Boeckella antiqua n. sp. (Copepoda,Calanoida, Centropagidae) from Patagonia

Boeckella antiqua n. sp. from samples collected in an ephemeral pond on the Patagonian plateau is described and illustrated. Diagnostic features of B. antiqua are almost exclusively related to the male fifth pair of legs, females being almost indistinguishable from those of the closely related B. poppei. The two-segmented, spine-bearing left endopod of the male fifth leg suggests that it may be the basal species in the genus.     

Factors influencing the distribution of digenetic trematode infections in a mudsnail (Hydrobia ventrosa) population inhabiting salt marsh ponds in Iceland

This study analyzed the influence of several abiotic and biotic variables on the distribution of digenetic trematode infections in a mudsnail, Hydrobia ventrosa, population inhabiting 12 ponds on the Melabakkar salt marsh in Iceland, the northwestern limits of the geographical distribution. Nine trematode species were found to infect the snail population, which included Microphallus pirum, Microphallus breviatus, Microphallus claviformis, Maritrema subdolum (Microphallidae), Cercaria Notocotylidae sp. 11 Deblock, 1980, C. Notocotylidae sp. 12 Deblock, 1980, C. Notocotylidae sp. 13 Deblock, 1980 (Notocotylidae), Cryptocotyle concavum (Heterophyidae), and Psilostomum brevicolle (Psilostomatidae). Correlations between biotic variables (snail density in the ponds and vegetation cover), abiotic variables (distance of each pond from the sea, pond elevation above chart datum, size, average depth, salinity, and some characters of the littoral zone and sediments), and trematode infections were analyzed. These variables indirectly affected the trematode infections because some determined how attractive the ponds were for the final hosts, which were various species of marine and shore birds. We propose that their habitat use and defecating habits are the main determinants of the trematode distribution in the area.     

Subglacial refugia in Iceland enabled groundwater amphipods to survive glaciations

An endemic family of subterranean amphipods (Crustacea) has recently been discovered in Iceland, in addition to a new species of a previously known amphipod family. These findings are remarkable because Iceland was covered by glaciers from about 2.6 million BP to about 10,000 BP and is isolated on the mid-Atlantic Ridge, far from the North American and European continents. We argue that there were subglacial refugia in Iceland during the Quaternary glacial period. The presence of subterranean amphipods, belonging to an old group with its present distribution mainly in North America and the Eurasian continent, indicates past contact of subterranean fresh waters of Iceland and the North Atlantic continent. The amphipods currently found in Iceland may have been present in Greenland at 40 Ma, when the precursor of Iceland drifted together with the hot spot (Iceland plume) from Greenland.     

Hybridization of glaucous gull (Larus hyperboreus) and herring gull (Larus argentatus) in Iceland: mitochondrial and microsatellite data

Large white-headed gulls provide an interesting group of birds for studies of hybridization. The group is composed of 20 species of recent origin, often with weak reproductive barriers. Here we report the results from a study on the glaucous gull Larus hyperboreus, an Arctic species which has been breeding in Iceland for centuries, and the herring gull Larus argentatus which has a wide distribution in Europe but colonized Iceland in 1920s. Previous studies, based on morphological variation indicated hybridization between the two species in Iceland, have been questioned as it may just reflect variation within the species. Here we evaluate whether hybridization has occurred between the two species in Iceland by studying variation in microsatellites and mtDNA. The analysis is based on feathers taken from wings sampled in Iceland over a period of 40 years. The results are compared with samples obtained from East Greenland and published sequences of samples obtained throughout Europe. The genetic analysis reveals a distinctive grouping of the two species, although they present a shallow genealogy and an extensive sharing of the genetic variants between the two species. Several individuals show admixture for molecular markers, which may result from an incomplete lineage sorting although geographical patterns of both mtDNA haplotypes and microsatellites strongly indicate a recent hybridization in Iceland.     

Geographical variation of the furanocoumarin composition of the fruits of Icelandic Angelica archangelica

Angelica archangelica fruits were collected from 64 locations around Iceland and analysed for furanocoumarins by high-performance liquid chromatography. The average furanocoumarin content was found to be 22.5 mg/g, ranging from 14.0 to 31.6 mg/g. Whereas imperatorin was the main compound in all samples, the order of other compounds was highly diverse. Considerable differences were observed between individuals from the same location and between neighbouring locations. However, strong geographical impact was observed on the composition, with isoimperatorin and bergapten being more pronounced in South Iceland, and oxypeucedanin and an unidentified compound being more pronounced in North Iceland and absent in many samples from South Iceland.     

Fine-scale parallel patterns in diversity of small benthic Arctic charr (Salvelinus alpinus) in relation to the ecology of lava/groundwater habitats

It is critical to study factors that are important for origin and maintenance of biological diversity. A comparative approach involving a large number of populations is particularly useful. We use this approach to study the relationship between ecological factors and phenotypic diversity in Icelandic Arctic charr (Salvelinus alpinus). Numerous populations of small benthic charr have evolved in lava springs in Iceland. These charr appear morphologically similar, but differ in important morphological features related to feeding. We found a clear relationship between diversity in morphology, diet, and ecological factors among populations. In particular, there were clear differences in morphology and diet between fish coming from habitats where the lava spring flowed on as a stream compared to habitats where the lava spring flowed into a pond. Our study shows that ecological factors are important for the origin and maintenance of biological diversity. The relationship between phenotype and ecological factors are observed on a fine scale, when comparing numerous populations that are phenotypically similar. This strongly suggests that for understanding, managing, and conserving biological diversity important ecological variables have to be taken into the account.     

Composition of the founding population of Iceland: biological distance and morphological variation in early historic Atlantic Europe

We examined the composition of the founding population of Iceland through the study of morphological traits in skeletons from Iceland, Ireland, Norway, and Greenland. This is the first study to address this issue from the Settlement Period of Iceland and contemporary samples from Ireland. We pose the following questions: 1) Was the founding population of Iceland of mixed or homogeneous origin? 2) Is there evidence for a significant Irish cohort in the founding population, as suggested in medieval Icelandic literature? Analysis of biodistance revealed that both Settlement Age and later samples from Iceland showed a greater degree of phenetic similarity to contemporary Viking Age Norwegians than to samples obtained from early medieval Ireland. Analysis of among‐individual morphological variation showed that the Settlement Age population of Iceland did not exhibit an increase in variation in comparison to other populations in the sample, suggesting a relatively homogenous origin. However, estimation of admixture between the Irish and Norwegian populations indicated that 66% of the Icelandic settlers were of Norwegian origin. Comparison of the Icelandic samples to hybrid samples produced by resampling the Viking Age Norwegian and early medieval Irish samples revealed that the Icelandic samples are much closer to the Norwegian samples than expected, based on a 66:34 mixture of Norwegian and Irish settlers. We conclude that the Settlement Age population of Iceland was predominantly (60–90%) of Norwegian origin. Although this population was relatively homogenous, our results do not preclude significant contributions from Ireland as well as other sources not represented in our analysis. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.     

Molecular evidence of the survival of subterranean amphipods (Arthropoda) during Ice Age underneath glaciers in Iceland

Two endemic groundwater arthropod crustacean species, Crangonyx islandicus and Crymostygius thingvallensis, were recently discovered on the mid‐Atlantic volcanic island of Iceland. The extent of morphological differences from closest relatives, endemism, along with the geographic isolation of Iceland and its complete coverage by glaciers 21 000 years ago, suggests that these two species have survived glaciation periods in sub‐glacial refugia. Here we provide strong support for this hypothesis by an analysis of mitochondrial genetic variation within Crangonyx islandicus. Our results show that the species is divided into several distinct monophyletic groups that are found along the volcanic zone in Iceland, which have been separated by 0.5 to around 5 million years. The genetic divergence between groups reflects geographic distances between sampling sites, indicating that divergence occurred after the colonization of Iceland. The genetic patterns, as well as the dependency of genetic variation on distances from the tectonic plate boundary and altitude, points to recent expansion from several refugia within Iceland. This presents the first genetic evidence of multicellular organisms as complex as crustacean amphipods which have survived glaciations beneath an ice sheet. This survival may be explained by geothermal heat linked to volcanic activities, which may have maintained favourable habitats in fissures along the tectonic plate boundary in Iceland during glaciations.     

Plant survival in Iceland during periods of glaciation?

Aim The paper addresses the classical question of possible plant survival in Iceland during the last glacial period in the light of a palaeobotanical record from northern Iceland, spanning the period 11,300–9000 BP , including the Younger Dryas stadial. We review the Late Cenozoic fossil plant record, the past debate on glacial plant refugia in Iceland, and the evidence for ice-free areas during the Weichselian. Location The investigated lake sediment record comes from Lake Torfadalsvatn, which is situated in the northwestern part of the Skagi peninsula in northern Iceland. Methods The sediment chronology was constructed from the cccurrence of the Vedde Ash and the Saksunarvatn ash, two well-dated Icelandic tephras, together with the results from five AMS and conventional radiocarbon dates performed on bulk sediment samples. The vegetational reconstruction was based on detailed pollen analysis of the sediment sequence. Results The pollen analysis revealed that many of the taxa present in the area prior to the Younger Dryas stadial continued to produce pollen during that cold event. The more or less immediate reappearance of a few other pollen taxa at the Younger Dryas-Preboreal boundary suggests that these plants also survived, even if they did not produce sufficient pollen to be recorded during the Younger Dryas stadial. Main conclusions We conclude that the relatively high plant diversity found in high Arctic areas and present-day nunataks in Iceland and Greenland, together with the fact that many plant species were able to survive the Younger Dryas stadial on the Skagi peninsula, suggest that species with high tolerance for climate fluctuations also survived the whole Weichselian in Iceland. This conclusion is supported by recent palaeoclimatic data from ice-cores and deep-sea sediments, indicating that Icelandic climate during the last glacial was only occasionally slightly colder than during the Younger Dryas stadial.     

Serum levels of marine-derived n-3 fatty acids in Icelanders, Japanese, Koreans, and Americans--a descriptive epidemiologic study

In the 1990s Iceland and Japan were known as countries with high fish consumption whereas coronary heart disease (CHD) mortality in Iceland was high and that in Japan was low among developed countries. We described recent data fish consumption and CHD mortality from publicly available data. We also measured CHD risk factors and serum levels of marine-derived n-3 and other fatty acids from population-based samples of 1324 men in Iceland, Japan, South Korea, and the US. CHD mortality in men in Iceland was almost 3 times as high as that in Japan and South Korea. Generally, a profile of CHD risk factors in Icelanders compared to Japanese was more favorable. Serum marine-derived n-3 fatty acids in Iceland were significantly lower than in Japan and South Korea but significantly higher than in the US.     

Gene flow and lack of population differentiation in Atlantic cod, Gadus morhua L., from Iceland, and comparison of cod from Norway and Newfoundland

Restriction analysis of mitochondrial DNA was used to study genetic variation and geographic population structure of Atlantic cod from localities around Iceland. Gene phylogenies were constructed and geographic locations superimposed on these. The variation was not localized. Estimated gene flow was large. Thus, Atlantic cod in Iceland belong to a single genetic population. Analyses of published sequence variation of cod from Norway and Newfoundland showed that the extensive continuity of intraspecific phylogeny of cod in Iceland, which is very similar to other marine organisms with a similar life history, extends from Norway to Newfoundland and possibly to larger areas of the Atlantic.     

Floristic turnover in Iceland from 15 to 6 Ma – extracting biogeographical signals from fossil floral assemblages

Aim This study aims to document the floristic changes that occurred in Iceland between 15 and 6 Ma and to establish the dispersal mechanisms for the plant taxa encountered. Using changing patterns of dispersal, two factors controlling floristic changes are tested. Possible factors are (1) climate change, and (2) the changing biogeography of Iceland over the time interval studied; that is, the presence or absence of a Miocene North Atlantic Land Bridge. Location The North Atlantic. Methods Species lists of fossil plants from Iceland in the time period 15 to 6 Ma were compiled using published data and new data. Closest living analogues were used to establish dispersal properties for the fossil taxa. Dispersal mechanisms of fossil plants were then used to reconstruct how Iceland was colonized during various periods. Results Miocene floras of Iceland (15–6 Ma) show relatively high floristic turnover from the oldest floras towards the youngest; and few taxa from the oldest floras persist in the younger floras. The frequencies of the various dispersal mechanisms seen in the 15‐Ma floras are quite different from those recorded in the 6‐Ma floras, and there is a gradual change in the prevailing mode of dispersal from short‐distance anemochory and dyschory to long‐distance anemochory. Two mechanisms can be used to explain changing floral composition: (1) climate change, and (2) the interaction between the dispersal mechanisms of plants and the increasing isolation of proto‐Iceland during the Miocene. Main conclusions Dispersal mechanisms can be used to extract palaeogeographic signals from fossil floras. The composition of floras and dispersal mechanisms indicate that Iceland was connected both to Greenland and to Europe in the early Middle Miocene, allowing transcontinental migration. The change in prevalence of dispersal modes from 15 to 6 Ma appears to reflect the break‐up of a land bridge and the increasing isolation of Iceland after 12 Ma. Concurrent gradual cooling and isolation caused changes in species composition. Specifically, the widening of the North Atlantic Ocean prevented taxa with limited dispersal capability from colonizing Iceland, while climate cooling led to the extinction of thermophilous taxa.     

A comparison of Northeast Atlantic killer whale (Orcinus orca) stereotyped call repertoires

Killer whale call repertoires can provide information on social connections among groups and populations. Killer whales in Iceland and Norway exhibit similar ecology and behavior, are genetically related, and are presumed to have been in contact before the collapse of the Atlanto-Scandian herring stock in the 1960s. However, photo-identification suggests no recent movements between Iceland and Norway but regular movement between Iceland and Shetland. Acoustic recordings collected between 2005 and 2016 in Iceland, Norway, and Shetland were used to undertake a comprehensive comparison of call repertoires of Northeast Atlantic killer whales. Measurements of time and frequency parameters of calls from Iceland (n = 4,037) and Norway (n = 1,715) largely overlapped in distribution, and a discriminant function analysis had low correct classification rate. No call type matches were confirmed between Iceland and Norway or Shetland and Norway. Three call types matched between Iceland and Shetland. Therefore, this study suggests overall similarities in time and frequency parameters but some divergence in call type repertoires. This argues against presumed past contact between Icelandic and Norwegian killer whales and suggests that they may not have been one completely mixed population.     

The effect of the pine woolly aphid (Pineus pini) on survival,growth and natural selection in Scots pine (Pinus sylvestris) in Iceland

1. Scots pine Pinus sylvestris was originally introduced to Iceland in the beginning of the 20th Century. Extensive plantings started in the late 1940s and, in total, 2–3 million Scots pine seedlings were planted, mainly originating from two counties in northern Norway. Part of this plant material was imported as seedlings.
2. Pine woolly aphid Pineus pini was introduced to Iceland before 1940, most likely on imported seedlings in 1937.
3. High mortality of Scots pine, concurrent with high infestation of the pine woolly aphid, was observed in Iceland during the late 1950s and 1960s and planting was discontinued.
4. Provenance trials with Scots pine were established in Iceland in 2004–2006. They consisted of 15 provenances from Norway, four from Finland, four from Scotland, one from Russia, one from the Austrian Alps and three first generation Scots pine provenances from Iceland, collected from survivors of the epidemic in the 1950s and 1960s. In total, there were 28 provenances.
5. The Icelandic provenances had significantly lower P. pini infestation than all the provenances of non‐Icelandic origin, which indicates that natural selection in Scots pine in Iceland has occurred in favour of individuals less susceptible to P. pini.

     

Spatial and temporal dispersion patterns of golden perch, Macquaria ambigua, larvae in an artificial floodplain environment

Golden perch larvae were stocked into a pond and inundated floodplain system in south-eastem Australia to determine movement patterns of the larvae onto and off the floodplain area. A total of 428 larvae were caught moving from the floodplain into the pond whereas only 18 were collected moving in the reverse direction. Thirty one larvae were caught at open water sites in the pond and floodplain, but only three were collected from sites on the floodplain which provided shade, timber or water flow. Transect samples from the pond also yielded more larvae than samples from floodplain transects, indicating a distinct spatial dispersion pattern in favour of the pond.
Spatial dispersion patterns of golden perch larvae appear to correspond with gradients in water quality between the pond and floodplain habitats. Stratification occurred in the pond but did not develop on the floodplain. Water on the floodplain was cooler, harder and contained less oxygen than surface water from the pond. Die1 oscillations occurred in water temperature, pH, dissolved oxygen, carbon dioxide and acidity, but there was no significant corresponding pattern in the distribution of larvae.
Dispersion of golden perch larvae between pond and floodplain habitats is not random, and may be actively influenced by local-scale variations in water quality.     

Origin and dispersal of Potamophylax cingulatus (Trichoptera: Limnephilidae) in Iceland

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Mitochondrial cytochrome b DNA sequence variation of Atlantic cod from Iceland and Greenland

Sequence variation of a 250–bp (base pair) fragment of the mitochondrial cytochrome b gene has been studied using polymerase chain reaction and direct sequencing of 519 Atlantic cod Gadus morhua from Iceland and 78 cod from Greenland. Twenty-four variable nucleotide sites, mostly silent, define 34 haplotypes. The amount of variation is high ( ĥC =0·73, π=0·52 per 100 bp) with five haplotypes at polymorphic frequencies in Iceland and a number of widely dispersed rather rare haplotypes. A tree of genetic relationships among haplotypes has considerable homoplasy yet it is relatively shallow implying a high turnover of variants of the polymorphism. Net nucleotide genetic divergences among localities are nil. Geographic locality overall area, and inshore/offshore comparison explain none of the variation in an AMOVA, all the variation is among individuals and a null hypothesis of non-differentiation of haplotype frequencies among localities or overall areas cannot be rejected. A temporal year-class effect is found. The evolutionary difference between Greenland and Iceland cod is not significant and the percentage of variation accounted for by the Greenland/Iceland difference is half of what a temporal effect within Iceland explains. There is no evidence for considering the cod at Greenland and Iceland to consist of separate evolutionary units and the question of separate management units must address the lack of diagnostic genotypes and evidence for gene flow from clinal variation.     

Geographical variation in the breeding biology of the Purple Sandpiper Calidris maritima

Studies in Iceland (66°N) and Svalbard (78°N), combined with the results of previous work, allowed geographical comparisons of different aspects of the breeding biology of the Purple Sandpiper Calidris maritima , testing predictions that they may be related to latitude and altitude (here taken as surrogates for climatic severity). The breeding density was lowest in the polar deserts of Franz Josef Land (82°N) and highest in coastal Arctic Tern Sterna paradisaea colonies in Iceland where the terns perhaps afforded protection from predators. There was no difference in the percentages of 1-year-old (first-year) birds in the breeding populations in Svalbard and Iceland. Time of breeding was related to both latitude and altitude, being later at higher latitudes and altitudes. In Iceland, larger males and males over 1 year old nested earlier than small males and 1-year-old males, respectively. Relaying occurred in Iceland but it was not observed in Svalbard. There were no geographical differences in clutch size. Egg size was related to female size in Svalbard. There were also geographical differences in egg size associated with female size (wing length), with the largest eggs in Iceland and smallest in south Norway. Males usually attended broods and the rates at which females deserted their broods were similar in Iceland and Svalbard. Chick growth rates were similar for Iceland and Franz Josef Land. Thus, in breeding biology, Purple Sandpipers varied geographically only in breeding density, time of nesting and egg size, which was associated with female size.     

Behavior and reproduction of invertebrate animals during and after a long-term microgravity: space experiments using an Autonomous Biological System (ABS).

Aquatic invertebrate animals such as Amphipods, Gastropods (pond snails), Ostracods and Daphnia (water flea) were placed in water-filled cylindrical vessels together with water plant (hornwort). The vessels were sealed completely and illuminated with a fluorescent lamp to activate the photosynthesis of the plant for providing oxygen within the vessels. Such ecosystem vessels, specially termed as Autonomous Biological System or ABS units, were exposed to microgravity conditions, and the behavior of the animals and their reproduction capacity were studied. Three space experiments were carried out. The first experiment used a Space shuttle only and it was a 10-day flight. The other two space experiments were carried out in the Space station Mir (Shuttle/Mir mission), and the flight units had been kept in microgravity for 4 months. Daphnia produced their offspring during a 10-day Shuttle flight. In the first Mir experiment, no Daphnia were detected when recovered to the ground. However, they were alive in the second Mir experiment. Daphnia were the most fragile species among the invertebrate animals employed in the present experiments. All the animals, i.e., Amphipods, pond snails, Ostracods and Daphnia had survived for 4 months in space, i.e., they had produced their offspring or repeated their life-cycles under microgravity. For the two Mir experiments, in both the flight and ground control ecosystem units, an inverse relationship was noted between the number of Amphipods and pond snails in each unit. Amphipods at 10 hours after the recovery to the ground frequently exhibited a movement of dropping straight-downward to the bottom of the units. Several Amphipods had their legs bent abnormally, which probably resulted from some physiological alterations during their embryonic development under microgravity. From the analysis of the video tape recorded in space, for Ostracods and Daphnia, a half of their population were looping under microgravity. Such looping animals could be observed still at the end of the 4 month stay in space. No looping behavior was noted for Amphipods and pond snails.     

Distribution,abundance and biology of polar cod, <Emphasis Type="Italic">Boreogadus saida</Emphasis>, in Iceland–East Greenland waters

Recent warming has caused a northern extension in the distribution of many southern fish species in Icelandic waters. Polar cod (Boreogadus saida) around Iceland are near the southern limit of their distribution, but are poorly studied in the area. Therefore, material sampled during demersal fish surveys in March 1985–2013 and in pelagic 0-group surveys in Iceland–East Greenland waters in August–September 1974–2003 was used to investigate their distribution, abundance and biology. Demersal polar cod were most often caught on the outer shelf to the north-west and north of Iceland, but during years of widest distribution and highest abundance, they were caught farther to the east on the northern shelf. Pelagic 0-group polar cod were only caught sporadically and mainly confined to the waters off the north-west shelf of Iceland and the East Greenland shelf (southern Denmark Strait). In demersal hauls, the number of stations with polar cod decreased with increasing bottom temperature and polar cod were most widely distributed in the years 1989, 1994 and 1995. Highest numbers of demersal polar cod per haul were caught at temperatures of ?0.5 to 2.5 °C and at 200–450 m depth. The length of demersal polar cod ranged from 5 to 32 cm, while the fish caught in the pelagic trawl ranged from 2.2 to 19 cm. The polar cod in the subarctic waters north of Iceland most likely originate from the waters off East Greenland and further warming and decline in sea ice may eventually lead to the disappearance of polar cod from Icelandic waters.