Validation of Arenicola marina in field toxicity bioassays using benthic cages: biomarkers as tools for assessing sediment quality

Sediment toxicity assessments using caged organisms present advantages over using laboratory and native community studies. The use of caged Arenicola marina in sediment toxicity assessments was evaluated. Lugworms were exposed in situ to sediments from coastal and port areas in Spain for seven days, and the activities of the biotransformation enzymes ethoxyresorufin O-deethylase, dibenzylfluorescein dealkylase and glutathione S-transferase, the activities of the antioxidant enzymes glutathione reductase and glutathione peroxidase and lipid peroxidation were then analyzed as biomarkers. Biomarker results and sediment physicochemical data were integrated. Cádiz Bay (SW Spain) sediments presented metal contamination that was not linked to a biochemical response. In LPGC Port (SW Spain), Pb contamination exhibited a moderate toxic potential, while PAHs, and presumably pharmaceuticals, provoked biochemical responses that efficiently prevented lipid peroxidation. In Santander Bay (N Spain), exposure to PAHs and, presumably, pharmaceuticals induced biomarker responses, but lipid peroxidation occurred nevertheless. These results indicated that caged A. marina were effective for the assessment of sediment quality and that the selected biomarkers were sufficiently sensitive to identify chemical exposure and toxicity.     

Plastic marine debris on the Portuguese coastline: a matter of size?

Plastic debris is a worldwide threat to marine environments and Portugal is not immune to it. Though never quantified, items of all sizes can be found in the Portuguese coastline; therefore the objective of this work is the identification of main size classes in stranded plastic debris. Beaches sediment was sampled and in the laboratory plastic items were sorted in 11 classes from <1 to >10 mm, counted and weighted. Plastic size ranged from 50 μm to 20 cm and microplastics (<5 mm) were the majority (72%). Most plastic fits in the smaller size classes, due to expected high residence time in the sea enhancing degradation processes, which increase surface exposure and potentially persistent organic pollutants (POP) adsorption. These results point out the important contribution of microplastics to marine debris pollution, its risks, and the need to set a higher focus on this size class.     

Report on the 4th International Meeting of the IUGS Lower Cretaceous Ammonite Working Group, the “Kilian Group” (Dijon, France, 30th August 2010)

The 4th Kilian Group meeting (Dijon, France, 30th August 2010) focused on the Aptian and Albian Stages. For the Aptian, a two-fold division of the stage was adopted for the Mediterranean area with a boundary between the Dufrenoyia furcata and Epicheloniceras martini Zones. The main changes to the zonal scheme concern the Lower Aptian with: the introduction of a Deshayesites luppovi Subzone in the upper part of the Deshayesites oglanlensis Zone; the replacement of Deshayesites weissi by Deshayesites forbesi as new index-species of the second interval zone; the introduction of a Roloboceras hambrovi Subzone in the upper part of the D. forbesi Zone; and the subdivision of the D. furcata Zone into the D. furcata and Dufrenoyia dufrenoyi Subzones. For the Albian, the upper part of the Douvilleiceras mammillatum Zone (Lower Albian) is now characterized by a Lyelliceras pseudolyelli Subzone. The main amendments concern the Upper Albian. The base of this substage is defined by the base of the Dipoloceras cristatum Zone. Above it, the Upper Albian zonal scheme comprises in stratigraphic order the Mortoniceras pricei, Mortoniceras inflatum, Mortoniceras fallax, Mortoniceras rostratum, Mortoniceras perinflatum and Arrhaphoceras briacensis Zones.     

Late Albian (Early Cretaceous) ammonites from the Provincial Formation of central Cuba

A late Albian ammonite assemblage from the Provincial Formation of Villa Clara Province, Cuba is described. The Provincial Formation is a lithostratigraphic unit of Albian-Cenomanian age extensively exposed in central Cuba and formed within a part of the Caribbean Tethys that was volcanic during the Cretaceous. The formation is mainly composed of calcareous, terrigenous marine, and volcano-sedimentary deposits characterized by a series of micritic limestones intercalated with marls, sandstones, calcareous conglomerates, ash, and tuffaceous material. A rich assemblage of ammonites recovered from the calcareous biomicrites and marls is of late Albian (Stoliczkaia dispar Zone, Mortoniceras rostratum Subzone) age. The ammonite fauna shows a strong Tethyan affinity, and only a single hoplitid ammonite species was recorded. Although scarce, the first Cuban report of this and other boreal ammonite species now allows precise correlations to be made between Cuba and Albian sediments elsewhere in the world.     

Magnetostratigraphy and paleomagnetism of early and middle Miocene synorogenic strata: basement partitioning and minor block rotation in Argentine broken foreland

Magnetostratigraphic and paleomagnetic studies on early Andean synorogenic strata (Del Crestón Fm.), in the Famatina Belt (28.7°S, 67.5°W) clarify details of chronology that permit calculation of sedimentation rates within the broken foreland of west Argentina. The Del Crestón Fm represents the first record of broken foreland sedimentation within the southern Central Andean belt and the earliest retroarc volcanic rocks exposed several hundred kilometers from the trench. Twenty-five out of 49 sites collected along the succession presented a primary remanence, as determined through positive fold and reversal tests. Correlation of the local magnetic polarity section with the global polarity time scale indicates that the sedimentation of Del Crestón Fm started at ~16.7 Ma and continued until ~14.5 Ma. The youngest strata are represented by conglomerates bearing abundant Lower Paleozoic granite boulders indicating unroofing of the crystalline basement within the NW Sierras Pampeanas. This result supports the hypothesis of an early broken foreland stage at these latitudes of the Andes, with involvement of the basement in deformation and coeval retroarc volcanism, common attributes of flat-subduction regimes. A mean site paleomagnetic direction of Dec: 6.3°, Inc: ?43.6° (α95: 8.0°, N = 24) confirm our earlier intrepretation that the central part of the Famatina Belt within the Sierras Pampeanas did not undergo large vertical axes rotations since the Middle Miocene.     

Mercury, copper and zinc contamination in soils and fluvial sediments from an abandoned gold mining area in southern Minas Gerais State, Brazil

Mercury, zinc and copper contamination was evaluated in soils and fluvial sediments from an abandoned gold mining site at Descoberto Municipality (southern Minas Gerais State, Brazil). Metals bioavailability and potential mobility were studied through physical, chemical and mineralogical characterization, geoaccumulation indexes calculations, mercury speciation and determination of potentially bioavailable contents of zinc and copper. Values of pH were in the neutral range, while organic matter concentrations were very low. Mineralogical characterization, in the total samples, indicated the presence of quartz, kaolinite and gibbsite for all samples. Total mercury, zinc and cooper concentrations were higher than the limits recommended by Brazilian documents. Geoaccumulations indexes revealed that most of the sediment samples were low to moderately polluted by zinc and copper, while just one sample was very strongly polluted by mercury. Mercury speciation revealed the predominance of the elementary form for all samples, and low concentrations for exchangeable, strongly bound and residual fractions. Zinc and copper behavior was strongly controlled by iron and aluminum concentrations, while their bioavailable contents were very low in comparison with the total concentrations.     

Imaging the recent sediment dynamics of the Galicia Bank region (Atlantic,NW Iberian Peninsula)

Multibeam bathymetry, high resolution multi-channel, and very high resolution single-channel (3.5 kHz) seismic records were used to depict the complex geomorphology that defines the Galicia Bank region (Atlantic, NW Iberian Peninsula). This region (≈620–5,000 m water depth) is characterized by a great variety of features: structural features (scarps, highs, valleys, fold bulges), fluid dynamics-related features (structural undulations and collapse craters), mass-movement features (gullies, channels, mass-flow deposits, slope-lobe complexes, and mass-transport deposits), bottom-current features (moats, furrows, abraded surface, sediment waves, and drifts), (hemi)pelagic features, mixed features (abraded surfaces associated to mixed sediments) and bioconstructions. These features represent architectural elements of four sedimentary systems: slope apron, contouritic, current-controlled (hemi)pelagic, and (hemi)pelagic. These systems are a reflection of different sedimentary processes: downslope (mass transport, mass flows, turbidity flows), alongslope (bottom currents of Mediterranean Outflow Water, Labrador Sea Water, North Atlantic Deep Water, and Lower Deep Water), vertical settling, and the interplay between them. The architectural and sediment dynamic complexities, for their part, are conditioned by the morphostructural complexity of the region, whose structures (exposed scarps and highs) favor multiple submarine sediment sources, affect the type and evolution of the mass-movement processes, and interact with different water masses. This region and similar sedimentary environments far from the continental sediment sources, as seamounts, are ideal zones for carrying out submarine source-to-sink studies, and can represent areas subject to hazards, both geologic and oceanographic in origin.     

In situ experimental decomposition studies in estuaries: A comparison of Phragmites australis and Fucus vesiculosus

The decomposition rates of Phragmites australis and Fucus vesiculosus were experimentally determined in an estuarine system using the leaf-bag technique. The study was conducted in fifteen sites arranged in five areas, extending from freshwater, outside the tidal range, to the marine environment, near the mouth of the estuary. The leaf-bags (5 mm mesh), were set up with 3.0 g of dried substrate, submerged in the experimental sites at day 0 and collected at days 3, 7, 15, 30 and 60, to follow biomass loss. The biomass loss through the leaching phase (day 3) was about 16% for Phragmites australis and 33% for Fucus vesiculosus and was independent of salinity for both substrates. The difference in the remaining biomass between the two species increased with time and the decomposition rates differed along the salinity gradient. For F. vesiculosus, the decomposition rate was highest near the mouth of the estuary, corresponding to the preferential distribution area of the algae, and decreased towards freshwater. For Phragmites australis, the fastest decay was observed in the mid estuary, where Phragmites australis occurs naturally, confirming previous studies. The decomposition rates measured at different time intervals (0–15, 0–30 and 0–60 days) were always higher for the algae and decreased with time for both species. These results indicate that the use of decomposition rates as a measure of ecosystem integrity or quality status in transitional waters will not be straightforward and must take into account, among others, the test species, the study area positioning along the estuarine gradient, and the time interval for the calculation of the decomposition rate.     

Relationship between metal levels in the vent mussel Bathymodiolus azoricus and local microhabitat chemical characteristics of Eiffel Tower (Lucky Strike)

The turbulent mixing of hydrothermal hot fluid with cold seawater creates large chemical gradients at a small spatial scale that may induce variable physiological and biochemical adaptations within the vent fauna. The adaptation to such a variable environment by the vent mussel Bathymodiolus azoricus relies on a dual symbiosis hosted in the gills, and digestion of particulate organic matter. The surrounding environment not only provides the necessary energy sources and suspended organic particles for the vent mussel nutrition, but also potentially toxic compounds such as metals. Our main goal was to see if there is a relation between metal accumulation in mussel organs and the chemical characteristics of their close environment. Mussels were collected at six locations in a cold part of the Eiffel Tower fluid-seawater mixing zone, characterized by distinct chemical compositions. Metals (Cd, Cu, Fe and Zn) and metallothioneins were quantified in the gills and digestive gland. The physiological condition of the sampled mussels was also evaluated using tissues and gill indices. Our study indicates that the accumulation of metals in B. azoricus is related to their spatial distribution and linked to fine scale environmental conditions that influence the physiological status of the organism.