In Biowater’s Module 2, researchers are investigating the cycles of nutrients, carbon and water, and how these are affected by land use and climate change. A new paper (open access) examines the impact of global change on carbon cycles in a small, forested catchment. The paper gives the results of 30 years of measurements, as well as sediment dating and modeling, of a small humic lake and its catchment in southeast Norway. The percentage of dissolved organic carbon (DOC) retained in the lake catchment declined in years with high precipitation, due to lower water residence times. At the same time, lateral DOC fluxes increased. DOC that is retained in the lake is likely returned to the atmosphere as CO₂, suggesting that in a wetter climate, small northern lakes will, on balance, function more as pipes than as chimneys.

de Wit, H. A., Couture, R.-M., Jackson-Blake, L. Futter, M. N., Valinia, S., Austnes, K.,  Guerrero, J.-L., Lin, Y.  2018. Pipes or chimneys? For carbon cycling in small boreal lakes, precipitation matters most. Limnology and Oceanography Letters 00, 2018.

(Photo: Heleen de Wit)