Life Sciences Commons^™

Effects Of Global Warming On Gonadal Functions, Cellular Apoptosis, And Oxidative Stress In The American Oyster, Sarah B. Nash

Theses and Dissertations

Global warming due to climate change is predicted to intensify the heat stress in marine and coastal organisms, affecting their development, growth and reproductive functions. In this study. I analyzed gonadal development, heat shock protein 70 (HSP70), nitrotyrosine protein (NTP), dinitrophenyl (DNP) expressions, cellular apoptosis, and coelomic fluid (CF) conditions in American oyster. Oysters were placed in six aquariums and exposed to control (24°C), medium (28°C), and high (32°C) temperatures for one week. Higher temperature significantly decreased the number of eggs and sperm. CF protein concentrations also declined compared to control. In contrast, CF pH and HSP70 expression in gonad …

Applications Of Side Scan And Parametric Echosounders For Mapping Shallow Seagrass Habitats And Their Associated Organic Carbon, Austin L. Greene

Theses and Dissertations

Despite a global valuation of $1.9 trillion seagrass habitats world-wide are in decline—directly impacting the large soil carbon stocks associated with seagrasses. Many methods exist to measure the health of seagrass habitats, yet few apply to shallow coastal ecosystems. Those that do lack spatial resolution (satellite surveys) or do not provide continuous data across large areas (point-based surveys). Furthermore, carbon content of these ecosystems is largely limited to destructive and time-consuming soil core sampling. Side scan and parametric acoustics represent a unique technological opportunity to study habitat coverage and carbon content of vegetated coastal habitats (< 3 m depth). This study presents proof of concept for applications of recreational side scan and parametric sub-bottom profiling sonars in mapping both habitat coverage and organic carbon distribution in shallow seagrass habitats, and explores how these methods might be improved in future applications.

Decomposition And Nitrogen Dynamics Of Turtle Grass (Thalassia Testudinum) In A Subtropical Estuarine System, Monica Delgado

Theses and Dissertations

Seagrass beds are pivotal in the functioning of coastal ecosystems in terms of productivity, organic matter turnover and nutrient cycling. Aiming to document decay and nitrogen (N) dynamics of turtle grass (Thalassia testudinum) in a subtropical estuarine system, decomposition patterns of leaves and rhizomes were characterized and compared. Nitrogen usage during decomposition of tissues, and of live tissues and epiphytes growing on live leaves, was also quantified and compared. Stable isotope ratios allowed tracing N within the seagrass bed, following N incorporation into seagrass tissues from the surrounding media (water, sediment). Leaves had a higher N content and decomposed at …

Air-Water Gas Exchange And The Carbon Cycle Of Green Bay, Lake Michigan, James Waples

Theses and Dissertations

The purpose of this study was to constrain estimates of the kinetics of gas transfer across the air-water interface as well as quantify the net flux of carbon between southern Green Bay (1635 km²) and the atmosphere.

In 1994 and 1995, over 3500 measurements of surface water CH₄ and CO₂ were made using a continuous sample disk equilibrator. Estimates of CH₄ flux from southern Green Bay to the atmosphere based on air-water concentration gradients, shear corrected wind speeds and the U/K (wind speed/transfer coefficient) relationship of Broecker et al. (1978) agreed to within ~10% of …