Fall 2007 Seminar Series

Tropical deltas process ~60 -70% of the global input of terrestrial carbon to the oceans.  The topset regions of these highly productive systems, as exemplified by the Gulf of Papua on the south coast of Papua New Guinea in Oceania,  often act as unsteady, suboxic batch reactors with biogeochemical properties decoupled from net accumulation of deposits.  Frequent disturbance of the bottom inhibits macrofauna, and benthic communities are typically dominated by microbial biomass.  Unsteady conditions promote suboxic diagenesis and the efficient incineration of vascular plant, aged soil, and marine planktonic C within the shallow coastal zone.  These regions are generally ignored in models of CO2 exchange with the atmosphere.  Multiple elemental cycles and properties of the sedimentary record are coupled to seabed dynamics.