Deep-sea Research Part I-oceanographic Research Papers 

About: Deep-sea Research Part I-oceanographic Research Papers is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Geology & Biology. It has an ISSN identifier of 0967-0637. Over the lifetime, 209 publications have been published receiving 362 citations. The journal is also known as: Oceanographic research papers.

Blake Ridge methane seeps: characterization of a soft-sediment, chemosynthetically based ecosystem

Abstract: Observations from the first submersible reconnaissance of the Blake Ridge Diapir provide the geological and ecological contexts for chemosynthetic communities established in close association with methane seeps. The seeps mark the loci of focused venting of methane from the gas hydrate reservoir, and, in one location (Hole 996D of the Ocean Drilling Program), methane emitted at the seafloor was observed forming gas hydrate on the underside of a carbonate overhang. Megafaunal elements of a chemosynthetically based community mapped onto dive tracks provide a preliminary overview of faunal distributions and habitat heterogeneity. Dense mussel beds were prominent and covered 20 � 20 m areas. The nearly non-overlapping distributions of mussels and clams indicate that there may be local (meter-scale) variations in fluid flux and chemistry within the seep site. Preliminary evidence suggests that the mussels are host to two symbiont types (sulfide-oxidizing thiotrophs and methanotrophs), while the clams derive their nutrition only from thiotrophic bacteria. Invertebrate biomass is dominated by mussels (Bathymodiolus heckerae) that reach lengths of up to 364 mm and, to a lesser extent, by small (22 mm length) vesicomyid clams (Vesicomya cf. venusta). Taking into account biomass distributions among taxa, symbiont characteristics of the bivalves, and stable-isotope analyses, the relative importance of methanotrophic vs thiotrophic bacteria in the overall nutrition of the invertebrate

A preliminary study of macrofaunal communities and their carbon and nitrogen stable isotopes in the Haima cold seeps, South China Sea

Abstract: The macrofaunal community in the Haima cold seeps of the South China Sea was investigated, and trophic relationships were evaluated using carbon and nitrogen stable isotope signatures (δ13C and δ15N). A total of 30 macrofaunal species were identified in this study, most of which were collected from the Gigantidas haimaensis mussel beds. Only four macrofaunal species were collected from the Calyptogena marissinica clam beds, where the environment may not be suitable for the survival of most macrofauna. The bush of slim tubeworms (Sclerolinum sp.) might be an important nursery ground for mussels. G. haimaensis was the predominant species, and its average δ13C and δ15N values were −52.7‰ and 0.6‰, respectively. Compared with the stable isotope signatures of particulate organic matter (POM), it suggested that the food source of macrofauna in the Haima cold seeps was mainly originated from chemosynthetic autotrophs. In the mussel bed, most of the macrofauna had a large δ13C isotopic distance compared with G. haimaensis, suggesting that G. haimaensis was not a direct food source for most cold-seep macrofauna in the mussel bed. The variation in stable isotope signatures of macrofauna might be attributed to different proportions of methanotrophic and thiotrophic endosymbionts. Neolithodes brodiei and Bathynomus jamesi showed the highest δ13C and δ15N values. However, the large isotopic distance indicated that N. brodiei and B. jamesi might just occasionally visit the cold-seep ecosystem and their food sources were mainly from the upper ecosystem relying on photosynthesis. Overall, our results suggested that there was no significant predator-prey relationship among these macrofaunal species in the Haima cold seeps. This study provided important baseline data of stable isotope signatures for further studies to elucidate the trophic interaction among seep organisms.

Global biogeography of the lower bathyal (700–3000 m) as determined from the distributions of cnidarian anthozoans

Abstract: The Lower Bathyal (approximately 700–800 to 3000–3500 m depth) of the deep sea, until recently, had only been explored in areas of continental slopes. With the advent of remotely operated vehicles (ROVs), seamounts and ridges, which comprise the bulk of the seafloor at those depths, have been increasingly sampled, at least for megafaunal species. We compiled records of cnidarians obtained from the Ocean Biogeographic Information System (OBIS) along with records of octocorals identified during ROV dives in the NW Atlantic and Central Pacific among other places, and used them to test the validity of the Watling et al. (2013) lower bathyal provinces which were proposed on the basis of hydrography. In addition, all records were used to independently determine the presence of biogeographic provinces using the Infomap Bioregions network analysis approach. Both methods have their shortcomings, but the combined results suggest that most of the provinces proposed by Watling et al. (2013) were reasonably well delineated; some changes were needed, especially in the North Atlantic. Specifically, the North Atlantic province needs to be divided into eastern and western units and the boundaries of the Boreal NW Atlantic (=Northern Atlantic Boreal) should be extended southward. Several name changes for various provinces are also proposed. Apparent endemism for those provinces where sufficient records exist was at least 33%, much higher than the 10% normally used when evaluating shallow water biogeographic provinces.

Deep and cold: are Boreal and Arctic finned octopods, Stauroteuthis syrtensis and Cirroteuthis muelleri (Cephalopoda, Octopoda, Cirrata), ecological analogues?

Abstract: Stauroteuthis syrtensis and Cirroteuthis muelleri were studied based on representative material collected in Greenland, Iceland, and the Barents Sea and adjacent deep-sea areas (96 stations and 165 individuals for S. syrtensis, and 82 stations and 215 individuals for C. muelleri). The species occur on the border of the Arctic and the northern North Atlantic; S. syrtensis is a southern species and C. muelleri is a northern species, in the area from the Denmark and Davis Straits and associated underwater ridges. These species were demonstrated to be ecological analogues since they: a) occupy the same depths; b) reach the same abundance density; c) reach virtually the same biomass density when corrected for size differences; and d) their food spectra largely coincide. Temperature, not depth, is a principal factor that prevents these species from crossing the border between the Arctic and the northern North Atlantic, with mean habitat temperatures of 3.5 ± 0.06 °C for S. syrtensis and 0.3 ± 0.06 °C for C. muelleri. This study provides unprecedented density estimates for the North Atlantic and Arctic Cirrata: the highest in the world ocean in terms of biomass and second highest in terms of numerical abundance. Food spectra of the studied species consist of Calanoida (including eurybathic Paraeucheta spp. and Calanus spp., and deep-sea Bradyidius similis), Mysidacea and Isopoda (including deep-sea Eurycopinae) (Crustacea), and in C. muelleri also Cumacea, Amphipoda (Crustacea) and Polychaeta (Polynoidae). Additionally, this study: a) provides specific growth and morphometric equations; b) provides equations to estimate mantle length (ML) and body mass (BM) from beak measurements, and BM of fresh individuals (for modelling purposes or predators diet analyses) from BM of fixed individuals; c) reports maximum sizes for C. muelleri (ML 170 mm, total length 400 mm, BM 781.0 g); and d) reports findings of rarely encountered juvenile cirrates.

Megafaunal assemblages in deep-sea ecosystems of the Gulf of Cadiz, northeast Atlantic ocean

Abstract: Deep-sea ecosystems of the Iberian margin have been widely impacted over the past decades, but the limited knowledge on their biodiversity and functioning limits our ability to contribute to their conservation. So far, in the Gulf of Cadiz, research has mostly been focused on megabenthic assemblages associated to mud volcanoes. However, several other geomorphological structures have remained widely unexplored. Here, by means of a quantitative analysis of 17 video transects conducted between 220 and 980 m depth, we investigated megabenthic assemblages associated to canyons, contouritic channels, contouritic furrows and open slopes. We report the presence of 8 different assemblages, segregated as a result of the different substrates and geomorphologic features. Megabenthic assemblages on hard substrates were characterized by mono or multispecific sponge assemblages. Soft bottoms hosted crinoid beds, pennatulacean meadows and fields of the gorgonian Radicipes gracilis. These results highlight the high diversity of megabenthic assemblages in deep-sea ecosystems of the Gulf of Cadiz and suggest that most of the geomorphological features that remained so far unexplored represent vulnerable marine ecosystems deserving protection and inclusion in future management plans.