20 results on '"Huseby, Siv"'
Search Results
2. Metabarcoding vs Microscopy - comparison of methods to monitor phytoplankton communities
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Andersson, Agneta, Zhao, Li, Brugel, Sonia, Figueroa, Daniela, Huseby, Siv, Andersson, Agneta, Zhao, Li, Brugel, Sonia, Figueroa, Daniela, and Huseby, Siv
- Abstract
Phytoplankton are used worldwide to monitor environmental status in aquatic systems. Long-time series of microscopy-analyzed phytoplankton are available from many monitoring stations. The microscopy-method is however time consuming and has short-comings. DNA metabarcoding has been suggested as an alternative method, but the consistency between different methods need further investigation. We performed a comparative study of microscopy and metabarcoding analyzing micro- and nanophytoplankton. For metabarcoding, 25-1000 ml seawater were filtered, DNA extracted and the 18S and 16S rRNA gene amplicons sequenced. For microscopy, based on the Utermöhl method we evaluated the use of three metrics: abundance, biovolume and carbon biomass. At the genus, species, and unidentified taxa level, metabarcoding generally showed higher taxonomic diversity than microscopy, and diversity was already captured at the lowest filtration volume tested, 25 ml. Metabarcoding and microscopy displayed relatively similar distribution pattern at the group level. The results showed that the relative abundances of the 18S rRNA amplicon at the group level best fitted the microscopy carbon biomass metric. The results are promising for implementing DNA metabarcoding as a complement to microscopy in phytoplankton monitoring, especially if databases would be improved and group level indexes could be applied to classify the environmental state of water bodies., Originally included in thesis in manuscript form.
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- 2023
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3. Key role of phosphorus and nitrogen in regulating cyanobacterial community composition in the northern Baltic Sea
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Andersson, Agneta, Höglander, Helena, Karlsson, Chatarina, and Huseby, Siv
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- 2015
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4. Functional diversity in cryptic species of Chaetoceros socialis Lauder (Bacillariophyceae)
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Degerlund, Maria, Huseby, Siv, Zingone, Adriana, Sarno, Diana, and Landfald, Bjarne
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- 2012
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5. Bacterioplankton growth
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Huseby, Siv, Wikner, Johan, Huseby, Siv, and Wikner, Johan
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Bacterioplankton growth rate is an indicator of the decomposition of organic matter and thereby trophic status of the Sea. The bacterioplankton metabolism accounts for about half of the mineralization of organic matter and thereby pelagic oxygen consumption. The bacterioplankton growth rate in deep waters indicates good trophic status in the off-shore Bothnian Bay and Bothnian Sea. Deep water growth rates were 67 % higher than at corresponding depths in the Atlantic Ocean, lacking excess enrichment. The decline that has earlier been reported has now ceased. During the last few years the growth rates has increased some and there is now no significant trends in any of the studied basins.
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- 2018
6. Naturtypsbestämning av utsjöstationer i Bottniska viken
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Huseby, Siv
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Ekologi ,miljöövervakning ,Ecology ,the Habitat Directive ,offshore monitoring stations ,Bottniska viken ,Natura 2000 ,Ospar ,Gulf of Bothnia ,EUNIS/HUB ,naturtypsbestämning ,Helcom - Abstract
Fyra utsjöstationer, som ingår i den nationella miljöövervakningen i Bottniska viken, har i denna undersökning naturtypsbestämts enligt art- och habitatdirektivets naturtyper och EUNIS/HUB. Stationerna provtogs med Van Veen huggare och den taxonomiska analysen utfördes på lab. För utsjö finns tre möjliga Natura 2000-naturtyper: 1110 sandbankar, 1170 rev och 1180 bubbelstrukturer. Ingen av de fyra stationerna passade beskrivningen av några av dessa tre möjligheter och klassades därmed inte som naturtyp enligt habitatdirektivet. Alla stationer hade lerigt sediment (>90%) med inslag av lite sand, silt eller noduler. Vid alla stationer dominerade amphipod-arterna Monoporeia affinis och/eller Pontoporeia femorata och stationerna bedömdes som ABH3N1 baltisk afotisk lerigt sediment dominerad av Monoporeia affinis och/ eller Pontoporeia femorata. Four offshore monitoring stations in the Gulf of Bothnia were in this study classified according to the Habitat Directive and EUNIS/ HUB. The stations were sampled with Van Veen grab and later taxonomically analyzed in the laboratory. For offshore stations there are three possible Natura2000 types: 1110 sandbanks, 1170 reefs and 1180 submarine structures made by leaking gases. None of the stations could fit the descriptions of any of these Natura 2000 habitat types. The sediment at all four stations was mostly clay (>90%) with elements of sand and silt and ferromanganese concretions. At all stations the amphipod species Monoporeia affinis and/or Pontoporeia femorata dominated the biomass. The EUNIS/HELCOM HUB classification for all stations was ABH3N1 Baltic aphotic muddy sediment dominated by Monoporeia affinis and/or Pontoporeia femorata.
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- 2017
7. Pelagial biologi/växtplankton
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Höglander, Helena, Skjevik, Ann-Turi, Karlsson, Chatarina, Huseby, Siv, Höglander, Helena, Skjevik, Ann-Turi, Karlsson, Chatarina, and Huseby, Siv
- Abstract
svensk miljöövervakning
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- 2016
8. Pelagial biologi/bakterieplankton
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Huseby, Siv and Huseby, Siv
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svensk miljöövervakning
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- 2016
9. Metabolic fingerprinting applied in diatom taxonomy
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Huseby, Siv and Eilertsen, Hans Christian
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DOKTOR-002 ,VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 ,VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497 - Abstract
The papers of this thesis are not available in Munin: 1. Eilertsen H.C., Huseby S., Degerlund, M., Eriksen, G.K., Ingebrigtsen, R.A. and Hansen, E.: 'Sample storage effects on reproducibility of direct infusion high-resolution mass spectrometry (HRMS) microalgae extract analysis', (manuscript submitted to Limnology and Oceanography Methods). 2. Huseby, S., Hansen, E., Degerlund, M., Eriksen, G. K., Ingebrigtsen, R.A and Eilertsen, H.C.: 'Chemical diversity of six northern diatoms', (manuscript submitted to Journal of Applied Phycology). 3. Degerlund, M., Huseby, S., Zingone, A., Sarno, D. and Landfald, B.: 'Functional diversity in cryptic species of Chaetoceros socialis Lauder (Bacillariophyceae)', Journal of Plankton Research (2012), vol. 34, no. 5:416-431. Available at http://dx.doi.org/10.1093/plankt/fbs004 4. Huseby S., Degerlund M., Zingone, A. and Hansen. E.: 'Metabolic fingerprinting reveals differences between northern and southern strains of the cryptic diatom Chaetoceros socialis', (manuscript in revision in European Journal of Phycology) The main aim of this thesis was to investigate if and how metabolic fingerprinting can be applied in diatom taxonomy. Even though both morphology and gene sequences have been shown to be appropriate tools in diatom taxonomy there are cases where these give contradicting results, like in the case of cryptic species. Cryptic species have similar morphology but are genetically different. Another issue with these two tools is that they do not offer much information about the function of a species, information that is interesting in light of for example ecology and management. Metabolomics investigates the metabolites synthesized by an organism. The metabolites synthesized at a certain moment in time will be a reflection of what genes are expressed at that time and will be a product of the organisms response to the environmental and biological conditions prevailing. Direct injection mass spectrometry was used to investigate the metabolic fingerprints of different, commonly occurring, northern diatom species. The method produces mass-to-charge ratios (markers) normally with a mass precision of four decimals. Reproducibility of the method was 80% with the direct injection method applied, using a decimal precision of 0.1. The results of the analysis showed that the different species shared between 26-67% of the total markers. Even species of the same genera showed a high diversity. The two species Chaetoceros furcellatus and Chaetoceros socialis only shared 30% of the total markers. For four out of six species the difference between species increased with decreasing temperature. The expected phylogeny of these six species could not be reflected by the metabolite data. Cryptic diversity has been documented within the so-called cosmopolitan species Chaetoceros socialis. We investigated this diversity between strains collected from two geographic areas; the northeast Atlantic and Arctic and from Mediterranean waters. Monoclonal cultures were cultivated at three different temperatures, and analyzed with the aid of morphology, LSU rRNA sequencing, growth rates, photosynthetic maximum quantum yield and metabolic fingerprinting. Comparison of gene sequences of the two groups showed an unequivocal difference, while only small morphological differences in spore morphology (not in the morphology of the vegetative cells) could be found between the two groups. At all three temperatures there were clear differences in growth and maximum quantum yield. The results from the metabolic fingerprinting also supported these findings. The clear genetic as well as functional differences does not support the cosmopolitan distribution of C. socialis and we therefore conclude that this species should be revised. The results, both from the comparison of metabolic fingerprinting between diatom species as well as within a pseudo cryptic diatom species, in my opinion, is in support of the use of metabolomics in diatom taxonomy. Our results underline the need of metadata, e.g. growth rates, in metabolomics studies. I also think that increased knowledge of functional traits of species, like metabolomics, could be implemented in ecological modeling, building a bridge between taxonomy and ecology. The results of this thesis are also relevant to bioprospecting. The higher chemical diversity between species found at the lower temperatures, would indicate that it could be beneficial to cultivate diatoms at low temperatures, close to zero, in search for bioactivities.
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- 2012
10. The effect of freeze/thaw cycles on reproducibility of metabolic profiling of marine microalgal extracts using direct infusion high-resolution mass spectrometry (HR-MS)
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Eilertsen, Hans Chr, Huseby, Siv, Degerlund, Maria, Eriksen, Gunilla K., Ingebrigtsen, Richard A., Hansen, Espen, Eilertsen, Hans Chr, Huseby, Siv, Degerlund, Maria, Eriksen, Gunilla K., Ingebrigtsen, Richard A., and Hansen, Espen
- Abstract
During normal sample preparation, storage in freezers and subsequent freeze/thaw cycles are commonly introduced. The effect of freeze/thaw cycles on the metabolic profiling of microalgal extracts using HR-MS was investigated. Methanolic extracts of monocultures of Arctic marine diatoms were analyzed immediately after extraction, after seven days of storage at -78 degrees C (one freeze/thaw cycle), and after additional seven days at -20 degrees C (two freeze/thaw cycles). Repeated direct infusion high-resolution mass spectrometry analysis of microalgae extracts of the same sample showed that reproducibility was ca. 90% when a fresh (unfrozen) sample was analyzed. The overall reproducibility decreased further by ca. 10% after the first freeze/thaw-cycle, and after one more freeze/thaw cycle the reproducibility decreased further by ca. 7%. The decrease in reproducibility after freeze-thaw cycles could be attributed to sample degradation and not to instrument variability.
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- 2014
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11. Strategi för kontrollerande övervakning av Bottenhavets vattendistrikt
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Andersson, Agneta, Hansen, Wenche, Wänstrand, Ingrid, Huseby, Siv, and Wikner, Johan
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marin ,toxikologi ,utformning ,ekologi ,mätprogram ,Miljövetenskap ,Bottenhavet ,Environmental Sciences - Abstract
Ett pelagialprogram har tagits fram för övervakning i relativt opåverkade referensområden i kustvattentyperna 16 t.o.m.19 i Bottemhavet. Programmet bör kunna ligga till grund för uppföljning av internationella, nationella och regionala miljömål samt följa upp ekologisk status. Den rumsliga variationen samt mellanårsvariationen hos pelagiala variabler i Bottenhavsområdet har använts som utgångspunkt för att beräkna provtagningsbehovet. Det föreslagna programmet innebär att mellan 48 och 60 provtagningar årsperiod, varefter ekologisk status kan bedömas. Designen gör det möjligt att med 80 % säkerhet bedöma ekologisk status med mätdata som ligger minst 20 % från klassgränserna. Mätprogrammet är designat för provtagningar -årsperiod. Stationer har slumpats ut i de olika typerna, och förslag på årliga provtagningslokaler anges i rapporten. Eftersom djupet vid de olika stationerna varierar, bör de flesta pelagiala variablerna provtas vid ett diskret djup i övre delen av vattenmassan, t.ex. 1 m djup. Av vetenskapliga och ekonomiska skäl är det viktigt att pelagialprogrammet samordnas för hela Bottenhavet. För mjukbottenfauna bedöms det befintliga integrerade programmet för trendanalys i Bottenhavet kunna tillgodose Vattendirektivets behov för kontrollerande övervakning i distriktet. Detta under förutsättning att Sundsvallsbuktens program fortsätter och att de nya nationella och regionala provtagningsområdena i södra Bottenhavet (Gräsö) etableras och drivs. Dimensioneringen av nuvarande nationellt och regionalt bottenfaunaprogram och områdesövervakning men har även visat sig vara väl anpassat för bedömningar inom ramen för Vattendirektivet. Enligt bedömningsgrunden bör minst 5 stationer användas för klassning av ekologisk status. Dessa stationer måste dock inte ligga inom samma vattenförekomst, utan kan vara lokaliserade i angränsande vattenförekomster. Den ekologiska statusen för mjukbottenfauna i enskilda vattenförekomster klassas genom extrapolering med hjälp av data från närbelägna områden med liknande bottenmiljö och påverkansgrad. Befintlig fiskebeståndsövervakning föreslås fortlöpa för att möjliggöra uppföljning av förändringar. En utökning av antalet övervakningsområden föreslås dock för att upprätta minst ett referensområde per inre och yttre kustvattentyp. En kombination av stratifierad och slumpmässig övervakning av fiskebestånden enligt nuvarande strategi föreslås, där djupintervallen stratifieras medan stationerna slumpas ut i respektive djupintervall. Provfiske och provtagning för miljögiftsanalys av fisk bör samordnas till samma provtagningstillfälle. Vidare bör den modell för samfinansiering och samordning som idag tillämpas av kustlänen i Bottniska viken för övervakning av fiskbestånd, samt och miljögiftsövervakning av fisk, fortlöpa även framöver. De ämnen som ingår i det pågående nationella programmet för miljögifter i fisk bör mätas även i de nya föreslagna områdena. När EU:s dotterdirektiv för prioriterade ämnen är beslutat och Vattenmyndigheterna fastställt miljökvalitetsnormer för särskilda förorenande ämnen, bör en översyn göras och ytterligare ämnen som är aktuella för Bottenhavet införlivas i övervakningsprogrammet. Miljögiftsövervakning i fisk bedöms kunna mätas med ett maximalt avstånd på 75 km mellan stationsområdena. Bedömning och extrapolera mätvärdena. För samtliga delprogram har en grova uppskattningar av kostnader för genomförandet gjorts. Projektet är ett samarbete mellan Länsstyrelserna i Norrbotten, Västerbotten, Västernorrland och Gävleborg och Umeå Marina Forskningscentrum och finansieras av Naturvårdsverket.
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- 2008
12. The Effect of Freeze/Thaw Cycles on Reproducibility of Metabolic Profiling of Marine Microalgal Extracts Using Direct Infusion High-Resolution Mass Spectrometry (HR-MS)
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Eilertsen, Hans, primary, Huseby, Siv, additional, Degerlund, Maria, additional, Eriksen, Gunilla, additional, Ingebrigtsen, Richard, additional, and Hansen, Espen, additional
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- 2014
- Full Text
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13. Chemical Diversity as a Function of Temperature in Six Northern Diatom Species
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Huseby, Siv, Degerlund, Maria, Eriksen, Gunilla K., Ingebrigtsen, Richard A., Eilertsen, Hans Chr., Hansen, Espen, Huseby, Siv, Degerlund, Maria, Eriksen, Gunilla K., Ingebrigtsen, Richard A., Eilertsen, Hans Chr., and Hansen, Espen
- Abstract
In this study, we investigate how metabolic fingerprints are related to temperature. Six common northern temperate diatoms (Attheya longicornis, Chaetoceros socialis, Chaetoceros furcellatus, Porosira glacialis, Skeletonema marinoi, and Thalassiosira gravida) were cultivated at two different temperatures, 0.5 and 8.5 °C. To exclude metabolic variations due to differences in growth rates, the growth rates were kept similar by performing the experiments under light limited conditions but in exponential growth phase. Growth rates and maximum quantum yield of photosynthesis were measured and interpreted as physiological variables, and metabolic fingerprints were acquired by high-resolution mass spectrometry. The chemical diversity varied substantially between the two temperatures for the tested species, ranging from 31% similarity for C. furcellatus and P. glacialis to 81% similarity for A. longicornis. The chemical diversity was generally highest at the lowest temperature.
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- 2013
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14. Mer fosfor ger mer cyanobakterier i norra Östersjön
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Andersson, Agneta, Karlsson, Chatarina, Huseby, Siv, Höglander, Helena, Andersson, Agneta, Karlsson, Chatarina, Huseby, Siv, and Höglander, Helena
- Abstract
I flera områden i norra Östersjön har cyanobakterierna ökat under de senaste tio till femton åren. I Bottenhavets och Egentliga Östersjöns kustområden ökar de kvävefixerande cyanobakterierna. I Bottenvikens utsjö är det den småcelliga och kolonibildande gruppen Chroococcales som blir fler. Förändringarna beror i flera fall på ökande halter av fosfor.
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- 2013
15. Metabolic fingerprinting reveals differences between northern and southern strains of the cryptic diatom Chaetoceros socialis
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Huseby, Siv, Degerlund, Maria, Zingone, Adriana, Hansen, Espen, Huseby, Siv, Degerlund, Maria, Zingone, Adriana, and Hansen, Espen
- Abstract
Morphology and molecular phylogeny constitute the structural elements of diatom taxonomy. These approaches do not, however, give information on the functioning of taxa. Additional methods to serve a more integrated and wide-ranging taxonomy have therefore been called for. Metabolic fingerprinting is one approach used within the field of metabolomics, often applied in classification of samples. Here we apply metabolic fingerprinting in a taxonomic study of a cryptic diatom species. Strains of the cosmopolitan diatom Chaetoceros socialis from two geographical areas; the north-east Atlantic and Arctic and the Gulf of Naples, were cultivated at three different temperatures; 2.5, 8 and 13°C. The strains from the two different geographical areas exhibited different growth rates as well as different photosynthetic efficiencies. Algal extracts, collected at the end of the growth experiments, were analysed by Ultra-Performance Liquid Chromatography High Resolution Mass Spectrometry. The two groups of strains were separated by principal component analysis of their metabolic fingerprints. Analysis of the data revealed both qualitative and quantitative differences in metabolite markers. These phenotypic differences reinforce differences also found for morphology, phylogenetic markers and growth rates, and point at different adaptive characteristics in organisms living under different temperature regimes.
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- 2012
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16. Skadliga algblomningar
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Karlsson, Bengt, Hajdu, Susanna, Andersson, Agneta, Huseby, Siv, Karlsson, Bengt, Hajdu, Susanna, Andersson, Agneta, and Huseby, Siv
- Published
- 2008
17. Chemical Diversity as a Function of Temperature in Six Northern Diatom Species
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Huseby, Siv, primary, Degerlund, Maria, additional, Eriksen, Gunilla, additional, Ingebrigtsen, Richard, additional, Eilertsen, Hans, additional, and Hansen, Espen, additional
- Published
- 2013
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18. Sommarens växtplanktonsamhälle har förändrats
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Hajdu, Susanna, Larsson, Ulf, Andersson, Agneta, Huseby, Siv, Skjevik, Ann-Turi, Hajdu, Susanna, Larsson, Ulf, Andersson, Agneta, Huseby, Siv, and Skjevik, Ann-Turi
- Abstract
Växtplanktonsamhällets sammansättning under sommaren har förändrats i alla havsområden under senare år. Exempelvis har filamentösa cyanobakterier ökat i Egentliga Östersjön. Den troligaste förklaringen är ändrade hydrografiska förutsättningar, så som ökad humustillförsel från land, försämrat ljusklimat, minskad salinitet och ökad temperatur orsakad av ändringar i klimatet.
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- 2007
19. Biovolumes and size-classes of phytoplankton in the Baltic Sea
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Olenina, I, Hajdu, S, Edler, L, Andersson, A, Wasmund, N, Busch, S, Göbel, J, Gromisz, S, Huseby, Siv, Huttunen, M, Jaanus, A, Kokkonen, P, Ledaine, I, Niemkiewicz, E, Olenina, I, Hajdu, S, Edler, L, Andersson, A, Wasmund, N, Busch, S, Göbel, J, Gromisz, S, Huseby, Siv, Huttunen, M, Jaanus, A, Kokkonen, P, Ledaine, I, and Niemkiewicz, E
- Published
- 2006
20. Metabolic fingerprinting reveals differences between northern and southern strains of the cryptic diatomChaetoceros socialis
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Huseby, Siv, primary, Degerlund, Maria, additional, Zingone, Adriana, additional, and Hansen, Espen, additional
- Published
- 2012
- Full Text
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