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

这项工作的动机是观察到内陆和沿海水域陆地溶解有机碳(TDOC)的消耗量比之前认为的要高。促进土壤和植物凋落物中TDOC消耗的一个可能机制是“引发效应”，这一效应已在土壤中得到证实，但在水生系统中尚未得到证实。在土壤中的启动效应在于土壤中活性有机质的加入增加了土壤矿化的速度。支持者想要调查启动效应是否是水生系统的普遍现象，这将影响水生和陆地生态系统的二氧化碳排放，并影响其营养循环。他们的工作假设是，从有效溶解有机碳(ADOC)中提取的启动底物的可用性将促进微生物对TDOC的消耗，从而产生使用化学分析和微观实验可检测到的效果。因此，这项研究将考察在巴吞鲁日采集的密西西比州水域中TDOC的微生物利用情况，在那里，ADOC中溶解的不稳定底物与TDOC混合。确定启动效应是否影响水生系统的碳循环过程，从而影响大气中的碳浓度和向海洋输送碳，对全球碳收支和作出预测至关重要。私人投资机构希望将这些发现纳入美国碳循环计划。本科生将参与这项研究。

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.