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

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,

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

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 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

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

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. Gigantidas vrijenhoeki n. sp.

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

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

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

Despite the ecological importance of deep-sea cephalopods, little is known about their genetic diversity or population dynamics. The cephalopod species Cranchia scabra, Pyroteuthis margaritifera, and Vampyroteuthis infernalis are commonly collected in midwater samples from both the Gulf of Mexico and northwestern Atlantic Ocean but, despite their common appearance in trawls and important roles in marine

Cobalt-rich ferromanganese crusts on seamounts have attracted much attention due to high economic potential of various metals. Studies showed that seamounts in the Western Pacific Ocean are rich in cobalt-rich crusts, and Weijia Guyot (Ita Mai Tai) is one of the most promising one. Cobalt-rich crusts were drilled from this seamount in our previous investigation. This study evaluates promising areas

Earthquakes can significantly impact ecosystem function and survivability of marine organisms, however their effect on marine predators remains unknown. In November 2016, a 7.8 magnitude earthquake triggered a ‘canyon flushing’ event in the submarine canyon of Kaikōura (New Zealand), a year-round foraging ground for sperm whales (Physeter macrocephalus). Underwater landslips and turbidity currents

We investigate ventilation in the South China Sea (SCS) based on a recently developed framework for annual subduction/obduction in monsoon-dominated oceans. It is found that subduction occur in winter, and it was greatly weakened by ~58% due to the summer monsoon. Furthermore, there is a second obduction window opened up during the summer monsoon period, besides the winter obduction window. The winter

In the present study, current effects on waves (CEW) in a strong western boundary current area is investigated. An analytical formula is first derived to address how the kinematic parameters of currents affect wave variations: strain rate, divergence and deformation rate. The formula is applied to numerical wave solutions in the East China Sea (ECS), where the Kuroshio flows through. It is found that

Deep-sea corals (DSCs) are important living marine resources, forming both oases of biodiversity and three-dimensional habitat structure for fishes and invertebrates. However, because of logistical difficulties and expense of deep-sea exploration, much less is known about the distribution of DSCs than is known for their shallow-water counterparts. Predictive modeling, therefore, is essential for estimating

Deep-sea sediments are populated by diverse microbial communities that derive their nutritional requirements from the degradation of organic matter. Extracellular hydrolytic enzymes play a key role in the survival of microbes by enabling them to access and degrade complex organic compounds that are found in seafloor sediments. Despite their importance, extracellular enzymatic activity is poorly characterized

This study describes a method to quantify the chemical composition of deep-sea hydrothermal deposits in situ using laser-induced breakdown spectroscopy (LIBS). Partial least squares (PLS) regression analysis is applied to spectra obtained using a long laser pulse with a duration of 150 ns. The number of measurements needed to address the spatial heterogeneity of samples is determined through high-resolution

For vocal animals with distinctive calls, passive acoustic monitoring can be used to infer presence, distribution, and abundance provided that the calls and calling behaviour are known. Key to enabling quantitative acoustic surveys are calibrated recordings of identified species from which the source parameters of the sounds can be estimated. Obtaining such information from free-ranging aquatic animals

Diel vertical migration (DVM) is normally limited to the upper 1000 m. However, the use of ship-borne and stationary submerged echosounders in the Red Sea unveiled consistent formation of daytime patches extending to 1200-1300 m, the patches dissolving at night when individuals migrated shallower. The diel vertical migration was not synchronized, and in the evening 4–5 h passed from the first to the

This study investigates the evolution of deep-sea lebensspuren assemblages before, during, and after five high-energy episodes over a storm-events period lasting 25 days. Bioturbational changes were characterized through brief benthic storm events in the northeastern Pacific at the abyssal time-series site Station M (4000 m depth). Quantification of seafloor coverage was processed to evaluate variations

The hadal zone (from 6 to 11 km depth) is one of the least explored habitats on Earth, and the knowledge about trophic ecology of hadal organisms is limited. Here, we analyzed fatty acid biomarker and stable isotope ratios of the amphipod species (Alicella gigantean) collected in the New Britain Trench (8225 m depth) in the southwestern Pacific Ocean. A total of 50 samples were divided into five developmental

This study provides estimates of the mean eddy-induced diffusivities of passive tracers in a three-layer, double-gyre quasigeostrophic (QG) simulation. A key aspect of this study is the use of a spatial filter to separate the flow and tracer fields into small-scale and large-scale components, and we compare results with those obtained using Reynolds temporal averaging. The eddy tracer flux is related

The Southern Ocean is a vast net sink for atmospheric carbon dioxide (CO2), with marine phytoplankton playing a crucial role in CO2 fixation. We assessed how changes in the dominant phytoplankton community and net primary productivity (NPP) affected variations in the partial pressure of CO2 in surface water (pCO2sw) in the Indian sector of the Southern Ocean during austral summer. pCO2sw was negatively

Recent culture studies of living coccolithophores have established a biogeochemical framework for the use of the geochemical compositions of their calcite biominerals as proxies in palaeoceanography. Yet, questions remain regarding the transferability of such experimental data to fossil coccoliths. Here we analysed the carbon and oxygen isotopic composition of Miocene coccoliths to assess the suitability

The distribution and transport of paralarvae of the complex Sthenoteuthis oualaniensis - Dosidicus gigas (SD complex, Cephalopoda: Ommastrephidae) in the tropical-subtropical convergence off Mexico were analyzed under contrasting interannual environmental conditions. Two El Niño years were sampled (2010 and 2016), in which the SST were up to 3 °C above the average throughout the study area, while during

The abyssal and hadal Buccinoidea from the north-western Pacific formerly attributed to the genera Tacita and Calliloncha were analyzed for the first time using both multilocus molecular and morphological data. The results allow re-evaluation of the inter- and intrageneric variability of morphological characters and demonstrate that Tacita, Calliloncha and Paracalliloncha are synonyms of Bayerius,

In deep-sea environments, which have low densities of large benthic animals, meiofauna are a useful indicator of biodiversity. However, in low-latitudes and in low-productivity areas, meiofaunal density is low, but is higher than that of megafaunal or macrofaunal density. Therefore, it is difficult to collect a sufficient number of specimens for statistical analysis. In addition, because faunal classification

Sperm whales live in culture-based multilevel societies in which the fundamental social level is the nearly permanent social unit of females and immature individuals, and the largest level is the clan constituted by social units that share a common coda repertoire. This study describes the coda repertoire and vocal clans of sperm whales in Brazilian waters recorded between 2011 and 2016. Inter-click

During an expedition in 2012 we recovered sediment, water, and biological samples from the inner slope of the Mariana Trench using a lander equipped with cameras, three twenty-liter Niskin bottles, a baited net trap, and a pressure calibrated depth sensor. Images and samples collected from the 10,677 m drop site reveal filamentous structures covering both talus and outcrop, which we cautiously identify

The inner ear structure of Antimora rostrata and its coupling to the swim bladder were analyzed and compared with the inner ears of several shallow-water species that also have similar coupling. The inner ear of Antimora has a long saccular otolith and sensory epithelium as compared to many other fishes. Some parts of the membranous labyrinth are thick and rigid, while other parts are thinner but attached

Compilations have been made of sulfate reduction rates and oxic respiration rates over the entire range of marine sedimentation rates, and sedimentary environments, including several euxinic sites. These data show, consistent with the findings of Jorgensen (1982, Nature, 296, 643-645), that sulfate reduction and oxic respiration oxidize equal amounts of organic carbon in nearshore sediments. As sedimentation