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See detailOccurrence of legacy and emerging organic pollutants in whitemouth croakers from Southeastern Brazil
Pizzochero da Costa, Ana Carolina ULiege; de la Torre, Adrian; Sanz, Paloma et al

in Science of the Total Environment (in press)

The whitemouth croaker (Micropogonias furnieri) is one of the most commercially important species along the Atlantic coast of South America. Moreover, some of its biological traits (long life span ... [more ▼]

The whitemouth croaker (Micropogonias furnieri) is one of the most commercially important species along the Atlantic coast of South America. Moreover, some of its biological traits (long life span, inshore feeding, high trophic position) make this species a suitable sentinel of coastal pollution. Here, we investigated contamination by multiple legacy and emerging organic pollutants, such as brominated and chlorinated flame retardants, polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), in whitemouth croakers from two estuaries (Guanabara and Sepetiba Bays) located in industrialized and urbanized areas in Rio de Janeiro State, Southeastern Brazil. Furthermore, we assessed how biological and ecological features could explain the observed contamination patterns. Regarding brominated flame retardants, concentrations of polybrominated diphenyl ethers (PBDEs) varied from 7.6 to 879.7 pg g-1 wet weight (w.w.), with high contribution of tetra-, penta-, hexa- and deca-BDEs. The sum of chlorinated flame retardants (dechlorane-related compounds, ΣDRC) ranged from <LOD to 41.1 pg g-1 w.w., mostly represented by Dechlorane 603 and Dechlorane Plus (DP). Concentrations of PCDDs and PCDFs varied from <LOD to 1.7 pg g-1 w.w., while the Toxic Equivalent (TEQ-PCDD/Fs) levels ranged from 0.1 to 0.2 pg g-1 w.w. Positive correlations between δ15N and concentrations of tri-, tetra- and penta-BDEs, as well as ΣDRC, DP and anti-DP isomers suggested that ecological factors (namely biomagnification along the food web) influence contamination of whitemouth croakers in the estuaries studied. Moreover, the sum of PBDEs (ΣPBDE), tri- and tetra-BDEs concentrations were negatively correlated with fish size, suggesting that depuration by fishes and/or habitat shift throughout the whitemouth croaker’s life cycle might also influence concentrations. Overall, our study emphasized the need for further investigations to help understand the complex patterns of bioaccumulation and biomagnification that seem to exist in Southeastern Brazil. [less ▲]

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See detailModelling species response to climate change in sub-Antarctic islands: echinoids as a case study for the Kerguelen Plateau
Saucède, Thomas; Guillaumot, Charlène; Michel, Loïc ULiege et al

in CCAMLR Science (in press)

In the Kerguelen Islands, the multiple effects of climate change are expected to impact coastal marine habitats. Species distribution models (SDM) can represent a convenient tool to predict the ... [more ▼]

In the Kerguelen Islands, the multiple effects of climate change are expected to impact coastal marine habitats. Species distribution models (SDM) can represent a convenient tool to predict the biogeographic response of species to climate change but biotic interactions are not considered in these models. Nevertheless, new species interactions can emerge in communities exposed to environmental changes and the structure of biotic interactions is directly related to the potential resilience of ecosystems. Trophic interaction studies can help predict species vulnerability to environmental changes using carbon (δ13C) and nitrogen (δ15N) stable isotope ratios to generate trophic models. Using new available data inputs, we generated robust SDM and trophic interaction models to assess the potential response and sensitivity of three echinoid species to future worst-case scenarios of environmental change in the Kerguelen Plateau region. The two modelling approaches provide contrasting insights into the potential responses of each species to future environmental changes with both approaches identifying Abatus cordatus to be particularly vulnerable due to its narrow ecological niche and endemism to near-shore areas. Coupling insights gained from trophic niche ecology with species distribution modelling represents a promising approach that can improve our understanding and ability to predict the potential responses of species to future habitat changes. [less ▲]

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See detailIncreased sea ice cover alters food web structure in East Antarctica
Michel, Loïc ULiege; Danis, Bruno; Dubois, Philippe et al

in Scientific Reports (2019), 9

In recent years, sea ice cover along coasts of East Antarctica has tended to increase. To understand ecological implications of these environmental changes, we studied benthic food web structure on the ... [more ▼]

In recent years, sea ice cover along coasts of East Antarctica has tended to increase. To understand ecological implications of these environmental changes, we studied benthic food web structure on the coasts of Adélie Land during an event of unusually high sea ice cover (i.e. two successive austral summers without seasonal breakup). We used integrative trophic markers (stable isotope ratios of carbon, nitrogen and sulfur) to build ecological models and explored feeding habits of macroinvertebrates. In total, 28 taxa spanning most present animal groups and functional guilds were investigated. Our results indicate that the absence of seasonal sea ice breakup deeply influenced benthic food webs. Sympagic algae dominated the diet of many key consumers, and the trophic levels of invertebrates were low, suggesting omnivore consumers did not rely much on predation and/or scavenging. Our results provide insights about how Antarctic benthic consumers, which typically live in an extremely stable environment, might adapt their feeding habits in response to sudden changes in environmental conditions and trophic resource availability. They also show that local and/or global trends of sea ice increase in Antarctica have the potential to cause drastic changes in food web structure, and therefore to impact benthic communities. [less ▲]

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See detailEnvironmental drivers of sea stars feeding ecology in the Southern Ocean
Le Bourg, Baptiste ULiege; Blanchard, Alice; Danis, Bruno et al

Conference (2019, May 06)

The Antarctic continent and the surrounding Southern Ocean undergo strong and contrasted impacts of climate change. In the Western Antarctic Peninsula, sea ice cover and ice season duration are decreasing ... [more ▼]

The Antarctic continent and the surrounding Southern Ocean undergo strong and contrasted impacts of climate change. In the Western Antarctic Peninsula, sea ice cover and ice season duration are decreasing, presumably in relation with increased air and water temperature and northwesterly winds originating from the also warming subtropical Pacific. In contrast, despite increased air and deep water temperatures, sea ice cover and ice season duration are increasing in other Antarctic regions. This is possibly linked with ocean stratification due to freshwater inputs from the melting continental ice. These changes are likely to impact marine communities and food webs of the Southern Ocean. Sea stars (Echinoderms: Asteroidea) are an important group of the Southern Ocean benthos. Compared to other organisms, they seem to have relatively high physiological tolerance to warming. However, they could be indirectly affected by climate change, notably through quantitative and qualitative modifications of food availability. In this context, the aim of this study was to infer the trophic diversity of sea stars of the Southern Ocean to assess their potential trophic plasticity regarding food web changes. Thanks to collaborative networking and valorization of museum samples, Sea stars samples taken in summer in various regions around the Antarctic continent with different types of environment (Antarctic or Subantarctic, deep-sea or coastal, presence of sea ice or not) were obtained. Stable isotopes ratios of C (denoted δ13C) and N (denoted δ15N) were then analysed in the tegument of sea stars in order to investigate their trophic ecology. Isotopic niches metrics were also computed to assess differences of trophic diversity between regions. Variability in stable isotope ratios and isotopic niche metrics revealed strong differences in sea star feeding ecology between and within locations, possibly in relation with differences in environmental conditions, notably sea ice coverage and dynamics. For example, on the continental shelf of Antarctic South Shetland Islands, small isotopic niches could indicate that sea stars exploit a food web based on a common basal food source and exhibit a "trophic continuum". In this context, absence of sea ice before and during the sampling period could have limited the number of available food sources. By contrast, on the continental shelf of the Antarctic Marguerite Bay or in the Subantarctic South Georgia Island, sea stars had large isotopic niches that suggest that they could exploit one or several food webs based on more than one food source, and exhibited strong trophic segregation. In Marguerite Bay, this could be linked with progressive sea ice melting, which allows export of both sea ice materials and blooming phytoplankton to the benthic compartment. In South Georgia, on the other hand, oligotrophic conditions and thus reduced availability of phytoplankton are more likely to explain this pattern. Ultimately, this project helps us understanding which ecological processes determine how an ecologically important animal group copes with environmental modifications linked to climate change. This research was funded by the Belgian Federal Science Policy Office (BELSPO) in the framework of the vERSO  and RECTO project (rectoversoprojects.be). [less ▲]

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See detailUnravelling the evolutionary processes that shaped the diversity of the amphipod genus Eusirus in the Southern Ocean
Salabao, Louraine ULiege; Frederich, Bruno ULiege; Lepoint, Gilles ULiege et al

Poster (2019, May)

Various evolutionary processes greatly influenced by the geological and climatic history shaped the diversity of the current Antarctic marine fauna. In the past, these Antarctic species have survived ... [more ▼]

Various evolutionary processes greatly influenced by the geological and climatic history shaped the diversity of the current Antarctic marine fauna. In the past, these Antarctic species have survived different glacial cycles through dispersal to refugia, and/or adaptations to novel abiotic and biotic conditions. With the increasing temperatures in the polar regions, marine fauna is currently faced with three possible outcomes: adaptation, migration or extinction. Based on how these organisms were able to survive environmental changes in the past will allow us to predict their future response. In this study, amphipods of the genus Eusirus are as model organisms as knowledge on their ecology and biogeography is still very limited. The evolutionary history of Eusirus amphipods is phylogenetically reconstructed through time with molecular data. DNA sequence data are obtained by sequencing the complete mitochondrial genomes, using a combination of skimming sequencing and long-range PCRs amplicons of different Eusirus species. Mitochondrial data will be complemented with additional sequence data from nuclear genes. Time-calibrated phylogenies will be used as basis for plotting ecological and trophic data generated by stable isotope analyses as well as morphological information. By combining data from time-calibrated phylogenies as well as from ecology and morphology, we aim to understand the evolutionary processes that led to the current diversity of Eusirus amphipods. [less ▲]

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See detail‘Homemade’: the phenotypic diversity of coral reef damselfish populations is driven by the local environment
Chen, Chia-Ting; Robitzch, Vanessa; Sturaro, Nicolas ULiege et al

in Biological Journal of the Linnean Society (2019), 127

Documenting phenotypic variation among populations is crucial for our understanding of micro-evolutionary processes. To date, the quantification of trophic and morphological variation among populations of ... [more ▼]

Documenting phenotypic variation among populations is crucial for our understanding of micro-evolutionary processes. To date, the quantification of trophic and morphological variation among populations of coral reef fish at multiple geographical scales remains limited. This study aimed to quantify diet and body shape variation among four populations of the damselfish Dascyllus abudafur living in different environmental conditions from the central Red Sea and from Madagascar. Stomach content analyses showed that one adaptive response of D. abudafur inhabiting turbid waters is a trophic shift from almost exclusive zooplanktivory to a diet consisting of planktonic and benthic prey. Our morphometric data reveal differences in cephalic profile and body shape among populations, in agreement with this variation in trophic strategy. Isotopic diversity and body shape disparity vary among populations and we thus demonstrate that coral reef fish populations are not equal in terms of phenotypic diversity among sites and regions. Finally, our comparative analysis reveals that the main axes of body shape variation among populations are shared at both small (Red Sea sites) and large (Madagascar and Red Sea sites) spatial scales. This study raises new questions about the factors governing the direction of response to selection in this fish species. [less ▲]

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See detailRevealing the trophic ecology of black corals through stable isotope analysis
Cabrera, Patricia M.; Terrana, Lucas; Lepoint, Gilles ULiege et al

Poster (2019, March 13)

Antipatharians, also known as black corals, are colonial organisms that show a high heterogeneity in their colony morphology and polyp sizes. This morphological diversity likely sustains varied ... [more ▼]

Antipatharians, also known as black corals, are colonial organisms that show a high heterogeneity in their colony morphology and polyp sizes. This morphological diversity likely sustains varied adaptations and various trophic strategies, such as variation in feeding behavior and diet composition. In some areas, black coral colonies are so dense that they dominate the community, forming black coral beds where different species co-occur. Although studies on the trophic ecology of black corals are few, they are considered to feed on zooplankton and a research, currently in progress, demonstrates that diverse species present different trophic niches, supporting the hypothesis that black corals differ in their trophic diversity. Here we are aiming to identify their diet and thus the potential diverse feeding strategies of black corals. For this purpose, we will study the stable isotopic composition of carbon, nitrogen and sulfur of black corals living in shallow waters of the northern limit of the Great Reef of Toliara, Madagascar. Tissues of black corals and three potential food sources (i.e. plankton, suspended particulate organic matter and benthic particulate organic matter) were sampled. Samples were collected at two sites, within the same bed, during the dry and wet seasons, in order to assess spatio-temporal variations. Further, plankton was sampled at bottom and sea surface, at night and day and categorized according to six size classes. Data generated will be analyzed using Bayesian modeling tools in R (SIAR, Stable Isotope Mixing Model and tRophicPosition) to determine the proportional contribution of food sources in the coral's diet and their trophic position. Results will reveal a new perspective on the feeding ecology of black corals, filling the numerous gaps on their trophic ecology, a knowledge that may explain how these species coexist in the same environment and that is needed to develop future conservation policies. [less ▲]

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See detailUnderstanding the biodiversity and evolutionary history of the amphipod genus Eusirus in the Southern Ocean
Salabao, Louraine ULiege; Frederich, Bruno ULiege; Lepoint, Gilles ULiege et al

Poster (2019, March 13)

The diversity of the Antarctic marine fauna has been shaped by various evolutionary processes (dispersals, diversifications, extinctions), which were greatly influenced by the geological and climatic ... [more ▼]

The diversity of the Antarctic marine fauna has been shaped by various evolutionary processes (dispersals, diversifications, extinctions), which were greatly influenced by the geological and climatic history of the region. Some Antarctic lineages are descendants of Gondwanan ancestors and arose by vicariance during the progressive breakup of Gondwana, which ultimately led to the complete geographical isolation of the Antarctic continent. The Plio-Pleistocene glacial cycles have been inferred to act as a “diversity pump” on the Antarctic continental shelf. Allopatric speciation of less dispersive organisms could have resulted from the isolation of populations in ice-free refugia during the glacial advances. These glacial cycles were often suggested to have influenced the diversification of numerous complexes of closely related and morphologically very similar Antarctic species. The continuous discovery of such (pseudo-) cryptic species in the Southern Ocean suggests that its biodiversity is currently greatly underestimated. Such species complexes have been found in the amphipod genus Eusirus. In a preliminary phylogeny (COI and 28S) of the whole genus, some Antarctic nominal Eusirus species are composed of genetically distant clades, suggesting putative new species. In this study, we will sequence complete mitochondrial genomes, using a combination of skim sequencing and long-range PCRs of different Eusirus species, to which sequence data from nuclear (28S, ITS2) will be added. By greatly increasing character sampling as well as taxon sampling (including Antarctic and non-Antarctic species) compared to preliminary studies, we intend to reconstruct a robust phylogeny of the genus. Based on this DNA dataset and the phylogeny, we aim to (1) provide a better estimate of the actual diversity within the genus, using various DNA-based species delimitation methods (GMYC, PTP, 4 theta rule and ABDG) and; (2) provide a better understanding of their evolutionary history: where does the Antarctic clade come from? Did Eusirus species disperse in and/or out of the Antarctic shelf at any time of their evolutionary history? Were there periods of increased diversification during their evolution on the shelf and how do these relate to the geological/glacial history of the region? [less ▲]

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See detailTemporal trends of mercury differ across three northern white-tailed eagle (Haliaeetus albicilla) subpopulations
Sun, Jiachen; Bustnes, Jan Ove; Helander, Björn et al

in Science of the Total Environment (2019)

The spatiotemporal trends of mercury (Hg) are crucial for the understanding of this ubiquitous and toxic contaminant. However, uncertainties often arise from comparison among studies using different ... [more ▼]

The spatiotemporal trends of mercury (Hg) are crucial for the understanding of this ubiquitous and toxic contaminant. However, uncertainties often arise from comparison among studies using different species, analytical and statistical methods. The long-term temporal trends of Hg exposure were reconstructed for a key sentinel species, the white-tailed eagle (Haliaeetus albicilla). Body feathers were sampled from museum collections covering 150 years in time (from 1866 to 2015) from West Greenland (n=124), Norway (n=102), and Sweden (n=87). A significant non-linear trend was observed in the Norwegian subpopulation, with a 60% increase in exposure occurring from 1866 to 1957 followed by a 40% decline until 2015. In the Swedish subpopulation, studied at a later period, the Hg exposure showed a drastic decline of 70% from 1967 to 2011. In contrast, no significant trend could be observed in the Greenland subpopulation. The additional analysis of dietary proxies (δ13C and δ15N) in general increased performance of the temporal trend models, but this was dependent on the subpopulation and study period. The downward trend of Hg coincided with the decreasing δ13C and δ15N in the Norwegian subpopulation, suggesting a potential dietary mitigation of Hg contamination. Hg exposure in both the Greenland and Norwegian subpopulations was consistently below the suggested threshold for adverse health effects (40 μg g−1), while the maximum exposure in the Swedish subpopulation was distinctively elevated (median: 46.0 μg g−1) and still remains well above natural background concentrations (maximum 5 μg g−1). [less ▲]

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See detailRiver habitat homogenisation enhances trophic competition and promotes individual specialisation among young of the year fish
Latli, Adrien; Michel, Loïc ULiege; Lepoint, Gilles ULiege et al

in Freshwater Biology (2019), 64(3), 520-531

In large rivers, the success of ontogenic development of fish is mainly influenced by resource availability and by the possibility of species to adapt their diet (i.e. trophic niche). Human have ... [more ▼]

In large rivers, the success of ontogenic development of fish is mainly influenced by resource availability and by the possibility of species to adapt their diet (i.e. trophic niche). Human have drastically modified freshwater habitats, notably for navigation purposes. Such modifications may drastically affect food availability for young of the year (YOY) fish and, consequently, influence their ability to reach the adult age. In the River Meuse, a decrease of fish abundance is thought to be linked to a drastic decrease of phytoplankton biomass. In this context of lowering phytoplankton biomass, we quantified the trophic niches of three cyprinid species (common bleak Alburnus alburnus, chub Squalius cephalus, and roach Rutilus rutilus) and one percid species (European perch Perca fluviatilis) at various stages of development, in order to estimate the influence of river channelization in the intra and interspecific competitions. It was done using stable isotope analysis in two reaches of the River Meuse differing by their degree of regulation. We hypothesized that habitat heterogeneity increases YOY abundance over time by offering more alternative resources which reduce food competition, notably during the early period of life. Our study provides evidence that the River Meuse flow and depth regulation significantly impacted the abundance and taxonomic diversity of YOY. In the context of low planktonic biomass, most YOY relied on benthic food sources. In the heavily channelized reach, between-stages competition and low resource diversity increased the diet partition between cyprinid larvae and forced a part of individuals to consume non-optimal energetic food sources such as aquatic vegetation. On the other hand, in the less channelized reach, larvae displayed a generalist feeding habit focusing on energetic prey such as different taxa of macroinvertebrates, suggesting that the diversity of habitat reduces the food competition within and between stages and the predation risk. Developing a sustainable and integrated river management may be useful for protecting biodiversity and restoring ecosystem function, in order to improve the ecological potential of regulated rivers. [less ▲]

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See detailPlasma concentrations of organohalogenated contaminants in white-tailed eagle nestlings – The role of age and diet
Løseth, M. E.; Briels, N.; Eulaers, I. et al

in Environmental Pollution (2019), 246

Concentrations of organohalogenated contaminants (OHCs) can show significant temporal and spatial variation in the environment and wildlife. Most of the variation is due to changes in use and production ... [more ▼]

Concentrations of organohalogenated contaminants (OHCs) can show significant temporal and spatial variation in the environment and wildlife. Most of the variation is due to changes in use and production, but environmental and biological factors may also contribute to the variation. Nestlings of top predators are exposed to maternally transferred OHCs in the egg and through their dietary intake after hatching. The present study investigated spatial and temporal variation of OHCs and the role of age and diet on these variations in plasma of Norwegian white-tailed eagle (Haliaeetus albicilla) nestlings. The nestlings were sampled at two locations, Smøla and Steigen, in 2015 and 2016. The age of the nestlings was recorded (range: 44 – 87 days old) and stable carbon and nitrogen isotopes (δ13C and δ15N) were applied as dietary proxies for carbon source and trophic position, respectively. In total, 14 polychlorinated biphenyls (PCBs, range: 0.82 – 59.05 ng/mL), 7 organochlorinated pesticides (OCPs, range: 0.89 – 52.19 ng/mL), 5 polybrominated diphenyl ethers (PBDEs, range: 0.03 – 2.64 ng/mL) and 8 perfluoroalkyl substances (PFASs, range: 4.58 – 52.94 ng/mL) were quantified in plasma samples from each location and year. The OHC concentrations, age and dietary proxies displayed temporal and spatial variations. The age of the nestlings was indicated as the most important predictor for OHC variation as the models displayed significantly decreasing plasma concentrations of PCBs, OCPs, and PBDEs with increasing age, while concentrations of PFASs were significantly increasing with age. Together with age, the variations in PCB, OCP and PBDE concentrations were also explained by δ13C and indicated decreasing concentrations with a more marine diet. Our findings emphasise age and diet as important factors to consider when investigating variations in plasma OHC concentrations in nestlings. © 2018 Elsevier Ltd [less ▲]

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See detailChanges in stable isotope compositions during fasting in phocid seals
Habran, Sarah ULiege; Damseaux, France ULiege; Pomeroy, Paddy et al

in Rapid Communications in Mass Spectrometry (2019)

RATIONALE: The grey seal, Halichoerus grypus (GS), and the northern elephant seal, Mirounga angustirostris (NES), come ashore for reproduction. This period involves intense physiological processes such as ... [more ▼]

RATIONALE: The grey seal, Halichoerus grypus (GS), and the northern elephant seal, Mirounga angustirostris (NES), come ashore for reproduction. This period involves intense physiological processes such as lactation in females and a developmental post-weaning fast in juveniles. Previous studies have shown δ13C and δ15N values are affected by starvation, but the precise effects of fasting associated to lactation and post-weaning fast in seals remains poorly understood. METHODS: To examine the effect of lactation and post-weaning fast on stable isotopes in GS and NES, blood and hair were sampled from twenty-one GS mother-pup pairs on the Isle of May and on twenty-two weaned NES pups at Año Nuevo State Reserve during their respective breeding seasons. Milk samples were also collected from GS mothers. Stable isotope measurements were performed with an isotope ratio mass spectrometer coupled to an N-C elemental analyser. RESULTS: Changes in stable isotope ratios in blood components during fasting were similar and weak between GS and NES mothers especially in blood cells (GS: Δ15N = 0.05‰, Δ13C = 0.02‰; NES: Δ15N = 0.1‰, Δ13C = 0.1‰). GS showed a 15N discrimination factor between maternal and pup blood cells and milk, but not for 13C. The strongest relationship between the isotopic compositions of the mother and the pup was observed in the blood cells. CONCLUSIONS: Isotopic consequences of lactation, fasting, and growth seem limited in NES and GS, especially in medium-term integrator tissues of feeding activity such as blood cells. Stable isotope ratios in the blood of pups and mothers are correlated. We observed a subtle mother-to-pup fractionation factor. Our results suggest that pup blood cells are mostly relevant for exploring the ecology of female seals. [less ▲]

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See detailStabilizing effects of seagrass meadows on coastal water benthic food webs
Jankowska, Emilia; Michel, Loïc ULiege; Lepoint, Gilles ULiege et al

in Journal of Experimental Marine Biology and Ecology (2019), 510

Seagrass meadows ecosystem engineering effects are correlated to their density (which is in turn linked to seasonal cycles) and often cannot be perceived below a given threshold level of engineer density ... [more ▼]

Seagrass meadows ecosystem engineering effects are correlated to their density (which is in turn linked to seasonal cycles) and often cannot be perceived below a given threshold level of engineer density. The density and biomass of seagrass meadows (Z. marina) together with associated macrophytes undergo substantial seasonal changes, with clear declines in winter. The present study aims to test whether the seasonal changes in the density of recovering seagrass meadows affect the benthic food webs of the southern Baltic Sea (Puck Bay). It includes meiofauna, macrofauna and fish of vegetated and unvegetated habitats in summer and winter seasons. Two levels of organization have been tested – species-specific diet preferences using stable isotopes (δ13C, δ15N) in Bayesian mixing models (MixSIAR) and the community-scale food web characteristics by means of isotopic niches (SIBER). Between-habitat differences were observed for grazers, as a greater food source diversity in species from vegetated habitats was noted in both seasons. Larger between-habitat differences in winter were documented for suspension/detritus feeders. The community-wide approach showed that the differences between the habitats were greater in winter than in summer (as indicated by the lower overlap of the respective isotope niches). Overall, the presence of seagrass meadows increased ecological stability (in terms of the range of food sources utilized by consumers) in the faunal assemblage, while invertebrates from unvegetated areas shifted their diet to cope with winter conditions. Therefore, as a more complex system, not sensitive to seasonal changes, Z. marina meadows create a stable habitat with high resilience potential. [less ▲]

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See detailRefugia and ecosystem tolerance in the Southern Ocean
Schön, Isa; Christiansen, Henrik; Danis, Bruno et al

Poster (2018, December 15)

Confronted with fast-paced environmental changes, biota in Antarctic ecosystems are strongly challenged and face three possible outcomes: adaptation, migration or extinction. Past glaciation periods have ... [more ▼]

Confronted with fast-paced environmental changes, biota in Antarctic ecosystems are strongly challenged and face three possible outcomes: adaptation, migration or extinction. Past glaciation periods have already forced marine zoobenthos of the Southern Ocean (SO) into refugia, followed by recolonization when the ice retreated. The collaborative Belgian BRAIN project RECTO, “Refugia and ecosystem tolerance in the Southern Ocean”, will strive at understanding how such past events have driven diversification and adaptation in different animal groups and how these can be applied as proxies to understand the contemporary situation and predict future scenarios. With molecular approaches, RECTO will reconstruct population histories and spatio-temporal features of Pleistocene refugia. The RECTO target taxa include birds, fish, sea stars, bivalves, amphipods, and ostracods. For all RECTO target taxa, the following molecular data will be obtained: (1) mitochondrial COI barcodes, (2) ddRAD data, and (3) mitochondrial genomes. Mitochondrial genomes will be obtained by genome skimming, and long range PCRs. Mitogenomes can improve the unravelling of phylogeographic relationships and dating of evolutionary events and, through comparisons with non-Antarctic taxa, allow to detect cold adaptations. In fish and amphipods, RECTO will also study in a novel phylogenetic framework how morphological diversification and trophic adaptability (estimated by stable isotope data) are interacting with each other and whether ecotypes of selected species have faster modes of evolution. Geographic models on future species and trait distributions based on physiological and energy limits and present and future climate data will be refined and integrated with individual based models for the SO. Finally, scenarios of future dispersal abilities and possible habitat shifts of the RECTO target groups will be developed to infer how the RECTO target species will respond to future climate change. [less ▲]

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See detailRefugia and ecosystem tolerance in the Southern Ocean
Schön, Isa; Christiansen, Henrik; De Ridder, Chantal et al

Poster (2018, December 15)

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See detailEcological diversification, recent evolution and speciation of Amphipoda in the polar regions: the case study of Eusirus genus
Salabao, Louraine ULiege; Lepoint, Gilles ULiege; Frederich, Bruno ULiege et al

Poster (2018, December 15)

Because of their long history, the polar regions and especially Antarctica are natural laboratories for evolutionary research. The diverse and specialized polar fauna has evolved during millions of years ... [more ▼]

Because of their long history, the polar regions and especially Antarctica are natural laboratories for evolutionary research. The diverse and specialized polar fauna has evolved during millions of years, and has survived past environmental changes including the glaciations. Given that certain parts of the polar regions are among the fastest warming regions on this planet, knowledge on how these organisms managed to survive climate changes in the past can help us to extrapolate to the future. Here, Eusirus amphipods (crustaceans) are chosen as model organisms because they occur on both poles, are very diverse and live in different habitats. Our knowledge on their ecology and biogeography is still very limited although they are an important component of the marine fauna. From the same amphipod specimens, genetic data, morphological data and ecological data (general ecology, trophic ecology) will be acquired. The evolutionary history of Eusirus amphipods will be reconstructed through time with phylogenetic and population genetic methods, and the obtained phylogenies will be used to map morphological and ecological diversity. This will ultimately reveal which evolutionary processes led to the current diversity of Eusirus amphipods, and if speciation events were constant through time or occurred in bursts. This kind of analyses will also test if there has been convergent evolution of Eusirus amphipods in the two polar regions. [less ▲]

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See detailZOOLOGY 2018 _ Zoology in the Anthropocene - Abstract Book
Decaestecker, Ellen; Lepoint, Gilles ULiege

Book published by Royal Belgian Zoological Society (2018)

Abstract book of the ZOOLOGY 2018 meeting (13-15 December 2018, @Zoo, Antwerpen). In addition, a workshop on basic skills for young scientists (networking, paper writing, reviewing, presentation feedback ... [more ▼]

Abstract book of the ZOOLOGY 2018 meeting (13-15 December 2018, @Zoo, Antwerpen). In addition, a workshop on basic skills for young scientists (networking, paper writing, reviewing, presentation feedback) will be organized on the 13th of December by the RBZS Young Zoologists Group. The general theme of the ZOOLOGY 2018 meeting is “Zoology in the Anthropocene” with two special sessions: 1. “Crossing borders: why and how biologists and climatologists must speak together”; 2. “How animals face global change: plasticity, resilience, adaptation”. As usual, the congress will also welcome all contributions from the field of Zoology, from the molecule to the biosphere. Thematic sessions will be organized depending on received abstracts. All zoologists, at any stage of their career, are very welcome to participate actively during the whole meeting, and young scientists are particularly encouraged to contribute (especially to the Young Zoologist workshop). Confirmed keynote speakers are Hilde Eggermont (Belgian Biodiversity Platform), Eelke Jongejans (Nijmegen) and Alexander Wilting. The floor will also be given to the Kets prize and KCZS winners. [less ▲]

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See detailEchinometra mathaei and its ectocommensal shrimps: the role of sea urchin spinochrome pigments in the symbiotic association
Brasseur, Lola; Caulier, Guillaume; Lepoint, Gilles ULiege et al

in Scientific Reports (2018), 8(17540),

Tuleariocaris holthuisi and Arete indicus are two ectocommensal shrimps closely associated with the tropical sea urchin Echinometra mathaei. This study provides a comparison of these two E. mathaei ... [more ▼]

Tuleariocaris holthuisi and Arete indicus are two ectocommensal shrimps closely associated with the tropical sea urchin Echinometra mathaei. This study provides a comparison of these two E. mathaei symbiotic crustaceans and particularly focuses on the relationship between T. holthuisi and its host’s pigments (i.e. spinochromes), and its dependency on its host. While all the analyses underline a close association between A. indicus and E. mathaei, they reveal a particularly close interaction between T. holthuisi and its host. Chemical analyses reveal that these shrimps present the same spinochrome composition as E. mathaei, and have similar colouration, allowing camouflage. Isotopic composition and pigment loss after host separation suggest that these pigments are certainly assimilated upon feeding on the urchin. Moreover, symbiont isolation experiments demonstrate the high dependency of T. holthuisi on its host and the importance of the host’s pigments on their survival capacity. Finally, some host recognition mechanisms are investigated for T. holthuisi and show the probable implication of spinochromes in host selection, through chemical recognition. Hence, all the results suggest the essential roles of spinochromes for T. holthuisi, which, in turn, suggests the potential implication of these pigments in the shrimps’ metabolism. [less ▲]

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See detailGenetic diversity mirrors trophic ecology in coral reef fish feeding guilds
Gajdzik, Laura; Bernardi, Giacomo; Lepoint, Gilles ULiege et al

in Molecular Ecology (2018), 27

Genetic diversity is essential for species persistence because it provides the raw material for evolution. For marine organisms, short pelagic larval duration (PLD) and small population size are ... [more ▼]

Genetic diversity is essential for species persistence because it provides the raw material for evolution. For marine organisms, short pelagic larval duration (PLD) and small population size are characteristics generally assumed to associate with low genetic diversity. The ecological diversity of organisms may also affect genetic diversity, with an expected corollary that more restricted habitat and dietary requirements could lead to a reduced genetic diversity because of pronounced genetic structuring. Here, we tested whether groups of species with narrower trophic niches displayed lower genetic diversity than those with broader niches. In order to test those predictions, we used different trophic guilds (i.e. groups of species having similar trophic habits) of coral reef damselfishes in Moorea (French Polynesia) for which we determined their genetic diversity using Restriction site−associated DNA sequencing (RADseq) and their trophic ecology with stomach contents and stable isotope data. We found that pelagic feeders, i.e. the guild picking zooplankton in the water column, exhibited the lowest genetic diversity despite having the longest PLD and the largest population size. This guild had also the lowest variation in habitat characteristics and dietary composition compared to benthic feeders (i.e. those mainly grazing on algae) and the intermediate group (i.e. those feeding on zooplankton, filamentous algae and small benthic invertebrates). Our findings highlight the association between trophic ecology and genetic diversity that should be more commonly investigated in population genetics. [less ▲]

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