| 1. |
- Bradshaw, Clare, et al.
(författare)
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Bottom trawling resuspends sediment and releases bioavailable contaminants in a polluted fjord
- 2012
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 170, s. 232-241
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Tidskriftsartikel (refereegranskat)abstract
- Sediments are sinks for contaminants in the world's oceans. At the same time, commercial bottom trawling is estimated to affect around 15 million km(2) of the world's seafloor every year. However, few studies have investigated whether this disturbance remobilises sediment-associated contaminants and, if so, whether these are bioavailable to aquatic organisms. This field study in a trawled contaminated Norwegian fjord showed that a single 1.8 km long trawl pass created a 3-5 million m(3) sediment plume containing around 9 t contaminated sediment; ie. 200 g dw m(-2) trawled, equivalent to c. 10% of the annual gross sedimentation rate. Substantial amounts of PCDD/Fs and non-ortho PCBs were released from the sediments, likely causing a semi-permanent contaminated sediment suspension in the bottom waters. PCDD/Fs from the sediments were also taken up by mussels which, during one month, accumulated them to levels above the EU maximum advised concentration for human consumption.
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| 2. |
- Green, Mattias, 1971, et al.
(författare)
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Hydrographic response of Holandsfjord to changed freshwater runoff
- 2004
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Ingår i: Journal of Geophysical Research-Oceans. - 0148-0227. ; 109:C7
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Tidskriftsartikel (refereegranskat)abstract
- The observed hydrographic conditions in the upper layers of the Norwegian Holandsfjord are analyzed as functions of the location and strength of the freshwater discharge. The data sets were sampled over 21 years and consist of mostly fortnightly observations of salinity and temperature at several stations along the fjord and daily estimates or observations of the freshwater supply. The freshwater runoff to Holandsfjord was regulated and relocated to a hydroelectric power plant at the innermost end of the fjord in 1993, and by transfer of water from neighboring watersheds the yearly average freshwater discharge increased by a factor greater than 2. Before the regulation the freshwater content in the fjord was hydraulically controlled somewhere in the outer part of the fjord, and this control remains after the regulation and has been located. When the power plant is in operation a hydraulic control appears at Enganes, the narrow contraction between the outer and inner parts of the fjord. The present investigation also shows that the surface layer responds to the regulated freshwater supply with a decreased surface layer salinity, an increased freshwater content, and an increased rate of flushing. The mean value of the wind power mixing buoyancy in the surface layer is estimated to be 6-7 mW m(-2).
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| 3. |
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