Collaborative Research: The role of priming in microbial utilization of terrestrially-derived dissolved organic carbon: a proof of concept

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The motivation for this work is the observation of higher than previously thought consumption of terrestrial dissolved organic carbon (TDOC) in inland and coastal waters. One possible mechanism contributing to enhancing consumption of TDOC from soil and plant litter is the "priming effect," which has been demonstrated for soil but not in aquatic systems. The priming effect in soils consists in an increase in the rate of soil mineralization by the addition of labile organic matter. The proponents want to investigate if the priming effect is a general phenomenon of aquatic systems, which would influence the CO2 emissions of both aquatic and terrestrial ecosystems, and affect their nutrient cycles. Their working hypothesis is that microbial consumption of TDOC will be enhanced by the availability of priming substrates derived from available dissolved organic carbon (ADOC), resulting in detectable effects using chemical assays and microcosm experiments. Thus, this study will examine microbial utilization of TDOC in Mississippi waters collected at Baton Rouge where dissolved labile substrates from ADOC mix with TDOC. Determining whether the priming effect affects the process of carbon cycling in aquatic systems and thereby atmospheric C concentrations and the delivery of C to the oceans is of outmost importance for the global carbon budget and making predictions. The PIs want to insert the findings into the US Carbon Cycle Plan. Undergraduate students will be involved in the research.