Land-use change, not climate, controls organic carbon burial in lakes

Abstract

Lakes are a central component of the carbon cycle, both mineralizing terrestrially derived organic matter and storing substantial amounts of organic carbon (OC) in their sediments. However, the rates and controls on OC burial by lakes remain uncertain, as do the possible effects of future global change processes. To address these issues, we derived OC burial rates in 210 Pb-dated sediment cores from 116 small Minnesota lakes that cover major climate and land-use gradients. Rates for individual lakes presently range from 7 to 127 g C m -2 yr -1 and have increased by up to a factor of 8 since Euro-American settlement (mean increase: 2.8Â). Mean pre-disturbance OC burial rates were similar (14-22 g C m -2 yr -1 ) across all land-cover categories ( prairie, mixed deciduous and boreal forest), indicating minimal effect of the regional temperature gradient (approx. 48C) on background carbon burial. The relationship between modern OC burial rates and temperature was also not significant after removal of the effect of total phosphorus. Contemporary burial rates were strongly correlated with lake-water nutrients and the extent of agricultural land cover in the catchment. Increased OC burial, documented even in relatively undisturbed boreal lake ecosystems, indicates a possible role for atmospheric nitrogen deposition. Our results suggest that globally, future land-cover change, intensification of agriculture and associated nutrient loading together with atmospheric N-deposition will enhance OC sequestration by lakes.

Effects of Climate Change on Lake Thermal Structure and Biotic Response in Northern Wilderness Lakes

“…Many of these lakes are similar to our study lakes, i.e., they are not undergoing dramatic land-use change or development [26,27]. In similar lakes where land use is changing, the effects of climate drivers are often masked [62,89]. Warming temperatures could not fully explain the increased burial rates; N deposition and cycling were suggested to be important drivers of recent OC burial trends.…”

Where Carbon Goes When Water Flows: Carbon Cycling across the Aquatic Continuum

“…OM burial rates have continued to increase in lakes and reservoirs since the industrial revolution Webb and Webb, 1988) as a result of increased land use change (Anderson et al, 2013), conversion of natural land into agricultural plots, and eutrophication in inland water bodies (Dean and Gorham, 1998;Anderson et al, 2014). In addition to enhanced burial rates, the spatial expanse of impounded waters is continuing to increase.…”

Spatial distribution and sources of organic carbon in the surface sediment of Bosten Lake, China

“…In spite of their relatively small coverage (Downing et al, 2006), lakes often receive a large amount of terrestrial materials from the watersheds (Battin et al, 2009;Anderson et al, 2013) and store a significant amount of carbon in the sediments (Ferland et al, 2012;Tranvik et al, 2009). Thus, inland lakes may play an important role in the terrestrial carbon cycle.…”