SIMULATION OF CARBON CYCLING IN A RIVER BASIN IN FINLAND

The intricate interplay between eutrophication and carbon accumulation in aquatic ecosystems remains a subject of limited understanding, posing challenges for effective river basin management. In this study, the operational, national-scale nutrient loading model, WSFS-Vemala (Vemala), simulating 67500 lakes and used for river basin management planning in Finland, was developed to include total carbon cycling in the aquatic ecosystem. Vemala v3 simulates past, present and future nutrient leaching and transport on land, as well as in rivers and lakes. A field scale model is applied for phosphorus and nitrogen terrestrial leaching from agricultural areas. The total organic carbon (TOC) and total inorganic carbon (TIC) leaching are defined by soil types and land uses. The model includes point loads, urban runoff, atmospheric deposition, and load from settlements. The lake biogeochemical model simulates total and bioavailable nutrient species and carbon. The processes affecting carbon cycling are mineralisation, photosynthesis, respiration, sedimentation and exchange of CO₂ through the water-air interface. It predicts the co-impact of dissolved inorganic nitrogen and phosphate on phytoplankton growth and, therefore, on eutrophication, carbon sequestration in sediments and CO­₂ concentrations and emissions from lakes. Vemala v3 has been tested in the Tuusulanjärvi lake, a eutrophic lake in Southern Finland, to better understand the role of aquatic environments in carbon cycling.

Presentation Preference: Poster

Primary Presenter: Marie Korppoo, Finnish Environment Institute (marie.korppoo@syke.fi)

Authors:

Marie Korppoo, Finnish Environment Institute  (marie.korppoo@syke.fi)

Inese Huttunen, Finnish Environment Institute  (inese.huttunen@syke.fi)

Markus Huttunen, Finnish Environment Institute  (markus.huttunen@syke.fi)