<p>A low content of organic matter, which is largely refractory in nature, is characteristic of most sediments, meaning that aquatic deposit-feeders live on a very poor food source. The food is derived mainly from sedimenting phytodetritus, and in temperate waters like the Baltic Sea, from seasonal phytoplankton blooms. Deposit-feeders are either bulk-feeders, or selective feeders, which preferentially ingest the more organic-rich particles in the sediment, including phytodetritus, microbes and meiofauna.</p><p>The soft-bottom benthos of the Baltic Sea has low species biodiversity and is dominated by a few macrobenthic species, among which the most numerous are the two deposit-feeding amphipods <i>Monoporeia affinis</i> and<i> Pontoporeia femorata</i>, and the bivalve <i>Macoma balthica</i>. This thesis is based on laboratory experiments on the feeding of these three species, and on the priapulid <i>Halicryptus spinulosus.</i> </p><p>Feeding by benthic animals is often difficult to observe, but can be effectively studied by the use of tracers. Here we used the radioactive isotope ¹⁴C to label food items and to trace the organic matter uptake in the animals, while the stable isotopes ¹³C and¹⁵N were used to follow feeding on aged organic matter in the sediment. </p><p>The abundance of<i> M. balthica</i> and the amphipods tends to be negatively correlated, i.e., fewer bivalves are found at sites with dense populations of amphipods, with the known explanation that newly settled <i>M. balthica</i> spat are killed by the amphipods. Whether the postlarvae are just accidentally killed, or also ingested after being killed was tested by labelling the postlarvae with ¹⁴C and Rhodamine B. Both tracer techniques gave similar evidence for predation on and ingestion of postlarval bivalves. We calculated that this predation was likely to supply less than one percent of the daily carbon requirement for <i>M. affinis</i>, but might nevertheless be an important factor limiting recruitment of <i>M. balthica. </i></p><p>The two amphipods <i>M. affinis</i> and <i>P. femorata </i>are partly vertically segregated in the sediment, but whether they also feed at different depths was unknown. By adding fresh 14C-labelled algae either on the sediment surface or mixed into the sediment, we were able to distinguish surface from subsurface feeding. We found <i>M. affinis</i> and <i>P. femorata</i> to be surface and subsurface deposit-feeders, respectively. </p><p>Whether the amphipods also feed on old organic matter, was studied by adding fresh ¹⁴C-labelled algae on the sediment surface, and using aged, one-year-old ¹³C- and ¹⁵N-labelled sediment as deep sediment. Ingestion of old organic matter, traced by the stable isotopes, differed between the two species, with a higher uptake for <i>P. femorata</i>, suggesting that <i>P. femorata</i> utilises the older, deeper-buried organic matter to a greater extent.</p><p>Feeding studies with juveniles of both <i>M. affinis</i> and <i>P. femorata</i> had not been done previously. In an experiment with the same procedure and treatments as for the adults, juveniles of both amphipod species were found to have similar feeding strategies. They fed on both fresh and old sediment, with no partitioning of food resources, making them likely to be competitors for the same food resource. </p><p>Oxygen deficiency has become more wide-spread in the Baltic Sea proper in the last half-century, and upwards of 70 000km² are now devoid of macrofauna, even though part of that area does not have oxygen concentrations low enough to directly kill the macrofauna. We made week-long experiments on the rate of feeding on ¹⁴C-labelled diatoms spread on the sediment surface in different oxygen concentrations for both the amphipod species, <i>M. balthica</i> and <i>H. spinulosus. </i>The amphipods were the most sensitive to oxygen deficiency and showed reduced feeding and lower survival at low oxygen concentrations.<i> M. balthica</i> showed reduced feeding at the lowest oxygen concentration, but no mortality increase. The survival of <i>H. spinulosus</i> was unaffected, but it did not feed, showing that it is not a surface deposit-feeder. We conclude that low oxygen concentrations that are not directly lethal, but reduce food intake, may lead to starvation and death in the longer term.</p>

<p>Natural stress and disturbances are important factors affecting the structure and function of ecosystems. However the magnitude of stress has escalated due to anthropogenic activities. Environmental monitoring and toxicity assessments try to protect ecosystems from unwanted human alterations. The aim of this Doctoral thesis was to increase the understanding of the complex effects that environmental stress has on individuals and invertebrate populations. The low saline environment in the Baltic Sea is perceived as stressful for most organisms living there. In Paper I, it was found that Baltic blue mussels living in the less saline northern Baltic Proper (~5 psu) had lower basal metabolism and were more susceptible to toxic exposure than the mussels in the south (~7 psu). There was no genetic differentiation between the mussels from the northern and southern areas while there were genetic differences between mussels from sites within the respective areas (Paper III), indicating that there is not a simple relationship between the health of the mussels and genetic diversity in the microsatellite loci studied. In Paper IV it was found that the heat tolerance of the intertidal dogwhelk <i>Nucella lapillus</i> is oxygen dependent. Increased oxygen levels resulted in higher survival rate. Protein expression profiles also became more similar to those of the controls, compared to the whelks exposed to high temperature and normal oxygen levels. In Paper V and VI it was found that exposure to a single toxicant for more than one generation decreased the genetic diversity in exposed copepod populations even though abundances remained unaltered. In Paper VI, exposure to naturally contaminated sediments, which contained of a mixture of toxicants, did not decrease genetic diversity. However the genetic divergence (<i>F</i><i>ST</i>) within the treatments was very high, probably due to small effective population sizes in the replicates. Likewise in Paper III, the very low blue mussel abundance in the north together with the stressful environment suggests a small effective population in the northern Baltic Proper. In conclusion, my studies show that, measuring effects on several levels, including both functional and structural endpoints will both increase the sensitivity of the tests and increase their ecological relevance. </p>

<p>In this thesis we have studied speciation in three butterfly genera <i>Polygonia</i> (Nymphalidae, Nymphalini), <i>Pararge </i>(Nymphalidae, Satyrinae) and <i>Celastrina</i> (Lycaenidae: Polyommatinae). In the first paper a dated phylogeny, based on molecular data, of <i>Polygonia</i> was constructed. We found strong conflict between the nDNA and mtDNA datasets. Possibly this can be explained by ancestral and recent hybridizations between contemporary taxa. The results point to the importance in using different markers when we try to resolve evolution of taxa. In the second paper a sister group comparison was made in order to discover whether host plant range has had an effect on species diversity in <i>Polygonia</i>. Our result indicated higher diversification rates in clades which included species with larvae feeding on different, or additional, plants compared to the ”urticalean rosids” specialists. In the third paper our focus was on the colonization abilities in polyphagous butterflies. The haplotype structures of the mtDNA <i>cytochromeoxidase I</i> (COI) within the Nearctic species of <i>Celastrina</i> as well as within<i> P. c-album</i> and <i>P. faunus</i> were analysed in a network. We found little variation in <i>Celastrina</i> and <i>P. c-album.</i> This results imply that the genera have expanded recently and rapidly. There are indications of differentiation in COI in <i>Celastrina</i> and, possibly, host plant use is involved. However, in <i>P.</i> <i>faunus</i> we found structure among the haplotypes. We believe that several different haplotypes of this species have been preserved during glaciations in the Nearctic. In the fourth paper the evolution of the grassfeeding <i>Pararge</i> was analysed. The phylogeny was based on the mtDNA COI and the nDNA <i>wingless</i> (wgl) and times of divergences were calculated. We found a deep divergence between the European and Moroccan populations of <i>P. aegeria</i> which indicates the importance of the Mediterranean as a barrier for gene flow. </p>

<p>A solid-phase extraction (SPE) method was developed for the determination of organochlorine pesticides, namely aldrin, alpha-BHC, beta-BHC, delta-BHC, dieldrin, endosulfan I, endosulfan II, endosulfan sulfate, endrin, endrin aldehyde, lindane, heptachlor, heptachlor epoxide, 4,4’-DDD, 4,4’-DDE and 4,4’- DDT in water. The effect of extraction conditions, such as the addition of sodium chloride and methanol to the sample prior to loading was studied. The sample was concentrated by a plain polystyrene-divinylbenzene resin, and the extract was eluted by ethyl acetate. Qualification and quantification of the target pesticides were performedby gas chromatography/ mass spectrometry (GC/MS) in the full-scan and selected ion-monitoring mode, respectively, and for better detection of pesticides in field samples the mass spectrometer was altered from electron ionization (EI) to chemical ionization mode (CI). The repeatability of the method for MilliQ-water fortified with pesticides at a level of 0.1 to 0.6 µg/l ranged from 8 to 18%, and the obtained recoveries ranged from 67 to 135%. </p><p>The method was evaluated for the determination of organochlorine pesticides in fourteen surface- and groundwater samples taken from locations along King Talal Dam, King Abdullah Canal and Zarqa River in the Jordan Valley. The limit of detection of the pesticides residues in 500-ml field water samples ranged from 0.0009 to 15.7 ng/l. The obtained results confirmed the presence of trace amounts of some organochlorine pesticides in the analyzed samples, i.e. lindane and endosulfan compounds.</p>

<p>Våtmarker som anläggs på jordbruksmark kan förhindra att fosfor från åkrarna når sjöar och vattendrag och hjälper därmed till att minska övergödningen. Det är viktigt att utforma våt-marken på ett sådant sätt att så mycket som möjligt av den biotillgängliga fosforn hålls kvar. Syftet med studien var att undersöka om det finns ett positivt samband mellan lerinnehåll och fosfors biotillgänglighet i en anlagd våtmarks sediment. Syftet var även att undersöka om partikelstorleken minskar gradvis med avståndet från inloppet, det vill säga om mer lera sedimenterar närmare utloppet. Prover togs längs tre transekter från sedimentet i en våtmark i västra Östergötland och fosfor- samt partikelstorleksanalyser gjordes. Genom extraktion med ammoniumklorid (NH4Cl) kunde lättillgänglig fosfor bestämmas. Partikelstorleksanalysen gjordes med en modifierad pipettmetod, baserad på att större partiklar sedimenterar fortare än mindre partiklar. Regressionsanalys visade att partikelstorleken minskade signifikant från inlopp till utlopp i våtmarken. Däremot hittades inte några signifikanta samband mellan partikelstorlek och lättillgänglig fosfor eller totalfosfor, i motsats till resultat i andra studier. Halterna av både lera och olika fosforfraktioner i sedimentet var relativt låga och likartade vid olika provpunkter i våtmarken vilket kan ha påverkat resultaten.</p>

<ul><li>Energiflöden mellan terrestra och akvatiska ekosystem har uppmärksammats mycket den senaste tiden. I den här studien undersöker jag betydelsen av ett terrestert djur, älgen (<em>Alces alces</em>), som dör i vattendrag och avger näring till vattnet. Genom litteraturstudier och teoretiska beräkningar uppskattade jag hur vanligt det är att älgar dör i vattendrag och om dessa älgar har någon inverkan på vattendragets totala näringsbudget. Jag fann att drunkning hos älgar tas upp som en parameter för naturliga dödsorsaker i flera artiklar från USA, Canada och Polen. Orsakerna till att älgar drunknar, trots att de är duktiga simmare, kan vara t.ex. att stranden är för brant, att de tvingas ner i vattnet av rovdjur, att skadeskjutna älgar söker sig till vatten på grund av törstkänningar i samband med blodförlust eller att de går igenom svaga isar. Utifrån teoretiska beräkningar fann jag även att en älg som dött i ett vattendrag bidrar till mycket liten del av den totala näringsbudgeten. Min hypotes är att det endast blir en lokal påverkan nedströms djuret. Hur denna påverkan ser ut och om den kommer primärproducenter och fiskar tillgodo är mycket komplext och undersöks inte i denna studie.</li></ul>

<p>The climate change is expected to affect especially alpine areas negatively, replacing the alpine flora with subalpine forest. The understanding of how vegetation influences total organic carbon (TOC) in soil, streams and lakes in alpine and subalpine areas will lead to a better understanding of the effects of climate change, and will also increase the knowledge of the ecotone as a whole. In this study plant-soil relations were examined in a subalpine and an alpine catchment in the north of Sweden, by comparing dissolved organic carbon (DOC) concentrations, 13C-DOC, 13 compared with lake and stream water DOC, as well as sediment OC from the recipient lakes in the catchments.</p><p> The results show that subalpine forests at lower altitudes, have higher DOC concentrations, higher C:N ratios, and more depleted Particulate OM in water and inlets, show that allochthonous carbon influences water properties in both catchments, as does primary production by benthic and pelagic algae, separating shallow and deep sediment Differences between the catchments are explained with the higher primary production of organic material and root exudations from trees in the subalpine forested catchment effecting the whole catchment dynamics. C-SOM and the carbon to nitrogen (C:N) ratios. The terrestrial bulk chemical properties of DOC were alsoδ13C signals in soil, and soil-solution compared to alpine areas. δ13C signals from Dissolved OM andδ13C signals.</p>

<p>Virtually all diurnal birds have tetrachomatic vision based on four different colour receptors. As a result, birds are potentially able to perceive their environment in twice as many colours as humans and four times as many colours compared to most other mammals, which are dichromatic. In addition to the spectrum visible to humans, birds are able to detect ultraviolet (UV) light. Signals with a UV component have been shown to be important to birds both in foraging and colour signalling. Because of the superior colour discrimination of the avian eye, UV sensitivity, but especially owing to its tetrachromacy, we cannot know what birds look like to those that matter, i.e. other birds.</p><p>In my thesis I describe a new molecular method with which it is possible to identify the vision system of birds only using a small amount of DNA, without the need to keep or sacrifice the animal. It thereby facilitates large screenings, including rare and endangered species. The method has been used to increase the number of species with identified vision system type from 19 to 66. I show that raptors and songbirds have different vision systems, giving songbirds the possibility of a secret channel for colour signalling, and that male songbirds in coniferous forest take advantage of this to be significantly more cryptic to raptors than to females songbirds. I show that gulls have gained a vision system enabling them to detect the UV signals of fish when the fish swim close to the surface.</p><p>Even though we tend to be rather self-satisfied with the quality of our colour vision, we are colour-blind when compared to birds. My work shows that human colour vision is inadequate for judging animal coloration, and that there is much more going on in bird colour signalling than meets our eye.</p>

Virtually all diurnal birds have tetrachomatic vision based on four different colour receptors. As a result, birds are potentially able to perceive their environment in twice as many colours as humans and four times as many colours compared to most other mammals, which are dichromatic. In addition to the spectrum visible to humans, birds are able to detect ultraviolet (UV) light. Signals with a UV component have been shown to be important to birds both in foraging and colour signalling. Because of the superior colour discrimination of the avian eye, UV sensitivity, but especially owing to its tetrachromacy, we cannot know what birds look like to those that matter, i.e. other birds. In my thesis I describe a new molecular method with which it is possible to identify the vision system of birds only using a small amount of DNA, without the need to keep or sacrifice the animal. It thereby facilitates large screenings, including rare and endangered species. The method has been used to increase the number of species with identified vision system type from 19 to 66. I show that raptors and songbirds have different vision systems, giving songbirds the possibility of a secret channel for colour signalling, and that male songbirds in coniferous forest take advantage of this to be significantly more cryptic to raptors than to females songbirds. I show that gulls have gained a vision system enabling them to detect the UV signals of fish when the fish swim close to the surface. Even though we tend to be rather self-satisfied with the quality of our colour vision, we are colour-blind when compared to birds. My work shows that human colour vision is inadequate for judging animal coloration, and that there is much more going on in bird colour signalling than meets our eye.

A low content of organic matter, which is largely refractory in nature, is characteristic of most sediments, meaning that aquatic deposit-feeders live on a very poor food source. The food is derived mainly from sedimenting phytodetritus, and in temperate waters like the Baltic Sea, from seasonal phytoplankton blooms. Deposit-feeders are either bulk-feeders, or selective feeders, which preferentially ingest the more organic-rich particles in the sediment, including phytodetritus, microbes and meiofauna. The soft-bottom benthos of the Baltic Sea has low species biodiversity and is dominated by a few macrobenthic species, among which the most numerous are the two deposit-feeding amphipods Monoporeia affinis and Pontoporeia femorata, and the bivalve Macoma balthica. This thesis is based on laboratory experiments on the feeding of these three species, and on the priapulid Halicryptus spinulosus. Feeding by benthic animals is often difficult to observe, but can be effectively studied by the use of tracers. Here we used the radioactive isotope 14C to label food items and to trace the organic matter uptake in the animals, while the stable isotopes 13C and 15N were used to follow feeding on aged organic matter in the sediment. The abundance of M. balthica and the amphipods tends to be negatively correlated, i.e., fewer bivalves are found at sites with dense populations of amphipods, with the known explanation that newly settled M. balthica spat are killed by the amphipods. Whether the postlarvae are just accidentally killed, or also ingested after being killed was tested by labelling the postlarvae with 14C and Rhodamine B. Both tracer techniques gave similar evidence for predation on and ingestion of postlarval bivalves. We calculated that this predation was likely to supply less than one percent of the daily carbon requirement for M. affinis, but might nevertheless be an important factor limiting recruitment of M. balthica. The two amphipods M. affinis and P. femorata are partly vertically segregated in the sediment, but whether they also feed at different depths was unknown. By adding fresh 14C-labelled algae either on the sediment surface or mixed into the sediment, we were able to distinguish surface from subsurface feeding. We found M. affinis and P. femorata to be surface and subsurface deposit-feeders, respectively. Whether the amphipods also feed on old organic matter, was studied by adding fresh 14C-labelled algae on the sediment surface, and using aged, one-year-old 13C- and 15N-labelled sediment as deep sediment. Ingestion of old organic matter, traced by the stable isotopes, differed between the two species, with a higher uptake for P. femorata, suggesting that P. femorata utilises the older, deeper-buried organic matter to a greater extent. Feeding studies with juveniles of both M. affinis and P. femorata had not been done previously. In an experiment with the same procedure and treatments as for the adults, juveniles of both amphipod species were found to have similar feeding strategies. They fed on both fresh and old sediment, with no partitioning of food resources, making them likely to be competitors for the same food resource. Oxygen deficiency has become more wide-spread in the Baltic Sea proper in the last half-century, and upwards of 70 000km2 are now devoid of macrofauna, even though part of that area does not have oxygen concentrations low enough to directly kill the macrofauna. We made week-long experiments on the rate of feeding on 14C-labelled diatoms spread on the sediment surface in different oxygen concentrations for both the amphipod species, M. balthica and H. spinulosus. The amphipods were the most sensitive to oxygen deficiency and showed reduced feeding and lower survival at low oxygen concentrations. M. balthica showed reduced feeding at the lowest oxygen concentration, but no mortality increase. The survival of H. spinulosus was unaffected, but it did not feed, showing that it is not a surface deposit-feeder. We conclude that low oxygen concentrations that are not directly lethal, but reduce food intake, may lead to starvation and death in the longer term.