Cross-Scale Drivers of the Reciprocal Impacts Among Freshwater Mussels, Hydrology, and Floodplains on River Biogeochemistry
type: CreativeWork
description: Rivers integrate physical, chemical, and biological processes that occur within the watershed. To characterize the functional role of animal species in shaping biogeochemical cycles and resource patterns, therefore, it is necessary to account for variation in watershed features and hydrologic conditions. Freshwater mussels (Family: Unionidae) provide a valuable model system for examining the influence that species have on biogeochemical cycles and resource use because they are functionally diverse and form dense and species-rich aggregations in rivers. I focus on the Sipsey River (Alabama, USA), an undammed floodplain-river system with extensive mussel aggregations that offers an ideal setting to assess how watershed features and hydrologic conditions in conjunction with diverse and abundant biological communities shape organic matter and nutrient dynamics. In Chapter 1, I measured the biogeochemical metrics of spatial persistence, temporal synchrony, and leverage to infer how a floodplain wetland complex and variation in hydrologic conditions influence material storage and fluxes. Here, I reveal that organic matter and nutrient patterns were variably determined by processes occurring across spatial scales and by the interplay among flow conditions, floodplain-river connectivity, and the wetland complex. In Chapter 2, I combined scanning electron microscopy with stable isotope analysis and found that phylogenetic relatedness and interspecific variation in gill morphology were important factors that influenced food resource partitioning among species, while intraspecific variation in gill morphology likely constrained the range of food items that were ingested by members of a population. In Chapter 3, I performed a series of in situ benthic chamber incubation experiments and demonstrated that four functionally distinct mussel species influenced sediment ammonium and orthophosphate fluxes through their excretion, while their effects on microbial denitrification pathwa…
abstract: Rivers integrate physical, chemical, and biological processes that occur within the watershed. To characterize the functional role of animal species in shaping biogeochemical cycles and resource patterns, therefore, it is necessary to account for variation in watershed features and hydrologic conditions. Freshwater mussels (Family: Unionidae) provide a valuable model system for examining the influence that species have on biogeochemical cycles and resource use because they are functionally diverse and form dense and species-rich aggregations in rivers. I focus on the Sipsey River (Alabama, USA), an undammed floodplain-river system with extensive mussel aggregations that offers an ideal setting to assess how watershed features and hydrologic conditions in conjunction with diverse and abundant biological communities shape organic matter and nutrient dynamics. In Chapter 1, I measured the biogeochemical metrics of spatial persistence, temporal synchrony, and leverage to infer how a floodplain wetland complex and variation in hydrologic conditions influence material storage and fluxes. Here, I reveal that organic matter and nutrient patterns were variably determined by processes occurring across spatial scales and by the interplay among flow conditions, floodplain-river connectivity, and the wetland complex. In Chapter 2, I combined scanning electron microscopy with stable isotope analysis and found that phylogenetic relatedness and interspecific variation in gill morphology were important factors that influenced food resource partitioning among species, while intraspecific variation in gill morphology likely constrained the range of food items that were ingested by members of a population. In Chapter 3, I performed a series of in situ benthic chamber incubation experiments and demonstrated that four functionally distinct mussel species influenced sediment ammonium and orthophosphate fluxes through their excretion, while their effects on microbial denitrification pathwa…
author: Lodato, Matthew
language: en_US
language: English
keywords: Ecophysiology, Environmental heterogeneity, Functional traits, Organic matter and nutrient cycling, Resource partitioning, Zoogeochemistry
date published: 2025
date modified: 2026-07-27T18:44:22Z
provider: University of Alabama
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Alabama Libraries