The pelagic zone is the largest ecosystem on Earth. The inhabitants of this ecosystem are not provided with any substances to hide behind. Diel vertical migration (DVM) is believed to be a trade-off between substantial ...

Karpefisken karuss (Carassius carassius) har en unik evne til å tolerere svært lave oksygennivåer, og kan leve i helt anoksiske tilstander over flere måneder under isdekke. Dens unike egenskaper innebærer en svært høy ...

Pelagic copepods are hosts to numerous protistan parasites, which can have devastating effects on host fitness. Effects of parasitism include increased mortality, behavioral modifications, sterility and death. Although ...

I løpet av de siste ti årene har det vært rapportert en omfattende nedgang av blåskjell i Oslofjorden. Dette har blitt meldt fra både kystbefolkning og hytteeiere, men også fra forskere. Nedgangen i blåskjell er en trend ...

Cod (Gadus morhua ) and capelin (Mallotus villosus) play an important ecological and commercial role in the Barents Sea. Capelin provide high lipid energy to many of its predators in the Barents Sea including cod, which ...

Økt menneskelig påvirkning på kystområder kan føre til at endringer i fysiske og biologiske miljøfaktorer skjer raskt. Slike endringer vil være utfordrende for en rekke arter tilpasset spesifikke økosystem. Marine ...

The presence of microplastics in the marine environment is an emerging concern for marine life. This study investigated the presence of low-density polyethylene (LDPE) particles (20-25 μm) in the gills, intestinal lumen, ...

Plastic pollution has become a major threat to many marine ecosystems, and there is a need for an improved understanding of its impact on marine organisms. Studies have mainly focused on lower trophic levels, including ...

Environmental changes are affecting a great number of marine ecosystems. Many top predators are particularly vulnerable to such changes as they are contingent on the various prey species along the food chain and their ...

Growth of two red algae species (Palmaria palmata and Vertebrata lanosa) in lab culture Newt Petride Master of Science Thesis Department of Biosciences Section for Aquatic Biology and Toxicology (AQUA) University of Oslo ...

Bentiske makroalger kan fortelle oss om hvordan miljøforholdene i et område har vært over en lengre periode. De er fastvoksende, og kan ikke flykte fra faktorer som økende sjøtemperatur, næringsberikelse av vannmasser eller ...

Bentiske alger og ålegras utgjør to viktige marine habitater langs Norges kystlinje. Bentiske diatomeer som epifytter er ofte funnet på disse. Det er ingen tidligere studier fra tempererte områder av sesongmessig variasjon ...

During the 1980`s it was discovered that fishes from the wrasse family (Labridae) along the Norwegian coast could be utilized as cleaner fish for controlling sea-lice infestations in commercial fish farming. Since this ...

Microplastics contaminate marine environments worldwide, but there is little knowledge of whether and how benthic foraminifera are affected. The aim of this project was to clarify whether microplastics accumulate in and ...

The retreat of glaciers, melting of permafrost, and increased riverine runoff influence Arctic fjords and their physical and biological environment, but to which extent is poorly known. In this study, I determined the ...

The use of remote video traps is a popular method of studying animal behavior in nature. It is an efficient, inexpensive and non-invasive way of obtaining samples from the field. In this study, I built and used video traps ...

Brown trout (BT) and Arctic char (AC) are freshwater species exhibiting a wide array of life history and migration strategies. Populations with free access to the marine environment often display anadromous tendencies, ...

Laminaria hyperborea is an important species of kelp comprising large kelp forests along the Norwegian coast. Large quantities of detritus from these forests are exported to other ecosystems. These exports could support ...

Denne undersøkelsen har registret forekomst av makroalger og dyr på 7 utvalgte stasjoner i Ytre Hvaler nasjonalparks fjæresone, inkludert fjærepytter. Feltarbeidet ble utført over to sesonger: I april (vår) og august (høst) ...

Ytre Hvaler nasjonalpark ble opprettet i 2009 for å bevare urørt natur i et marint miljø. Samtidig er nasjonalparken et viktig rekreasjonsområde for mange mennesker, og fjæresonen kan lett påvirkes av menneskelig aktivitet ...

At the prospect of global warming, an understanding of how increasing temperatures may affect both species and communities becomes increasingly important. In 2002, a regime shift occurred along the Norwegian Skagerrak coast ...

The responses in size, survival and other life-history traits in the cladoceran Daphnia magna were assessed at two temperatures (15 and 25ºC) across a calcium (Ca) gradient (0.5, 4 and 106 mg Ca/l) for two different clones ...

The sea urchin, Strongylocentrotus droebachiensis, is a prominent grazer in coastal ecosystems with the ability to graze down large areas of kelp forests and turn them into marine deserts, or so called barren grounds. Kelp ...

European lobsters (Homarus gammarus) have been overfished for decades as it is a highly valued species. Commercial catch per unit of effort (CPUE) in Skagerrak, Norway has decreased to historically low levels in the most ...

In Antarctica, the failure to establish international agreement on regulations caused an overexploitation which reduced the number of blue whales from about 240 000 to less than 500. I have here taken a closer look at the ...

Data from a monitored segment (about 20 vessels) of the fleet of about 6000 small vessels (less than 15 meters length overall) operating bottom-set gillnets for cod (Gadus morhua) and monkfish (Lophius piscatorius) in the ...

Sammendrag Kokkolitoforer, også kalt kalkflagellater, er en viktig gruppe marine planktonalger. Det som kjennetegner denne algegruppen er at de produserer skjell , kalt kokkolitter, på utsiden av cellen som er dannet av ...

It is important both from a management and conservation point of view to uncover the potential of a species to cope with climate warming, and whether this potential differ among populations. In this thesis I used Atlantic ...

Protists have representatives in all but one of the kingdoms in the tree of life and are highly important in the oceans, where they generate most of the carbon-flow in the first trophic levels. Parasitic lineages work as ...

The tropical Red Sea coast of Saudi Arabia is dominated by intertidal soft sediments, seagrass meadows and mangrove beaches. These habitats have been under high pressure for decades partly due to anthropogenic activity. ...

Temperature and elemental composition are key factors that affect life history traits in algae. Climate change is predicted to cause major temperature changes in the ocean that may affect algal populations, seasonal dynamic ...

My experiments tried to investigate the effect of available surfaces on rotifer growth, and the benefits of the attached state. A linear model was formulated to test whether the predictions for functional respones of ...

A description of the epidermal structure of minke and humpback whales in relation to their respective capabilities of retaining suction-cup tags.

Predator-prey interactions are prevalent in all natural ecosystems and are regarded as a fundamental force in ecological as well as in evolutionary processes. A series of studies have investigated predator-prey dynamics ...

Protists are a highly abundant and diverse group of microorganisms that hold important ecological roles in all aquatic ecosystems. Phototrophic protists are responsible for a large portion of the global primary production, ...

In this thesis a bio-optical model was used in order to identify and characterise diversity and fertilisation effects on primary productivity in Freshwaters. The experiments were conducted in mesocosms, comprising 12 ...

Prymnesium polylepis er en svepeflagellat med to ulike morfologiske flagellatstadier som består av avvikende eller typiske celler. Kulturer med typiske celler er haploide, og kulturer med avvikende celler kan enten være ...

A first survey of southern Norway to sample and examine Norwegian Kinorhyncha biodiversity. Also beginning to establish a sequence database for future use in Kinorhyncha barcoding.

The Dinoflagellates are an intriguing and diverse protist group in terms of morphology, ecology and geographical distribution amongst others. The proportion of heterotrophic and photosynthetic taxa are rougly even. However, ...

Abstract Six flatfish species were collected by trawling at five locations in the inner and middle Oslofjord between February and December in 2013. In total 386 individuals were sampled. The purpose of this investigation ...

Blåkvalen (Balaenoptera musculus) er det største dyret som har levd på jorda, men i løpet av den fyrste halvdelen av det 20 hundreåret vart han nesten utrydda på grunn av jakt. Loggbøkene brukt i denne undersøkinga høyrer ...

In studies on reproductive ecology of pelagic copepods, the role of males is often neglected and male reproductive investment is not well understood. Lately there has been an increasing interest in the topic and it has ...

This thesis examines the phytoplankton diversity in the Oslo Fjord and the seasonality of the size, shape and abundance of the genus Dinophysis Ehrenberg. The genus, which contains several toxin-producing species, has ...

Introduction: Lake productivity is determined by the amount of nutrients and light available. While phosphorus is the main limiting nutrient in freshwater systems light availability can be reduced by several factors, while ...

The differences in early life history traits among populations of grayling in Lake Lesjaskogvatn and surrounding lakes have been extensively studied the last decades. These populations are the offspring of a small group ...

Copepods are said to be the key link between the primary producers and higher trophic levels. They inhabit all oceans and are found in almost all marine communities. In the ocean, it is common to observe skewed sex-ratios ...

Practically every Atlantic cod (Gadus morhua) stock have suffered from depletion and overfishing, placing the fish on IUCN’s Red List as ‘Vulnerable’. The Skagerrak Coastal Cod stocks are in no better shape, reported to ...

Intense salmon farming regimes in Norway have resulted in hundreds of thousands of salmon escaping each year. These domesticated salmon have been selectively bred for generations and therefore have the potential to genetically ...