A fine-grained sediment budget for the Sylt-Rømø tidal basin

A budget for net accumulation of fine-grained sediment (<63 μm) has been set up for the Sylt-Rømø tidal basin. Net accumulation within the basin was computed from²¹⁰Pb core dating and mapping of the intertidal and supratidal surface sediments. It was found that a yearly mean value of 58·10³ tons of sediment was deposited in the tidal basin. The largest sediment source for the net input of fine-grained sediment is the North Sea contributing about 64% to the net budget; the fluvial input and primary production contribute 14% and 15%, respectively. Local salt marsh erosion accounts for about 5% of the budget and atmospheric deposition for only 2%. The total amount of sediment deposited in the investigated area was low compared with earlier investigations in the Wadden Sea. This is explained partly by the intensive diking of the natural salt marshes fringing the area in the past, and partly by the exposed conditions of most of the intertidal flats. An index describing the trapping efficiency of the water exchanged between the North Sea and the Sylt-Rømø tidal area is defined as the ratio between yearly net sediment input from the North Sea and yearly exchanged water volume between the tidal basin and the sea. This index shows that in the Sylt-Rømø tidal basin, fine-grained suspended sediment “filters” out of the exchanged sea water at a rate that is 12 times lower than in the Gr»dyb tidal basin. It is concluded that the net deposition of fine-grained sediment in a tidal basin is mainly a function of physiographical and hydrodynamical parameters and to a lesser degree of sediment availability     

Halobacterium halobium phage øH

Phage øH, a novel virus of the archaebacterium Halobacterium halobium, resembles in size and morphology two other Halobacterium phages. One-step growth curves show a 5.5 h eclipse, a latent period of 7 h, and an apparent burst size of 170. Phage øH contains linear, double-stranded DNA which has a molecular weight of 39 x 10⁶ and a GC content of 65%. A packaging model accounting for the partial circular permutation and terminal redundancy of øH DNA is suggested. Partial homology of øH DNA with the DNA of H. halobium, predominantly with the AT-rich satellite DNA, was observed. The presence of minor restriction fragments of øH DNA which could be removed by purification of phage from single plaques suggests the existence of phage variants with rearranged DNA. A strain of H. halobium containing øH DNA was isolated which is resistant to infection by phage øH.     

Population changes of Antarctic fur seals at Nyrøysa, Bouvetøya

Antarctic fur seal Arctocephalus gazella pup production at Nyrøysa, Bouvetøya was estimated to be approximately 15,000 per annum during each of four summers from 1996 to 2002, indicating a total population of about 66,000. While the Bouvetøya population is the second largest for this species, pup production at this site still accounts for only 2.4% of the global total. This population experienced a mean annual rate of increase of 30.6% for the period 1989–1996, perhaps due, in part, to significant immigration, but has been stable since 1996. Historical accounts of significant numbers of animals being present towards the end of the period of sealing (C.1800–1930), indicate that the geographic isolation and inaccessibility of this site may have resulted in the Bouvetøya population being one of three populations that survived a series of periods of extreme exploitation of this species.     

Crustacean plankton in Høylandet

Crustacean plankton was studied in 12 lakes in theHøylandet area in 1986–87. Basic lake characteristicsare elevation 134–415 m, surface area 9–530 ha, pH 5.9–7.1,conductivity (25 °C) 12–40 µS cm^-1 andSecchi depth 4–9 m. Number ofspecies present varied between 3 and 11. Populationnumbers between 4000 and 400 000 per m² andbiomasses were within the range 30 to1800 mg m^-2 dry weight. Cladocera dominated overCopepoda in lakes with allopatric brown trout (Salmo trutta L.), on the contrary to lakes also populatedby Arctic charr (Salvelinus alpinus (L.)). Thesevariations are caused by differences in elevation,lake morphometry, water quality, fish predation andthe general distribution of the species. The largestlakes at lowest elevation were richest in species. Theacid sensitive genus Daphnia was represented by 3species. The lakes Storgrønningen (530 ha) andRøyrtjønna (27 ha) were sampled monthly in theice-free seasons of 1986–89, and Storgrønningen moreintensively from June to November in 1987 and 1988. The same6 species of Cladocera and 5 of Copepoda were presentin both lakes. Their life cycles were traditional orknown from several other Scandinavian lakes. Meanseasonal biomasses were of the range600–750 mg m^-2. At the species level, there wereconsiderable variations between years inStorgrønningen and particularly in Røyrtjønna. Noeffects of human impacts on the crustacean planktonwere found. The Høylandet lakes are representative forScandinavian oligotrophic to almost ultra-oligotrophiclakes. Storgrønningen is well qualified as a referencesystem. The between year variations in Røyrtjønna areso extreme, that any human impact could only be traced at alevel causing the extinction of species.     

Intraspecific differences in the diet of Antarctic fur seals at Nyrøysa, Bouvetøya

Intraspecific differences in the diets of many species of pinnipeds are to be expected in view of the great differences in morphology, life history and foraging behaviour between the sexes of many species. We examined the diet of the Antarctic fur seal population at Bouvetøya, Southern Ocean, to assess intersexual differences. This was made possible by the analysis of prey remains extracted from scats and regurgitations collected in areas used primarily by one or the other sex. The results indicate that both males and females feed primarily on Antarctic krill Euphausia superba with several species of fish and squid being taken, likely opportunistically given their prevalence. Significant differences were identified in the frequency of occurrence of otoliths in scats and the percentage numerical abundance of the major fish prey species in the diet. Adult males ate a smaller quantity of fish overall, but ate significantly more of the larger fish species. The greater diving capabilities of males and the fact that they are not limited in the extent of their foraging area by having to return regularly to feed dependant offspring may play a role in the differences found between the diets of males and females. Additionally, females might be more selective, favouring myctophids because they are richer in energy than krill. The absence of major differences in the diet between the sexes at this location is likely due to the high overall abundance of prey at Bouvetøya.     

Stone Age settlements at Sørøya, sub-arctic Norway: impact on the vegetation

Four pollen diagrams, which together cover the period 10400 cal bp to the present, from an area rich in Stone Age house foundations show that vegetation was increasingly influenced by man in a stepwise process. There was a modest, temporary appearance of anthropogenically-induced vegetation about 8600 cal bp. After 7100 cal bp there was a development towards semi-open birch woodland where the open patches were characterised by natural heath and meadow species and more typical apophytic taxa such as Ranunculus acris and Rumex acetosa types, grasses and juniper. The main changes towards this vegetation seem connected with the most important cultural changes, especially at about 7100 cal bp, when there was a transition to honed slate tools in the regional archaeology, at about 4000 cal bp when pottery was introduced, and at about 3000–2800 cal bp since when the use of stone artefacts gradually ceased. It is suggested that the settlements were mainly summer habitations.     

Leucistic Antarctic fur seals at Bouvetøya

One leucistic and one partially leucistic Antarctic fur seal Arctocephalus gazella were seen at Bouvetøya during the 1996/97 austral summer. Both likely came from South Georgia, where this colour morph is common. No individuals of this colour morph were sighted during three subsequent expeditions to Bouvetøya. The prevalence of this colour morph in the abundant populations of the Scotia Arc may be due to founder effect, as at least one leucistic animal was present at South Georgia when the Antarctic fur seal was close to extinction.     

Microbial community structure of sandy intertidal sediments in the North Sea, Sylt-Rømø Basin, Wadden Sea

Molecular biological methods were used to investigate the microbial diversity and community structure in intertidal sandy sediments near the island of Sylt (Wadden Sea) at a site which was characterized for transport and mineralization rates in a parallel study (D. de Beer, F. Wenzhöfer, T. Ferdelman, S.E. Boehme, M. Huettel, J.E.E. van Beusekom, M.E. Böttcher, N. Musat, N. Dubilier, Transport and mineralization rates in North Sea sandy intertidal sediments, Sylt-Romo Basin, Wadden Sea, Limnol. Oceanogr. 50 (2005) 113–127). Comparative 16S rRNA sequence analysis revealed a high bacterial diversity. Most sequences retrieved by PCR with a general bacterial primer set were affiliated with Bacteroidetes, Gammaproteobacteria, Deltaproteobacteria and the Pirellula cluster of Planctomycetales. Fluorescence in situ hybridization (FISH) and slot-blot hybridization with group-specific rRNA-targeted oligonucleotide probes were used to characterize the microbial community structure over depth (0–12 cm) and seasons (March, July, October). We found high abundances of bacteria with total cell numbers up to 3×10⁹ cells ml⁻¹ and a clear seasonal variation, with higher values in July and October versus March. The microbial community was dominated by members of the Planctomycetes, the Cytophaga/Flavobacterium group, Gammaproteobacteria, and bacteria of the Desulfosarcina/Desulfococcus group. The high abundance (1.5×10⁷–1.8×10⁸ cells ml⁻¹ accounting for 3–19% of all cells) of presumably aerobic heterotrophic polymer-degrading planctomycetes is in line with the high permeability, deep oxygen penetration, and the high rates of aerobic mineralization of algal biomass measured in the sandy sediments by de Beer et al. (2005). The high and stable abundance of members of the Desulfosarcina/Desulfococcus group, both over depth and season, suggests that these bacteria may play a more important role than previously assumed based on low sulfate reduction rates in parallel cores (de Beer et al., 2005).     

Summer feeding strategy of the little auk (Alle alle) from Bjørnøya, Barents Sea

Summer food of the little auks nesting on Bjornoya consisted of large copepods, decapod larvae and pelagic amphipods. Food items of 4–6?mm constituted the most common prey size fraction. This prey size range appears to be optimal (most profitable) with regard to the balance between mean individual mass and density of items in the surface layers of the sea. Little auks from Bjørnøya only sporadically take the abundant copepod Calanus finmarchicus (2–3.5?mm in length) but select the much less abundant and larger Calanus glacialis (3–6?mm).RID="ID=" Acknowledgements The authors would like to thank Dr. Monika Normant from the University of Gdansk for her assistance with caloric measurments, and Lech Illiszko and Adam Wajrak for their help with the fieldwork on Bj&;oslash;rn&;oslash;ya.RID="ID=" Correspondence to J. M. We&;cedil;s&;lstrok;awski     

The relationship between diatoms and surface water quality in the Høylandet area of Nord-Trøndelag, Norway

Although the ecological effects of surface wateracidification are now well researched, factorscontrolling the abundance and occurrence of aquaticorganisms in unpolluted acid-sensitive systems arepoorly known. The Høylandet region in central Norwayexperiences relatively low levels of atmosphericpollution and its surface waters, although acid, arenot significantly acidified. Hence lakes and streamsin this region were selected to study the influence ofwater chemistry on diatom algae. Relationships betweenthe two were explored using the multivariate techniqueof canonical correspondence analysis (CCA). Theprincipal water chemistry variables influencingspecies composition of periphytic diatoms were foundto be pH and water colour. Furthermore, therelationship between species abundance and pH wassufficiently strong to enable reconstruction of wateracidity from diatom data. Establishing the nature ofaquatic communities in atmospherically clean butgeologically sensitive regions is an important meansof identifying control systems against which therecovery of acidified lakes in polluted regions can beassessed. The Høylandet region has the potential toprovide a Europe-wide control system of this naturebut much further work is required to follow up andextend the results of this preliminary study.     

Effects of the severe winter 1995/96 on the biological oceanography of the Sylt-Rømø tidal basin

Water temperature, salinity and precipitation, micronutrients (N, P, Si) and chlorophyll a concentrations in the Sylt-R?m? tidal basin (German Bight) deviated between the early 1990s, with mild winters, and the years 1996–1997 with a severe winter and a moderate winter. As a consequence of low temperature, offshore winds and low precipitation in the severe winter 1995/96, salinity peaked in February 1996 and nitrate concentrations were low. The latter further decreased in March as chlorophyll a peaked with an exceptional bloom of the diatom Odontella aurita, probably triggered by low water temperature. Winter temperatures and spring chlorophyll a in the Sylt-R?m? tidal basin correlate well with the climatic North Atlantic Oscillation index. Received in revised form: 7 May 2001 Electronic Publication     

Structural and functional studies on ø29 DNA polymerase

TheBacillus subtilis phage ø29 DNA polymerase, involved in protein-primed viral DNA replication, contains several amino acid consensus sequences common to other eukaryotic-type DNA polymerases. Using site-directed mutagenesis, we have studied the functional significance of a C-terminal conserved region, represented by the Lys-X-Tyr (“K-Y”) motif. Single point mutants have been constructed and the corresponding proteins have been overproduced and characterized. Measurements of the activity of the mutant proteins indicated that the invariant Lys and Tyr residues play a critical role in DNA polymerization. Interestingly, substitution of the invariant Lys either by Arg or Thr, produced enzymes with an increased or a largely reduced, respectively, capability to use a protein as primer, an intrinsic property of TP-priming DNA polymerases. On the other hand, the viral protein p6, which stimulates initiation of ø29 DNA replication by formation of a nucleoprotein complex at both DNA replication origins, increased (about 5-fold) the insertion fidelity of ø29 DNA polymerase during the formation of the TP-dAMP initiation complex. We propose a model in which the special strategy to maintain the integrity of the ø29 DNA ends, by means of a “sliding-back” mechanism, could also contribute to increase the fidelity of ø29 DNA replication.     

Zooplankton in Lake Atnsjøen 1985–1997

The aim of this paper is to study long-term changes in the zooplankton of a subalpine locality unaffected by direct anthropogenic disturbances. The material has been collected during the period 1985–1997; since 1988 a standardised sampling program has been followed, with five sampling dates during the ice free period (June–October) at three fixed stations. Altogether 17 species of Rotatoria, 9 species of Copepoda and 11 species of Cladocera were recorded. Of these 10 species of Rotatoria, two species of Copepoda and five species of Cladocera occur regularly in the plankton. Polyarthra vulgaris dominate among the rotifers together with Kellicottia longispina and Conochilus unicornis. The crustacean community is dominated by the copepod Cyclops scutifer, and the cladocerans Bosmina longispina, Holopedium gibberum and Daphnia longispina. The cladocerans Bythotrephes longimanus, Polyphemus pediculus,and the copepodsArctodiaptomus laticeps and Heterocope saliens all occur regularly, but at low densities. The zooplankton density is low in May/June and peaks in August and September, but the timing of maximum densities varies from year to year. By numbers, the rotifers strongly dominate with densities 10–15 times higher than the crustaceans. The annual maximum density (rotifers plus crustaceans) ranged from 50 ind. l^?1 (1985, 1988) to 450 ind. l^?1 (1995). Mean density is about 140–150 ind. l^?1. By biomass (dry weight), the cladocerans constitute 60%, while the copepods and rotifers constitute 30% and 10% of the zooplankton, respectively. The annual maximum has varied between 70 and 260 μg dw l^?1, with 170 μg dw l^?1 as the mean level. C. scutifer usually has a one-year lifecycle without diapause, but a small fraction of the population has a two-year lifecycle. The life cycle in 1989 and 1990 differed strongly from the other years. The life cycles of B. longispina, D. longispina and possibly also H. gibberum and A. laticeps, indicate two generations during the summer. H. gibberumandH. saliens pass the winter as resting eggs. The other crustacean species, except C. scutifer, pass the winter mainly as resting eggs, but all have a small winter population in the water mass. C. scutifer is the only species without resting eggs. The vertical distribution normally shows highest density between 5 and 10 m depth. However, during some periods maximum density is observed close to the surface, while at other times it is seen deep in the hypolimnion. The vertical distribution is most pronounced when the thermocline is sharp, and less pronounced during the full circulation in autumn. The vertical migration may also be pronounced, especially in B. longispina, with high density near the surface during the night. The vertical migration is less pronounced among the rotifers and copepods. The degree of vertical migration varies with temperature and food conditions. There is little variation from year to year in species composition, but large variation in species dominance, seasonal development, population density, and vertical and horizontal distribution during the sampling period. Variations in temperature, food condition, predation, and water through-flow are possible causes for the observed differences between the years. Input of allochthonous material is especially important. However, no clear correlation have been found between the development of the plankton community and these environmental factors. Hence, these interactions are complex and multifactorial.     

Ólavsøka: The faroese national holiday*

In many cultures with male‐dominated religions, women are subject to illnesses which are attributed to spirit‐possession. Two main alternative therapies are usually available. Treatment is effected either by exorcism, or by domesticating the spirit ‐ a process which de Heusch calls ‘adortism’. In the latter case, women are recruited through illness into female‐centred ‘cults of affliction’, regarded as superstitious and subversive by men, who try to prevent their wives from becoming involved in these cults, preferring exorcism as therapy. Exorcism thus becomes an instrument of male power in the struggle to control women's incipient religiosity. The paper examines the interplay of exorcism and adorcism in relation to gender in Christian, Muslim and Buddhist settings. It concludes by considering the implications of women as well as men practising exorcism, and suggests that the consequences of the formal distinction between exorcism and adorcism may not always be as sharply opposed as appears at first sight.     

Some physical and chemical characteristics of Lake Atnsjøen

The physical and chemical characteristics of the dimictic, ultraoligotrophic, and subalpine Lake Atnsjøen are described based on data from the period 1985–2001. The temperature stratification of the lake is weakly developed, with the thermocline at about 10 m depth. The surface temperature during summer is usually lower than 14–15?°C. The Secchi disk transparency is normally higher than 8–10 m in summer and autumn, but can be as low as 4.3 m during spring. The pH is about 6.0, and the specific conductivity about 1.0 mS m^{? 1}. The dominating cation and anion are Ca (≈0.8 mg l^?1 or 42 μeq l^?1), and SO₄ (≈1.5 mg l^?1 or 33 μeq l^?1), respectively. The concentration of bicarbonate (HCO₃, μeq l^?1) is sometimes lower, sometimes higher than that of SO₄.     

In search of the Bølling-Oscillation: a new high resolution pollen record from the locus classicus Lake Bølling,Denmark

Vegetation History and Archaeobotany - In a paper from 1942 Johannes Iversen described a warm phase prior to the Allerød warming from lake Bølling in western Denmark and thereby extended...     

Surface water chemistry characteristics in the Lake Storgrønningen drainage area, Høylandet, during periods of high and low discharge

The surface water chemistry of Høylandet has beenstudied by performing two synoptic surveys, duringhigh runoff in the autumn of 1986 and during a lowflow period in the summer of 1988. Based on watersamples of up to 38 chemical variables from 75 sites,analyses show considerable variation in the chemicalcomposition. There is a strong altitude gradient, i.e.very dilute poorly buffered waters dominate at higherelevations near the timberline while progressivelyhigher salt content and alkalinities arecharacteristic at lower altitudes more dominated byforests. The influence of mires is less pronounced.The overall water quality is of oligotrophic naturewith low concentrations of strong acid anions andmetals known to be enriched under acidifiedconditions. The natural pH gradients are considerablebut with no indication of anthropogenic acidification.The data provide little support for the hypothesisthat in-catchment production of organically derivedacidity leads to acid runoff, which in thesecatchments appears compensated by increasedweathering. The findings are in general accordancewith other Høylandet catchment studies. It isconcluded that this area may serve as a representativepristine surface runoff analogue for catchmentscurrently affected by atmospheric deposition of strongmineral acids.