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| 2. |
- Conley, D.J., et al.
(författare)
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Hypoxia in the baltic sea and basin-scale changes in phosphorus biogeochemistry
- 2002
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 36:24, s. 5315-5320
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Tidskriftsartikel (refereegranskat)abstract
- Deep-water oxygen concentrations in the Baltic Sea are influenced by eutrophication, but also by saltwater inflows from the North Sea. In the last two decades, only two major inflows have been recorded and the lack of major inflows is believed to have resulted in a long-term stagnation of the deepest bottom water. Analyzing data from 1970 to 2000 at the basin scale, we show that the estimated volume of water with oxygen, <2 mL L-1, was actually at a minimum at the end of the longest so-called stagnation period on record. We also show that annual changes in dissolved inorganic phosphate water pools were positively correlated to the area of bottom covered by hypoxic water, but not to changes in total phosphorus load, thus addressing the legacy of eutrophication on a basinwide scale. The variations in phosphorus pools that have occurred during the past decades do not reflect any human action to reduce inputs. The long residence time and internally controlled variation of the large P pool in the Baltic Sea has important implications for management of both N and P inputs into this eutrophicated enclosed basin.
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| 3. |
- Conley, D., et al.
(författare)
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The myth of the Baltic stagnation period.
- 2003
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Ingår i: Environmental Science and Technology. - 1086-931X .- 1520-6912. ; 36, s. 5315-5320
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Humborg, C., et al.
(författare)
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Silicon retention in river basins : Far-reaching effects on biogeochemistry and aquatic food webs in coastal marine environments
- 2000
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Ingår i: Ambio. - 0044-7447 .- 1654-7209. ; 29:1, s. 45-50
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Tidskriftsartikel (refereegranskat)abstract
- Regulation of rivers by damming as well as eutrophication in river basins has substantially reduced dissolved silicon (DSi) loads to the Black Sea and the Baltic Sea. Whereas removal of N and P in lakes and reservoirs can be compensated for by anthropogenic inputs in the drainage basins, no such compensation occurs for DSi. The resulting changes in the nutrient composition (DSi:N:P ratio) of river discharges seem to be responsible for dramatic shifts in phytoplankton species composition in the Black Sea. In the Baltic Sea, DSi concentrations and the DSi:N ratio have been decreasing since the end of the 1960s, and there are indications that the proportion of diatoms in the spring bloom has decreased while flagellates have increased. The effects on coastal biogeochemical cycles and food web structure observed in the Black Sea and the Baltic Sea may be far reaching, because it appears that the reductions in DSi delivery by rivers are probably occurring worldwide with the ever increasing construction of dams for flow regulation.
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| 5. |
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| 6. |
- Pers, C, et al.
(författare)
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Modelling dissolved organic carbon turnover in humic Lake Ortrasket, Sweden
- 2001
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Ingår i: Environmental Modelling and Assessment. - 1420-2026 .- 1573-2967 .- 0167-6369 .- 1573-2959. ; 6:3, s. 159-172
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Tidskriftsartikel (refereegranskat)abstract
- The organic carbon balance of a lake with high input of allochthonous organic carbon is modelled integrating physical, chemical and biological processes. The physical model captures the behaviour of real thermal stratification in the lake for different flow situations during the period 1993-1997. The dissolved organic carbon model is based on simulated trajectories of water parcels. By tracking parcels, account is kept of environmental factors such as temperature and radiation as well as DOC quality for each parcel, The DOC concentration shows seasonal variations primarily dependent on inflow. The organic matter degradation (bacterial- and photodegradation) in the lake amounts to 1.5-2.5 mg C l(-1) yr(-1), where photooxidation is responsible for approximately 10%. The estimated DIC production in the lake is large compared to sediment mineralisation and primary production. The main conclusion is that the model with the selected parameterisations of the degradation processes reasonably well describes the DOC dynamics in a forest lake.
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| 7. |
- Ringbom, A, et al.
(författare)
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The B-10,B-11(n, p)Be-10,Be-11 reactions at E-n=96 MeV
- 2001
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Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 679:3-4, s. 231-250
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Tidskriftsartikel (refereegranskat)abstract
- Double-differential cross sections of the B-10,B-11(n,p)Be-10,Be-11 reactions have been measured at 96 MeV in the angular range 0 degrees -30 degrees for excitation energies up to 35 MeV. The spectra have been decomposed into different multipolarities usi
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