Biology Honors Presentations. Wednesday, May 1, 4:30 p.m.Stafford Auditorium. Christopher Mealey presents “Climate Change Effects on Marine Ecosystems”
Chris Mealey will present his honors thesis research, including work from the Chesapeake Bay (USA) and Moreton Bay (Australia) this week. Chris arrived in our lab four years ago and also conducted research at the School for Field Studies – Turks and Caicos site on invasive lionfish and at the University of Queensland as a part of our Global Scholars Program. Some of his work was published in the journal PLoS ONE in 2012 and he will be attending the graduate program in marine biology at the University of Charleston in the fall. Come hear about his work on Wendesday!
NEW UPDATE: Chris was awarded departmental honors for his thesis “Impacts of Ocean Acidification on the Polyphenolics of Seagrasses” on May 14, 2013. Congratulations Chris!
Abstract
Atmospheric carbon dioxide (CO2) has increased by about 40% since the Industrial Revolution, with current levels residing around 395ppm. A portion of this excess CO2 is absorbed by the oceans resulting in the increase of H+ and carbonic acid concentrations, as well as a corresponding reduction in mean pH. This phenomenon is termed ‘ocean acidification’ (OA). Multiple studies demonstrate a decline in calcification of many marine organisms as a result of OA, but greater photosynthetic productivity in algae and seagrasses has also been reported. However, little is known regarding the effects of OA on the chemical defenses produced by these marine angiosperms. Three forms of CO2 enrichment were utilized in this study to observe the effects OA may have on secondary metabolite accumulation in four species of seagrass. These include a Free Ocean Carbon Enrichment (F.O.C.E.) system – Severn River, MD (USA), a natural volcanic vent – Vulcano (Italy), and the naturally acidified Myora Springs – North Stradbroke Island (AUS). Additionally, herbivory tests examined preferences of juvenile black rabbitfish on eelgrass grown in low and normal pH regions near the naturally acidified Myora Spring (AUS). Phenolic acids, the main chemical defenses of these species, were identified and measured via HPLC, whereas more complex tannin concentrations were measured by colorimetry. The results of this experiment observed a significant decrease, about 60% in some instances, in the production of these secondary metabolites corresponding to a decrease in average oceanic pH and an increase in pCO2 concentrations. The reduction in the accumulation of these chemical defenses within the observed seagrasses implies a greater susceptibility to herbivory and harmful pathogens, which reveals location dependent impacts of OA on marine plants.
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