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- 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. |
- Danielsson, Åsa, 1970-, et al.
(författare)
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dentification of characteristic regions and representative stations : A study of water quality variables in the Kattegat
- 2004
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Ingår i: Environmental Monitoring & Assessment. - 0167-6369 .- 1573-2959. ; 90:1-3, s. 203-224
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Tidskriftsartikel (refereegranskat)abstract
- Gradients in nutrient distributions and the effects of eutrophication are common features in most coastal marine areas. These structures occur in aquatic systems due to spatial differences in hydrography, nutrient loading and key biogeochemical processes. Two statistical methods, cluster analysis and probability mapping, have been used in the present study to determine characteristics and patterns in water quality variables. Combined, these two methods provide a useful toot to statistically determine spatial homogeneity and representativity of areas and stations. A case study is presented here in which water quality variables (salinity, dissolved inorganic nitrogen, dissolved inorganic phosphorus and chlorophyll) in surface waters of the Kattegat are analysed for the time period 1993-1997. It was found that morphology, the proximity to sources of nutrient loading from land, nutrient uptake and the infrequent water exchange between the Baltic Sea in the south and the Skagerrak in the north all contribute to create distinct regions of water quality. Regions with concentrations significantly different from the overall mean are identified. In addition to identification of regions with similar characteristics, representative stations (as well as not representative stations) for the respective regions were made. This type of information can be used to design new or revise old monitoring programs.
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- Danielsson, Åsa, 1970-, et al.
(författare)
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Large-scale mercury variations in Lake Vänern (Sweden) 1974-1998.
- 2001
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Ingår i: Environmental Monitoring & Assessment. - 0167-6369 .- 1573-2959. ; 75, s. 223-234
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Tidskriftsartikel (refereegranskat)abstract
- Lake Vanern, the largest lake in Sweden, has been seriously contaminated with mercury during the 20th century. In the 1970's and 80's the direct load, mainly from a chlor-alkali industry in the area, of mercury was drastically reduced as a response to new legislation, from three to five tons down to between five and ten kg yr(-1). Large amounts of the disposed pollutant have accumulated in the sediments. The question posed in this work is now, is the effect of the drastic load reduction after more than two decades visible in the sediments? The question is relevant as large areas still are blacklisted for fishing, but also as a follow-up of a major remedy action. The lake also serves as a freshwater reservoir for even Sweden's second largest city. This work synthesises and compares data of mercury in the sediments from three major field programs, in 1974, 1984 and 1998. The interest is focused on both spatial heterogeneity and temporal trends. In 1974, the surface concentrations are significantly higher than in subsequent surveys. Significant differences are also found between 1984 and 1998. Significant spatial differences within the lake are found for respective year. The most contaminated area is located in the north, close to the major point source (a former chlor-alkali industry). This is also the area with the largest improvement, as a direct response to the reduction in load. Further from the outlet, the recovery is more affected by burial and transport processes out into the deeper basins.
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- 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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8. |
- Ittekot, Venu, et al.
(författare)
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Carbon Silicon Interactions.
- 2003. - 1
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Ingår i: Interactions of the Major Biogeochemical Cycles: Global Change and Human Impacts. - New York : Island Press. - 1559630655 - 9781559630658 ; , s. 311-336
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The circulation and interactions of major elements such as carbon, nitrogen, phosphorus, sulphur, oxygen, and hydrogen are critical for the maintenance of the earth's ecosystems. Human activities including agriculture, industry, and urbanization alter element interactions and contribute to major environmental problems ranging from climate change and depletion of the ozone layer to acidification of soils to the destruction of coral reefs.Interactions of the Major Biogeochemical Cyclesis a new scientific assessment of element interactions in the biosphere. It provides an up-to-date review of biogeochemistry and its effects on earth's systems, with leading experts in biogeochemical cycling in atmospheric, land, freshwater, and marine environments offering chapters that summarize and synthesize information in each discipline.The book opens with chapters on cross-cutting issues that have significance in understanding global change effects and their potential management. These chapters address:* trends in element interactions in response to global changethe effects of natural disturbancesnew approaches and methods for advancing our understanding of element interactionsthe potential for managing element interactions to address major environmental issues
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10. |
- Jönsson, Anette, et al.
(författare)
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Wave dynamics of the Baltic
- 2002
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Ingår i: Ocean Engineering. - 0029-8018 .- 1873-5258. ; 30, s. 107-126
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Tidskriftsartikel (refereegranskat)
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