2018 Hurricane Season: RAPID: Associated Priming of Carbon in the Albemarle-Pamlico Estuarine System (APES), the Mid-Atlantic Bight and Gulf Stream

In the early fall of 2018, two Atlantic hurricanes (Florence and Michael) deposited substantial amounts of rainfall in North Carolina. The Albemarle-Pamlico Estuarine System (APES), which was impacted by these storms, is the second largest estuary in the United States, receiving freshwater from the Coastal Plain region of North Carolina and bounded on its seaward side by the Outer Banks (OBX). The exchange of water and suspended materials between the APES and the Atlantic Ocean occurs through three inlets (Oregon, Hatteras, and Ocracoke Inlets). This proposed research explores the overarching hypothesis that extreme precipitation from the 2018 Hurricane Season flushed land-derived organic material and microbes into the APES and that material will be exported into the North Atlantic through the OBX inlets, and impact coastal ocean ecosystems. The project will support a graduate student and two undergraduates. The investigators will present a summary of this research and synopsis of the impacts from the 2018 Hurricane Season to the OBX coastal community through the 'Science on the Sound' presentation series at the Coastal Studies Institute.

The investigators propose two research questions to address their hypothesis: 1) will the pulse of the terrigenous dissolved organic matter and microbes from Florence and Michael change the regional Gulf Stream from a net sink to a net source of carbon dioxide to the atmosphere, and 2) will deposition of this elevated organic material and nutrients to the seabed seaward of the inlets, promote anaerobic and fermentation processes that will lead to algal blooms in surface waters adjacent to the Gulf Stream? Because marine dissolved organic matter is a highly complex and polydisperse mixture of different compounds, its priming and biodegradation resulting from the storms, even at rudimentary levels, may significantly affect coastal carbon cycling.

Large uncertainties exist in the regional carbon budgets of North America. Intense rain events (as defined by the upper 0.3% of daily rain events) and Category 4 and 5 Atlantic hurricanes are predicted to increase in frequency in extratropical regions, globally. Also, the erosion and entrainment of the substantial amounts of land-derived organic matter, nutrients, and microbes, collectively contribute to broad spatial and temporal uncertainties in regional carbon budgets. This study will provide data reducing these uncertainties in the Atlantic seaboard, in an area adjacent to the Gulf Stream.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.