Doktorgradsavhandlinger (BFE-fak)

Studies on the amphipod genus Metopa (Stenothoidae) : Taxonomy, Ecology, Phylogeny

Tandberg, Anne Helene S. — Sun, 18 Dec 2011 23:00:00 GMT

Tandberg, Anne Helene S.
The Amphipod-genus Metopa is a relatively large genus, with currently 55 accepted species. This PhD thesis consists of redescriptions of 23 of these species based on typespecimens or specimens collected and identified by the original authors; this has been done to create consistent descriptions that could form a basis for a phylogenetic analysis of Metopa. For some species Scanning Electron Microscopy has been used to look for characters that have been overlooked by the original authors. The redescriptions are presented in 3 papers (Papers 1-3), with a phylogenetic analysis of 37 Metopa species (mostly based on personal examinations, but 6 based on literature-information) together with 6 Stenula species (partly based on literature, but most from examinations performed by Dr. Traudl Krapp-Schickel) presented in a manuscript (Paper 6). The result of the phylogenetic analysis is two clear clades (A and B), both including species from both original genera. This result could suggest a thorough change in stenothoid systematics, with the possible synonymization of Stenula into the older Metopa and erection of one or more new genera to include the species of clade A, but we have argued against doing this before further investigations have been undertaken. The stability of the resulting phylogeny is discussed, and in our opinion further studies are necessary to strengthen the conclusions reached here, before we formally make the necessarily very extensive nomenclatorial changes. However, the indications that Metopa and Stenula are paraphyletic are strong. Two papers (Papers 4-5) examine the ecology of Metopa species associated with mollusks. Paper 4 is a short note about findings of Metopa alderii inside the mussel Musculus spp., whereas Paper 5 is a more thorough discussion on the possible life history strategies for Metopa glacialis in its well known association with the mussel Musculus discors based on data collected by Svalbard. We show the presence of more than one broods in several examined mussels, and from the brood sizes and cohort compositions we suggest two possible scenarios: 3 or more seasons of single broods and parental care over more than 1 year after hatching, or multiple broods in one season and extended parental care. The introductory synthesis to the papers gives a short discussion of the papers, in addition to a historical introduction to both taxonomy and the amphipod-genus Metopa. A complete list of taxa that at some time have been included in Metopa is presented, this includes synonymies and references to the auctors and different authors who have moved the different taxa. There is also a table with biogeographical information about the genus, and the ecology of Metopa is discussed. A short discussion on molecular methods and the possible ways to ensure more data for a better phylogenetic analysis is also included.
The papers of this thesis are not available in Munin.
1. Tandberg, A.H.S. and Vader, W.: 'A redescription of Metopa species (Amphipoda, Stenothoidae) based on the type material. 1. Zoological Museum, Copenhagen (ZMUC)', Zootaxa (2009) 2093:1-36. Available at http://www.mapress.com/zootaxa/
2. Tandberg, A.H.S.: 'A redescription of Metopa species (Amphipoda, Stenothoidae) based on the type material. 2. The United States National Museum of Natural History (NMNH)', Zootaxa (2009) 2309:43-68. Available at http://www.mapress.com/zootaxa/
3. Tandberg, A.H.S.: 'A redescription of Metopa species (Amphipoda, Stenothoidae) based on the type material. 2. The Natural History Museum Oslo (NHM)', Zootaxa (2010) 2465:1-94. Available at http://www.mapress.com/zootaxa/
4. Tandberg, A.H.S., Schander, C. and Pleijel, F.: 'First record of the association between the amphipod Metopa alderii and the bivalve Musculus', Marine Biodiversity Records (2010) 3, e5. Available at http://dx.doi.org/10.1017/S1755267209991102
5. Tandberg, A.H.S., Vader, W. and Berge, J.: 'Metopa glacialis : an analysis of its ecology and its association with Musculus discors', Polar Biology (2010) 33:1407-1418. Available at http://dx.doi.org/10.1007/s00300-010-0833-9
6. Tandberg, A.H.S. and Vader, W.: 'Phylogenetic analysis of the stenothoid genera Metopa and Stenula (Crustacea, Amphipoda, Stenothoidae)' (manuscript)

Bacterial flagellin : a novel adjuvant for vaccine strategies

Hynes, Natasha — Mon, 17 Oct 2011 22:00:00 GMT

Hynes, Natasha
Flagellin is the principal structural protein in the locomotive organ flagellum present on flagellated bacteria, and is known to be an important evolutionarily conserved PAMP. Flagellin has been shown to bind to the PRR TLR5 which induces innate immune system responses and signaling pathways. In mammals, much focus has been placed on this protein in vaccine studies for its possible function as an adjuvant. Flagellin (FlaD from Vibrio anguillarum) was recombinantly produced in two forms, full-length (FDL) and a truncated form (FDS) with portions of the N- and C-termini removed to prevent polymerization. Both forms of flagellin were tested alone and in combination with an antigen in a dose response study to determine the most effective dosage to produce a strong immune response. A polyclonal antibody for FDS was produced and showed good specificity in immunoblot testing. Cell culture was used to compare the NF-κB response after stimulation with FDL versus FDS and resulted in a significantly larger response in cells stimulated with FDL. QPCR mRNA gene expression results showed a strong innate immune response with a number of genes known to be induced downstream by the TLR signaling pathway up- regulated including important TLR5S and inflammatory cytokines and chemokines (TNFα, IL-6, IL-8, IL-1β). Microarray analysis of salmon injected with flagellin caused reproducible gene up-regulation of inflammatory cytokines, chemokines and receptors (IL-8, TNFRSF11B, IL-1R), antimicrobial peptides (hepcidin, cathelicidin), immune genes (C/EBP, thioredoxin, C-type lectin receptor B), complement genes (complement component C7 and C7-1), peptidases (MMP-9) and genes involved in the Ras/MAPK pathway (Ras-related proteins). Down-regulation of interesting immune genes also occurred including myxovirus resistance 1, clusterin-1 and LPS-induced TNF-α homolog. Some genes exhibited early, delayed or extended response over the sampling time and flagellin seemed to be the key component to eliciting a response. Flagellin was shown to induce innate immune responses in Atlantic salmon.
The papers of this thesis are not available in Munin:
1. Natasha A. Hynes, Clemens Furnes, Børge Nilsen Fredriksen, Tori Winther, Jarl Bøgwald, Atle N. Larsen, Roy A. Dalmo: 'Immune response of Atlantic salmon to recombinant flagellin', Vaccine (2011) vol. 29, no 44, pp 7678–7687. Available at http://dx.doi.org/10.1016/j.vaccine.2011.07.138
2. Natasha A. Hynes, Tiago S. Hori, Roy A. Dalmo and Matthew L. Rise: 'Functional genomics analysis of the immunological responses of Atlantic salmon (Salmo salar) spleen to injection with recombinant flagellin from Vibrio anguillarum' (manuscript)

Acute and long-term effects from petroleum discharges on temperate and Arctic Calanus species

Jensen, Louise Kiel — Thu, 10 Nov 2011 23:00:00 GMT

Jensen, Louise Kiel
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 fishing industry, as well as for maintaining a healthy ecosystem, petroleum related Environmental Risk Assessments (ERA) for the Barents Sea must be based on sound scientific knowledge of the special features of the Arctic ecosystem. In colder areas the physical behavior of oil is different compared to warmer areas. The lower temperature and lack of sun light during the Arctic winter slows down the natural physical weathering process of oil. In ERA in temperate areas the effects of exposure to the most volatile fraction of the oil are neglected due to short exposure time. However, in the Arctic the exposure to biota of this volatile fraction may be prolonged due to lower evaporation rates and the volatile fraction may be an important contributor to the overall adverse effect of an oil spill. Likewise, the exposure to the heavier oil fractions may be prolonged and knowledge on the long-term effects of exposure is essential. As an adaptation to the Arctic environment species found here have longer life spans, larger body sizes and higher lipid contents compared to temperate equivalent species. Thus Arctic species may accumulate contaminants over longer time and reach higher life time body levels. Meanwhile higher lipid content implies a higher affinity of lipophilic contaminants such as polycyclic aromatic hydrocarbons (PAHs). So, Arctic species may be exposed to oil compounds for a longer time because of the prolonged phycical presence and may, due to special adaptive features, be more efficient at accumulating oil contaminants. Today the knowledge of effects of oil contaminants on Arctic biota is limited, but growing. This thesis addresses a few of the research challenges in the field and provides knowledge on some effects of petroleum exposure to two copepod species; the sub-Arctic Calanus finmarchicus and the Arctic sibling species C. glacialis. First, Calanus was cultured for a generations under sub-Arctic conditions (Paper I). This work establishes that Calanus is suitable for ecological relevant long-term experiments. In an oil spill scenario, Arctic copepods and algae may be exposed to the more volatile fraction of the oil. Paper II provides data showing that the Arctic diatom species, Fragilariopsis oceanica, was the most sensitive species to exposure to the volatile hydrocarbon xylene. Further, the smaller, less lipid rich copepod species C. finmarchicus, was more sensitive compared to the true Arctic C. glacialis. Extrapolating these results to a spill situation, C. finmarchicus and C. glacialis populations would be affected by xylene exposure through both direct exposure (mortality) and indirectly through a decline in prey organisms (algae). Sub-lethal effects after long-term exposures to low concentrations of oil compounds may also be detected in C. finmarchicus and C. glacialis. Feeding was suppressed in C. finmarchicus after exposure to 7.0 µg PAHs l-1 for 11 days (Paper III). No significant effect on feeding was detected in C. glacialis exposed to 10.4 µg PAHs l-1 for 11 days. However, the hatching success of eggs laid by females exposed to 10.4 µg PAHs l-1 for two days was significantly reduced (Paper III). The long term effects of lipophilic PAHs in biota depend on the bioaccumulation capacity and internal concentrations of the various PAHs. Accumulation of lipophilic compounds is particularly important for the lipid rich Arctic species. Paper IV examines the uptake kinetics of two PAHs in C. finmarchicus and show that the accumulation of the lighter and less lipophilic compound, phenanthrene, is faster that the uptake of the heavier and more lipophilic benzo[a]pyrene (B[a]P). Equilibrium was reached for phenanthrene within 192 h exposure while no equilibrium was detected for B[a]P. The bioconcentration factor (BCF) was higher for B[a]P, reflecting the higher affinity for lipids of B[a]P compared to phenanthrene (Paper IV). So the heavier, more lipophilic PAH accumulates slower but to a higher concentration in C. finmarchicus. This thesis shows that not only acute but also long-term exposures may affect Arctic species. In addition, exposure duration may determine which compounds are accumulated by biota. Both indirect effects, such as decrease of food items, and direct effects, such as mortality, reduced feeding and reproduction failure may have implications for population development. These findings should be taken into consideration when developing ERA for the Barents Sea area.
Papers 1 and 2 of this thesis are not available in Munin:
1. Jensen, L.K., Carroll, JL., Pedersen, G., Hylland, K., Dahle, S. and Bakke, T.: 'A multigeneration Calanus finmarchicus culturing system for use in long-term oil exposure experiments', Journal of Experimental Marine Biology and Ecology (2006) 333: 71-78. Available at http://dx.doi.org/10.1016/j.jembe.2005.12.001
2. Jensen, L.K. and Carroll, JL.: 'Effects of the volatile petroleum component xylene on Arctic algae and zooplankton' (submitted manuscript to Marine Environmental Research).

Primary production and the relevance of small autotrophic and heterotrophic cells in marine arctic ecosystems

Hodal, Helene — Thu, 01 Dec 2011 23:00:00 GMT

Hodal, Helene
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 productive areas, especially the Barents Sea region, and a large part of arctic primary production occurs in these seasonally ice-covered regions. The relevance of small cells in arctic ecosystems has received increased attention the last two decades, and it is now accepted that the microbial food web play an important role also in the Arctic. To increase the knowledge on primary production and the relevance of small autotrophic and heterotrophic cells in the Arctic different field studies were conducted. Spring bloom dynamics (nutrients, phytoplankton, protozoans and in situ primary production) were investigated in Kongsfjorden (Svalbard) in April and May in 2002. During the multidisciplinary CABANERA-project three field campaigns in 2003-2005 to the marginal ice zone of the northern Barents Sea were conducted. Primary production was measured in situ for 24 hours at different stages of ice-edge blooms. Primary production and chlorophyll a measurements were fractionated in small (<10µm) and large cells (>10µm). During an expedition across the Arctic Ocean in August and September 2005 different biological parameters were measured (chlorophyll a, biogenic silica, particulate carbon and nitrogen, few zooplankton samples) together with the distribution of autotrophic and heterotrophic microbial biomass. Bacteria abundance was estimated using flow-cytometry and protists abundance was analyzed by epifluorescence microscopy after staining with DAPI. Protists were divided in different size categorize: < 2µm, 2-5µm, 5-10µm and 10-20µm. A seasonally study (January-September) of bacteria community structure and activity was conducted in a cold high latitude fjord (Balsfjord, northern Norway) in 2009 using fluorescence in situ hybridization (FISH) combined with microautoradiography (micro-FISH). In Kongsfjorden we found that the onset of the spring bloom was linked to the hydrographical situation during the sea ice break up. The peak of the spring bloom was found to vary between different years in both timing and intensity but will most probably occur between the middle-end of April and the middle of May. Primary production in 2002 persisted for a long time due to mixing with nutrient rich water masses. The ice edge phytoplankton bloom in the marginal ice zone of the northern Barents Sea was very heterogenic and no patterns in integrated primary production could be assigned to stages or latitudes. Subsurface (20-60m) primary production contributed with 24% to the total integrated primary production during ice edge blooms in the marginal ice zone, illustrating the importance of sampling in subsurface maxima. Small cells contributed with 46% to total primary production during ice edge blooms underlining the important role small cells can play as primary producers. Picoplankton (<2µm) abundance was high in the Arctic Ocean, and in the central part heterotrophic cells dominated (72%). Bacteria abundance was very low in the central part of the Arctic Ocean, but it is unknown whether this was caused by low growth rates or by high predation pressure. Bacteria were found to be highly active during summer in the Balsfjord underlining the important role they play in carbon turnover in the ocean. Bacteria belonging to Roseobacter were very active in assimilating DOM but they were not very abundant. This suggests that species specific predation may regulate the abundance of active bacteria. The main conclusion from the work included in this synthesis is that small cells are an important component of arctic food webs. Small cells need to be considered as important primary producers, also during spring blooms and ice edge blooms. We also found that bacteria need to be studied on single cell level to understand the underlying reasons for the dynamics that are observed on community levels.
Papers 2,3 and 4 are not available in Munin:
2. Hodal H and Kristiansen S.: 'The importance of small-celled phytoplankton in spring blooms at the marginal ice zone in the northern Barents Sea', Deep-Sea Research Part II (2008) 55: 2176-2185. Available at http://dx.doi.org/10.1016/j.dsr2.2008.05.012
3. Kristiansen S, Hodal H and Reigstad M.: 'Autotrophic and heterotrophic microbial biomass across the Arctic Ocean' (manuscript)
4. Hodal H, Kirchman D, Kristiansen S, Straza T.: 'Bacteria diversity and single-cell activity in a cold high latitude fjord (Balsfjord) from winter to late summer 2009' (manuscript)

Cellular responses induced by environmental stress factors in Arctic Seabird chicks : Responses of the antioxidant defense system and autophagic lysosomal processes related to contaminant exposure and food restriction

Hegseth, Marit Nøst — Mon, 28 Nov 2011 23:00:00 GMT

Hegseth, Marit Nøst
This PhD study has investigated how two commonly occurring environmental stress factors in the Arctic (periods with little food and exposure to halogenated organic contaminants) have had an impact on two important cellular defense mechanisms in Arctic seabirds. The antioxidant defense system and autophagic lysosomal responses in liver cells of Arctic seabird chicks have been studied. Samples were collected from three seabird species at Svalbard and Tromsø area: Black-legged kittiwake (Rissa tridactyla), northern fulmar (Fulmarus glacialis) and herring gull (Larus argentatus ), as well as samples from a feeding experiment with herring gull chicks. The findings show that there are major species differences, and that the antioxidant defense system and autophagic lysosomal responses in the seabird chicks are affected by factors such as diet, species-specific physiology and fasting, as well as high-grade contaminant exposure. Some of the effects of contaminant exposure were dose-dependent. The contaminant concentrations found in the birds in this study were relatively low. Hence, more pronounced effects could therefore be present in wild-living birds that have higher contaminant concentrations than birds in this study. Some of the cellular effects observed in this study have been associated with adverse health effects in other animal species. Additional studies of these cellular systems in seabirds are recommended in order to implement such analysis in regularly monitoring of seabird health status in the future and may contribute to improved management of the important seabird populations in these areas.
The papers of this thesis are not available in Munin:
1. Marit Nøst Hegseth, Lionel Camus, Lisa Bjørnsdatter Helgason, Raffaella Bocchetti, Geir Wing Gabrielsen and Francesco Regoli: 'Hepatic antioxidant responses related to levels of PCBs and metals in chicks of three Arctic seabird species', Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology (2011) 154: 28-35. Available at http://dx.doi.org/10.1016/j.cbpc.2011.02.008
2. Marit Nøst Hegseth, Lionel Camus, Stefania Gorbi, Francesco Regoli and Geir Wing Gabrielsen: 'Effects of exposure to halogenated organic compounds combined with dietary restrictions on the antioxidant defense system in herring gull chicks', Science of the Total Environment (2011) 409 (14):2717-24. Available at http://dx.doi.org/10.1016/j.scitotenv.2011.04.004
3. Marta K. Jansen, Marit Nøst Hegseth, Raffaella Bocchetti, Francesco Regoli, Geir W. Gabrielsen and Lionel Camus: 'Impact of Halogenated Organic Contaminant Exposure and Fasting on Antioxidant Defence System on the Kidney of Herring Gull Chicks' (manuscript)
4. Marit Nøst Hegseth, Francesco Regoli, Stefania Gorbi, Raffaella Bocchetti, Geir Wing Gabrielsen and Lionel Camus: 'Lysosomal and lipid-associated parameters in the livers of three species of arctic seabird chicks : Species differences and relationships with contaminant levels', Marine Pollution Bulletin (2011) 62(8): 1652-60. Available at http://dx.doi.org/10.1016/j.marpolbul.2011.06.011
5. Marit Nøst Hegseth, Stephania Gorbi, Raffaella Bocchetti, Geir Wing Gabrielsen, Francesco Regoli and Lionel Camus: 'Effects of contaminant exposure and food restriction on hepatic lysosomal and lipid associated parameters in Herring gull chicks' (submitted manuscript to Environmental Research)

Planktonic food webs in the Arctic Ocean : structure and function in contrasting seasons and physical settings across Fram Strait

Seuthe, Lena — Wed, 07 Dec 2011 23:00:00 GMT

Seuthe, Lena
This thesis investigates the structure and function of planktonic food webs at two sites between Greenland and the Svalbard Archipelago, covering a coastal ecosystem influenced by Atlantic water masses (Kongsfjorden, 78º N) and a more oceanic system off the East Greenlandic shelf, influenced by the outflow of Arctic water and sea ice from the Arctic Ocean (northwest Fram Strait, 75 - 80º N). In Kongsfjorden, a seasonal study was conducted with sampling at six occasions between March and December 2006. Logistical constrains prohibited a similar extensive seasonal investigation in the ice-covered waters of northwest Fram Strait. Sampling fell into the onset (April-May 2008) and end (September 2006/2007) of the productive season. All four studies investigated the stocks of pico- to micro-sized autotrophs and heterotrophs, i.e. heterotrophic bacteria, proto- and metazooplankton. Production rates of autotrophs and heterotrophic bacteria were measured in Kongsfjorden. Ratios of heterotrophic and autotrophic biomass (H:A) and of specific bacterial and primary production (µBac:µPhyto) allowed to asses the overall structure and function of the investigated planktonic food webs and to compare them to published data from other Arctic regions. The emerging picture provides three distinct food web modes, where mode A is characterized by H:A < 1 and µBac:µPhyto > 1, new production, and large-celled phytoplankton. Mode B and C are characterized by dominance of heterotrophs (H:A > 1), more regenerated production, and small-celled phytoplankton. The difference between mode B and C is a difference in the specific production ratio, with µBac:µPhyto smaller and larger 1, respectively. According to this scheme, Arctic plankton communities appear to prevail under mode B and C most of the year. In Kongsfjorden, e.g. five of the six months sampled fell under mode B and C, with mode C being typical for light-limited winter communities. From own and literature data, it is suggested that the food web mode controlling physical factors are the amount of incident photosynthetically active radiation (PAR), ice cover, nutrient concentration, and water column stability. Due to an approximately latitudinal change in these physical settings, the relative prevalence of the three food web modes changes from the marginal seas to the central Arctic Ocean, with mode A most likely being absent from the highest latitude waters. In general, Arctic plankton communities appear to sustain on average a 3-fold higher H:A biomass ratio for a given phytoplankton stock than the world’s coastal oceans, which may mainly be due to extensive import of long-lived copepods from sub-Arctic European seas through advection. It is argued that the large stock of heterotrophs plays a crucial role in structuring Arctic plankton communities, with the potential to prohibit phytoplankton bloom formation (mode A) through extensive grazing.
Paper 3 and 4 of this thesis are not available in Munin:
3. Seuthe L, Töpper B, Reigstad M, Thyrhaug R and Vaquer-Sunyer R: 'Microbial communities and processes in ice-covered Arctic waters of the northwestern Fram Strait (75 – 80ºN) during the vernal pre-bloom phase', Aquatic Microbial Ecology (2011) 64:253-266. Available at http://dx.doi.org/10.3354/ame01525
4. Svensen C, Seuthe L, Vasilyeva Y, Pasternak A and Hansen E: 'Zooplankton communities across Fram Strait in autumn : are small copepods and protozooplankton important? (in press in Progress in Oceanography).

Fishing for Advice : the case of the Norwegian Reference Fleet

Bjørkan, Maiken — Wed, 14 Dec 2011 23:00:00 GMT

Bjørkan, Maiken
This dissertation is about the changing relationship between science and society and the attempt to organize knowledge production and advisory processes in new ways: How can the relations between science and society be organized in a way that ensures sound advice as well as democratic ideals such as transparency and inclusion? Is it possible to relax the boundary between science and society without making it too blurry? How can arenas be built where scientists and stakeholders can cooperate effectively in knowledge production? How can lay people and their knowledge be included in advisory processes? To include stakeholders and at the same provide sound scientific advice, new solutions that require more openness in scientific processes are called for. In order to explore such solutions, the dissertation turn to the fisheries sector, where the top-down, traditional divide between science and other forms of knowledge is obvious: scientists are the experts with relevant and reliable knowledge for fisheries management. In recent decades, however, fisher stakeholders are identified as having valuable knowledge based on their experiences. Some also argue that fishers are experience based experts. But how to include them in a meaningful way, and how they are experts, are issues that are still open for debate. In Norway, the Institute of Marine Research runs a project called the Norwegian Reference Fleet, where fishers are invited to participate in knowledge production for advice. The Reference Fleet project provides a relevant framework to investigate empirically how to solve dilemmas related to the organization of knowledge production and advisory processes in more open, yet effective ways. The thesis makes a detailed account of how fishers are included by describing the knowledge chains in which they participate, and what happens to the knowledge as it is made to circulate and used for advice in fisheries management issues. Based on ethnographic methods, the Reference Fleets’ knowledge production has been followed wherever it has taken place: in laboratories and at sea; and in formal and informal settings. Theoretically, this thesis is supported by Science and Technology Studies, and Actor Network Theory in particular. The thesis aims to contribute to the on-going discourses on the 'lay expert' and how to open up science for stakeholders. It demonstrates that it is possible to include stakeholders in knowledge production for advice, and that lay people can become experts. However, it also argues that this hinges on participation at appropriate stages in the process, and that lay people, like scientists, needs access to both laboratories and authorization mechanisms in order to be included or be part of the expertise.

Species concepts and functional aspects of cold-water diatoms (Bacillariophyceae)

Degerlund, Maria — Mon, 17 Oct 2011 22:00:00 GMT

Degerlund, Maria
The choice of species concept when delineating phytoplankton species is decisive for our knowledge of species diversity and distribution, but will also affect our understanding of the functioning of marine ecosystems. This is particularly true for so-called cryptic species, which may show high degree of genetic and physiological heterogeneity although being morphologically similar. A precise species delimitation procedure appreciating the value of genotypic as well as phenotypic traits is therefore important. In this thesis, species concepts and functional aspects in abundant cold-water diatoms were investigated using biogeographic (species presence and abundance), taxonomic (morphological and molecular data), and functional (experimental physiological and metabolomics data) tools. A compilation of multiannual phytoplankton species abundance data gathered during the spring bloom period from north-east Atlantic and Arctic waters (68-80oN) revealed high similarities in associations of the most abundant species. Spring associations were dominated by the diatom Chaetoceros socialis and the prymnesiophyte Phaeocystis pouchetii. A corresponding investigation of the winter period in this area could not identify associations of actively growing, autotrophic phytoplankton species. Change in species composition and abundance in time could not be assessed due to lack of consistency and regularity in sampling. A high-resolution time series of phytoplankton distribution is therefore needed in this area. A case study of the so-called cosmopolitan diatom C. socialis was performed using strains from north-east Atlantic/Arctic and from Mediterranean waters. By applying a phylo-phenetic species concept the two geographical populations were found to be pseudo-cryptic. They were genetically distinct, but only slight morphological differences were observed, in this case in resting spore morphology. Furthermore, when cultivated at 2.5, 8 and 13oC, the two groups of strains were functionally different in terms of growth rates (doublings day-1), photosynthetic efficiency (maximum quantum yield), and metabolic profiles. Our results do not support the assumed cosmopolitan distribution of C. socialis and therefore the present taxonomy of this species will need revision. A taxonomic update of the pseudo-cryptic diatom formerly known as Skeletonema costatum indicated that the species present in northern Norwegian and Barents Sea waters is identical to S. marinoi. Due to reports of high genetic, metabolic, and physiological diversity within this species, a functional approach would be valuable for understanding the ecology of S. marinoi in this area. Integrated approaches combining taxonomic and functional variables are recommended for future taxonomic work on phytoplankton species. Similarly, phytoplankton ecologists are urged to acknowledge the high degree of hidden taxonomic and functional diversity present in several phytoplankton species. Functional diversity studies are suggested to be a useful spot for integration and eventual modelling phenotypic, genotypic and ecological species data. Ultimately, such an approach should be beneficial also at the ecosystem level.
The papers of this thesis are not available in Munin:
1. Degerlund M and Eilertsen HC: 'Main species characteristics of phytoplankton spring blooms in NE Atlantic and Arctic waters(68–80°N)', Estuaries and Coasts (2010) 33: 242-269. Available at http://dx.doi.org/10.1007/s12237-009-9167-7
2. Eilertsen HC and Degerlund M: 'Phytoplankton and light during the northern high-latitude winter', Journal of Plankton Research (2010) 32: 899-912. Available at http://dx.doi.org/10.1093/plankt/fbq017
3. Degerlund M, Huseby S, Zingone A, Sarno D and Landfald B: 'Functional diversity in cryptic species of Chaetoceros socialis Lauder (Bacillariophyceae)' (submitted paper to Journal of Plankton Research).
4. Huseby S, Degerlund M, Zingone A and Hansen, E: 'Metabolite fingerprinting and physiology of the cryptic diatom Chaetoceros socialis Lauder' (manuscript)

Converting sub-Arctic birch forests to spruce plantations : responses of predators and prey

Pedersen, Åshild Ønvik — Mon, 19 Apr 2010 22:00:00 GMT

Pedersen, Åshild Ønvik
In northern Norway large areas of sub-Arctic coastal birch forests have gradually been replaced by non-native spruce plantations during the last century. Spruce planting changes the forest floor vegetation and soil conditions, increase the amount of artificial edges and alter the forest landscape mosaics. Such tree species conversions are likely to reduce or increase suitable wildlife habitat, alter animal space use patterns, habitat selection and population and community dynamics. In a spatially extensive study design using live-trapping, snow tracking and baited track boards, I studied responses of individual predator species (red fox, pine marten, stoat, least weasel, lynx and corvids) and prey species (mountain hare, voles, common shrew and gallinaceous birds) and their interactions at three spatial scales ranging from within forest stands to landscape mosaics. I also included a study along the birch forest – alpine tundra ecotone to compare nest predation in native landscapes with those impacted by tree species conversion. In a 10 year observational trapping study of small mammals, I found much lower abundances of common shrew, red vole and field vole in spruce plantations compared to four birch forest types at stand scale. Autumn abundances were most impacted indicating that growth rates in the reproductive season were more influenced than winter declines. Species associated with productive forest habitats were most negatively impacted. Prevalence of endoparasites (helminths) in common shrew was highest in the rich birch forests and lowest in spruce plantations. In a 3 year observational study of an assemblage of ground dwelling vertebrates in winter, scale- and time dependent responses to spruce plantations were documented for the dominating species (red fox, stoat, mountain hare and voles). Small-scale affinity to plantation edges was found for most species. Habitat selection for and against spruce plantations at stand scale alternated profoundly among the years and species, however, in qualitatively similar patterns among the dominant species. At landscape scale only red fox was negatively related to amount of spruce plantations, while mountain hares exhibited annual shifts in occurrence relative to the amount of spruce. Predators and prey were related in time and space at the two smallest scales which may be explained by year- and stand-specific snow conditions affecting the predator-prey interactions within the community. In two experimental nest predation studies of 1 and 3 years, respectively, the omnipresent corvids were the dominant predators. The effects of spruce plantation edges and stands on predator prevalence were consistent with those of Einarsen et al. (2008), who concluded that edges and stand types had limited influence on spatial distribution of nest predators (Paper IV). Predator prevalence along the birch forest – II alpine tundra ecotone was remarkably consistent among locations and habitats. These results suggest that man-made and natural edges were not able to explain the overall high levels of predation observed. A decade of research on different wildlife species has documented clear responses to spruce plantations. Among the strongest effects is the pervasive negative impact on small mammal abundances and passerine bird communities in the studies of Hausner et al. (2002; 2003). Common for these species are their responses to habitat qualities at small spatial scales and they serve as prey for the predator communities. Reduction in abundance of key functional species, in particular the small mammals, is expected to influence the overall community structure and dynamics of vertebrates in this boreal forest ecosystem. The relatively weak responses documented at landscape scale (except for red fox) might change when young spruce plantations matures into old closed canopy monocultures. The findings emphasise the importance of maintaining a mix of tree species and high spatial heterogeneity of forest stands to prevent negative impacts on prey species abundances. The studies in this thesis have also shown that modern forestry can reinforce the effects of climate change. Changes in winter climate may modify snow conditions which in turn alter the role of forest stand mosaics in determining the structure of vertebrate communities. Moreover, the most probable cause of long-term declines in small mammal populations is changes in winter climate (Ims and Fuglei, 2005). These results comply with other studies reporting that modern forestry contribute to longterm declines of small mammal populations (Christensen and Hörnfeldt, 2006; Hörnfeldt et al., 2006; Christensen et al., 2008).
The papers of this thesis are not available in Munin:
1. Pedersen, Å.Ø., Yoccoz, N.G., Ims, R.A. and Sigurdsen, T.: 'Effects of non-native spruce plantations on small mammal communities in sub-Arctic birch forests', Forest Ecology and Management (2010) vol. 260, no. 3, pp. 331-338. Available at http://dx.doi.org/10.1016/j.foreco.2010.04.020
2. Sigurdsen, T., Pedersen, Å.Ø., Yoccoz, N.G., Haukisalmi, V. and Ims, R.A.: 'Are endoparasites of common shrew indicators of tree species conversion from sub-Arctic birch forest to spruce plantations?', European journal of forest research (2011) This is an online first paper, available at http://dx.doi.org/10.1007/s10342-011-0511-7
3. Pedersen,Å.Ø., Ims, R.A., Yoccoz, N.G., Hausner V.H. and Juell, K.H.: 'Scale-dependent responses of predators and their prey to spruce plantations in sub-Arctic birch forests in winter', Ecoscience (2010) 17(2):123-136. Available at http://dx.doi.org/10.2980/17-2-3333
4. Pedersen, Å.Ø., Yoccoz, N.G. and Ims, R.A.: 'Spatial and temporal patterns of artificial nest predation in mountain birch forests', European Journal of Wildlife Research (2009) vol.55: 371-384. Available at http://dx.doi.org/10.1007/s10344-009-0253-8
5. Klausen, K.B., Pedersen, Å.Ø., Yoccoz, N.G. and Ims, R.A.: 'Prevalence of nest predators in a sub-Arctic ecosystem', European journal of wildlife research (2010) vol. no.56:221–232. Available at http://dx.doi.org/10.1007/s10344-009-0304-1

Quantification and characterisation of residual blood in fish muscle : impact of slaughtering methods

Olsen, Stein Harris — Thu, 16 Jun 2011 22:00:00 GMT

Olsen, Stein Harris
Omorganisering i oppdrettsnæringen har ført til større og mer mekaniserte anlegg med høy slaktekapasitet. I dag kontrolleres normalt restblod i fiskefilet ved visuell inspeksjon. Dette er arbeidskrevende og innebærer subjektive evalueringer som muliggjør høy grad av unøyaktighet. Fargen på fiskemuskelen er også et viktig kriterium når kunder vurderer kvalitet, og disse fargeforandringene skyldes ofte restblod. Oppgaven belyser, i første omgang, de ulike enhetsoperasjonene ved slakting av fisk og hvilke effekter de har på selve utblødningen. I tillegg belyser den muligheten for å bruke en objektiv og hurtig målemetode for restblod i fiskemuskel, som er basert på visuell- og nærinfrarød spektroskopi. Restblod fører til store økonomiske tap for fiskeindustrien som følge av nedklassifisering. Området er lite belyst, og denne oppgaven søker å bidra med ny kunnskap rundt hvilke faktorer som påvirker mengden restblod i fiskemuskel. En kjemisk målemetode ble brukt som referanse og sammenlignet opp mot dagens visuelle inspeksjon samt en visuell- og nærinfrarød (VIS/NIR) spektroskopi metode. Sistnevnte innebærer måling av absorbsjon/refleksjon av lys fra bl.a. fargepigmentet hemoglobin, og metoden benyttes allerede i annen næringsmiddelindustri. Oppgaven viser at mengden blod i fiskemuskel påvirkes av stress før slakting, avlivingsmetoder, kjøling og lagring. Spesielt ble det funnet at bedøving ved bruk av slag før bløgging er optimalt med hensyn til restblod. Bruk av karbondioksid anbefales derimot ikke. VIS/NIR metoden anbefales ikke brukt industrielt, men metoden kan forbedres og automatiseres. Det foreslås å anvende avbildende VIS/NIR spektroskopi for å vurdere restblod i fiskefilet, med spektra fra fiske hemoglobin som referanse.; The quality of farmed fish is assessed according to multiple criteria including freshness, fat content, blood spots, flesh colour and gaping. Blood spots and residuals have become more frequent in fish fillets, after the reorganisation of the industry with a shift from small manually operated slaughterhouses to larger and more mechanized production lines. This has led to increased degree of rejection by consumers and financial losses. Today, blood residuals are mainly detected by manual visual inspection. However, this method is labour-intensive and involves subjective evaluation and thus a high degree of inaccuracy. The main objectives of this work was to find and establish an appropriate method to measure residual blood and blood spots in fish muscle and to study factors contributing to the problem in order to help the industry improve slaughter procedures. A chemical method used to quantify haem pigment in meat was adapted and established for quantifying blood in fish muscle. However, use of chemical methods involve toxic chemicals and are destructive to the product, they are therefore not suited in industrial food production. Nevertheless, the chemical method demonstrated that the amount of residual blood and blood spots were influenced both by pre-slaughter activity, killing procedures, chilling and storage conditions. In particular, percussive stunning prior to bleeding was proved better in terms of residual blood compared to carbon dioxide (CO2) stunning. In terms of fish welfare, CO2 anaesthesia is not recommended, as it creates vigorous activity among the fish before they were proper stunned. Pre-mortem activity also resulted in more blood in the fish muscle. The primary chromophore that gives the blood its characteristic colour is haemoglobin (Hb). Visual and near infrared (VIS/NIR) spectroscopy is a rapid technique and may be a valuable tool for the assessment of the blood residuals in fish fillets. Thus, with the chemical method as a reference, it was anticipated that VIS/NIR spectroscopy could be used to quantify haem pigment in whole fish fillets. A correlation between the VIS/NIR and chemical measurements of Hb in fish muscle was found. Most of the information regarding Hb in the fillet was found in the visible range (400–700 nm), but the 400–1100 nm ranges resulted in the lowest error of prediction. Even so, the error of prediction was still too high to recommend this method for industrial application. Detection limits and correlation of VIS/NIR measurements are influenced by the substance used for calibration. Mammalian Hb has been used as reference when measuring blood Hb. However, when comparing the optical spectra of mammalian and fish Hb, significant differences with respect to absorbance in the visible range (450-700 nm) was found. The fish Hb was also influenced by pH, resulting in deoxygenating and increased auto-oxidation and thus pH related differences in absorption spectres were evident. The knowledge gained through this work, regarding blood residuals in fish muscle, suggests measures in the slaughterhouse to improve bleeding. Added knowledge to improve online or automated VIS/NIR inspection of blood residuals was also gained. With regard to fish welfare and muscle quality, the stunning methods used today are disputed. Further studies are needed to improve these methods and their goal should be to satisfy both the requests for fish welfare and to improve muscle quality. Further studies should also focus on possible industrial application of using non-contact imaging spectroscopy to assess residual blood in fish fillets, using fish Hb spectra as a reference. In addition, studies investigating possible differences in the Hb spectra between fish spices are both academically interesting and may also have relevance if VIS/NIR spectroscopy is to be applied industrially.
The papers of this thesis are not available in Munin:
1. Olsen, S.H., Sørensen, N.K., Stormo, S.K. and Elvevoll, E.O.: 'Effect of slaughter methods on blood spotting and residual blood in fillets of Atlantic salmon (Salmo salar)', Aquaculture (2006) 258, 462-469. Available at http://dx.doi.org/10.1016/j.aquaculture.2006.04.047
2. Olsen, S.H., Sørensen, N.K., Larsen, R., Elvevoll, E.O. and Nilsen, H.: 'Impact of pre-slaughter stress on residual blood in fillet portions of farmed Atlantic cod (Gadus morhua) - Measured chemically and by Visible and Near-infrared spectroscopy', Aquaculture (2008) 284, 90-97. Available at http://dx.doi.org/10.1016/j.aquaculture.2008.07.042
3. Olsen, S.H. and Elvevoll, E.O.: 'A pH induced shift in the haemoglobin spectra – A spectrophotometeric comparison of fish (Gadus morhua) and mammalian haemoglobin', Journal of Agriculture and Food Chemistry (2011) 59 (4), pp 1415–1422. Available at http://dx.doi.org/10.1021/jf1036273