Patterns and drivers of change in organic carbon burial across a diverse landscape: Insights from 116 Minnesota lakes

摘要: Lakes may store globally significant quantities of organic carbon (OC) in their sediments, but the extent to which burial rates vary across space and time is not well described. Using 210Pb-dated sediment cores, we explored patterns OC 116 lakes spanning several ecoregions land use regimes Minnesota, USA during past 150–200 years. Rates for individual (across all periods) range from 3 204 g C m−2 yr−1 (median 33 g m−2 yr−1) show strong geographic separation accordance with degree catchment disturbance nutrient enrichment. Climate basin morphometry exercise subordinate control over patterns, diagenetic gradients introduce little bias estimated temporal trends. Median agricultural exceed urban have increased fourfold since Euro-American settlement. The greatest increase occurred prior widespread adoption industrial fertilizers, an era clearance farmland expansion. Northern boreal lakes, impacted by historical logging limited cottage development yet comparatively undisturbed human activity, bury at 3X lower than exhibit much smaller increases burial. Scaling up modern estimates entire state, find that Minnesota annually 0.40 Tg equal 1.5% annual statewide CO2 emissions fossil fuel combustion. During period settlement (circa 1860–2000), cumulative amounted 36 C, 40% can be attributed anthropogenic enhancement.