Project Title: Quantifying Coastal Ocean Acidification Impacts on Estuarine Nitrogen Removal

Date: 6/2019-6/2020

Principal Investigator(s): Robinson Fulweiler

Affiliations: Boston University

Summary: Ocean acidification in estuarine systems is expected to influence the biogeochemical cycling of nitrogen, a nutrient necessary for life. In estuarine systems, sediment denitrification is a natural microbial process that removes excess nitrogen and helps decrease the negative impacts of eutrophication. Evidence shows that sediment microbial communities that play a role in regulating denitrification are correlated with pH. For example, as pH decreases, the denitrification efficiency also decreases. This incomplete denitrification can lead to  an increased production of nitrous oxide, a potent greenhouse gas that is 300 times more powerful that carbon dioxide. Yet, the impact of pH on marine sediment communities in general, and denitrifies in particular, has largely gone unexplored. In this study we will assess the impact of coastal acidification on sediment denitrification.

To address this topic we will (1) characterize the potentially active sediment microbial community under different pH regimes. (2) Couple the rates of denitrification to the key functional genes of the denitrifying community. (3) Experimentally alter the water column pH to test coastal acidification impacts on sediment denitrification processes and the active microbial community.