This research investigated changes in sediment oxygen consumption (SOC) as a factor of variations in organic carbon loading. This was accomplished through modification of a traditional benthic incubation chamber to create a benthic oxystat. The modification consisted of adding silicone tubing to maintain near ambient oxygen concentrations within the chamber. Various amounts of organic carbon in the form of ground catfish feed were introduced into the oxystat with the expectation that SOC would increase proportionately. The initial hypothesis was that most of the added carbon would be converted to CO2.

The bulk of this research consisted of 15 experiments in which total organic carbon (TOC) amounts equivalent to an average value of 2.2, 2.3, and 4.3 g C m-2 were added to the oxystat. Increases in O2 consumption over background values were measured over an average period of 195.8 hours. The amount of carbon metabolized into CO2 was estimated by stoichiometric conversion of oxygen consumption rates. The oxygen consumption curves indicated a rapid increase immediately following carbon addition with a maximum consumption between 48 to 72 hours. Afterwards, the SOC rates gradually declined but never returned to ambient levels. SOC increased proportionately to the amount of carbon added, but the amount of carbon metabolized to CO2 averaged only 19.7 %. This unexpected value forced adjustment of the original hypothesis to consider other carbon partition components. The most obvious was biomass. Benthic biomass was quantified by determining the change in biomass of the principal functional groups of the community (bacteria, meiofauna, macrofauna). Changes in biomass values were compared to ambient values prior to additions. Total biomass was shown to increase in a linear fashion with the average increase equivalent to 7.4 % of the added carbon.

As a result of these experiments, it was possible to quantify the fate of 27 % of the added carbon after 195.8 hours. The remaining carbon could be accounted for by continued long-term partitioning into CO2 and biomass. Mathematical models for predicting the ecosytem response to increased carbon loads were produced using Excel spreadsheets. The resulting models were then adjusted for temperature variations.