Anthropogenic alteration of nutrient supply increases the global freshwater carbon sink
journal contributionposted on 07.05.2020, 13:13 by Nicholas John Anderson, AJ Heathcote, DR Engstrom, David Ryves, K Mills, YT Prairie, PA del Giorgio, H Bennion, S Turner, NL Rose, VJ Jones, N Solovieva, A Cook Shinneman, CE Umbanhowar, SC Fritz, D Verschuren, JE Saros, JM Russell, R Bindler, B Valero-Garcés, MB Edlund, RD Dietz, AE Myrbo
Lakes have a disproportionate effect on the global carbon (C) cycle relative to their area, mediating C transfer from land to atmosphere, and burying organic-C in their sediments. The magnitude and temporal variability of C burial is, however, poorly constrained, and the degree to which humans have influenced lake C cycling through landscape alteration has not been systematically assessed. Here, we report global and biome specific trajectories of lake C sequestration based on 516 lakes and show that some lake C burial rates (i.e., those in tropical forest and grassland biomes) have quadrupled over the last 100 years. Global lake C-sequestration (~0.12 Pg year−1) has increased by ~72 Tg year−1 since 1900, offsetting 20% of annual CO2 freshwater emissions rising to ~30% if reservoirs are included and contributing to the residual continental C sink. Nutrient availability explains ~70% of the observed increase, while rising temperatures have a minimal effect.
- Social Sciences
- Geography and Environment