Institutt for arktisk og marin biologi

Parasite communities of two three-spined stickleback (Gasterosteus aculeatus) populations : effects of a local-scale host introduction?

Jakobsen, Jonas — Mon, 31 Oct 2011 23:00:00 GMT

Jakobsen, Jonas
The introduction of new hosts into new habitats can bring along hitchhiking parasites, i.e. parasites being introduced with the host. This in particular can be an important dispersal mechanism for autogenic parasites that are otherwise restricted by the natural movement of their fish hosts. In this study, the effect of a local host introduction on the parasite communities of three-spined sticklebacks in two subarctic lakes, was examined by comparing the parasite communities of the “introduced” (Takvatn), versus that of the “founder” (Sagelvvatn) population. Seasonal variation and inter-lake differences in abundance was also integrated in the study. The study revealed great similarity between the parasite communities du to similar ecosystems, close geographical proximity, and the facts that the only two autogenic stickleback specialists present in the systems had been introduced with its host. The subtle differences in parasite species richness were explained by accidental infections of parasites of sympatric fish species.

Bioaccumulation of phenanthrene and benzo[a]pyrene in Calanus finmarchicus

Jensen, Louise Kiel — Fri, 31 Dec 2010 23:00:00 GMT

Jensen, Louise Kiel; Jæger, Iris; Honkanen, Jani O.; Caroll, JoLynn
With petroleum exploration and development expanding in the Arctic (AMAP, 2007) there is a need to obtain additional information on the ecotoxicology of Arctic organisms. Here we perform 192 hr laboratory exposure experiments on the keystone Arctic zooplankton species, Calanus finmarchicus. We trace the accumulation and depuration of two polycyclic aromatic hydrocarbons (PAHs): phenanthrene and benzo[a]pyrene (B[a]P) using 14C labeled PAH compounds. Copepods were not fed during the experiment, limiting uptake to diffusion processes alone. The lighter PAH compound, phenanthrene, accumulated rapidly in C. finmarchicus, reaching steady state within 96 h. The heavier PAH compound, B[a]P, accumulated more slowly and steady state was not reached within the 192 h exposure period. As expected, the bioconcentration factor (BCF) for B[a]P was higher than for phenanthrene in accordance with a higher octanol/water partition coefficient for B[a]P (log Kow = 6.04) compared to phenanthrene (log Kow = 4.53). However, for both compounds, log BCF was lower than log Kow that may indicate active biotransformation and excretion of the selected PAH compounds. These findings on the bio-uptake kinetics for petroleum hydrocarbons are essential for evaluating the potential consequences of an oil spill in the Arctic.
This is the submitted manuscript version of the paper. This paper is part of Louise Kiel Jensen's doctoral thesis, which is available in Munin at http://hdl.handle.net/10037/3794

Spatial and temporal variation in abundance of willow ptarmigan Lagopus lagopus and rock ptarmigan Lagopus muta in Finnmark county, Norway : evaluation of methods for population monitoring

Bolstad, Johannes — Fri, 14 May 2010 22:00:00 GMT

Bolstad, Johannes
Abstract: Sustainable harvesting requires reliable quantitative estimates of pre-harvesting population size, however, within low management budgets, good quality predictions are often difficult to obtain. For the popular game species willow ptarmigan (Lagopus lagopus) estimates of population density or relative indices are often obtained from line transect surveys, however, the quality of estimates could be sensitive to low sampling effort. Additional ptarmigan population data is hunting statistics, but the potential lack of convergence between population density and hunting bag remains a concern. The sympatric rock ptarmigan (Lagopus muta) is commonly given much less management attention, and the species is often arbitrarily expected to show synchronised dynamics with willow ptarmigan. In this paper we evaluate different population indices obtained from willow ptarmigan line transects surveys in late summer, and catch reports of subsistence snare trapping in late winter, and specifically assess these indices’ ability to predict subsequent ptarmigan hunting bags in eight municipalities in northernmost Norway. We use line transect data from 6–7 years of varying monitoring effort, snare trapping data from between 6 and 12 years in different municipalities, and hunting statistics from 7–8 years in all municipalities. Generalised linear mixed-effect models indicated that only crude predictions of the subsequent willow ptarmigan hunting bags could be made from the line transect estimates under the current management regime. The snare trapping index made only a minor improvement of the prediction, and although the potential effects varied between municipalities, its inclusion as a predictor is not generally recommended in future ptarmigan management. The rock ptarmigan hunting bags could not be predicted by any of the available pre-harvesting indices. Variance component analyses revealed pronounced lack of systematic variation in all indices for both ptarmigan species, consequently any prediction of subsequent hunting bag outcome, should be highly conservative. Although we did not find clear tendencies of better predictions in municipalities with higher line transect effort, we suspect that the monitoring effort needed to provide useful pre-harvest indices is highly underestimated in the current management regime. Potentially unknown ptarmigan population processes and an elevated hunting pressure, should encourage management to increase, knowledge-based ptarmigan monitoring in the future. Key words: willow ptarmigan; rock ptarmigan; sustainable harvesting; population density indices; line transect; snare trapping statistics; hunting statistics; population dynamics; population monitoring; game management; arctic ecosystems; Finnmark; Norway.

Seasonal microbial processes in a high-latitude fjord (Kongsfjorden, Svalbard) : I. Heterotrophic bacteria, picoplankton and nanoflagellates

Iversen, Kriss Wenche Rokkan — Fri, 31 Dec 2010 23:00:00 GMT

Iversen, Kriss Wenche Rokkan; Seuthe, Lena
Temporal dynamics of the microbial food web in the Barents Sea and adjacent water masses in the European Arctic are to a large extent unknown. Seasonal variation in stocks and production rates of heterotrophic bacteria and phototrophic and heterotrophic picoplankton and nanoflagellates was investigated in the upper 50 m of the highlatitude Kongsfjorden, Svalbard, during six field campaigns between March and December 2006. Heterotrophic bacteria, picoplankton and nanoflagellates contributed to ecosystem structure and function in all seasons. Activity within the microbial food web peaked during spring bloom in April, parallel to low abundances of mesozooplankton. In the nutrient-limited post-bloom scenario, an efficient microbial loop, fuelled by dissolved organic carbon from abundant mesozooplankton feeding on phytoplankton and protozooplankton, facilitated maximum integrated primary production rates. A tight microbial food web consisting of heterotrophic bacteria and phototrophic and heterotrophic picoplankton and nanoflagellates was found in the stratified water masses encountered in July and September. Microbial stocks and rates were low but persistent under winter conditions. Seasonal comparisons of microbial biomass and production revealed that structure and function of the microbial food web were fundamentally different during the spring bloom when compared with other seasons. While the microbial food web was in a regenerative mode most of the time, during the spring bloom, a microbial transfer mode represented a trophic link for organic carbon in time and space. The microbial food web’s ability to fill different functional roles in periods dominated by new and regenerated production may enhance the ecological flexibility of pelagic ecosystems in the present era of climate change.
This article is part of Lena Seuthe's doctoral thesis, which is available in Munin at http://hdl.handle.net/10037/3777

Microbial processes in a high-latitude fjord (Kongsfjorden, Svalbard) : II. Ciliates and dinoflagellates

Seuthe, Lena — Fri, 31 Dec 2010 23:00:00 GMT

Seuthe, Lena; Iversen, Kriss Wenche Rokkan
The composition and ecological role of ciliates and dinoflagellates were investigated at one station in Kongsfjorden, Svalbard, during six consecutive field campaigns between March and December 2006. Total ciliate and dinoflagellate abundance mirrored the seasonal progression of phytoplankton, peaking with 5.8 9 104 cells l-1 in April at an average chlorophyll a concentration of 10 lg l-1. Dinoflagellates were more abundant than ciliates, dominated by small athecates. Among ciliates, aloricate oligotrichs dominated the assemblage. A large fraction ([60%) of ciliates and dinoflagellates contained chloroplasts in spring and summer. The biomass of the purely heterotrophic fraction of the ciliate and dinoflagellate community (protozooplankton) was with 14 lg C l-1 highest in conjunction with the phytoplankton spring bloom in April. Growth experiments revealed similar specific growth rates for heterotrophic ciliates and dinoflagellates (\0–0.8 d-1). Food availability may have controlled the protozooplankton assemblage in winter, while copepods may have exerted a strong control during the post-bloom period. Calculations of the potential grazing rates of the protozooplankton indicated its ability to control or heavily impact the phytoplankton stocks at most times. The results show that ciliates and dinoflagellates were an important component of the pelagic food web in Kongsfjorden and need to be taken into account when discussing the fate of phytoplankton and biogeochemical cycling in Arctic marine ecosystems.
This paper is part of Lena Seuthe's doctoral thesis, which is available in Munin at http://hdl.handle.net/10037/3777

Næringsøkologi og ontogenetisk nisjeskift hos ørret og røye

Moe, Are Andreassen — Mon, 31 Oct 2011 23:00:00 GMT

Moe, Are Andreassen
Ressursdeling og ontogenetisk nisjeskift ble undersøkt hos sympatrisk ørret og røye ved å inkludere stabile karbon- og nitrogenisotoper for å få et mer langtidsintegrert bilde av fiskens næringshabitat og diettbruk. I begge innsjøene benyttet ørreten seg primært av littoralsonen, mens røya tok i bruk alle tilgjengelige habitater. Det ble funnet en tydelig ressursdeling i diett mellom ørret og røye i begge innsjøene. Både diettanalysene og δ13C` viste at ørreten primært benyttet seg av littorale næringsemner i begge innsjøene. Ved økende lengde hos ørret, økte både andelen stingsild i dietten og ørretens trofiske posisjon beregnet ut i fra δ15N. Det var primært de minste lengdegruppene av røye som benyttet seg av profundale næringsemner, som støttes av både diettanalyser og stabile isotoper i begge vann. Både δ13C` og δ15N verdier viser at røya i Sagelvvatn beitet på profundale næringsemner, men med økende lengde gikk de over til pelagiske næringsemner. Det samme mønsteret ble funnet i Takvatnet, men δ13C`verdier gir indikasjoner på at profundale næringsemner utgjorde en mindre andel av dietten hos de minste lengdegruppene. Det konkluderes med at forskjellene i ressursdeling i habitat og diett både innen røye og ørret populasjoner og mellom ørret og røye populasjoner i stor grad kan forklares ut i fra interaktiv segregering mellom artene og ørretens konkurransefortrinn i som bunndyrspiser i littoralsonen.

Functional analysis of microRNA 840 in Arabidopsis

Zhong, Zhijian — Sun, 15 May 2011 22:00:00 GMT

Zhong, Zhijian
Three mechanisms have been implicated for plant microRNAs (miRNAs) to regulate gene expression, i.e. directing target RNA cleavage, transcriptional silencing and translational repression. A great number of target genes of plant miRNAs were predicted using different algorithms and verified through experimental methods. In the present work, one miRNA from Arabidopsis, microRNA 840 (miR840) was initially analyzed through the high-through put sequencing and bioinformatic method (Rajagopalan et al., 2006). MiR840 expresses from the complementary strand of its predicted target gene, AtWhirly3. AtWhirly3 encodes a homolog of the potato transcriptional regulator p24. MiR840 is located between 2 genes, At2g02740 (Whirly 3, Why 3) and At2g02750 (Pentatricopeptide Repeat Protein, PPR). Whirly 3 protein belongs to the Whirly protein family which is one of the main interesting topics in our group. Understanding the potential regulative function of miR840 related to Whirly 3 gene is important to deeply analyze the Whirly 3 protein. Searching the TAIR (http://www.arabidopsis.org) and TIGR (http://plantta.jcvi.org), the two databases give different annotation versions for this AtWhirly3 gene, differing at the length of the 3’ untranslated region. According to the annotation from TAIR, the target of miR840 is only at the 3’ untranslated region (3’ UTR) of Why 3 gene, so this means miR840 only down-regulate the Why 3 gene. But the information from TIGR gives another annotation, Why 3 gene (At2g02740) and its neighbor gene, a PPR gene (At2g02750) overlap with their 3’ UTR where the target site of the miR840 is. This means the miR840 may also be able to down-regulate both the Why 3 and PPR gene, depending on what annotation you take. Therefore experimental analysis is necessary to determine the miR840 target. My master project here is to perform the biological experiments for analyzing the function of miR840. To verify the target genes and study the biological function of miR840. 4 vectors have been firstly constructed and then introduced into Arabidopsis thaliana by Agrobacterium-mediated transformation (1: overexpressed precursors of miR840; 2: overexpressed mutated miR840 target for directing the miR840 lost its normal function; 3: overexpressed Why 3; 4: overexpressed PPR). The mutated miR840 was constructed by the mechanism of target mimicry which through artificial insertion of a mismatch-loop into the cleavage site at the miRNAs target, for making mutated miRNAs targets. The mutated target sites will direct the miRNAs cannot cleave their targets (miRNAs lost their normal function). The expression level of the transgenic plants will be analyzed, the changes of the expression levels observed in the transgenic plant lines could imply the possible role of miR840. The subcellular location of the PPR (At2g02750) protein which is still unknown yet, so the bioinformatic method was used to predicted its subcellular location.

Peripheral heterothermia in reindeer (Rangifer tarandus tarandus)

Olsson, Elin Anita Maria — Sun, 15 May 2011 22:00:00 GMT

Olsson, Elin Anita Maria
Reindeer (Rangifer tarandus tarandus) inhabit the Arctic and have evolved adaptions to meet the climatic challenges in this region. Peripheral heterothermia, which is a heat conserving mechanism in homeotherms during cold exposure, is well documented in the reindeer and manifests itself in tissue temperatures in the extremities well below 10°C. It is, however, unknown whether peripheral heteothermia in reindeer requires efficient vascular counter-current heat exchange, or is simply a result of reduced blood flow to the extremities. Vascular corrosion casts, x-ray pictures, dissections and electron microscopy did not reveal any counter-current rete in the front legs, but the vascular anatomy, with arteria brachialis and vena brachialis running in intimate contact with each other for the full length of the leg, still seems to allow quite efficient counter-current heat exchange. Recordings of brachial blood flow and subcutaneous temperature (Tsc) in the front legs of winter insulated reindeer subjected to ambient temperatures (Ta) of 20°C, -10°C and -30° suggest that the initial drop in Tsc seen in reindeer when exposed to moderate cold (-10°C) is primarily the result of use of a circulatory pattern enabling counter-current heat exchange, while decreasing blood flow appears to be a secondary mechanism when Ta falls further towards -30°C.

Å råde eller ei? : holdninger til allemannsretten, vern og forvaltningsnivå blant tilreisende og lokale i fire norske verneområder

Borge, Eivind Høstmark — Tue, 31 May 2011 22:00:00 GMT

Borge, Eivind Høstmark
Gjennom de siste 20-30 år har det vært en desentraliseringstrend i forvaltningen av verneområder med mål om økt deltagelse og større bruk av lokal kunnskap. Trass gode intensjoner har desentraliseringsforsøkene hatt blandet suksess, blant annet grunnet et forenklet syn på lokalsamfunnet som en homogen enhet. For å belyse dette ble det i 2009 og 2010 gjennomført to spørreundersøkelser i fire norske verneområder, med hensikt å undersøke tilknytning til området samt holdninger til allemannsretten, vern og forvaltningsnivå blant tilreisende (N=88), lokale uten rettigheter (N=161) og lokale med rettigheter (N=97). Tilknytning og støtte til allemannsretten var generelt stor blant gruppene, men rettighetshaverne skilte seg ut ved å være sterkest tilknyttet området, samt mer skeptisk til allemannsretten. Lokale ønsket større rettigheter til bruk enn tilreisende. Tilreisende var svært positive til vern, mens lokalbefolkningen viste større variasjon, med rettighetshaverne som mest negative. Nasjonale miljømyndigheter ble hovedsakelig støttet av tilreisende grunnet objektivitet og frykt for kortsiktige økonomiske interesser blant lokalbefolkningen. Lokale, særlig rettighetshaverne, sluttet opp om lokale miljømyndigheter grunnet lokal kunnskap og tradisjon. At lokalbefolkningen generelt var mer skeptisk til vern og nasjonal forvaltning viser en utpreget råderettsfølelse. Det var imidlertid stor heterogenitet i holdningene, særlig blant de lokale, som bør tas hensyn til ved desentralisering.; During the last 20-30 years there has been a trend towards decentralization in the management of protected areas aiming at higher participation and use of local knowledge. These attempts have had mixed success, also due to a simplified view on local communities as homogeneous units. Two surveys were carried out in 2009 and 2010 among visitors (N=88), local residents without rights (N=161) and local residents with rights (N=97) in four Norwegian protected areas, with the objective to investigate place attachment and attitudes toward the public right of access, conservation and governance level. Place attachment and support for the public right of access were generally high, but residents with rights were stronger attached and more skeptical to the public right of access. Visitors were positive towards conservation, while local residents were more divided, especially the residents with rights. National governance was mainly supported by visitors with arguments of objectivity. The local residents, especially those with rights, supported local governance due to local knowledge and tradition. The fact that the local residents were more skeptical towards conservation and national governance shows a pronounced will to govern. However, especially the local communities displayed large internal heterogeneity, which must be taken into consideration in decentralization.

Site fidelity of Svalbard polar bears revealed by mark-recapture positions

Lone, Karen — Sat, 30 Apr 2011 22:00:00 GMT

Lone, Karen
The spring season is important to polar bears, since females with young cubs leave the maternity dens, ringed seal pupping creates a peak in prey availability, and it is the mating season. Understanding space- and resource use at this time is a key to understanding polar bear ecology. This study from Svalbard, Norway analyzed 348 measurements of spring-to-spring displacement from 220 polar bears obtained by mark-recapture sampling in the period 1987 – 2010 to assess whether the bears exhibit spring site fidelity. All age and sex classes of polar bears showed site fidelity when their movements were compared to a scenario of random movements between all capture locations. The median observed displacement for all bears was 43.0 km (bootstrapped 95% CI: 34.3 - 51.0 km), significantly smaller than the median potential displacement for random movements of 205.4 km (bootstrapped 95% CI: 205.1 - 205.6 km). Linear model analysis of all displacements showed that displacement length depended on both the age and sex of the individual. Subadult females had the longest displacements, followed by adult males and adult females. Consistent, precise site fidelity over time was only displayed by a subset of females. When only the first movement of each bear was included, the effects of age and sex in the linear model were less pronounced, and the difference between adult males (linear model estimate: 50.0 km) and adult females (40.7 km) was not significant. These findings support previous reports in the literature comparing movement patterns of males and females in other parts of the Arctic. Sufficient data to conclusively evaluate subadult movement patterns is still lacking. Overall similarities in site fidelity of adult males and females indicate that findings based on telemetry of females may be relatively representative of the whole adult Barents Sea population.