| 1. |
- Angerbjörn, Anders, et al.
(författare)
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Stable isotope analysis of harbour porpoises and their prey from the Baltic and Kattegat/Skagerrak Seas
- 2006
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 2:6, s. 411-419
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Tidskriftsartikel (refereegranskat)abstract
- The by-caught harbour porpoises in commercial fisheries have raised concerns over their conservation status in the Baltic region. One important aspect for management purposes is porpoise movements within the region. We measured stable isotopes in cod, herring and hagfish, species that are important prey for harbour porpoises in the Baltic region. Bone collagen in fish from the marine Kattegat/Skagerrak was significantly enriched in C-13 compared with collagen in fish from the brackish Baltic Sea. However, despite the isotopic variation seen in their prey, we found no difference in C-13 in harbour porpoise collagen from the two areas. In fact, only eight of 24 porpoises had isotope signatures corresponding to those estimated for the diet in the area where they were caught. Our general conclusion is that porpoises move between the Baltic and Kattegat/Skagerrak Seas. Future studies are needed to evaluate the magnitude of these movements.
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| 2. |
- Eriksson, Susanne P., 1964
(författare)
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Differences in the condition of Norway lobsters (Nephrops norvegicus (L.)) from trawled and creeled fishing areas
- 2006
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 2:1, s. 52-58
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Tidskriftsartikel (refereegranskat)abstract
- The condition of trawled and creeled Norway lobsters, Nephrops norvegicus, was compared in individuals caught along the Swedish west coast. Female and male N. norvegicus were collected from trawled and creeled areas in the spring and autumn. Their nutritional state was determined by analysing individuals for haemocyanin concentration, the dry weight/wet weight relationship in muscle and hepatopancreas and the percentage dry weight of muscle and hepatopancreas of total animal dry weight. All parameters were measured on an individual basis and checked for size dependence. Creeled individuals were generally found to be in better condition than individuals from trawled areas, and animal condition increased from spring to autumn. Autumn males from creeled sites were overall in the best condition, having the highest mean haemocyanin concentration, muscle and hepatopancreas dry weight/wet weight relationship and percentage dry weight of muscle tissue. Claw symmetry ( paired cutters) was suggested as an indicator of limb loss, with the highest occurrence found in females from trawled sites. Crusher absence had no effect on the animal's individual percentage dry weight of muscle, although the mean was lower in trawled females than in other groups. Resource limitation and physical stress are discussed as possible underlying factors affecting the observed differences.
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| 3. |
- Israelsson, Olle
(författare)
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Xenoturbella (Deuterostomia) probably feeds on dissolved organic matter
- 2008
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 4:5, s. 384-391
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Tidskriftsartikel (refereegranskat)abstract
- The enigmatic deuterostome Xenoturbella does ubiquitously contain exogenous nucleic acids. This has been used in several papers as proof of selective feeding by Xenoturbella on nuculid bivalves. However, their feeding biology is unknown and exogenous nucleic acids might not originate from their main nutrient source. I have examined the possible pathways of nutrient uptake. The animals neither took up cells nor dissolved dyes through the 'mouth'. Instead, they possessed extensive pinocytosis through the epidermis. Therefore, it is probable that the main source of nutrients is dissolved organic matter uptaken through the epidermis. This does not exclude that phagocytosis in the gastrodermis does occur, e.g. due to direct expose of the gastrodermis during asexual reproduction. The ubiquitously present exogenous nucleic acids in Xenoturbella probably do originate from such events and not from their main food source.
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| 4. |
- Kvalø Heggøy, K, et al.
(författare)
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The phylogeny of the annelid genus Ophryotrocha (Dorvilleidae)
- 2007
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 3:6, s. 412-420
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Tidskriftsartikel (refereegranskat)abstract
- Ophyotrocha is easy to keep in the laboratory and has therefore been used in several studies of evolution and speciation. The phylogenetic relationships within the group are, however, still not clear and morphological and molecular data are contradictory. Here we attempt to shed light on the phylogeny by adding an additional gene (cytochrome c oxidase subunit I) to the previous analyses of the group. However, the results are still incongruent with the results from the morphological data. We also include a species of the genus Iphitime, and conclude that this species falls within the Ophryotrocha clade. The implications are discussed.
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| 5. |
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| 6. |
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| 7. |
- Paxton, H., et al.
(författare)
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Redescription of Ophryotrocha puerilis and O. labronica (Annelida, Dorvilleidae)
- 2007
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 3:1, s. 3-19
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Tidskriftsartikel (refereegranskat)abstract
- For more than a century, it has been pointed out that most features of the original description of Ophryotrocha puerilis Claparède & Mecznikow, 1869, probably based on a mixed population of two sympatric species, agree better with the subsequently described O. labronica La Greca & Bacci, 1962. Although O. labronica was described as a protandrous hermaphrodite that could self-fertilize, the widely distributed species is mainly gonochoristic. We will designate neotypes, redescribe these two polychaetes and review their reproduction and development to remove any confusion and uncertainty surrounding the identity of these two well-known polychaetes. We will also discuss the growth and replacement of the maxillary apparatus and the morphology and distribution of the rosette glands, providing support for the molecular phylogeny of selected Ophryotrocha species.
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| 8. |
- Tönnesson, Kajsa, 1971, et al.
(författare)
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Grazing impact of Oikopleura dioica and copepods on an autumn plankton community
- 2005
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 1:5, s. 365-373
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Tidskriftsartikel (refereegranskat)abstract
- Copepods and appendicularians are major grazers in the pelagic environment. They have different retention efficiencies for prey and may therefore exert a variable grazing pressure on the spectrum of pico- to micro-plankton. We determined clearance rates of both groups at one station during 24 h in the Gullmar fjord, west Sweden, in autumn 1999. Total potential prey biomass ranged from 75 mu g C l(-1) at the surface to 14 mu g C l(-1) at 30 m with a dominance of larger dinoflagellates (10-25 mu m athecate species and Gymnodinium /Gyrodinium sp.) and the pennate diatom Pseudo -nitzschia sp. Grazer biomass was dominated by copepods (Acartia clausi, Paracalanus parvus) and appendicularians (Oikopleura dioica). O. dioica showed non-selective clearance rates of 0.7-1.8 ml mu g C-1 h(-1) on most diatoms, flagellates and ciliates, whereas Pseudo -nitzschia sp. and dinoflagellates and ciliates > 25 mu m were not removed by O. dioica. Appendicularian grazing impact was 0.06% d(-1) on the phytoplankton and 0.4% d(-1) on bacterial biomass. Despite a seven-fold higher biomass, the grazing impact of copepods on phytoplankton biomass was only 0.28% d(-1) indicating that O. dioica had a proportionally greater impact and, in contrast to copepods, also utilised bacteria. The low observed grazing impact was due to a low grazer biomass and a prey community largely unavailable to the investigated grazers.
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| 9. |
- Wilhelmsson, Dan, et al.
(författare)
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Effects of high-relief structures on cold-temperate fish assemblages: a field experiment
- 2006
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 2:2, s. 136-147
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Tidskriftsartikel (refereegranskat)abstract
- High-relief structures may influence the abundance and diversity of reef-associated fish. We conducted a field experiment to investigate whether the presence of vertical structures (PVC pipes) affects fish communities on artificial reefs. The effect of the height of the structures (1 and 3 m) was also tested. Furthermore, the effects on fish of placing artificial reefs on otherwise featureless bottoms were quantified. Algal and macro-invertebrate colonization of the reefs was also recorded. The experiment was carried out on the west coast of Sweden over a period of 1 year. The vertical structures had a positive effect on fish abundance but not on diversity. The height of the structures did not, however, influence the fish communities. Natural as well as urban vertical structures on the seafloor could have a positive effect on local fish abundance. The positive effects of artificial reefs on total fish abundance and diversity were immediate. Of the 10 species recorded, two, the black goby Gobius niger and the goldsinny wrasse Ctenolabrus rupestris , dominated over the whole survey period. There were significant temporal differences in fish abundance, and diversity increased with time.
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| 10. |
- Åkesson, Bertil, 1927, et al.
(författare)
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Biogeography and incipient speciation in Ophryotrocha labronica (Polychaeta, Dorvilleidae)
- 2005
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 1:2, s. 127-139
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Tidskriftsartikel (refereegranskat)abstract
- Crossing experiments were conducted between the Naples I (NI) strain of Ophryotrocha labronica labronica, three strains of O. l. pacifica from Japan (M3), Hawaii (WH) and Los Angeles (LA), two strains of O. labronica from Australia and one from an unknown origin, discovered in a Moscow aquarium, to determine the relationships between the European and Pacific subspecies, and the newly discovered strains. Previously published data combined with new results revealed several stages in the process of speciation within the sibling group. Interpopulation crosses yielded an increased sex ratio that appears to be positively related to genetic distance and to the sex ratio of the parent strains. Fecundity data demonstrated that the three northern Pacific strains are more closely related to each other than to any other strain, confirming that they are a valid subspecies, and indicate that they are the result of natural distribution. The strain of unknown origin as well as the Australian strains clearly belong to O. l. labronica. Its isolated presence in the South Pacific may be a remnant of an earlier wider distribution or an introduction of the Mediterranean population, as the life histories of Ophryotrocha species have made them prime candidates for anthropogenic dispersals.
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| 11. |
- Öberg, Jörgen, 1958
(författare)
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Model simulations of conditions suitable for the establishment of Enteromorpha sp (Chlorophyta) macroalgal mats
- 2005
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Ingår i: Marine Biology Research. - : Informa UK Limited. - 1745-1000 .- 1745-1019. ; 1:2, s. 97-106
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Tidskriftsartikel (refereegranskat)abstract
- Floating mats of algae regularly appear in shallow bays in many coastal areas around the world. This paper presents a model that simulates the growth of ephemeral macroalgae in shallow bays, and interprets the growth according to physical and biological prerequisites. Model runs emphasized the role of internal nutrient cycling to provide the enhanced nutrient availability needed to ensure abundant growth of macroalgae. Thus, the presence of macroalgae, as well as long water residence times, influenced the nutrient cycling in the bay to support further growth of macroalgal mats.
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| 12. |
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| 13. |
- Löwenborg, Daniel, 1975-
(författare)
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Landscapes of death : GIS modelling of a dated sequence of prehistoric cemeteries in Västmanland, Sweden
- 2009
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Ingår i: Antiquity. - York : Antiquity Publications. - 0003-598X .- 1745-1744. ; 83:322, s. 1134-1143
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Tidskriftsartikel (refereegranskat)abstract
- We will never be able to excavate everything – nor should we – but it would be good to know howto make the best use of what is visible in the landscape to write social prehistories. In this projectthe author creates a set of parameters for the 1000 mound-cemeteries seen north of Lake M¨alarenand clusters them by period, using 51 examples that have been excavated and dated. The resultis that 1000 cemeteries can now be allocated to period, with that special kind of confidence inwhich statisticians rejoice.
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| 14. |
- Hagberg, Mats, 1951, et al.
(författare)
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Incidence of Raynaud's phenomenon in relation to hand-arm vibration exposure among male workers at an engineering plant a cohort study.
- 2008
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Ingår i: Journal of occupational medicine and toxicology (London, England). - : Springer Science and Business Media LLC. - 1745-6673. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: The objective of this study was to assess the incidence of Raynaud's phenomenon in relation to hand-arm vibration exposure in a cohort consisting of male office and manual workers. METHODS: The baseline population consisted of 94 office and 147 manual workers at an engineering plant. Raynaud's phenomenon (RP) was assessed at baseline and at follow up (at 5, 10 and 15 years). A retrospective and a prospective cohort analysis of data were done. Hand-arm vibration exposure dose was defined as the product of exposure duration and the weighted hand-arm vibration exposure value according to ISO 5349-1. RESULTS: The retrospective/prospective incidence of Raynaud's phenomenon was 16/14 per 1000 exposure years among exposed and 2.4/5.0 per 1000 years among the not exposed. The retrospective dose response curve based on 4 dose classes showed that class 2, 3 and 4 had similar response and showed higher incidence than the not-exposed. The dose with RP response to hand-arm vibration corresponded to a 10 year A(8) value between 0.4-1.0 m/s2. CONCLUSION: The results indicate that the EU directive on an action value for hand-arm vibration of 2.5 m/s2 is not too low. Rather, it suggests that employers should take on actions even at exposure values of 1 m/s2A(8).
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| 15. |
- Routh, Joyanto, 1968-, et al.
(författare)
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Characterization and Origin of Dissolved Organic Carbon in Yegua Ground Water in Brazos County, Texas
- 2005
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Ingår i: Groundwater. - : John Wiley & Sons. - 1745-6584. ; 39:5, s. 760-767
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Dissolved organic carbon (DOC) concentrations in five shallow (< 20 m) and three deeper wells (27 to 30 m) in the Eocene Yegua Formation (Brazos County in east-central Texas) ranged from 92 to 500 ￜm. Characterization of high, intermediate, and low molecular weight DOC fractions (HMW > 3000 amu, IMW 1000 to 3000 amu, and LMW 500 to 1000 amu) and combined neutral sugar analyses provide information on organic matter sources in the Yegua aquifers. Combined neutral sugars ranged in concentration from 0.6 to 2.7 ￜmol/L and comprised 0.8% to 6.7% of DOC in ground water. Glucose was the most abundant neutral sugar, followed by xylose and galactose, arabinose, mannose, rhamnose, and fucose. These combined neutral sugars were more diagenetically altered in shallow, oxic ground water as indicated by high mole % fucose + rhamnose and low neutral sugar yield. The precursors for neutral sugars are most probably angiosperm leaves, which show a similar distribution pattern of neutral sugars. Ground water DOC was depleted in 13C relative to soil-zone organic matter (OM) (-16ￜ to -19ￜ). The d13C values of bulk DOC and HMW DOC ranged from -24ￜ to ￜ32ￜ, whereas LMW and IMW DOC ranged from -32ￜ to -34ￜ and ￜ16ￜ to ￜ28ￜ, respectively. This variability in d13C values is probably related to microbial processes and selective preservation of OM. Carbon isotope analyses in bulk and different molecular weight DOC fractions imply a predominantly C3 OM source and a low contribution of soil-zone OM to DOC.
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