Knauss Lecture Series, This Thursday 12-1pm EDT

The Knauss Lecture Series features current 2013 Sea Grant Knauss fellows.
Talks are held on the third Thursday of every month. All are welcome to attend.

This month’s talk will be held in Silver Spring, MD:

12-1 PM Thursday, September 19, 2013
NOAA Central Library, 2nd Floor, SSMC3
Remote access at http://www.lib.noaa.gov/.

 Carrie Givens, USFWS Branch of Aquatic Invasive Species
A Fish Tale: Comparison of the gut microbiome of 12 finfish and 3 shark species

givens

The fish gut contains a significant bacterial population that can influence fish health and physiology. Elevated concentrations of certain bacteria certain bacteria in the gut when compared to surrounding water suggest that the fish gut provides a unique niche for a select, but diverse group of bacteria. We used 454-pyrosequencing to survey the 16S rRNA ribotypes in the gut microbiomes of 12 finfish and 3 shark species, selected to encompass a wide range of lifestyles. Each species had a core gut microbiome; however, no individual ribotype was present among all species suggesting that the gut microflora community is adapted to the autecological properties and physiological conditions of each species. Results from manipulation experiments indicate that environmental variables can further affect the gut microbiome composition. We also found that the fish gut can serve as reservoir for the potential pathogens Vibrio vulnificus and V. parahaemolyticus. Fish naturally expel this gut microflora that can then be transferred to other environmental reservoirs, implicating fish in the persistence and dispersal of these potential pathogens.

Jennifer Bosch, OAR Laboratories and Cooperative Institutes/Science Advisory Board
Old Data, New Tricks: A new analysis of Chesapeake Bay Benthic Monitoring Program

bosch

An increase in hypoxia is an environmental stressor associated with eutrophic environments that can shift benthic community structures. Chesapeake Bay is a eutrophic estuary where seasonal hypoxia has been increasing since the early 1950’s. Utilizing the large dataset of macrofaunal abundance collected by the Chesapeake Bay Benthic Monitoring Program, In conjunction with concurrent measures of environmental parameters, this study examines how environmental conditions regulate the densities of opportunistic polychaetes in this estuarine system. This study supports previous work indicating a shift in the dominant polychaete community to one made up of species known to be extremely adaptable to stressful conditions like hypoxia. Our analysis further shows that the magnitude of these polychaetes response to hypoxia is species specific and dissolved oxygen is the “master variable” controlling long-term trends in this community.

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