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SGD DISTRIBUTION ON THE HAWAIIAN ISLANDS – SPATIAL AND LONG-TERM TRENDS AND THEIR BIOGEOCHEMICAL IMPLICATIONS

The Hawaiian Islands capture a range of geologic, land-use, climate, and population gradients. We study submarine groundwater discharge in multiple watersheds across these gradients. In this context we have been investigating the significance of SGD as a terrestrial nutrient pathway to the ocean and the source of the nutrients it carries to the coastal zone. I will present selected studies where variability of groundwater fluxes were monitored on longer time scales and were compared to stream fluxes. Our analysis of watersheds, some of which host the largest coral reefs on the islands, revealed that SGD in the form of total (fresh+brackish) groundwater discharge was 1-4 times larger than surface inputs. Corresponding dissolved inorganic nutrient fluxes were also dominated by SGD and their effect on the coastal ecosystem was evaluated. Depending on the coastal settings, such as water residence times, SGD-derived nutrient removal in the coastal zone varied from negligible to as much as 80 %. These findings suggest that along many shorelines on the islands SGD is not negligible from hydrological and geochemical perspective.

Author

Dulai, H., Department of Geology and Geophyscis University of Hawaii, USA, hdulaiov@hawaii.edu

Details

Poster presentation

Session #:065
Date: 02/27/2017
Time: 11:00 - 12:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 520