NERC Life science Mass Spectrometry Facility

East Kilbride, United Kingdom

NERC Life science Mass Spectrometry Facility

East Kilbride, United Kingdom

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Fernandez R.,University of Aberdeen | Garcia-Tiscar S.,Autonomous University of Madrid | Santos M.B.,Spanish Institute of Oceanography | Lopez A.,CEMMA | And 4 more authors.
Marine Biology | Year: 2011

Skin and muscle from 43 bottlenose dolphins (38 juveniles/adults, 5 calves) stranded in NW Spain were analysed to determine whether stable isotope ratios (δ13C and δ15N) could be used to assess dietary variation, habitat segregation and population substructure. Results were compared with published stomach contents data. Stable isotope ratios from 17 known prey species were also determined. Isotope ratios of the main prey (blue whiting, hake) varied significantly in relation to fish body size. Dolphin calves showed significant heavy isotope enrichments compared to adult females. Excluding calves, δ15N decreased with increasing dolphin body size, probably related to an ontogenetic shift in diet towards species at lower trophic levels, e. g. on blue whiting as suggested by stomach content results. Bottlenose dolphins were divided into two putative populations (North, South) based on previous genetic studies, and values of δ13C and δ15N differed significantly between these two groups, confirming the existence of population structuring. © 2011 Springer-Verlag.


Knudsen R.,University of Tromsø | Siwertsson A.,University of Tromsø | Adams C.E.,University of Tromsø | Adams C.E.,University of Glasgow | And 3 more authors.
Evolutionary Ecology | Year: 2011

There is now strong evidence that foraging niche specialisation plays a critical role in the very early stages of resource driven speciation. Here we test critical elements of models defining this process using a known polymorphic population of Arctic charr from subarctic Norway. We test the long-term stability of niche specialisation amongst foraging predators and discuss the possibility that contrasting foraging specialists are exposed to differing selection regimes. Inter-individual foraging niche stability was measured by combining two time-integrated ecological tracers of the foraging niche (each individual's δ13C and δ15N stable isotope (SI) signatures and their food borne parasite fauna) with a short-term measure of foraging niche use (stomach contents composition). Three dietary subgroups of predators were identified, including zooplankton, gammarid and benthivore specialists foragers. Zooplanktivorous specialists had muscle low in δ 13C, a high abundance of parasites transmitted from pelagic copepods, a smaller head, longer snout and a more slender body-form than gammaridivorous specialist individuals which had muscle more enriched in δ 13C and high abundance of parasites transmitted from benthic Gammarus. Benthivorous individuals were intermediate between the other two foraging groups according to muscle SI-signals (δ13C) and loadings of parasites transmitted from both copepods and Gammarus. The close relationship between subgroups identified by stomach contents, time-integrated tracers of niche use (SI and parasites) and functional trophic morphology (niche adaptations) demonstrate a long-term temporally stable niche use of each individual predator. Differential habitat use and contrasting parasite communities and loadings, show differential exposure to different suites of selection pressures for different foraging specialists. Results also show that individual specialisation in trophic behaviour and thus exposure to different suites of selection pressures are stable over time, and thus provide a platform for disruptive selection to operate within this sympatric system. © 2010 Springer Science+Business Media B.V.


Votier S.C.,University of Plymouth | Bearhop S.,University of Exeter | Witt M.J.,University of Exeter | Inger R.,University of Exeter | And 2 more authors.
Journal of Applied Ecology | Year: 2010

The large amount of discards produced by commercial fisheries can have major impacts on marine predator populations: this abundant food may increase populations of some scavengers or decrease others via accidental bycatch. Yet, despite the conservation implications of discard practices, the ecology of individual scavengers is poorly understood. Here, we assess the influence of commercial fisheries' activity on the foraging behaviour of individual breeding northern gannets Morus bassanus. Using recent developments in stable isotope mixing models (Stable Isotope Analysis in R or SIAR) we estimate individual discard consumption. Using GPS tracking and the Vessel Monitoring System (VMS), we investigate behavioural responses to trawlers. Analysis of conventional diet samples, as well as stable isotope ratios of carbon and nitrogen in blood (plasma and cells), highlight marked individual differences in the proportion of fishery discards in the diet. Individual differences in foraging behaviour revealed by stable isotopes show evidence of both short-term consistency and behavioural flexibility. At-sea path tortuosity of 25 gannets (tracked using GPS loggers) revealed scale-dependent adjustments in response to VMS-derived fishing vessel locations, as well as to sea surface temperature, chlorophyll a concentration and copepod abundance. The results also indicate individual variability in behavioural response to trawlers. Individual differences in the amount of discards estimated from SIAR were negatively correlated with differences in foraging trip length and body condition, indicating potential fitness consequences. Synthesis and applications. The management of commercial fisheries and apex predators is a daunting task. Ultimately, reducing bycatch and removing dependency on discards remain key conservation priorities, but managers should also ensure that scavenging species have sufficient alternative food to meet their energetic needs, to ameliorate potential unforeseen knock-on consequences. The results of Stable Isotope Analysis (SIAR) reveal intra-population differences in discard consumption by gannets; differences that have impacts on foraging effort and body condition. The use of GPS tracking and Vessel Monitoring Systems (VMS) reveal that gannet at-sea behaviour is influenced by fishing vessels, although this also varies among individuals. A combination of SIAR, GPS tracking and VMS can be used to study fishery/scavenger interactions in detail at the individual level, to answer fundamental questions about scavenging behaviour. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.


Foote A.D.,Copenhagen University | Newton J.,NERC Life science Mass Spectrometry Facility | Avila-Arcos M.C.,Copenhagen University | Kampmann M.-L.,Copenhagen University | And 6 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2013

Niche variation owing to individual differences in ecology has been hypothesized to be an early stage of sympatric speciation. Yet to date, no study has tracked niche width over more than a few generations. In this study, we show the presence of isotopic niche variation over millennial timescales and investigate the evolutionary outcomes. Isotopic ratios were measured from tissue samples of sympatric killer whale Orcinus orca lineages from the North Sea, spanning over 10 000 years. Isotopic ratios spanned a range similar to the difference in isotopic values of two known prey items, herring Clupea harengus and harbour seal Phoca vitulina. Two proxies of the stage of speciation, lineage sorting of mitogenomes and genotypic clustering, were both weak to intermediate indicating that speciation has made little progress. Thus, our study confirms that even with the necessary ecological conditions, i.e. among-individual variation in ecology, it is difficult for sympatric speciation to progress in the face of gene flow. In contrast to some theoretical models, our empirical results suggest that sympatric speciation driven by among-individual differences in ecological niche is a slow process and may not reach completion. We argue that sympatric speciation is constrained in this system owing to the plastic nature of the behavioural traits under selection when hunting either mammals or fish. © 2013 The Author(s) Published by the Royal Society. All rights reserved.


Siwertsson A.,University of Tromsø | Knudsen R.,University of Tromsø | Praebel K.,University of Tromsø | Adams C.E.,University of Glasgow | And 2 more authors.
Evolutionary Ecology | Year: 2013

Natural populations often vary in their degree of ecological, morphological and genetic divergence. This variation can be arranged along an ecological speciation continuum of increasingly discrete variation, with high inter-individual variation at one end and well defined species in the other. In postglacial fishes, evolutionary divergence has commonly resulted in the co-occurrence of a pelagic and a benthic specialist. We studied three replicate lakes supporting sympatric pelagic and benthic European whitefish (Coregonus lavaretus (L.)) morphs in search for early signs of possible further divergence into more specialized niches. Using stomach content data (recent diet) and stable isotope analyses (time-integrated measure of trophic niche use), we observed a split in the trophic niche within the benthic whitefish morph, with individuals specializing on either littoral or profundal resources. This divergence in resource use was accompanied by small but significant differences in an adaptive morphological trait (gill raker number) and significant genetic differences between fish exploiting littoral and profundal habitats and foraging resources. The same pattern of parallel divergence was found in all three lakes, suggesting similar natural selection pressures driving and/or maintaining the divergence. The two levels of divergence (a clear and robust benthic - pelagic and a more subtle littoral - profundal divergence) observed in this study apparently represent different stages in the process of ecological speciation. © 2012 The Author(s).


Knudsen R.,University of Tromsø | Siwertsson A.,University of Tromsø | Adams C.E.,University of Tromsø | Adams C.E.,University of Glasgow | And 2 more authors.
Ecology of Freshwater Fish | Year: 2014

Two unconnected time-integrated tracers of niche use provided similar conclusions about individual foraging behaviour and niche adaptations (functional traits in head shape) within a subarctic lake population of Arctic charr (Salvelinus alpinus). Zooplanktivorous individuals mainly from the pelagic zone were characterised by having low δ13C values, high infections of the parasites transmitted by pelagic copepods (especially Diphyllobothrium spp.) and slender heads with long snouts. In contrast, fish individuals that had consumed benthic prey in the littoral zone were enriched in δ13C and had high abundances of parasites transmitted by Gammarus lacustris (Cyathocephalus truncatus and Cystidicola farionis) and a robust head shape. There were strong positive correlations between individual δ13C values and the abundance of the two parasite species transmitted by Gammarus, but a negative correlation between δ13C and the infection of copepod-borne parasites. The close relationships between diet variation (foraging behaviour), the time-integrated ecological tracers (SI and parasites) and functional trophic morphology (niche adaptations) evidently reflect long-term temporally stable niche use of each individual predator. The two independent time-integrated tracers both gave valuable information of specialised trophic behaviour at the individual level, which is an important basis for studies related to ecological (e.g., resource partitioning) and evolutionary (e.g., polymorphism) topics within a population. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.


Foote A.D.,University of Aberdeen | Foote A.D.,Copenhagen University | Vester H.,Ocean Sounds | Vester H.,German Primate Center | And 3 more authors.
Marine Mammal Science | Year: 2012

Epidermal skin samples from eastern North Atlantic killer whales, Orcinus orca, were analyzed for carbon and nitrogen stable isotope ratios. From those, comparisons within a data set of 17 samples collected from Tysfjord, Norway, in November suggested that diet is relatively specialized during this time period at this location. There were significant differences between a small set of samples from Iceland and those collected from Norway, which had all been assigned to the same population by a previous population genetics study. The results would be consistent with matrilines feeding on either the Norwegian or Icelandic stocks of Atlantic herring (Clupea harengus). There was no significant difference within Icelandic samples between those assigned to the population known to feed upon herring and those assigned to a population hypothesized to follow Atlantic mackerel (Scomber scombrus). The greatest differences were between the epidermal samples analyzed in this study and tooth and bone collagen samples from the North Sea that were analyzed previously, which also showed significantly more variation in isotopic ratios than found for skin samples. These differences could reflect differences in turnover rate, differences in diet-tissue fractionation and discrimination due to the amino acid composition of the different tissues, and/or greater competition promoting dietary variation between groups in the North Sea. © 2012 by the Society for Marine Mammalogy.


Evans K.L.,University of Sheffield | Newton J.,NERC Life science Mass Spectrometry Facility | Gaston K.J.,University of Sheffield | Gaston K.J.,University of Exeter | And 5 more authors.
Oikos | Year: 2012

How individuals colonising novel environments overcome the diverse suite of new selection pressures is a fundamental question in ecology and evolution. Urban environments differ markedly from the rural ones that they replace and successful colonisation of urban areas may therefore require local adaptation and phenotypic/genetic divergence from ancestral populations. Such a process would be facilitated by limited dispersal to and from the novel habitat. Here we assess divergence in migratory behaviour between seven pairs of urban and rural European blackbird Turdus merula populations along a 2800 km transect across Europe. This former forest specialist is now amongst the most abundant urban birds across most of its range. We use a stable isotope approach due to the lack of sufficient ringing data from multiple urban populations, and compare hydrogen isotopic ratios of tissues grown in the breeding (feathers) and wintering areas (claws) to derive an index of long distance migratory behaviour. We find a tendency for urban blackbirds to be more sedentary than rural ones at all sites and this divergence is particularly strong at the north-eastern limit of our transect, i.e. in Estonia and Latvia. These urban populations are those that have been established most recently (from the late 1930s to 1950s) implying that urbanisation can promote rapid ecological divergence. The increased sedentary behaviour of urban birds could promote further ecological divergence between rural and urban populations, such as the earlier breeding of urban blackbirds, and in some cases may contribute to their previously documented genetic divergence. © 2011 The Authors. Oikos © 2012 Nordic Society Oikos.


PubMed | University of Plymouth and NERC Life science Mass Spectrometry Facility
Type: Journal Article | Journal: Current biology : CB | Year: 2016

The Caribbean spiny lobster, Panulirus argus, is one of the most valuable fisheries commodities in the Central American region, directly employing 50,000 people and generating >US$450 million per year [1]. This industry is particularly important to small island states such as The Bahamas, which exports more lobster than any other country in the region [1]. Several factors contribute to this disproportionally high productivity, principally the extensive shallow-water banks covered in seagrass meadows [2], where fishermen deploy artificial shelters for the lobsters tosupplement scarce reef habitat [3]. The surrounding seabed communities are dominated by lucinid bivalve mollusks that live among the seagrass root system [4, 5]. These clams host chemoautotrophic bacterial symbionts in their gills that synthesize organic matter using reduced sulfur compounds, providing nutrition to their hosts [6]. Recent studies have highlighted the important role of the lucinid clam symbiosis in maintaining the health and productivity of seagrass ecosystems [7, 8], but their biomass also represents a potentially abundant, but as yet unquantified, food source to benthic predators [9]. Here we undertake the first analysis of Caribbean spiny lobster diet using a stable isotope approach (carbon, nitrogen, and sulfur) and show that a significant portion of their food (20% on average) is obtained from chemosynthetic primary production in the form of lucinid clams. This nutritional pathway was previously unrecognized in the spiny lobsters diet, and these results are the first empirical evidence that chemosynthetic primary production contributes to the productivity of commercial fisheries stocks.


PubMed | University of Porto, University of Coimbra, University of Lisbon, NERC Life science Mass Spectrometry Facility and 2 more.
Type: Journal Article | Journal: Oecologia | Year: 2016

Amongst migratory species, it is common to find individuals from different populations or geographical origins sharing staging or wintering areas. Given their differing life histories, ecological theory would predict that the different groups of individuals should exhibit some level of niche segregation. This has rarely been investigated because of the difficulty in assigning migrating individuals to breeding areas. Here, we start by documenting a broad geographical gradient of hydrogen isotopes (

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