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| 2. |
- Andrén, Thomas, 1954-, et al.
(author)
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Östersjön förändras ständigt
- 2005
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In: Upsala nya tidning. - 1104-0173. ; :8/6:8 juni
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Journal article (pop. science, debate, etc.)
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| 3. |
- Conley, Daniel, et al.
(author)
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Hypoxia-Related Processes in the Baltic Sea
- 2009
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:10, s. 3412-3420
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Journal article (peer-reviewed)abstract
- Hypoxia, a growing worldwide problem, has been intermittently present in the modern Baltic Sea since its formation ca. 8000 cal. yr BP. However, both the spatial extent and intensity of hypoxia have increased with anthropogenic eutrophication due to nutrient inputs. Physical processes, which control stratification and the renewal of oxygen in bottom waters, are important constraints on the formation and maintenance of hypoxia. Climate controlled inflows of saline water from the North Sea through the Danish Straits is a critical controlling factor governing the spatial extent and duration of hypoxia. Hypoxia regulates the biogeochemical cycles of both phosphorus (P) and nitrogen (N) in the water column and sediments. Significant amounts of P are currently released from sediments, an order of magnitude larger than anthropogenic inputs. The Baltic Sea is unique for coastal marine ecosystems experiencing N losses in hypoxic waters below the halocline. Although benthic communities in the Baltic Sea are naturally constrained by salinity gradients, hypoxia has resulted in habitat loss over vast areas and the elimination of benthic fauna, and has severely disrupted benthic food webs. Nutrient load reductions are needed to reduce the extent, severity, and effects of hypoxia.
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| 5. |
- Filipsson, Helena L., 1973, et al.
(author)
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A major change in the phytoplankton of a Swedish sill fjord - A consequence of engineering work?
- 2005
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In: Estuarine Coastal and Shelf Science. - : Elsevier BV. - 0272-7714. ; 63:4, s. 551-560
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Journal article (peer-reviewed)abstract
- A major phytoplankton change occurred during the late 1930s and early 1940s in Koljo Fjord, a sill fjord on the Swedish west coast. Dinoflagellate cyst concentrations increased tenfold over a short period of time, front hundreds of cysts per gram sediment to thousands; and the species composition of both dinoflagellate cysts and diatoms changed markedly. These changes took place during a period of extensive engineering work at the entrance to the fjord from the Skagerrak. At this time, the entire passage was straightened, a new channel was built in a previously shallow area, and the old connection was closed. This study investigates whether this engineering work could have sufficiently altered the surface-water circulation to bring about the change in the phytoplankton composition. Several mechanisms are explored by which the construction could have influenced the phytoplankton in the fjord. The primary mechanism is probably increased efficiency of tidal-generated surface-water exchange in the fjord, resulting in a larger transport of surface water from the Skagerrak and consequently a changed surface-water environment. This Study highlights how engineering work can have a Substantial impact on the local and regional marine environment, a factor that must not be overlooked in environmental planning. (c) 2005 Elsevier Ltd. All rights reserved.
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| 7. |
- Harland, Rex, et al.
(author)
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Dinoflagellate cysts and hydrographical change in Gullmar Fjord, west coast of Sweden.
- 2006
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In: The Science of the total environment. - : Elsevier BV. - 0048-9697. ; 355:1-3, s. 204-31
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Journal article (peer-reviewed)abstract
- This high-resolution study of the latest Holocene dinoflagellate cyst record from Gullmar Fjord, on the west coast of Sweden, provides evidence for the recognition of two major dinoflagellate communities within the fjord over the last 85 years. These communities may have their origins with the history of cultural eutrophication within the region, but are more likely to be associated with the wider phenomenon of the North Atlantic Oscillation and/or the complex hydrographical response of the fjord to various changing climatic environments between 1915 and 1999. The changing dinoflagellate cyst populations are compared in detail with the many hydrographical parameters available from this well studied fjord with its long instrumental records. Indeed the dinoflagellate cysts fail to demonstrate a convincing ongoing eutrophication record for the fjord but do show a major change in the cyst assemblages at about 1969/1970 at a time when the NAO was changing from a negative phase to the present-day positive phase. Gullmar Fjord is important in the history of dinoflagellate cyst studies, being the site of the 1954 study by Erdtman in which viable cysts, produced within the phytoplankton, were first documented within the water column.
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| 9. |
- Nordberg, Kjell, et al.
(author)
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Stable carbon isotope evidence of the establishment of a new, opportunistic foraminiferal fauna in a Swedish Skagerrak fjord basin, in 1979/1980
- 2009
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In: Marine Micropaleontology. - : Elsevier BV. - 1872-6186 .- 0377-8398. ; 73:1-2, s. 117-128
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Journal article (peer-reviewed)abstract
- Significant faunal changes reported fromrecent, coastal environments,which are not directly influenced by urban and industrial impact, are rarely seen. In Gullmar Fjord on the Swedish west coast, a significant foraminiferal fauna change occurred in connectionwith severe low-oxygen conditions that evolved in thewinter of 1979/1980. A foraminiferal fauna marked by common Skagerrak–Kattegat species, which had previously characterised the deep fjord basin, was replaced by the opportunistic, low-oxygen tolerant species Stainforthia fusiformis (Williamsson). To study this phenomenon further we performed stable oxygen and carbon isotope analyses on the indicator species itself, S. fusiformis, both on specimens from sediment cores representing approximately the last 85 years and on living (stained) individuals taken from a transect across the deep fjord basin. Our purpose was to detail how and why S. fusiformis, came to dominate the fauna. The oxygen isotope results suggest that salinities and temperatures in the deep basin have been relatively constant over the last c. 85 years, while the carbon isotopes show a significant change towards more negative values in association with the faunal shift of 1979/1980. The combined results from both the cores and the surface sediments suggest that S. fusiformis did not inhabit the deep basin until 1980. Before then, almost all specimens of S. fusiformis were small sized and their carbon isotope values suggest they were re-deposited shallow-water specimens that had been transported down to the central, deep basin as part of a suspension load. After a major faunal extinction in 1979–1980, S.fusiformis of all sizes suddenly appeared in large numbers and their carbon isotopic values were similar to the signal from registered in the recent, living fauna within the deep basin. This suggests that the opportunistic S. fusiformis established itself in the deep basin as a consequence of the severe low-oxygen event and the faunal crash of the previously dominating Skagerrak–Kattegat fauna.
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