Marine Ecology Group

Bodø, Norway

Marine Ecology Group

Bodø, Norway
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Coyer J.A.,University of Groningen | Hoarau G.,Marine Ecology Group | Costa J.F.,University of Algarve | Hogerdijk B.,University of Groningen | And 6 more authors.
Molecular Phylogenetics and Evolution | Year: 2011

We examined 733 individuals of Fucus spiralis from 21 locations and 1093 Fucus vesiculosus individuals from 37 locations throughout their northern hemisphere ranges using nuclear and mitochondrial markers. Three genetic entities of F. spiralis were recovered. In northern and sympatric populations, the presence of " F. spiralis Low" in the mid-intertidal and " F. spiralis High" in the high-intertidal was confirmed and both co-occurred with the sister species F. vesiculosus. The third and newly-discovered entity, " F. spiralis South", was present mainly in the southern range, where it did not co-occur with F. vesiculosus. The South entity diverged early in allopatry, then hybridized with F. vesiculosus in sympatry to produce F. spiralis Low. Ongoing parallel evolution of F. spiralis Low and F. spiralis High is most likely due to habitat preference/local selection and maintained by preferentially selfing reproductive strategies. Contemporary populations of F. spiralis throughout the North Atlantic stem from a glacial refugium around Brittany involving F. spiralis High; F. spiralis South was probably unaffected by glacial episodes. Exponential population expansion for F. vesiculosus began during the Cromer and/Holstein interglacial period (300,000-200,000. yrs BP). Following the last glacial maximum (30,000-22,000. yrs BP), a single mtDNA haplotype from a glacial refugium in SW Ireland colonized Scandinavia, the Central Atlantic islands, and the W Atlantic. © 2010 Elsevier Inc.

Coyer J.A.,University of Groningen | Hoarau G.,Marine Ecology Group | Van Schaik J.,University of Groningen | Luijckx P.,University of Groningen | And 2 more authors.
Journal of Biogeography | Year: 2011

Aim We examined the phylogeography of the cold-temperate macroalgal species Fucus distichus L., a key foundation species in rocky intertidal shores and the only Fucus species to occur naturally in both the North Pacific and the North Atlantic. Location North Pacific and North Atlantic oceans (42° to 77°N). Methods We genotyped individuals from 23 populations for a mitochondrial DNA (mtDNA) intergenic spacer (IGS) (n=608) and the cytochrome c oxidase subunit I (COI) region (n=276), as well as for six nuclear microsatellite loci (n=592). Phylogeographic structure and connectivity were assessed using population genetic and phylogenetic network analyses. Results IGS mtDNA haplotype diversity was highest in the North Pacific, and divergence between Pacific haplotypes was much older than that of the single cluster of Atlantic haplotypes. Two ancestral Pacific IGS/COI clusters led to a widespread Atlantic cluster. High mtDNA and microsatellite diversities were observed in Prince William Sound, Alaska, 11years after severe disturbance by the 1989 Exxon Valdez oil spill. Main conclusions At least two colonizations occurred from the older North Pacific populations to the North Atlantic between the opening of the Bering Strait and the onset of the Last Glacial Maximum. One colonization event was from the Japanese Archipelago/eastern Aleutians, and a second was from the Alaskan mainland around the Gulf of Alaska. Japanese populations probably arose from a single recolonization event from the eastern Aleutian Islands before the North Pacific-North Atlantic colonization. In the North Atlantic, the Last Glacial Maximum forced the species into at least two known glacial refugia: the Nova Scotia/Newfoundland (Canada) region and Andøya (northern Norway). The presence of two private haplotypes in the central Atlantic suggests the possibility of colonization from other refugia that are now too warm to support F. distichus. With the continuing decline in Arctic ice cover as a result of global climate change, renewed contact between North Pacific and North Atlantic populations of Fucus species is expected. © 2010 Blackwell Publishing Ltd.

Coyer J.A.,University of Groningen | Hoarau G.,Marine Ecology Group | Pearson G.,University of Algarve | Mota C.,University of Algarve | And 4 more authors.
Marine Genomics | Year: 2011

Detecting natural selection in wild populations is a central challenge in evolutionary biology and genomic scans are an important means of detecting allele frequencies that deviate from neutral expectations among marker loci. We used nine anonymous and 15 EST-linked microsatellites, 362 AFLP loci, and several neutrality tests, to identify outlier loci when comparing four populations of the seaweed Fucus serratus spaced along a 12 km intertidal shore with a steep salinity gradient. Under criteria of at least two significant tests in at least two population pairs, three EST-derived and three anonymous loci revealed putative signatures of selection. Anonymous locus FsB113 was a consistent outlier when comparing least saline to fully marine sites. Locus F37 was an outlier when comparing the least saline to more saline areas, and was annotated as a polyol transporter/putative mannitol transporter - an important sugar-alcohol associated with osmoregulation by brown algae. The remaining loci could not be annotated using six different data bases. Exclusion of microsatellite outlier loci did not change either the degree or direction of differentiation among populations. In one outlier test, the number of AFLP outlier loci increased as the salinity differences between population pairs increased (up to 14); only four outliers were detected with the second test and only one was consistent with both tests. Consistency may be improved with a much more rigorous approach to replication and/or may be dependent upon the class of marker used. © 2010 Elsevier B.V.

Francisco S.M.,Eco Ethology Research Unit | Francisco S.M.,University of Porto | Faria C.,Eco Ethology Research Unit | Lengkeek W.,Marine Ecology Group | And 3 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2011

The study of the phylogeography of inshore fish from West Europe is revealing diverse geographical and demographical patterns. Some species conform to the phylogeographic patterns typical of terrestrial organisms, with marked signatures of the last glaciation and a decline of genetic diversity to the north of the species range. Other species, however, reveal no decline in diversity with latitude and signatures of expansions older than the last glaciation. The shanny Lipophrys pholis is a common intertidal resident fish in west European rocky shores. It is unable to leave the rocky stretch where it settled as a juvenile, so that dispersal depends entirely on the planktonic larval stage. These life-history and behavioural traits make the shanny an interesting species for phylogeographical analysis, as long-range movements by adults, which could blur historical signals, are absent. In this paper the phylogeography of L. pholis was studied using a fragment of the mitochondrial control region and one from the first intron of the S7 ribosomal protein gene. The European samples (ranging from SW Spain to the Netherlands) did not display population differentiation, isolation-by-distance or latitudinal declines in genetic diversity. Iberia was proposed as having operated as the main glacial refugium for the shanny. The genealogy of the European population showed that the largest expansion detected was older than the last glaciation, with lineages persisting from the early Pleistocene, which does not conform to colonisation by a few founders in the current interglacial. It is argued that if fishes have very large population sizes and high dispersal rates, populations can efficiently track climatic shifts so that little or no genetic structure remains after each range expansion and latitudinal gradients of genetic diversity tend to be weak or non-existent. © 2011 Elsevier B.V.

Martin O.,Santa Clara University | Cardenas R.,Santa Clara University | Guimarais M.,Marine Ecology Group | Penate L.,Santa Clara University | And 2 more authors.
Astrophysics and Space Science | Year: 2010

We continue former work on the modeling of potential effects of Gamma Ray Bursts on Phanerozoic Earth. We focus on global biospheric effects of ozone depletion and model the spectral reduction of light by NO2 formed in the stratosphere. We also illustrate the current complexities involved in the prediction of how terrestrial ecosystems would respond to this kind of burst. We conclude that more biological field and laboratory data are needed to reach even moderate accuracy in this modeling. © Springer Science+Business Media B.V. 2009.

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