Fe(III) (oxyhydr)oxide reduction by the thermophilic iron-reducing bacterium Desulfovulcanus ferrireducens

Some thermophilic bacteria from deep-sea hydrothermal vents grow by dissimilatory iron reduction, but our understanding of their biogenic mineral transformations is nascent. Mineral transformations catalyzed by the thermophilic iron-reducing bacterium Desulfovulcanus ferrireducens during growth at 55°C were examined using synthetic nanophase ferrihydrite, akaganeite, and lepidocrocite separately as terminal electron acceptors. Spectral analyses using visible-near infrared (VNIR), Fourier-transform infrared attenuated total reflectance (FTIR-ATR), and Mössbauer spectroscopies were complemented with x-ray diffraction (XRD) and transmission electron microscopy (TEM) using selected area electron diffraction (SAED) and energy dispersive X-ray (EDX) analyses. The most extensive biogenic mineral transformation occurred with ferrihydrite, which produced a magnetic, visibly dark mineral with spectral features matching cation-deficient magnetite. Desulfovulcanus ferrireducens also grew on akaganeite and lepidocrocite and produced non-magnetic, visibly dark minerals that were poorly soluble in the oxalate solution. Bioreduced mineral products from akaganeite and lepidocrocite reduction were almost entirely absorbed in the VNIR spectroscopy in contrast to both parent minerals and the abiotic controls. However, FTIR-ATR and Mössbauer spectra and XRD analyses of both biogenic minerals were almost identical to the parent and control minerals. The TEM of these biogenic minerals showed the presence of poorly crystalline iron nanospheres (50–200 nm in diameter) of unknown mineralogy that were likely coating the larger parent minerals and were absent from the controls. The study demonstrated that thermophilic bacteria transform different types of Fe(III) (oxyhydr)oxide minerals for growth with varying mineral products. These mineral products are likely formed through dissolution-reprecipitation reactions but are not easily predictable through chemical equilibrium reactions alone

Report of the ICES\NAFO Joint Working Group on Deep-water Ecology (WGDEC), 11–15 March 2013, Floedevigen, Norway.

On 11 February 2013, the joint ICES/NAFO WGDEC, chaired by Francis Neat (UK) and attended by ten members met at the Institute for Marine Research in Floedevi-gen, Norway to consider the terms of reference (ToR) listed in Section 2. WGDEC was requested to update all records of deep-water vulnerable marine eco-systems (VMEs) in the North Atlantic. New data from a range of sources including multibeam echosounder surveys, fisheries surveys, habitat modelling and seabed imagery surveys was provided. For several areas across the North Atlantic, WGDEC makes recommendations for areas to be closed to bottom fisheries for the purposes of conservation of VMEs

Squalus acanthias, spiny dogfish

While there are reported subpopulations of Squalus acanthias (Linnaeus, 1758) elsewhere in the world, the North Pacific subpopulation is now considered a separate species, Squalus suckleyi (Girard, 1854) (see Ebert et al. 2010). Further taxonomic studies on this genus are required, including in relation to Mediterranean and Black Sea subpopulations. In Europe, three subpopulations are inferred to occur.Fil: Finucci, B.. National Institute of Water and Atmospheric Research; Nueva ZelandaFil: Cheok, J.. University Fraser Simon; CanadáFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cotton, C. F.. Florida State University; Estados UnidosFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Kulka, D. W.. No especifíca; ArgentinaFil: Neat, F. C.. No especifíca; ArgentinaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Rigby, C. L.. James Cook University; AustraliaFil: Tanaka, S.. No especifíca; ArgentinaFil: Walker, T. I.. University of Melbourne; Australi

Connectivity in the Deep: Phylogeography of the Velvet Belly Lanternshark

PublishedThe velvet belly lanternshark, Etmopterus spinax, is a deep-sea bioluminescent squaloid shark, found predominantly in the northeast Atlantic and Mediterranean Sea. It has been exposed to relatively high levels of mortality associated with by-catch in some regions. Its late maturity and low fecundity potentially renders it vulnerable to over-exploitation, although little remains known about processes of connectivity between key habitats/regions. This study utilised DNA sequencing of partial regions of the mitochondrial control region and nuclear ribosomal internal transcribed spacer 2 to investigate population structure and phylogeography of this species across the northeast Atlantic and Mediterranean Basin. Despite the inclusion of samples from the range edges or remote locations, no evidence of significant population structure was detected. An important exception was identified using the control region sequence, with much greater (and statistically significant) levels of genetic differentiation between the Mediterranean and Atlantic. This suggests that the Strait of Gibraltar may represent an important bathymetric barrier, separating regions with very low levels of female dispersal. Bayesian estimation of divergence time also places the separation between the Mediterranean and Atlantic lineages within the last 100,000 years, presumably connected with perturbations during the last Glacial Period. These results demonstrate population subdivision at a much smaller geographic distance than has generally been identified in previous work on deep-sea sharks. This highlights a very significant role for shallow bathymetry in promoting genetic differentiation in deepwater taxa. It acts as an important exception to a general paradigm of marine species being connected by high levels of gene-flow, representing single stocks over large scales. It may also have significant implications for the fisheries management of this species.We would like to thank Trude Thangstad, Merete Kvalsund (Institute of Marine Research, Norway), Cecilia Pinto, Eleonora de Sabata and the scientists and crew of the RV Celtic Explorer for assistance in the collection of samples. Funding for this project was provided by the University of Salford and the University of Bristol. We are grateful to all those who helped with sample collection, including the MEDITS survey programme, the Department of Fisheries and Marine Research (DFMR) of Cyprus, the Annual Demersal and Deep Water Fish Monitoring Surveys financed by the Azores Government and the CONDOR project (supported by a grant from Iceland, Liechtenstein, Norway through the EEA Financial Mechanism (PT0040/2008)

A future for seafood point-of-origin testing using DNA and stable isotope signatures

Demand for seafood products is increasing worldwide, contributing to ever more complex supply chains and posing challenges to trace their origin and guarantee legal, well-managed, sustainable sources from confirmed locations. While DNA-based methods have proven to be reliable in verifying seafood authenticity at the species level, the verification of geographic origin remains inherently more complex. Both genetic and stable isotope analyses have been employed for determining point-of-origin with varying degrees of success, highlighting that their application can be effective when the right tool is selected for a given application. Developing an a priori prediction of their discrimination power for different applications can help avoid the financial cost of developing inappropriate reference datasets. Here, we reviewed the application of both techniques to seafood point-of-origin for 63 commercial finfish species certified by the Marine Stewardship Council, and showed that, even for those species where baseline data exist, real applications are scarce. To fill these gaps, we synthesised current knowledge on biological and biogeochemical mechanisms that underpin spatial variations in genetic and isotopic signatures. We describe which species’ biological and distribution traits are most helpful in predicting effectiveness of each tool. Building on this, we applied a mechanistic approach to predicting the potential for successful validation of origin to three case study fisheries, using combined genetic and isotopic methodologies to distinguish individuals from certified versus non-certified regions. Beyond ecolabelling applications, the framework we describe could be reproduced by governments and industries to select the most cost-effective techniques

A future for seafood point-of-origin testing using DNA and stable isotope signatures

Demand for seafood products is increasing worldwide, contributing to ever more complex supply chains and posing challenges to trace their origin and guarantee legal, well-managed, sustainable sources from confirmed locations. While DNA-based methods have proven to be reliable in verifying seafood authenticity at the species level, the verification of geographic origin remains inherently more complex. Both genetic and stable isotope analyses have been employed for determining point-of-origin with varying degrees of success, highlighting that their application can be effective when the right tool is selected for a given application. Developing an a priori prediction of their discrimination power for different applications can help avoid the financial cost of developing inappropriate reference datasets. Here, we reviewed the application of both techniques to seafood point-of-origin for 63 commercial finfish species certified by the Marine Stewardship Council, and showed that, even for those species where baseline data exist, real applications are scarce. To fill these gaps, we synthesised current knowledge on biological and biogeochemical mechanisms that underpin spatial variations in genetic and isotopic signatures. We describe which species’ biological and distribution traits are most helpful in predicting effectiveness of each tool. Building on this, we applied a mechanistic approach to predicting the potential for successful validation of origin to three case study fisheries, using combined genetic and isotopic methodologies to distinguish individuals from certified versus non-certified regions. Beyond ecolabelling applications, the framework we describe could be reproduced by governments and industries to select the most cost-effective techniques. Graphic abstract: [Figure not available: see fulltext.

Can ecosystem-based deep-sea fishing be sustained?

Can there ever be a truly sustainable deep-sea fishery and if so, where and under what conditions? Ecosystembased fisheries management requires that this question be addressed such that habitat, bycatch species, and targeted fish populations are considered together within an ecosystem context. To this end, we convened the first workshop to develop an ecosystem approach to deep-sea fisheries and to ask whether deep-sea species could be fished sustainably. The workshop participants were able to integrate bycatch information into their framework but found it more difficult to integrate other ecosystem indicators such as habitat characteristics. (First two paragraphs from the Executive Summary

A tale of two seas: contrasting patterns of population structure in the small-spotted catshark across Europe.

Elasmobranchs represent important components of marine ecosystems, but they can be vulnerable to overexploitation. This has driven investigations into the population genetic structure of large-bodied pelagic sharks, but relatively little is known of population structure in smaller demersal taxa, which are perhaps more representative of the biodiversity of the group. This study explores spatial population genetic structure of the small-spotted catshark (Scyliorhinus canicula), across European seas. The results show significant genetic differences among most of the Mediterranean sample collections, but no significant structure among Atlantic shelf areas. The data suggest the Mediterranean populations are likely to have persisted in a stable and structured environment during Pleistocene sea-level changes. Conversely, the Northeast Atlantic populations would have experienced major changes in habitat availability during glacial cycles, driving patterns of population reduction and expansion. The data also provide evidence of male-biased dispersal and female philopatry over large spatial scales, implying complex sex-determined differences in the behaviour of elasmobranchs. On the basis of this evidence, we suggest that patterns of connectivity are determined by trends of past habitat stability that provides opportunity for local adaptation in species exhibiting philopatric behaviour, implying that resilience of populations to fisheries and other stressors may differ across the range of species