Summary
Lakes are hot-spots for carbon storage and transformation, but their net contributions to the carbon cycle are complex and poorly constrained. This project is developing a suite of carbon cycling measurements that will facilitate comparative studies across gradients of trophic state, latitude, climate, and watershed characteristics. To date this project has described patterns of lake carbon cycling across broad geographic scales, and collected new data that explains regional patterns. Current work focuses on bridging-scales to understand how within-lake processes relate to continental-scale patterns.
Project Status
Ongoing
Project Description
Lakes store large amounts of carbon in their sediment, but also emit carbon dioxide to the atmosphere. These dual roles make lake contributions to the global carbon cycle complex and difficult to constrain. This project aims to develop understanding of how within-lake processes translate to continental-scale patterns of lake carbon cycling. A suite of carbon cycling measurements is being made in Swedish lakes that will facilitate comparative studies across gradients of trophic state, latitude, climate, and watershed characteristics.
Three types of studies are underway:
- Detailed measurements of specific aspects of the carbon cycle for small numbers of lakes,
- Descriptions of continental-scale patterns based on environmental monitoring data from large numbers of lakes, and
- Connections across scales from within-lake processes to continental-scale patterns.
To date, our most important observation is that non-linear relationships create thresholds that cause emergent patterns when evaluating lake carbon cycling at broad geographic scales (Seekell et al. 2018). For example, there are nonlinear relationships among light availability, nutrient concentration, and dissolved organic carbon for lakes in northern Sweden. These nonlinearities create a surprise threshold relationship where inorganic carbon fixation increases with dissolved organic carbon concentration in some regions, but decreases in others (Seekell et al. 2015). These studies are among the first to make such connections across scales, and the overall patterns and specific mechanisms described in these papers have subsequently been validated by independent studies comprising controlled experiments (Vasconcelos et al. 2018), comparative analyses (Diehl et al. 2018), paleo-limnological analyses (McGowan et al. 2018), and mathematical models (Kelly et al. 2018, Vasconcelos et al. 2018).
Long-term patterns of carbon dioxide concentration in a temperate lake. The measurements indicate that the lake is a net source of carbon dioxide to the atmosphere, but with tremendous seasonal variation.
Journal Covers
Selected Media Reports
Press Releases
- Goda fiskenyheter: Brunt vatten påverkar fisken mindre än väntat - Umeå universitet
- Good news for fishermen: “Browning” impacts fish less than expected - Umeå University
- Den globala variationen i kolets kretslopp i sjöar får sin förklaring - Umeå universitet
- Can smarter forest buffer strips along streams help to mitigate climate change? - Umeå University
- Kan skogsbrukets klimatnytta öka genom smartare bäckkantzoner? - Umeå universitet