Pelagic polychaetes collected in the deep Arctic Ocean between 2011 and 2016 during three expeditions of R/V Polarstern were investigated using morphological taxonomic and molecular methods based on DNA sequences for portions of the mitochondrial 16 S and nuclear 18 S and 28 S rDNA genes. A comparison of our results on arctic Pelagobia cf. longicirrata Greeff1879, (Lopadorrhynchidae) and Typhloscolex

Shifts in phenology – annually occurring life history events – have been observed among many marine organisms due to global warming. We examined if phenological changes in the pteropod (pelagic snail) Limacina helicina antarctica have occurred along the Western Antarctic Peninsula, one of the most intensely warming regions on Earth, which would have important implications for regional food web dynamics

Recent advancements in deep-sea expeditions have made possible to sample adequate quantities of deep-sea organisms over wide geographical ranges for population genetic studies. Scalpellum stearnsii is a common stalked barnacle that occurs in the mesobenthic environment (>200 m depth) throughout the West Pacific Ocean and covers several major deep-sea basins. The present study examined the diversity

Distinguishing regions based on the geographic distribution of both abiotic factors and living organisms is an old but still actual central issue for biogeographers. In the Southern Ocean, the few existing regionalization studies have been carried out either at very large scales or on the relatively small region around the Sub-Antarctic islands of Kerguelen and the Crozet archipelagos. However, regionalization

Larval fish have been shown to vertically migrate with ontogeny, a behaviour that influences their dispersal by exposing the larvae to currents with different velocities at different stages of development. Most studies have focused on studying the vertical migration of tropical reef fishes, that have been shown in general to migrate downwards with ontogeny. Here we investigated if similar ontogenetic

Bernasconiaster pipi gen. et sp. nov. is described from work carried out in deep waters off Argentina. It is a small species with six arms, which has only cross-type pedicellariae, among other particular characteristics. Some specimens were found brooding their offspring in the oral area with their arms arched. Up to seven different stages of development were observed, each located at a particular

Fish sounds are important components of Azorean soundscapes. Therefore, unraveling their patterns can contribute to a better assessment of local biodiversity dynamics. Passive Acoustic Monitoring (PAM) is a cost-effective, non-intrusive method providing long-term information regardless of weather or logistic conditions, which can be especially useful when monitoring remote areas. Using PAM, we assess

Hadal trenches house distinct ecosystems but we know little about their sources of nutrition or trophic structures. We evaluated megafaunal food web structure and nutritional sources in the Kermadec and Mariana trenches using carbon and nitrogen stable isotope analysis (δ15N and δ13C values) of bulk tissues and proteinaceous individual amino acids (AAs). In the Kermadec Trench, bulk δ15N values ranged

Total alkalinity (AT) is one of four measurable cornerstone parameters for characterizing the marine carbonate system, yet its measurement by standard titration methods is subject to systematic misinterpretations in the presence of uncharacterized dissolved organic molecules in ocean and estuarine waters. A consequence of these misinterpretations may be the lack of thermodynamic consistency that is

Many foraging fishes spend their vulnerable life stages with low food availability in the oligotrophic Kuroshio. Although they are likely dependent on microbial production as their energy source, there is limited knowledge of the trophodynamics of the planktonic food web in the Kuroshio of the East China Sea (ECS-Kuroshio). Here, we demonstrate energy sources and feeding impacts of microzooplankton

Deep-sea coral communities are poorly known in the Southwestern Atlantic (SWA), particularly in the equatorial/subequatorial latitudes embraced by the northeastern Brazilian Exclusive Economic Zone (EEZ). Such knowledge gap has lead to the idea that the latter has low species richness when compared to southern Brazilian regions. Recent studies, however, indicate the northeastern slope as highly suitable

Here we present the results from a shotgun sequencing effort on foot tissues from a deep-sea hydrothermal vent endemic limpet. We present the complete mitochondrial genome of the hydrothermal vent endemic gastropod Peltospira smaragdina (Gastropoda, Peltospiridae) is presented here for the first time. This species is characteristic of circa-Azores hydrothermal vent ecoregion and provides a candidate

The Mediterranean is a semi-enclosed sea, with a narrow natural connection —the Strait of Gibraltar— through its western basin to the North Atlantic. Many studies have investigated how the inflow of North Atlantic Surface water into the Mediterranean shapes the faunal composition and abundance of the shallow-water benthic communities of the Western Mediterranean. However, the reverse effect remains

Specialist fauna populations from chemosynthetic ecosystems are connected through larval stages travelling in current highways in the vast deep sea. One shrimp family of such specialists, Alvinocarididae, is hitherto known to be endemic to vents and seeps with no reported occurrence in ephemeral organic-rich chemosynthetic habitats. Here we report the first occurrence of Alvinocaris muricola on experimentally

The first direct observations of the diversity and density of benthic epifauna from hadal depths was reported in 1965 from depths of 7300 m in the Puerto Rico Trench. The most striking part of the report from was an account of observing 200 snailfish (Liparidae) during a one mile transect by the bathyscaphe Archimède - an extraordinarily high-density of fish for hadal depths. In 2019 the submersible

Hydrocarbon seepage in cold seeps provides an appropriate environment for chemosynthetic communities to arise and for authigenic carbonates to form. To study the relationships between the chemosynthetic communities and underlying authigenic carbonates, extensive in situ Raman measurements were conducted on the fluids, chemosynthetic communities, and authigenic carbonates found at the Formosa Ridge

We found that the Hu et al. model for light scattering by pure seawater [Deep Sea Research Part I, 146, 103–109 (2019)] can be applied to waters with sub-zero temperature, which was outside the applicable range of the original equation for the refractive index of water that is used in the model. The surface waters with temperature < −1 °C in the Arctic Ocean and surrounding the Antarctic exhibit the

Argo float trajectory data has been used to estimate the velocities of mid-depth (1000 db) currents in the North Indian Ocean (NIO). The structure of the upper ocean absolute geostrophic currents can be derived more accurately from the Argo temperature and salinity profiles by referring to the estimated velocities rather than by assuming a level of “no motion”. The derived flow field reveals that the

We examined the distribution and feeding habits of the diel vertical migratory myctophid Myctophum orientale in the Kuroshio region of the western North Pacific in late winter. All 1985 specimens collected were in the juvenile stage, with a mean standard length (SL) of 29.9 mm. They occurred on the onshore side of the Kuroshio axis along the slope region off Japan, showing a typical pseudoceanic distribution

While reproduction in deep-sea corals remains incompletely understood, there is a particularly crucial shortage of information related to corals living in deep waters of the Arctic Ocean. In the present study, colonies of the deep-sea pennatulacean coral Umbellula encrinus were collected in Baffin Bay (High Canadian Arctic) at bathyal depths between 2006 and 2010. From examination of gamete sizes,

Intraspecific genetic differentiation reflects processes that underpin biodiversity in deep-sea habitats. We examined the spatial genetic structure of epibenthic amphipod taxa from upper bathyal depths (200–1200 m) along New Zealand's continental margins. Genetic variability in amphipods was assessed using cytochrome c oxidase I (COI) to characterise inter-regional diversity and phylogeographic patterns

Zooplankton diel vertical migration (DVM) during summer in the polar oceans is presumed to be dampened due to near continuous daylight. We analyzed zooplankton diel vertical distribution patterns in a wide range of taxa along the Western Antarctic Peninsula (WAP) to assess if DVM occurs, and if so, what environmental controls modulate DVM in the austral summer. Zooplankton were collected during January

The Western Isoguchi Jet, a quasi-stationary baroclinic jet that separates from the Kuroshio Extension, has been detected for a decade. Here we report the first observations of the vertical structure and temporal variations of the jet via moored current meters (September 2011–September 2012) and intensive hydrographic measurements (September 2010, 2011, and 2012). The jet flows northeastward and supplies

Bathymodiolus Kenk and Wilson, 1985 includes fourteen currently recognized species from deep-sea chemosynthetic environments in the Pacific, Atlantic, and Indian oceans. In this study, phylogenetic analyses of mytilid mussels sampled from seeps along the Costa Rica margin reveal the presence of three new Bathymodiolus species, sampled from depths across ∼1000–1900 m. Bathymodiolus billschneideri n

During the North Atlantic Bloom Experiment (NABE) of the Joint Global Ocean Flux Study (JGOFS), water column sampling for particulate and dissolved 210Po and 210Pb was performed four times (26 April and 4, 20, 30 May 1989) during a month-long Lagrangian time-series occupation of the NABE site, as well as one-time samplings at stations during transit to and from the site. There are few prior studies

The Zapiola Anticyclone (ZA) is a strong, O(100 Sv), barotropic vortex in the center of the Argentine Basin that is tied to a bathymetric feature called the Zapiola Rise. It is regionally significant for two reasons: first, the strong vortex is a dynamical barrier that inhibits the lateral exchange of water, and hence has the ability to trap water for a long period of time. Second, its dynamics is

Using high-resolution measurements of the Gulf Stream North Wall (GSNW), we investigated whether detachments from the warm current at the edge of the front, known as streamers, affect the overall heat and salt content of the region. Temperature, salinity, and velocity data were collected across the front from towed CTDs, shipboard ADCPs, and gliders following a Lagrangian drifter that was deployed

Deep-sea ecosystems are highly sensitive to changes in organic matter export and oxygenation driven by climate change. Here we document past ecological changes in benthic foraminiferal assemblages indicative of deglacial changes in deep-sea oxygenation and the character of organic matter fluxes from sedimentary records retrieved at intermediate (692 m) and abyssal (3667m) depths in the Gulf of Alaska

Food availability is a primary factor determining species distribution and success, especially for offshore benthic organisms that rely on sinking particles as their main food supply. Temporal changes in the quantity and quality of food sources, often linked to shifts in the prevailing hydrographic conditions, thus have important consequences for benthic community composition and ecosystem functioning

Cold-water corals (CWC) are known to be deep-sea biodiversity hotspots, yet there is still a huge knowledge gap regarding their associated fauna. As so, CWC ecosystems pose as a perfect environment for the discovery of new species. In this context two new species of Hamigera (Demospongiae) have been recorded associated with CWC in antipodal parts of the world: Hamigera bibiloniae sp. nov. from the

Sea-level fluctuations exert a major influence on deep-water depositional processes through changing sediment supply and oceanographic processes. By utilizing the bathymetric map and six piston cores (P1 and P5–P9) from the two major canyon systems (i.e., Pearl River Canyon (PRC) and Shenhu Submarine Canyon Group (SSCG)) within the Baiyun Sag, northern South China Sea (SCS), this study investigated

We examined primary production (PP) and the assimilation rates of nitrate (ρNO3-), ammonium (ρNH4+) and dinitrogen (ρN2) using 13C and 15N tracer techniques along bay to offshore transects in the Oyashio-Kuroshio-Tsugaru Warm Current interfrontal region in the northwestern North Pacific Ocean, during five research cruises covering a full seasonal cycle. Surface inorganic N was depleted in the bays

The bathypelagic zone is a large, dark, cold, high-pressure environment that undergoes extensive material and energy exchanges with the upper ocean and the deep biosphere. Viruses are important parts of the deep ocean, and transportation of surface viruses has been considered as an important source of deep-sea viruses. However, limited information is available about the activity and decay of surface

Embryonic development is a vulnerable and key period during the life cycle of an oviparous elasmobranch. Captivity studies are difficult to carry out on non-coastal species; hence, embryonic development can be analysed from samples collected from the seabed. Here, embryonic development of three shelf and deep-water skates from the southwest Atlantic Ocean, Bathyraja brachyurops, B. macloviana and Amblyraja

Submarine turbidity currents are one of the most important sediment transfer processes on earth. Yet the fundamental nature of turbidity currents is still debated; especially whether they are entirely dilute and turbulent, or a thin and dense basal layer drives the flow. This major knowledge gap is mainly due to a near-complete lack of direct measurements of sediment concentration within active submarine

The Sea of Marmara hosts part of the North Anatolian Fault as an active submarine strike-slip fault. This area has suffered numerous earthquakes and presents a major seismic risk. Although the Sea of Marmara has been studied for many years, the link between geological morphostructures, the nature of fluids and biological communities is still rarely described. During the Marsite cruise (November 2014)

Acoustic data are invaluable information sources for characterizing the distribution and abundance of mid-trophic-level organisms (micronekton). These organisms play a pivotal role in the ecosystem as prey of top predators and as predators of low-trophic-level organisms. Although shipboard-ADCP (acoustic Doppler current profiler) acoustic backscatter signal intensity cannot provide an absolute biomass

During two expeditions to seamounts near the Mariana Trench in the tropical western Pacific, several trochiform shells from the upper bathyal zone were sampled. Morphological observations of these specimens suggest that they represent two new species that belong to the family Trochidae, but the shell morphology, radular plan, and external anatomy differ considerably from those of closely related genera

Characterizing the patterns of stable carbon (δ13C) and nitrogen (δ15N) isotopes at the base of the food webs (baseline) is essential in ecological studies for assessing the feeding habits and migration patterns of marine predators. We analysed δ13C and δ15N in zooplankton samples collected in spring and autumn (2012–2015), along the south (SCM) and southeast (NCSM) Brazilian oceanic waters. An increase

Several species of deep-diving odontocetes, including beaked whales, sperm whales and pilot whales, are associated with steep continental slope habitat in the northeast Atlantic, where they feed on cephalopods and meso-bathypelagic fish. Some species such as sperm whales are listed as vulnerable by the IUCN red list, whilst many beaked whale species are listed as data deficient, therefore, understanding

Predicting the impacts of anthropogenic disturbance on deep-sea ecosystems requires a thorough understanding of both environmental and faunal drivers of ecosystem function. Studies of deep-sea ecosystems, however, typically consider environmental drivers only and seldom investigate the effects of seabed communities on ecosystem processes. Here, we describe spatial and temporal variation in sediment

A wintertime net sampling and hydrographic survey was conducted in the Kuroshio Extension (KE) and northern subtropical gyre during 3 cruise-legs in January–March 2006. Conductivity-Temperature-Depth (CTD), expendable CTD (XCTD) and expendable bathythermograph (XBT) surveys were conducted to examine the regional hydrographic structure, which included a distinct KE front water mass boundary, low-salinity

Submarine canyons are often morphologically complex features in the deep sea contributing to habitat heterogeneity. In addition, they act as major conduits of organic matter from the shallow productive shelf to the food deprived deep-sea, promoting gradients in food resources and areas of sediment resuspension and deposition. This study focuses on the Baltimore and Norfolk canyons, in the western North

Identifying the drivers that shape the biodiversity of a region is important to predict the response of ecosystems to environmental changes. Macrofaunal distribution pattern in the North Indian Ocean has so far been mainly studied considering small geographical areas, and using taxonomic diversity. The present study is a functional trait based approach aimed to identify the environmental drivers of

Benthic megafauna in deep-sea ecosystems with and without methane seeps in the South China Sea were quantified during 2013–2016. In total, more than 190 taxa were identified. Stable isotopic analyses (δ13C, δ15N) on the tissues of these megafauna were used to provide complementary data to reveal their trophic relationships. Ecopath models were constructed to show the flow of matter within deep-sea

The present study represents the first documentation of the trophic spectrum of the deep-water teleost fish Helicolenus dactylopterus in two basins of the central Mediterranean (Northern Ionian and Southern Adriatic) and the first attempt to compare the diets of this deep-water teleost fish between two different habitats: flat muddy seabed and cold-water coral (CWC) habitat. 346 stomachs were collected

The ecology of vertically migrating mesopelagic micronekton is affected by physical properties of their environment. Increased light attenuation in particle-rich productive waters, as well as low oxygen conditions decrease the migration amplitude. This likely has implications on the trophic organisation of micronekton communities, which are predominantly governed by niche partitioning in the vertical

We describe a new vent mussel species, Gigantidas vrijenhoeki n. sp., from material collected at a depth of 2022 m in the newly discovered Onnuri Vent Field (OVF) during the 2018 expedition to the Central Indian Ridge. This large modioliform mussel thrives around diffusive vents in aggregation with another dominant hydrothermal vent mussel, Bathymodiolus marisindicus. G. vrijenhoeki n. sp. was distinguished

The present study questions the ability of marine fauna to modulate the molecular composition of their membrane lipids, as a function of environmental hydrostatic pressure conditions. Specific variations in the cell lipidome composition are presented for the deep-sea hydrothermal vent shrimp Mirocaris fortunata, acclimated at the laboratory for several months at both natural (18 MPa) and atmospheric

Deep-sea scleractinian corals are distributed from 50 m to 6000 m depths. Under global environmental changes (e.g., ocean acidification) and anthropogenic effects (e.g., bottom trawling), deep-sea scleractinian coral assemblages are considered to be at great risk of losing fitness by allocating increased energy toward calcification. For marine organisms, population persistence and species resilience

Deep-sea corals are an important component of benthic ecosystems, but are potentially very vulnerable to ecological disturbance due to their extreme longevity and slow growth rates. Among the slowest growing genera are the ‘Black Corals’ (Family Antipatharia), which can have lifespans of millennia. The waters around New Zealand contain a variety of black corals, including species that grow at shallow

Albacore tuna (Thunnus alalunga) is a highly economically important species in the western Indian Ocean. However, knowledge of its ecological and nutritional characteristics, essential for proper management of the species, is lacking in the region. The trophodynamics of the Indian Ocean albacore was thus examined using known fatty acid trophic markers (FATMs) of primary producers, nutritional condition

Benthic communities in the deep sea are often characterized by high diversity, contrary to the once held view of the deep sea as an environment desolate of life. Heightened commercial interest in polymetallic nodule mining in the abyssal Clarion-Clipperton Fracture Zone (CCFZ) have seen a number of exploratory expeditions to the area. However, macrobenthic community structure is still poorly characterized

Hydrography in the Gerlache and Bismarck straits is described based on data collected in Januaries of 2015 and 2017, during austral summer. These straits are in the northern Antarctic Peninsula (NAP) continental shelf. In the study area, temperature in the surface mixed layer during January 2017 was warmer than recorded in other years, contemporaneous with an extreme decrease in Antarctic sea ice extent

The biogeography of the deep-sea benthic fauna is uncertain due to the vast size and incomplete exploration of these environments. While shallow water assemblages are differentiated into tropical, temperate and polar faunas, it is unknown whether these units extend to lower depths. Here we use model-based and multivariate statistics to analyse megafaunal benthic samples along a 2300 km transect off

This paper details the development and application of a new serial sampler capable of acquiring multiple deep-sea gas-tight fluid samples. It consists of a custom-made multiport sampling valve with six sampling cylinders distributed around it in a circle. The serial sampler can operate on the seabed to depths of 7000 m. Each cylinder has a sampling volume of about 160 ml and can maintain the sample

EM122 multibeam backscatter data acquired from the Caiwei seamounts and the deep-sea basin to its west in the western Pacific Ocean, is used to identify the distributions of ferromanganese nodules with different abundance, cobalt-rich crusts, pelagic calcareous and clay sediments, etc. Box and drill sample and video are used for ground truth. The backscatter data are processed by CARIS HIPS&SIPS 11

Microeukaryotes are mainly composed of highly diverse and abundant protists, whose diversity and distribution in deep oceans have not been well studied. We investigated the vertical profiles of microeukaryotes throughout the water column down to abyssal sediments and their horizontal distribution over a distance of 1,300 km in the Western Pacific Ocean, using high throughput DNA sequencing. A distinct