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The transfer of nutrients and energy from carcasses to scavengers is an important ecosystem function. In marine ecosystems, mammal carcasses can represent a spatiotemporally restricted but substantial pulse in resource availability, as they are typically only briefly available to scavengers on the surface. Little is understood about how these scavengers respond to such pulses, or how inter-scavenger interactions may influence their behaviour. We describe scavenging interactions of procellariiform seabirds at a fresh and floating New Zealand Fur Seal Arctocephalus forsteri carcass, recently killed by a White Shark Carcharodon carcharias, over the continental slope of southeastern Australia. We highlight potential exclusive and facilitative interactions between the shark and various seabirds, which may play an important role in energy-transfer dynamics in surface pelagic environments. We also provide apparently novel descriptions of scavenging at a marine mammal carcass for six of the seven seabird species that attended the carcass. Further study of sea-surface scavenger behaviour, interactions, and ecology will provide valuable insights into energy-transfer dynamics in pelagic ecosystems. [ABSTRACT FROM AUTHOR]

Fluctuations in prey abundance, composition, and distribution can impact predators, and when predators and fisheries target the same species, predators become essential to ecosystem‐based management. Because of the difficulty in collecting concomitant predator–prey data at appropriate scales in patchy environments, few studies have identified strong linkages between cetaceans and prey, especially across large geographic areas. During summer 2018, a line‐transect survey for cetaceans and coastal pelagic species was conducted over the continental shelf and slope of British Columbia, Canada, and the US West Coast, allowing for a large‐scale investigation of predator–prey spatial relationships. We report on a case study of humpback whales (Megaptera novaeangliae) and their primary prey—Pacific herring (Clupea pallasii), northern anchovy (Engraulis mordax), and krill—using generalized additive models to explore the relationships between whale abundance on 10‐km transect segments and prey metrics. Prey metrics included direct measures of biomass densities on segments and an original hotspot metric. For each prey species, segments in the upper fifth percentile for biomass density (across all segments) were designated hotspots, and whale counts on a segment were evaluated for their relationship to number of hotspot segments (species‐specific and multispecies) within 25, 50, or 100 km. Whale abundance was not strongly related to direct measures of biomass densities, whereas models using hotspot metrics were more effective at describing variation in whale abundance, underscoring that evaluating prey at relevant and measurable scales is critical in patchy, dynamic marine environments. Our analysis highlighted differences in the distribution and prey availability for three humpback whale distinct population segments (DPSs) as defined under the US Endangered Species Act, including threatened and endangered DPSs that forage within the California Current Large Marine Ecosystem. These linkages provide insights into which prey species whales may be targeting in different regions and across multiple scales and, consequently, how climatic variability and anthropogenic risks may differentially impact these distinct predator–prey assemblages. By identifying scale‐appropriate prey hotspots that co‐occur with humpback whale aggregations, and with targeted, consistent prey sampling and estimations of potential consumption rates by whales, these findings can help inform the conservation and management of humpback whales within an ecosystem‐based management framework. [ABSTRACT FROM AUTHOR]

This article presents the findings of a research project conducted in the Santos Basin, Brazil, which aimed to collect comprehensive oceanographic data for future environmental management in offshore oil and gas regions. The study examined various aspects of the benthic and pelagic environments, including physical, chemical, sedimentological, and biological factors. The research findings are categorized into methodological aspects, hydrographic conditions, pelagic ecosystems, and benthic ecosystems. The ultimate goal of the project is to balance sustainable oil and gas exploration with the preservation of regional biodiversity and environmental health. The article also discusses the study of meiofauna and the use of machine learning techniques to identify distinct benthic zones with unique environmental conditions. Additionally, the study highlights differences in macrofauna and foraminifera between the northern and southern sectors of the slope. The implementation of ecosystem-based management (EBM) in the Santos Basin faces challenges such as distinguishing natural variability from human-mediated changes and involving relevant stakeholders. However, it is crucial to base EBM on high-quality scientific data to ensure the long-term preservation of marine ecosystems. [Extracted from the article]

This work describes the circulation over the continental slope and the São Paulo Plateau in the Santos Basin during the SANSED winter 2019 survey. The cruise consisted of four legs in the period between June, 11 and August, 03 2019. The observed circulation is dominated by the Atlantic southwestern boundary current regime and remotely-generated anticyclones and cyclones. The former is composed by the Brazil Current, the Intermediate Western Boundary Current and their mesoscale meanders; the latter are 300km vortical rings with origin in the eastern side of the South Atlantic Basin. A Lagrangian scheme applied over satellite altimeter maps indicate that the origin of these rings is primarily the Cape Basin off South Africa. The interaction between the boundary currents, their cyclonic meanders, and the anticyclonic rings is complex, and varies widely. During the SANSED winter 2019 survey period, three anticyclones interacted with the Brazil Current, instabilizing it, forming dipoles with the current cyclonic meanders, leading to their downstream propagation. Ancienter cyclonic eddies within Santos Basin may interfere with the propagation of the large anticyclones further south. In addition, the continuous arrival of remotely-originated anticyclones, the larger portion over the São Paulo Plateau presented a tendency of counter-clockwise circulation during the whole cruise period. [ABSTRACT FROM AUTHOR]

Continental margins usually have a high degree of environmental heterogeneity, which, in turn, promotes high benthic biodiversity. The South-Southeast regions concentrate the most well-mapped areas of the Brazilian continental margin regarding seafloor geomorphology and physical oceanography. However, the structure of the soft-sediment benthic fauna of the continental slope is still unknown. Characterization and understanding of the Brazilian continental slope biota are imperative since human activities are increasing in the last decades, especially after the discovery of the pre-salt reservoir in Santos Basin. In this study, we aimed to establish a baseline of the spatial distribution of the benthic macrofaunal communities regarding their latitudinal and bathymetric patterns in the Santos Basin to support future environmental monitoring activities in the region. As part of the Santos Project - The Santos Basin Regional Environmental Characterization (PCR-BS) - coordinated by CENPES/PETROBRAS, a benthic oceanographic cruise was carried out in 2019. Sediment samples were collected using a GOMEX-type box corer in 47 stations distributed in eight transects (4002,400 m depth range). In total, 12 additional stations (1,300-2,200 m) were defined to cover an area where oil and gas are exploited. Our results showed that macrofaunal assemblages of the Santos Basin present strong depth zonation related to changes in organic matter input, as well as to temperature, carbonate, and grain size. At local scale, the northern sector stood out for having a higher abundance of macrofauna in the upper slope (400 m) and it probably reflects the oceanographic processes and the organic enrichment caused by the upwelling events that occur at Cabo Frio region. The zonation pattern and the dominance of some polychaete, peracarid crustacean, and bivalve families were similar to other SE Brazilian continental margins. [ABSTRACT FROM AUTHOR]

The extensive coverage of 3-D seismic data on the Santos Basin deep water offered an integrated vision of the local physiography and medium- to small-scale geomorphological features, which enhances the understanding of its constructive/deconstructive natural processes and their interrelations. The Santos Basin is a divergent marginal basin composed of three main physiographic provinces: its continental shelf, continental slope, and the São Paulo Plateau, whose dimensions, orientation, gradients, and relief interact with oceanographic, biological, and geological processes. This study geologically contextualized environmental data related to the Regional Environmental Characterization Project of the Santos Basin (hereinafter referred to as PCR-BS), especially regarding the regional physiographical architecture and deep-water geomorphological provinces as a background for the benthic communities and the distribution of several of its geochemical parameters. The integrated analysis of 3-D seismic and multibeam bathymetric data and its derivatives (gradient and edge maps) -- calibrated by 108 piston cores -- aimed to evaluate its seafloor physiographic features and geological processes. Edge detection seismic attributes enhance gradient contrast, which, in turn, can map innumerous medium- to small- scale geomorphic features (features solved in maps at a 1:1,000,000 scale or larger), such as canyons, channels, ravines, pockmark units, pockmark fields, lineaments, carbonate and coral mounds, salt-related features (crests, minibasins, and crestal grabens), scars and rugous relief associated with mass-transport deposits, and bottom current-related features (depressions and furrows). The slope and the gently dipping plateau (São Paulo Plateau) that follow it eastward show four geomorphological domains based on their direction, profile, average gradient, shelf break isobath, distribution of its medium-small scale geomorphic features, and the presence or absence of evaporites at subsurface. The central-northern São Paulo Plateau contains salt-related topographic elevations (salt diapirs and walls) and depressions (minibasins) that give a rough aspect to the seafloor relief. [ABSTRACT FROM AUTHOR]

This study aimed to characterize the spatial distribution and composition of living Benthic Foraminifera (BF) and to comprehend how environmental conditions (e.g., organic matter) can affect communities of these protozoa in the northern and southern sectors of the Santos Basin (SB), in the continental slope and São Paulo Plateau. In this context, 23 stations (65 samples including replicates at each station) were collected between 400 and 2,400 m water depth. Multivariate analyses revealed that the ecological structure of the community changes mainly along the bathymetric gradients. Stations located between 400 and 700 m, both in northern and southern sectors, are characterized by the presence of indicator species of high intensity of currents, such as Globocassidulina subglobosa and Trifarina bradyi. These stations are also mainly marked by the occurrence of Epistominella exigua, a phytodetritivore species. The stations at 1,000 and 1,300 m depth, in both sectors, are characterized by high accumulation of organic matter in the sediments, which favors the development of agglutinated foraminifera species, such as those of the genus Reophax. Finally, the lower slope and the São Paulo Plateau, in both sectors, are oligotrophic regions, with pulses of labile organic carbon, probably low current velocities and the presence of Alabaminella weddellensis. The quantity and quality of food, which are closely related to hydro-sedimentary dynamics and bentho-pelagic coupling in the slope and São Paulo Plateau, are the main factors that influence the distribution of living BF assemblages in the SB. [ABSTRACT FROM AUTHOR]

We provide information on the seabirds occurring year-round in waters of the French Guiana Exclusive Economic Zone, based on data obtained from three boat-based campaigns: a campaign by the Groupe d'Étude et de Protection des Oiseaux de Guyane was conducted for four days every two months from July 2011 to June 2012; a campaign by Cohabys was performed for five days per month from January to May 2018; and a campaign by Ocean Science & Logistic consisted of four 10-day surveys conducted in June, July, September, and October 2018. Overall, 30 seabird species within 1 110 groups of birds were sighted along 6 686 km of surveys conducted during favorable weather conditions (Beaufort < 5). Seabirds of the family Laridae were the most frequently observed, followed by those of the family Procellariidae. In waters over the continental slope, the most frequently observed species were Sooty Tern Onychoprion fuscatus; Brown Noddy Anous stolidus; Wilson's Oceanites oceanicus and Leach's Hydrobates leucorhous Storm Petrels; Great Ardenna gravis, Manx Puffinus puffinus, and Audubon's Puffinus lherminieri Shearwaters; and Masked Booby Sula dactylatra. In waters over the shelf, the most common species were Common Tern Sterna hirundo, Laughing Gull Leucophaeus atricilla, and Royal Tern Thalasseus maximus. In the coastal area, the most common species were Laughing Gull, Royal Tern, and Cayenne Tern T. acuflavidus eurygnathus. The Magnificent Frigatebird Fregata magnificens was sighted in all habitats. Monthly presence/absence and associations of species were also analyzed. Our results underline the high species diversity of seabirds within the waters of French Guiana as well as the diverse uses of available habitats. Indeed, the region is not only a major nesting area, but also a major foraging area for wintering, summering, and migrating species. We recommend strengthening seabird conservation measures and, in particular, increasing the extent of Marine Protected Areas. [ABSTRACT FROM AUTHOR]

We report on the occurrence of albatrosses (Diomedeidae) and petrels (Procellariidae) associated with an artisanal small-scale fishery (SSF) for Humboldt Squid Dosidicus gigas in waters of southern Peru during El Niño 2015-2016 and coastal El Niño 2017. We deployed as observers on a number of fishing trips to assess seabird interactions. White-chinned Petrels Procellaria aequinoctialis and Waved Albatross Phoebastria irroata were the most abundant species observed, followed by Salvin's Thalassarche salvini and Chatham T. eremita albatross, and Cape Petrels Daption capense. The majority of procellariid species (> 60% of total birds) visited while vessels were positioned over the continental slope. Salvin's and Chatham albatross, and White-chinned Petrels, were mostly absent during summer (only 5% and 15% of birds present, respectively), but Waved Albatross and Cape Petrels were present year-round. Thus, the prevalence of each of these species was disproportionate relative to expectation based on non-fishery surveys. All assessed species foraged on offal discards associated with the fishery (~17%), with a higher frequency of consumption among Salvin's (27%) and Chatham (21%) albatross; in contrast, Waved Albatross largely fed on pelagic fish at the surface. Bycatch rate was found to be low; one Chatham Albatross was hooked and released in a hand-held squid jig (0.042 By Catch Per Unit Effort [BPUE] per fishing trip, n = 16). Probably due to El Niño conditions, Waved Albatross were more abundant than expected (43.9% of albatross, and 2.8% of total seabirds observed) and were 1 300-1 400 km farther south than their usual southern limits. We report the first sighting of Southern Royal Albatross Diomedea epomophora in Peru. Bycatch in longline fisheries are a conservation concern, but the magnitude and constant growth of SSFs, especially for Humboldt Squid, needs to be further investigated. [ABSTRACT FROM AUTHOR]

The main factors controlling the bulk sedimentation in the region of the Mendeleev Rise and the adjacent part of the Arctic Ocean during the late Cenozoic were studied using a complex of geomorphological, lithological, and organic geochemical data. Samples for the study were collected during the cruises of the R/V Akademik Fedorov in 2000, 2005, and 2007 and icebreaker Kapitan Dranitsyn in 2012. Analysis of the group and molecular compositions of the dispersed organic matter (DOM) in bottom sediments has shown that the input of terrigenous sediments enriched with abrasion products of lithified rocks from the eastern source province determines the Holocene- Pleistocene sedimentation on the continental slope of the East Siberian Sea and in the Podvodnikov Basin. The individual characteristics of DOM of the late Cenozoic deposits from the underwater mountains of the Mendeleev Rise reflect the wide diversity of sedimentary sources and depositional conditions. Subaqueous erosion and redeposition of denudation products of source rocks and pre-Holocene sediments play an important part in sedimentation together with a terrigenous flow and ice transport. [ABSTRACT FROM AUTHOR]

The article presents a detailed analysis of the underwater morphology of the entire Black Sea basin beyond the shelf break. The focus is on submarine valley systems on continental slope and rise zones, and partially in the abyssal plain area. The present research is among the very few studies that have undertaken a morphological analysis on a regional scale, for an entire marine basin. This achievement was possible by using the publicly available EMODnet bathymetric map of the Black Sea. The Black Sea submarine valleys networks are presented in a map-sketch. It includes 25 valley systems, 5 groups of simple first order channels, and other number of simple, not associated channels. The 25 valley systems are adding up more than 110 main channels and tributaries. Morphological description and analysis of each of the mapped systems is given – shape and plan view morphology, dimensions (length and surface) and slope gradient. Some considerations about the amount of sediments supplied by the valleys from the shelf to the basin floor, forming the deep-sea fans, are presented. For a more detailed and precise image of the Black Sea network of submarine valleys additional work would be necessary to cover the entire basin with a minimum standard network of modern bathymetric mapping and of high resolution seismic survey lines. To take into account the composition and geological structure of different sectors, as factors that influence significantly the morphology of the seabed, would be also particularly useful. [ABSTRACT FROM AUTHOR]

The presence of marine litter in the deep ocean (>200 m depth) may represent an invisible threat that has been neglected due to the scarcity of data. Herein, we provide the first report of persistent marine litter on the Southwestern Atlantic continental slope. Marine litter was collected onboard the Brazilian R/V Alpha Crucis , using bottom trawling, in 28 out of 31 sampled stations, between 274 and 1520 m depth, in two distinct areas off the southern Brazilian coast. In total, 603 items and 13.8 kg of litter were collected and classified according to the type of material. Plastic was the most frequent and most abundant material found. Although there was no bathymetric variation along the slope, density of litter was considerably higher off São Paulo than off Santa Catarina State, supposedly due to the heavier presence of oil and gas platforms and large cargo vessels. • The deep ocean is, silently, becoming a dumpster of human trash. • Litter was recovered from the Brazilian continental slope, up to 1520 m depth. • Plastic as a major problem: the most frequent, most abundant, and found in all locations. • Food packages produced over 26 years ago were found deposited on the deep-sea floor. • Highly toxic materials from the marine industry bring extra concern about marine pollution. [ABSTRACT FROM AUTHOR]

Mesoscale eddies have been reported to have a substantial impact on the distribution of phytoplankton through the regulation of environmental variables in the open ocean. However, the influence of warm eddies on phytoplankton in continental slopes remains largely unknown. To reveal the impact of mesoscale eddies within slope regions, we conducted a field investigation of picophytoplankton on the northern slope of the South China Sea during an anticyclonic warm eddy propagation. We observed different picophytoplankton distribution patterns. Synechococcus dominated the picophytoplankton community in the Kuroshio-affected eddy core rather than the previously reported Prochlorococcus , and Prochlorococcus dominated outside the eddy in the shelf. In addition, through further vertical study of typical layers, we found that the influence of warm eddy varied in different layers. Analysis of the mechanisms indicated that the distributions were attributed to warm eddy-induced nutrients and light variations and the physical processes in it. [Display omitted] • Analysis of warm eddy impacts on picophytoplankton in South China Sea slope area • Different distribution pattern of picophytoplankton was observed. • The warm eddy changed the distribution of nutrients and light intensity. • The warm eddy affected the composition of water masses. • The distribution of picophytoplankton was influenced by physical-chemical variations. [ABSTRACT FROM AUTHOR]

Woolpert, a geospatial and design firm, has been recognized for its innovative lidar technology. The firm received the Lidar Leader Outstanding Innovation in Lidar Award for its Bathymetric Unmanned Littoral LiDar for Operational GEOINT (BULLDOG) system, which collects high-resolution topographic and bathymetric data at higher altitudes than previous lidar systems. Woolpert also received the MAPPS Membership Choice Award for its work in delivering mission-critical data for geohazard defense in Alaska. Additionally, the firm's Vice President and Survey Discipline Leader, David Kuxhausen, received the ASPRS Outstanding Service Award. The National Ocean Mapping, Exploration, and Characterization Council and the Interagency Working Group on Ocean and Coastal Mapping are seeking public comment on their draft Standard Ocean Mapping Protocol. [Extracted from the article]

This study explores the first record of spatiotemporal distributions of macro and micro-litter on the seafloor in the Southeastern (SE) Levantine Basin (LB) during 2012–2021. Macro-litter was surveyed by bottom trawls in water depths of 20-1600 m and micro-litter by sediment box corer/grab at a depths range of 4-1950 m. Maximal macro-litter concentrations were recorded at the upper continental slope (200 m), averaging 4700 ± 3000 items/km2. Plastic bags and packages were the most abundant items (77 ± 9 %) with a maximum of 89 % at 200 m depth, and their size decreased with increasing water depth. Micro-litter debris were found mainly in shelf sediments (≤30 m water depth) with an average concentration of 40 ± 50 items/kg, while shit particles transferred to the deep sea. These findings suggest an extensive distribution of plastic bags and packages in the SE LB, predominantly accumulating in the upper continental slope and deeper, based on their size. • Spatiotemporal distributions of macro & micro-litter were studied for the 1st time in the SE Levantine Basin. • Maximal macro-litter concentrations were recorded at the upper continental slope. • Plastic bags and packages were the most abundant items, and their size decreased with increasing water depth. [ABSTRACT FROM AUTHOR]

Geochemical analyses were used to determine the origin and identify the main factors that lead to the metal trace distribution on the surface sediments from the continental slope of Sergipe in Brazil. Sediment samples were collected during the dry and rainy periods, from 36 sampling points distributed at water depths from 400 to 3000 m. In general, no effect of seasonality was observed on the metal concentrations and no significant differences were observed between the depth ranges. The correlation analysis indicated the continental origin as the most predominant, followed by authigenic deposition. Anthropogenic enrichment was not noted, nor was the possibility of adverse aquatic biota effects. The results made it possible to understand the contribution of rivers in the transport and transfer of particulate matter to the coastal region, in addition to providing new information on the content of trace metals in tropical Atlantic sediments. [Display omitted] • The distribution of trace metals did not exhibit any significant difference with depth. • No seasonality effect was noted. • Metal geochemistry was studied in the sediment from the continental slope. • Enrichment factor indicated the non-occurrence of anthropogenic enrichment. • The sediment quality assessed rarely present adverse effects on aquatic biota. [ABSTRACT FROM AUTHOR]

Despite being generally located far from contamination sources, deep marine ecosystems are impacted by chemicals like PCB. The PCB contamination in five fish and shark species collected in the continental slope of the Gulf of Lions (NW Mediterranean Sea) was measured, with a special focus on intra- and interspecific variability and on the driving factors. Significant differences occurred between species. Higher values were measured in Scyliorhinus canicula , Galeus melastomus and Helicolenus dactylopterus and lower values in Phycis blennoides and Lepidorhombus boscii . These differences might be explained by specific abilities to accumulate and eliminate contaminant, mostly through cytochrome P450 pathway. Interindividual variation was also high and no correlation was observed between contamination and length, age or trophic level. Despite its major importance, actual bioaccumulation of PCB in deep fish is not as documented as in other marine ecosystems, calling for a better assessment of the factors driving individual bioaccumulation mechanisms and originating high variability in PCB contamination. [ABSTRACT FROM AUTHOR]

Marine microplastic pollution has become a major global concern in recent years and the fate of microplastics in the ocean is a hot issue of research. We investigated microplastic pollution in surface sediments in the northern South China Sea to explore its distribution characteristics and influencing factors across the continental shelf, continental slope, and deep-sea environments. It was found that the microplastic abundance of surface sediments was 130.56 ± 40.48 items/kg. The average abundance of microplastics in all three topographic areas gradually decreased with increasing distance offshore. However, the differences in microplastic diversity indices between the three areas were not significant and were higher than those in other seas of the world, indicating that the waters of the northern South China Sea are rich in microplastics from complex sources, with more pollution input channels. In the continental shelf, fibrous and low density microplastics accounted for the largest amount, with a low degree of microplastic aging, and were mostly transported by suspended-load. These microplastics were mainly influenced by human activities. In the deep sea, microplastics with higher density were the most abundant and the number of fibrous microplastics was fewer, while the average size was larger, mainly influenced by the bottom currents. These microplastics underwent long-term bedload transport. In the continental slope, the main factors affecting the distribution of microplastics were more complex. In addition to pollution by human activities, the slope also receives microplastic materials carried by bottom currents; therefore, the composition of microplastics in the slope combines those characteristics of microplastics in both the continental shelf and deep-sea areas. The findings of this study indicate that the South China Sea is affected by complex pollution sources under the dual effects of human activities and natural conditions; in particular, the pollution situation in the deep-sea area needs extensive attention. [Display omitted] • Distribution of microplastic and characteristics from the northern SCS are reported. • MPs distribution is mainly affected by human activities and bottom currents. • Continental shelf has higher abundance than continental slope and deep-sea areas. • Deep-sea areas potentially pool large amounts of microplastics. • Prominent MDI in northern SCS reflects the diversity of pollution input channels. [ABSTRACT FROM AUTHOR]

Seafloor pollution by benthic litter is an emerging phenomenon, although debris colonization by biota remains largely unexplored. We characterized the litter of the continental slope (~400–600 m) of the Gulf of Naples (Mediterranean) and investigated its fouling biota through integrative taxonomic approaches. Plastic pieces (82 %) with land-based origin (96 %) and limited sizes (10–20 cm) were the items most commonly encountered, suggesting a transfer to deep waters through floating and sinking. The majority of the items were not fouled, and the debris hosted an impoverished biota, leading to hypothesize that benthic litter supports wide communities only in shallow waters. Higher colonization rates were observed for gastropod and cephalopod eggs with no preference for materials and sizes, suggesting that even small pieces of soft plastic provide a spawning habitat for molluscs and affect species' connectivity in the deep-sea ecosystem. Holistic approaches are necessary to evaluate interactions between litter and biota. • The continental slope of the Gulf of Naples hosts a limited number of litter items. • Plastic pieces with land-based origin and limited sizes were commonly encountered. • The debris hosted an impoverished biota but supported molluscan spawning. • Higher colonization rates were observed for gastropod and cephalopod eggs. • Holistic approaches are necessary to evaluate interactions between litter and biota. [ABSTRACT FROM AUTHOR]

We investigate the 2013 Mw 7.5 Craig, Alaska, earthquake and nearby seismicity to understand better how temperature and composition may control the depth of seismic rupture along a strike-slip fault offsetting contrasting lithosphere types. The Queen Charlotte-Fairweather (QCF) fault lies between the oceanic lithosphere of the Pacific plate and the accreted Insular superterrane of the North American continent. We use point-source and finite-fault modeling of teleseismic body waves to characterize the focal mechanism and the depth extent of seismic rupture of five Mw 5.9-7.5 earthquakes. Four of the five earthquakes are consistent with rupture on the QCF fault. We find that these four earthquakes have centroid depths between 11 and 18 km (± 3 km) and aftershocks with an order of magnitude less than typical continental earthquakes. Finite-fault modeling of the 2013 Craig earthquake favors bilateral rupture along a 150 km fault with a depth range of slip between 5 and 25 km, with faster rupture (4-5 km/s) to the north than the south (1 km/s). These results suggest that the transition of brittle to ductile deformation along this section of the Pacific-North American plate boundary is thermally controlled by a more mafic rheology than average continental crust, exhibiting behavior consistent with that of an oceanic strike-slip fault. [ABSTRACT FROM AUTHOR]

The Queen Charlotte Fault (QCF) is a major strike-slip fault that forms the boundary between the Pacific and North American plates from 5 Io to 58° N. Near 53.2° N, the angle of oblique convergence predicted by the Mid-Ocean Ridge VELocity (MORVEL) interplate pole of rotation decreases from > 15° in the south to < 15° in the north. South of 53.2° N, the convergent component of plate motion results in the formation of a 40 km wide terrace on the Pacific plate west of QCF and earthquakes with thrust mechanisms (including the 2012 Haida Gwaii earthquake sequence) are observed. North of 53.2° N, in the primary rupture zone of the M 8.1 strike-slip earthquake of 1949, the linear terracc disappears, and topography of the continental slope west of the QCF is characterized by a complex pattern of ridges and basins that trend obliquely to the primary trace of the QCF. Deformation within the Pacific plate appears to occur primarily through strike-slip faulting with a minor thrust component on secondary synthetic faults. The orientations of these secondary faults, as determined from seismic reflection and bathymétrie data, are consistent with the reactivation of faults originally formed as ridge-parallel normal faults and as thrust faults formed parallel to the QCF south of the bend at 53.2° N and subsequently translated to the north. We suggest that an oblique convergence angle of 15° represents a critical threshold separating distinct crustal responses to transpression. This result is consistent with theoretical and analog strain models of transpressive plate boundaries. The shatpness of this transition along the QCF, in contrast to purely continental transform boundaries, may be facilitated by the relatively simple structure of oceanic crust and the presence of pre-existing, optimally oriented faults in the young Pacific plate. [ABSTRACT FROM AUTHOR]

To inform risk assessments, reliable, time efficient and affordable quantification methods are required for creating a microplastic (MP) pollution baseline in the world's oceans. To facilitate this, MP abundance was investigated in sediments of three contrasting areas of the UK continental shelf: North West of Jones Bank, the Canyons in the Celtic Sea and Dogger Bank in the North Sea, utilising the Nile Red tagging method to assess its time efficiency and cost. Average MP abundance in the top 10 cm was 1050–2700 MP kg−1. MP abundance decreased with increasing sediment depth and increased with increasing water depth. The findings emphasise the extent of MP pollution and illustrate the value of Nile Red for large scale mapping at relatively low cost. [Display omitted] • Three different areas of the UK continental-shelf were investigated for microplastics. • Microplastic abundance increases with water depth and decreases with depth into the sediment. • Microplastic abundance in UK sediments could be as high as 2700 MP kg−1. • Nile Red offers a rapid and low-cost approach to monitoring microplastics on a large scale. [ABSTRACT FROM AUTHOR]

The ecological preferences of living benthic foraminifera from the riverine influx dominated eastern continental margin of India have been studied. The living benthic foraminifera were abundant on the upper slope (~100–700 m). Three distinct species assemblages were identified. Assemblage 1 (Ammonia beccari , Pseudononion costiferum , Hanzawaia nipponica , Bolivina frondalis , Bolivina dilatata , Bolivina striatula , Asterorotalia milletti) representing warmer, well-oxygenated water and coarse substrate with low organic carbon is restricted to the inner shelf. Assemblage 2 includes species (Verneuilinulla propinqua , Ammodiscus incertus , Buliminella dubia , Rotaliatinopsis semiinvoluta , Bolivina lowmani , Fursenkoina spinosa) thriving in the regions with abundant food availability and low oxygen concentration on the continental slope. The species in Assemblage 3 (Globocassidulina subglobosa , Epistominella exigua , Gyroidinoides subzelandica , Reophax longicollis , Adercotryma glomeratum , Cystammina pauciloculata , Spiroplectammina biformis) prefer deeper waters with moderate organic carbon and dissolved oxygen. The information of the ecological niches of benthic foraminifera will help in environmental impact assessment and paleoecological studies. • Ecological preferences of living benthic foraminifera have been studied from the eastern continental margin of India. • Living benthic foraminifera are grouped into three distinct assemblages based on their ecological preferences. • Assemblage 1 represents shallow water depths and varying DO, temperature, coarse fraction, C org /N and salinity. • Assemblage 2 indicates high food availability and depleted DO on the continental slope. • Assemblage 3 indicates deeper waters with moderate organic carbon and DO. [ABSTRACT FROM AUTHOR]

A central objective of the Ross Sea region Marine Protected Area (MPA) is to protect areas important to the life cycle of Antarctic toothfish (Dissostichus mawsoni), a top fish predator and by far the region's most important commercial species. Juvenile toothfish predominate in deep basins along the inner continental shelf, whereas adults are found mostly along the continental slope and spawning areas on the Pacific-Antarctic Ridge. The inner basins connect to the continental slope via glacial troughs and predictable transport along each trough results in exchange with the Antarctic Slope Current as it flows westward. From the slope, two transport pathways, an eastern one from Iselin Bank and a western one that turns cyclonically along the flank of the Southeast Indian Ridge, connect northward to the Pacific-Antarctic Ridge, where the northern arm of the Ross Gyre and the Antarctic Circumpolar Current flow eastward. Using a circulation model to compare transport pathways connecting toothfish life history areas, we consider which inshore basins are likely most important in contributing to adult spawning aggregations; how transport pathways from each may be expected to influence distributions along the continental slope and Pacific-Antarctic Ridge; and how zonal transport pathways may promote export to areas downstream of the marine reserve. Although the MPA protects some critical life history pathways for toothfish, others remain vulnerable to commercial fishing, and we argue that those in adjacent areas along the Iselin Bank, Pacific-Antarctic Ridge and the Amundsen Sea might usefully be protected, discussing the range of policy instruments available. We also recommend consideration of transport pathways in deliberations for a proposed network of Southern Ocean MPAs, introducing a system-based tool using chemical tracers in otoliths that can test for toothfish movement between areas connected along the Antarctic Slope Current and Antarctic Circumpolar Current. [ABSTRACT FROM AUTHOR]

Anthropogenic debris has been reported in all studied marine environments, including the deepest parts of the sea. Finding areas of accumulation and methods of transport for debris are important to determine potential impacts on marine life. This study analyzed both sediment cores and Remotely Operated Vehicle video to determine the density and distribution of debris, including both micro- and macroplastics, in Norfolk and Baltimore canyons. The average microplastic density in Norfolk Canyon sediment was 37.30 plastic particles m−2 within the canyon and 21.03 particles m−2 on the adjacent slope, suggesting that microplastics could accumulate within submarine canyons. In video transects from both Norfolk and Baltimore canyons, the largest amounts of macroplastic were recorded near the canyon heads. Our findings contribute to a growing evidence base that canyons and their associated benthic invertebrate communities are important repositories and conduits for debris to the deep sea. • Canyons on the Western North Atlantic Margin contain both micro- and macroplastics. • Canyons can transport both organic materials and marine litter to the deep sea. • Canyons play an important role in funneling and dispersing debris in the deep sea. • Canyon sediments contain both microplastics and diverse infaunal invertebrates. • The largest amounts of litter in submarine canyons are found near the canyon heads. [ABSTRACT FROM AUTHOR]

Polybromodiphenyl ethers (PBDEs) in superficial sediments from the Gulf of Lion were studied. They were largely predominated by BDE 209 (98.7% of all PBDEs) indicating that the main source of these pollutants was the commercial mixture deca-BDE. This compound and the less brominated BDE exhibited a southwestward decreasing concentration gradient following the dominant marine currents and bottom relief, e.g. the Mud Belt, the submarine canyons and the Open Continental Slope. All PBDEs exhibited statistically significant correlations confirming the common origin. However, a progressive transformation of the dumped BDE 209 was identified showing a depletion paralleled by increases of the less brominated BDEs (from 8.6% to 22%). These less brominated compounds were accumulated at about 100–140km away from the Rhone prodelta, e.g. at the end of the submarine canyons, evidencing that these transformation compounds can be accumulated at long distances from the dumping sites in the marine system. [Copyright &y& Elsevier]

Abstract: Northern slope of the South China Sea is a potential area of gas hydrates and research focus areas. Analyzed geochemical parameters about pore water of the anions and cations of major components and δ13CDIC in the sediments from Shenhu sea area, Dongsha sea area and Southwest Taiwan Basin and collected by gravity piston. The results showed that Cl− concentration were no significant changes with depth at the three stations and their values were consistent with the normal sea water, SO4 2-concentration showed significant changes in gradient descent from core top to bottom at three stations and Ca2+, Mg2+, Ca2+/Mg2+ showed a similar downward trend with SO4 2− concentration, but the amplitude is inconsistent. The SMI of Shenhu sea area, Dongsha sea area, Southwest Taiwan Basin were separately 11m, 8m, 6m and δ 13CDIC of pore water in the sediments range from -10 ‰ to -27 ‰, which were similar with geochemistry characteristics of pore water in the sediments at other international regions of being found gas hydrate, such as Blake Ridge and Mexico Gulf. These geochemistry characteristics may suggest that natural gas hydrate reservoir released methane in deep sediments and methane was mixture gas as main causes of pyrolysis. Summary a series anomaly indicators and identification methods that use these geochemical anomalies characteristics about pore water of shallow sediments to trace gas hydrate in deep stratum. [Copyright &y& Elsevier]

Abstract: From January to February 2008 the training research vessel TRV Umitaka Maru conducted a comprehensive oceanographic survey of the waters around the 140°E meridian off Adélie Land as part of the Collaborative East Antarctic Marine Census (CEAMARC) project. The acoustic component of this survey was conducted using a scientific echosounder operating at 38 and 70 kHz to estimate the distribution and density of Antarctic krill (Euphausia superba) and ice krill (E. crystallorophias). In addition, the relationship between the vertical distribution of Antarctic krill and the water temperature structure along the 140°E meridian was investigated. Antarctic krill were distributed in the waters of the continental slope at 65–66°S and the maximum value of the mean areal density ρ in 1 nautical mile (nmi) intervals was 4344 inds. m−2. Ice krill were distributed in the neritic waters of the continental shelf to the south of the 66°S and the maximum ρ in 1 nmi intervals was 23,669 inds. m−2. Along the 140°E meridian, Antarctic krill were mainly distributed at the water temperatures below 0.5 °C. Although they were mostly distributed shallower than approximately 100 m, dense aggregations at approximately 180–200 m were also observed, which coincided with a depression of the water temperature structure. [Copyright &y& Elsevier]

Abstract: We report on the hydrographic observations collected on the Antarctic continental shelf between 138°E and 146°E as part of the CEAMARC and ALBION projects in December 2007–January 2008. A total of 140 quasi-synoptic CTD (Conductivity–Temperature–Depth) casts were analysed to map the spatial distribution of the summer hydrographic properties. Seven distinct hydrographic regimes were identified based on regional topographic features and the presence of specific water masses. These regimes are associated with spatial contrasts in the distribution of the High Salinity Shelf Water (HSSW) and the Modified Circumpolar Deep Water (MCDW). In particular, the HSSW distribution confirms the unique character of Commonwealth Bay in terms of extreme bottom salinity and dissolved oxygen values. The bay appears to be a preferred region for both dense shelf water formation and storage. The systematic survey of the Adélie Depression shows the ubiquitous presence of HSSW in the depression, and over the Adélie Sill as a 60 m thick layer at the centre of the sill. This water is dense enough to mix down the continental slope and form Antarctic Bottom Water. Upstream of the sill, the HSSW is shown to sit over the topography with indications of recirculation. The D’Urville Trough, another deep basin on the shelf, is filled with warmer and fresher water that is too light to contribute to the formation of AABW. The D’Urville Trough appears to collect MCDW which enters at the shelf break over the Adélie Bank and spreads over the northern slope of the trough. Another branch of MCDW enters in the eastern Adélie Sill and is found almost everywhere in the Adélie Depression with the noticeable exception of the coastal bays. Additional CTD casts collected during the ALBION-2009 experiment in January 2009 suggest that most of the features observed in 2008 in the Adélie Depression should be robust on a year-to-year basis although summer 2009 was characterized by fresher dense shelf waters. [Copyright &y& Elsevier]

Abstract: The distribution and community structure of euphausiids and the population structure of Euphausia superba were investigated mainly along 140°E off Adélie Land in the Indian Ocean sector of the Southern Ocean during the austral summers of 2003, 2005 and 2008. Euphausiids were collected from six discrete depth layers, primarily between 0 and 2000 m, using an RMT 8 net. Euphausia frigida and Euphausia triacantha mainly occurred north of the Southern Boundary of the Antarctic Circumpolar Current (SB) whereas E. superba was distributed south of the SB, and occurred abundantly in the continental slope area where Antarctic Winter Water was observed. E. frigida and E. triacantha occurred in the upper 200 m during the night whereas they were mainly found below 200 m during the daytime. Cluster analysis on stations suggested that the SB is an important biological boundary for euphausiid communities. The population structure of E. superba in 2003 was different from that of 2005 and 2008. While large mature individuals dominated in 2003, small immature krill (juveniles and subadult males) were more abundant in 2005 and 2008. Further sea-ice extension in the preceding winter in 2005 and 2008 likely provided favourable conditions for spawning and survival. A cluster analysis based on similarity of the maturity stages of E. superba revealed that mature males and gravid females (stage IIIC–E) were mainly distributed in the offshore area and mesopelagic zone, while juveniles and subadult males were found in the epipelagic zone of the continental slope area. Therefore, it is considered that E. superba migrates to the offshore area and mesopelagic zone as it grows. [Copyright &y& Elsevier]

Abstract: As marine debris levels continue to grow worldwide, defining sources, composition, and distribution of debris, as well as potential effects, becomes increasingly important. We investigated composition and abundance of man-made, benthic marine debris at 1347 randomly selected stations along the US West Coast during Groundfish Bottom Trawl Surveys in 2007 and 2008. Anthropogenic debris was observed in 469 tows at depths of 55–1280m. Plastic and metallic debris occurred in the greatest number of hauls followed by fabric and glass. Mean density was 67.1itemskm−2 throughout the study area but was significantly higher south of 36°00′N latitude. Mean density significantly increased with depth, ranging from 30itemskm−2 in shallow (55–183m) water to 128itemskm−2 in the deepest depth stratum (550–1280m). Debris densities observed along the US West Coast were comparable to those seen elsewhere and provide a valuable backdrop for future comparisons. [Copyright &y& Elsevier]

The article presents a study which investigates the zonation patterns of the macrofaunal assemblage with the interacting communities. It says that the change in faunal composition in depths suggests an underlying species replacement continuum without distinct boundaries identified. It explains that faunal change across continental slopes is considered as an environmental gradients. The study reveals the correlative approach in the macroecological relationship between depth, export particulate organic carbon (POC) flux and zonation of the macrofaunal community. It suggests that depth zonation cause is attributed to sunlight, temperature, pressure, water masses and food availability. It adds that there is a need to test parsimonious zonal thresholds for other continental margin ecosystems.

The article presents a study that evaluates the Octocorallia and Scleractinia fauna with regards to their spatial distribution and species association under the influence of water masses in Campos Basin. It mentions that octocorals and stony corals distributions and associations among taxa with water masses were analyzed in which complete dissimilarity was observed between the shallower depth range and middle depth. Result shows that lower slope area were more homogenous while middle slope areas were distinct from one another. It notes that the co-occurrence of octorals indicates the type of habitat and among these species which are indicative of cold-water reef environments include Paragorgia johnsonii, Corallium niobe, and Narella.

Abstract: Tectonics and petroleum potential of the underexplored East Arctic area have been investigated as part of an IPY (International Polar Year) project. The present-day scenery of the area began forming with opening of the Amerasia Ocean (Canada and Podvodnikov—Makarov Basins) in the Late Jurassic—Early Cretaceous and with Cretaceous—Cenozoic rifting related to spreading in the Eurasia Basin. The opening of oceans produced pull-apart and rift basins along continental slopes and shelves of the present-day Arctic fringing seas, which lie on a basement consisting of fragments of the Hyperborean craton and Early Paleozoic to Middle Cretaceous orogens. By analogy with basins of the Arctic and Atlantic passive margins, the Cretaceous—Cenozoic shelf and continental slope basins may be expected to have high petroleum potential, with oil and gas accumulations in their sediments and basement. [Copyright &y& Elsevier]

Copyright of Nova Acta Científica Compostelana is the property of Universidad de Santiago de Compostela, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nova Acta Científica Compostelana is the property of Universidad de Santiago de Compostela, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many important processes occur within the shallow section of the seafloor on the continental shelf and slope, yet conventional geophysical constraints on the physical properties within this critical boundary layer are limited. Some of the key constraints involve quantification of fluids within the seafloor, which can be provided by electrical methods. This paper reviews the application of a towed EM system to map the uppermost 20 m of seafloor in a variety of settings ranging from nearshore regions in water depths of approximately 10 m on the continental shelf out to water depths of 1300 m. The system is a mapping tool that provides areal maps of seafloor resistivity and has been used for a variety of purposes, including sedimentary characterization and facies mapping, evaluation of groundwater discharge, and mapping seafloor mounds in the Gulf of Mexico, thought to contain massive deposits of gas hydrate. [ABSTRACT FROM AUTHOR]

Provides information on a study that investigated the spatial or territorial connections between different species of bottom fishes on the shelf and continental slope of Guinea. Methodology of the study; Results and discussion on the study; Conclusion.

This work compares the numerical results of a three-dimensional hydrodynamic baroclinic model and a known analytical solution due to Baines of the baroclinic lunar semidiurnal (M2) tidal propagation over the continental shelf. The simplifying numerical approaches are the Boussinesq and the hydrostatic hypothesis. The hydrostatic pressure restricts the use of this model to every phenomenon associated with major vertical accelerations, as is sometimes the case of internal tides near steep slopes. A comparison between the two models in the area of the continental shelf was performed for 2.5, 5 and 10 per cent shelf slopes. The results obtained are the following: (a) the linear numerical solution approaches the analytical solution for these slopes, (b) the convection terms become significant for slopes greater than 5 per cent and (c) the non-linear numerical model becomes unstable for slopes above 10 per cent, therefore requiring non-hydrostatic pressure. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is an important environmental indicator of anthropogenic pollution. In this study, the Hg content in the bottom sediments of the East Siberian Sea was observed to range from 13 to 92 ppb, with an average of 36 ppb. Facies dependence was also observed and expressed as an increase in the Hg concentration in fine-sized sediments on the shelf edge and continental slope, compared to that in the sandy silts and sands of the inner shelf. The Hg accumulation in bottom sediments of the eastern part has increased over the past 150 years due to an increase in global emissions of anthropogenic Hg, which is caused by the transboundary transport of Hg to the Arctic. Moreover, changes in the Hg value, which occur due to the plankton arriving at the bottom sediments because of changes in hydrology and primary production, are thought to be associated with global warming. • At the first time, the Hg concentration in bottom sediments of the East Siberian Sea has been determined. • Hg content ranged 13–92 ppb with the background concentration of 36 ppb. • The bottom sediments had low ecological risk relatively Hg. [ABSTRACT FROM AUTHOR]

Copyright of Atmosphere - Ocean (Canadian Meteorological & Oceanographic Society) is the property of Canadian Meteorological & Oceanographic Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atmosphere - Ocean (Canadian Meteorological & Oceanographic Society) is the property of Canadian Meteorological & Oceanographic Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atmosphere - Ocean (Canadian Meteorological & Oceanographic Society) is the property of Canadian Meteorological & Oceanographic Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The abundance and composition of anthropogenic marine debris from 2012 to 2014 was assessed according to three bottom trawl surveys conducted on the upper continental slope between 198 m and 501 m off the Pacific coast of northeastern Japan. The surveys quantitated marine debris as follows: 33.52–164.62 items km−2 (January to July 2012), 91.68–215.11 items km−2 (November 2012 to May 2013), and 160.13–178.19 items km−2 (November 2013 to May 2014). Plastic bags or household materials mainly dominated terrestrial sources of debris. Principal component analysis latitudinally divided the study area according to debris abundance caused by geographical and hydrodynamic features. The long-term effect of tsunami-associated debris on the seafloor environment was recognized, because terrestrial sources such as heavy household materials were most abundant throughout the study period, with the additional accumulation of fishing gear and plastic bags. • Seafloor marine debris on the continental slope off northeastern Japan quantified. • Terrestrial marine debris dominated from 2012 to 2014. • Debris associated with the 2011 Tohoku earthquake and tsunami still abundant throughout study period. • Continuous increase in sea-based source fishing gear evaluated. • Increased continuous widespread accumulation of plastic bags implied. [ABSTRACT FROM AUTHOR]

The flapper skate, Dipturus intermedius (Parnell, 1837) , is the largest of all European skate and rays (Superorder: Batoidea). It is found in coastal waters of the European continental shelf and slopes in the North-East (NE) Atlantic. With the 2006 IUCN Red List of Threatened Species classification of 'common skate' as Critically Endangered, and the recognition in 2010 that this name masked two species (flapper skate and blue skate D. batis (Linnaeus, 1758)), and to better support conservation on this regional scale, the Flapper Skate Working Group (SWG) was formed. The SWG is a consortium of government, NGOs, sport-fishing associates and academics, including participants from the UK, Ireland and the Netherlands. The purpose of the SWG is to consolidate relevant research, advocacy and policy expertize for the purpose of flapper skate conservation. The first SWG workshop took place in Belfast, November 2019, with discussions focussed on conservation in the NE Atlantic. Following two days of talks, workshops and discussions, we present the SWG's key recommendations for future collaborative conservation. [ABSTRACT FROM AUTHOR]