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Jeanine L Olsen - One of the best experts on this subject based on the ideXlab platform.
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thermal stress resistance of the brown alga Fucus serratus along the north atlantic coast acclimatization potential to climate change
Marine Genomics, 2014Co-Authors: Alexander Jueterbock, James A Coyer, Jeanine L Olsen, Spyros Kollias, Irina Smolina, Jorge M O Fernandes, Galice HoarauAbstract:Seaweed-dominated communities are predicted to disappear south of 45° latitude on North-Atlantic rocky shores by 2200 because of climate change. The extent of predicted habitat loss, however, could be mitigated if the seaweeds' physiology is sufficiently plastic to rapidly acclimatize to the warmer temperatures. The main objectives of this study were to identify whether the thermal tolerance of the canopy-forming seaweed Fucus serratus is population-specific and where temperatures are likely to exceed its tolerance limits in the next 200 years. We measured the stress response of seaweed samples from four populations (Norway, Denmark, Brittany and Spain) to common-garden heat stress (20 °C-36 °C) in both photosynthetic performance and transcriptomic upregulation of heat shock protein genes. The two stress indicators did not correlate and likely measured different cellular components of the stress response, but both indicators revealed population-specific differences, suggesting ecotypic differentiation. Our results confirmed that thermal extremes will regularly reach physiologically stressful levels in Brittany (France) and further south by the end of the 22nd century. Although heat stress resilience in photosynthetic performance was higher at the species' southern distributional edge in Spain, the hsp expression pattern suggested that this edge-population experienced reduced fitness and limited responsiveness to further stressors. Thus, F. serratus may be unable to mitigate its predicted northward shift and may be at high risk to lose its center of genetic diversity and adaptability in Brittany (France). As it is an important intertidal key species, the disappearance of this seaweed will likely trigger major ecological changes in the entire associated ecosystem.
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genomic scans detect signatures of selection along a salinity gradient in populations of the intertidal seaweed Fucus serratus on a 12 km scale
Marine Genomics, 2011Co-Authors: James A Coyer, Galice Hoarau, Gareth A Pearson, Catarina F Mota, A Juterbock, Tilman J Alpermann, Uwe John, Jeanine L OlsenAbstract:article i nfo 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.
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being abundant is not enough a decrease in effective population size over eight generations in a norwegian population of the seaweed Fucus serratus
Biology Letters, 2008Co-Authors: James A Coyer, Galice Hoarau, Kjersti Sjotun, Jeanine L OlsenAbstract:The brown alga Fucus serratus is a key foundation species on rocky intertidal shores of northern Europe. We sampled the same population off the coast of southern Norway in 2000 and 2008, and using 26 microsatellite loci, we estimated the changes in genetic diversity and effective population size (Ne). The unexpectedly low Ne (73-386) and Ne/N ratio (10-3-10-4), in combination with a significant decrease (14%) in allelic richness over the 8-year period, suggests an increased local extinction risk. If small Ne proves to be a common feature of F. serratus, then being abundant may not be enough for the species to weather future environmental changes.
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glacial refugia and recolonization pathways in the brown seaweed Fucus serratus
Molecular Ecology, 2007Co-Authors: Galice Hoarau, James A Coyer, Wytze T Stam, Jan Veldsink, Jeanine L OlsenAbstract:The last glacial maximum (20,000-18,000 years ago) dramatically affected extant distributions of virtually all northern European biota. Locations of refugia and postglacial recolonization pathways were examined in Fucus serratus (Heterokontophyta; Fucaceae) using a highly variable intergenic spacer developed from the complete mitochondrial genome of Fucus vesiculosus. Over 1,500 samples from the entire range of F. serratus were analysed using fluorescent single strand conformation polymorphism. A total of 28 mtDNA haplotypes was identified and sequenced. Three refugia were recognized based on high haplotype diversities and the presence of endemic haplotypes: southwest Ireland, the northern Brittany-Hurd Deep area of the English Channel, and the northwest Iberian Peninsula. The Irish refugium was the source for a recolonization sweep involving a single haplotype via northern Scotland and throughout Scandinavia, whereas recolonization from the Brittany-Hurd Deep refugium was more limited, probably because of unsuitable soft-bottom habitat in the Bay of Biscay and along the Belgian and Dutch coasts. The Iberian populations reflect a remnant refugium at the present-day southern boundary of the species range. A generalized skyline plot suggested exponential population expansion beginning in the mid-Pleistocene with maximal growth during the Eems interglacial 128,000-67,000 years ago, implying that the last glacial maximum mainly shaped population distributions rather than demography.
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origin of Fucus serratus heterokontophyta fucaceae populations in iceland and the faroes a microsatellite based assessment
European Journal of Phycology, 2006Co-Authors: James A Coyer, Galice Hoarau, Morten Skage, Wytze T Stam, Jeanine L OlsenAbstract:The common intertidal seaweed Fucus serratus was almost certainly introduced to Iceland and the Faroes by humans from Europe, as previous genetic studies have confirmed that life-history constraints preclude long-distance dispersal. Introduction must have occurred sometime in the 1,000 years between arrival of the first Icelandic settlers c. 900 AD and when the species was first noted in a phycological survey in 1900. We genotyped 19 populations from throughout northern Europe, Iceland, and the Faroes with seven microsatellite loci in order to identify the source or sources of the Icelandic/Faroese populations. Assignment tests indicated that the Smaskjaer area of the Oslofjorden in Norway was the source for the Icelandic populations and the HafnarfjorÐur area of Iceland was the likely source for the single Faroese population. The time of introduction to Iceland was probably during the 19th century, whereas introduction to the Faroes occurred during the late 20th century. Additionally, molecular data veri...
Hanne Dalsgaard Nielsen - One of the best experts on this subject based on the ideXlab platform.
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effects of temperature and salinity on germling development and fitness in the brown macroalga Fucus serratus l
Int. J. of Aquatic Science, 2018Co-Authors: Hanne Dalsgaard Nielsen, Soren Laurentius NielsenAbstract:Fucoid brown algae form extensive populations that dominate the intertidal and subtidal vegetation on temperate rocky shores. The persistence of populations of fucoid brown algae depends on their reproductive ability and the survival and growth of early life history stages (germlings) that are generally more susceptible to stressors than adults. In this study, the effects of temperature and salinity on germling development and fitness in the brown macroalgae Fucus serratus is assessed by studying rhizoid elongation, photosynthetic performance and survival in a matrix of four different temperatures and three salinities. It was hypothesized that both lower and higher than normal temperatures (12°C - 17°C) would constitute environmental stress and affect germling fitness, and that these effects would be exacerbated by sub-oceanic salinities below 32 psu. The results show that temperatures lower than the normal summer temperatures (6°C) have significant negative effects on both growth and survival as well as on photosynthesis, while there are no effects of higher than normal temperatures (22°C) alone. Sub-oceanic salinities affect growth and survival negatively, but only at the lowest salinity (18 psu), and have no effect on photosynthetic parameters. We conclude that higher water temperatures will not affect germling fitness, and thus F. serratus persistence, negatively, but low salinities and lower water temperatures will.
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juvenile life stages of the brown alga Fucus serratus l are more sensitive to combined stress from high copper concentration and temperature than adults
Marine Biology, 2014Co-Authors: Soren Laurentius Nielsen, Hanne Dalsgaard Nielsen, Morten Foldager PedersenAbstract:The combined effects of exposure to copper and temperature were investigated in adult specimens and germlings of the canopy-forming brown alga Fucus serratus. A matrix of four temperatures, 6, 12, 17 and 22 °C, and three concentrations of copper, 0, 100 and 1,000 nM total copper were used. Measured endpoints were growth rate, chlorophyll fluorescence parameters and for germlings also survival. The growth rate of adult specimens of F. serratus changed with increasing temperature. Growth tended to be negatively affected by high concentrations of copper when exposed to heat (22 °C) though not significantly so. The photosynthetic performance (i.e., chlorophyll fluorescence parameters: Fv/Fm, maximum electron transport rate (ETRmax) and maximum non-photosynthetic quenching (NPQmax) of adults was largely unaffected by both copper and temperature. Germling survival, growth rate and chlorophyll fluorescence parameters were affected by the combination of copper concentration and temperature. Increasing temperature led to reduced survival, increased rhizoid growth and higher Fv/Fm and ETRmax, whereas high copper concentration had a negative effect on the latter three endpoints. The negative effect of high copper concentration was amplified by high temperature. We conclude that juveniles of F. serratus are more susceptible to environmental stressors than adult specimens and recommend therefore including early life stages when assessing the risk of exposure to toxic compounds. Considering the response of adult specimens only may lead to false conclusions regarding the ecological impact of environmental stress.
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adaptation to high light irradiances enhances the photosynthetic cu2 resistance in cu2 tolerant and non tolerant populations of the brown macroalgae Fucus serratus
Marine Pollution Bulletin, 2010Co-Authors: Hanne Dalsgaard Nielsen, Soren Laurentius NielsenAbstract:Abstract The relationship between light acclimation and Cu 2+ tolerance was studied in two populations of Fucus serratus known to be naturally non-tolerant and tolerant to Cu 2+ . Acclimation to high irradiances increased the photosynthetic tolerance to Cu 2+ . The xanthophyll cycle was apparently not involved in protecting the photosynthetic apparatus against Cu 2+ toxicity, as results showed that Cu 2+ did not induce dynamic photoinhibition. The higher photosynthetic Cu 2+ resistance of high light algae did not result in increased growth. The excess energy acquired by high light-adapted algae appeared to be utilized in Cu 2+ defense mechanisms in the Cu 2+ non-tolerant population. The polyphenol content of the algae was reciprocal to the Cu T content, suggesting that polyphenol may be the primary Cu 2+ defense of non-tolerant low light algae, acting through secretion and extracellular chelating of Cu 2+ , while the compounds do not seem to be involved in the primary Cu 2+ tolerance mechanism in Cu 2+ tolerant algae.
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interactions between carbon black nanoparticles and the brown algae Fucus serratus inhibition of fertilization and zygotic development
Nanotoxicology, 2008Co-Authors: Hanne Dalsgaard Nielsen, Lorraine S Berry, Vicki Stone, Trevor R Burridge, Teresa F FernandesAbstract:The effects of manufactured carbon black (CB) nanoparticles on reproduction and early development of the marine brown algae Fucus serratus were studied. Results obtained indicated that effects of CB on sperm concentration and fertilization, body axis alignment, germination and rhizoid elongation were primarily physical. CB nanoparticles added to sperm suspension and embryo cultures, formed large agglomerates that removed sperm from suspension and reduced fertilization success at 100mgl−1. Correct alignment of the polar axis was reduced at 50mgl−1. From EM imaging there was no clear evidence of CB nanoparticle uptake in the zygotes. Instead zygotes were covered by agglomerates of CB nanoparticles that may have shaded for incident light that is crucial for alignment of the polar body axis. Germination and rhizoid elongation, both independent of light, were unaffected by CB nanoparticles.
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prior exposure to cu contamination influences the outcome of toxicological testing of Fucus serratus embryos
Marine Pollution Bulletin, 2005Co-Authors: Hanne Dalsgaard Nielsen, Colin Brownlee, Trevor R Burridge, Murray T BrownAbstract:Brown seaweeds are often employed in single species toxicity testing to study the association between the pollutant and the biota in contaminated marine habitats. We have used Fucus serratus (Phaeophyta) from one Cu resistant and one non-resistant population to evaluate the effect of prior exposure to metal pollution on toxicological endpoints. Analysis of comparative toxicity was conducted for embryo rhizoid elongation and adult relative growth rate (RGR). Algae that had previously been exposed to Cu expressed consistently lower levels of sensitivity to Cu than those that had no history of exposure to the pollutant. For both non-resistant and resistant populations rhizoid length was a more sensitive endpoint than adult RGR. While early life history stages of brown algae are generally regarded as being pollution-sensitive and inhibition of spore and embryo rhizoid elongation is frequently used as endpoints in bioassays, the test results may be affected by prior exposure of the parent algae to the pollutant. We conclude that the effect of prior exposure should be considered when comparing endpoints between studies and when selecting material for future testing.
Gray A Williams - One of the best experts on this subject based on the ideXlab platform.
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seasonal variation in a low shore Fucus serratus fucales phaeophyta population and its epiphytic fauna
Hydrobiologia, 1996Co-Authors: Gray A WilliamsAbstract:Seasonal variation in a Fucus serratus assemblage was studied on the Isle of Man, UK over a 13-month period. Algal cover varied greatly, related to shedding reproductive fronds and winter storms. Peak reproduction was recorded in the autumn. There was little change in density of plants, the population was dominated by a bank of germlings (<20 cm) and an adult mode between 50–70 cm. An indistinct third component of recruiting juveniles was present when gaps in the canopy formed. Seasonal variation in the algae was reflected in the population dynamics of the mobile epiphytes such as Littorina mariae and Lacuna pallidula, which exhibited annual life histories. Sessile species (such as bryozoans) utilized the algae year round, dominating the perennial stipes and lower fronds, which were not shed. Other species utilized the algae in a transient fashion: some feeding on the algae (e.g. Idotea), or other epiphytic animals (e.g. Nucella). Fucus serratus, therefore, provides a variety of spatially and temporally variable niches that explain the diversity of epiphytic animal species that exploit this alga.
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Seasonal variation in a low shore Fucus serratus (Fucales, Phaeophyta) population and its epiphytic fauna
Hydrobiologia, 1996Co-Authors: Gray A WilliamsAbstract:Seasonal variation in a Fucus serratus assemblage was studied on the Isle of Man, UK over a 13-month period. Algal cover varied greatly, related to shedding reproductive fronds and winter storms. Peak reproduction was recorded in the autumn. There was little change in density of plants, the population was dominated by a bank of germlings (
Colin Brownlee - One of the best experts on this subject based on the ideXlab platform.
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ca2 signals coordinate zygotic polarization and cell cycle progression in the brown alga Fucus serratus
Development, 2008Co-Authors: John H F Bothwell, J Kisielewska, Martin J Genner, Martin R Mcainsh, Colin BrownleeAbstract:Zygotes of the fucoid brown algae provide excellent models for addressing fundamental questions about zygotic symmetry breaking. Although the acquisition of polarity is tightly coordinated with the timing and orientation of the first asymmetric division-with zygotes having to pass through a G1/S-phase checkpoint before the polarization axis can be fixed-the mechanisms behind the interdependence of polarization and cell cycle progression remain unclear. In this study, we combine in vivo Ca2+ imaging, single cell monitoring of S-phase progression and multivariate analysis of high-throughput intracellular Ca2+ buffer loading to demonstrate that Ca2+ signals coordinate polarization and cell cycle progression in the Fucus serratus zygote. Consistent with earlier studies on this organism, and in contrast to animal models, we observe no fast Ca2+ wave following fertilization. Rather, we show distinct slow localized Ca2+ elevations associated with both fertilization and S-phase progression, and we show that both S-phase and zygotic polarization are dependent on pre-S-phase Ca2+ increases. Surprisingly, this Ca2+ requirement cannot be explained by co-dependence on a single G1/S-phase checkpoint, as S phase and zygotic polarization are differentially sensitive to pre-S-phase Ca2+ elevations and can be uncoupled. Furthermore, subsequent cell cycle progression through M phase is independent of localized actin polymerization and zygotic polarization. This absence of a morphogenesis checkpoint, together with the observed Ca2+-dependences of S phase and polarization, show that the regulation of zygotic division in the brown algae differs from that in other eukaryotic model systems, such as yeast and Drosophila.
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a tip high ca2 interdependent reactive oxygen species gradient is associated with polarized growth in Fucus serratus zygotes
Planta, 2008Co-Authors: Susana M Coelho, Colin Brownlee, John H F BothwellAbstract:We report the existence of a tip-high reactive oxygen species (ROS) gradient in growing Fucus serratus zygotes, using both 5-(and 6-) chloromethyl-2′,7′-dichlorodihydrofluorescein and nitroblue tetrazolium staining to report ROS generation. Suppression of the ROS gradient inhibits polarized zygotic growth; conversely, exogenous ROS generation can redirect zygotic polarization following inhibition of endogenous ROS. Confocal imaging of fluo-4 dextran distributions suggests that the ROS gradient is interdependent on the tip-high [Ca2+]cyt gradient which is known to be associated with polarized growth. Our data support a model in which localized production of ROS at the rhizoid tip stimulates formation of a localized tip-high [Ca2+]cyt gradient. Such modulation of intracellular [Ca2+]cyt signals by ROS is a common motif in many plant and algal systems and this study extends this mechanism to embryogenesis.
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prior exposure to cu contamination influences the outcome of toxicological testing of Fucus serratus embryos
Marine Pollution Bulletin, 2005Co-Authors: Hanne Dalsgaard Nielsen, Colin Brownlee, Trevor R Burridge, Murray T BrownAbstract:Brown seaweeds are often employed in single species toxicity testing to study the association between the pollutant and the biota in contaminated marine habitats. We have used Fucus serratus (Phaeophyta) from one Cu resistant and one non-resistant population to evaluate the effect of prior exposure to metal pollution on toxicological endpoints. Analysis of comparative toxicity was conducted for embryo rhizoid elongation and adult relative growth rate (RGR). Algae that had previously been exposed to Cu expressed consistently lower levels of sensitivity to Cu than those that had no history of exposure to the pollutant. For both non-resistant and resistant populations rhizoid length was a more sensitive endpoint than adult RGR. While early life history stages of brown algae are generally regarded as being pollution-sensitive and inhibition of spore and embryo rhizoid elongation is frequently used as endpoints in bioassays, the test results may be affected by prior exposure of the parent algae to the pollutant. We conclude that the effect of prior exposure should be considered when comparing endpoints between studies and when selecting material for future testing.
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cellular responses of developing Fucus serratus embryos exposed to elevated concentrations of cu2
Plant Cell and Environment, 2003Co-Authors: Murray T Brown, Hanne Dalsgaard Nielsen, Colin BrownleeAbstract:Elevated concentrations of Cu2+ can have inhibitory effects on early development in plants and algae by targeting specific cellular processes. In the present study the effects of elevated Cu2+ on developmental processes in embryos of the brown algae Fucus serratus (Phaeophyceae) were investigated. Elevated Cu2+ was shown to inhibit fixation of the zygotic polar axis but not its formation. Actin localization was unaffected by elevated Cu2+ but polarized secretion, which occurs downstream, was inhibited. Significant differences in tolerance to Cu2+ were observed for polarization and rhizoid elongation of embryos derived from adults from Cu2+-contaminated and uncontaminated locations. Moderate Cu2+ exposure inhibited the generation of cytosolic Ca2+ signals in response to hypo-osmotic shocks. In contrast, cytosolic Ca2+ was elevated by treatments with high [Cu2+] and this coincided with production of reactive oxygen species. The results indicate that direct effects on signalling processes involved in polarization and growth may in part explain complex, concentration-dependent effects of Cu2+ on early development.
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inter population differences in inherited copper tolerance involve photosynthetic adaptation and exclusion mechanisms in Fucus serratus
New Phytologist, 2003Co-Authors: Colin Brownlee, Hanne Dalsgaard Nielsen, Susana M Coelho, Murray T BrownAbstract:• A comparative study of copper (Cu) toxicity and tolerance in three populations of Fucus serratus was conducted by examining Cu2+ effects on various physiological parameters. • Chlorophyll fluorescence, oxygen evolution, copper content, and relative growth rate of embryos and adults were measured on Cu2+-exposed material. • Algae naturally exposed to elevated total Cu concentration (CuT), were more Cu2+ resistant than those from clean sites, as indicated by higher embryo and adult growth rates and lower copper contents. The Cu2+ tolerance of F. serratus is at least partly inherited and relies partly on metal exclusion. • There were inhibitory effects of Cu2+ on oxygen exchange rates in both tolerant and non-tolerant algae. By contrast to sensitive algae, the maximum efficiency of photosystem II (Fv/Fm), maximum fluorescence (Fm) and zero fluorescence (Fo) of resistant algae were unaffected by Cu2+, whereas decreased quantum yield (ΦPSII) and increased nonphotochemical quenching (NPQ) were most pronounced in resistant algae. Inhibitory effects of Cu2+ on ΦPSII may result in the excitation energy being dissipated through xanthophyll-dependent quenching mechanisms in tolerant algae. In nontolerant algae, lower energy dissipation may result in chlorophyll degradation.
James A Coyer - One of the best experts on this subject based on the ideXlab platform.
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thermal stress resistance of the brown alga Fucus serratus along the north atlantic coast acclimatization potential to climate change
Marine Genomics, 2014Co-Authors: Alexander Jueterbock, James A Coyer, Jeanine L Olsen, Spyros Kollias, Irina Smolina, Jorge M O Fernandes, Galice HoarauAbstract:Seaweed-dominated communities are predicted to disappear south of 45° latitude on North-Atlantic rocky shores by 2200 because of climate change. The extent of predicted habitat loss, however, could be mitigated if the seaweeds' physiology is sufficiently plastic to rapidly acclimatize to the warmer temperatures. The main objectives of this study were to identify whether the thermal tolerance of the canopy-forming seaweed Fucus serratus is population-specific and where temperatures are likely to exceed its tolerance limits in the next 200 years. We measured the stress response of seaweed samples from four populations (Norway, Denmark, Brittany and Spain) to common-garden heat stress (20 °C-36 °C) in both photosynthetic performance and transcriptomic upregulation of heat shock protein genes. The two stress indicators did not correlate and likely measured different cellular components of the stress response, but both indicators revealed population-specific differences, suggesting ecotypic differentiation. Our results confirmed that thermal extremes will regularly reach physiologically stressful levels in Brittany (France) and further south by the end of the 22nd century. Although heat stress resilience in photosynthetic performance was higher at the species' southern distributional edge in Spain, the hsp expression pattern suggested that this edge-population experienced reduced fitness and limited responsiveness to further stressors. Thus, F. serratus may be unable to mitigate its predicted northward shift and may be at high risk to lose its center of genetic diversity and adaptability in Brittany (France). As it is an important intertidal key species, the disappearance of this seaweed will likely trigger major ecological changes in the entire associated ecosystem.
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genomic scans detect signatures of selection along a salinity gradient in populations of the intertidal seaweed Fucus serratus on a 12 km scale
Marine Genomics, 2011Co-Authors: James A Coyer, Galice Hoarau, Gareth A Pearson, Catarina F Mota, A Juterbock, Tilman J Alpermann, Uwe John, Jeanine L OlsenAbstract:article i nfo 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.
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being abundant is not enough a decrease in effective population size over eight generations in a norwegian population of the seaweed Fucus serratus
Biology Letters, 2008Co-Authors: James A Coyer, Galice Hoarau, Kjersti Sjotun, Jeanine L OlsenAbstract:The brown alga Fucus serratus is a key foundation species on rocky intertidal shores of northern Europe. We sampled the same population off the coast of southern Norway in 2000 and 2008, and using 26 microsatellite loci, we estimated the changes in genetic diversity and effective population size (Ne). The unexpectedly low Ne (73-386) and Ne/N ratio (10-3-10-4), in combination with a significant decrease (14%) in allelic richness over the 8-year period, suggests an increased local extinction risk. If small Ne proves to be a common feature of F. serratus, then being abundant may not be enough for the species to weather future environmental changes.
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glacial refugia and recolonization pathways in the brown seaweed Fucus serratus
Molecular Ecology, 2007Co-Authors: Galice Hoarau, James A Coyer, Wytze T Stam, Jan Veldsink, Jeanine L OlsenAbstract:The last glacial maximum (20,000-18,000 years ago) dramatically affected extant distributions of virtually all northern European biota. Locations of refugia and postglacial recolonization pathways were examined in Fucus serratus (Heterokontophyta; Fucaceae) using a highly variable intergenic spacer developed from the complete mitochondrial genome of Fucus vesiculosus. Over 1,500 samples from the entire range of F. serratus were analysed using fluorescent single strand conformation polymorphism. A total of 28 mtDNA haplotypes was identified and sequenced. Three refugia were recognized based on high haplotype diversities and the presence of endemic haplotypes: southwest Ireland, the northern Brittany-Hurd Deep area of the English Channel, and the northwest Iberian Peninsula. The Irish refugium was the source for a recolonization sweep involving a single haplotype via northern Scotland and throughout Scandinavia, whereas recolonization from the Brittany-Hurd Deep refugium was more limited, probably because of unsuitable soft-bottom habitat in the Bay of Biscay and along the Belgian and Dutch coasts. The Iberian populations reflect a remnant refugium at the present-day southern boundary of the species range. A generalized skyline plot suggested exponential population expansion beginning in the mid-Pleistocene with maximal growth during the Eems interglacial 128,000-67,000 years ago, implying that the last glacial maximum mainly shaped population distributions rather than demography.
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origin of Fucus serratus heterokontophyta fucaceae populations in iceland and the faroes a microsatellite based assessment
European Journal of Phycology, 2006Co-Authors: James A Coyer, Galice Hoarau, Morten Skage, Wytze T Stam, Jeanine L OlsenAbstract:The common intertidal seaweed Fucus serratus was almost certainly introduced to Iceland and the Faroes by humans from Europe, as previous genetic studies have confirmed that life-history constraints preclude long-distance dispersal. Introduction must have occurred sometime in the 1,000 years between arrival of the first Icelandic settlers c. 900 AD and when the species was first noted in a phycological survey in 1900. We genotyped 19 populations from throughout northern Europe, Iceland, and the Faroes with seven microsatellite loci in order to identify the source or sources of the Icelandic/Faroese populations. Assignment tests indicated that the Smaskjaer area of the Oslofjorden in Norway was the source for the Icelandic populations and the HafnarfjorÐur area of Iceland was the likely source for the single Faroese population. The time of introduction to Iceland was probably during the 19th century, whereas introduction to the Faroes occurred during the late 20th century. Additionally, molecular data veri...
