Anderson N J, Heathcote A J, Engstrom D R
Department of Geography, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK.
St. Croix Watershed Research Station, Science Museum of Minnesota, 16910 152 Street North, Marine on St. Croix, MN 55047, USA.
Sci Adv. 2020 Apr 15;6(16):eaaw2145. doi: 10.1126/sciadv.aaw2145. eCollection 2020 Apr.
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) has increased by ~72 Tg year since 1900, offsetting 20% of annual CO 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.
相对于其面积而言，湖泊对全球碳（C）循环具有不成比例的影响，它介导了碳从陆地向大气的转移，并将有机碳埋藏在其沉积物中。然而，碳埋藏的规模和时间变异性受到的限制很少，而且人类通过景观改变对湖泊碳循环的影响程度尚未得到系统评估。在此，我们基于516个湖泊报告了全球和生物群落特定的湖泊碳固存轨迹，并表明在过去100年中，一些湖泊的碳埋藏率（即热带森林和草原生物群落中的那些）增长了四倍。自1900年以来，全球湖泊碳固存（约0.12Pg/年）每年增加约72Tg，抵消了淡水碳排放的20%，如果将水库包括在内，则上升至约30%，并促成了剩余的大陆碳汇。养分有效性解释了观测到的增加量的约70%，而气温上升的影响最小。
