Estuarine air-Sea CO2 Fluxes: Evaluating the Impact of Climatological Drivers Spanning Multiple Temporal Scales using Ships-of-Opportunity and Remote Sensing

OCE-0726989

Estuaries are among the most productive and dynamic aquatic ecosystems on Earth. Because they cover extensive areas of coastlines worldwide, estuaries play key roles in regional and global C cycling. However, estuarine air-sea CO2 fluxes, which represent the sum of the major metabolic processes in the estuary, are strongly influenced by intra- and interannual variability in climatological/hydrological forcings such as hurricane events. Because of limited spatial-temporal sampling resolution, previous studies have not been able to determine the impact of these different scales of variability on estuarine air-sea CO2 fluxes. In this research, an interdisciplinary team from the University of North Carolina at Chapel Hill and Oregon State University has been assembled to quantify air-sea CO2 fluxes in the nation's 2nd largest estuary, and to evaluate and quantify environmental controls upon those fluxes. North Carolina's Neuse River-Pamlico Sound estuarine system (NRE-PS) is downstream of rapidly expanding urban and agricultural activities and has had five category 2 or higher hurricanes make landfall in its watershed in the past decade. Additionally, the system's microtidal nature and long water residence time (>2 mo) make it ideal for a study on estuarine air-sea CO2 fluxes. The NRE-PS has the added advantage of ongoing, spatially and temporally intense, long-term observational programs that will serve as sources of complementary environmental data; the Neuse River Modeling and Monitoring Program (ModMon), and a ferry-based continuous monitoring program (FerryMon).

Robust evaluation of NRE-PS air-sea CO2 fluxes will be accomplished by outfitting a small research boat and three N.C. Dept. of Transportation ferries with CO2 partial pressure (pCO2) sensors, thereby allowing for year-round, high spatial-temporal resolution characterization of surface p CO2. Remotely-sensed (every 3 d) surface biogeochemical data, generated by an ongoing collaborative project with researchers at the U.S. EPA, will also be available. In addition to addressing air-sea fluxes, the data from this project will enhance an existing mechanistic biogeochemical estuarine model that is used to investigate linkages between nutrient and hydrologic forcings, and system wide C and O2 dynamics. This effort, in conjunction with synthesis of data collected during the other parallel monitoring programs, will be invaluable for assessing the ecosystem response to extreme climatological events such as droughts and a predicted rise in Atlantic hurricane activity.

In terms of broader impacts, the NRE-PS exemplifies the classic symptoms of human and climatological perturbations impacting the coastal margin and so this project's results have the potential to apply to productive estuarine ecosystems worldwide. This project will also provide diverse educational opportunities for post-doctoral researchers, graduate students, and undergraduate students, who will be actively engaged in field and laboratory components and encouraged to develop independent research projects. The NSF-supported Summer Pre-graduate Research Experience Program (SPGRE) at UNC-CH and regional universities educating predominantly under-represented and minority groups will provide students for summer internships. Finally, high school students and teachers will be employed as interns during the summer field season, giving them a range of newfound experiences and knowledge to bring back to the classroom.