Carbon and nutrient sequestration in small impoundments: a regional study with global implications

AbstractThe rate of sequestration of carbon, nitrogen and phosphorus by lentic ecosystems informs both the global carbon budget and the remediation of eutrophication. Here we estimate carbon, nitrogen and phosphorus burial in sediments of 34 lakes in Missouri, USA, and compare them to those found in other agricultural areas as well as to global estimates. Mean sediment accumulation rates varied by orders of magnitude among study regions, with the largest values (average 6 cm y-1) in impounded systems surrounded by intensive agriculture. Rates increased with the drainage ratio and decreased with the abundance of other surface water in the catchment (e.g., farm ponds). Average organic carbon burial differed by an order of magnitude among study regions (average 150-2100 g m-2 y-1) with differences related to the drainage ratio and eutrophication. Organic carbon burial was strongly correlated with burial rates of nitrogen and phosphorus. Comparisons with a diversity of global data show that many Midwestern USA impoundments have extremely high rates of biogeochemical burial likely due to the details of agricultural cropping systems, landscape configuration, and soil characteristics.Keywords: carbonlakesnitrogenphosphorussedimentsequestrationDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsFunding for the Missouri data was provided by the Missouri Department of Natural Resources and Missouri Agricultural Experiment Station and Food & Agriculture Research Institute. Specific appreciation is extended to Anthony Thorpe and Carol Pollard.