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Benthic Macroinvertebrate Subsampling Effort And Taxonomic Resolution For Bioassessments Of Streams In The James River Watershed Of Virginia, Laurel Williams
Benthic Macroinvertebrate Subsampling Effort And Taxonomic Resolution For Bioassessments Of Streams In The James River Watershed Of Virginia, Laurel Williams
Theses and Dissertations
Benthic macroinvertebrate diversity influences stream food web dynamics, nutrient cycling and material exchange between the benthos and the water column. Stream bioassessment has moved to the forefront of water quality monitoring in terms of benthic macroinvertebrate diversity in the recent past. The objectives of this study were to determine optimum subsample size and level of taxonomic resolution necessary to accurately and precisely describe macroinvertebrate diversity in streams flowing in the Piedmont province of the James River watershed in Virginia. Forty-nine sampling sites were selected from streams within the Piedmont Physiographic Province of the James River watershed. Ten sites were randomly …
Characterization Of Microsatellite Loci And Pilot Population Genetic Analysis In Hickory Shad, Alosa Mediocris, Fnu Vishakha
Characterization Of Microsatellite Loci And Pilot Population Genetic Analysis In Hickory Shad, Alosa Mediocris, Fnu Vishakha
Theses and Dissertations
The hickory shad (Alosa mediocris) is a relatively understudied species of the anadromous fish sub-family Alosinae. This study, the first population genetic analysis of this species, employed 12 neutral microsatellite loci to estimate genetic diversity and population structure in tributaries of lower Chesapeake Bay, Virginia including James River and its tributaries (Appomattox and Chickahominy Rivers), Rappahannock River, and Pamunkey River. Genetic variation was extremely low. Estimates of observed heterozygosity were lower than expected heterozygosity. Significant population structure was detected among the six samples (FST = 0.093, p = 0.01). Effective population sizes were low (Ne ranged from 2 to 134). …
Variation In Sound Production Of The Blue Catfish, Ictalurus Furcatus., Zachary Ghahramani
Variation In Sound Production Of The Blue Catfish, Ictalurus Furcatus., Zachary Ghahramani
Theses and Dissertations
The blue catfish, Ictalurus furcatus, is an invasive species introduced to Virginia in 1974 and is the largest catfish in the United States. Like other Ictalurids, they are capable of producing disturbance calls via stridulation of the pectoral spine. These sounds can be made in air and water, and catfish can be preyed upon by both aerial and underwater predators. I characterized these putative distress calls by recording them in air and in the fish’s natural habitat. Sounds exhibited a wide variation in acoustic parameters relative to fish ontogeny: larger fish produced higher amplitude sounds with lower frequency bands. Sweep …
Influence Of Salinity Variations On The Desorption And Lability Of Soil Organic Carbon Associated With Tidal Freshwater Marshes, Lindsey Michelle Koren
Influence Of Salinity Variations On The Desorption And Lability Of Soil Organic Carbon Associated With Tidal Freshwater Marshes, Lindsey Michelle Koren
Theses and Dissertations
Tidal freshwater marshes (TFMs) are unique ecosystems that bridge the gap between terrestrial and aquatic ecosystems and are important in the sequestration of soil organic carbon. With the ever changing global climate, TFMs are left vulnerable to downstream effects of rising sea level and salt water intrusion due to increases in flooding by saline waters. These changes often act over large spatial and temporal scales resulting in significant impacts to local and regional environments. This multidisciplinary study assessed the amount and lability of desorbed organic carbon in tidal freshwater marsh soils from the Waccamaw River Marsh, South Carolina and Sweet …
Factors Affecting Dissolved Oxygen Metabolism In Coastal Plain Streams Of Virginia, Julie Frank
Factors Affecting Dissolved Oxygen Metabolism In Coastal Plain Streams Of Virginia, Julie Frank
Theses and Dissertations
I investigated seasonal and inter-site variation in factors influencing diel dissolved oxygen (DO) metabolism at four streams in the Virginia Coastal Plain. Data were collected monthly from January to August 2008 to characterize DO metabolism (diel DO amplitude, production, respiration), incident solar radiation (PAR), dissolved nutrients, fine benthic materials (mass, C:N, Chlα) and hydrology (discharge, water transit time, transient storage). Reach-scale metabolism estimates were determined using the one-station diurnal DO technique and transit time and transient storage were determined by conservative tracer additions. Incident solar radiation was the primary determinant of DO metabolism as streams experiencing higher light levels (Herring …