Deep-sea Research Part I-oceanographic Research Papers, Oct 1, 2012
ABSTRACT Knowledge of the reproductive life-history of deep-water corals is important for assessi... more ABSTRACT Knowledge of the reproductive life-history of deep-water corals is important for assessing their vulnerability to anthropogenic impacts. Yet, the reproductive biology of many deep-water corals, especially members of the subclass Octocorallia, has not been examined. We used histological techniques to describe the reproductive biology of the deep-water gorgonian coral Acanella arbuscula from the northwest Atlantic. All colonies examined were gonochoric, and no embryos or planula larvae were observed in the polyps. Mean polyp-level fecundity (females: 21.0 7 17.5 oocytes polyp À 1 , and males: 13.9 7 13.5 sperm sacs polyp À 1) is high compared to other deep-water gorgonians, and polyps closer to the branch tips had the highest fecundities in both females and males. The presence of large oocytes (maximum diameter 717.8 mm) suggests that A. arbuscula produces lecithotrophic larvae. Despite the potentially high fecundity and small size at first reproduction, the paucity of information on dispersal and recruitment, combined with its longevity, vulnerability to bottom fishing gear, and ecological role as a structure-forming species, still warrants the classification of A. arbuscula as a vulnerable marine ecosystem indicator.
Anthropogenic pressures on marine ecosystems and organisms are steadily increasing. Whether and t... more Anthropogenic pressures on marine ecosystems and organisms are steadily increasing. Whether and to which extent these pressures influence marine biodiversity is only starting to unveil. Establishment of adequate conservation areas represents a challenging but crucial task in the conservation of genetic diversity and biological variability. Using 16S rRNA gene amplicon sequencing, we analysed the microbial community structure of 32 individuals of the habitat-forming glass sponge Vazella pourtalesii, as well as reference seawater, sediment, and biofilm samples. We assessed how two anthropogenic impacts, i.e. habitat destruction by trawling and artificial substrate provision (moorings made of composite plastic), correspond with in situ V. pourtalesii microbiome variability. In addition, we evaluated the role of two bottom fishery closures in preserving sponge-associated microbial diversity on the Scotian Shelf, Canada.
Biogeochemical cycling of silicon (Si), largely affected by biological drivers, is pivotal to the... more Biogeochemical cycling of silicon (Si), largely affected by biological drivers, is pivotal to the ecological functioning of the ocean. Most knowledge regarding biological utilization of Si derives from research on phototrophic organisms circumscribed to the photic ocean (i.e., diatoms). Utilization of Si in the aphotic ocean, where heterotrophic silicifiers become relevant Si users, remains poorly investigated. Here we quantify the flux rates and stocks characterizing Si cycling across dense aggregations of the hexactinellid sponge Vazella pourtalesii established in the aphotic zone of the central Scotian Shelf, Nova Scotia, Canada. Although individual rates of silicic acid consumption were low compared to other sponge species and diatoms, the large abundance of individuals (6.5 million) over the extension of these sponge grounds (2105 km2) leads to massive annual silicic acid consumption, invested in producing their siliceous skeletons of biogenic silica. This sponge activity accumulates large biogenic silica stocks both in the living population and in the sediments. Skeletal pieces in sediment revealed that a good portion of biogenic silica deposited to the bottom after sponge death recycles as silicic acid before being permanently buried. This biogenic silica–silicic acid turnover, facilitated by an unconventional silicification pattern that favors delamination and dissolution of V. pourtalesii spicules, causes silicic acid enrichment at oceanographic dimensions in the bottom water of the central Scotian Shelf. Silicic acid efflux from the bottom sustains a feedback mechanism that fulfills sponge needs for silicic acid and facilitates the persistence of sponge aggregations in the long term.
Deep-sea sponges are important contributors to carbon and nitrogen cycling due to their large fil... more Deep-sea sponges are important contributors to carbon and nitrogen cycling due to their large filtration capacity. Species of the suborder Astrophorina form dense sponge grounds in the North Atlantic, where they serve as prey for spongivores, but also have non-trophic interactions with commensal epi- and endobionts. At the Flemish Cap (NW Atlantic) Astrophorina sponges are present in four previously described deep-sea epifaunal assemblages: the deep-sea coral assemblage, the lower slope assemblages 1 and 2, and the deep-sea sponge assemblage. To investigate their role in trophic and non-trophic interactions at the Flemish Cap, we developed trophic-/ non-trophic interaction web models for each of the four faunal assemblages using the published literature. By excluding the sponges from the models, we estimated how many trophic, facultative and obligatory non-trophic links would be lost, and how this removal affected food-web properties (number of compartments, links, link density, and...
A new Tedania species (Porifera) was collect using remotely operated vehicles during the Canadian... more A new Tedania species (Porifera) was collect using remotely operated vehicles during the Canadian mission HUD2010-029 and the British RRS Discovery Cruise DY081, on the Orphan Seamount near the Orphan Knoll, northwest Atlantic, between 2999.88 and 3450.4 m depth. Orphan Knoll is an isolated, drowned continental fragment 550 km northeast Newfoundland in the Labrador Sea. This region is biologically rich and complex and in 2007, the regional fisheries management organization operating in the area regulated that no vessel shall engage in bottom-contact fishing activities until reviewed in 2020 with a review slated at the end of this year. Members of the genus Tedania are uncommon in the temperate northern hemisphere with only six species known previously: Tedania (Tedania) anhelans; Tedania (Tedania) pilarriosae; Tedania (Tedania) suctoria; Tedania (Tedania) urgorrii; Tedania (Tedaniopsis) gurjanovae; and Tedania (Tedaniopsis) phacellina. The particular features of the new sponge we de...
Marine sponges (phylum Porifera) are leading organisms for the discovery of bioactive compounds f... more Marine sponges (phylum Porifera) are leading organisms for the discovery of bioactive compounds from nature. Their often rich and species-specific microbiota is hypothesised to be producing many of these compounds. Yet, environmental influences on the sponge-associated microbiota and bioactive compound production remain elusive. Here, we investigated the changes of microbiota and metabolomes in sponges along a depth range of 1232 m. Using 16S rRNA gene amplicon sequencing and untargeted metabolomics, we assessed prokaryotic and chemical diversities in three deep-sea sponge species:Geodia barretti,Stryphnus fortis, andWeberella bursa. Both prokaryotic communities and metabolome varied significantly with depth, which we hypothesized to be the effect of different water masses. Up to 35.5% of microbial ASVs (amplicon sequence variants) showed significant changes with depth while phylum-level composition of host microbiome remained unchanged. The metabolome varied with depth, with relati...
We report the first records of the new species Tedania (Tedaniopsis) rappi (Demospongiae, Poecilo... more We report the first records of the new species Tedania (Tedaniopsis) rappi (Demospongiae, Poecilosclerida, Tedaniidae) from the Orphan Seamount, between 2999.88 and 3449.629 m in depth.
Vazella pourtalesi presence and absence data were obtained from several different sources: DFO... more Vazella pourtalesi presence and absence data were obtained from several different sources: DFO's multispecies trawl survey conducted in the Maritimes Region between 2007 to 2017 (presences and absences), DFO optical (in-house camera/video and remotely operated vehicle) benthic surveys conducted between 2001 and 2017 (presences only), and commercial bycatch records from the Fisheries Observer Program (FOP) from 1997 to 2007, and 2010 to 2015 (presences only). The DFO multispecies trawl survey is stratified random (by depth) and conducted using primarily Western IIA trawl gear. The average distance of these tows is ~ 3.17 km. Absence records were created from null (zero) catches that occurred in the same surveys. Commercial bycatch data between 1997 to 2007 from the Fisheries Observer Program was further post-processed and validated for accuracy, while the data from 2010 to 2015 was extracted directly from the Maritimes Fishery Science Database managed by DFO. Commercial trawls ar...
Models of probability of occurrence and predicted biomass distribution have been created using ra... more Models of probability of occurrence and predicted biomass distribution have been created using random forest (RF) machine learning techniques for different invertebrate taxa in the Gulf of St. Lawrence. Response data were derived from by-catch data collected from DFO research vessel trawl surveys following a stratified random design based on depth and geographic region. Predictors were drawn from 78 environmental data layers. Occurrence models performed very well for sea pens and stalked tunicates and better than those for soft corals and sponges, with cross-validated AUC (area under the receiver operating characteristic curve) values ranging from 0.71 to 0.91. For the models based on biomass, soft corals and sea pens had the highest R2 values (0.42 and 0.37, respectively) in the southern Gulf of St. Lawrence and stalked tunicates and sea pens in the north (0.41 and 0.27, respectively). Sponges had R2 values less than 0.1 in both areas indicating poor model performance. Biomass models from RF were compared with Generalized Additive Models (GAM). In most of the cases RF and GAM models provided similar results and were both good options, although the fewer assumptions required for RF makes this method more convenient. These results could be used to identify the potential distribution of some vulnerable marine ecosystems indicator taxa and help to refine the borders of the significant benthic area polygons defining significant concentrations of these taxa as identified through the kernel density analyses. In particular these models can be used to extrapolate to areas not covered by the research vessel surveys.
Deep-sea Research Part I-oceanographic Research Papers, Oct 1, 2012
ABSTRACT Knowledge of the reproductive life-history of deep-water corals is important for assessi... more ABSTRACT Knowledge of the reproductive life-history of deep-water corals is important for assessing their vulnerability to anthropogenic impacts. Yet, the reproductive biology of many deep-water corals, especially members of the subclass Octocorallia, has not been examined. We used histological techniques to describe the reproductive biology of the deep-water gorgonian coral Acanella arbuscula from the northwest Atlantic. All colonies examined were gonochoric, and no embryos or planula larvae were observed in the polyps. Mean polyp-level fecundity (females: 21.0 7 17.5 oocytes polyp À 1 , and males: 13.9 7 13.5 sperm sacs polyp À 1) is high compared to other deep-water gorgonians, and polyps closer to the branch tips had the highest fecundities in both females and males. The presence of large oocytes (maximum diameter 717.8 mm) suggests that A. arbuscula produces lecithotrophic larvae. Despite the potentially high fecundity and small size at first reproduction, the paucity of information on dispersal and recruitment, combined with its longevity, vulnerability to bottom fishing gear, and ecological role as a structure-forming species, still warrants the classification of A. arbuscula as a vulnerable marine ecosystem indicator.
Anthropogenic pressures on marine ecosystems and organisms are steadily increasing. Whether and t... more Anthropogenic pressures on marine ecosystems and organisms are steadily increasing. Whether and to which extent these pressures influence marine biodiversity is only starting to unveil. Establishment of adequate conservation areas represents a challenging but crucial task in the conservation of genetic diversity and biological variability. Using 16S rRNA gene amplicon sequencing, we analysed the microbial community structure of 32 individuals of the habitat-forming glass sponge Vazella pourtalesii, as well as reference seawater, sediment, and biofilm samples. We assessed how two anthropogenic impacts, i.e. habitat destruction by trawling and artificial substrate provision (moorings made of composite plastic), correspond with in situ V. pourtalesii microbiome variability. In addition, we evaluated the role of two bottom fishery closures in preserving sponge-associated microbial diversity on the Scotian Shelf, Canada.
Biogeochemical cycling of silicon (Si), largely affected by biological drivers, is pivotal to the... more Biogeochemical cycling of silicon (Si), largely affected by biological drivers, is pivotal to the ecological functioning of the ocean. Most knowledge regarding biological utilization of Si derives from research on phototrophic organisms circumscribed to the photic ocean (i.e., diatoms). Utilization of Si in the aphotic ocean, where heterotrophic silicifiers become relevant Si users, remains poorly investigated. Here we quantify the flux rates and stocks characterizing Si cycling across dense aggregations of the hexactinellid sponge Vazella pourtalesii established in the aphotic zone of the central Scotian Shelf, Nova Scotia, Canada. Although individual rates of silicic acid consumption were low compared to other sponge species and diatoms, the large abundance of individuals (6.5 million) over the extension of these sponge grounds (2105 km2) leads to massive annual silicic acid consumption, invested in producing their siliceous skeletons of biogenic silica. This sponge activity accumulates large biogenic silica stocks both in the living population and in the sediments. Skeletal pieces in sediment revealed that a good portion of biogenic silica deposited to the bottom after sponge death recycles as silicic acid before being permanently buried. This biogenic silica–silicic acid turnover, facilitated by an unconventional silicification pattern that favors delamination and dissolution of V. pourtalesii spicules, causes silicic acid enrichment at oceanographic dimensions in the bottom water of the central Scotian Shelf. Silicic acid efflux from the bottom sustains a feedback mechanism that fulfills sponge needs for silicic acid and facilitates the persistence of sponge aggregations in the long term.
Deep-sea sponges are important contributors to carbon and nitrogen cycling due to their large fil... more Deep-sea sponges are important contributors to carbon and nitrogen cycling due to their large filtration capacity. Species of the suborder Astrophorina form dense sponge grounds in the North Atlantic, where they serve as prey for spongivores, but also have non-trophic interactions with commensal epi- and endobionts. At the Flemish Cap (NW Atlantic) Astrophorina sponges are present in four previously described deep-sea epifaunal assemblages: the deep-sea coral assemblage, the lower slope assemblages 1 and 2, and the deep-sea sponge assemblage. To investigate their role in trophic and non-trophic interactions at the Flemish Cap, we developed trophic-/ non-trophic interaction web models for each of the four faunal assemblages using the published literature. By excluding the sponges from the models, we estimated how many trophic, facultative and obligatory non-trophic links would be lost, and how this removal affected food-web properties (number of compartments, links, link density, and...
A new Tedania species (Porifera) was collect using remotely operated vehicles during the Canadian... more A new Tedania species (Porifera) was collect using remotely operated vehicles during the Canadian mission HUD2010-029 and the British RRS Discovery Cruise DY081, on the Orphan Seamount near the Orphan Knoll, northwest Atlantic, between 2999.88 and 3450.4 m depth. Orphan Knoll is an isolated, drowned continental fragment 550 km northeast Newfoundland in the Labrador Sea. This region is biologically rich and complex and in 2007, the regional fisheries management organization operating in the area regulated that no vessel shall engage in bottom-contact fishing activities until reviewed in 2020 with a review slated at the end of this year. Members of the genus Tedania are uncommon in the temperate northern hemisphere with only six species known previously: Tedania (Tedania) anhelans; Tedania (Tedania) pilarriosae; Tedania (Tedania) suctoria; Tedania (Tedania) urgorrii; Tedania (Tedaniopsis) gurjanovae; and Tedania (Tedaniopsis) phacellina. The particular features of the new sponge we de...
Marine sponges (phylum Porifera) are leading organisms for the discovery of bioactive compounds f... more Marine sponges (phylum Porifera) are leading organisms for the discovery of bioactive compounds from nature. Their often rich and species-specific microbiota is hypothesised to be producing many of these compounds. Yet, environmental influences on the sponge-associated microbiota and bioactive compound production remain elusive. Here, we investigated the changes of microbiota and metabolomes in sponges along a depth range of 1232 m. Using 16S rRNA gene amplicon sequencing and untargeted metabolomics, we assessed prokaryotic and chemical diversities in three deep-sea sponge species:Geodia barretti,Stryphnus fortis, andWeberella bursa. Both prokaryotic communities and metabolome varied significantly with depth, which we hypothesized to be the effect of different water masses. Up to 35.5% of microbial ASVs (amplicon sequence variants) showed significant changes with depth while phylum-level composition of host microbiome remained unchanged. The metabolome varied with depth, with relati...
We report the first records of the new species Tedania (Tedaniopsis) rappi (Demospongiae, Poecilo... more We report the first records of the new species Tedania (Tedaniopsis) rappi (Demospongiae, Poecilosclerida, Tedaniidae) from the Orphan Seamount, between 2999.88 and 3449.629 m in depth.
Vazella pourtalesi presence and absence data were obtained from several different sources: DFO... more Vazella pourtalesi presence and absence data were obtained from several different sources: DFO's multispecies trawl survey conducted in the Maritimes Region between 2007 to 2017 (presences and absences), DFO optical (in-house camera/video and remotely operated vehicle) benthic surveys conducted between 2001 and 2017 (presences only), and commercial bycatch records from the Fisheries Observer Program (FOP) from 1997 to 2007, and 2010 to 2015 (presences only). The DFO multispecies trawl survey is stratified random (by depth) and conducted using primarily Western IIA trawl gear. The average distance of these tows is ~ 3.17 km. Absence records were created from null (zero) catches that occurred in the same surveys. Commercial bycatch data between 1997 to 2007 from the Fisheries Observer Program was further post-processed and validated for accuracy, while the data from 2010 to 2015 was extracted directly from the Maritimes Fishery Science Database managed by DFO. Commercial trawls ar...
Models of probability of occurrence and predicted biomass distribution have been created using ra... more Models of probability of occurrence and predicted biomass distribution have been created using random forest (RF) machine learning techniques for different invertebrate taxa in the Gulf of St. Lawrence. Response data were derived from by-catch data collected from DFO research vessel trawl surveys following a stratified random design based on depth and geographic region. Predictors were drawn from 78 environmental data layers. Occurrence models performed very well for sea pens and stalked tunicates and better than those for soft corals and sponges, with cross-validated AUC (area under the receiver operating characteristic curve) values ranging from 0.71 to 0.91. For the models based on biomass, soft corals and sea pens had the highest R2 values (0.42 and 0.37, respectively) in the southern Gulf of St. Lawrence and stalked tunicates and sea pens in the north (0.41 and 0.27, respectively). Sponges had R2 values less than 0.1 in both areas indicating poor model performance. Biomass models from RF were compared with Generalized Additive Models (GAM). In most of the cases RF and GAM models provided similar results and were both good options, although the fewer assumptions required for RF makes this method more convenient. These results could be used to identify the potential distribution of some vulnerable marine ecosystems indicator taxa and help to refine the borders of the significant benthic area polygons defining significant concentrations of these taxa as identified through the kernel density analyses. In particular these models can be used to extrapolate to areas not covered by the research vessel surveys.
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