Benthic Fluxes in Long Island Sound
This project focuses on quantifying benthic-pelagic coupling in Long Island Sound. Benthic-pelagic coupling is critical to the ecological functioning of a system as surface column primary production fuels benthic communities which in turn support rich food webs. However, anthropogenic activities at a local (nutrient loading) and regional/global scale (global warming) can alter these benthic-pelagic processes. Like many ecosystems, Long Island Sound has been heavily fertilized leading to widespread hypoxia, most predominant in the western sound. Despite a decrease in riverine nutrient loading, low oxygen conditions persist in Long Island Sound. These low oxygen conditions are likely due to a combination of the long-term effects of cultural eutrophication and subsequent storage of carbon in the sediment as well as global warming. Benthic-pelagic coupling is an important characteristic of coastal systems and understanding the linkages between water column productivity and benthic metabolism is a necessary step in determining the ecological status of Long Island Sound (LIS). Relevant to this project is the process of denitrification. The process of denitrification is a form of anaerobic respiration that transforms nitrate, a biologically available form of nitrogen to dinitrogen gas, a form of nitrogen that is biologically inactive for most organisms. Despite the importance of denitrification, we know of only two studies on denitrification in Long Island Sound; one was based on a stoichiometric calculation almost 30 years ago, and the other one measured denitrification rates at two stations in central LIS in 2001. Thus, these measurements are not representative of actual denitrification rates within LIS. This project addresses the lack of data by directly measuring denitrification rates in LIS over a seasonal cycle, therefore, providing the missing information for the LIS N budget.
The denitrification measurements and other data we collect will be directly applicable not only for LIS nutrient budgets but also for LIS water quality models. Specifically, we will share the data collected in this study with Hydroqual for their System Wide Eutrophication Model (SWEM). SWEM is designed to provide mechanistic information on LIS ecosystem processes to water quality and natural resource managers with the goal of assisting mitigation efforts to improve overall LIS water quality.
Our primary objectives are:
The denitrification measurements and other data we collect will be directly applicable not only for LIS nutrient budgets but also for LIS water quality models. Specifically, we will share the data collected in this study with Hydroqual for their System Wide Eutrophication Model (SWEM). SWEM is designed to provide mechanistic information on LIS ecosystem processes to water quality and natural resource managers with the goal of assisting mitigation efforts to improve overall LIS water quality.
Our primary objectives are:
- Quantify benthic metabolism at five stations in Long Island Sound by measuring seasonal rates of sediment oxygen demand, benthic inorganic nutrients (nitrogen, phosphorus, and silicates), and net denitrification rates along with sediment characteristics and porewater characteristics (dissolved oxygen, inorganic nutrient and, hydrogen sulfide profiles).
- Synthesize existing data on SOD and sediment nutrient fluxes to determine if benthic-pelagic coupling has changed in LIS as it appears to have changed in Narragansett Bay.
Special thanks to Isabel Sánchez-Viruet for helping put this webpage together.