Oceanographic moorings as year-round laboratories for investigating growth performance and settlement dynamics in the Antarctic scallop Adamussium colbecki (E.A. Smith, 1902)

Background: Oceanographic moorings (OMs) are standard marine platforms composed of wires, buoys, weights and instruments, and are used as in situ observatories to record water column properties. However, OMs are also comprised of hard substrates on which a variety of invertebrates can settle when they encounter these structures along their dispersal routes. In this contribution, we studied the fouling communities found on two OMs deployed in the Ross Sea (Antarctica). Furthermore, a cage containing the Antarctic scallop Adamussium colbecki (E. A. Smith, 1902) was incorporated in the OM. The growth of the caged A. colbecki were evaluated after 1 year and their shells used as biological proxy for seawater temperature and salinity. Methods: A variety of settlers were collected from two different OMs deployed in the Ross Sea (Antarctica) and species identified using a combination of morphological and genetic (mainly through DNA barcoding) characteristics. Caged scallops were individually marked with permanent tags and their growth studied in terms of size-increment data (SID). Cages were specifically designed to prevent damage to individuals due to water drag during OM deployment and retrieval. Growth parameters from the caged individuals were applied to the A. colbecki juveniles that had settled on the mooring, to trace the likely settlement period. Results: The growth performance of caged A. colbecki was similar to that from previous growth studies of this species. The remarkable survival rate of caged specimens (96.6%) supports the feasibility of caging experiments, even for a species with a fragile shell such as the Antarctic scallop. Some of the new recruits found on the mooring were A. colbecki, the same species we put into special cages fixed to it. The settlement of the A. colbecki juveniles started during the Austral spring with a peak in summer months and, remarkably, coincided with seasonal changes in water temperature and flow direction, which were recorded by the mooring\u2019s instruments. Genetic data from other settlers provided new information about their larval ecology and connectivity. Discussion: Oceanographic moorings are expensive and complex experimental platforms that, at present, are strictly used for the acquisition of physical and biogeochemical data. Their use for in situ ecological experiments on model organisms suitable for caging and to study fouling species has yet to be fully explored. We present the outcomes of a study, which represents a baseline for the characterization of Antarctic fouling biodiversity. We hope that in the near future an internationally coordinated systematic study of settlers could be initiated around the Antarctic continent. This could utilize \u201cnew generation OMs\u201d equipped with standardized settlement structures and agreed sampling protocols for the study of fouling communities

Neustonic microplastics in the Southern Adriatic Sea. Preliminary results.

Neustonic micro-plastic abundance and polymeric composition were determined after a cruise conducted in the Southern Adriatic Sea between May 9th and 17th 2013. Plankton samples were collected using a Neuston net (200 µm mesh size) which sampled the first 50 cm of the sea surface at a speed of ~2 kts for 5-6 minutes. Samples were then stored in ethanol 70% and in the laboratory micro-plastics were hand-picked using a dissecting stereomicroscope, counted, weighed and split into 7 different size classes. On a subset of collected particles (> 0.7mm) FT-IR analyses were performed to characterize the polymeric composition of the items. All 29 surface tows contained plastic particles of various typologies (e.g. filaments, fragments, thin plastic films), colours and sizes. A total of 5940 plastic particles were collected during the survey, the vast majority of which were hard plastic fragments (78.5%) or synthetic fibers and filaments (19.2%). Most particles were white (27.8%), transparent (22.5%) or black/grey (21.4%). 98.2% of all the particles were < 5 mm and plastic abundance markedly increased with decreasing size (i.e. 52.8% of all the particles were smaller than 0.5 mm), indicating very high fragmentation rates. Overall, an average concentration of 1.05 ± 1.13 particles/m2 and 442.88 ± 1145.96 g/km2 was observed throughout the study area, with micro-plastic densities ranging from 0.10 particles/m2 to a maximum of 4.86 particles/m2. FT-IR analyses indicated polyethylene as the predominant polymer (41%), followed by polyester and paint (12%), polypropylene (10%), polystyrene and polyimide (5%), polyammide (3%), paraffin (4%) and 1% bioplastic (i.e. polycaprolactone). In addition, 7% of the items were characterized as non-plastic materials (i.e. minerals, cellulose and cotton fabric), suggesting a potential bias when visually sorting for micro-plastics. On the whole, very high levels of plastic pollution have been found in our study area. Despite any clear geographical pattern in plastic distribution was identified, the conspicuous spatial heterogeneity in plastic abundances and polymeric compositions seem to confirm the existence of multiple pollution sources insisting on the Adriatic Sea

Downslope processes, deep ventilation and meridional overturning circulation

The processes governing the continental shelf break and deep ocean interactions are crucial to an understanding of the global climate system. In particular, downslope processes, deep ocean ventilation and meridional oceanic overturning circulation control the main exchange between the Southern Ocean and the Atlantic, Indian and Pacific Oceans. However, the Southern Hemisphere is often given too little weight in our analyses and this leads to an underestimation of the role of these processes in global climate evolution at the right time scale

Desde microorganismos a la macrofauna: un estudio comparativo de las comunidades bentónicas profundas y su respuesta a las variables ambientales a lo largo del talud de Malta (mar Jónico)

A comparative study for abundance, biomass and diversity was carried out for the prokaryote, meiofauna and macrofauna communities at three depth stations (1200, 1800 and 2100 m) along the Malta Escarpment (Mediterranean Sea). Our investigation showed a two-fold increase with depth in prokaryote abundance; the contribution of prokaryote biomass to the total benthic biomass was predominant at all depths. Bacteria were the dominant prokaryote component and Archaea formed a considerable fraction (20%-30%) of the prokaryote assemblages. The meio- and macrofauna abundances and meiofauna biomass did not decrease significantly with depth but macrofauna biomass did. The α diversity did not follow a clear bathymetric trend for both nematode and macrofauna species. Probably because of the large number of eurybathic nematode genera, nor did the turnover diversity in nematode composition change down the depth gradient. Conversely, for the macrofauna there was a perceptible change in community composition between the shallowest station and the two deeper stations. Food availability affected only the macrobenthic component. The increase in the prokaryote organisms with depth and the dominance of nematodes and macrofauna deposit feeders suggest active grazing by the two benthic components on microbes. This would transfer energy to the higher trophic levels through the microbial compartment.Se llevó a cabo un estudio comparativo de las comunidades de procariotas, meiofauna y macrofauna sobre la abundancia, biomasa y diversidad. Fue realizado en tres estaciones en varias profundidades (1200, 1800 y 2100 m) a lo largo del talud de Malta (mar Mediterráneo). Nuestra investigación muestra que, aumentando la profundidad, la abundancia de procariotas se duplica. La contribución de la biomasa procariota al total de la biomasa bentónica predominó en todas las profundidades. Las bacterias eran la fracción procariota dominante y junto con los Archaea representaban al 20-30% del total de procariotas. Por otra parte la abundancia de la meiofauna y macrofauna y la biomasa de la meiofauna no disminuían significativamente con la profundidad, mientras que la biomasa de la macrofauna sí lo hacía. La diversidad α no siguió una tendencia batimétrica muy clara para las especies de los nematodos y macrofauna. Probablemente debido a la gran abundancia de géneros de nematodos eurybatiales, la tasa derenovación de la diversidad en la composición de nematodos tampoco cambió por el gradiente de profundidad. En cambio, para la macrofauna hubo un cambio apreciable en la composición de la comunidad entre la estación más superficial y las dos estaciones más profundas. La disponibilidad de alimentos afectó sólo al componente macrobentónico. El aumento con la profundidad de los organismos procariotas, el dominio de los nematodos y la macrofauna que se alimenta de los materiales depositados sugieren un medio activo para los dos componentes bentónicos microbianos. Esto daría lugar a una transferencia de energía a niveles tróficos superiores a través del compartimento microbiano

From microbes to macrofauna: an integrated study of deep benthic communities and their response to environmental variables along the Malta Escarpment (Ionian Sea)

A comparative study for abundance, biomass and diversity was carried out for the prokaryote, meiofauna and macrofauna communities at three depth stations (1200, 1800 and 2100 m) along the Malta Escarpment (Mediterranean Sea). Our investigation showed a two-fold increase with depth in prokaryote abundance; the contribution of prokaryote biomass to the total benthic biomass was predominant at all depths. Bacteria were the dominant prokaryote component and Archaea formed a considerable fraction (20%-30%) of the prokaryote assemblages. The meio- and macrofauna abundances and meiofauna biomass did not decrease significantly with depth but macrofauna biomass did. The α diversity did not follow a clear bathymetric trend for both nematode and macrofauna species. Probably because of the large number of eurybathic nematode genera, nor did the turnover diversity in nematode composition change down the depth gradient. Conversely, for the macrofauna there was a perceptible change in community composition between the shallowest station and the two deeper stations. Food availability affected only the macrobenthic component. The increase in the prokaryote organisms with depth and the dominance of nematodes and macrofauna deposit feeders suggest active grazing by the two benthic components on microbes. This would transfer energy to the higher trophic levels through the microbial compartment

The occurrence of paraffin and other petroleum waxes in the marine environment: A review of the current legislative framework and shipping operational practices

Among the various materials that make up marine debris, lumps of petroleum waxes such as paraffin and microcrystalline wax, are regularly found on beaches worldwide, although not included in the current definition of marine litter. Ingestion by marine organisms is occasionally documented in the scientific literature and mass beaching events are frequently reported along the European coasts, with obvious detrimental consequences to the local communities that have to manage the clean-up and disposal of this substance. According to Annex II of the MARPOL regulation, petroleum waxes are classified as "high viscosity, solidifying, and persistent floating products," whose discharge at sea of tank-washing residues is strictly regulated, but currently permitted within certain limits. Starting from the description of a large stranding event occurred along the Italian coasts in 2017, we review the existing knowledge and regulatory framework and urge the relevant authorities to address this issue, showing that wax pollution is creating evident damages to the European coastal municipalities. Pending further investigations on the potential hazard that this kind of pollution is posing to marine ecosystems, we suggest a careful and more stringent revision of the policies regulating discharges of these products at sea

Late Pleistocene pteropods, heteropods and planktonic foraminifera from the Caribbean Sea, Mediterranean Sea and Indian Ocean

Pteropods and heteropods (holoplanktonic gastropods) are an important component of the modern oceans; however, detailed information on their distribution in the fossil record is often based on poorly preserved specimens. This study presents the micropaleontological analysis of three exceptionally well-preserved Late Pleistocenemarine sediment cores from the eastern Caribbean Sea, westernMediterranean Sea and the Indian Ocean. This study presents the first stratigraphical record of heteropods in the Caribbean Sea and extends the known zonation of pteropods in the Mediterranean Sea. Distributions of pteropods, heteropods and planktonic foraminifera are presented with abundance and species richness data, as well as stratigraphical dates inferred from the oxygen isotope stratigraphy, argon-argon dating and biostratigraphy. The findings of this study greatly improve our understanding of holoplanktonic gastropod stratigraphy and ecology. Results reveal that the geographical range of heteropods, thought to be restricted to sub-tropical warm waters,may be much greater, including waters of sub-polar temperature. Heteropods were also found to be surprisingly abundant, potentially representing a more important part of the ocean food web than previously thought. Analysis revealed two species of holoplanktonic gastropod that are previously undescribed and indicate that the pteropod Heliconoides mermuysi (Cahuzac and Janssen 2010), known exclusively from the Moulin de Cabanes (Miocene),may have lived in theCaribbean Sea and Indian Ocean as recently as 4 kyr ago. These findings highlight the urgent need for increased research on holoplanktonic gastropods. The threat that current climate change and ocean acidification poses, particularly to the delicately shelled forms, means that some species may become extinct before they have even been fully ‘discovered’

Marine Litter Windrows: A Strategic Target to Understand and Manage the Ocean Plastic Pollution

Windrow is a long-established term for the aggregations of seafoam, seaweeds, plankton and natural debris that appear on the ocean surface. Here, we define a "litter windrow" as any aggregation of floating litter at the submesoscale domain (<10 km horizontally), regardless of the force inducing the surface convergence, be it wind or other forces such as tides or density-driven currents. The marine litter windrows observed to date usually form stripes from tens up to thousands of meters long, with litter densities often exceeding 10 small items ( 2 cm) per m2 or 1 large item ( 2 cm) per 10 m2. Litter windrows are generally overlooked in research due to their dispersion, small size and ephemeral nature. However, applied research on windrows offers unique possibilities to advance on the knowledge and management of marine litter pollution. Litter windrows are hot spots of interaction with marine life. In addition, since the formation of dense litter windrows requires especially high loads of floating litter in the environment, their detection from space-borne sensors, aerial surveys or other platforms might be used to flag areas and periods of severe pollution. Monitoring and assessing of management plans, identification of pollution sources, or impact prevention are identified as some of the most promising fields of application for the marine litter windrows. In the present Perspective, we develop a conceptual framework and point out the main obstacles, opportunities and methodological approaches to address the study of litter windrows.This study is an outcome of the research project entitled "MappingWindrows as Proxy for Marine Litter Monitoring from Space" (WASP), funded by the European Space Agency (ESA) Contract No. 4000130627/20/NL/GLC, within the Discovery Campaign in Marine Litter. AC had additional support from MIDaS (CTM2016-77106-R, AEI/FEDER/UE), and SA from PRIN 2017-2017WERYZP-EMME project. AI was supported by the Environmental Research and Technology Development Fund (JPMEERF18S20201) of the Ministry of the Environment, Japan, and by SATREPS of Japan International Cooperation Agency and Japan Science and Technology Agency. OB and AR contribution was funded through the EU's LIFE Program (LIFE LEMA project, grant agreement no. LIFE15 ENV/ES/000252). This is contribution number 1016 of AZTI, Marine Research, Basque Research and Technology Alliance (BRTA)

Multidisciplinary Investigation at Panarea (Aeolian Islands) After the Exhalative Crisis of 2002.

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The Mediterranean Plastic Soup: synthetic polymers in Mediterranean surface waters

The Mediterranean Sea has been recently proposed as one of the most impacted regions of the world with regards to microplastics, however the polymeric composition of these floating particles is still largely unknown. Here we present the results of a large-scale survey of neustonic micro- and meso-plastics floating in Mediterranean waters, providing the first extensive characterization of their chemical identity as well as detailed information on their abundance and geographical distribution. All particles >700 μm collected in our samples were identified through FT-IR analysis (n = 4050 particles), shedding for the first time light on the polymeric diversity of this emerging pollutant. Sixteen different classes of synthetic materials were identified. Low-density polymers such as polyethylene and polypropylene were the most abundant compounds, followed by polyamides, plastic-based paints, polyvinyl chloride, polystyrene and polyvinyl alcohol. Less frequent polymers included polyethylene terephthalate, polyisoprene, poly(vinyl stearate), ethylene-vinyl acetate, polyepoxide, paraffin wax and polycaprolactone, a biodegradable polyester reported for the first time floating in off-shore waters. Geographical differences in sample composition were also observed, demonstrating sub-basin scale heterogeneity in plastics distribution and likely reflecting a complex interplay between pollution sources, sinks and residence times of different polymers at sea