Life Sciences Commons^™

Plastics And Microplastics As Vectors For Bacteria And Human Pathogens, Amanda Lee Laverty

OES Theses and Dissertations

Since plastics degrade very slowly, they remain in the environment on much longer timescales than most natural substrates and can thus provide a novel habitat for colonization by bacterial communities. The full spectrum of relationships between plastics and bacteria, however, is little understood. The objective of this study was to examine marine plastic pollution as a substrate for bacteria, with particular focus on Vibrio spp., including the human pathogens, Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus.

Colonization experiments were set up in a tributary of the lower Chesapeake Bay to follow Vibrio spp. colonization and …

Predation Thresholds In Marine Microbial Communities Applied To Environments With Low Prey Abundances, Bonnie Bailey

OES Theses and Dissertations

Prokaryotes (Bacteria and Archaea) comprise the largest component of biomass in the world's oceans. Their abundances are controlled by resource availability, viral infections and protist grazing. Many pico- and nano-eukaryotic predators grow almost as quickly as their prey, and greatly increase in numbers as soon as their prey do, leading in tum to depletion in prokaryotes. It is still unclear however, as to what extent microbial predators are able to feed in low prey environments, most prominently in the largest biome on Earth, the deep sea (below l 000 m depth). It has been hypothesized that in low prey environments, …

Interactions Between Phytoplankton And Bacteria In The Uptake Of Organic Compounds, Andrea Michel Rocha

OES Theses and Dissertations

The most common methods for estimating bacterial productivity are [³H]-leucine and [³H]-thymidine incorporation. Uptake of these compounds has been attributed primarily to bacteria; however, because dissolved organic nitrogen may be an important N source for some phytoplankton, the use of these compounds to estimate bacterial productivity needs to be reexamined. In order to ascertain whether phytoplankton could compete with bacteria on relevant timescales and thereby bias bacterial productivity estimates in estuaries, I examined the ability of cultured phytoplankton and size-fractionated natural populations to take up leucine and thymidine in systems seasonally dominated by phytoplankton mixotrophs. In …