Previous research has demonstrated the widespread occurrence of microbially mediated aerobic and anaerobic diagenesis within marine carbonate frameworks such as coral reefs. In these sedimentary systems, advective and turbulent water flow, rather than diffusion, dominates the exchange of dissolved material between the framework interstitial water and the overlying seawater. Nevertheless, diagenesis is rapid enough to result in elevated concentrations of end products such as inorganic nutrients and H2S. The overall fluxes of diagenetic end products from a reef framework to the neighboring environment will be determined. Work will be done to 1) extend the spatial scale of the interstitial water sampling at Checker Reef, Oahu to examine in detail the upper 1 m of the reef framework; 2) directly measure the advective and diffusive fluxes of diagenetic reactants and products between the reef framework and the surrounding environment at several points across the reef; 3) collect data to calibrate a hydrological model of the advection of interstitial water within the reef; 4) continue measurements of the spatial and temporal distribution or inorganic and organic diagenetic reactants/products within the reef, with particular attention to short-chain organic nitrogen compounds; and 5) use the concentration data from item 4) with the hydrological model to estimate the rates of organic and inorganic diagenetic reactions occurring within the reef framework.
