105 Works

Body size, light intensity and nutrient supply determine plankton stoichiometry in mixotrophic plankton food webs

Pei-Chi Ho, Chun-Wei Chang, Fuh-Kwo Shiah, Pei-Ling Wang, Chih-Hao Hsieh & Ken H. Andersen
Trophic strategy determines stoichiometry of plankton. In general, heterotrophic zooplankton have lower and more stable C:N and C:P ratios than photoautotrophic phytoplankton whereas mixotrophic protists, which consume prey and photosynthesize, have stoichiometry between zooplankton and phytoplankton. As trophic strategies change with cell size, body size may be a key trait influencing eukaryotic plankton stoichiometry. However, the relationship between body size and stoichiometry remains unclear. Here, we measured plankton size-fractionated C:N ratios under different intensities of...

Processed bed elevation picks from the POLARGAP radar survey across the Pensacola-Pole Basin (2015/2016)

Hugh Corr, Fausto Ferraccioli, Rene Forsberg, Tom Jordan, Jack Kohler, Kenichi Matsuoka, Arne Olesen & Carl Robinson
This dataset contains bed and surface elevation picks derived from airborne radar collected during the POLARGAP 2015/16 project funded by the European Space Agency (ESA) and with in-kind contribution from the British Antarctic Survey, the Technical University of Denmark (DTU), the Norwegian Polar Institute (NPI) and the US National Science Foundation (NSF). This collaborative project collected ~38,000 line-km of new aerogeophysical data using the 150MHz PASIN radar echo sounding system (Corr et al., 2007) deployed...

Fish resist temptation from junk food: State-dependent diet choice in reproductive Atlantic cod (Gadus morhua) facing seasonal fluxes of lipid-rich prey

Mikael Van Deurs, Anders Persson & Christian Jorgensen
In ecological sciences, animal diets are often simplified to “resources” or “caloric quantities”. However, in the present study, we investigated the optimal foraging strategy of Atlantic cod (Gadus morhua) when both macro- and micro-nutritional requirements are accounted for. Proteins cannot be synthesized from fatty acids, so the proteins for gonad development must come from other dietary sources. In addition, micronutrients are required in smaller quantities. For example, for cod, arachidonic acid (ARA) acts as a...

Data from: A predation cost to bold fish in the wild

Kaj Hulthén, Ben B. Chapman, P. Anders Nilsson, Lars-Anders Hansson, Christian Skov, Jakob Brodersen, Jerker Vinterstare & Christer Brönmark
Studies of predator-mediated selection on behaviour are critical for our understanding of the evolution and maintenance of behavioural diversity in natural populations. Consistent individual differences in prey behaviour, especially in the propensity to take risks (“boldness”), are widespread in the animal kingdom. Theory predicts that individual behavioural types differ in a cost-benefit trade-off where bolder individuals benefit from greater access to resources while paying higher predation-risk costs. However, explicitly linking predation events to individual behaviour...

Data from: Species integrity enhanced by a predation cost to hybrids in the wild

P. Anders Nilsson, Kaj Hulthén, Ben B. Chapman, Lars-Anders Hansson, Jakob Brodersen, Henrik Baktoft, Jerker Vinterstare, Christer Brőnmark & Christian Skov
Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of parental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post-zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide...

Data from: Historical DNA documents long distance natal homing in marine fish

Sara Bonanomi, Nina Overgaard Therkildsen, Anja Retzel, Rasmus Berg Hedeholm, Martin Wæver Wæver Pedersen, Dorte Meldrup, Christophe Pampoulie, Jakob Hemmer-Hansen, Peter Grønkjær & Einar Nielsen
The occurrence of natal homing in marine fish remains a fundamental question in fish ecology as its unequivocal demonstration requires tracking of individuals from fertilization to reproduction. Here, we provide evidence of long distance natal homing (> 1000 km) over more than sixty years in Atlantic cod (Gadus morhua), through genetic analysis of archived samples from marked and recaptured individuals. Using a high differentiation Single Nucleotide Polymorphism assay we demonstrate that the vast majority of...

Data from: All roads lead to home: panmixia of European eel in the Sargasso Sea

Thomas D Als, Michael M Hansen, Gregory E Maes, Martin Castonguay, Lasse Riemann, Kim Aarestrup, Peter Munk, Henrik Sparholt, Reinhold Hanel & Louis Bernatchez
European eels (Anguilla anguilla) spawn in the remote Sargasso Sea in partial sympatry with American eels (Anguilla rostrata), and juveniles are transported more than 5,000 kilometres back to the European and North African coasts. The two species have been regarded as classic textbook examples of panmixia, each comprising a single, randomly mating population. However, several recent studies based on continental samples have found subtle, but significant, genetic differentiation, interpreted as geographical or temporal heterogeneity between...

Maladaptive migration behaviour in hybrids links to predator-mediated ecological selection

Varpu Pärssinen, Kaj Hulthén, Christer Brönmark, Christian Skov, Jakob Brodersen, Henrik Baktoft, Ben Chapman, Lars-Anders Hansson & Anders Nilsson
1. Different migratory species have evolved distinct migratory characteristics that improve fitness in their particular ecological niches. However, when such species hybridize, migratory traits from parental species can combine maladaptively and cause hybrids to fall between parental fitness peaks, with potential consequences for hybrid viability and species integrity. 2. Here, we take advantage of a natural cross-breeding incident to study migratory behaviour in naturally occurring hybrids as well as in their parental species and explore...

Diatom defence: Grazer induction and cost of shell-thickening

Josephine Grønning & Thomas Kiørboe
1. Diatoms account for 40 % of the ocean primary production and play a key role in the oceans’ ability to sequester carbon. The evolutionary success of diatoms and their role in ocean biogeochemistry are related to the siliceous shell that provide partial protection against grazing. 2. The structure and function of phytoplankton communities are governed by environmental constraints and organismal trade-offs. Defence mechanisms may help explain the high diversity of phytoplankton (incl. diatoms) in...

Selective effects of small barriers on river-resident fish

Peter Jones, Toby Champneys, Jessica Vevers, Luca Börger, Jon Svendsen, Sofia Consuegra, Joshua Jones & Carlos Garcia De Leaniz
1. Habitat fragmentation is a principal threat to biodiversity and artificial river barriers are a leading cause of the global decline in freshwater biota. Whilst the impact of barriers on diadromous fish is well established, impacts on river-resident fish communities remain unclear, especially for low-head barriers. 2. We examined the movement of five contrasting freshwater fish (topmouth gudgeon, European minnow, stone loach, bullhead, and brown trout) in an experimental cascade mesocosm with seven pools separated...

Data from: Genome-wide signatures of local selection in the panmictic European eel

Jose Martin Pujolar, Magnus W. Jacobsen, Thomas D. Als, Jane Frydenberg, Kasper Munch, Bjarni Jónsson, Jianbo B. Jian, Ling Cheng, Gregory E. Maes, Louis Bernatchez & Michael M. Hansen
Next-generation sequencing and the collection of genome-wide data allow identifying adaptive variation and footprints of directional selection. Using a large SNP data set from 259 RAD-sequenced European eel individuals (glass eels) from eight locations between 34 and 64oN, we examined the patterns of genome-wide genetic diversity across locations. We tested for local selection by searching for increased population differentiation using FST-based outlier tests and by testing for significant associations between allele frequencies and environmental variables....

Data from: Insect temperature-body size trends common to laboratory, latitudinal and seasonal gradients are not found across altitudes

Curtis R. Horne, Andrew G. Hirst & David Atkinson
1. Body size affects rates of most biological and ecological processes, from individual performance to ecosystem function, and is fundamentally linked to organism fitness. Within species, size at maturity can vary systematically with environmental temperature in the laboratory and across seasons, as well as over latitudinal gradients. Recent meta-analyses have revealed a close match in the magnitude and direction of these size gradients in various arthropod orders, suggesting that these size responses share common drivers....

Data from: The ghost of introduction past: spatial and temporal variability in the genetic diversity of invasive smallmouth bass

Genevieve Diedericks, Romina Henriques, Sophie Von Der Heyden, Olaf Weyl & Cang Hui
Understanding the demographic history of introduced populations is essential for unravelling their invasive potential and adaptability to a novel environment. To this end, levels of genetic diversity within the native and invasive range of a species are often compared. Most studies, however, focus solely on contemporary samples, relying heavily on the premise that the historic population structure within the native range has been maintained over time. Here, we assess this assumption by conducting a three-way...

Data from: Estimating sensitivity of seabed habitats to disturbance by bottom trawling based on the longevity of benthic fauna

Adriaan D. Rijnsdorp, Stefan G. Bolam, Clement Garcia, Jan Geert Hiddink, Niels T. Hintzen, P. Daniel Van Denderen & Tobias Van Kooten
Bottom fishing such as trawling and dredging may pose serious risks to the seabed and benthic habitats, calling for a quantitative assessment method to evaluate the impact and guide management to develop mitigation measures. We provide a method to estimate the sensitivity of benthic habitats based on the longevity composition of the invertebrate community. We hypothesize that long-lived species are more sensitive to trawling mortality due to their lower pace of life (i.e. slower growth,...

Data from: Low genetic and phenotypic divergence in a contact zone between freshwater and marine sticklebacks: gene flow constrains adaptation

Susanne Holst Pedersen, Anne-Laure Ferchaud, Mia S. Bertelsen, Dorte Bekkevold & Michael Møller Hansen
Background: Distinct hybrid zones and phenotypic and genomic divergence is often observed between marine and freshwater threespine sticklebacks (Gasterosteus aculeatus). Nevertheless, cases also exist where marine-freshwater divergence is diffuse despite seemingly similar environmental settings. In order to assess what characterizes these highly different outcomes, we focused on the latter kind of system in the Odder River, Denmark. Here, a previous study based on RAD (Restriction site Associated DNA) sequencing found non-significant genome-wide differentiation between marine...

Data from: Stable coexistence of genetically divergent Atlantic cod ecotypes at multiple spatial scales

Halvor Knutsen, Per Erik Jorde, Jeffrey A. Hutchings, Jakob Hemmer-Hansen, Peter Grønkjær, Kris-Emil Mose Jørgensen, Carl Andre, Marte Sodeland, Jon Albretsen, Esben M. Olsen & Peter Grønkjaer
Coexistence in the same habitat of closely related yet genetically different populations is a phenomenon that challenges our understanding of local population structure and adaptation. Identifying the underlying mechanisms for such coexistence can yield new insight into adaptive evolution, diversification, and the potential for organisms to adapt and persist in response to a changing environment. Recent studies have documented cryptic, sympatric populations of Atlantic cod (Gadus morhua) in coastal areas. We analyzed genetic origin of...

Data from: Genomic analyses suggest adaptive differentiation of Northern European native cattle breeds

Astrid V. Stronen, Cino Pertoldi, Laura Iacolina, Haja N. Kadarmideen & Torsten N. Kristensen
Native domestic breeds represent important cultural heritage and genetic diversity relevant for production traits, environmental adaptation and food security. However, risks associated with low effective population size, such as inbreeding and genetic drift, have elevated concerns over whether unique within-breed lineages should be kept separate or managed as one population. As a conservation genomic case study of the genetic diversity represented by native breeds, we examined native and commercial cattle (Bos taurus) breeds including the...

Data from: Outlier SNP markers reveal fine-scale genetic structuring across European hake populations (Merluccius merluccius)

Ilaria Milano, Massimiliano Babbucci, Alessia Cariani, Miroslava Atanassova, Dorte Bekkevold, Gary R. Carvalho, Montserrat Espiñeira, Fabio Fiorentino, Germana Garofalo, Audrey J. Geffen, Einar E. Nielsen, Rob Ogden, Tomaso Patarnello, Marco Stagioni, Fausto Tinti & Luca Bargelloni
Shallow population structure is generally reported for most marine fish and explained as a consequence of high dispersal, connectivity and large population size. Targeted gene analyses and more recently genome-wide studies have challenged such view, suggesting that adaptive divergence might occur even when neutral markers provide genetic homogeneity across populations. Here, 381 SNPs located in transcribed regions were used to assess large- and fine-scale population structure in the European hake (Merluccius merluccius), a widely distributed...

Data from: Testing the Münch hypothesis of long distance phloem transport in plants

Michael Knoblauch, Jan Knoblauch, Daniel L Mullendore, Jessica A Savage, Benjamin A Babst, Sierra D Beecher, Adam C Dodgen, Kaare H Jensen & Noel Michele Holbrook
Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show...

Data from: Towards a mechanistic understanding of vulnerability to hook-and-line fishing: boldness as the basic target of angling-induced selection

Thomas Klefoth, Christian Skov, Anna Kuparinen & Robert Arlinghaus
In passively operated fishing gear, boldness-related behaviors should fundamentally affect the vulnerability of individual fish and thus be under fisheries selection. To test this hypothesis, we used juvenile common-garden reared carp (Cyprinus carpio) within a narrow size-range to investigate the mechanistic basis of behavioral selection caused by angling. We focused on one key personality trait (i.e., boldness), measured in groups within ponds, two morphological traits (body-shape and head-shape), and one life-history trait (juvenile growth capacity)...

Processed airborne radio-echo sounding data from the ICEGRAV survey covering the Recovery Catchment and interior Dronning Maud Land, East Antarctica (2012/2013)

Fausto Ferraccioli, Hugh Corr, Tom Jordan, Rene Forsberg, Kenichi Matsuoka, Anja Diez, Arne Olesen, Maria Ghidella, Andres Zakrajsek, Carl Robinson & Owen King
During the austral summer of 2012/13 a major international collaboration between Danish, US, UK, Norwegian and Argentinian scientists collected ~29,000 line km (equivalent to 464,317 km2) of aerogeophysical data over 132 hours of flight time and covering the previously poorly surveyed Recovery Glacier and Recovery Subglacial Lakes, as well as the area of Coats Land inboard from Halley VI using airborne survey systems mounted in Twin Otter aircraft. Our aircraft was equipped with dual-frequency carrier-phase...

Ancestral sperm ecotypes reveal multiple invasions of a non-native fish in northern Europe

Leon Green, Apostolos Apostolou, Ellika Faust, Kajsa Palmqvist, Jane W. Behrens, Jonathan N. Havenhand, Erica H. Leder & Charlotta Kvarnemo
For externally fertilising organisms in the aquatic environment, the abiotic fertilisation medium can be a strong selecting force. Among bony fishes, sperm are adapted to function in a narrow salinity range. A notable exception is the family Gobiidae, where several species reproduce across a wide salinity range. The family also contains several wide-spread invasive species. To better understand how these fishes tolerate such varying conditions, we measured sperm performance in relation to salinity from a...

Disparate movement behaviour and feeding ecology in sympatric ecotypes of Atlantic cod

Martin Lykke Kristensen
Co-existence of ecotypes, genetically divergent population units, is a widespread phenomenon, potentially affecting ecosystem functioning and local food web stability. In coastal Skagerrak, Atlantic cod (Gadus morhua) occur as two such co-existing ecotypes. We applied a combination of acoustic telemetry, genotyping and stable isotope analysis to 72 individuals to investigate movement ecology and food niche of putative local “Fjord” and putative oceanic “North Sea” ecotypes – thus named based on previous molecular studies. Genotyping and...

Data from: Convergent evolution of vascular optimization in kelp (Laminariales)

Sarah Tepler Drobnitch, Kaare H. Jensen, Paige Prentice & Jarmila Pittermann
Terrestrial plants and mammals, although separated by a great evolutionary distance, have each arrived at a highly conserved body plan in which universal allometric scaling relationships govern the anatomy of vascular networks and key functional metabolic traits. The universality of allometric scaling suggests that these phyla have each evolved an ‘optimal’ transport strategy that has been overwhelmingly adopted by extant species. To truly evaluate the dominance and universality of vascular optimization, however, it is critical...

Data from: Outlier loci detect intraspecific biodiversity amongst spring and autumn spawning herring across local scales

Riho Gross, Dorte Bekkevold, Sarah J. Helyar, Timo Arula & Henn Ojaveer
Herring, Clupea harengus, is one of the ecologically and commercially most important species in European northern seas, where two distinct ecotypes have been described based on spawning time; spring and autumn. To date, it is unknown if these spring and autumn spawning herring constitute genetically distinct units. We assessed levels of genetic divergence between spring and autumn spawning herring in the Baltic Sea using two types of DNA markers, microsatellites and Single Nucleotide Polymorphisms, and...

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  • Technical University of Denmark
  • Aarhus University
  • Swiss Federal Institute of Aquatic Science and Technology
  • Lund University
  • Bangor University
  • University of Copenhagen
  • Marine Research Institute
  • Grønlands Naturinstitut
  • Spanish Institute of Oceanography
  • University of Gothenburg