<p>Direct effects of the insecticide deltamethrin on zooplankton and benthic invertebrates werestudied during an attempt to eradicate signal crayfish. In accordance with earlier studies theresults of this investigation showed that deltamethrin is highly toxic for arthropods, whileRotifera, Oligochaeta and Mollusca have a higher tolerance. This study concludes thatRotifera in treated ponds coped with the actual concentration of deltamethrin used during theeradication attempt but that they probably got a different abundance and changed compositiondue to a new situation in competition and predation. Crustacean zooplankton totallydisappeared, but approximately a month after the treatment they began to recolonise. All thetaxonomical groups of arthropods drastically decreased in abundance, with total eliminationof the most sensitive groups. The concentration of deltamethrin was not higher than that somespecies of Hydracarina and Chironomidae survived.</p>

<p>The effects of prey size on prey choice in different cohorts of juvenile turbot (Psetta maxima)were studied in three nursery areas at Gotland. Prey length measurements showed that gobies(Gobiidae) increased in average length during the season, while mysids (Mysidae) did not.Experiments on predation capacity of different size classes of turbot on different size classesof prey showed that juvenile turbot easily can eat gobies that are up to two thirds of their ownbody length, while the body size of turbot does not have any effect on the predation capacityon mysids. Stomach content of 217 turbots, less or equal 35 mm, was analysed to see if therewas any change in diet during the season, but there was no significant change in diet. Theoverall conclusion was that early settlers most likely have an advantage due to greater accessof alternative prey.</p>

Programmed cell death (PCD) is a widely spread phenomenon among multi-cellular organisms. Without the deletion of cells no longer needed, the organism will not be able to develop in a predicted way. It is now belived that all cells have the capacity to self-destruct and that the survival of the cells is depending on the repression of this suicidal programme. PCD has turned out to show similarities in many different species and there are strong indications that the mechanisms running the programme might, at least in some parts, be evolutionarily conserced. PCD is a generic term for different programmes of cell destruction, such as apoptosis and autophagic PCD. An important tool to determine if a cell is undergoing PCD is the transmitting electron microscope. The aims of my study were to find out if, and in what way, the suspensor and endosperm in Vicia faba (Broad bean), which are short-lived structures, undergoes PCD. The endosperm degradation preceed the suspensor cell death and they differ to some extent ultrastructurally. The cell death occurs in both tissues about 13-14 days after pollination when the embryo proper is mature enough to support itself. It was found that both tissues are committed to autophagic PCD, a cell death characteristic of conspicuous formations of autophagic vacuoles. It was shown by histochemical staining that acid phosphatases are accumulated in these vacuoles but are also present in the cytoplasm. These vacuoles are similar to autophagic vacuoles formed in rat liver cells, indicating that autophagy is a widely spread phenomenon. DNA fragmentation is the first visible sign of PCD in both tissues and it is demonstrated by a labelling technique (TUNEL). In the endosperm nuclei the heterochromatin subsequently appears in the form of a network, while in the suspensor it is more conspicuous, with heterochromatin that forms large electron dense aggregates located close to the nuclear envelope. In the suspensor, the plastids develop into chromoplasts with lycopene crystals at the same time or shortly after DNA fragmentation. This is probably due to the fact that the suspensor plastids function as hormone producing organelles and support the embryo proper with indispensable growth factors. Later the embryo will be able to produce its own growth factors and the synthesis of these, in particular gibberelines, might be suppressed in the suspensor. The precursors can then be used for synthesis of lycopene instead. Both the suspensor and endosperm are going through autophagic PCD, but the process differs in some respects. This is probably due the the different function of the two tissues, and that the signals that trigger the process presumably are different. The embryo proper is probably the source of the death signal affecting the suspensor. The endosperm, which has a different origin and function, might be controlling the death signal within its own cell. The death might in this case be related to the age of the cell.

Visual signals, used for communication both within and between species, vary immensely in the forms that they take. How is it that all this splendour has evolved in nature? Since it is the receiver’s preferences that cause selective pressures on signals, elucidating the mechanism behind the response of the signal receiver is vital to gain a closer understanding of the evolutionary process. In my thesis I have therefore investigated how receivers, represented by chickens, Gallus gallus domesticus, respond to different stimuli displayed on a peck-sensitive computer screen. According to the receiver bias hypothesis, animals and humans often express biases when responding to certain stimuli. These biases develop as by-products of how the recognition mechanism categorises and discriminates between stimuli. Since biases are generated from general stimulus processing mechanisms, they occur irrespective of species and type of signal, and it is often possible to predict the direction and intensity of the biases. One of the results from the experiments in my thesis demonstrates that similar experience in different species may generate similar biases. By giving chickens at least some of the experience of human faces as humans presumably have, the chickens subsequently expressed preferences for the same faces as a group of human subjects. Another kind of experience generated a bias for symmetry. This bias developed in the context of training chickens to recognise two mirror images of an asymmetrical stimulus. Untrained chickens and chickens trained on only one of the mirror images expressed no symmetry preferences. The bias produced by the training regime was for a specific symmetrical stimulus which had a strong resemblance to the familiar asymmetrical exemplar, rather than a general preference for symmetry. A further kind of experience, training chickens to respond to some stimuli but not to others, generated a receiver bias for exaggerated stimuli, whereas chickens trained on reversed stimuli developed a bias for less exaggerated stimuli. To investigate the potential of this bias to drive the evolution of signals towards exaggerated forms, a simplified evolutionary process was mimicked. The stimuli variants rejected by the chickens were eliminated, whereas the selected forms were kept and evolved prior to the subsequent display. As a result, signals evolved into exaggerated forms in all tested stimulus dimensions: length, intensity and area, despite the inclusion of a cost to the sender for using increasingly exaggerated signals. The bias was especially strong and persistent for stimuli varying along the intensity dimension where it remained despite extensive training. All the results in my thesis may be predicted by the receiver bias hypothesis. This implies that biases, developed due to stimuli experience, may be significant mechanisms driving the evolution of signal form.

In externally fertilising fishes, various factors in the surrounding environment may influence the viability of the sperm and eggs, thus determining the success of reproduction. In this thesis, the influence of salinity and ovarian fluid on sperm motility has been investigated in three Gasterosteiform fishes. The three-spined stickleback, Gasterosteus aculeatus, has successfully invaded fresh water and differs from most other fishes in its ability to spawn in waters of all salinities. Our results show that sperm of the three-spined is strongly stimulated by the ovarian fluid surrounding the eggs. In fresh water, where the period of motility is only about a minute, ovarian fluid prolongs motility to last several hours. We show that this effect is due to fluid’s ionic content and that the fluid remains in the nest, surrounding the eggs, for a prolonged time due to the proteins and/or other macromolecules in the fluid. Our results explain how successful spawning can occur in fresh water despite that it takes several minutes for all three-spined stickleback eggs to be fertilised. The stimulating effect of ovarian fluid may be one of the factors that have enabled the originally marine three-spined stickleback to colonise fresh water. The fifteen-spined stickleback, Spinachia spinachia, is exclusively marine. We found their sperm motility to be good in seawater, reduced in brackish water, and non-existent in freshwater. The presence of ovarian fluid made no difference in any salinity, a factor that might have contributed to their inability to colonise fresh water. Being regarded as a primitive member of the stickleback family, the lack of response to ovarian fluid suggests that this is not a primitive trait among the sticklebacks. The male straight-nose pipefish, Nerophis ophidion carries the eggs attached to its ventral surface. Fertilisation has previously been suggested to be external, but our results show that their sperm are not motile in seawater alone, but in a mixture of seawater and ovarian fluid. This result, together with the finding of some sperm in the female genital area, and that the sperm head is elongated, suggests that the fertilisation in the straight-nose pipefish occurs in close proximity with the eggs and ovarian fluid. This could then explain why the straight-nose pipefish has minute testes and complete confidence of paternity.

Studies on laboratory animals suggest that developing and newborn mammals are more vulnerable than the adults with respect to the harmful effects of organochlorine (OC) pollutants such polychlorinated biphenyls (PCBs) and OC pesticides (Brouwer et al. 1995; 1998a; Colborn 2004). These effects include neurobiological and neurochemical effects, reproductive effects, reduced brain and circulatory thyroid hormone levels, impaired immune functions and vitamin A homeostasis (Brouwer et al. 1995; Colborn 2004; Safe et al. 1994; Tryphonas 1994). In humans, several of these negative effects of OCs have been reported in children of mothers with high pollutant burdens (Jacobson and Jacobson 1996, 1997; Koopman-Esseboom et al. 1994; Sandau et al. 2002; ten Tusscher et al 2003; Weisglas- Kuperus et al. 2000, 2004). Most organochlorines are highly lipophilic and resistant against degradation, and biomagnify as a function of the trophic level in food webs. Due to long food chains and the lipid richness of marine ecosystems, marine apex predators, such as seals, often accumulate very high burdens of these compounds (Aquilar et al. 2002), exemplifying the particular concern about toxic effects in these species. Studies of newborn phocid seals may be particularly interesting, because seals have lipid rich milk, resulting in the nursed grey seal pups being exposed to relatively high concentrations of OCs (Addison and Brodie 1977, 1987: Addison et al. 1999; Debier et al. 2003; Green et al. 1996; Pomeroy et al. 1996; Schweigert and Stobo 1994) during a period of their life when their endocrine and neural systems are still under development, and under the influence of the potentially disruptive properties of these pollutants (Hall et al. 1998; Simms et al. 2000b). Particularly high concentrations of OCs have been found in seals from the Baltic Sea as compared to seals from the North-Atlantic Ocean (Jenssen 1996; Nyman et al. 2002), and it has been suggested that these high exposure levels severely affects the health of Baltic seals (Bergman 1999; Bergman et al. 2001; Helle et al. 1976a,b; Nyman et al. 2001, 2003; Olsson et al. 1994). Given that the developing mammal might be particularly susceptible to the effects of OCs, it is of special interest to examine possible OC related effects that newborn seals may suffer from. Results from such a study may also predict the effects of OCs on marine mammals in general and possibly on humans (Jenssen 2003). / Paper I and paper IV are reprinted with kind permission of Elsevier, sciencedirect.com

Temporal and spatial variation in the environment can influence the performance of individuals in wild ungulate populations. Of particular importance is an understanding of the mechanisms that shape variation in individual body mass, because several important life history traits are directly related to body mass. Body mass is one of the first traits that is influenced by environmental variation, and often the effect operates through variation in the components of the foraging niche of ungulates. In this thesis, I aim to demonstrate how measurements of environmental variation relate to variation in the foraging niche of ungulates. Furthermore, I aim to explore how variation in ungulate life history traits relates to these variables, and finally, how the management of ungulates could benefit from the incorporation of knowledge about the effects of environmental variation on population dynamics. I use weather observations, large-scale climate indices, and indices of environmental phenology based on satellite-derived vegetation indices (NDVI) to analyse the effect of environmental variation on plants and body mass in moose (Alces alces) and roe deer (Capreolus capreolus) populations. The environmental variables that explained most of the variation in plant performance, measured as radial growth in common juniper (Juniper communis) also explained variation in ungulate body mass. These variables were related to conditions in spring and early summer. Plant growth was low in cold summers, and in spring where the green-up curve as measured by change in photosynthetic activity during spring was moderate. Such growing conditions are recognised to increase the quality of the plants as forage for ungulates. Consequently, moose body mass in autumn showed the opposite pattern than juniper to environmental conditions, indicating that quality of plants, rather than the quantity, is an important component in temperate ungulate foraging niche. Further, regional variation in moose body mass was associated with environmental variables related to forage quality. Roe deer body mass was associated with availability of forage during winter, and not with factors related to summer conditions. Factors related to forage quantity neither influenced temporal nor spatial variation in body mass in the two species. Accordingly, it appears that both weather observations and satellite-derived vegetation indices are able to effectively predict variation in plant performance related to variation in foraging conditions for ungulates. The variation in forage quality in space and time created variation in body mass between populations and between cohorts within a population. Further, the variation in body mass between moose population, caused by variation in the foraging conditions, predicted how the populations differentially respond to the effects of environmental stochastisity. In populations with a high mean body mass, or a low density relative to plant biomass production, available resources buffered environmental stochastisity, and were less influenced by environmental variation than populations with relatively fewer resources available. If wildlife managers fail to incorporate the effects of environmental variation on population performance, e.g. on the recruitment rate, the population may show unexpected and large fluctuations in size. Therefore, managers should attempt to incorporate knowledge of recent environmental conditions on the population when setting harvesting quotas. In face of the large variation in environmental conditions experienced by the ungulate populations in Norway, and the fact that responses to environmental variation varies between populations, management should be regionally adapted, and aim to incorporate variation in vital rates caused by environmental conditions. This is likely to create more stable and predictable populations. In face of the predicted climate and landscape changes in Norwegian forests, environmental variables, e.g. from satellite-derived vegetation indices, have the potential to be a powerful tool for a sustainable management of ungulate populations. Consequently, such information should be incorporated into the management of ungulates in order to a) obtain a management of ungulate populations that is adapted to regional mechanisms of environmental variation, and b) acquire a management that is sustainable in face of future change in climate and landscape that may vary regionally. This calls for a regional differentiation in management strategies.

In the present thesis, levels of polychlorinated biphenyls (PCBs), some chosen organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) were analyzed by gas chromatography in the yolk sac of newly hatched chicks of European shag (Phalacrocorax aristotelis), kittiwake (Rissa tridactyla), Brünnich’s guillemot (Uria lomvia) and common eider (Somateria mollissima) from the Norwegian coast and Svalbard. Levels of vitamin A (retinol), retinyl palmitate and vitamin E (α-tocopherol) were measured in plasma and liver of the hatchlings using high-performance liquid chromatography (HPLC). Using statistics, possible significant relationships between levels of the persistent organic pollutants (POPs) and vitamin levels were examined. Hence, the study aimed to elucidate retinoids and tocopherol as potential biomarkers of POP exposure. An exposure study on domestic duck (Anas platyrhynchos) eggs was also conducted to assess the effects of 2,2’,4,4’,5-pentabromodiphenyl ether (PBDE-99) on vitamin levels under controlled laboratory conditions. There were significant differences in POP levels between the bird species included in the present study. In general, kittiwake hatchlings had higher levels of POPs than the other species, followed by shag, Brünnich’s guillemot and common eider hatchlings. Levels of organochlorine compounds in the hatchlings seemed to be higher than reported in sea bird eggs from the Canadian Arctic but lower than reported in eggs of other seabirds from the Netherlands, the Baltic, the Great Lakes and Japan. In contrast to this, the levels of PBDEs and HBCD seemed to be high in some of the species (kittiwakes, shags) relative to a European scale. Negative relationships were revealed between POPs and morphology in Brünnich’s guillemot hatchlings, indicating that this species may be more responsive with respect to effects of POPs on morphological variables than the other species included in the present study. The importance of considering possible confounding impacts of lipid content when studying effects of POPs on morphological variables was emphasized in shag hatchlings. The study revealed negative correlations between POPs and liver tocopherol levels in domestic duck and shag hatchlings. In Brünnich’s guillemot hatchlings, liver tocopherol levels also were negatively associated with POPs, but the relationships were less strong when the effect of body mass on tocopherol levels was accounted for. In kittiwake and common eider hatchlings, however, there seemed to be a positive influence by POPs on tocopherol levels. Thus, the results should encourage further research on the effects of POPs on tocopherol levels (including oxidized forms of the vitamin). In shag hatchlings, negative relationships between POPs and plasma retinol levels were observed, in line with several previous studies on birds. Since retinol was not influenced in any other species included in the study, tocopherol levels might be more responsive than retinol levels to POP exposure. Additional studies should, however, be conducted before certain conclusions are drawn. Concerning the work needed for further development of vitamins as biomarkers of POP, effort should be done to characterize confounding factors, such as diet and condition of the avian mothers. Although there was no obvious link between the observed responses of vitamins to POP exposure and effects at higher biological levels (i.e. reproduction disturbances, population decline), the relevance of vitamins as potential biomarkers of POP exposure should not be repelled.

Many environmental pollutants, heavy metals and polyaromatic hydrocarbons (PAHs) among them, are toxic by oxidative stress. Oxidative stress may be defined as a state in an organism when its inherent capacity to handle oxyradicals is surpassed, and it may result in peroxidation of lipids, and damage to proteins and DNA. Thus, genotoxic stress may follow oxidative stress. Little is known about the effects of genotoxic stress in invertebrates, although the occurrence of tumors has been known for quite some time, in bivalve mollusks at least since the 1960s. Less dramatic manifestations of genotoxic stress may include impaired enzyme functions, altered protein turnover, with possible effects on physiological processes. Keys to a better understanding of genotoxic stress are the proteins involved in the regulation of the cell-cycle and DNA repair. Virtually nothing is known about these proteins in mussels. The work presented in the papers I, II, and IV aimed to give a first insight into how the blue mussel responds to genotoxic stress following exposure to the polyaromatic hydrocarbon (PAH) benzo[a]pyrene (B[a]P), PAHs in petrochemical pollution, copper (Cu) or cadmium (Cd), all substances known to enhance formation of oxyradicals. PAHs may also be genotoxic by formation of DNA adducts. The cell-cycle and DNA repair proteins studied were the proliferating cell nuclear antigen (PCNA) and the retinoblastoma protein 110 (Rb110). The first is involved in DNA repair and cell proliferation; the second at the G1 checkpoint of the cell-cycle. We showed that the PCNA is a potential marker of genotoxic response (DNA repair, and/or cell proliferation) to PAHs (papers I and IV) and cadmium (paper II). Furthermore, cadmium may possibly elicit a cell-cycle stop mediated by the Rb110 (the paper II). Based on these cell-cycle and DNA repair proteins, the genotoxic responses in blue mussels seem to be similar to that in vertebrates. Markers of general stress or oxidative stress were used in all studies. The applicability of the general stress marker heat shock proteins (HSP70 and HSP60) (papers I and IV), the polyglycoprotein (P-gp) (paper I), a marker of exposure to planar organic compounds, and markers of oxidative stress, such as the antioxidant defense enzyme copper/zinc-superoxide dismutase (Cu/Zn-SOD) (paper II), and the oxidative protein modifications protein carbonyls and disulfides (papers III and IV) were tested in various situations. In accordance with results by others, my studies have shown that HSPs, which formerly were considered as universal stress markers, are not always applicable, as their expression is affected by factors that are difficult to control (papers I). I found that the P-gp can be used as a marker of B[a]P exposure in Baltic Sea blue mussels (paper I). In paper II, I reported that the Cu/Zn-SOD was up-regulated in response to Cd exposure, a clear indication of oxidative stress that was also manifested as a response in the studied cell-cycle and DNA repair proteins. Protein carbonyls were successfully used in the papers III and IV to indicate oxidative stress. In paper III, I also investigated the potential of diagonal gels as a tool for identification of protein disulfides in protein expression signatures (PESs). The diagonal gels hold a good potential for identification of novel and prime targets of oxidative stress. My work was performed as short-term laboratory studies, in vivo, in blue mussels from the Baltic Sea, and as a one year long field experiment with Icelandic blue mussels in a tidal system. The idea was to use blue mussels that were already physiologically challenged (by osmotic stress, or alternating aerobic and anaerobic metabolism), to see how they responded to additional stress in the form of toxicants capable of inducing oxidative and genotoxic stress. Most of the work on biochemical endpoints in blue mussels published so far was done on blue mussels from fully marine environments, and without consideration to the effect of tide.

No description available.