Jörundur Svavarsson

Biochemical indicators of pollution exposure in shorthorn sculpin (Myoxocephalus scorpius), caught in four harbours on the southwest coast of Iceland

Shorthorn sculpins (Myoxocephalus scorpius) were caught in four Icelandic harbours, differing in size, use and traffic. Biochemical responses in liver were measured and chemicals analysed in bile. Eyrarbakki harbour, which has not been in use for many years was chosen as a control site. Njar partial differentialvík harbour is a small fishing harbour and a marina, Sandger partial differentiali harbour is a large fishing harbour, and Reykjavík harbour is a large fishing harbour and an international transport harbour. Higher levels of DNA-adducts and cytochrome P4501A (CYP1A) in the fish from the harbours in Sandger partial differentiali, Njar partial differentialvík and Reykjavík, compared to Eyrarbakki harbour, indicate PAH exposure. This was confirmed by PAH analysis in bile. The higher activities of the antioxidant enzymes catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) in fish caught in Sandger partial differentiali, than in fish caught in the other harbours, indicate exposure of sculpin to prooxidative compounds in Sandger partial differentiali harbour. Shorthorn sculpin seems to be a convenient species for monitoring pollution in northern coastal areas.

Hydrothermal vent communities at the shallow subpolar Mid-Atlantic ridge

A new type of animal community has been found near hot vents in the subpolar Atlantic at 100 to 106 m depth off Kolbeinsey on the Jan-Mayen ridge. Incubation of high temperature fluids yielded cultures of undescribed hyperthermophilic eu- and archaebacteria, growing in a temperature range between 70° and 110°C depending on the isolates. Bacteria are closely related to species occurring within deep sea hydrothermal areas. In contrast to deep-sea vent sites of the Mid-Atlantic and other oceans, the Kolbeinsey macro- and meiofauna consists of species reported from non-vent areas in the boreal Atlantic and adjacent polar seas. The most abundant forms are a solitary hydroid polyp and two sponges. Kolbeinsey is an isolated and young area of hydrothermal activity at relatively low depth and in highly productive waters; these findings could indicate a model for an early evolutionary step towards the formation of a genuine specialized vent community.

The deep-sea asellote (Isopoda, Crustacea) fauna of the Northern Seas: species composition, distributional patterns and origin

The marine asellote (Isopoda, Crustacea) fauna of the Northern Seas, i.e. the Norwegian, Greenland, Iceland and North Polar Seas, contains 106 species. Most of them occur in shallow waters, but the number of species declines rapidly with increased depth. Half the species are endemic and those occurring also outside the Northern Seas are mainly found in the North Atlantic. The endemism of species is low ( 60%) at depths > 750 m. Only a single endemic asellote genus is recorded

Distribution and diversity patterns of asellote isopods (Crustacea) in the deep Norwegian and Greenland Seas

Abstract Distribution and diversity patterns of asellote isopods (Crustacea) of the deep Norwegian and Greenland Seas are described. The asellotes show the same pattern of rapid faunal change across the upper continental slope as commonly described elsewhere. Here the rate of species replacement is maximum at depths of 800–1000m, but decreases towards greater depths. The distribution of the asellotes shows some correlations to the distribution of sediment types. Species diversity is maximum at 800m and decreases with depth. The species diversity pattern is related here to heterogeneity of the sediments and different species immigration rates into shallow and deep Arctic waters.

Biology of the Greenland shark Somniosus microcephalus

Greenland shark Somniosus microcephalus is a potentially important yet poorly studied cold-water species inhabiting the North Atlantic and Arctic Oceans. Broad-scale changes in the Arctic ecosystem as a consequence of climate change have led to increased attention on trophic dynamics and the role of potential apex predators such as S. microcephalus in the structure of Arctic marine food webs. Although Nordic and Inuit populations have caught S. microcephalus for centuries, the species is of limited commercial interest among modern industrial fisheries. Here, the limited historical information available on S. microcephalus occurrence and ecology is reviewed and new catch, biological and life-history information from the Arctic and North Atlantic Ocean region is provided. Given the considerable by-catch rates in high North Atlantic Ocean latitudes it is suggested that S. microcephalus is an abundant predator that plays an important, yet unrecognized, role in Arctic marine ecosystems. Slow growth and large pup sizes, however, may make S. microcephalus vulnerable to increased fishing pressure in a warming Arctic environment.

Feeding by asellote isopods (Crustacea) on foraminifers (Protozoa) in the deep sea

Analysis of gut contents of two deep-sea asellote isopod species, Ilyarachna hirticeps and Eurycope inermis (Munnopsidae, Asellota, Isopoda, Crustacea), showed that they were preying on benthic foraminifers. Benthic foraminifers with hard tests were more frequent in I. hirticeps guts than in E. inermis. I. hirticeps, having robust mandibles, is capable of crushing large calcareous and agglutinating foraminifers with hard tests. The presence of foraminiferal fecal pellets (stercomata), along with fine mineral particles and globigerinacean tests in I. hirticeps guts, shows that it was preying on the large, loosely agglutinating foraminifer, Oryctoderma sp. A. E. inermis swallowed whole, medium sized, calcareous foraminifers, which it apparently was unable to crush with its slender mandibles. The guts of E. inermis contained an abundance of mineral particles and globigerinacean tests. These are conjectured to be mashed remains of certain agglutinating foraminifers with soft tests, rather than being evidence of detritivory. It is suggested that feeding on foraminifers by asellotes may be common and may significantly affect the foraminiferal community.

Distribution and diversity of desmosomatid and nannoniscid isopods (Crustacea) on the Greenland-Iceland-Faeroe Ridge

The distribution and diversity of isopods (Crustacea, Isopoda; families Desmosomatidae Sars, 1897 and Nannoniscidae Hansen, 1916) was examined in Icelandic waters where a diversity of water masses (temperature range −0.9 to 12°C) occurs and the topography is characterized by the large and shallow Greenland–Iceland–Faeroe (GIF) Ridge extending across the North Atlantic in an east-west direction. Both families were species rich in the area, in total occurring with 34 species in 20 genera. Most of the species were restricted either to the north (10) or to the south (14) of the GIF Ridge, occurring either in cold (−0.8 to 2.8°C) or warm (>2°C) water masses. Five species were found on both sides of the Ridge, occurring at a wide range of temperatures (−0.9 to >4°C), while another five species extend across the GIF Ridge. Most species occurred in two and more water masses and the species north of the Ridge occurred usually within narrower temperature range than the species living south of the Ridge. The water masses in association with the Ridge seem to limit distribution of most species. Despite similar number of species occurring in the areas north and south of the Ridge, the areas differ considerably in diversity pattern with depth.

Long-term temporal trends (1992–2008) of imposex status associated with organotin contamination in the dogwhelk Nucella lapillus along the Icelandic coast

Using the dogwhelk Nucella lapillus as a biomonitor, we evaluated the organotin contamination along the Icelandic coast over nearly two decades. In 2008, adult dogwhelks collected from 30 locations were examined for imposex status. In 2009, tissue concentrations of six organotin species in dogwhelks from 16 of the 30 locations were analysed using gas chromatography-mass spectrometry. Tributyltin was the most predominant residue ranging from 2.07 to 70.38 μg kg(-1) dw, while triphenyltin was also detected at concentrations up to 22.79 μg kg(-1) dw. Higher total organotin concentrations and imposex indices were observed at locations near large harbours (Reykjavík and Hafnarfjörður). By comparing the current imposex results with those of previous surveys (1992-2003), we found that recovery was slow near the large harbours, but more apparent near the smaller harbours. We also observed a notable increase in imposex at several northwest sites implying incessant input of organotins.

Diet and resource use among Greenland sharks (Somniosus microcephalus) and teleosts sampled in Icelandic waters, using δ13C, δ15N, and mercury.

Stable carbon (δ13C) and nitrogen (δ15N) isotopes and total mercury (Hg) were used to investigate diet and resource use among Greenland sharks (Somniosus microcephalus) and 14 teleosts inhabiting Icelandic waters. Greenland shark stomachs contained 11 of the teleosts sampled, along with other fishes and marine mammal tissues. Teleost resource use ranged from pelagic (e.g., Argentina silus) to benthic (e.g., Anarhichas lupus) based on δ13C, and relative trophic positions (TP, based on δ15N) ranged from 3.0 (Mallotus villosus) to 3.8 (e.g., Brosme brosme). Greenland shark δ13C indicated feeding on benthic and pelagic resources, with a high input of pelagic carbon, and δ15N indicated a relative TP of 4.3. Log[Hg] increased with δ15N (i.e., TP) from teleosts to Greenland sharks and was higher in offshore vs. inshore teleosts. Linear regressions revealed that log[Hg] was better described by both δ15N and δ13C-assigned resource use than by δ15N alone. Hg was useful for supporting the TPs suggested by δ15N, and ...

Imposex in the Dogwhelk (Nucella lapillus) due to TBT Contamination: Improvement at High Latitudes

Abstract Studies on imposex in the dogwhelks (Nucella lapillus) in Icelandic waters in 1998 show that the level of imposex has decreased considerably since 1992–1993, two years after implementation of restrictions on the use of tributyltin (TBT)-based anti-fouling paint. Vas Deferens Sequence Index (VDSI) and Relative Penis Size Index (RPSI) levels have declined considerably, both near large and small harbours. The impact area of a large harbour complex has decreased considerably, while lesser changes were seen in the impact areas near smaller harbours.