SS2.02 Biogeochemical Process at the Sediment-Water Interfaces
Date: Tuesday, June 11, 2002
Time: 3:15:00 PM
Location: Carson B
 
PorubskyWP, University of Georgia, Athens, USA, newcastl@arches.uga.edu
Weston, N, B, University of Georgia, Athens, USA, nweston@arches.uga.edu
Lee, R, Y, University of Georgia, Athens, USA, rosalynn@arches.uga.edu
Joye, S, B, University of Georgia, Athens, USA, mjoye@arches.uga.edu
 
DIEL AND SEASONAL PATTERNS OF BENTHIC FLUXES OF NUTRIENTS, GASES, AND DISSOLVED ORGANICS FROM TEMPERATE INTERTIDAL SEDIMENTS
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Sediment flux cores were used to quantify benthic fluxes of nutrients, dissolved gases, dissolved organics, and reduced constituents in temperate saltmarsh sediments collected from sites in Georgia and South Carolina. Sediment flux cores (n=2-4) were collected seasonally at each site, incubated at in situ temperatures for 72 hours, and sampled at 12 hour intervals. Light/dark incubations were performed to evaluate the impact of benthic primary production on benthic fluxes. Benthic chlorophyll concentrations and rates of gross photosynthesis (determined using microelectrodes) illustrated that these sediments were very productive. Oxygen concentrations in the overlying water decreased over the incubation and fluxes of PO4, Fe, and NOx exhibited a strong correlation to oxygen concentration. The flux of dissolved organics exhibited a seasonal pattern with increased efflux of DOC, DON, and DOP during summer. N2 and N2O fluxes showed high rates of denitrification that were correlated with photosynthesis activity and redox (oxic/anoxic) conditions. These results demonstrate the dynamic nature of materials fluxes on both large (seasonal) and small (diel) time scales and underscores the role of benthic primary producers in influencing benthic flux patterns.