Box Cores Research Articles

New species of Scalibregmatidae (Annelida) from slope and abyssal depths off eastern Australia

Seven new species of Scalibregmatidae are described from deep waters off the east coast of Australia. Samples were collected as part of the RV Investigator voyage IN2017_V03 in May/June 2017 using a Brenke sledge and 0.25 m2 box core. Sample depths reported in the present study were from the lower continental slope of about 2450 m to abyssal depths up to 4280 m. These collections provide the first scalibregmatid polychaetes to be described from deep water off Australia. The new species of Scalibregmatidae are in the genera Asclerocheilus (1), Axiokebuita (1), Oligobregma (4), and Pseudoscalibregma (1). Each of the new species is compared and contrasted with their known congeners. Asclerocheilus and Oligobregma are the largest genera of the family in terms of numbers of species; the known species of each of these genera are tabulated and compared. The Scalibregmatidae known from abyssal depths of about 3000 m and greater are reviewed and discussed.

New findings of the family Pardaliscidae from the deep-sea southwestern Atlantic: the genus Caleidoscopsis Karaman, 1974

Caleidoscopsis is a deep-sea pardaliscid genus known previously only from the SE Atlantic Ocean (Angola Basin), NE Pacific Ocean (Mexico, Cedros Trench) and Indian Ocean (Madagascar). This is the first record of Caleidoscopsis from off the Brazilian coast, SW Atlantic Ocean. Samples were collected with box core and/or van veen grabs between Espírito Santo, Campos and Santos Basin (19o-27o S), and around 417-1974 m depths. Two new species is herein described, Caleidoscopsis carlosi sp. nov., which differs from all Caleidoscopsis species by antenna 1 geniculate; maxilliped palp, article 4 shorter than 3; pereopods 5-7, propodus shorter than dactylus; and pereopod 7 with propodus 7x longer than wide; and Caleidoscopsis karamani sp. nov., which can be distinguished by rostrum more developed, reaching half-length of article 1 of peduncle of antenna 1; antenna 2, peduncle, article 5 longer than 3 and 4; pereopod 7, propodus 13x longer than wide, subequal to dactylus; urosomite 1 covering part of urosomite 2, with 1 long dorsal tooth; urosomite 2 with 1 very long and thin dorsal tooth almost reaching the end of urosomite 3. Further on, Caleidoscopsis carlosi sp. nov. turn out to be a very common and abundant species along the study area, being found in 126 samples with a total of 146 specimens examined, when comparing with C. karamani sp. nov. that was found in only 5 samples with one individual each. A table of comparison and an identification key of the currently six known species of the genus are provided. The present study is an effort in understanding and unrevealing the deep-sea macrofauna from the Brazilian margin bringing new data on the family Pardaliscidae found in the slope of the Campos, Santos and Espírito Santo Basins.

Macrofauna-sized foraminifera in epibenthic sledge samples from five areas in the eastern Clarion-Clipperton Zone (equatorial Pacific)

Benthic foraminifera cannot be sampled adequately using a single device. Smaller taxa are best collected using multicorers, the larger with box corers, but towed devices (dredges, trawls and epibenthic sledges) also retain many larger species. Here, we describe macrofaunal (>300 µm) foraminiferal assemblages obtained using an epibenthic sledge (EBS) in the Clarion-Clipperton Zone (eastern equatorial Pacific), a region hosting seafloor deposits of polymetallic nodules. Twelve EBS samples were collected in four areas licenced for exploration by the International Seabed Authority (ISA) to German, IOM, Belgium and French contractors, and to APEI-3, one of the protected Areas of Special Scientific Interest designated by the ISA. We recognised 280 morphospecies among 1954 specimens, with between 74 (IOM) and 121 (Belgium) in particular areas. Most (92.7%) were single-chambered monothalamids, of which 75 species (26.8%) belonged to the Komokioidea (‘komoki’), 47 (16.8%) to branched and unbranched tubes, 33 (11.8%) to chain-like and 32 (11.4%) to various ‘komoki-like’ forms. Fragments of megafaunal xenophyophores represented 21 species (7.50%), including Spiculammina delicata, previously reported only from the Russian area. Rarefaction curves and sample coverage completeness curves suggest that only a fraction of the macrofaunal foraminiferal diversity had been sampled. The occurrence of 71.8% of species in 1-2 of the 12 samples and 84.9% in 1-3 of the samples was a likely result of substantial undersampling. Dissimilarity in species composition between areas was very high: 64.2% (German vs IOM area) to 86.9% (German area vs APEI-3). Similarity within a single area was quite low: 29.1% (German) to 45.1% (IOM). In multidimensional scaling (MDS) plots, the APEI-3 area was clearly distinct in terms of faunal composition from all other areas, the French area somewhat separated from the German, IOM and Belgium areas, with the German and IOM samples being the most similar. These patterns may reflect the geographical separation of the French and APEI-3 areas and their location in deeper, more oligotrophic waters. Our study demonstrates that EBS samples from the eastern CCZ are a rich source of novel foraminiferal taxa, particularly light, easily resuspended komoki, providing a valuable perspective on foraminiferal biodiversity.

CAGE20-WORM Cruise Report: CAGE Worm-cruise to outer Kvalsund collecting tubeworms and sediment for eDNA and aDNA

From the morning of October 28th to the evening of October 28th 2020, fieldwork was performed comprising retrieval of live siboglinid worms for genetic and environmental studies hereunder pore water content of sulphate, sulphide and methane and sediment TOC, TC and isotopes. The working area was a basin located in outer Kvalsund, Troms, northern Norway. A total of 2 box core stations and 2 gravity core stations were obtained and two CTD casts. Echosounding and chirp data were recorded on stations and on transits. The cruise may be known as: CAGE20_WORM

The geochemistry of zinc and copper stable isotopes in marine hydrothermal brine pools: Perspectives from metalliferous sediments of the Atlantis II Deep, Red Sea

This study provides a zinc and copper stable isotope characterization (δ66Zn, δ68Zn, and δ65Cu) of metalliferous seafloor sediments from the Atlantis II Deep, a hydrothermally influenced brine basin in the Red Sea. Samples collected from box cores that capture the entire stratigraphy in the Deep have δ66Zn and δ65Cu values of −0.31 to 0.34 ‰ (0.02 ‰ median) and − 1.81 to 1.02 ‰ (−0.34 ‰ median) relative to the JMC-Lyon and NIST SRM 976 standards, respectively. These results suggest enrichments of light stable isotopes in sediments compared to the hydrothermal inputs to the basin, which likely overlap the mantle-like isotopic signatures of basalts beneath the Deep. Such shifts to lower δ66Zn and δ65Cu values are consistent with widespread metal sulfide deposition from the brines because sulfide anions preferentially consume the light stable isotopes of zinc and copper. However, this interpretation contrasts with observations in the open ocean, where the fractionation of zinc and copper stable isotopes is strongly influenced by biological utilization and organic matter. Previous studies proposed that metal deposition in the Atlantis II Deep is also driven by adsorption onto iron oxides/hydroxides and their weakly crystalline (Si-)Fe-OOH precursor phases within the brines. However, because this process should accumulate heavy zinc and copper stable isotopes, its influence on isotopic fractionation is likely limited. Controls by metal sulfide precipitation are also indicated by spatial covariations between δ66Zn and concentrations of zinc and copper, that is, δ66Zn values increase whereas metal contents decrease with distance away from hydrothermal venting. Comparable trends are lacking for copper isotopes, perhaps because of additional influence by redox processes or, compared to zinc, a much stronger influence by adsorption onto (Si-)Fe-OOH phases, particularly in areas distal to hydrothermal venting where reduced sulfur could be scarce. Collectively, our results from the Atlantis II Deep indicate that zinc and copper stable isotopes could provide information about base and precious metals deposits from similar paleoenvironments. Firstly, zinc and copper stable isotopes shed light on metal sourcing and accumulation processes. Secondly, mineral precipitation in hydrothermally influenced brine pools produces zinc stable isotope patterns that, at least theoretically, could be of interest in mineral exploration at sub-basin and deposit scales.

Macrofauna abundance and diversity patterns of deep sea southwestern Gulf of Mexico

The diversity and distribution of macrofaunal communities in the deep-sea bottoms of Gulf of Mexico (GoM) Mexican waters are poorly known compared to the northern GoM. This study was designed to contribute to the knowledge of macrofauna communities through (i) evaluate the taxonomic composition of macrofauna communities at major taxa level, and (ii) analyze the spatial distribution patterns in the deep sea of the southwestern GoM. Benthic macrofauna composition was analyzed in a large geographical area (92.67°–96.70° W 18.74°–23.04° N) and bathymetric gradient (185-3740 m depth). Samples were collected on board the R/V Justo Sierra (Universidad Nacional Autónoma de México) with a Reineck-type box corer during the oceanographic cruises SOGOM-3 and SOGOM-4 carried out on April 21–May 15, 2017, and on August 29–September 20, 2018, respectively. Thirteen environmental parameters were measured (among them, depth, salinity, temperature, O2, sediment grain size, hydrocarbons, and organic matter). Twenty-five taxa were registered in SOGOM 3 (2315 individuals) all of which were observed in SOGOM 4 (1721 individuals) with exception of the mollusk Class Solenogastres. The average abundance (ind. m-2) registered was 517 (range: 150-1388 ind. m-2), and 347 (range: 38-1088 ind. m-2) for SOGOM 3, and SOGOM 4, respectively. In SOGOM 3 Polychaeta, Nematoda, Amphipoda, Tanaidacea, and Bivalvia contributed with 75% of the total abundance, which were also the most abundant in SOGOM 4 representing 82% of total macrofauna abundance. Highest abundance was registered to the south of the study area near the coast, and the lowest one was found in deeper areas. Macrofauna abundance decreased with depth in both cruises. High diversity values were registered at intermediate depths in the south and west zones of the study area. Both cruises separated in a nMDS analysis. During SOGOM 3 dissolved oxygen, aromatic hydrocarbons, and organic matter (%) were the environmental variables related to macrofauna whereas, in SOGOM 4, depth was the most important one. This study fills a gap in the knowledge of diversity and distribution of macrofaunal communities of the deep-sea bottoms of a large area covering the whole bathymetric range of southern Gulf of Mexico and provides a baseline useful to compare with polluted areas and for assessing the impact of chronic pollution and/or potential oil spill accidents.

Soft-Bottom Infaunal Macrobenthos of the Avilés Canyon System (Cantabrian Sea)

The Aviles Canyon System (Northern Atlantic coast of Spain) is one of the ten marine regions studied in the Spanish seas by the LIFE+ INDEMARES project, which aims to identify special areas of conservation within the Natura 2000 Network. This study aims to characterize the composition and distribution of the macrobenthic fauna in order to provide baseline data to obtain a basic knowledge of the environment. Three oceanographic surveys were carried out to investigate species and habitats of this deep-sea ecosystem. The stations were sampled using a box corer, in order to evaluate the distribution and biodiversity of the macroinfauna, and to analyse the granulometric composition and the organic matter content. Sediments were mainly sandy in nature, the finest sediments with the highest organic matter content were found in the deepest areas, while coarser sediments were located in shallow stations. Polychaetes were the best represented group in total number of species and individuals, followed by crustaceans and molluscs. Five major macrobenthic assemblages were determined through multivariate analyses. Bathymetry and sedimentary composition were the main factors structuring the benthic community separating shallow and coarser stations from deeper and finer ones.

First record of the genus Harpinia Boeck, 1876 (Amphipoda: Phoxocephalidae: Harpiniinae) from the southern hemisphere, with description of three new species

ABSTRACT Three new species of Harpinia are described from north-eastern Brazil, documenting the first record of the genus from the southern hemisphere. The material examined was collected using a Mini Box Corer within the project ‘Avaliação da Biota Bentônica e Planctônica da Bacia Potiguar e Ceará’ in Potiguar Basin, Rio Grande do Norte state, from depths ranging from 283–998 m. Harpinia bidens sp. nov. is characterized by the following: head with dorsal keel; antenna 2 peduncle article 1 weakly ensiform; gnathopod 2 palm defined by a large excavation producing a spine; epimeral plate 1 posteroventral corner as a short blunt lobe; and epimeral plate 3 with an oblique facial row of setae, posteroventral corner as a large spine. Harpinia kingae sp. nov. can be diagnosed by the following: antenna 2 peduncle article 1 ensiform; gnathopod 1 palm defined by a u-shaped excavation; coxa 7 posterior margin crenulate; epimeral plate 3 posteroventral corner as a spine; and uropod 2 outer ramus with subapical nail. Finally, H. longidactyla sp. nov. has the following diagnostic characters: head with lower lateral blunt projection; antenna 2 article 1 not ensiform; gnathopods 1–2 palm defined by a sinuous excavation; pereopod 6 dactylus longer than propodus; and epimeral plate 3 posteroventrally rounded. Also, a discussion about the genus and an identification key to world species of Harpinia are provided.

Seasonal cruise Q4 2019

This cruise was the second of in total four seasonal cruises with RV Kronprins Haakon in 2019/20 focusing on biology in the project Arven etter Nansen (AeN). This seasonal cruise was named Q4 (Q4= 4th quarter of the year) investigating in total 17 stations of the established AeN transect along 34 E in the Northern Barents Sea and adjacent Arctic Basin from 76 to 82°N (see Fig. 1 below). The cruise addressed objectives of the research foci in RF1 on Physical drivers, RF2 on Human drivers, RF3 on the living Barents Sea and RA-C Technology and method development, and collected a multitude of data along the Nansen Legacy transect which was ice covered except the southernmost station P1. In addition to in situ sampling, on board experiments were conducted to quantify biological processes, rates and interactions that will also be important feeds into modeling work and projections in RF4 The future Barents Sea.
 The cruise took a variety of continuous ship measurements (Weather station, EK80, EM203, ADCP, thermosalinograph, pCO2 underway) as well as station measurements such as CTD with water samples, biological sampling of the benthos (box corer, benthic trawl), water column (multinet, MIK net, macrozooplankton trawl and many other smaller nets) and sea ice (snow, ice cores, water just underneath sea ice). In addition, experimental work (respiration, grazing and egg production) was conducted in the ship’s laboratories. The chemistry team onboard measured oxygen, nutrients and pH from standard depths on most CTD stations and sea ice samples.
 The cruise started in Longyearbyen and ended in Tromsø (28.11.-17.12.2019). The sampling began at the deep (>3000 m) northernmost station of the transect, Stn. P7, and continued along the southward transect until station P1, in open water and Atlantic dominated water masses. During the expedition the Barents Sea was characterized by a relatively large sea ice cover with consolidated sea ice all the way from P7 to P2. The Polar Front was located just north of P1. All process stations were sampled (P7-P1) as well as two ice stations: one close to P7 ad one close to P5. At the southernmost station P1, stormy weather challenged sampling, but most tasks were in the end accomplished except of deploying the box corer, sediment trap and the AUV. These operations were considered too challenging due to strong drift and ship movement, and it was not safe to conduct small boat operations. Challenges with the box corer was also experienced at the deep station P7 due to technical issues. In the end, most work was accomplished despite challenging weather, sea ice conditions and some technical issues making this cruise successful in gaining new important knowledge about the Northern Barents Sea in the polar night season which is extremely poorly studied. The overall high biological activity and biomass at this time of the year, November-December, was surprising for most of us.

Macrobenthic diversity response to the atlantification of the Arctic Ocean (Fram Strait, 79°N) – A taxonomic and functional trait approach

This is the first study presenting temporal changes of the macrofauna biodiversity along the bathymetric gradient from the shelf to abyssal depths in the eastern Fram Striat. In this region, between 2004 and 2008, a significant increase in surface water temperature was observed due to the transport of Atlantic water from lower latitudes and was defined as a Warm Water Anomaly (WWA). Effects of the WWA in the eastern Fram Strait were observed across the entire food web, from the pelagic to the deep seafloor. The material for our study was collected before (in 2000) and after the WWA (in 2010 and 2017) at station depths ranging from 203 m to 5561 m. Samples of macrofauna and surface sediments were collected with use of a box corer to analyze species composition and functional traits, and environmental characteristics in sediments. We explore the influence of environmental changes on the structure (species composition and diversity) and functioning (functional trait composition and diversity) of macrofauna communities. An increase of primary production in surface waters during and after the WWA was reflected in a higher food availability at the seafloor from shelf to abyssal depths. Warming induced environmental changes led to an increase of macrofauna density and taxonomic diversity at all water depths. Macrofauna species composition significantly changed after the WWA. At all study sites, macrofauna functional diversity increased after the warm period. Functional trait composition changed significantly along the bathymetric transect. Despite changes in the taxonomic composition, macrofauna communities at the shallowest stations showed high functional redundancy, i.e., trait composition remained unchanged after the WWA. At water depths below 1500 m, where functional redundancy was significantly lower, functional trait composition changed significantly after the WWA. Our results suggest that macrofauna communities on the shelves are more resistant to environmental changes compared to deep-sea assemblages in the eastern Fram Strait.

Physical properties of Quaternary sediments from the western South Korea Plateau, East Sea

Sediment samples were collected with a piston sampler (114 samples) and a box core sampler (266 samples) during research cruises on the R/V Tamhae 2 of the Korea Institute of Geoscience and Mineral Resources (KIGAM) from 2015 to 2019, to examine the characteristics of seafloor sediments from the western South Korea Plateau of East Sea. The in situ velocity was measured at four sites using a seafloor acoustic probe developed by KIGAM (KISAP). The samples were analyzed for their physical properties and the resulting data were examined to gain insights into the distribution patterns of the sediments and how the physical properties varied by burial depth. The actual velocity of the seafloor sediments was investigated by comparing the velocities in the laboratory and in situ velocity measurements at four sites. Overall, the physical properties agree well with the expected characteristics of marine sediments but there is considerable variation in the mean grain sizes. The sediment distributions either increases or decreases gradually with depth, reflecting transport from topographically high areas (e.g., possible source and/or shelf areas). The relationships between the physical properties of samples from two transects, one east-west and the other south-north, are different, and reflect the presence of tephra with a low grain density at the specified depth intervals. The laboratory velocity is higher (approximately 20–40 m/s) than the in situ velocity measured by the KISAP because of differences in the temperature (approximately 22 °C) and pressure (∼100 atmospheric pressure). However, the corrected laboratory velocity agrees well with the in situ velocity. Inconsistencies in the data, such as the measurement frequency and condition of each system, measurement interval, and sediment grain size, are probably responsible for some of the variations in the physical property data.

Influence of Chemoautotrophic Organic Carbon on Sediment and Its Infauna in the Vicinity of the Rainbow Vent Field

Hydrothermal vents have been recognised as isolated islands of productivity in the deep sea, but very little is known about the transport and export of chemoautotrophic produced organic carbon to vent surrounding habitats. Here, we investigate vent carbon export and its influence on benthic food webs in sediments at the Rainbow (RB) vent field at the Mid Atlantic Ridge in ~2200 m water depth. Two sites were considered along the dispersal direction of the RB vent plume for sample collection: the close vicinity at about ~30-100 m (“near-vent”); and at 4 km distance (“off-vent”) to the nearest venting area. At both sites, box corers were used to sample sediments and their fauna. A turbidity sensor mounted on a CTD/Rosette provided data on the presence of a vent fluid plume in the water column. Niskin bottles were used to sample suspended particulate organic matter (SPOM) from the plume, as well as from surface waters at 75 m depth. SPOM, sediments and fauna were analysed for nitrogen and carbon stable isotopes. Carbon derived from in situ chemoautotrophy, characterised by depleted δ13C, was taken up by infauna close to the venting area as the main nutrition source, while fauna at the off-vent site showed less depleted δ13C with a signature more typical for photosynthetic- derived material. Nematodes were the most abundant faunal taxon. Their abundance and biomass were variable and not different at the two studied sites. In situ derived organic matter was traced back in the food web in the close vicinity of the venting area. The connectivity of vent and non-vent habitats should be taken appropriately into account when designing future spatial management plans with regard to deep-seabed mining at hydrothermal vents.

Discovery of a large offshore population of the northeast Pacific burrowing shrimp Neotrypaea sp. (Decapoda: Axiidea)

The burrowing ghost shrimp Neotrypaea californiensis and Neotrypaea gigas, are recognized primarily from soft-sediment intertidal mudflats of estuaries and coastal lagoons in the northeastern Pacific from southern Alaska to Baja California. Individual records, however, are also known from occasional deep-water offshore collections. In previous offshore grab samples from California to Washington, USA, Neotrypaea spp. were present in about 14% of stations between 20 and 130 m depth. We assumed these usually low density (1–2 per core) small individuals were errant settlers from estuarine sources until summer 2019 when we found the first known large multi-year class population in an area 58–77 m deep 12 km offshore of Newport, Oregon, USA. The newly discovered Neotrypaea population, that we tentatively identify as Neotrypaea gigas, occurred at 35 of 52 stations (67%) in densities up to 26 individuals per 0.1 m2 box core and included multiple size classes. Plan view camera samples indicate burrow densities of over 400 openings m−2. This is the first report of a major burrowing shrimp population on the continental northeast Pacific coastal ocean.

Avilés Canyon System: Increasing the benthic biodiversity knowledge

Macro and megafauna were studied in the Avilés Canyon System (ACS), southern Bay of Biscay (Cantabrian Sea), during several oceanographic cruises carried out from 2009 to 2017. The biodiversity of ACS is summarized and its description is herein updated after sampling surveys of several programmes (ECOMARG, INDEMARES, SponGES, INTEMARES) conducted by the Spanish Institute of Oceanography (IEO).This study has updated previous knowledge in the canyon area from past national and international projects, their reports and publications as well as data collected in the context of regional projects designed to gain new insight into the diversity of marine invertebrates and fishes from the ACS. Samples were taken using a range of sampling gears (Rock dredge, Beam trawl, Trawl gear GOC-73, Suprabenthic sledge, Box corer and Remoted operated vehicle), from 55 to 2291 m in depth. A total of 1015 species were identified at the ACS: 98 Porifera, 153 Cnidaria, 14 Brachiopoda, 22 Bryozoa, 97 Mollusca, 151 Annelida, 315 Arthropoda, 74 Echinodermata and 91 Chordata. New records for the Bay of Biscay fauna include 13 Porifera species, 17 Cnidaria, 7 Mollusca, 8 Arthopoda, 3 Echinodermata and 4 Chordata. Also the bathymetric range of some species has been extended. As a result of the research projects carried out in the area in the last fifteen years, important information is now available which suggests that the ACS houses a large number of species with a high ecological value, that it represents a biodiversity hotspot in terms of the presence of sponge aggregations and coral reefs in certain regions, and that it sustains important fisheries due to the abundance of comercial species. Given the relevance of the species and habitats occurring in the ACS, there is a need to implement a conservation and management plan of the area in order to maintain habitats in good state of preservation.

Age-Heterogeneity in Marine Sediments Revealed by Three-Dimensional High-Resolution Radiocarbon Measurements

Marine sedimentary archives are routinely used to reconstruct past environmental changes. In many cases, bioturbation and sedimentary mixing affect the proxy time-series and the age-depth relationship. While idealized models of bioturbation exist, they usually assume homogeneous mixing, thus that a single sample is representative for the sediment layer it is sampled from. However, it is largely unknown to which extent this assumption holds for sediments used for paleoclimate reconstructions. To shed light on 1) the age-depth relationship and its full uncertainty, 2) the magnitude of mixing processes affecting the downcore proxy variations, and 3) the representativity of the discrete sample for the sediment layer, we designed and performed a case study on South China Sea sediment material which was collected using a box corer and which covers the last glacial cycle. Using the radiocarbon content of foraminiferal tests as a tracer of time, we characterize the spatial age-heterogeneity of sediments in a three-dimensional setup. In total, 118 radiocarbon measurements were performed on defined small- and large-volume bulk samples ( ∼ 200 specimens each) to investigate the horizontal heterogeneity of the sediment. Additionally, replicated measurements on small numbers of specimens (10 × 5 specimens) were performed to assess the heterogeneity within a sample volume. Visual assessment of X-ray images and a quantitative assessment of the mixing strength show typical mixing from bioturbation corresponding to around 10 cm mixing depth. Notably, our 3D radiocarbon distribution reveals that the horizontal heterogeneity (up to 1,250 years), contributing to the age uncertainty, is several times larger than the typically assumed radiocarbon based age-model error (single errors up to 250 years). Furthermore, the assumption of a perfectly bioturbated layer with no mixing underneath is not met. Our analysis further demonstrates that the age-heterogeneity might be a function of sample size; smaller samples might contain single features from the incomplete mixing and are thus less representative than larger samples. We provide suggestions for future studies, optimal sampling strategies for quantitative paleoclimate reconstructions and realistic uncertainty in age models, as well as discuss possible implications for the interpretation of paleoclimate records.

Description of a novel genus with three new species of Phoxocephalidae G. O. Sars, 1891 (Crustacea: Amphipoda) from off northeastern Brazil.

Magnaphoxus ajaja gen. et sp. nov., Ma. simplex gen. et sp. nov. and Ma. longicarpus gen. et sp. nov. are described. The material examined was collected off the states of Cear, Rio Grande do Norte and Bahia during the projects Avaliao da Biota Bentnica e Planctnica na poro offshore das Bacias Potiguar e Cear (BPOT) and Programa de Avaliao do Potencial Sustentvel de Recursos Vivos na Zona Econmica Exclusiva (REVIZEE). Additionally, material from other surveys off Brazilian northeastern coast is included. The samples were collected by rectangular dredges, box corer and Van Veen grabs, ranging from shallow waters to 168 meters in depth. The new genus is morphologically similar to the genera Grandifoxus Barnard, 1979, Metharpinia Schellenberg, 1931, Microphoxus Barnard, 1960 and Rhepoxynius Barnard, 1979. However, it can be recognized by the exclusive constricted and very broad rostrum and bilobated coxa 6, plus the combination of characters such as: lower lip outer plate with apical cusps; right mandible without lacinia mobilis; pereopods 34 carpus posterior margin with one distal robust long seta; propodus strongly armed with robust setae; uropods 12 peduncle dorsolateral margin combed distally; telson with two apical robust setae on each side. All three new species, are fully described, illustrated, and discussed.

Diversity and Zonation of Benthic Amphipod Crustaceans Affected by the Mississippi Submarine Canyon in the Northern Gulf of Mexico

Amphipod crustacean diversity and zonation are described from the large Mississippi Canyon that extends from the continental shelf across the entire continental margin. Benthic amphipods were sampled on four cruises from 2000 to 2004 from six locations in the Mississippi Canyon from depths of 480 through 2,750 m, and compared with five locations in a second transect on the open continental slope approximately 100 km west of the canyon to assess the canyon effect on the structure and composition of amphipod assemblages. Five replicates were collected from each location using 0.2 m–2 GOMEX box corer. Amphipods amounted to 40% of the total faunal abundance within the canyon compared to only 4% in the non-canyon samples. Of the seventy-two species (19 families) collected, 61 were encountered in the canyon compared to 38 on the non-canyon transect. The trough-like head of the canyon (480 m) supported high densities (4,446–26,933 ind./m2) of the filter feeding, tube dwelling ampeliscid amphipod (Ampelisca mississippiana), the highest densities sampled compared to any other single species, at any other location, either within or outside the canyon, reflecting extreme flux of organic detritus from the continental shelf. The dominance by this single species suppressed the within – habitat (alpha) diversity and evenness, compared to relatively high diversity within the 1,000–1,500 m depths interval both in and outside the canyon. The species richness and alpha diversity exhibited mid-depth maxima at ca. 1,100 m both in and out of the canyon. High species richness (61) over the entire length of the canyon is presumed to be a function of greater topographic complexity and intermittent mass wasting of sediment down the canyon axis. The absence of nestedness is attributed to the amphipod reproductive pattern that lacks dispersive larval stages and brooding comparatively small numbers of eggs in this taxon. Despite depressed diversity at the head of the canyon, the fact that the number of amphipod species in the Mississippi Canyon was 1.5 times their numbers on the adjacent slope suggests that this physiographic feature enriches geographic-scale species diversity.

Sedimentary Anthropogenic Carbon Signals From the Western Pacific Margin for the Last Century

The declining trend of the δ13C of tropical corals over the last century was about −0.01‰ year−1, according to global coral records. The decrease was attributable to the significant input of anthropogenic CO2 (13C Suess effect) to the atmosphere. Previous studies of δ13C in corals suggested that the signal of the anthropogenic carbon in the Pacific and Indian Oceans were weaker than that in the Atlantic Ocean. However, biases relating to environments in which corals grew caused concerns. To investigate the anthropogenic carbon signal in the Western Pacific, foraminiferal records in a suite of 13 box cores with good age control were obtained from the continental slope off southwestern Taiwan between 2004 and 2006. δ18O values of planktonic foraminifera (Globigerinoides sacculifer or so-called Trilobatus sacculifer) in collected cores were relatively stable at −2.5‰ to −2‰ in the last century, but foraminiferal δ13C had a gradual secular decline after the 1900s. The decline trend of δ13C began to intensify after the 1960s, and its rate was similar to that observed in the Atlantic. Similar decline trends of δ13C were also found in coral records at regions where the human activity is high (Liuqiu) and low (Dongsha). Our findings indicate that the anthropogenic carbon signal in the Western Pacific was not weaker than that recorded in the Atlantic, and the nearshore sediment can supplement the lack of δ13C records in corals, which are deficient when the environment is not suitable to grow.

Macrofaunal Distribution, Diversity, and Its Ecological Interaction at the Cold Seep Site of Krishna-Godavari Basin, East Coast of India.

Cold seeps are characterized by typical endemic communities with associated microorganisms that depend on sulfide, methane, reduced nitrogenous compounds, and metals as electron donors for their survival through chemosynthesis. The discovery of an active cold seep site in January 2018 in the Krishna-Godavari (K-G) basin of Bay of Bengal was followed by a transit cruise in March 2018 to investigate the distribution and diversity of macrofauna. Further, the ambient sediment and pore water biochemistry were estimated to understand its relationship with macrofauna and the microbial associates of the sediment. Samples were collected at a water depth of around 1750m at 3 stations: SP1, SP2, and SP3, using the box corer. The benthic fauna at the sites consisted mainly of Bivalvia, shrimps of Caridea family, Gastropoda species, Malacostraca species, Polychaeta, and few species of Echinoidea, Ophiuroidea, and Echiura. A total of 2313 macrofaunal individuals belonging to 8 classes, 18 families, and 20 species were identified from all the three stations. The communities were diverse at these sites with an average Shannon diversity index of 1.64 and are closely related to the lineages previously studied in ecologically similar environments. Most of the macrofauna were found to be filter feeders preferring a low organic carbon environment. Relict vesicomyid clams at the present study site suggest the succession from vesicomyids to the present composition of bivalve mussels and siboglinid worms. The microbial associates in the sediment significantly correlated with methane and hydrogen sulfide concentrations. The study suggests that the K-G basin cold seep serves as a conducive environment for the flourishing of benthic communities and therefore can support a rich biodiversity.

Macrobenthic assemblages across deep-sea pockmarks and carbonate mounds at Santos Basin, SW Atlantic

The SE Brazilian continental margin is rich in geomorphological features that create different seascapes, where diverse benthic communities thrive. The seafloor is composed of a mixture of pockmarks of different sizes and shapes and tall carbonate mounds that may form extensive chains. Mounds are colonized by deep-water corals which are the main responsible organisms promoting growth over geological time. Depressions and mounds affect the benthic ecosystem in multiple ways owing to water flow, sedimentation rates and food availability. This paper presents new data on macrofaunal composition and community structure associated with deep-sea coral habitats and pockmark areas along the upper continental slope of Santos Basin. Ten sites were sampled using a 0.25 m2 box corer on board R/V Alpha-Crucis, totaling 27 sediment samples. A total of 182 taxa were found, including new records for the Southwestern Atlantic, as well as several potential new species to science. In general, we observed an association of the macrobenthic fauna with the geomorphology of the area and the most important variables, mainly substrate composition and water flux. The abundance, taxonomic composition and also the feeding modes varied across the deep-water coral sites and pockmarks, reflecting in a mosaic of benthic habitats. As deep-sea corals and pockmarks are extremely sensitive to anthropogenic influence and natural shifts, in addition to the economic value associated to fisheries, this study provides baseline information on these special habitats in Santos Basin that can be used for future research, monitoring activities, and conservation strategies.