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- Holmqvist, Niklas, et al.
(författare)
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Persistent organic pollutants (POP) in a benthic omnivore - A comparison between lake and stream crayfish populations
- 2007
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Ingår i: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 66:6, s. 1070-1078
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the accumulation of PCB and DDT in crayfish populations in 10 streams in southern Sweden. The results were compared with an earlier study on crayfish in lakes from the same area. We found that the concentration of pollutants in crayfish did not differ between the two types of systems. Variation in body burden was higher in stream living crayfish probably because of the higher influence from pollutants deposited in the catchment area and the more dynamic transport in streams. In streams, pp'-DDE concentrations were positively correlated to trophic status (total phosphorous) while PCB did not show any correlation with the nutrient regime. Further, mean Sigma PCB and p,p'-DDE concentrations in crayfish did not correlate in streams. We suggest that the sources of the two pollutants differ for stream living crayfish. The results indicate that crayfish in streams are affected to a higher degree to pollutants in the catchment area and the precipitation regime. In lakes, internal processes govern uptake of pollutants in crayfish.
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| 2. |
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| 3. |
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| 4. |
- Larsson, Per, et al.
(författare)
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Heavy metals and stable isotopes in a benthic omnivore in a trophic gradient of lakes
- 2007
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 41:17, s. 5973-5979
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Tidskriftsartikel (refereegranskat)abstract
- Heavy metals (Cd, Hg, and Pb) and stable isotopes (N-15, C-13) in crayfish (Pacifastacus leniusculus) were studied in a trophic gradient of lakes (N = 19) in southern Sweden. Trophic indicators of the lakes as total phosphorus (tot-P) varied from 5 to 93 mu g/L. The examined lakes had no known point sources of heavy metals, but the catchment areas varied from mainly forested to agricultural land. Cd and Hg in crayfish were affected by the trophic status of the lakes, showing significant negative relationship with tot-P, total nitrogen, and chlorophyll A content and a positive relationship with lake transparency (Secchi depth). The concentration of these two heavy metals was thus higher in crayfish in the oligotrophic lakes and decreased linearly to the eutrophic ones. Pb was not related to any lake variable. Stable isotopes of carbon (delta C-13) and nitrogen (615N) in crayfish were a reflection of that found in the sediment as shown by positive linear relationships for the lakes. In the sediment of the lakes, delta C-13 signature showed significant negative relationships with the trophic indicators but positive results were shown for lake transparency. The trophic gradient of the lakes was reflected by delta C-13 in the sediment and in the crayfish. 615N in crayfish was a reflection of 615N in the sediment but the relationship was not coupled to the trophic statue of the lakes. The results from the study show that Cd and Hg in benthic omnivores as crayfish are affected by ecological processes in lakes, such as eutrophication. Stable isotopes, such as 13C and 15 N, can be used to study these ecological processes.
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| 6. |
- Persson, M E, et al.
(författare)
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Biomagnification and polychlorinated biphenyl congener distribution in an aquatic predator-prey, host-parasite system
- 2007
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268. ; 26:5, s. 837-843
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Tidskriftsartikel (refereegranskat)abstract
- Biomagnification and polychlorinated biphenyl (PCB) congener distribution was examined in a predator-prey, host-parasite system, in which Atlantic salmon (Salmo salar) preyed upon sprat (Sprattus sprattus). Eubothrium crassum was an intestinal parasite in salmon that also "preyed upon" sprat, because the parasites gained access to foodstuffs via the host (salmon) gut. Salmon contained significantly higher concentrations of total PCBs compared to both parasites and prey (sprat), but no difference in PCB concentration was found between sprat and E. crassum. Salmon biomagnified several PCB congeners from their diet (sprat), whereas parasites did not, despite the fact that both salmon and their parasites ingested the same prey. Differences in nutrient uptake mechanisms between the host and their parasites, in addition to the lack of a gastrointestinal tract in the cestode, may explain the lack of biomagnification in E. crassum. No difference was found in PCB congener distribution between parasites, salmon, and sprat. and none of the animal types showed a preference for accumulating more or less lipophilic congeners (congeners with a high or low octanol/water partition coefficient [K-ow]). Biomagnification factors for individual congeners in salmon did not increase with K-ow-rather, they were constant, as shown by a linear relationship for congener concentration in prey and predator.
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| 7. |
- Persson, M. E., et al.
(författare)
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Fractionation of delta N-15 and delta C-13 for Atlantic salmon and its intestinal cestode Eubothtium crassum
- 2007
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 71:2, s. 441-452
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Tidskriftsartikel (refereegranskat)abstract
- Stable isotopes of nitrogen (delta(15) N) and carbon (delta C-13) were measured for Atlantic salmon Salmo salar and their intestinal cestode, Eubothrium crassum, sharing the same diet. Atlantic salmon muscle tissues were enriched in N-15 and depleted in C-13 compared to their prey (sprat Sprattles sprattus sprattus) and their intestinal cestode. There was no significant difference in delta N-15 or delta C-13 between E. crassum and the sprat. Differences in nutrient uptake and intestine physiology between Atlantic salmon and E. crassum are discussed, as well as how these may give rise to different fractionations of stable isotopes between a host and its parasites. Furthermore, Atlantic salmon contained a significantly higher lipid content than their prey, which may partly explain differences in delta C-13 values between the host and its cestode. In addition, cestodes inhabiting lipid-rich hosts were also lipid rich. Larger Atlantic salmon were enriched in N-15 compared to smaller fish. Cestodes inhabiting large hosts were also enriched in N-15 compared to parasites living in smaller hosts. The last two results were explained by larger fish possibly feeding from a higher trophic level, or from larger and older prey, that resulted in both a higher lipid content and an enrichment in N-15. (c) 2007 The Authors Journal compilation (c) 2007 The Fisheries Society of the British Isles.
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| 8. |
- Persson, M E, et al.
(författare)
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Large variation in lipid content, ΣPCB and δ13C within individual Atlantic salmon (Salmo salar)
- 2007
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491. ; 145:1, s. 131-137
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Many studies that investigate pollutant levels, or use stable isotope ratios to define trophic level or animal origin, use different standard ways of sampling (dorsal, whole filet or whole body samples). This study shows that lipid content, ΣPCB and δ13C display large differences within muscle samples taken from a single Atlantic salmon. Lipid- and PCB-content was lowest in tail muscles, intermediate in anterior-dorsal muscles and highest in the stomach (abdominal) muscle area. Stable isotopes of carbon (δ13C) showed a lipid accumulation in the stomach muscle area and a depletion in tail muscles. We conclude that it is important to choose an appropriate sample location within an animal based on what processes are to be studied. Care should be taken when attributing persistent pollutant levels or stable isotope data to specific environmental processes before controlling for within-animal variation in these variables. Lipid content, ΣPCB and δ13C vary to a large extent within Atlantic salmon, therefore, the sample technique for individual fish is of outmost importance for proper interpretation of data.
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