, Jess Walter"],"dc:contributor.department":["Entomology"],"dc:creator":["Mohamed, Donya Ahmed"],"dc:date.accessioned":["2025-08-20T08:01:09Z"],"dc:date.available":["2025-08-20T08:01:09Z"],"dc:date.issued":["2025-08-19"],"dc:description.abstract":["Secondary salinization from fertilizer application, mining, urbanization, and de-icing salts like sodium chloride (NaCl), is elevating chloride (Cl⁻) and sodium (Na⁺) in streams. While Cl⁻ effects on streams are well-studied, Na⁺ effects are less known. Elevated Cl⁻ levels in the environment can surpass physiological thresholds for some aquatic organisms, affecting nutrient cycling in ecosystems. A recent global review showed salinization negatively impacted freshwater animals in 78% of non-arthropod invertebrates, 68% of zooplankton, 62% of amphibians and insects, 56% of mollusks and crustaceans, and 51% of fishes. However, the diverse study designs and ionic concentrations hindered generalizable comparisons across taxa. My first objective was to expand the existing review by calculating population-level effect sizes for crustaceans, zooplankton, and mollusks. Despite the initial prediction that mollusks would exhibit the strongest negative response due to their low internal salt concentration, my findings indicated zooplankton were the most sensitive, followed by mollusks, while crustaceans exhibited more positive effects. The limited representation of unionid mussel population responses in the literature precluded their inclusion in our analysis. However, studies have noted that elevated NaCl can influence mussel filtering behavior, potentially impacting other ecosystem processes. My second objective was to examine how unionid mussel Elliptio complanata's energy storage, filtering, excretion, and biodeposition changed with elevated NaCl across a 28-day laboratory study. I anticipated reduced filtering rates, attributed to avoidance behavior (i.e. clamming-up), leading to decreased ammonium excretion and biodeposition, thereby altering nutrient cycling. I found that E. complanata energy storage remained stable across salt treatments, their excretion rate increased halfway through the experiment before declining by day 28, and clearance and biodeposition rates declined in all treatments and the control over time. My results suggest that E. complanata can live at a high-salt urban gradient due to their salt-induced avoidance behaviors, but these sublethal responses affect their ecosystem functions, thereby affecting mussel-mediated nitrogen cycling. Examining these effects is vital for understanding the ecosystem services provided by mussels amid increasing secondary salinization."],"dc:description.abstractgeneral":["Human activities like farming, mining, urban development, and using salt as deicing agents on roads are increasing salt concentrations in our streams. While researchers have studied how chloride – a salt that is commonly used for road deicing – affects stream life, they know less about how sodium alone affects the ecosystem. A global review showed that too much salt can be harmful to aquatic invertebrates, including zooplankton, amphibians, insects, mollusks, crustaceans, and fishes. However, the variation in study design and ionic concentrations prevented a comparison of responses across freshwater invertebrates. My first objective was to look at how insects, mollusks, crustaceans, and zooplankton responded to increasing freshwater salinization. Despite predicting that mollusks would have the strongest negative response because of their limited osmoregulatory capacity, zooplankton were most sensitive, followed by mollusks, while some crustaceans fared even better than expected. Unfortunately, the limited representation of freshwater mussel responses caused me to exclude the taxonomic group from the analysis, although studies have shown that elevated sodium chloride can influence mussel's ability to filter water and nutrients, potentially having an effect on the nutrient cycle. My second objective was to examine how one common freshwater mussel, Elliptio complanata, responded to sodium chloride over a 28-day lab experiment. I measured how mussel energy storage, filtering, and excretion rates change across an experimental sodium chloride gradient. I found that E. complanata energy storage remained stable across salt treatments, their excretion rate increased to halfway through the experiment before declining by day 28, and filtering and bioposition rates declined over time. My results suggest that E. complanata can live at a high-salt urban gradient due to their ability to clam-up, but these sublethal responses affected their ability to eat and excrete and that altered nitrogen amounts that can degrade water quality."],"dc:description.degree":["Master of Science in Life Sciences"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:44423"],"dc:identifier.uri":["https://hdl.handle.net/10919/137538"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["excretion","clearance rate","filtration","biodeposition","mussel","mining","freshwater salinization","lab","experiment","chronic"],"dc:title":["Integrating Taxonomic Meta-Analysis and Mussel Physiology to Assess Secondary Salinization in Appalachian Headwaters and Urban Streams"],"dc:type":["Thesis"],"thesis:degree_discipline":["Entomology"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science in Life Sciences"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:29Z"}