32181 research outputs found
Sort by
New taxa and new synonymy in Muricidae (Neogastropoda: Pagodulinae, Trophoninae, Ocenebrinae) from the Northeast Pacific
Full text linkThe results of an extensive examination of northeast Pacific muricid gastropods ranging from Aleutian Islands, Alaska, to mid-Baja California, is presented. Two new genera and 26 new species are described: In Pagodulinae: Abyssotrophon fusiformis n. sp., A. newmani n. sp., Boreotrophon cascadiensis n. sp., B. cordellensis n. sp., B. cortesianus n. sp., B. obesus n. sp., B. subapolyonis n. sp., B. vancouverensis n. sp., B. aleuticus n. sp., B. pseudotripherus n. sp., B. santarosensis n. sp., B. tannerensis n. sp. In Trophoninae: Warenia, n. gen., Scabrotrophon buldirensis n. sp, S. kantori n. sp., S. lima n. sp., S. macleani n. sp., S. moresbyensis n. sp., S. norafosterae n. sp., S. trifidus n. sp., Nipponotrophon exquisitus n. sp. In Ocenebrinae: Paciocinebrina n. gen., Nucella angustior n. sp., Paciocinebrina benitoensis n. sp., P. macleani n. sp., P. neobarbarensis n. sp., P. pseudomunda n. sp., P. thelmacrowae n. sp. New synonymy: Boreotrophon kamchatkanus Dall, 1902 (+ Trophonopsis nanus Ergorov, 1994); Paciocinebrina atropurpurea (Carpenter, 1865) (+ Tritonalia interfossa var. clathrata Dall, 1919, Ocinebra rubra Baker, 1891, Tritonalia tracheia Dall, 1919); P. barbarensis (Gabb, 1865) (+ Tritonalia interfossa var. beta Dall, 1919, Ocenebra keenae Bormann, 1946); P. circumtexta (Stearns, 1871) (+ Ocinebra circumtexta var. aurantia Stearns, 1895, Tritonalia circumtexta var. citrica Dall, 1919, Tritonalia lurida var. rotunda Dall, 1919); P. foveolata (Hinds, 1844) (+Tritonalia epiphanea Dall, 1919, Tritonalia fusconotata Dall, 1919); P. gracillima (Stearns, 1871) (+ Tritonalia gracillima var. obesa Dall, 1919, Ocinebra stearnsi Hemphill, 1911); P. interfossa (Carpenter, 1864) (+ Tritonalia interfossa alpha Dall, 1921); P. lurida (Middendorff, 1848) (+ Vitularia aspera Baird, 1863), P. sclera (Dall, 1919) (+ Coralliophila (Pseudomurex) kincaidi Dall, 1919). Generic assignments are changed for the following taxa: Boreotrophon kamchatkanus Dall, 1902; Warenia elegantula (Dall, 1907); Scabrotrophon stuarti (E.A. Smith, 1880); Paciocinebrina atropurpurea (Carpenter, 1865), P. barbarensis (Gabb, 1865), P. circumtexta (Stearns, 1871), P. crispatissima (Berry, 1953), P. foveolata (Hinds, 1844), P. fraseri (Oldroyd, 1920), P. gracillima (Stearns, 1871), P. grippi (Dall, 1911), P. interfossa (Carpenter, 1864), P. lurida (Middendorff, 1848), P. minor (Dall, 1919), P. munda (Carpenter, 1864), P. seftoni (Chace, 1958), P. sclera (Dall, 1919). Boreotrophon alborostratus Taki, 1938, is reinstated. Abyssotrophon Egorov, 1993 and Nodulotrophon Habe & Ito, 1965 are here assigned to Pagodulinae Barco et al., 2012, based on radula morphology
3D subsurface characterisation of the Belgian Continental Shelf: a new voxel modelling approach
Full text linkModelling of surface and shallow subsurface data is getting more and more advanced and is demonstrated mostly for onshore (hydro)geological applications. Three-dimensional (3D) modelling techniques are used increasingly, and now include voxel modelling that often employs stochastic or probabilistic methods to assess model uncertainty. This paper presents an adapted method ologicalwork flow for the 3Dmodelling of offshore sand deposits and aims at demonstrating the improvement of the estimations of lithological properties after incorporation of more geological layers in the modelling process. Importantly, this process is driven by new geological insight from the combined interpretation of seismic and borehole data. Applying 3D modelling techniques is challenging given that offshore environments may be heavily reworked through time, often leading to thin and discontinuous deposits. Since voxel and stochastic modelling allow in-depth analyses of a multitude of properties (and their associated uncertainties) that define a lithological layer, they are ideal for use in an aggregate resource exploitation context. The voxel model is now the backbone of a decision support system for long-term sand extraction on the Belgian Continental Shelf
Understanding the biodiversity and evolutionary history of the amphipod genus <i>Eusirus</i> in the Southern Ocean
Full text linkLipid profile changes during the development of <i>Artemia franciscana</i>, from cysts to the first two naupliar stages
Full text linkThe brine shrimp Artemia is an interesting experimental system for studies of developmental processes. Hatching of dormant cysts gives rise to shrimp larvae called nauplii, characterized by numerous naupliar stages representing the first forms of brine shrimp life cycle. Here combined Thin Layer Chromatography (TLC) and Matrix-Assisted Laser Desorption Ionization-Time-of-Flight/Mass Spectrometry (MALDI-TOF/MS) analyses have been performed to gain information on the lipid profiles of cysts and two naupliar stages. Lipid bands isolated after preparative TLC of the lipid extracts have been analyzed to detect various species of each lipid class; in addition Post-Source Decay (PSD) analyses allowed the identification of phospholipid chains. We compared the relative abundance of various polar and neutral lipid species in the lipid extracts, proving for the first time that during the development of nauplii there is an increase of cardiolipin (CL) and lysophospholipid levels; in parallel, the amount of phosphatidylcholine (PC) decreases. In addition, as regards neutral lipids, we found an increase of diacylglycerols (DAGs) in correspondence of the decrease of triacylglycerols (TAGs). Data reflect the fact that naupliar stages, being an active form of life, are more metabolically active and offer a platform to develop further studies on the importance of lipid metabolic pathways and bioactive lipids during the development
Transnational and Integrated Long-term Marine Exploitation Strategies (TILES): Final Report
Full text linkIdentification of ecosystem services in an artificial reef and quantification of coastal protection
Full text linkCryptic temporal changes in stock composition explain the decline of a flounder (<i>Platichthys</i> spp.) assemblage
Full text linkUnobserved diversity, such as undetected genetic structure or the presence of cryptic species, is of concern for the conservation and management of global biodiversity in the face of threatening anthropogenic processes. For instance, unobserved diversity can lead to overestimation of maximum sustainable yields and therefore to overharvesting of the more vulnerable stock components within unrecognized mixed‐stock fisheries. We used DNA from archival (otolith) samples to reconstruct the temporal (1976–2011) genetic makeup of two mixed‐stock flounder fisheries in the Åland Sea (AS) and the Gulf of Finland (GoF). Both fisheries have hitherto been managed as a single stock of European flounders (Platichthys flesus), but were recently revealed to target two closely related species: the pelagic‐spawning P. flesus and the newly described, demersal‐spawning P. solemdali. While the AS and GoF fisheries were assumed to consist exclusively of P. solemdali, P. flesus dominated the GoF flounder assemblage (87% of total) in 1983, had disappeared (0%) by 1993, and remained in low proportions (10%–11%) thereafter. In the AS, P. solemdali dominated throughout the sampling period (>70%), and P. flesus remained in very low proportions after 1983. The disappearance of P. flesus from the GoF coincides in time with a dramatic (~60%) decline in commercial landings and worsening environmental conditions in P. flesus’ northernmost spawning ground, the Eastern Gotland Basin, in the preceding 4–6 years. These results are compatible with the hypothesis that P. flesus in the GoF is a sink population relying on larval subsidies from southern spawning grounds and the cause of their disappearance is a cessation of larval supply. Our results highlight the importance of uncovering unobserved genetic diversity and studying spatiotemporal changes in the relative contribution of different stock components, as well as the underlying environmental causes, to manage marine resources in the age of rapid anthropogenic change
The transcriptome of the marine calanoid copepod <i>Temora longicornis</i> under heat stress and recovery
No full textUnderstanding the impacts of global change in zooplankton communities is crucial, as alterations in the zooplankton communities can affect entire marine ecosystems. Despite the economic and ecological importance of the calanoid copepod Temora longicornis in the Belgian part of the North Sea, molecular data is still very limited for this species. Using HiSeq Illumina sequencing, we sequenced the whole transcriptome of T. longicornis, after being exposed to realistic temperatures of 14 and 17 °C. After both an acute (1 day) and a more sustained (5 days) thermal exposure to 17 °C, we investigated gene expression differences with animals exposed to 14 °C, which may be critical for the thermal acclimation and resilience of this copepod species. We also studied the possibility of a short term stress recovery of a heat shock. A total of 179,569 transcripts were yielded, of which 44,985 putative ORF transcripts were identified. These transcripts were subsequently annotated into roughly 22,000 genes based on known sequences using Gene Ontology (GO) and KEGG databases. Temora only showed a mild response to both the temperature and the duration of the exposure. We found that the expression of 27 transcripts varied significantly with an increase in temperature of 3 °C, of which eight transcripts were differentially expressed after acute exposure only. Gene set enrichment analysis revealed that, overall, T. longicornis was more impacted by a sustained thermal exposure, rather than an immediate (acute) exposure, with two times as many enriched GO terms in the sustained treatment. We also identified several general stress responses independent of exposure time, such as modified protein synthesis, energy mobilisation, cuticle and chaperone proteins. Finally, we highlighted candidate genes of a possible recovery from heat exposure, identifying similar terms as those enriched in the heat treatments, i.e. related to for example energy metabolism, cuticle genes and extracellular matrix. The data presented in this study provides the first transcriptome available for T. longicornis which can be used for future genomic studies
<i>In situ</i> biodegradation, photooxidation and dissolution of petroleum compounds in Arctic seawater and sea ice
Full text linkIn pristine sea ice-covered Arctic waters the potential of natural attenuation of oil spills has yet to be uncovered, but increasing shipping and oil exploitation may bring along unprecedented risks of oil spills.We deployed adsorbents coated with thin oil films for up to 2.5 month in ice-covered seawater and sea ice in Godthaab Fjord, SW Greenland, to simulate and investigate in situ biodegradation and photooxidation of dispersed oil.GC-MS-based chemometric methods for oil fingerprinting were used to identify characteristic signatures for dissolution, biodegradation and photooxidation. In sub-zero temperature seawater, fast degradation of n-alkanes was observed with estimated half-life times of ∼7 days. PCR amplicon sequencing and qPCR quantification of bacterial genes showed that a biofilm with a diverse microbial community colonised the oil films, yet a population related to the psychrophilic hydrocarbonoclastic gammaproteobacterium Oleispira antarctica seemed to play a key role in n-alkane degradation. Although Oleispira populations were also present in sea ice, we found that biofilms in sea ice had 25 to 100 times lower bacterial densities than in seawater, which explained the non-detectable n-alkane degradation in sea ice. Fingerprinting revealed that photooxidation, but not biodegradation, transformed polycyclic aromatic compounds through 50 cm-thick sea ice and in the upper water column with removal rates up to ∼1% per day.Overall, our results showed a fast biodegradation of n-alkanes in sea ice-covered seawater, but suggested that oils spills will expose the Arctic ecosystem to bio-recalcitrant PACs over prolonged periods of time