Svalbard: projects/activities

In a context of global change, arctic ecosystems are exposed to deep modifications not only of the biology and ecology of endemic species but also of the interactions they may have with an increasing number of introduced species. This project attempts to assess in Svalbard, the impacts of global changes on aphids. These phytophagous insects are particularly relevant organisms for studies on the effects of global warming and biological invasion because 1) of their extreme sensitivity to micro- and macro- changes due to their spectacular rate of increase and phenotypic plasticity and 2) of their colonizing capacity conferred by their parthenogenetic mode of reproduction and their dispersal potential

The aim of this programme was to study the physiological and behavioural adaptations to the incubation fast in the female eider. This leads to study fundamental questions about three complementary field researches described below. 1. Evolutionary and ecological approaches: energetic costs of reproduction during incubation In long-lived birds as Eider, there must be trade-offs between the energy allocated in growth and in reproduction. Therefore, individuals develop different reproductive strategies in relation with biotic and non biotic factors to maximize their fitness. Among factors tested, we will first measure the effects of animal density on female reproductive success. Additionally, we will measure, thanks to genetic tests, 1) the characteristics of eider populations (dispertion) by comparing birds originating from several islands and several locations on the same island, 2) the frequency of intra-specific nest parasitism and 3) extra-pair copulations to link these events with female behavioural decisions. To link reproductive effort with female immunocompetence, we will then perform PHA (phytohaemagglutinine) skin tests at different stages of the incubation period. Finally, we will perform clutch reductions at different stages of the incubation period in order to highlight decision rules controlling nest desertion in females. 2. Physiological and ecological approaches: parental investment in reproduction We will also focus on the implication of prolactin and corticosterone in the control of parental decision at the hatching stage. Implantation of exogenous hormones will be done on nesting birds to evaluate the respective role of these two hormones in the control of parental decisions in eiders. Parental investment in incubation can be regulated by the reproductive value of the clutch size. To further understand the mechanism underlying nest desertion, we will measure the induced-changes in prolactin and corticosterone concentrations after clutch size manipulation overall the incubating period. 3. Physiological approach: regulation of body fuel utilization during fasting The aim will be to study the mechanisms of the regulation of body fuel utilization and energy expenditure during fasting. For this purpose, the ability of eider duck to withstand long periods of starvation will be studied by measuring the variations in plasma of major substrate concentrations (as index of lipid or protein breakdown) and hormones (e.g., leptin, glucagon, corticosterone, T3, ...). The study of duck’s adaptation to extended fasts occurring at specific stages of their life might help to understand important underlying mechanisms, such as reduction in energy expenditure, long-term regulation of body fat storage and mobilization, as well as long-term control of food intake.

The aim of this research program is to examine the response of animal populations to environmental variability at different spatial scales. We attempt to determine how individuals respond to the spatial heterogeneity of their environment, and what are the consequences of this response for the dynamics of subdivided populations. Specifically, we consider an ecological system involving biotic interactions at three levels: seabirds, their tick _Ixodes uriae_, and the microparasite _Borrelia burgdorferi_ sensu lato (Lyme disease agent). Colonies of seabirds represent discrete entities, within and among which parasites can circulate. Our previous work on this system in the norwegian arctic has enable us to show that (1) host dispersal can be affected by local conditions, (2) seabird tick populations are specialised among different host species, namely between sympatric kittiwakes _Rissa tridactyla_ and puffins _Fratercula arctica_, (3) in the kittiwake, females transmit antibodies against _Borrelia burgdorferi_ when their chicks have a high probability to be exposed to the tick vector. We propose to combine different approaches, incorporating field surveys and experiments and population genetic studies (of hosts and parasites), in order to better understand the role of local interactions and dispersal in the dynamics of such a system. The research program implies collaborations with researchers from other french groups, as well as with Canadian (Queen’s University) and Norwegian colleagues (from NINA and the University of Tromsø).

The 2003 field activity will be mainly dedicated to coring activity which includes: 1. the sampling of snow and ice cores from a Ny-Ålesund nearby glacier (midre Lovenbreen). 2. the collection of near coast (Kongsfjorden) and lakes sediments (maximum under pack depth 30 m). Sampling collection of ice and sediment cores will be performed using a portable, electric operated, sampling corer. The transport of all materials up to each sampling station should be performed with snowcats.

The high Arctic contains delicate, relatively pristine ecosystems that are increasingly subject to exported aerial pollution (e.g. nitrogen) and higher than average climatic temperature change. Together these factors may potentially change important biogeochemical processes (e.g. the cycling of carbon and nitrogen) and ecosystem dynamics. This project involving the University of Nottingham, The British Geological Survey and IACR Rothamsted is now entering its second field season. The project concentrates on the release and the subsequent fate of N, entering the tundra ecosystem, as a pulse during the spring thaw. The questions we propose addressing are (i) how important is this event in transferring enhanced N deposition to tundra ecosystems, and how much is lost as run-off to lacustrine and inshore marine environments, (ii) how does enhanced N affect the carbon cycle (i.e. plant growth, decomposition processes) and (iii) what is the impact on soil N mineralizationimmobilization dynamics. Two plot experiments have been set up at contrasting vegetation sites around Kongsfjorden (Brandalspyntyn and Ny-London). We have simulated the release of N from the snowpack by applying 15N label as the snow has melted. An accurate audit regarding the fate of this snowpack N can then be made (i.e. does it remain in the soil, enter the tundra flora and soil microbiology or is it lost from the system). In addition, using techniques for combined 18O+15N analysis of nitrate, we can distinguish between atmospheric- and soil-derived nitrate. This will allow us to assess and source losses of N from the tundra during the brief summer growing season. These complementary approaches will provide a quantitative understanding of the fate of deposited N in the pristine Arctic environment. The overall aim will be to parameterize an N-flux model for this important ecosystem.

Effects of UV-B radiation on microbial communities in Kongsfjorden in relation to metal and dissolved organic matter availabillity.

To investigate arctic foxes physiological adaptations to life at high latitudes. Resting and running metabolic rates, body weight, food intake, body core temperature, heart rate, and blood parameters were examined during different seasons and during periods of food deprivation.

Biological nitrogen fixation by cyanobacteria is a key process for productivity in terrestrial Arctic ecosystems and the activity is dependent of size and diversity of cyanobacterial populations. Changes in biodiversity after pertubations of different types of habitats simulating climatic changes or other antropogenic effects will be studied by molecular methods and correlated to variations of nitrogen fixation activity.

The structure and role of the cyanobacterial communities that colonise bare soils and fix nitrogen in the arctic ecosystem will be studied. The planned activities will focus on the isolation, identification and characterisation of cyanobacteria from arctic habitats and on the changes of the cyanobacterial community along a transect from a retreating glacier front to a more stable habitat characterised by the presence of mature vegetation. For these purposes, a polyphasic approach encompassing microbiological, morphological and molecular techniques will be applied to environmental samples and isolated cultures. The obtained results will give new insights on the diversity and role of nitrogen fixing cyanobacteria in the arctic and, in more general terms, on ecosystem development under changing climatic conditions.

To evaluate temporal variation in arctic fox numbers and their food resourses in the Kongsfjorden area. The number of foxes captured per 100 trap-days are used as an index of fox density termed "Fox Capture Index". The observations of denning activity i.e. observation of number of arctic fox litters and litter size at den are termed "Fox Den Index" as a second index of fox abundance. A third index is termed "Fox Observation Index". This index is based on both observations of adult foxes seen away from breeding dens pr 100 h field work and reports on request from scientists and local people on observations of adult foxes during summer. In addition, reports on observation of fox tracks in the study area were collected in 1990-2001 as a fourth index, which were called "Fox Track Index". The field census are conducted for 10 days starting at the end of June. All dead foxes in the area should be collected.

The aim of this programme will be to study the mechanisms of the regulation of the body fuel utilizon and energy expenditure during fasting

Energy allocation

Parental effort, the extra energy expenditure above maintenance levels devoted to the care of affspring, has been postulated to incur a fitness cost.

The objectives of this project is to study the effect of environmental stochasticity on the Svalbard reindeer population dynamics, nad further evaluate how this may affect reindeer-plant interactions.

The objective of the planned work with arctic higher plants is to study the range of adaptation of photosynthetic metabolism, of antioxidative and sun screen compounds in a cold and reduced UV-B climate in comparison of data already raised from high alpine plants, which live partially under stronger cold and under different light regimes, especially higher UV-B. Further, the ultrastructure of leaf cells will be studied to clear, whether adaptations found in some high alpine plants occur similarly in arctic plants, and to connect such cytological results with metabolic functions. An additional comparison will be made with snow algae from Svalbard compared to those harvested on high alpine snow fields. It is the advantage of the planned work, that a number of investigations ranging from ultrastructural studies over different aspects of photosynthesis to assays of UV-B sensitive compounds and antioxidants will be conducted mostly with measurements and sample collection in the field during the same experimental day at one place. Therefore we expect a good connection of the data raised, back to the plant system and expect a much broader description of vitality and adaptation under the current conditions.

The polar pteropod Clione limacina is characterised by high quantities of lipids with ether components (1-O-alkyldiacylglycerol=DAGE) in combination with odd-chain fatty acids. It is unknown why Clione and probably other pteropods have specialised in this manner. Furthermore the precursor of the biosynthesis of these compounds is still unknown. Therefore samples of Clione limacina and its only prey Limacina helicina will be collected by using plankton nets from small boats. The species will be kept in aquaria and feeding experiments with both species and food of different composition and nutritional value are planed.

Benthic macroalgae communities of the arctic ocean provide habitat, protection, nursery and nutrition to a large number of invertebrates. In contrast to temperate and tropical regions the basic ecological interactions between zoo- and phytobenthos of the Arctic are little understood. Therefore this project for the first time investigates biological and chemical interactions between invertebrates and macroalgae on Spitsbergen/Svalbard (Koldewey Station) with special emphasis on defense mechanisms against grazing pressure. Initial diving-investigations will map the invertebrate fauna which is associated with the macroalgae; the following feeding-experiments with herbivorous animals aim to selectively identify generalists, generalists with preference or specialists. Additional bioassays serve to reveal structural and/or chemical properties of those plants, which affect a specific impact on the grazing of herbivores. Our investigations on the chemical protection of the algae against grazing focus on the basic mechanisms and the chemical structure of potent secondary metabolites carried out in cooperation with natural product chemists.

Succession of communities and individual growth of benthic invertebrates are more or less unknown in polar waters, but nevertheless are the basic parameters of understanding the benthic sub-ecosystem, delivering data for modelling and prediction of the system´s development. Three localities, two in the Antarctic and one in the Arctic, the Kongsfjord in Spitsbergen, have been choosen as investigation localities. Hard and soft substrates, which will be sampled in regular intervalls during the duration of the project, will be deployed at different depths. The analysis includes species composition, species growth and, with respect to soft substrates, sediment parameters.