The earliest evidence of deep-sea vertebrates.

Vertebrate macroevolution has been punctuated by fundamental habitat transitions from shallow marine origins to terrestrial, freshwater, and aerial environments. Invasion of the deep sea is a less well-known ecological shift because of low fossilization potential and continual loss of abyssal fossil record by ocean floor subduction. Therefore, there has been a lack of convincing evidence of bottom-living vertebrates from pre-Paleogene deep seas.

Microbiomes of Hadal Fishes across Trench Habitats Contain Similar Taxa and Known Piezophiles.

Hadal snailfishes are the deepest-living fishes in the ocean, inhabiting trenches from depths of ∼6,000 to 8,000 m. While the microbial communities in trench environments have begun to be characterized, the microbes associated with hadal megafauna remain relatively unknown. Here, we describe the gut microbiomes of two hadal snailfishes, (Mariana Trench) and (Kermadec Trench), using 16S rRNA gene amplicon sequencing.

Capillary absorption spectroscopy for high temporal resolution measurements of stable carbon isotopes in soil and plant-based systems.

Capillary Absorption Spectroscopy (CAS) is a relatively new analytical technique for performing stable isotope analysis. Here, we demonstrate the utility of CAS by recording and quantifying variation in C in controlled and biologically relevant applications. We calibrated CAS system response to increased CO, with an observed ∼4‰ increase in measured ΔC for each 0.

sp. nov. (Crustacea: Amphipoda) exhibits ontogenetic vertical stratification across abyssal and hadal depths in the Atacama Trench, eastern South Pacific Ocean.

S.I. Smith in Scudder, 1882 (Crustacea: Amphipoda) are prevalent scavengers of the benthopelagic community from bathyal to hadal depths.

On the regeneration of fish scales: structure and mechanical behavior.

Fish scales serve as a dermal armor that provides protection from physical injury. Owing to a number of outstanding properties, fish scales are inspiring new concepts for layered engineered materials and next-generation flexible armors. Although past efforts have primarily focused on the structure and mechanical behavior of ontogenetic scales, the structure-property relationships of regenerated scales have received limited attention.

New species of Eurythenes from hadal depths of the Mariana Trench, Pacific Ocean (Crustacea: Amphipoda).

Eurythenes S. I. Smith in Scudder, 1882 are one of the largest scavenging deep-sea amphipods (max.

Depression chains in seafloor of contrasting morphology, Atacama Trench margin: a comment on Marsh (2018).

This comment presents acoustic and visual data showing deep seafloor depression chains similar to those reported in Marsh ( 5: 180286), though from a different deep-sea setting. Marsh present data collected during cruise JC120 from polymetallic nodule rich sites within the Clarion-Clipperton Fracture Zone (CCFZ), at water depths of between 3999 and 4258 m. Within this comment, we present data collected with equivalent acoustic and imaging devices on-board the RV Sonne (SO261-March/April 2018) from the Atacama Trench, approximately 4000 m depth, which shows comparable depression chains in the seafloor.

Microplastics and synthetic particles ingested by deep-sea amphipods in six of the deepest marine ecosystems on Earth.

While there is now an established recognition of microplastic pollution in the oceans, and the detrimental effects this may have on marine animals, the ocean depth at which such contamination is ingested by organisms has still not been established. Here, we detect the presence of ingested microplastics in the hindguts of Lysianassoidea amphipod populations, in six deep ocean trenches from around the Pacific Rim (Japan, Izu-Bonin, Mariana, Kermadec, New Hebrides and the Peru-Chile trenches), at depths ranging from 7000 m to 10 890 m. This illustrates that microplastic contaminants occur in the very deepest reaches of the oceans.

Bathyal and abyssal demersal bait-attending fauna of the Eastern Mediterranean Sea.

Baited cameras were deployed over a depth range of 532-5111 m in the Ionian Sea to characterise the large mobile fauna. The planned installation of a neutrino telescope also offers the potential for biological observatories. The current study was intended to aid observatory placement.

Distribution, composition and functions of gelatinous tissues in deep-sea fishes.

Many deep-sea fishes have a gelatinous layer, or subdermal extracellular matrix, below the skin or around the spine. We document the distribution of gelatinous tissues across fish families (approx. 200 species in ten orders), then review and investigate their composition and function.

The limiting layer of fish scales: Structure and properties.

Unlabelled: Fish scales serve as a flexible natural armor that have received increasing attention across the materials community. Most efforts in this area have focused on the composite structure of the predominately organic elasmodine, and limited work addresses the highly mineralized external portion known as the Limiting Layer (LL). This coating serves as the first barrier to external threats and plays an important role in resisting puncture.

sp. nov.: A newly-discovered hadal snailfish (Scorpaeniformes: Liparidae) from the Mariana Trench.

Pseudoliparis swirei sp. nov. is described from 37 individuals collected in the Mariana Trench at depths 6898-7966 m.

Baited camera survey of deep-sea demersal fishes of the West African oil provinces off Angola: 1200-2500m depth, East Atlantic Ocean.

Deep-sea demersal fish surveys using baited cameras were undertaken in the West African oil provinces between 1297 m and 2453 m depth in 2002, 2005 and 2008. A total of 29 deployments amounting to 16,175 images encountered 31 species of bait attending deep-sea fish from 17 families. The extrapolated species richness was 34, indicating that the survey encountered over 90% of bait attending fish species in this area.

The natural armors of fish: A comparison of the lamination pattern and structure of scales.

Fish scales exhibit a unique balance of flexibility, strength and toughness, which is essential to provide protection without encumbering locomotion. Although the mechanical behavior and structure of this natural armor are of recent interest, a comparison of these qualities from scales of different fish species has not been reported. In this investigation the armor of fish with different locomotion, size and protection needs were analyzed.

Mercury concentrations in Pacific lamprey (Entosphenus tridentatus) and sediments in the Columbia River basin.

The accumulation of mercury was investigated in Pacific lamprey and stream sediments in the Columbia River basin. Mercury concentrations in larval lamprey differed significantly among sample locations (p < 0.001) and were correlated with concentrations in sediments (r  = 0.

The unique chemistry of Eastern Mediterranean water masses selects for distinct microbial communities by depth.

The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages.

Vulnerability of larval and juvenile white sturgeon to barotrauma: can they handle the pressure?

Techniques were developed to determine which life stages of fish are vulnerable to barotrauma from expansion of internal gases during decompression. Eggs, larvae, and juvenile hatchery-reared white sturgeon (Acipenser transmontanus; up to 91 days post hatch; d.p.