Organic Carbon Burial Rates in Artificial Ponds Driven by Age and Catchment Land Cover

Artificial ponds are globally abundant, and their high rates of biogeochemical cycling make them significant components of regional and global aquatic carbon budgets. Yet, the extent to which artificial ponds are net sources or sinks of atmospheric carbon is unclear, hampered by limited data on burial rates of organic carbon (OC). Considering that humans construct ponds for a myriad of purposes, quantifying OC burial rates and drivers is important to constrain anthropogenic carbon budgets from inland waters. Here, we quantified OC burial rates for 27 artificial ponds across a forested to agricultural land cover gradient in central New York State (USA) and explored drivers of variability in OC burial rates. Across all ponds, OC burial rates averaged 69.6 ± 9.0 (SE) g OC m−2 yr−1 and ranged between 12.3 and 191.3 g OC m−2 yr−1. Rates of OC burial decreased with pond age and catchment forest cover and increased with nitrogen inputs, with multiple regression models explaining 46–53% of the variance. Younger ponds had higher OC burial rates, likely due to greater inputs of terrestrial OC from erosion that decreased as ponds aged. Land cover also shaped OC burial rates, with burial rates decreasing with increasing forest cover. In agricultural catchments, ponds with greater sheltering from adjacent vegetation had reduced nutrient loads, which can lower OC burial rates relative to more exposed agricultural ponds. Ultimately, understanding the range and variability of OC burial rates in artificial ponds can improve upscaled estimates of OC burial and inform management practices.