Guidelines for species descriptions of free-living aquatic nematodes: characters, measurements and their presentation in taxonomic publications.

Free-living aquatic nematodes are abundant, diverse and of general environmental importance. However, knowledge of species distributions of both marine and freshwater nematodes is sparse. Species distribution data are crucial for evaluating environmental impacts from human activities and to conduct integrated nematode community assessments.

Assessment of potential toxic elements in soils, sediments, and vegetation in the surroundings of Anapa, Russia.

The study presented here reports the concentration of major, trace, and rare earth elements in soil, sediments, and vegetation samples collected from 13 locations around Anapa City located on the northern coast of the Black Sea in Russia. The neutron activation analysis technique has been used to fulfill this objective. Along with this, the bioconcentration and translocation factors were calculated.

A note on the silent decline of the Caspian environment.

The Caspian Sea, the world's largest enclosed water body, experiences significant transformations in its physico-chemical properties and a decline in bioresources due to extensive anthropogenic activities. These activities include the discharge of diverse pollutants and bio-physical alterations such as over-fishing, hunting, and physical alterations to rivers. While acute manifestations such as a fall in the Caspian water levels and wetland desiccation are more overt, the pervasive impact of human activities contributes to a likely irreversible decline in environmental quality that we aim to spotlight in this discussion in order to facilitate its restoration.

Effect of a generalist mesopredator on modular and unitary sessile prey associated with a foundation species.

Unitary and modular sessile organisms both dominate in marine benthic communities, commonly preyed upon by the same generalist predators. The differences between unitary and modular defensive strategies may underlie the ways generalist predators control community structure, but this has never been empirically examined. We hypothesize that the individual size of an omnivorous mesopredatory shrimp affects the relative vulnerability of unitary and modular prey and hence translates into community structure.

Introduction to "Sixty Years of Modern Tsunami Science, Volume 2: Challenges".

Fifteen papers are included in this PAGEOPH topical issue "Sixty Years of Modern Tsunami Science, Volume 2: Challenges." The issue starts with a general introduction, and then briefly summarizes all contributions, first papers addressing general topics, and then articles grouped on a regional basis: Northern Pacific, Southeast Pacific, Southwest Pacific and Indonesia, and Mediterranean regions.

A new species of the grenadier genus Coelorinchus (Gadiformes: Macrouridae) from the western Indian Ocean.

A new species, Coelorinchus tricristiger sp. nov., is described from the western Indian Ocean off Socotra and Somalia.

Five new species of black coral (Anthozoa; Antipatharia) from the Great Barrier Reef and Coral Sea, Australia.

We describe five new species of black corals from the Great Barrier Reef and Coral Sea, collected at depths ranging from 14 to 789 m: two in the family Antipathidae (Antipathes falkorae sp. nov. and Antipathes morrisi sp.

A new species of the grenadier genus Coelorinchus from the seamounts in the southeastern Atlantic Ocean, with redefinition of C. vityazae (Teleostei: Gadiformes: Macrouridae).

Re-investigation of the grenadier Coelorinchus vityazae endemic to the West Wind Drift Islands Province reveals species-level differences between the populations from the southeastern Atlantic and southwestern Indian oceans. The southeastern Atlantic populations (from Discovery and Gough seamounts) are described as a new species, C. inventionis sp.

Climate change drives rapid decadal acidification in the Arctic Ocean from 1994 to 2020.

The Arctic Ocean has experienced rapid warming and sea ice loss in recent decades, becoming the first open-ocean basin to experience widespread aragonite undersaturation [saturation state of aragonite (Ω) < 1]. However, its trend toward long-term ocean acidification and the underlying mechanisms remain undocumented. Here, we report rapid acidification there, with rates three to four times higher than in other ocean basins, and attribute it to changing sea ice coverage on a decadal time scale.

A new species of Bathysphyraenops from the Indian Ocean with comments on the genus (Teleostei: Acropomatiformes: Howellidae).

A new species, Bathysphyraenops radhae, is described from the equatorial western Indian Ocean. It resembles Bathysphyraenops declivifrons in the shape of snout and number of pseudobranchial filaments in adults but can be readily distinguished from all known members of Howellidae by its characteristically armed preopercle and in strong reduction or absence of spinules on scales around the pectoral fin. The genus Bathysphyraenops is rediagnosed, and the characteristics useful in diagnosing the howellid genera are briefly discussed.

Sensory cells and the organization of the peripheral nervous system of the siboglinid Oligobrachia haakonmosbiensis Smirnov, 2000.

Background: The nervous system of siboglinids has been studied mainly in Osedax and some Vestimentifera, while data in Frenulata - one of the four pogonophoran main branches - is still fragmentary. In most of the studies, the focus is almost always on the central nervous system, while the peripheral nervous system has traditionally received little attention. In contrast to other annelids, the structure and diversity of sensory structures in siboglinids are still quite undescribed.

Description of a new and widely distributed species of (Cnidaria: Anthozoa: Antipatharia: Schizopathidae) previously misidentified as Brook, 1889.

For many years an undescribed species of the genus has been misidentified as Brook, 1889 (a species currently re-assigned to the genus ). This new species is rather common at mid- and lower bathyal depths of the Pacific, Atlantic and Indian oceans, often in areas with high concentrations of commercially valuable cobalt-rich ferromanganese crusts, where it was observed in underwater photo and video transects to occur in high densities. Under the name this species is recorded in several inventories and databases.

Delayed Antarctic sea-ice decline in high-resolution climate change simulations.

Despite global warming and Arctic sea-ice loss, on average the Antarctic sea-ice extent has not declined since 1979 when satellite data became available. In contrast, climate model simulations tend to exhibit strong negative sea-ice trends for the same period. This Antarctic sea-ice paradox leads to low confidence in 21st-century sea-ice projections.

New species of deep-sea Antipatharians from the North Pacific (Cnidaria: Anthozoa: Antipatharia), Part 2.

Five new species of deep-sea antipatharian corals are described from the North Pacific primarily collected off the coast of Alaska and on adjacent seamounts. All the species are referred to the family Schizopathidae. Described as new are: Alternatipathes mirabilis, Bathypathes ptiloides, Bathypathes tiburonae, Bathypathes alaskensis, and Parantipathes pluma.

Two rare species of Danielsseniinae (Copepoda: Harpacticoida: Pseudotachidiidae) from the Kara and East Siberian Seas, with description of their previously unknown sexes.

The previously unknown females of Danielssenia spitsbergensis Gee Huys, 1994 and males of Mucrosenia kendalli Gee Huys, 1994 (Pseudotachidiidae, Danielsseniinae) are described based on specimens collected in the Kara and East Siberian Seas. Females of D. spitsbergensis exhibit the main diagnostic features of the genus Danielssenia Boeck, 1873 (antennule four-segmented; proximal segment of antennary exopod with one seta; structure of all the mouthparts; absence of an inner seta on exopod-1 of P2P4; P5 not fused medially and with distinct exopod and baseoendopod, the latter with five setae; genital field with small copulatory pore and short copulatory duct leading to seminal receptacle with paired anterior chambers).

Revision of the Laonice bahusiensis complex (Annelida: Spionidae) with a description of three new species.

The morphological reexamination of specimens previously identified as Laonice bahusiensis Sderstrm, 1920 from North European and Mediterranean collections, supported by the molecular analysis of freshly collected material, enabled the recognition of four different species in the region: the genuine L. bahusiensis, L. irinae n.

Solitonic model of the condensate.

We consider a spatially extended box-shaped wave field that consists of a plane wave (the condensate) in the middle and equals zero at the edges, in the framework of the focusing one-dimensional nonlinear Schrodinger equation. Within the inverse scattering transform theory, the scattering data for this wave field is presented by the continuous spectrum of the nonlinear radiation and the soliton eigenvalues together with their norming constants; the number of solitons N is proportional to the box width. We remove the continuous spectrum from the scattering data and find analytically the specific corrections to the soliton norming constants that arise due to the removal procedure.

Insights into the structure and morphogenesis of the giant basal spicule of the glass sponge Monorhaphis chuni.

Background: A basal spicule of the hexactinellid sponge Monorhaphis chuni may reach up to 3 m in length and 10 mm in diameter, an extreme case of large spicule size. Generally, sponge spicules are of scales from micrometers to centimeters. Due to its large size many researchers have described its structure and properties and have proposed it as a model of hexactinellid spicule development.

Prolonged Siberian heat of 2020 almost impossible without human influence.

Unlabelled: Over the first half of 2020, Siberia experienced the warmest period from January to June since records began and on the 20th of June the weather station at Verkhoyansk reported 38 °C, the highest daily maximum temperature recorded north of the Arctic Circle. We present a multi-model, multi-method analysis on how anthropogenic climate change affected the probability of these events occurring using both observational datasets and a large collection of climate models, including state-of-the-art higher-resolution simulations designed for attribution and many from the latest generation of coupled ocean-atmosphere models, CMIP6. Conscious that the impacts of heatwaves can span large differences in spatial and temporal scales, we focus on two measures of the extreme Siberian heat of 2020: January to June mean temperatures over a large Siberian region and maximum daily temperatures in the vicinity of the town of Verkhoyansk.

Ecological risk simulation assessment in marine ecosystems of the Arctic shelf.

This work elaborates an approach to the ecological risk model assessment in marine systems exposed to intense impacts and accompanying pollution. This approach was applied to the marine ecosystems of the Arctic shelf for two types of ecosystems, i.e.

Extreme rogue wave generation from narrowband partially coherent waves.

In the framework of the focusing one-dimensional nonlinear Schrödinger equation, we study numerically the integrable turbulence developing from partially coherent waves (PCW), which represent superposition of uncorrelated linear waves. The long-time evolution from these initial conditions is characterized by emergence of rogue waves with heavy-tailed (non-Gaussian) statistics, and, as was established previously, the stronger deviation from Gaussianity (i.e.

Annelids of the eastern Australian abyss collected by the 2017 RV 'Investigator' voyage.

In Australia, the deep-water (bathyal and abyssal) benthic invertebrate fauna is poorly known in comparison with that of shallow (subtidal and shelf) habitats. Benthic fauna from the deep eastern Australian margin was sampled systematically for the first time during 2017 RV 'Investigator' voyage 'Sampling the Abyss'. Box core, Brenke sledge, and beam trawl samples were collected at one-degree intervals from Tasmania, 42°S, to southern Queensland, 24°S, from 900 to 4800 m depth.

A new species of Lepidotrigla from the South China Sea off Vietnam (Teleostei: Scorpaeniformes: Triglidae).

A new species of the gurnard genus Lepidotrigla is described from the South China Sea off southernmost central Vietnam. Lepidotrigra firmisquamis sp. nov.