Novus member Rebecca Barnes (Colorado College) and colleagues recently published an article in Nature Geoscience assessing radiocarbon age of dissolved organic carbon (DOC) in 135 watersheds throughout the globe. DOC ages were compared to land cover, human population, and environmental variables of the surrounding watershed. The study found that age of DOC in rivers increased with increasing human impact on the watershed, and with decreases in annual precipitation, such that 3-9% of the total export of DOC from land to river systems is aged carbon reintroduced to the modern carbon cycle via anthropogenic disturbance of the watershed landscape.
Butman, DE, HF Wilson, RT Barnes, MA Xenopoulos, PA Raymond (2015) Increased mobilization of aged carbon to rivers by human disturbance. Nature Geoscience, 8: 112-116