| 1. |
- Humborg, Cristoph, et al.
(författare)
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CO2 supersaturation along the aquatic conduit in Swedish watersheds as constrained by terrestrial respiration, aquatic respiration and weathering
- 2010
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 6:7, s. 1966-1978
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Tidskriftsartikel (refereegranskat)abstract
- We tested the hypothesis that CO2 supersaturation along the aquatic conduit over Sweden can be explained by processes other than aquatic respiration. A first generalized-additive model (GAM) analysis evaluating the relationships between single water chemistry variables and pCO(2) in lakes and streams revealed that water chemistry variables typical for groundwater input, e.g., dissolved silicate (DSi) and Mg2+ had explanatory power similar to total organic carbon (TOC). Further GAM analyses on various lake size classes and stream orders corroborated the slightly higher explanatory power for DSi in lakes and Mg2+ for streams compared with TOC. Both DSi and TOC explained 22-46% of the pCO(2) variability in various lake classes (0.01-> 100 km2) and Mg2+ and TOC explained 11-41% of the pCO(2) variability in the various stream orders. This suggests that aquatic pCO(2) has a strong groundwater signature. Terrestrial respiration is a significant source of the observed supersaturation and we may assume that both terrestrial respiration and aquatic respiration contributed equally to pCO(2) efflux. pCO(2) and TOC concentrations decreased with lake size suggesting that the longer water residence time allow greater equilibration of CO2 with the atmosphere and in-lake mineralization of TOC. For streams, we observed a decreasing trend in pCO(2) with stream orders between 3 and 6. We calculated the total CO2 efflux from all Swedish lakes and streams to be 2.58 Tg C yr-1. Our analyses also demonstrated that 0.70 Tg C yr-1 are exported to the ocean by Swedish watersheds as HCO3- and CO(3)2- of which about 0.56 Tg C yr-1 is also a residual from terrestrial respiration and constitute a long-term sink for atmospheric CO2. Taking all dissolved inorganic carbon (DIC) fluxes along the aquatic conduit into account will lower the estimated net ecosystem C exchange (NEE) by 2.02 Tg C yr-1, which corresponds to 10% of the NEE in Sweden.
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| 2. |
- Österblom, Henrik, et al.
(författare)
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Making the ecosystem approach operational-Can regime shifts in ecological- and governance systems facilitate the transition?
- 2010
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Ingår i: Marine Policy. - : Elsevier BV. - 0308-597X .- 1872-9460. ; 34:6, s. 1290-1299
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Tidskriftsartikel (refereegranskat)abstract
- Effectively reducing cumulative impacts on marine ecosystems requires co-evolution between science, policy and practice. Here, long-term social-ecological changes in the Baltic Sea are described, illustrating how the process of making the ecosystem approach operational in a large marine ecosystem can be stimulated. The existing multi-level governance institutions are specifically set up for dealing with individual sectors, but do not adequately support an operational application of the ecosystem approach. The review of ecosystem services in relation to regime shifts and resilience of the Baltic Sea sub-basins, and their driving forces, points to a number of challenges. There is however a movement towards a new governance regime. Bottom-up pilot initiatives can lead to a diffusion of innovation within the existing governance framework. Top-down, enabling EU legislation, can help stimulating innovations and re-organizing governance structures at drainage basin level to the Baltic Sea catchment as a whole. Experimentation and innovation at local to the regional levels is critical for a transition to ecosystem-based management. Establishing science-based learning platforms at sub-basin scales could facilitate this process.
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