ORCID Profile
0000-0003-3784-4533
Current Organisations
University of Otago
,
Bedford Institute of Oceanography/Fisheries and Oceans, Canada
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Publications
Editorial: Deep-sea sponge ecosystems: Knowledge-based approach towards sustainable management and conservation
Publisher: Frontiers Media SA
Date: 20-01-2023
<p class=HeadingRunIn><strong><em>Telopathes magna </em>gen. nov., spec. nov. (Cnidaria: Anthozoa: Antipatharia: Schizopathidae) from deep waters off Atlantic Canada and the
Publisher: Magnolia Press
Date: 13-08-2013
DOI: 10.11646/ZOOTAXA.3700.2.3
Abstract: A new genus and species of deep-sea antipatharian, Telopathes magna gen. nov., spec. nov., is described from the western North Atlantic off the coast of Canada. Five additional paratypes, consisting ofjuvenile to adult forms, are reported from the New England and Corner Rise Seamounts (NW Atlantic). Preliminary sequencing of a subsection of the nuclear ribosomal cistron confirmed the phylogenetic affinity of T. magna to the order Antipatharia, and in particular the family Schizopathidae. Subsequent sequencing of three mitochondrial DNA segments from nine of the 11 currently-recognized genera within the Schizopathidae revealed a well-supported phylogenetic relationship between T. magna and Stauropathes. This is the first study to use molecular techniques to elucidate the evolutionary relationships of the Schizopathidae, a family of black corals almost exclusively found in the deep sea (depths > 200 m). Telopathes is distinguished from other genera within the family Schizopathidae by its largely pinnulated stalk, sparse branching pattern to the second degree that is not restricted to a single plane, two anterolateral rows of long, simple primary pinnules, arranged alternately to sub-opposite, and colony with an adhesive base. This record of T. magna brings the total number of nominal species of Antipatharia reported to occur off eastern Canada to 12 and represents the third new genus added to the Schizopathidae since a critical review of the family by Dennis Opresko in 2002.
Nucleotide sequence of the 18S ribosomal RNA gene from the Atlantic sea scallopPlacopecten magellanicus(Gmelin, 1791)
Publisher: Oxford University Press (OUP)
Date: 1990
Climate change is likely to severely limit the effectiveness of deep-sea ABMTs in the North Atlantic
Publisher: Elsevier BV
Date: 2018
Ultrasonic and seismic constraints on crystallographic preferred orientations of the Priestley Glacier shear margin, Antarctica
Publisher: Copernicus GmbH
Date: 11-01-2022
DOI: 10.5194/TC-2021-382
Abstract: Abstract. Crystallographic preferred orientations (CPOs) are particularly important in controlling the mechanical properties of glacial shear margins. Logistical and safety considerations often make direct s ling of shear margins difficult and geophysical measurements are commonly used to constrain the CPOs. We present here the first direct comparison of seismic and ultrasonic data with measured CPOs in a polar shear margin. The measured CPO from ice s les from a 58 m deep borehole in the left lateral shear margin of the Priestley Glacier, Antarctica, is dominated by horizontal c-axes aligned sub-perpendicular to flow. A vertical seismic profile experiment with hammer shots up to 50 m away from the borehole, in four different azimuthal directions, shows velocity anisotropy of both P-waves and S-waves. Matching P-wave data to the anisotropy corresponding to CPO models defined by horizontally aligned c-axes gives two possible solutions for c-axis azimuth, one of which matches the c-axis measurements. If both P-wave and S-wave data are used, there is one best fit for azimuth and intensity of c-axis alignment that matches well the measurements. Azimuthal P-wave and S-wave ultrasonic data recorded in the laboratory on the ice core show clear anisotropy that matches that predicted from the CPO of the s les. With good quality data, azimuthal increments of 30° or less will constrain well the orientation and intensity of c-axis alignment. Our experiments provide a good framework for planning seismic surveys aimed at constraining the anisotropy of shear margins.
Mechanics and microstructure of deformed natural anisotropic ice
Publisher: Elsevier BV
Date: 10-2018
Climate‐induced changes in the suitable habitat of cold‐water corals and commercially important deep‐sea fishes in the North Atlantic
Publisher: Wiley
Date: 20-02-2020
DOI: 10.1111/GCB.14996
Genetic Variation Underlying Protein Expression in Eggs of the Marine Mussel Mytilus edulis
Publisher: Elsevier BV
Date: 2009
An improved method for the extraction and electrophoresis of proteins and active enzymes from fucalean macroalgae (Phaeophyta)
Publisher: Informa UK Limited
Date: 06-1987
Other effective area-based conservation measure promotes recovery in a cold-water coral reef
Publisher: Elsevier BV
Date: 04-2021
Benthic Habitats and the Effects of Fishing
Publisher: American Fisheries Society
Date: 2005
Isolation and Characterization of Tetranucleotide Microsatellites from Atlantic Haddock (Melanogrammus aeglefinus)
Publisher: Springer Science and Business Media LLC
Date: 09-2002
DOI: 10.1007/S10126-002-0010-4
Abstract: Five tetranucleotide microsatellite loci developed from Atlantic haddock (Melanogrammus aeglefinus) are presented. Loci were isolated using a modified magnetic bead-hybridization selection procedure that enriched for tetranucleotide microsatellites. Loci were polymorphic (3-99 alleles per locus mean, 33.2) and exhibited high levels of observed heterozygosity (0.07-0.99 mean, 0.73) in a s le of 70 haddock collected from the Scotian Shelf in the Northwest Atlantic Ocean. Primer sets for 5 tetranucleotide microsatellites, originally developed from cod (Gmo34), were also tested in Atlantic haddock one pair yielded readily detectable product and was variable in the population assayed (29 alleles heterozygosity, 0.96). These loci are suitable for kinship analyses in aquaculture-related applications, and are potentially useful for resolving population structure in the wild.
Massive silicon utilization facilitated by a benthic‐pelagic coupled feedback sustains deep‐sea sponge aggregations
Publisher: Wiley
Date: 28-09-2020
DOI: 10.1002/LNO.11610
Impacts of otter trawling on colonial epifaunal assemblages on a cobble bottom ecosystem on Western Bank (northwest Atlantic)
Publisher: Inter-Research Science Center
Date: 11-01-2006
DOI: 10.3354/MEPS306063
Myths and moderation in marine ‘metapopulations’?
Publisher: Wiley
Date: 03-2002
Molecular relationships among the Gracilariaceae (Rhodophyta): further observations on some undetermined species
Publisher: Informa UK Limited
Date: 08-1994
Influence of Water Masses on the Biodiversity and Biogeography of Deep-Sea Benthic Ecosystems in the North Atlantic
Publisher: Frontiers Media SA
Date: 21-04-2020
Assigning individual fish to populations using microsatellite DNA markers
Publisher: Wiley
Date: 06-2001
Comparison of taxa of the mussel Mytilus (Bivalvia) by analysis of the nuclear small-subunit rRNA gene sequence
Publisher: Canadian Science Publishing
Date: 12-1995
DOI: 10.1139/F95-850
Abstract: Small-subunit rRNA gene sequences (18S rDNA) were determined for Mytilus californianus and Atlantic and Pacific representatives of the blue mussel complex, Mytilus edulis, Mytilus trossulus, and Mytilus galloprovincialis (Mytilinae). A sequence from the modiolid mussel Geukensia demissa was used as the outgroup. Differences among the mytilid sequences were small, 2–10 nucleotide positions in 1825–1827 base pairs, whereas the sequence from G. demissa was 1810 base pairs long and differed from M. edulis edulis in 81 positions. The "edulis–trossulus–galloprovincialis" taxa in this study have erged from one another, and this complex appears to comprise at least six genetically distinct entities, some of which have previously held specific status. Recognition of this array may lead to the identification of morphological or biological characters that reflect the observed genetic differences.
Active buoyancy adjustment increases dispersal potential in benthic marine animals
Publisher: Wiley
Date: 02-2019
Abstract: While the study of dispersal and connectivity in the ocean typically centres on pelagic species and planktonic larval stages of benthic species, the present work explores an overlooked locomotor means in post‐settlement benthic stages that redefines their dispersal potential. Members of the echinoderm class Holothuroidea colonize a ersity of marine environments world‐wide, where they play key ecological and economical roles, making their conservation a priority. Holothuroids are commonly called sea cucumbers or sea slugs to reflect their slow movements and are assumed to disperse chiefly through pelagic larvae. The present study documents and explores their unexpected ability to actively modify their buoyancy, leading them to tumble or float at speeds orders of magnitudes faster than through benthic crawling. Two focal species representing different taxonomic orders, geographic distributions and reproductive strategies were studied over several years. Active buoyancy adjustment (ABA) was achieved through a rapid increase in water‐to‐flesh ratio by up to 740%, leading to bloating, and simultaneously detachment from the substrate. It occurred as early as 6 months post settlement in juveniles and was recorded in wild adult populations. In experimental trials, ABA was triggered by high conspecific density, decreasing salinity and increasing water turbidity. Based on field video footage, ABA‐assisted movements generated speeds of up to 90 km/day. These findings imply that displacement during planktonic larval stages may not supersede the locomotor capacity of benthic stages, challenging the notion of sedentarity. Combining the present results and anecdotal reports, ABA emerges as a generalized means of dispersal among benthic animals, with critical implications for world‐wide management and conservation of commercially and ecologically significant species.
Constraints on Alpine Fault (New Zealand) mylonitization temperatures and the geothermal gradient from Ti-in-quartz thermobarometry
Publisher: Copernicus GmbH
Date: 25-09-2018
Abstract: Abstract. We constrain the thermal state of the central Alpine Fault using approximately 750 Ti-in-quartz secondary ion mass spectrometer (SIMS) analyses from a suite of variably deformed mylonites. Ti-in-quartz concentrations span more than 1 order of magnitude from 0.24 to ∼ 5 ppm, suggesting recrystallization of quartz over a 300 °C range in temperature. Most Ti-in-quartz concentrations in mylonites, protomylonites, and the Alpine Schist protolith are between 2 and 4 ppm and do not vary as a function of grain size or bulk rock composition. Analyses of 30 large, inferred-remnant quartz grains ( 250 µm) as well as late, crosscutting, chlorite-bearing quartz veins also reveal restricted Ti concentrations of 2–4 ppm. These results indicate that the vast majority of Alpine Fault mylonitization occurred within a restricted zone of pressure–temperature conditions where 2–4 ppm Ti-in-quartz concentrations are stable. This constrains the deep geothermal gradient from the Moho to about 8 km to a slope of 5 °C km−1. In contrast, the small grains (10–40 µm) in ultramylonites have lower Ti concentrations of 1–2 ppm, indicating a deviation from the deeper pressure–temperature trajectory during the latest phase of ductile deformation. These constraints suggest an abrupt, order of magnitude change in the geothermal gradient to an average of about 60 °C km−1 at depths shallower than about 8 km, i.e., within the seismogenic zone. Anomalously, the lowest-Ti quartz (0.24–0.7 ppm) occurs away from the fault in protomylonites, suggesting that the outer fault zone experienced minor plastic deformation late in the exhumation history when more fault-proximal parts of the fault were deforming exclusively by brittle processes.
Paternal mtDNA and Maleness Are Co-Inherited but Not Causally Linked in Mytilid Mussels
Publisher: Public Library of Science (PLoS)
Date: 11-09-2009
The nuclear 18S ribosomal RNA gene of the red alga Hildenbrandia rubra contains a group I intron
Publisher: Oxford University Press (OUP)
Date: 1993
Using electron backscatter diffraction to measure full crystallographic orientation in Antarctic land-fast sea ice
Publisher: Cambridge University Press (CUP)
Date: 12-09-2018
DOI: 10.1017/JOG.2018.67
Abstract: We have mapped the full crystallographic orientation of sea ice using electron backscatter diffraction (EBSD). This is the first time EBSD has been used to study sea ice. Platelet ice is a feature of sea ice near ice shelves. Ice crystals accumulate as an unconsolidated sub-ice platelet layer beneath the columnar ice (CI), where they are subsumed by the advancing sea–ice interface to form incorporated platelet ice (PI). As is well known, in CI the crystal preferred orientation comprises dominantly horizontal c -axes, while PI has c -axes varying between horizontal and vertical. For the first time, this study shows the a -axes of CI and PI are not random. Misorientation analysis has been used to illuminate the possible drivers of these alignments. In CI the misorientation angle distribution from random pairs and neighbour pairs of grains are indistinguishable, indicating the distributions are a consequence of crystal preferred orientation. Geometric selection during growth will develop the a -axis alignment in CI if ice growth in water is fastest parallel to the a -axis, as has previously been hypothesised. In contrast, in PI random-pair and neighbour-pair misorientation distributions are significantly different, suggesting mechanical rotation of crystals at grain boundaries as the most likely explanation.
The Meso- and Bathypelagic Fishes in a Large Submarine Canyon: Assemblage Structure of the Principal Species in the Gully Marine Protected Area
Publisher: Frontiers Media SA
Date: 27-03-2020
An analysis of the community composition of the Xiphophora gladiata dominated subzone of the Tasmanian sublittoral fringe
Publisher: The Royal Society of Tasmania
Date: 1989
Seasonal Variability in Near-bed Environmental Conditions in the Vazella pourtalesii Glass Sponge Grounds of the Scotian Shelf
Publisher: Frontiers Media SA
Date: 08-01-2021
DOI: 10.3389/FMARS.2020.597682
Abstract: The Scotian Shelf harbors unique aggregations of the glass sponge Vazella pourtalesii that provides an important habitat for benthic and pelagic fauna. Recent studies have shown that these sponge grounds have persisted in the face of strong inter-annual and multi-decadal variability in temperature and salinity. However, little is known of these environmental characteristics on hourly-seasonal time scales. This study presents the first hydrodynamic observations and associated (food) particle supply mechanisms for the Vazella sponge grounds, highlighting the influence of natural variability in environmental conditions on sponge growth and resilience. Near-bottom environmental conditions were characterized by high temporal resolution data collected with a benthic lander, deployed during a period of 10 months in the Sambro Bank Sponge Conservation Area. The lander was equipped with temperature and oxygen sensors, a current meter, a sediment trap and a video camera. In addition, water column profiles of temperature and salinity were collected in an array across the sponge grounds from high to lower sponge presence probability. Over the course of the lander deployment, temperature fluctuated between 8.8–12°C with an average of 10.6 ± 0.4°C. Dissolved oxygen concentration was on average 6.3 mg l –1 , and near-bottom current speed was on average 0.12 m s –1 , with peaks up to 0.47 m s –1 . Semi-diurnal tidal currents promoted constant resuspension of particulate matter in the benthic boundary layer. Surface storm events episodically caused extremely turbid conditions on the seafloor that persisted for several days, with particles being resuspended to more than 13 m above the seabed. The carbon flux in the near-bottom sediment trap peaked during storm events and also after a spring bloom in April, when fresh phytodetritus was observed in the bottom boundary layer. While resuspension events can represent a major stressor for sponges, limiting their filtration capability and remobilizing them, episodes of strong currents and lateral particle transport likely play an important role in food supply and the replenishment of nutrients and oxygen. Our results contextualize human-induced threats such as bottom fishing and climate change by providing more knowledge of the natural environmental conditions under which sponge grounds persist.
Cooperation between passive and active silicon transporters clarifies the ecophysiology and evolution of biosilicification in sponges
Publisher: American Association for the Advancement of Science (AAAS)
Date: 10-07-2020
Abstract: Molecular mechanisms for Si transport constrain the evolution and ecological adaptability of sponges.
Relationships among geographically distant populations of Gracilaria verrucosa (Gracilariales, Rhodophyta) and related species
Publisher: Informa UK Limited
Date: 12-1990
Ultrasonic and seismic constraints on crystallographic preferred orientations of the Priestley Glacier shear margin, Antarctica
Publisher: Copernicus GmbH
Date: 24-08-2022
Abstract: Abstract. Crystallographic preferred orientations (CPOs) are particularly important in controlling the mechanical properties of glacial shear margins. Logistical and safety considerations often make direct s ling of shear margins difficult, and geophysical measurements are commonly used to constrain the CPOs. We present here the first direct comparison of seismic and ultrasonic data with measured CPOs in a polar shear margin. The measured CPO from ice s les from a 58 m deep borehole in the left lateral shear margin of the Priestley Glacier, Antarctica, is dominated by horizontal c axes aligned sub-perpendicularly to flow. A vertical-seismic-profile experiment with hammer shots up to 50 m away from the borehole, in four different azimuthal directions, shows velocity anisotropy of both P waves and S waves. Matching P-wave data to the anisotropy corresponding to CPO models defined by horizontally aligned c axes gives two possible solutions for the c-axis azimuth, one of which matches the c-axis measurements. If both P-wave and S-wave data are used, there is one best fit for the azimuth and intensity of c-axis alignment that matches the measurements well. Azimuthal P-wave and S-wave ultrasonic data recorded in the laboratory on the ice core show clear anisotropy of P-wave and S-wave velocities in the horizontal plane that match that predicted from the CPO of the s les. With quality data, azimuthal increments of 30∘ or less will constrain well the orientation and intensity of c-axis alignment. Our experiments provide a good framework for planning seismic surveys aimed at constraining the anisotropy of shear margins.
Climate-Change Refugia for the Bubblegum Coral Paragorgia arborea in the Northwest Atlantic
Publisher: Frontiers Media SA
Date: 11-07-2022
DOI: 10.3389/FMARS.2022.863693
Abstract: The large, habitat-forming bubblegum coral, Paragorgia arborea , is a vulnerable marine ecosystem indicator with an antitropical distribution. Dense aggregations of the species have been protected from bottom-contact fishing in the Scotian Shelf bioregion off Nova Scotia, Canada in the northwest Atlantic Ocean. Recently, basin-scale habitat suitability ensemble modeling has projected an alarming loss of 99% of suitable habitat for this species across the North Atlantic by 2100. Here, a regional reassessment of the predicted distribution of this species in the bioregion, using both machine learning (random forest) and generalized additive model (GAM) frameworks, including projection to 2046−2065, was undertaken. Extrapolation diagnostics were applied to determine the degree to which the models projected into novel covariate space (i.e., extrapolation) in order to avoid erroneous inferences. The best predictors of the species’ distribution were a suite of temporally-invariant terrain variables that identified suitable habitat along the upper continental slope. Additional predictors, projected to vary with future ocean climatologies, identified areas of the upper slope in the eastern portion of the study area that will remain within suitable ranges for P. arborea at least through to the mid-century. Additionally, 3-D Lagrangian particle tracking simulations indicated potential for both connectivity among known occurrence sites and existing protected areas, and for colonization of unsurveyed areas predicted to have suitable habitat, from locations of known occurrence. These results showed that extirpation of this iconic species from the Scotian Shelf bioregion is unlikely over the next decades. Potential climate refugia were identified and results presented in the context of protected area network design properties of representativity, connectivity, adequacy, viability and resilience.
Seafloor biodiversity of Canada's three oceans: Patterns, hotspots and potential drivers
Publisher: Wiley
Date: 09-12-2019
DOI: 10.1111/DDI.13013
Influence of Benthic Macrofauna as a Spatial Structuring Agent for Juvenile Haddock (Melanogrammus aeglefinus) on the Eastern Scotian Shelf, Atlantic Canada
Publisher: Public Library of Science (PLoS)
Date: 20-09-2016
Atlantic capelin (Mallotus villosus) tetranucleotide microsatellites
Publisher: Wiley
Date: 11-01-2005
Proteomic Analysis of Eggs from Mytilus edulis Females Differing in Mitochondrial DNA Transmission Mode
Publisher: Elsevier BV
Date: 11-2013
Development, characterisation, inheritance, and cross-species utility of American lobster (Homarus americanus) microsatellite and mtDNA PCR-RFLP markers
Publisher: Canadian Science Publishing
Date: 02-2003
DOI: 10.1139/G02-105
Abstract: Effective management of exploited species demands contemporary knowledge of population structure and mating patterns. Genetic markers can prove useful in providing this knowledge. Despite its commercial importance, genetic markers for American lobster (Homarus americanus) are limited. We developed 12 tetra- and 1 trinucleotide microsatellite loci for American lobster that exhibit little stuttering after PCR lification. Gene ersity of these loci ranged from 0.516 to 0.929. A four-locus multiplex permits rapid genotyping of progeny in parentage experiments with a paternity exclusion probability over the four loci of 97.8%. We examined the loci for conformity to Hardy-Weinberg expectations (HWE) and linkage using in iduals from one location and found that four loci deviated from HWE. We also tested inheritance and pairwise linkage using 48 embryos from each of two females. With the exception of two loci that were derived from the same clone and separated by 72 bp, no evidence of linkage was found. We, for the first time, demonstrate the occurrence of multiple paternity in American lobster. We also observed an apparent occurrence of dispermic androgenesis, possibly the first documentation of such an event within a species. Ten of the loci lified in European lobster (Homarus gammarus), although two were monomorphic and one deviated significantly from HWE. We quantified mitochondrial DNA (mtDNA) sequence variation through the use of PCR lification of two DNA fragments, followed by digestion with restriction enzymes eight haplotypes were detected. One of the two fragments lified in European lobster. Both sets of markers should prove useful for population discrimination purposes, and the microsatellites, in particular the four-locus multiplex, should prove highly amenable to rapidly addressing questions about mating patterns.Key Words: low-stutter microsatellites, mtDNA PCRRFLP, multiple paternity, dispermic androgenesis, American lobster.
PHYLOGENETIC-RELATIONSHIPS OF SPECIES OF UNCERTAIN TAXONOMIC POSITION WITHIN THE ACROCHAETIALES-PALMARIALES COMPLEX (RHODOPHYTA) - INFERENCES FROM PHENOTYPIC AND 18S RDNA SEQUENCE DATA
Publisher: Wiley
Date: 08-1995
Deep-sea sponge grounds enhance diversity and abundance of epibenthic megafauna in the Northwest Atlantic
Publisher: Oxford University Press (OUP)
Date: 16-08-2013
Abstract: Beazley, L. I., Kenchington E. L., Murillo, F. J., and Sacau, M. 2013. Deep-sea sponge grounds enhance ersity and abundance of epibenthic megafauna in the Northwest Atlantic. – ICES Journal of Marine Science, 70: . The influence of structure-forming deep-water sponge grounds on the composition, ersity, and abundance of the local epibenthic megafaunal community of the Flemish Pass area, Northwest Atlantic was statistically assessed. These habitats are considered vulnerable marine ecosystems and, therefore, warrant conservation measures to protect them from bottom fishing activities. The epibenthic megafauna were quantified from four photographic transects, three of which were located on the western slope of the Flemish Cap with an overall depth range of 444–940 m, and the fourth in the southern Flemish Pass between 1328 and 1411 m. We observed a erse megafaunal community dominated by large numbers of ophiuroids and sponges. On the slope of the Flemish Cap, sponge grounds were dominated by axinellid and polymastid sponges, while the deeper sponge ground in the southern Flemish Pass was formed mainly by geodiids and Asconema sp. The presence of structure-forming sponges was associated with a higher bio ersity and abundance of associated megafauna compared with non-sponge habitat. The composition of megafauna significantly differed between sponge grounds and non-sponge grounds and also between different sponge morphologies. Surface chlorophyll a and near-bottom salinity were important environmental determinants in generalized linear models of megafaunal species richness and abundance.
Nucleotide sequences of 18S ribosomal RNA genes from the red algae Gracilaria tikvahiae McLachlan, Gracilaria verrucosa (hudson) papenfuss and Gracilariopsis sp+
Publisher: Oxford University Press (OUP)
Date: 1990
Epibenthic assemblages of the Tail of the Grand Bank and Flemish Cap (northwest Atlantic) in relation to environmental parameters and trawling intensity
Publisher: Elsevier BV
Date: 03-2016
Pleistocene glaciation events shape genetic structure across the range of the American lobster, Homarus americanus
Publisher: Wiley
Date: 04-2009
Feeding biology of Ophiura sarsii Lütken, 1855 on Banquereau bank and the effects of fishing
Publisher: Springer Science and Business Media LLC
Date: 27-05-2009
A Microbial Nitrogen Engine Modulated by Bacteriosyncytia in Hexactinellid Sponges: Ecological Implications for Deep-Sea Communities
Publisher: Frontiers Media SA
Date: 17-03-2021
DOI: 10.3389/FMARS.2021.638505
Abstract: Hexactinellid sponges are common in the deep sea, but their functional integration into those ecosystems remains poorly understood. The phylogenetically related species Schaudinnia rosea and Vazella pourtalesii were herein incubated for nitrogen and phosphorous, returning markedly different nutrient fluxes. Transmission electron microscopy (TEM) revealed S. rosea to host a low abundance of extracellular microbes, while Vazella pourtalesii showed higher microbial abundance and hosted most microbes within bacteriosyncytia, a novel feature for Hexactinellida. Amplicon sequences of the microbiome corroborated large between-species differences, also between the sponges and the seawater of their habitats. Metagenome-assembled genome of the V. pourtalesii microbiota revealed genes coding for enzymes operating in nitrification, denitrification, dissimilatory nitrate reduction to ammonium, nitrogen fixation, and ammonia/ammonium assimilation. In the nitrification and denitrification pathways some enzymes were missing, but alternative bridging routes allow the microbiota to close a N cycle in the holobiont. Interconnections between aerobic and anaerobic pathways may facilitate the sponges to withstand the low-oxygen conditions of deep-sea habitats. Importantly, various N pathways coupled to generate ammonium, which, through assimilation, fosters the growth of the sponge microbiota. TEM showed that the farmed microbiota is digested by the sponge cells, becoming an internal food source. This microbial farming demands more ammonium that can be provided internally by the host sponges and some 2.6 million kg of ammonium from the seawater become annually consumed by the aggregations of V. pourtalesii . Such ammonium removal is likely impairing the development of the free-living bacterioplankton and the survival chances of other sponge species that feed on bacterioplankton. Such nutritional competitive exclusion would favor the monospecific character of the V. pourtalesii aggregations. These aggregations also affect the surrounding environment through an annual release of 27.3 million kg of nitrite and, in smaller quantities, of nitrate and phosphate. The complex metabolic integration among the microbiota and the sponge suggests that the holobiont depends critically on the correct functioning of its N-driven microbial engine. The metabolic intertwining is so delicate that it changed after moving the sponges out of their habitat for a few days, a serious warning on the conservation needs of these sponge aggregations.
Differential Segregation Patterns of Sperm Mitochondria in Embryos of the Blue Mussel (Mytilus edulis)
Publisher: Oxford University Press (OUP)
Date: 02-2004
DOI: 10.1093/GENETICS/166.2.883
Abstract: In Mytilus, females carry predominantly maternal mitochondrial DNA (mtDNA) but males carry maternal mtDNA in their somatic tissues and paternal mtDNA in their gonads. This phenomenon, known as doubly uniparental inheritance (DUI) of mtDNA, presents a major departure from the uniparental transmission of organelle genomes. Eggs of Mytilus edulis from females that produce exclusively daughters and from females that produce mostly sons were fertilized with sperm stained with MitoTracker Green FM, allowing observation of sperm mitochondria in the embryo by epifluorescent and confocal microscopy. In embryos from females that produce only daughters, sperm mitochondria are randomly dispersed among blastomeres. In embryos from females that produce mostly sons, sperm mitochondria tend to aggregate and end up in one blastomere in the two- and four-cell stages. We postulate that the aggregate eventually ends up in the first germ cells, thus accounting for the presence of paternal mtDNA in the male gonad. This is the first evidence for different behaviors of sperm mitochondria in developing embryos that may explain the tight linkage between gender and inheritance of paternal mitochondrial DNA in species with DUI.
Sponge Grounds as Key Marine Habitats: A Synthetic Review of Types, Structure, Functional Roles, and Conservation Concerns
Publisher: Springer International Publishing
Date: 2015
A blueprint for integrating scientific approaches and international communities to assess basin-wide ocean ecosystem status
Publisher: Springer Science and Business Media LLC
Date: 19-01-2023
DOI: 10.1038/S43247-022-00645-W
Abstract: Ocean ecosystems are at the forefront of the climate and bio ersity crises, yet we lack a unified approach to assess their state and inform sustainable policies. This blueprint is designed around research capabilities and cross-sectoral partnerships. We highlight priorities including integrating basin-scale observation, modelling and genomic approaches to understand Atlantic oceanography and ecosystem connectivity improving ecosystem mapping identifying potential tipping points in deep and open ocean ecosystems understanding compound impacts of multiple stressors including warming, acidification and deoxygenation enhancing spatial and temporal management and protection. We argue that these goals are best achieved through partnerships with policy-makers and community stakeholders, and promoting research groups from the South Atlantic through investment and engagement. Given the high costs of such research (€800k to €1.7M per expedition and €30–40M for a basin-scale programme), international cooperation and funding are integral to supporting science-led policies to conserve ocean ecosystems that transcend jurisdictional borders.
The Fate of Paternal Mitochondrial DNA in Developing Female Mussels, Mytilus edulis: Implications for the Mechanism of Doubly Uniparental Inheritance of Mitochondrial DNA
Publisher: Oxford University Press (OUP)
Date: 1998
DOI: 10.1093/GENETICS/148.1.341
Abstract: Species of the marine mussel family Mytilidae have two types of mitochondrial DNA: one that is transmitted from the mother to both female and male offspring (the F type) and one that is transmitted from the father to sons only (the M type). By using pair matings that produce only female offspring or a mixture of female and male offspring and a pair of oligonucleotide primers that lify part of the COIII gene of the M but not the F mitochondrial genome, we demonstrate that both male and female embryos receive M mtDNA through the sperm and that within 24 hr after fertilization the M mtDNA is eliminated or is drastically reduced in female embryos but maintained in male embryos. These observations are important for understanding the relationship between mtDNA transmission and sex determination in species with doubly uniparental inheritance of mitochondrial DNA.
Processes of physical change to the seabed and bivalve recruitment over a 10-year period following experimental hydraulic clam dredging on Banquereau, Scotian Shelf
Publisher: Elsevier BV
Date: 2015
A preliminary investigation of the order Bangiales (Bangiophycidae, Rhodophyta) based on sequences of nuclear small‐subunit ribosomal RNA genes
Publisher: Wiley
Date: 06-1995
Barcoding Atlantic Canada’s mesopelagic and upper bathypelagic marine fishes
Publisher: Public Library of Science (PLoS)
Date: 20-09-2017
Marine epibenthic functional diversity on Flemish Cap (north‐west Atlantic)—Identifying trait responses to the environment and mapping ecosystem functions
Publisher: Wiley
Date: 29-01-2020
DOI: 10.1111/DDI.13026
An evaluation of benthic community structure in and around the Sackville Spur closed area (Northwest Atlantic) in relation to the protection of vulnerable marine ecosystems
Publisher: Oxford University Press (OUP)
Date: 2012
Abstract: Barrio Froján, C. R. S., MacIsaac, K. G., McMillan, A. K., del Mar Sacau Cuadrado, M., Large, P. A., Kenny, A. J., Kenchington, E., and de Cárdenas González, E. 2012. An evaluation of benthic community structure in and around the Sackville Spur closed area (Northwest Atlantic) in relation to the protection of vulnerable marine ecosystems. – ICES Journal of Marine Science, 69: 213–222. The benthic macrofaunal community structure is investigated within and around a closed area at Sackville Spur in the Northwest Atlantic to ascertain whether continued exclusion of bottom fishing can be justified. This and other similar closed areas have been introduced by the Northwest Atlantic Fisheries Organisation (NAFO) to protect areas of likely occurrence of taxa that are indicative of vulnerable marine ecosystems (VMEs) from the damaging effects of bottom-contact fishing gear. Results reveal subtle yet significant differences in macrofaunal assemblage composition and community structure between inside and outside the closed area, between above and below the 1200-m depth contour (i.e. the historical depth limit of fishing), and between areas where dense sponge spicule mats are either present or absent. Differences were observed in many assemblage metrics however, the most revealing was the greater abundance, biomass, ersity, and number of VME indicative taxa inside the closed area than outside. Overall community composition is also significantly different between treatments. Depth, sediment temperature, and the proportion of clay within sediments are important in shaping the faunal assemblage. The importance of the effects of fishing is discussed, although it is not possible to ascertain if fishing is the direct cause behind observed differences in the macrofaunal assemblage. A continued closure of the area is recommended, as well as options for streamlining the evaluation process of other closed areas.
Exploring ecosystem‐based management in the North Atlantic
Publisher: Wiley
Date: 08-2022
DOI: 10.1111/JFB.15168
Abstract: The United States, the EU and Canada established a trilateral working group on the ecosystem approach to ocean health and stressors under the Atlantic Ocean Research Alliance. Recognizing the Atlantic Ocean as a shared resource and responsibility, the working group sought to advance understanding of the Atlantic Ocean and its dynamic systems to improve ocean health, enhance ocean stewardship and promote the sustainable use and management of its resources. This included consideration of multiple ocean‐use sectors such as fishing, shipping, tourism and offshore energy. The working group met for 4 years and worked through eight steps that covered the development of common language as a basis for collaboration, challenges of stakeholder engagement, review of the governance mandates, exploring the links between sectors and ecosystems effects, identifying gaps in knowledge and uptake of science, identification of tools for ecosystem‐based management, customary best practice for tool development and communication of key research priorities. The key findings were that ecosystem‐based management enables new benefits and opportunities, and that we need to make the business case. Further findings were that adequate mandates and effective tools exist for ecosystem‐based management, and that ecosystem‐based management urgently requires integration of human dimensions, so we must ersify the conversation. In addition, it was found that stakeholders do not see their stake in ecosystem‐based management, so greater engagement with stakeholders and targeting of ocean literacy is required and a sustainable future requires a sustained investment in ecosystem‐based management, so long‐term commitment is key.
The summer assemblage of large pelagic Crustacea in the Gully submarine canyon: Major patterns
Publisher: Elsevier BV
Date: 06-2014
Limited depth zonation among bathyal epibenthic megafauna of the Gully submarine canyon, northwest Atlantic
Publisher: Elsevier BV
Date: 06-2014
The Northwest Atlantic Fisheries Organization Roadmap for the development and implementation of an Ecosystem Approach to Fisheries: structure, state of development, and challenges
Publisher: Elsevier BV
Date: 02-2019
The Hexactinellid Deep-Water Sponge Vazella pourtalesii (Schmidt, 1870) (Rossellidae) Copes With Temporarily Elevated Concentrations of Suspended Natural Sediment
Publisher: Frontiers Media SA
Date: 24-03-2021
DOI: 10.3389/FMARS.2021.611539
Abstract: Plumes of re-suspended sediment potentially smother and clog the aquiferous system of filter-feeding sponges with unknown implications for their health. For the first time, we examined the physiological responses of repeated exposure to natural sediment in the glass sponge Vazella pourtalesii , which forms dense sponge grounds in Emerald Basin off Nova Scotia, Canada. Ex situ chamber-based measurements of bacterial clearance and oxygen consumption (respiration) rates indicated that in iduals subjected to elevated concentrations of suspended sediment expressed normal clearance and respiration rates over 7 days of sediment exposure, indicating an ability to cope with elevated concentrations of indigestible sediment particles. However, clearance rates significantly declined after 14 days of sediment exposure, suggesting an inability to cope with long-term exposure to increased sediment load. Therefore, long-term exposure to elevated concentrations of suspended sediment should be avoided in order to minimize adverse effects on the abundant Vazella sponge grounds.
Expression of M6 and M7 lysin in Mytilus edulis is not restricted to sperm, but occurs also in oocytes and somatic tissue of males and females
Publisher: Wiley
Date: 29-06-2012
DOI: 10.1002/MRD.22056
Abstract: Sperm proteins of marine sessile invertebrates have been extensively studied to understand the molecular basis of reproductive isolation. Apart from molecules such as bindin of sea urchins or lysin of abalone species, the acrosomal protein M7 lysin of Mytilus edulis has been analyzed. M7 lysin was found to be under positive selection, but mechanisms driving the evolution of this protein are not fully understood. To explore functional aspects, this study investigated the protein expression pattern of M7 and M6 lysin in gametes and somatic tissue of male and female M. edulis. The study employs a previously published monoclonal antibody (G26-AG8) to investigate M6 and M7 lysin protein expression, and explores expression of both genes. It is shown that these proteins and their encoding genes are expressed in gametes and somatic tissue of both sexes. This is in contrast to sea urchin bindin and abalone lysin, in which gene expression is strictly limited to males. Although future studies need to clarify the functional importance of both acrosomal proteins in male and female somatic tissue, new insights into the evolution of sperm proteins in marine sessile invertebrates are possible. This is because proteins with male-specific expression (bindin, lysin) might evolve differently than proteins with expression in both sexes (M6/M7 lysin), and the putative function of both proteins in females opens the possibility that the evolution of M6/M7 lysin is under sexual antagonistic selection, for ex le, mutations beneficial to the acrosomal function that are less beneficial the function in somatic tissue of females.
A molecular phylogeny of the marine red algae (Rhodophyta) based on the nuclear small-subunit rRNA gene.
Publisher: Proceedings of the National Academy of Sciences
Date: 19-07-1994
Abstract: A phylogeny of marine Rhodophyta has been inferred by a number of methods from nucleotide sequences of nuclear genes encoding small subunit rRNA from 39 species in 15 orders. Sequence ergences are relatively large, especially among bangiophytes and even among congeners in this group. Subclass Bangiophycidae appears polyphyletic, encompassing at least three lineages, with Porphyridiales distributed between two of these. Subclass Florideophycidae is monophyletic, with Hildenbrandiales, Corallinales, Ahnfeltiales, and a close association of Nemaliales, Acrochaetiales, and Palmariales forming the four deepest branches. Cermiales may represent a convergence of vegetative and reproductive morphologies, as family Ceramiaceae is at best weakly related to the rest of the order, and one of its members appears to be allied to Gelidiales. Except for Gigartinales, for which more data are required, the other florideophyte orders appear distinct and taxonomically justified. A good correlation was observed with taxonomy based on pit-plug ultrastructure. Tests under maximum-likelihood and parsimony of alternative phylogenies based on structure and chemistry refuted suggestions that Acrochaetiales is the most primitive florideophyte order and that Gelidiales and Hildenbrandiales are sister groups.
PHYLOGENETIC-RELATIONSHIPS IN THE GRACILARIALES (RHODOPHYTA) AS DETERMINED BY 18S RDNA SEQUENCES
Publisher: Informa UK Limited
Date: 11-1992
Evidence That the Large Noncoding Sequence Is the Main Control Region of Maternally and Paternally Transmitted Mitochondrial Genomes of the Marine Mussel (Mytilus spp.)
Publisher: Oxford University Press (OUP)
Date: 06-2004
DOI: 10.1534/GENETICS.103.026187
Abstract: Both the maternal (F-type) and paternal (M-type) mitochondrial genomes of the Mytilus species complex M. edulis/galloprovincialis contain a noncoding sequence between the l-rRNA and the tRNATyr genes, here called the large unassigned region (LUR). The LUR, which is shorter in M genomes, is capable of forming secondary structures and contains motifs of significant sequence similarity with elements known to have specific functions in the sea urchin and the mammalian control region. Such features are not present in other noncoding regions of the F or M Mytilus mtDNA. The LUR can be ided on the basis of indels and nucleotide variation in three domains, which is reminiscent of the tripartite structure of the mammalian control region. These features suggest that the LUR is the main control region of the Mytilus mitochondrial genome. The middle domain has erged by only 1.5% between F and M genomes, while the average ergence over the whole molecule is ∼20%. In contrast, the first domain is among the most ergent parts of the genome. This suggests that different parts of the LUR are under different selection constraints that are also different from those acting on the coding parts of the molecule.
Water mass characteristics and associated fauna of a recently discovered Lophelia pertusa (Scleractinia: Anthozoa) reef in Greenlandic waters
Publisher: Springer Science and Business Media LLC
Date: 12-05-2016
Crystallographic preferred orientations of ice deformed in direct-shear experiments at low temperatures
Publisher: Copernicus GmbH
Date: 02-2019
Abstract: Abstract. Synthetic polycrystalline ice was sheared at temperatures of −5, −20 and −30 ∘C, to different shear strains, up to γ=2.6, equivalent to a maximum stretch of 2.94 (final line length is 2.94 times the original length). Cryo-electron backscatter diffraction (EBSD) analysis shows that basal intracrystalline slip planes become preferentially oriented parallel to the shear plane in all experiments, with a primary cluster of crystal c axes (the c axis is perpendicular to the basal plane) perpendicular to the shear plane. In all except the two highest-strain experiments at −30 ∘C, a secondary cluster of c axes is observed, at an angle to the primary cluster. With increasing strain, the primary c-axis cluster strengthens. With increasing temperature, both clusters strengthen. In the −5 ∘C experiments, the angle between the two clusters reduces with strain. The c-axis clusters are elongated perpendicular to the shear direction. This elongation increases with increasing shear strain and with decreasing temperature. Highly curved grain boundaries are more prevalent in s les sheared at higher temperatures. At each temperature, the proportion of curved boundaries decreases with increasing shear strain. Subgrains are observed in all s les. Microstructural interpretations and comparisons of the data from experimentally sheared s les with numerical models suggest that the observed crystallographic orientation patterns result from a balance of the rates of lattice rotation (during dislocation creep) and growth of grains by strain-induced grain boundary migration (GBM). GBM is faster at higher temperatures and becomes less important as shear strain increases. These observations and interpretations provide a hypothesis to be tested in further experiments and using numerical models, with the ultimate goal of aiding the interpretation of crystallographic preferred orientations in naturally deformed ice.
Connectivity modelling of areas closed to protect vulnerable marine ecosystems in the northwest Atlantic
Publisher: Elsevier BV
Date: 2019
Immediate impacts and recovery trajectories of macrofaunal communities following hydraulic clam dredging on Banquereau, eastern Canada
Publisher: Oxford University Press (OUP)
Date: 2005
DOI: 10.1016/J.ICESJMS.2005.03.009
Abstract: A hydraulic clam dredging experiment, designed to mimic offshore commercial dredging practices, was carried out at a depth of approximately 70 m on a sandy seabed on Banquereau, on the Scotian Shelf, eastern Canada. The experiment was designed to study the separate and combined effects of dredging through three treatment boxes (Dredging Only, Dredging and Discarding, Discarding Only) and two spatially separated reference boxes. In all, 270 taxa were identified from grab s les. Of these, four bivalves are targeted in the commercial fishery (Arctica islandica, Cyrtodaria siliqua, Mactromeris polynyma, and Serripes groenlandicus) while 266 taxa were non-target species. S le biomass was dominated by the propellerclam, C. siliqua, and the echinoderm, Echinarachnius parma, while the polychaete, Spiophanes bombyx, was the numerical dominant. The dredges captured 33 invertebrate and two fish taxa, although % of the catch biomass comprised propellerclams and echinoderms. Immediately after dredging, most macrofaunal species decreased in abundance, with the greatest declines inside dredge furrows (which covered 53–68% of the area inside the dredged boxes). Large numbers of propellerclams were excavated to the seabed surface, with a large proportion showing massive damage. There were few signs of discards on the sediment surface. Recovery trajectories of target and non-target species were followed for 2 years. Following initial declines in abundance and biomass of most taxa immediately after dredging, there were marked increases in abundance of polychaetes and hipods after 1 year. Two years after dredging, abundances of opportunistic species were generally elevated by ≫100% relative to pre-dredging levels. Two years after dredging, average taxonomic distinctness had decreased (i.e. taxonomic relatedness between species had increased) due, in part, to increased numbers of species of certain polychaetes and hipods, while communities had become numerically dominated (50–70%) by S. bombyx. It is concluded that the disturbed community was still in the colonizing phase 2 years after dredging. The mobile brittlestar, Ophiura sarsi, displayed increases in abundance ranging from 200% to 300% in the dredged and reference boxes over the 2-year post-dredging. A similar response of non-target macrofauna in the reference boxes suggests, possibly, a coincident natural recruitment pulse. Dredging resulted in pronounced, sustained reductions in biomass (up to 67%) of the target bivalves with no signs of recovery after 2 years. Recruitment of target bivalves ( -mm shell length) was very low throughout the experimental area during this interval.
From Sea to Sea: Canada's Three Oceans of Biodiversity
Publisher: Public Library of Science (PLoS)
Date: 31-08-2010
Small-scale distributional pattern in Xiphophora gladiata (Labillardiere) Montagne ex Kjellman (Fucales, Phaeophyta)
Publisher: Informa UK Limited
Date: 06-1987
SPATIAL VARIATION PATTERNS IN THE MARINE MACROALGA XIPHOPHORA GLADIATA SSP. GLADIATA (PHAEOPHYTA). II. MORPHOLOGICAL VARIATION OVER LARGE SPATIAL SCALES1
Publisher: Wiley
Date: 09-1990
High prevalence of multiple paternity in the deep-sea shrimp Acanthephyra pelagica
Publisher: Springer Science and Business Media LLC
Date: 26-03-2016
Use of Marine Genetic Resources
Publisher: Cambridge University Press
Date: 17-04-2017
Genetic differentiation in relation to marine landscape in a broadcast‐spawning bivalve mollusc (Placopecten magellanicus)
Publisher: Wiley
Date: 12-05-2006
A Numerical Taxonomic Study of Fucus Distichus (Phaeophyta)
Publisher: Cambridge University Press (CUP)
Date: 05-1985
DOI: 10.1017/S0025315400050530
Abstract: The genus Fucus L. is widely distributed through the cool temperate waters of the north Atlantic and north Pacific oceans. The very large number of sub-generic taxa ( 100) previously recognized was reduced by Powell (1963) to only 6 species. In his revision, Powell recognized F. distichus L. emend. Powell as the most variable of these. He classified the intra-specific variation in this species into 4 sub-species: F. distichus distichus, F. distichus anceps (Harv. et Ward ex. Carruthers) Powell, F. distichus evanescens (C.Ag) Powell and F. distichus edentatus (Pyl.) Powell. Because of reports that intermediate forms existed in Iceland (Jonsson, 1903) and the Faeröes (Börgesen, 1902), Powell (1957 a , b ) decided to use sub-specific status rather than specific designation for these 4 taxa. However, within North America the 4 sub-species of F. distichus were often assigned specific rank (e.g. Taylor, 1957).
The environmental interactions of tidal and wave energy generation devices
Publisher: Elsevier BV
Date: 2012
Associations of demersal fish with sponge grounds on the continental slopes of the northwest Atlantic
Publisher: Inter-Research Science Center
Date: 12-03-2013
DOI: 10.3354/MEPS10127
A new approach to prioritizing marine fish and shellfish populations for conservation
Publisher: Wiley
Date: 12-2001
Drivers of epibenthic megafaunal composition in the sponge grounds of the Sackville Spur, northwest Atlantic
Publisher: Elsevier BV
Date: 04-2015
Deep-sea sponge grounds of the Flemish Cap, Flemish Pass and the Grand Banks of Newfoundland (Northwest Atlantic Ocean): Distribution and species composition
Publisher: Informa UK Limited
Date: 11-2012
Removal of deep-sea sponges by bottom trawling in the Flemish Cap area: conservation, ecology and economic assessment
Publisher: Springer Science and Business Media LLC
Date: 11-2019
DOI: 10.1038/S41598-019-52250-1
Abstract: Deep-sea sponge grounds are vulnerable marine ecosystems, which through their benthic-pelagic coupling of nutrients, are of functional relevance to the deep-sea realm. The impact of fishing bycatch is here evaluated for the first time at a bathyal, sponge-dominated ecosystem in the high seas managed by the Northwest Atlantic Fisheries Organization. Sponge biomass surface created from research survey data using random forest modeling revealed 231,136 t of sponges in the area. About 42% of that biomass was protected by current fisheries closures. However, projections of trawling tracks estimated that the sponge biomass within them would be wiped out in just 1 year by the current level of fishing activity if directed on the sponges. Because these sponges filter 56,143 ± 15,047 million litres of seawater daily, consume 63.11 ± 11.83 t of organic carbon through respiration, and affect the turnover of several nitrogen nutrients, their removal would likely affect the delicate ecological equilibrium of the deep-sea benthic ecosystem. We estimated that, on Flemish Cap, the economic value associated with seawater filtration by the sponges is nearly double the market value of the fish catch. Hence, fishery closures are essential to reach sponge conservation goals as economic drivers cannot be relied upon.
Biodiversity, environmental drivers, and sustainability of the global deep-sea sponge microbiome
Publisher: Springer Science and Business Media LLC
Date: 02-09-2022
DOI: 10.1038/S41467-022-32684-4
Abstract: In the deep ocean symbioses between microbes and invertebrates are emerging as key drivers of ecosystem health and services. We present a large-scale analysis of microbial ersity in deep-sea sponges (Porifera) from scales of sponge in iduals to ocean basins, covering 52 locations, 1077 host in iduals translating into 169 sponge species (including understudied glass sponges), and 469 reference s les, collected anew during 21 ship-based expeditions. We demonstrate the impacts of the sponge microbial abundance status, geographic distance, sponge phylogeny, and the physical-biogeochemical environment as drivers of microbiome composition, in descending order of relevance. Our study further discloses that fundamental concepts of sponge microbiology apply robustly to sponges from the deep-sea across distances of ,000 km. Deep-sea sponge microbiomes are less complex, yet more heterogeneous, than their shallow-water counterparts. Our analysis underscores the uniqueness of each deep-sea sponge ground based on which we provide critical knowledge for conservation of these vulnerable ecosystems.
Ecological and genetic evidence for impaired sexual reproduction and induced clonality in the hydroid Sertularia cupressina (Cnidaria: Hydrozoa) on commercial scallop grounds in Atlantic Canada
Publisher: Springer Science and Business Media LLC
Date: 25-06-2004
Kernel Density Surface Modelling as a Means to Identify Significant Concentrations of Vulnerable Marine Ecosystem Indicators
Publisher: Public Library of Science (PLoS)
Date: 07-10-2014
Genome-wide DNA methylation predicts environmentally driven life history variation in a marine fish
Publisher: Oxford University Press (OUP)
Date: 08-12-2022
Abstract: Epigenetic modifications are thought to be one of the molecular mechanisms involved in plastic adaptive responses to environmental variation. However, studies reporting associations between genome-wide epigenetic changes and habitat-specific variations in life history traits (e.g., lifespan, reproduction) are still scarce, likely due to the recent application of methylome resequencing methods to non-model species. In this study, we examined associations between whole genome DNA methylation and environmentally driven life history variation in 2 lineages of a marine fish, the capelin (Mallotus villosus), from North America and Europe. In both lineages, capelin harbor 2 contrasting life history tactics (demersal vs. beach-spawning). Performing whole genome and methylome sequencing, we showed that life history tactics are associated with epigenetic changes in both lineages, though the effect was stronger in European capelin. Genetic differentiation between the capelin harboring different life history tactics was negligible, but we found genome-wide methylation changes in both lineages. We identified 9,125 European and 199 North American differentially methylated regions (DMRs) due to life history. Gene ontology (GO) enrichment analysis for both lineages revealed an excess of terms related to neural function. Our results suggest that environmental variation causes important epigenetic changes that are associated with contrasting life history tactics in lineages with ergent genetic backgrounds, with variable importance of genetic variation in driving epigenetic variation. Our study emphasizes the potential role of genome-wide epigenetic variation in adaptation to environmental variation.
Barcoding Atlantic Canada's commonly encountered marine fishes
Publisher: Wiley
Date: 17-12-2012
Abstract: Marine fishes from the northwest Atlantic Ocean were analysed to determine whether barcoding was effective at identifying species. Our data included 177 species, 136 genera, 81 families and 28 orders. Overall, 88% of nominal species formed monophyletic clusters based on >500 bp of the CO1 region, and the average bootstrap value for these species was 98%. Although clearly effective, the percentage of species that were distinguishable with barcoding based on the criterion of reciprocal monophyletic clusters was slightly lower than has been documented in other studies of marine fishes. Eelpouts, sculpins and rocklings proved to be among the most challenging groups for barcoding, although we suspect that difficult identifications based on traditional (morphology based) taxonomy played a role. Within several taxa, speciation may have occurred too recently for barcoding to be effective (e.g. within Sebastes, Thunnus and Ammodytes) or the designation of distinct species may have been erroneous (e.g. within Antimora and Macrourus). Results were consistent with previous work recognizing particularly high levels of ergence within certain taxa, some of which have been recognized as distinct species (e.g. Osmerus mordax and Osmerus dentex and Liparis gibbus and Liparis bathyarcticus), and some of which have not (e.g. within Halargyreus johnsonii and within Mallotus villosus). The results from this study suggest that morphology-based identification and taxonomy can be challenging in marine fishes, even within a region as well characterized as Atlantic Canada. Barcoding proved to be a very useful tool for species identification that will likely find a wide range of applications, including the fisheries trade, studies of range expansion, ecological analyses and population assessments.
Constraints on Alpine Fault (New Zealand) Mylonitization Temperatures and Geothermal Gradient from Ti-in-quartz Thermobarometry
Publisher: Copernicus GmbH
Date: 07-03-2018
DOI: 10.5194/SE-2018-12
Abstract: Abstract. We constrain the thermal state of the central Alpine Fault using approximately 750 Ti-in-quartz SIMS analyses from a suite of variably deformed mylonites. Ti-in-quartz concentrations span more than an order of magnitude from 0.24 to ~5 ppm, suggesting recrystallization of quartz over a 300° range in temperature. Most Ti-in-quartz concentrations in mylonites, protomylonites, and the Alpine Schist protolith are between 2 and 4 ppm and do not vary as a function of grain size or bulk rock composition. Analyses of 30 large, inferred-remnant quartz grains ( µm), as well as late, cross-cutting, chlorite-bearing quartz veins also reveal restricted Ti concentrations of 2–4 ppm. These results indicate that the vast majority of Alpine Fault mylonitization occurred within a restricted zone of pressure-temperature conditions where 2–4 ppm Ti-in-quartz concentrations are stable. This constrains the deep geothermal gradient from the moho to about 8 km to a slope of 5 °/km. In contrast, the small grains (10–40 µm) in ultramylonites have lower Ti concentrations of 1–2 ppm, indicating a deviation from the deeper pressure-temperature trajectory during the latest phase of ductile deformation. These constraints suggest an abrupt, order of magnitude change in the geothermal gradient to an average of about 60 °/km at depths shallower than about 8 km, i.e. within the seismogenic zone. Anomalously, the lowest-Ti quartz (0.24–0.7 ppm) occurs away from the fault in protomylonites, suggesting that the outer fault zone experienced minor plastic deformation late in the exhumation history when more fault-proximal parts of the fault were deforming exclusively by brittle processes.
Petrophysical, Geochemical, and Hydrological Evidence for Extensive Fracture-Mediated Fluid and Heat Transport in the Alpine Fault's Hanging-Wall Damage Zone
Publisher: American Geophysical Union (AGU)
Date: 12-2017
DOI: 10.1002/2017GC007202
North Atlantic Basin-Scale Multi-Criteria Assessment Database to Inform Effective Management and Protection of Vulnerable Marine Ecosystems
Publisher: Frontiers Media SA
Date: 23-03-2021
Isolation and characterization of 26 novel microsatellite loci in the deep-sea shrimp Acanthephyra pelagica
Publisher: Springer Science and Business Media LLC
Date: 18-04-2014
Differential processing of dissolved and particulate organic matter by deep-sea sponges and their microbial symbionts
Publisher: Springer Science and Business Media LLC
Date: 15-10-2020
DOI: 10.1038/S41598-020-74670-0
Abstract: Deep-sea sponges create hotspots of bio ersity and biological activity in the otherwise barren deep-sea. However, it remains elusive how sponge hosts and their microbial symbionts acquire and process food in these food-limited environments. Therefore, we traced the processing (i.e. assimilation and respiration) of 13 C- and 15 N-enriched dissolved organic matter (DOM) and bacteria by three dominant North Atlantic deep-sea sponges: the high microbial abundance (HMA) demosponge Geodia barretti , the low microbial abundance (LMA) demosponge Hymedesmia paupertas , and the LMA hexactinellid Vazella pourtalesii . We also assessed the assimilation of both food sources into sponge- and bacteria-specific phospholipid-derived fatty acid (PLFA) biomarkers. All sponges were capable of assimilating DOM as well as bacteria. However, processing of the two food sources differed considerably between the tested species: the DOM assimilation-to-respiration efficiency was highest for the HMA sponge, yet uptake rates were 4–5 times lower compared to LMA sponges. In contrast, bacteria were assimilated most efficiently and at the highest rate by the hexactinellid compared to the demosponges. Our results indicate that phylogeny and functional traits (e.g., abundance of microbial symbionts, morphology) influence food preferences and diet composition of sponges, which further helps to understand their role as key ecosystem engineers of deep-sea habitats.
Trait-based approach on deep-sea corals in the high-seas of the Flemish Cap and Flemish Pass (northwest Atlantic)
Publisher: PeerJ
Date: 14-03-2018
DOI: 10.7287/PEERJ.PREPRINTS.26698V1
Abstract: Deep-sea coral aggregations represent important ecosystems in the Flemish Cap, where some areas have been closed to bottom fisheries by the Northwest Atlantic Fisheries Organization in order to implement conservation and management measures and prevent significant adverse impacts on Vulnerable Marine Ecosystems (VMEs). Flemish Cap is an offshore Bank located about 600 km to the east of Newfoundland, separated from the Grand Banks by the Flemish Pass, a channel approximately 1200 m deep. 40 taxa of corals were identified in the area from bottom trawl research vessel surveys (2006-2015) and rock dredges (2009-2010). They included 22 Alcyonacea, 11 Pennatulacea, 3 Antipatharia and 4 Scleractinia. Corals identified were classified according to their biological traits in an attempt to better understand their function in the ecosystem. This study analyzes which biological traits were useful to classify corals in the Flemish Cap and Flemish Pass prioritizing traits where information is available and that capture variation for a range of biological or ecological processes. This study represents a baseline classification, quantifying trait variation among species, for further studies such as habitat suitability models or impact studies from trawl fisheries and oil and gas exploitation, which represent the main potential human activities in the area.
Morphometrics of American Lobster (Homarus americanus) Larvae in Relation to Stock Determinations in the Maritimes, Canada
Publisher: Canadian Science Publishing
Date: 1993
DOI: 10.1139/F93-005
Abstract: Morphological characteristics of the first larval stage of the American lobster (Homarus americanus) enabled the separation of the Maritime population with stepwise discriminant function analysis into three groups: the southern Gulf of St. Lawrence and its outflow around Cape Breton Island, the Atlantic inshore region of Nova Scotia, and the offshore banks bordering the Gulf of Maine. Once the effect of environmental temperature on larval size was removed, the differences between Georges and Browns banks and the Atlantic inshore disappeared. The remaining differences, chiefly in the dimensions of the second and fifth abdominal segments and the rostrum, between larvae from the Cape Breton sites and elsewhere may be due to other environmental factors or partial genetic isolation. Conservation and management practices over the past century have increased gene flow between regions, and most of this appears to be from the release of Gulf of St. Lawrence lobsters in the Gulf of Maine. A reassessment of previous studies on adult morphology, benthic movements, larval dispersal, enzyme electrophoresis, and commercial landing patterns supports the separation of the Gulf of St. Lawrence stock from the rest of the Canadian Maritimes.
Degree of Selective Constraint as an Explanation of the Different Rates of Evolution of Gender-Specific Mitochondrial DNA Lineages in the Mussel Mytilus
Publisher: Oxford University Press (OUP)
Date: 07-1996
DOI: 10.1093/GENETICS/143.3.1349
Abstract: Mussels of the genus Mytilus segregate for a maternally transmitted F lineage and a paternally transmitted M lineage of mitochondrial DNA. Previous studies demonstrated that these lineages are older than the species of the M. edulis complex and that the M lineage evolves faster than the F lineage. Here we show that the latter observation also applies to a region of the molecule with no assigned function. Sequence data for the mitochondrial COIII gene and the “unassigned” region of the F and M lineages of M. edulis and M. trossulus are used to evaluate various hypotheses that may account for the faster rate of evolution of the M lineage. Tests based on the proportion of synonymous and nonsynonymous substitutions suggest that the M lineage experiences relatively relaxed selection. Further support for this hypothesis comes from an examination of COIII amino acid substitutions at sites defined as either conserved or variable based on the pattern of variation in other mollusks and Drosophila. Most substitutions in the M lineage occur in regions that are also variable among non-Mytilus taxa. We suggest that these differences in selection pressure are a consequence of doubly uniparental mitochondrial DNA transmission in Mytilus.
Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand
Publisher: Informa UK Limited
Date: 02-10-2017
An eighteenth century commercial length-frequency sample of Atlantic cod, Gadus morhua, based on archaeological data
Publisher: Elsevier BV
Date: 12-1993
Genetic circumscription of deep-water coral species in Canada using 18S rRNA
Publisher: Springer Berlin Heidelberg
Date: 2005
<strong>Morphological and genetic variation in North Atlantic giant file clams, <em>Acesta</em> spp. (Bivalvia: Limidae), with description of a new cryptic species in the northwest A
Publisher: Magnolia Press
Date: 27-08-2015
DOI: 10.11646/ZOOTAXA.4007.2.1
Abstract: We analyze the morphological and genetic variability within and between seven species of Acesta and specimens recently collected in the northwest Atlantic using traditional morphological measurements, landmark-based geometric morphometrics, and the cytochrome oxidase subunit I (COI) gene sequences, with particular emphasis on North Atlantic species. Shell morphology and external shell appearance do not allow reliable distinction between the widely recognized northeastern Atlantic A. excavata and other northwest Atlantic species or populations of Acesta, with the exception of A. oophaga. Similarly, shape analysis reveals a wide variability within northeastern Atlantic A. excavata, and significant morphological overlap with A. bullisi from the Gulf of Mexico and A. rathbuni from the southwestern Pacific and South China Sea. Specimens from the northwestern and Mid-Atlantic display shell shapes marginally similar to that of A. excavata. These differences are at least partly related to anterior or posterior shifting of the shell body and to the opposite shifting of the hinge line/dorsal region and upper lunule. These morphological variations, along with the midline-width-ratio, explain much of the variability extracted by principal component analysis. Results from a mitochondrial DNA barcode approach (COI), however, suggest that the northwest Atlantic specimens belong to a new species for which we propose the name Acesta cryptadelphe sp. nov. Differences in larval shell sizes between northeastern and northwestern Atlantic specimens are consistent with this result.
A statistical morphological analysis and taxonomic revision of the genus Xiphophora (Fucaceae)
Publisher: Oxford University Press (OUP)
Date: 08-1989
Evaluation of benthic assemblage structure in the NAFO regulatory area with regard to the protection of VME
Publisher: Oxford University Press (OUP)
Date: 28-10-2015
Life in the Fast Lane: Modeling the Fate of Glass Sponge Larvae in the Gulf Stream
Publisher: Frontiers Media SA
Date: 04-10-2021
DOI: 10.3389/FMARS.2021.701218
Abstract: Effective conservation management of deep-sea sponges, including design of appropriate marine protected areas, requires an understanding of the connectivity between populations throughout a species’ distribution. We provide the first consideration of larval connectivity among deep-sea sponge populations along the southeastern coast of North America, illustrate the influence of the Gulf Stream on dispersal, and complement published distribution models by evaluating colonization potential. Connectivity among known populations of the hexactinellid sponge Vazella pourtalesii was simulated using a 3-D biophysical dispersal model throughout its distribution from Florida, United States to Nova Scotia, Canada. We found no exchange with an estimated pelagic larval duration of 2 weeks between populations north and south of Cape Hatteras, North Carolina at surface, mid-water and seabed release depths, irrespective of month of release or application of a horizontal diffusion constant specific to cross-Gulf Stream diffusivity. The population north of Cape Hatteras and south of Cape Cod was isolated. There was some evidence that Gulf Stream eddies formed near Cape Hatteras could travel to the northwest, connecting the populations in the two sub-regions, however that would require a much longer pelagic duration than what is currently known. More likely almost all larval settlement will be in the immediate area of the adults. At sub-regional scales, connectivity was found from the Strait of Florida through to the Blake Plateau, southeastern United States, with the latter area showing potential for recruitment from more than one source population. The influence of the Charleston Bump, a shallow feature rising from the Blake Plateau, was substantial. Particles seeded just north of the Bump were transported greater distances than those seeded to the south, some of which were caught in an associated gyre, promoting retention at the seabed. To the north on the Scotian Shelf, despite weaker currents and greater distances between known occurrences, unidirectional transport was detected from Emerald Basin to the Northeast Channel between Georges and Browns Banks. These major conclusions remained consistent through simulations run with different averaging periods for the currents (decades to daily) and using two ocean model products (BNAM and GLORYS12V1).
SPATIAL VARIATION PATTERNS IN THE MARINE MACROALGA XIPHOPHORA GLADIATA SSP. GLADIATA (PHAEOPHYTA). I. PARTITIONING OF MORPHOLOGICAL CARIATION INTO SPATIAL SCALES1
Publisher: Wiley
Date: 09-1990
Mapping benthic ecological diversity and interactions with bottom-contact fishing on the Flemish Cap (northwest Atlantic)
Publisher: Elsevier BV
Date: 05-2020
Constraining Ice Shelf Anisotropy Using Shear Wave Splitting Measurements from Active‐Source Borehole Seismics
Publisher: American Geophysical Union (AGU)
Date: 09-2020
DOI: 10.1029/2020JF005707
Abstract: Observations of ice shelf anisotropy on borehole seismic data are presented. Hot‐water‐drilledboreholes were made by the Aotearoa New Zealand Ross Ice Shelf Programme through a grounding‐line proximal site at Windless Bight and the central Ross Ice Shelf site HWD‐2. The boreholes were used to freeze seismometers into the ice at different depths. Seismic observations of shear wave splitting were made on the borehole seismometers using active sources deployed at the surface. These shear wave splitting data were used to constrain anisotropic ice crystallographic preferred orientations (CPO) within the ice column. Forward models of seismic properties from different CPO geometries are compared to the observations and a best fitting CPO model is found to explain the seismic anisotropy at HWD‐2. This model consists of a vertical girdle of ice c axes that constitute 80% of the CPO in combination with tight horizontal clusters, which contribute 20% of ice c axes. The origin of the modeled CPO is discussed with regard to calculated strain rates at the site and found to be indicative of the current shear kinematics with vertical shear plane and horizontal shear direction. At HWD‐2 the 370 m thick ice shelf is calculated to consist of at least 197 m of anisotropic ice.
Recent approaches to the taxonomy of the Gracilariaceae (Gracilariales, Rhodophyta) and the Gracilaria verrucosa problem
Publisher: Springer Science and Business Media LLC
Date: 09-1990
DOI: 10.1007/BF00040222
Accumulation of domoic acid by the sea scallop (Placopecten magellanicus) fed cultured cells of toxic Pseudo-nitzschia multiseries
Publisher: Canadian Science Publishing
Date: 04-1997
DOI: 10.1139/F96-333
Abstract: Sea scallops (Placopecten magellanicus) were fed Pseudo-nitzschia multiseries (formerly P. pungens f. multiseries, Nitzschia pungens f. multiseries) cells of high domoic acid (DA) content (4.0-6.7 pg DA cdot cell -1 ) for 22 days, followed by 14 days of feeding with nontoxic microalgae. DA was incorporated within 24 h by the scallops, with increased uptake after 6 days, and was concentrated in tissues in the following order: digestive gland remaining soft tissue adductor muscle. A maximum DA concentration of 3108 mu g cdot g -1 was recorded in the digestive gland, approximately 150 times the regulatory limit (20 mu g DA cdot g -1 ) and among the highest levels observed in bivalve molluscs however, only trace amounts, 0.7-1.5 mu g cdot g -1 , were found concomitantly in the adductor muscle. At the end of the exposure period, 50.9% of the DA that had been supplied to the scallops had been incorporated into the tissues. Concentrations in the digestive gland 14 days after termination of the toxic diet remained high, 752 mu g DA cdot g -1 . Throughout the experiment, there was no sign of illness or mortality attributable to high DA loading, although the destructive s ling of animals did not allow us to assess the effects of the toxin in the longer term.
The effects of fishing on species and genetic diversity.
Publisher: CABI Publishing
Date: 2003
Morphometry and growth of sea pen species from dense habitats in the Gulf of St. Lawrence, eastern Canada
Publisher: Informa UK Limited
Date: 15-02-2018
Publisher Correction: Biodiversity, environmental drivers, and sustainability of the global deep-sea sponge microbiome
Publisher: Springer Science and Business Media LLC
Date: 11-2022
The alphabet soup that protects cold-water corals in the North Atlantic
Publisher: Inter-Research Science Center
Date: 17-12-2009
DOI: 10.3354/MEPS08303
Predicted distribution of the glass sponge Vazella pourtalesi on the Scotian Shelf and its persistence in the face of climatic variability
Publisher: Public Library of Science (PLoS)
Date: 24-10-2018
Nucleotide Content Gradients in Maternally and Paternally Inherited Mitochondrial Genomes of the Mussel Mytilus
Publisher: Springer Science and Business Media LLC
Date: 13-07-2007
Increasing Knowledge of Biodiversity on the Orphan Seamount: A New Species of Tedania (Tedaniopsis) Dendy, 1924
Publisher: Frontiers Media SA
Date: 16-02-2021
DOI: 10.3389/FMARS.2021.612857
Abstract: 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 describe are the very peculiar external morphology which is tree-like with dichotomous branching—a morphology not previously described in this subgenus and the combination of spicules found: long styles, the typical tornotes of the subgenus and two sizes of onychaetes. Additional information is provided on other species of Tedaniopsis described from the Atlantic Ocean. Based on the characteristics reported, we propose a new species, Tedania ( Tedaniopsis ) rappi sp. nov. in honor of Prof. Hans Tore Rapp (1972–2020), University of Bergen, Norway, a renowned sponge taxonomist and coordinator of the Horizon 2020 SponGES project. The holotype of T. ( T. ) phacellina Topsent, 1912 from the Azores, the only other northern Atlantic species in the subgenus Tedaniopsis , was reviewed for comparison.
Multi-decadal changes in the megabenthos of the Bay of Fundy: The effects of fishing
Publisher: Elsevier BV
Date: 10-2007
3-D ocean particle tracking modeling reveals extensive vertical movement and downstream interdependence of closed areas in the northwest Atlantic
Publisher: Springer Science and Business Media LLC
Date: 08-12-2020
DOI: 10.1038/S41598-020-76617-X
Abstract: Novel 3-D passive particle tracking experiments were performed in the northwest Atlantic to elucidate connectivity among areas closed to protect vulnerable marine ecosystems. We examined (1) the degree of vertical movement of particles released at different depths and locations (2) the location of potential source populations for the deep-sea taxa protected by the closures and (3) the degree of functional connectivity. A long-term oceanographic dataset (EN4) was queried to characterize the temperature and salinity regimes in each of the closed areas as a basis for interpreting recently published climate change projections. Using the Parcels Lagrangian particle tracking framework and the BNAM hydrodynamic model, we found enhanced connectivity over previously developed 2-D models and unexpected, current-driven, strong (to a maximum of about 1340 m) downward displacement at depth (450, 1000 and 2250 m), with weaker upward displacement except for the release depth of 2250 m which showed upward movement of 955 m with a drift duration of 3 months. The current velocities create down-stream interdependence among closed areas and allow redundancy to develop in some of the areas of the network, with some of the larger areas also showing retention. Source populations for sponges in the upstream closure are likely in adjacent waters of the Canadian continental shelf. Collectively this information can be used to inform management decisions related to the size and placement of these closed areas, and vertical velocity surfaces have potential for use in species distribution modeling of benthic species and habitats.
Towards a common approach to the assessment of the environmental status of deep-sea ecosystems in areas beyond national jurisdiction
Publisher: Elsevier BV
Date: 11-2020
New Scientific Information Can Help to Inform the Evaluation of EU Deep-sea Fisheries Regulations
Publisher: Brill
Date: 25-10-2021
DOI: 10.1163/15718085-BJA10074
Abstract: The European Union’s deep-sea fisheries regulations (Regulation (EU) No. 2016/2336) established obligations to manage deep-sea fisheries and to protect vulnerable marine ecosystems ( VME s). The European Commission is scheduled to complete a review of the regulations in 2021, providing an opportunity for new scientific information to be incorporated into the implementation of the regulations. Here, we summarise research outputs from the EU-funded Horizon 2020 ATLAS Project and explain their relevance to the regulation of deep-sea fisheries in EU waters. ATLAS research has increased our understanding of the distribution of VME s and their importance in terms of ecosystem functioning. ATLAS research has also highlighted the utility of molecular techniques to understand fish population structure and the potential for habitat suitability models to help incorporate climate change into decision-making. Building on these scientific advances, we provide recommendations to help increase the effectiveness of management measures to conserve deep-sea fish stocks and protect VME s.
DNA barcoding of Canada’s skates
Publisher: Wiley
Date: 09-06-2011
DOI: 10.1111/J.1755-0998.2011.03034.X
Abstract: DNA-based identifications have been employed across broad taxonomic ranges and provide an especially useful tool in cases where external identification may be problematic. This study explored the utility of DNA barcoding in resolving skate species found in Atlantic Canadian waters. Most species were clearly resolved, expanding the utility for such identification on a taxonomically problematic group. Notably, one genus (Amblyraja) contained three of four species whose distributions do not overlap that could not be readily identified with this method. On the other hand, two common and partially sympatric species (Little and Winter skates) were readily identifiable. There were several instances of inconsistency between the voucher identification and the DNA sequence data. In some cases, these were at the intrageneric level among species acknowledged to be prone to misidentification. However, several instances of intergeneric discrepancies were also identified, suggesting either evidence of past introgressive hybridization or misidentification of vouchered specimens across broader taxonomic ranges. Such occurrences highlight the importance of retaining vouchered specimens for subsequent re-examination in the light of conflicting DNA evidence.
Genetics of Mother-Dependent Sex Ratio in Blue Mussels (Mytilus spp.) and Implications for Doubly Uniparental Inheritance of Mitochondrial DNA
Publisher: Oxford University Press (OUP)
Date: 08-2002
DOI: 10.1093/GENETICS/161.4.1579
Abstract: Previous studies have shown that in most pair matings of Mytilus edulis, M. trossulus, and M. galloprovincialis there is a large sex-ratio bias in favor of either males or females. The degree of bias is a characteristic property of the female parent, as matings of the same female with different males produce the same sex ratio, but matings of the same male with different females produce different sex ratios. All three species possess the unusual feature of doubly uniparental inheritance of mitochondrial DNA (mtDNA) i.e., they contain two distinct types of mtDNA, one that is transmitted matrilinearly and one that is transmitted patrilinearly. This coupling of sex and mtDNA transmission raises the possibility that the mechanism of sex-ratio determination in mussels might be under the control of the mtDNA of the female parent. Here we present data from pedigreed crosses that confirm the previous observations that in mussel matings there is a strong sex-ratio bias and that the bias is under the control of the female parent. In addition, these data strongly suggest that this control is exercised by the mother's nuclear rather than mitochondrial genotype. Making use of these findings we develop a model of mother-dependent sex determination and use data from crosses involving wild females to test the model's predictions at the population level.
Climate change winner in the deep sea? Predicting the impacts of climate change on the distribution of the glass sponge Vazella pourtalesii
Publisher: Inter-Research Science Center
Date: 07-01-2021
DOI: 10.3354/MEPS13566
Abstract: Shallow-water sponges are often cited as being ‘climate change winners’ due to their resiliency against climate change effects compared to other benthic taxa. However, little is known of the impacts of climate change on deep-water sponges. The deep-water glass sponge Vazella pourtalesii is distributed off eastern North America, forming dense sponge grounds with enhanced bio ersity on the Scotian Shelf off Nova Scotia, Canada. While the strong natural environmental variability that characterizes these sponge grounds suggests this species is resilient to a changing environment, its physiological limitations remain unknown, and the impact of more persistent anthropogenic climate change on its distribution has never been assessed. We used Random Forest and generalized additive models to project the distribution of V. pourtalesii in the northwest Atlantic using environmental conditions simulated under moderate and worst-case CO 2 emission scenarios. Under future (2046-2065) climate change, the suitable habitat of V. pourtalesii will increase up to 4 times its present-day size and shift into deeper waters and higher latitudes, particularly in its northern range where ocean warming will serve to improve the habitat surrounding this originally sub-tropical species. However, not all areas projected as suitable habitat in the future will realistically be populated, and the reduced likelihood of occurrence in its core habitat on the Scotian Shelf suggests that the existing Vazella sponge grounds may be negatively impacted. An effective monitoring programme will require tracking changes in the density and distribution of V. pourtalesii at the margins between core habitat and where losses and gains were projected.
Fourier Analysis of Sea Scallop (Placopecten magellanicus) Shells in Determining Population Structure
Publisher: Canadian Science Publishing
Date: 02-1994
DOI: 10.1139/F94-035
Abstract: Sea scallops (Placopecten magellanicus) were s led from each of four scallop beds: the northeast peak of Georges Bank, Western Bank, St. Pierre Bank, and the Bay of Fundy near Digby, N.S. The outlines of scallop top shells were captured by video imagery using a semiautomated approach. Fourier shape descriptors were calculated and analyzed. Age and year-class effects were shown to be important factors influencing scallop shell shape. Allometric effects on Fourier harmonics also have a significant influence on shell shape in this species. Comparisons of Fourier harmonics between scallop beds separated by age and s ling year, and corrected for allometry, revealed significant differences in the majority of harmonic numbers. Post hoc analyses identified St. Pierre Bank and the Bay of Fundy as being significantly different from the other beds in a suite of separate analyses.
Microbial Strategies for Survival in the Glass Sponge Vazella pourtalesii
Publisher: American Society for Microbiology
Date: 25-08-2020
DOI: 10.1128/MSYSTEMS.00473-20
Abstract: We investigated the microbial community of V. pourtalesii that forms globally unique, monospecific sponge grounds under low-oxygen conditions on the Scotian Shelf, where it plays a key role in its vulnerable ecosystem. The microbial community was found to be concentrated within biomass patches and is dominated by small cells ( μm). MAG analyses showed consistently small genome sizes and low GC contents, which is unusual compared to known sponge symbionts. These properties, as well as the (facultatively) anaerobic metabolism and a high degree of interdependence between the dominant symbionts regarding amino acid and vitamin synthesis, are likely adaptations to the unique conditions within the syncytial tissue of their hexactinellid host and the low-oxygen environment.
Assessing the environmental status of selected North Atlantic deep-sea ecosystems
Publisher: Elsevier BV
Date: 12-2020
The 18S rRNA gene sequences of four commercially important seaweeds
Publisher: Springer Science and Business Media LLC
Date: 12-1992
DOI: 10.1007/BF02185796
Reproductive biology of the deep-water coral Acanella arbuscula (Phylum Cnidaria: Class Anthozoa: Order Alcyonacea), northwest Atlantic
Publisher: Elsevier BV
Date: 10-2012
Net productivity of two cohorts of Chordaria flagelliformis (Phaeophyta) in Nova Scotia, Canada
Publisher: Springer Science and Business Media LLC
Date: 1982
DOI: 10.1007/BF00396998
Segregation of sperm mitochondria in two- and four-cell embryos of the blue musselMytilus edulis: implications for the mechanism of doubly uniparental inheritance of mitochondrial DNA
Publisher: Canadian Science Publishing
Date: 07-2006
DOI: 10.1139/G06-036
Abstract: Species of the family Mytilidae have 2 mitochondrial genomes, one that is transmitted through the egg and one that is transmitted through the sperm. In the Mytilus edulis species complex (M. edulis, M. galloprovincialis, and M. trossulus) there is also a strong mother-dependent sex-ratio bias in favor of one or the other sex among progeny from pair matings. In a previous study, we have shown that sperm mitochondria enter the egg and that their behavior during cell ision is different depending on whether the egg originated from a female- or male-biased mother. Specifically, in eggs from females that produce mostly or exclusively daughters, sperm mitochondria disperse randomly among cells after egg ision. In eggs from females that produce predominantly sons, sperm mitochondria tend to stay together in the same cell. Here, we extend these observations and show that in 2- and 4-cell embryos from male-biased mothers most sperm mitochondria are located near or at the cleavage furrow of the major cell, in contrast to embryos from female-biased mothers where there is no preferential association of sperm mitochondria with the cleavage furrow. This observation provides evidence for an early developmental mechanism through which sperm mitochondria are preferentially channeled into the primordial cells of male embryos, thus making the paternal mitochondrial genome the dominant mtDNA component of the male germ line.Key words: mussels, doubly uniparental inheritance of mtDNA, sperm mitochondria.
Genetic relationships among subpopulations of the American lobster (Homarus americanus) as revealed by random amplified polymorphic DNA
Publisher: Canadian Science Publishing
Date: 08-1997
DOI: 10.1139/F97-082
Abstract: Random lified polymorphic DNA (RAPD) profiles were used in a preliminary investigation of the genetic relationships among American lobsters (Homarus americanus) from the ecologically disparate and geographically separate regions of the southern Gulf of St. Lawrence, a bay off southwestern Nova Scotia, and a deep-sea canyon off Georges Bank. Phenotypic analyses of the RAPD bands showed no significant difference between s les caught at these three geographic locations. Lobsters from the Gulf of Maine, collected inshore from Lobster Bay, Nova Scotia, and offshore from Georges Bank, were genetically the most similar (D = 0.002), whereas Gulf of St. Lawrence lobsters were about three times as genetically distant from these two subpopulations (D = 0.005-0.006). However, F ST values at each RAPD band ranged from .000 to 0.073, indicating that lobsters at these three locations are not genetically isolated. The number of migrants needed to account for this observed level of genetic differentiation could be as few as five animals in each generation. The present findings should not have been surprising given the enormous potential for larval dispersal, the wide ranging movements of adult lobsters within each region, and the level of anthropogenic interference through both displacement of larvae and adults over the past century in the name of conservation, particularly adults released into the Gulf of Maine.
Intraspecific geographic-morphological variation patterns in Fucus distichus and F. evanescens
Publisher: Springer Science and Business Media LLC
Date: 1985
DOI: 10.1007/BF00397168
Ancient deep-sea sponge grounds on the Flemish Cap and Grand Bank, northwest Atlantic
Publisher: Springer Science and Business Media LLC
Date: 29-02-2016
Phylogenetic Diversity of the Cold Water Octocoral Paragorgia arborea (Linnaeus, 1758) off the East Coast of Canada
Publisher: Canadian Center of Science and Education
Date: 20-12-2010
DOI: 10.5539/IJB.V3N1P3
Demographics and landscape features determine intrariver population structure in Atlantic salmon (Salmo salar L.): the case of the River Moy in Ireland
Publisher: Wiley
Date: 11-2008
The BenBioDen database, a global database for meio-, macro- and megabenthic biomass and densities
Publisher: Springer Science and Business Media LLC
Date: 29-06-2020
DOI: 10.1038/S41597-020-0551-2
Abstract: Benthic fauna refers to all fauna that live in or on the seafloor, which researchers typically ide into size classes meiobenthos (32/64 µm–0.5/1 mm), macrobenthos (250 µm–1 cm), and megabenthos ( cm). Benthic fauna play important roles in bioturbation activity, mineralization of organic matter, and in marine food webs. Evaluating their role in these ecosystem functions requires knowledge of their global distribution and biomass. We therefore established the BenBioDen database, the largest open-access database for marine benthic biomass and density data compiled so far. In total, it includes 11,792 georeferenced benthic biomass and 51,559 benthic density records from 384 and 600 studies, respectively. We selected all references following the procedure for systematic reviews and meta-analyses, and report biomass records as grams of wet mass, dry mass, or ash-free dry mass, or carbon per m 2 and as abundance records as in iduals per m 2 . This database provides a point of reference for future studies on the distribution and biomass of benthic fauna.
Sex‐specific effects of hybridization on reproductive fitness inMytilus
Publisher: Hindawi Limited
Date: 22-11-2019
DOI: 10.1111/JZS.12348
Oceanographic setting influences the prokaryotic community and metabolome in deep-sea sponges
Publisher: Springer Science and Business Media LLC
Date: 03-2022
DOI: 10.1038/S41598-022-07292-3
Abstract: 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 licon sequencing and untargeted metabolomics, we assessed prokaryotic and chemical ersities in three deep-sea sponge species: Geodia barretti , Stryphnus fortis , and Weberella 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 ( licon sequence variants) showed significant changes with depth while phylum-level composition of host microbiome remained unchanged. The metabolome varied with depth, with relative quantities of known bioactive compounds increasing or decreasing strongly. Other metabolites varying with depth were compatible solutes regulating osmolarity of the cells. Correlations between prokaryotic community and the bioactive compounds in G. barretti suggested members of Acidobacteria, Proteobacteria, Chloroflexi, or an unclassified prokaryote as potential producers.
Systematic Conservation Planning at an Ocean Basin Scale: Identifying a Viable Network of Deep-Sea Protected Areas in the North Atlantic and the Mediterranean
Publisher: Frontiers Media SA
Date: 30-06-2021
DOI: 10.3389/FMARS.2021.611358
Abstract: Designing conservation networks requires a well-structured framework for achieving essential objectives such as connectivity, replication or viability, and for considering local management and socioeconomic stakes. Although systematic conservation planning (SCP) approaches are increasingly used to inform such networks, their application remains challenging in large and poorly researched areas. This is especially the case in the deep sea, where SCP has rarely been applied, although growing awareness of the vulnerability of deep-sea ecosystems urges the implementation of conservation measures from local to international levels. This study aims to structure and evaluate a framework for SCP applicable to the deep sea, focusing on the identification of conservation priority networks for vulnerable marine ecosystems (VMEs), such as cold-water coral reefs, sponge grounds, or hydrothermal vents, and for key demersal fish species. Based on multi-objective prioritization, different conservation scenarios were investigated, allowing the impact of key elements such as connectivity and conservation cost to be evaluated. Our results show that continental margin slopes, the Mid-Atlantic Ridge, and deeper areas of large and productive shelves housing fishing grounds appeared as crucial zones for preserving the deep-sea bio ersity of the North Atlantic, and within the limitations imposed by the data available, of the Mediterranean. Using biologically-informed connectivity led to a more continuous and denser conservation network, without increasing the network size. Even when minimizing the overlap with socioeconomic activities, the inclusion of exploited areas was necessary to fulfil conservation objectives. Such areas included continental shelf fishing grounds for demersal fish species, and areas covered by deep-sea mining exploration contracts for hydrothermal vent communities. Covering 17% of the study area and protecting 55% of each feature on average, the identified priority network held a high conservation potential. However, these areas still suffer from poor protection, with 30% of them benefiting from some form of recognition and 11% only from protection against trawling. Integrating them into current marine spatial planning (MSP) discussions could foster the implementation of a basin-scale conservation network for the deep sea. Overall, this work established a framework for developing large-scale systematic planning, useful for managing Areas Beyond National Jurisdiction (ABNJ).
Managing marine genetic diversity: time for action?
Publisher: Oxford University Press (OUP)
Date: 2003
Porosity evolution within the active Alpine Fault zone, New Zealand. Implications for fault zone rheology.
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-9399
Abstract: & & Feedback between deformation mechanisms, fluid-rock interactions and porosity evolution in fault zone rocks has a crucial impact on their bulk rheology. Porosity formation within mid-crustal fault rocks (typically mylonites) can facilitate fluid flow, formation of mineral and geothermal resources, and can promote strain localization. On the contrary, porosity reduction in rocks from a brittle fault core (typically cataclasites) can cause elevated pore fluid pressures, and consequently influence the recurrence time of earthquakes.& & & & We characterized the porosity distribution within the New Zealand& #8217 s Alpine Fault zone in cataclasite s les recovered during the first phase of the Deep Fault Drilling Project and outcropping mylonitic rocks collected at Stoney Creek, New Zealand. Synchrotron X-ray microtomography-derived analyses of open pore spaces show total microscale porosity values in the range of 0.1-0.24% within the cataclasites and up to 0.44% in the mylonites. Synchrotron nanotomography datasets reveal additional 0.03 to 0.19% pore volumes within the mylonites. In all s les, pores are very small, not connected, with mainly non-spherical, elongated, flat shapes and show subtle bipolar orientation. Scanning and transmission electron microscopy reveal the s les& #8217 microstructural organization, where nanoscale pores ornament grain boundaries of the constituent minerals. Pores are mostly associated with (often newly formed) clay minerals in the cataclasite s les, suggesting the orientation of clays controls the shape and orientation of the associated pores. In the mylonitic s les, pores are sub-parallel to the foliation, and often associated with C& #8217 -type shear bands, indicating formation during creep cavitation.& & & & Our observations imply that porosity within the Alpine Fault core was reduced due to pressure solution processes and the associated mineral precipitation. Simultaneously propagation of fluids triggered by cavity formation in the ductile regime is likely to cause further mineral precipitation in fluid filled pores within the fault zone. Such precipitation can affect the mechanical behavior of the Alpine Fault by decreasing the already critically low total porosity of the fault core, causing elevated pore fluid pressures, and/or introducing weak mineral phases, and thus lowering the overall fault frictional strength. We conclude that the current state of porosity in the Alpine Fault zone is likely to play a key role in the initiation of the next fault rupture.& &
MOLECULAR PHYLOGENY OF THREE OCTOPODID SPECIES FROM THE MEDITERRANEAN WATER, EGYPT
Publisher: Egypts Presidential Specialized Council for Education and Scientific Research
Date: 09-2006
Modeling the Distribution of Geodia Sponges and Sponge Grounds in the Northwest Atlantic
Publisher: Public Library of Science (PLoS)
Date: 04-12-2013
Should potential for climate change refugia be mainstreamed into the criteria for describing EBSAs?
Publisher: Wiley
Date: 11-02-2019
DOI: 10.1111/CONL.12634
The Control Region of Maternally and Paternally Inherited Mitochondrial Genomes of Three Species of the Sea Mussel Genus Mytilus
Publisher: Oxford University Press (OUP)
Date: 03-2009
DOI: 10.1534/GENETICS.108.093229
Abstract: Species of the mussel genus Mytilus possess maternally and paternally transmitted mitochondrial genomes. In the interbreeding taxa Mytilus edulis and M. galloprovincialis, several genomes of both types have been fully sequenced. The genome consists of the coding part (which, in addition to protein and RNA genes, contains several small noncoding sequences) and the main control region (CR), which in turn consists of three distinct parts: the first variable (VD1), the conserved (CD), and the second variable (VD2) domain. The maternal and paternal genomes are very similar in gene content and organization, even though they differ by & % in primary sequence. They differ even more at VD1 and VD2, yet they are remarkably similar at CD. The complete sequence of a genome from the closely related species M. trossulus was previously reported and found to consist of a maternal-like coding part and a paternal-like and a maternal-like CR. From this and from the fact that it was extracted from a male in idual, it was inferred that this is a genome that switched from maternal to paternal transmission. Here we provide clear evidence that this genome is the maternal genome of M. trossulus. We have found that in this genome the tRNAGln in the coding region is apparently defective and that an intact copy of this tRNA occurs in the CR, that one of the two conserved domains is missing essential motifs, and that one of the two first variable domains has a high rate of ergence. These features may explain the large size and mosaic structure of the CR of the maternal genome of M. trossulus. We have also obtained CR sequences of the maternal and paternal genomes of M. californianus, a more distantly related species. We compare the control regions from all three species, focusing on the ergence among genomes of different species origin and among genomes of different transmission routes.
Sponge assemblages and predicted archetypes in the eastern Canadian Arctic
Publisher: Inter-Research Science Center
Date: 11-06-2018
DOI: 10.3354/MEPS12589
Influence of seabird colonies and other environmental variables on benthic community structure, Lancaster Sound Region, Canadian Arctic
Publisher: Elsevier BV
Date: 03-2017
Glass sponge grounds on the Scotian Shelf and their associated biodiversity
Publisher: Inter-Research Science Center
Date: 04-04-2019
DOI: 10.3354/MEPS12903
Effects of experimental otter trawling on benthic assemblages on Western Bank, northwest Atlantic Ocean
Publisher: Elsevier BV
Date: 10-2006
Microbial diversity of the glass sponge Vazella pourtalesii in response to anthropogenic activities
Publisher: Springer Science and Business Media LLC
Date: 24-08-2020
DOI: 10.1007/S10592-020-01305-2
Abstract: Establishment of adequate conservation areas represents a challenging but crucial task in the conservation of genetic ersity and biological variability. Anthropogenic pressures on marine ecosystems and organisms are steadily increasing. Whether and to what extent these pressures influence marine genetic bio ersity is only starting to be revealed. Using 16S rRNA gene licon sequencing, we analysed the microbial community structure of 33 in iduals of the habitat-forming glass sponge Vazella pourtalesii , as well as reference seawater, sediment, and biofilm s les. 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 ersity on the Scotian Shelf, Canada. Our results illustrate that V. pourtalesii sponges collected from protected sites within fishery closures contained distinct and taxonomically largely novel microbial communities. At the trawled site we recorded significant quantitative differences in distinct microbial phyla, such as a reduction in Nitrospinae in the four sponges from this site and the environmental references. In iduals of V. pourtalesii growing on the mooring were significantly enriched in Bacteroidetes, Verrucomicrobia and Cyanobacteria in comparison to sponge in iduals growing on the natural seabed. Due to a concomitant enrichment of these taxa in the mooring biofilm, we propose that biofilms on artificial substrates may ‘prime’ sponge-associated microbial communities when small sponges settle on such substrates. These observations likely have relevant management implications when considering the increase of artificial substrates in the marine environment, e.g., marine litter, off-shore wind parks, and petroleum platforms.
A High‐Resolution 3‐D Circulation Model in a Complex Archipelago on the Coastal Scotian Shelf
Publisher: American Geophysical Union (AGU)
Date: 03-2022
DOI: 10.1029/2021JC017791
Abstract: A high‐resolution coastal Finite‐Volume Community Ocean Model (FVCOM) has been configured to simulate the water circulation in the Eastern Shore Islands (ESI) archipelago on the coastal Scotian Shelf. Circulation in this area is characterized by complex interactions between the irregular coastline, a dense archipelago, tides, wind, and subtidal currents. Model outputs show close agreement with the tides, subtidal current, and hydrographic observations. Two circulation regimes within the study area were identified “inshore” and “offshore” of the 60‐m isobath. The balance between pressure gradient and Coriolis effect controls the dominant southwestward current (Nova Scotia Current) in the offshore. Rotary spectra and numerical experiments showed that the tidal current was an important component to the circulation in the inshore. Within the study area there are several clockwise and counter‐clockwise gyres related to the Coriolis effect, surface wind stress, pressure gradient, and the interaction between the irregular topography and current. The combined effects of topography, wind, tide, and Nova Scotia Current regulate the inshore circulation. The topographic features complex the cross‐shore transport. The increased bathymetric slope and strengthened relative vorticity contribute to the inshore cross‐shore current. Here, we found that the joint effect of baroclinicity and bottom relief drives the cross‐isobath transport. The ability of our model to resolve complex coastal circulation patterns provides an important basis on which to better understand how physical oceanography influences the unique ecological processes of this coastal archipelago and ultimately will help to evaluate dispersal and connectivity of coastal species in this area.
Use of Biochemical Genetic Markers to Discriminate between Adductor Muscles of the Sea Scallop (Placopecten magellanicus) and the Iceland Scallop (Chlamys islandica)
Publisher: Canadian Science Publishing
Date: 06-1993
DOI: 10.1139/F93-138
Abstract: Three biochemical techniques were applied to adductor muscles of Placopecten magellanicus and Chlamys islandica, two commercially important scallops, to search for species-specific genetic markers. Allozyme electrophoresis identified two enzyme systems, mannose phosphate isomerase and glutamic oxaloacetate transaminase, which appear to be diagnostic. Sequencing of the 18S rRNA gene in each species showed 15 nucleotide differences over 1815 base pairs. Digestion of the gene with the restriction enzyme XHO I released two fragments in Placopecten and three in Chlamys. All three techniques could be developed for management purposes as part of an enforcement programme to identify illegally caught scallops.
Genetic Structure of Capelin (Mallotus villosus) in the Northwest Atlantic Ocean
Publisher: Public Library of Science (PLoS)
Date: 30-03-2015
Related Organisations
Bedford Institute Of Oceanography/Fisheries And Oceans, Canada
Location: Canada
Related Funding Activities
No related grants have been discovered for Ellen Kenchington.