Suchergebnisse

ABSTRACT Reconstruction of silica cycling in the oceans is key to a thorough understanding of past climates because of the inherent links between the biogeochemistry of silicifiers and sequestration of organic carbon. Diatoms are one of the most important phytoplankton groups in determining export production from surface waters, and rely largely on upwelling deeper waters as a source of dissolved silicon, an essential nutrient for their growth. Quantification of changes in deep water dissolved silicon concentrations in the past allows a more robust understanding of changes in surface nutrient supply and whole-ocean silicon cycling, but cannot be achieved using surface-derived geochemical archives. In the last few years, there has been increasing focus on the use of geochemical archives in siliceous skeletal elements, or spicules, from seafloor-dwelling sponges to fill this gap. The stable silicon isotopic composition of spicules has been shown to be a function of ambient dissolved silicon, providing a potential archive for past changes in bottom water nutrients. However, biomineralisation processes impact silicon isotope fractionation and silica formed by atypical processes (derived from carnivorous sponges, hypersilicified spicules, and giant basal spicules) result in anomalous geochemical signatures. Furthermore, there is considerable scatter in the calibration between spicule silicon isotopes and dissolved silicon in seawater, even when the atypical groups have been removed. Here, we explore this variability further, by examining aggregation and assemblage-level differences in isotopic fractionation, using silicon isotopic measurements of specimens from two monospecific sponge groups (Pheronema carpenteri and Vazella pourtalesi), and one mixed-species population (genus Geodia) from the North Atlantic. Our new data reveal that variability within the monospecific aggregations is less than mixed-species assemblage, pointing towards a genetic control in isotopic fractionation. However, there is still variability ...

ABSTRACT Water masses are bodies of water with distinctive physical and biogeochemical properties. They impart vertical structure to the deep ocean, participate in circulation, and can be traced over great distances, potentially influencing the distributions of deep-sea fauna. The classic potential temperature-salinity (θ-s) diagram was used to investigate deep-sea sponge (demosponge genus Geodia) association with water masses over the North Atlantic Ocean and Nordic Seas. A novel analysis was conducted, based on sampling the curvature of climatological mean θ-s curves at sponge locations. Sponges were particularly associated with turning points in the θ-s curves, indicative of intermediate and deep water masses. Arctic geodiid species (G. hentscheli and G. parva) were associated with Arctic intermediate and deep waters in the Nordic Seas, and with dense overflows into the northern North Atlantic. Boreal species (G. atlantica, G. barretti, G. macandrewii, and G. phlegraei) were associated with upper and intermediate water masses in the Northeast Atlantic and with upper, Atlantic-derived waters in the Nordic Seas. Taken together with distributional patterns, a link with thermohaline currents was also inferred. We conclude that water masses and major current pathways structure the distribution of a key deep-sea benthic faunal group on an ocean basin scale. This is most likely because of a combination of the physical constraints they place on the dispersal of early life-history stages, ecophysiological adaptation (evolved tolerances) to specific water masses, and the benefits to filter-feeders of certain phenomena linked to water column structure (e.g. nepheloid layers, internal waves/tides, density-driven currents). ; ACKNOWLEDGEMENTS This article is dedicated to the memory of our friend and esteemed colleague Prof. Hans Tore Rapp. We are grateful to Joana Xavier (CIIMAR, Portugal), Pedro Ribeiro, Mari Heggernes Eilertsen, and Francisca Carvalho (all at the University of Bergen, UiB) for discussions on sponge ...

Marine sponges are ancient metazoans that are populated by distinct and highly diverse microbial communities. In order to obtain deeper insights into the functional gene repertoire of the Mediterranean sponge Aplysina aerophoba, we combined Illumina short-read and PacBio long-read sequencing followed by un-targeted metagenomic binning. We identified a total of 37 high-quality bins representing 11 bacterial phyla and two candidate phyla. Statistical comparison of symbiont genomes with selected reference genomes revealed a significant enrichment of genes related to bacterial defense (restriction-modification systems, toxin-antitoxin systems) as well as genes involved in host colonization and extracellular matrix utilization in sponge symbionts. A within-symbionts genome comparison revealed a nutritional specialization of at least two symbiont guilds, where one appears to metabolize carnitine and the other sulfated polysaccharides, both of which are abundant molecules in the sponge extracellular matrix. A third guild of symbionts may be viewed as nutritional generalists that perform largely the same metabolic pathways but lack such extraordinary numbers of the relevant genes. This study characterizes the genomic repertoire of sponge symbionts at an unprecedented resolution and it provides greater insights into the molecular mechanisms underlying microbial-sponge symbiosis. ; This project was funded by Grant Number CSP1291 of the DOE Joint Genome Institute, the European Commission within its FP7 Program, under the thematic area KBBE.2012.3.2.-01 with Grant Number 311932 ('SeaBio-Tech'), and by the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 679849 ('SponGES'). BMS was supported by a grant of the German Excellence Initiative to the Graduate School of Life Sciences, University of Würzburg. We thank Monika Bright (University of Vienna) and the Marine Biology Station Piran for support during sampling, Tanja Woyke (DOE Walnut Creek, CA, USA) for helpful discussions on ...

The Fact sheet describes the goals and Objectives of Work Package 8 of the SponGES project, which is to advance the science-management-policy interface and develop tools for improved resource management and understanding of deep-sea sponge ecosystems from regional to international levels across the Atlantic.

The fourth of a six-pieces collection of info-sheets about deep-sea sponges and their habitats, released by SponGES partner FAO.

The sixth of a six-pieces collection of info-sheets about deep-sea sponges and their habitats, released by SponGES partner FAO.

This SponGES policy brief provides a list of ecosystem features of deep-sea sponges covering five different domains: distribution, biodiversity, genetic diversity, nutrient and element fluxes, and response to threats and impacts. It also presents the results of a questionnaire that was administered to sponge experts within the SponGES project, to gain further knowledge and understanding on the overall ecological value of deep-sea sponges and possible consequences of their damage/destruction.

The third of a six-pieces collection of info-sheets about deep-sea sponges and their habitats, released by SponGES partner FAO.

The fifth of a six-pieces collection of info-sheets about deep-sea sponges and their habitats, released by SponGES partner FAO.

ABSTRACT. Sponges (phylum Porifera) are benthic filter feeding animals that play an important role in nutrient cycling and habitat provision in the deep sea. Sponges collected between 2010 and 2014 during annual multispecies trawl surveys conducted by Fisheries and Oceans Canada in Baffin Bay, Davis Strait and portions of Hudson Strait were taxonomically examined. In total ~2500 specimens were identified, comprising ~100 known sponge taxa. Sponges from the order Poecilosclerida comprised nearly half of the identified species. Sponges from the poescilosclerid families Coelosphaeridae, Crellidae, Dendoricellidae, Myxillidae and Tedaniidae are described in previous reports. This report adds descriptions of eight sponge species from three poescilosclerid families: Microcionidae, Acarnidae and Esperiopsidae (class Demospongiae, subclass Heteroscleromorpha, order Poecilosclerida). Described species include Artemisina lundbecki, Artemisina arcigera, and Clathria (Clathria) barleei from the family Microcionidae, Iophon piceum and Iophon koltuni from the family Acarnidae, and Esperiopsis villosa, Esperiopsis sp. 1, and Semisuberites cf. cribrosa from the family Esperiopsidae. Descriptions include physical description of the sponges, descriptions and dimensions of their spicules, and taxonomic discussion. RÉSUMÉ. Les éponges (phylum Porifera) sont des animaux filtreurs benthiques qui jouent un rôle important dans le cycle des éléments nutritifs et qui augmentent la disponibilité d'habitats benthiques en eaux profondes. Les éponges collectées au cours des relevés plurispécifiques annuels au chalut effectués entre 2010 et 2014 par Pêches et Océans Canada dans la baie de Baffin, le détroit de Davis et certaines portions du détroit d'Hudson ont été examinées sur le plan taxonomique. Au total, environ 2500 spécimens ont été identifiés, appartenant à ~100 taxons d'éponges connus. Presque la moitié des espèces recensées appartiennent à l'ordre Poecilosclerida. Parmi elles, les éponges des familles Coelosphaeridae, Crellidae, ...

This SponGES project policy brief shows how deep-sea sponges represent a source of chemicals with potential pharmaceutical and industrial applications, and it discusses the knowledge gaps and challenges in unlocking their biotechnological potential.

Emerald Basin on the Scotian Shelf off Nova Scotia, Canada, is home to a globally unique population of the glass sponge Vazella pourtalesi. Through the analysis of both in situ photographs and trawl catch data from annual multispecies bottom-trawl surveys, we examined community composition, species density, and abundance of epibenthos and fish associated with V. pourtalesi compared to locations without this sponge. Using generalized linear models and analysis of similarities, the importance of V. pourtalesi in enhancing species density and abundance of the associated epibenthic community was assessed against that of the hard substrate on which it settles. Our results indicated that the megafaunal assemblage associated with V. pourtalesi was significantly different in composition and higher in species density and abundance compared to locations without V. pourtalesi. Analysis of similarity of trawl catch data indicated that fish communities associated with the sponge grounds are significantly different from those without V. pourtalesi, although no species were found exclusively on the sponge grounds. Our study provides further evidence of the role played by sponge grounds in shaping community structure and biodiversity of associated deep-sea epibenthic and fish communities. The mechanism for biodiversity enhancement within the sponge grounds formed by V. pourtalesi is likely the combined effect of both the sponge itself and its attachment substrate, which together comprise the habitat of the sponge grounds. We also discuss the role of habitat provision between the mixed-species tetractinellid sponges of the Flemish Cap and the monospecific glass sponge grounds of Emerald Basin. ; ACKNOWLEDGEMENTS. This work was funded in part through the SponGES—Deep-sea Sponge Grounds Ecosystems of the North Atlantic: an integrated approach towards their preservation and sustainable exploitation, under H2020 - the EU Framework Programme for Research and Innovation (Grant Agreement no. 679849) where Fisheries and Oceans Canada ...

This fact sheet provides information on the Objectives and activities of Work Package 6 of the SponGES project: Threats and impacts to sponge grounds. Considering diverse anthropogenic stressors acting on the deep sea and the vulnerability of deep-sea sponges to human disturbance, it is urgent to understand the full scale of human impacts on these ecosystems, and how they interact with each other. Such information is essential to respond to international regulations such as the UNGA Resolution 61/105 for the protection of vulnerable marine ecosystems from destructive fishing practices and for identifying indicators of Good Environmental Status for seafloor integrity of the Marine Strategy Framework Directive.

ABSTRACT Sponges are ubiquitous components of various deep-sea habitats, including cold water coral reefs and deep-sea sponge grounds. Despite being surrounded by oligotrophic waters, these ecosystems are known to be hotspots of biodiversity and carbon cycling. To assess the role of sponges in the carbon cycling of deep-sea ecosystems, we studied the energy budgets of six dominant deep-sea sponges (the hexactinellid species Vazella pourtalesi, and demosponge species Geodia barretti, Geodia atlantica, Craniella zetlandica, Hymedesmia paupertas and Acantheurypon spinispinosum) in an ex situ aquarium setup. Additionally, we determined morphological metrics for all species (volume, dry weight (DW), wet weight (WW), carbon (C) content, and ash-free dry weight (AFDW)) and provide species-specific conversion factors. Oxygen (O2) removal rates averaged 3.3 ± 2.8 µmol O2 DWsponge h−1 (all values mean ± SD), live particulate (bacterial and phytoplankton) organic carbon (LPOC) removal rates averaged 0.30 ± 0.39 µmol C DWsponge h−1 and dissolved organic carbon (DOC) removal rates averaged 18.70 ± 25.02 µmol C DWsponge h−1. Carbon mass balances were calculated for four species (V. pourtalesi, G. barretti, G. atlantica and H. paupertas) and revealed that the sponges acquired 1.3–6.6 times the amount of carbon needed to sustain their minimal respiratory demands. These results indicate that irrespective of taxonomic class, growth form, and abundance of microbial symbionts, DOC is responsible for over 90 % of the total net organic carbon removal of deep-sea sponges and allows them to sustain in otherwise food-limited environments on the ocean floor. ; ACKNOWLEDGEMENTS We thank all our collaborators at the EU Horizon 2020 SponGES project; Dr. Ellen Kenchington at the Bedford Institute of Oceanography (BIO), Nova Scotia, Canada, and the Department of Biological Sciences at the University of Bergen, Norway, for the use of facilities and equipment. Many thanks to the ROV crews of both the ÆGIR 6000 in Norway and the Deep Sea Systems ...

ABSTRACT Most animals, including sponges (Porifera), have species‐specific microbiomes. Which genetic or environmental factors play major roles structuring the microbial community at the intraspecific level in sponges is, however, largely unknown. In this study, we tested whether geographic location or genetic structure of conspecific sponges influences their microbial assembly. For that, we used three sponge species with different rates of gene flow, and collected samples along their entire distribution range (two from the Mediterranean and one from the Southern Ocean) yielding a total of 393 samples. These three sponge species have been previously analysed by microsatellites or single nucleotide polymorphisms, and here we investigate their microbiomes by amplicon sequencing of the microbial 16S rRNA gene. The sponge Petrosia ficiformis, with highly isolated populations (low gene flow), showed a stronger influence of the host genetic distance on the microbial composition than the spatial distance. Host‐specificity was therefore detected at the genotypic level, with individuals belonging to the same host genetic cluster harbouring more similar microbiomes than distant ones. On the contrary, the microbiome of Ircinia fasciculata and Dendrilla antarctica ‐ both with weak population structure (high gene flow) ‐ seemed influenced by location rather than by host genetic distance. Our results suggest that in sponge species with high population structure, the host genetic cluster influence the microbial community more than the geographic location. ; ACKNOWLEDGEMENTS This project has received funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Skłodowska‐Curie Individual Fellowships Grant Agreement No. 796011 ('DeepSym'), and Grant Agreement No. 679849 ('SponGES'). We thank the team around Andre Franke at the Institute of Clinical Molecular Biology, Kiel, for sequencing support. We also want to thank Shaun Nielsen for support and guidance through data analysis. Finally, we ...