Seasonal changes in the age and structure of dissolved organic carbon in Siberian rivers and streams

Northern latitude rivers contain the highest concentrations of dissolved organic carbon found in rivers worldwide and represent an important term in northern latitude carbon budgets.

Several studies, using data collected during late summer and early fall, indicate that dissolved organic carbon in Arctic rivers originates from carbon deposited in the past few decades. Little information exists, however, on the seasonal pattern of the dissolved organic carbon's age in these regions. Neff et al. studied Siberian rivers and streams during 2003, their observation period including winter and the spring floods. Through radiocarbon measurements, they discovered that the bulk of dissolved organic carbon during winter and spring was modern. By September 2003, however, radiocarbon ages had increased, indicating that carbon from old deposits of soils was being mobilized. Based on their findings, the authors note that, while the annual flux of dissolved organic carbon is most affected by what happens early in the growing season, the late season increase in dissolved organic carbon's age indicates the vulnerability of old carbon stocks to leaching and carbon loss in this region.

By American Geophysical Union