Project: Collaborative Research: Organic Alkalinity: Impacts of the [OTHER] Alkalinity on Estuary and Coastal Ocean Chemistry

NSF Award Abstact:

Estuaries are bodies of water formed where rivers meet the ocean, and are important ecosystems that provide protected environments and abundant food for fish and shellfish to reproduce. Many estuary systems are under pressure by changing atmospheric and oceanic conditions, as well as impacts on the rivers that empty into them. Scientists from the University of New Hampshire and the University of South Florida propose that the total alkalinity of some coastal systems, influenced by river runoff, may contain a large fraction of organic acids that have been previously ignored and may play a role in the acid-base chemistry of the estuary. This project would focus on understanding the organic and inorganic acid-base chemistry in estuaries. The project will support a PhD student and several undergraduate students, as well as high school interns from minority communities, broadening participation in the ocean sciences. Also, the monitoring and outreach capacity of a regional wild fishery conservation group will be enhanced, allowing the public to be more fully informed on the effect of ongoing estuarine changes on fisheries.

This project will be a comparison study of two estuary-plume systems to examine the exact buffering impact of organic alkalinity on the acid-base properties of coastal systems. The Pleasant (Maine) and St. John (Canada) estuaries represent extremes of river acid-base systems, where the Pleasant is comprised mostly of organic alkalinity and the St. John has a small organic alkalinity fraction. It is hypothesized by these scientists that some coastal regions may experience organic alkalinity as the dominant alkalinity factor in the total alkalinity distribution. This would mean that organic alkalinity would be the dominant factor affecting system pH, pCO2 (partial pressure of carbon dioxide), and the saturation index of aragonite. By doing this river endmember study into organic alkalinity of these two systems, these scientists will provide the tools for the entire oceanographic community to assess the buffering capability of organic alkalinity in other coastal systems and how the systems are likely to respond to acidification.