Falter, J. L. University of Hawaii, jfalter@soest.hawaii.edu
Sansone, F. L. University of Hawaii, sansone@soest.hawaii.edu

 
FACTORS CONTROLLING PORE WATER GEOCHEMISTRY AND REDOX STRUCTURE WITHIN A WAVE-DRIVEN SEDIMENT
 
Waves propagating across the shallow and permeable sediments of Checker Reef, Oahu, Hawai`i, drive the bulk mixing and transport of interstitial water. The impact of varying sediment permeability and hydrodynamic conditions on the spatial and temporal distribution of dissolved oxygen and inorganic nitrogen was examined. Dissolved oxygen, nitrate, nitrite, nitrous oxide, and ammonium concentrations were measured in pore waters taken from the top 70 cm of sediments at two sites on the reef. Oxygen penetration was typically 35-50 cm deep. Depth-integrated oxygen concentration was generally highest under more energetic wave conditions and in sediments with greater depth-integrated permeability. The observed geochemical response of the sediments to a large wave event revealed a non-steady state behavior which was most likely due to the deposition of particulate organic matter durring the event. Spatial and temporal trends in pore water composition and redox structure are attributed mainly to differences in the delivery rates of organic matter and electron acceptors. These differences could result from the partial decoupling of the solute and particulate transport dynamics operating within the sediments.
 
Day: Wednesday, Feb. 3
Time: 12:15 - 12:30pm
Location: Eldorado Hotel
 
Code: SS03WE1215E