Hadal trenches, some of the Earth’s least explored and understood environments, have long been proposed to harbour chemosynthesis-based communities^1,2. Despite increasing attention, actual documentation of such communities has been exceptionally rare^3,4. Here we report the discovery of the deepest and the most extensive chemosynthesis-based communities known to exist on Earth during an expedition to the Kuril–Kamchatka Trench and the western Aleutian Trench using the manned submersible Fendouzhe. The communities dominated by siboglinid Polychaeta and Bivalvia span a distance of 2,500 km at depths from 5,800 m to 9,533 m. These communities are sustained by hydrogen sulfide-rich and methane-rich fluids that are transported along faults traversing deep sediment layers in trenches, where methane is produced microbially from deposited organic matter, as indicated by isotopic analysis. Given geological similarities with other hadal trenches, such chemosynthesis-based communities might be more widespread than previously anticipated. These findings challenge current models of life at extreme limits and carbon cycling in the deep ocean.

On cruise 82 voyage of the R/V Akademik M.A. Lavrentyev, comprehensive studies of ecosystems associated with hydrothermal vents and cold seeps in the Bering Sea were carried out. New data on...

Examination of material recently collected by the German-Russian deep-sea expeditions has revealed that new species occur regularly in macro- and meiobenthic samples of the North-Western (NW) Pacific. In this paper, we report three desmodorid species of the genera Desmodorella and Zalonema from the NW Pacific. They were studied and described using both scanning electron microscopy (SEM) and light microscopy. Desmodorella tenuispiculum (Allgen, 1928) was found at several locations in the Sea of Japan during the Russian-German expedition SoJaBio (Sea of Japan Biodiversity Studies) cruise of RV ''Akademik M.V. Lavrentyev'' in 2010, at water depths ranging between 515 and 1500 m. Zalonema granda sp. nov. and Z. kamchatkaensis sp. nov. are characterized by having a larger body size in comparison with other species of the genus. Zalonema kamchatkaensis sp. nov. is characterized by having a convex cephalic capsule, subcephalic setae (3–4 μm long) located in the middle and at the posterior region of the cephalic capsule, very large spiral amphidial fovea with 2.1–2.2 turns, sexual dimorphism in amphideal fovea size (larger in males, 39–45 μm, than in females, 37–43 μm). Zalonema granda sp. nov. is characterized by having a very long body (3.3–4.3 mm), curved elongate spicules (1.4–1.6 body diameter long), with blade broadening anteriorly towards the rounded capitulum, and pointed distally; weakly developed tubular gubernaculum, and absence of pre-cloacal supplements.

Three deep-sea tardigrade species were identified from the sediment samples collected during the four German–Russian joint deep-sea cruises that were conducted in the North-Western Pacific: Coronarctus sonne sp. nov., Moebjergarctus okhotensis sp. nov., and Angursa cf. bicuspis. Specimens of those species were collected at depths between 1700 and 5410 m. The new species Coronarctus sonne sp. nov. belongs to the Cor. tenellus group of species on the basis of morphological traits such as the short cephalic appendages and heteromorphic claws. The structure of the secondary clavae and two points, with an accessory point and a primary point simultaneously on the internal and external claws on legs IV, are significant characteristics distinguishing Coronarctus sonne sp. nov. from other described species. Moebjergarctus okhotensis sp. nov. is characterized by having cephalic cirri with the long smooth portion of the scapus and annulated scapus only in the basal portion, the structure of the male and female reproductive system, and differences in the sizes of some structures compared to the other described species. An analysis of the results of four deep-sea expeditions indicates a patchy distribution of tardigrades in the North-Western Pacific.