Search
Now showing items 171-180 of 271
Primary production and the relevance of small autotrophic and heterotrophic cells in marine arctic ecosystems
(Doctoral thesis; Doktorgradsavhandling, 2011-12-02)
The Arctic is one of the least studied regions in the world and large changes in marine ecosystem dynamic are expected here because of the increasing air and ocean temperature. The central Arctic Ocean has for a long time been considered as a very low productive ecosystem, but recent estimates of primary production gives relatively high values. The shelves surrounding the Arctic Ocean are highly ...
Decadal changes in distribution, abundance and feeding ecology of baleen whales in Icelandic and adjacent waters. A consequence of climate change?
(Doctoral thesis; Doktorgradsavhandling, 2016-01-15)
Five species of baleen whales are regularly encountered at their feeding grounds in Icelandic waters during summer. Systematic monitoring of distribution and abundance of cetaceans in Icelandic and adjacent waters was initiated in 1987 as a part of the North Atlantic Sightings Surveys (NASS). In this thesis, the objecive is to summarize the results of these surveys in relation to changes in the ...
Calanus glacialis : the role of lipids in the life cycle and for the Arctic pelagic food web
(Doctoral thesis; Doktorgradsavhandling, 2012-05-23)
The Arctic marine ecosystem is characterized by strong seasonality and a short but productive period of primary production in the spring when the ice breaks up. Calanus glacialis is one of the key links between primary producers and higher trophic levels, and it is adapted to the strong seasonality by life cycle traits such as; seasonal vertical migration, diapausing, reproduction in the spring and ...
Acute and long-term effects from petroleum discharges on temperate and Arctic Calanus species
(Doctoral thesis; Doktorgradsavhandling, 2011-11-11)
Summary
Petroleum exploitation is emerging in the Arctic. In the Norwegian Arctic the southern Barents Sea is opened for development of oil and gas fields. This same area holds some of the world's largest and well managed commercial fish stocks such as Herring (Clupea harengus), Capelin (Mallotus villosus), Haddock (Melanogrammus aeglefinus), Atlantic Cod (Gadus morhua). For the interest of the ...
Live-storage of wild mature cod (Gadus morhua L.) without feed supply. Effects on biological and quality properties
(Doctoral thesis; Doktorgradsavhandling, 2018-09-28)
The overall aim of this work was to obtain better understanding of how live-storage without feeding affects wild mature Atlantic cod (Gadus morhua L.) and quality of products obtained from such cod. Atlantic cod were live-stored without feeding for 82 days. First, gender-specific weight changes in both whole and gutted fish, as well as certain organs were studied (Paper I). Next, the effects of feed ...
Catch quality and size selectivity in the Barents Sea bottom trawl fishery: effect of codend design and trawling practice
(Doctoral thesis; Doktorgradsavhandling, 2019-02-15)
This study focused on two important issues on the Barents Sea bottom trawl fishery for Northeast Arctic cod (Gadus morhua L.); catch quality (i.e., the quality of the fish caught) and size selectivity. The high abundance of cod encountered in recent years in the Barents Sea, leading to subsequent large annual quotas, has led to increased interest in improving the quality of fish caught by trawls. ...
Bivalves as indicators of environmental perturbations related to climate and ocean acidification
(Doctoral thesis; Doktorgradsavhandling, 2015-03-13)
The aims of this thesis were to increase knowledge on 1) susceptibility of bivalves to environmental perturbations and 2) usage of bivalve shells as sub-annual environmental proxy archives. These objectives were addressed using two experimental settings: 1) an ocean acidification (OA) experiment on bivalve gametes and early larval stages, and 2) year-long bivalve deployments on oceanographic moorings ...
Francisella noatunensis ssp. noatunensis in Atlantic cod - Intracellular localization, innate immune responses and antibacterial proteins
(Doctoral thesis; Doktorgradsavhandling, 2016-11-24)
SUMMARY
Francisellosis has in the cod farming industry caused big economic losses because of no available vaccine or treatments. Understanding host-pathogen mechanisms is especially important when traditional vaccine strategies using inactivated bacteria are not functional.
The focus of this thesis has been to study interactions between the host and the pathogen causing the disease. The bacterium ...
Adjuvant combinations with the Toll-like receptor ligand CpG - Protective immune responses in Atlantic salmon
(Doctoral thesis; Doktorgradsavhandling, 2016-12-01)
Aquaculture is in need of improved viral vaccines to meet the demands of a growing sustainable industry. Fish viral vaccines are often based on less immunogenic antigen (Ag) formulations that require adjuvants to elicit sufficient protection. Toll-like receptor (TLR) agonists holds high immunostimulatory properties and are in mammals well explored vaccine adjuvants. The potential of synthetic ...
Antimicrobial peptides in Urticina eques and Echinus esculentus. Isolation, characterisation, and structure-activity relationship studies
(Doctoral thesis; Doktorgradsavhandling, 2016-12-09)
Bacterial resistance to antibiotics has become a serious global problem. Infections that once were easily cured with antibiotics have now become nearly impossible to treat. Thus, there is a desperate need for new antibacterial drugs. Antimicrobial peptides (AMPs) are a diverse group of compounds. Amongst their unique features are their ability to kill bacteria (often both Gram-positive and Gram-negative) ...