Research Seminar: Melanie Cohn

The UNC-CH Department of Marine Sciences presents the interdisciplinary seminar of graduate student, Melanie Cohn. This event will be held on Monday, October 25th, at 1:30 pm. This event will be held ONLINE ONLY and it will be available online via Zoom Meeting ID 992 0501 6603

Seminar Title: Understanding Carbon Lability through Microbial Activity 

Abstract: Microbes play a critical role in the transformation and flux of nutrients from estuaries, into coastal waters, and out to the open ocean. Analytical chemical analysis of the dissolved organic carbon (DOC) pool in the marine environment is challenging due to the complex variety of organic compounds which are often in low standing stock and high flux. Indicators of microbial activity such as bacterial respiration, yield, growth rates, and transcription can be utilized to understand the lability and fate of the DOC pool. In this presentation, I will present my researching from contrasting ecosystems, the oligotrophic North Atlantic and the coastal, eutrophic Neuse River Estuary, demonstrating how indicators of microbial activity can aid in quantifying DOC pool transformations and carbon flux. Microbial respiration methods utilized on the 2021 EXPORTS cruise during the dissipation of a North Atlantic spring phytoplankton bloom quantify a major loss pathway of organic carbon through mineralization. In North Carolina at the Neuse River Estuary, changes in respiration rates and bacterial growth coupled with chemical and transcriptional analyses demonstrate a response of microbial activity to a changing carbon pool. Microbial activity indicators provide a means of detecting changes in lability of DOC stocks and quantifying fluxes, working to make bacterial drivers of the marine carbon cycle more predictable.