Bathymetry of three deep-sea channels in the northeast and central Tufts Abyssal Plain

Deep-sea trenches are one of the last frontiers for deep-sea exploration and represent a large reservoir of undiscovered biodiversity. This applies in particular to organisms belonging to smaller-size classes, such as meiofauna. Among different meiofauna taxa, kinorhynchs represent a large gap in our knowledge about global marine biodiversity in general, but primarily in extreme deep-sea environments. Out of the more than 300 known mud dragon species, only a single species has ever been described from hadal depths (> 6000 m), i.e., Echinoderes ultraabyssalis from the Kuril-Kamchatka Trench. The results presented in this paper are based on material collected during a research expedition in 2018 investigating the Atacama Trench environment. We provide a first overview and comparison of the diversity and abundance of mud dragons in the Atacama Trench, the adjacent abyssal plain and continental slope off Chile. The study revealed six species of Echinoderes. Of these, Echinoderes mamaqucha sp. nov. is described as a new species and morphological data of three undescribed species are given. Because of the low number of available specimens, we provide only a brief description of these three species and comparison with their morphologically closest congeners, but formal descriptions are not given. Moreover, Echinoderes juliae and Echinoderes pterus were also recovered. Echinoderes juliae was described from the abyssal plain off Oregon and along the continental rise off California, at 2702 to 3679 m depth. Echinoderes pterus is known from the high Arctic, the North Atlantic, and the Mediterranean Sea, and has also been reported to show a wide bathymetric distribution, from 675 to 4403 m. Interestingly, E. mamaqucha sp. nov. dominated at the trench stations and it reached its highest abundance at the deepest station, at 8085 m water depth. The only other single individual that was found in the Atacama Trench was Echinoderes sp.1. The remaining four species were all found at the abyssal and slope stations. The obtained results seem to confirm previous hypotheses about geographic isolation of deep-sea trenches and relatively low connectivity with other habitats, reflected by limited diversity of sediment dwelling fauna, particularly in the deepest parts of trenches.

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Linkages between the occurrence of persistent organic pollutants and biogeochemical characteristics of deep-sea trenches

10.5194/egusphere-egu2020-478 ◽

2020 ◽

Author(s):

Gisela Horlitz ◽

Stefano Bonaglia ◽

Igor Eulaers ◽

Ronnie N. Glud ◽

Anna Sobek

Keyword(s):

Organic Matter ◽

Organic Pollutants ◽

Persistent Organic Pollutants ◽

Deep Sea ◽

Sediment Cores ◽

Abyssal Plain ◽

Organic Carbon Content ◽

Focusing Effect ◽

Degradation Rates ◽

Wide Range

<p>The biogeochemistry of deep-sea trenches is strongly influenced by their V-shape topography and tectonic position in the ocean, leading to a focusing effect of sediment and organic matter into the trench centre. Recent findings showed elevated mineralization rates in trench sediments, suggesting both high carbon turnover and organic matter degradation rates. As persistent organic pollutants (POPs) favourably partition to organic matter, deep-sea trenches act as a sink for these substances. Composition, source and age of the organic matter have been shown to have a significant influence on contaminant dynamics in sediment from more shallow regions. Also, the trophic status of marine systems plays a significant role in transport of POPs from air to water and to sediment. However, knowledge about organic pollutants in deep-sea environments is scarce. In the present study, sediment samples from two deep-sea trenches with different trophic states and deposition regimes are analysed for POPs with a wide range of physicochemical properties. Concentrations will be compared between the semi-eutrophic Atacama and the oligotrophic Kermadec Trench. Sampling of sediment cores was performed at the slope, abyssal plain and trench at Atacama (depth between 2,500 and 8,000m) and at the abyssal plain and trench at Kermadec (depth of 6,000 and 9,600m). The total organic carbon content largely varied between 0.3 and 2.1% at different sites at the Atacama Trench, while values were more homogeneous at the Kermadec Trench (around 0.3%). Preliminary results from the Atacama samples demonstrate concentrations of PCBs at the pg g<sup>-1</sup> dw level, and indicate highest concentrations to occur at the highest depth in the trench. Low sedimentation- and high mineralization rates in the trench centre, as well as the funnel-effect from the topology may explain these differences.</p>

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Organic matter in deep-sea sediments from the Porcupine Abyssal Plain in the north-east Atlantic Ocean. I—Lipids

Deep Sea Research Part I Oceanographic Research Papers ◽

10.1016/0967-0637(94)90077-9 ◽

1994 ◽

Vol 41 (5-6) ◽

pp. 787-819 ◽

Cited By ~ 76

Author(s):

Vera Santos ◽

David S.M. Billett ◽

Anthony L. Rice ◽

George A. Wolff

Keyword(s):

Organic Matter ◽

Atlantic Ocean ◽

Deep Sea ◽

Abyssal Plain ◽

East Atlantic ◽

North East ◽

The North ◽

Deep Sea Sediments

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Aleutian Deep-sea Channel on the Aleutian Abyssal Plain

Nature ◽

10.1038/2281081a0 ◽

1970 ◽

Vol 228 (5276) ◽

pp. 1081-1082 ◽

Cited By ~ 4

Author(s):

FREDERIC P. NAUGLER

Keyword(s):

Deep Sea ◽

Abyssal Plain

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Deep-sea scavenging amphipod assemblages from the submarine canyons of the Iberian Peninsula

Biogeosciences Discussions ◽

10.5194/bgd-9-7831-2012 ◽

2012 ◽

Vol 9 (6) ◽

pp. 7831-7851 ◽

Cited By ~ 1

Author(s):

G. A. Duffy ◽

T. Horton ◽

D. S. M. Billett

Keyword(s):

Deep Sea ◽

Free Fall ◽

Submarine Canyon ◽

Vital Role ◽

Abyssal Plain ◽

Submarine Canyons ◽

Faunal Assemblages ◽

Baited Traps ◽

Different Depths ◽

Food Falls

Abstract. Submarine canyons have often been identified as hotspots of secondary production with the potential to house distinct faunal assemblages and idiosyncratic ecosystems. Within these deep-sea habitats, assemblages of scavenging fauna play a vital role in reintroducing organic matter from large food falls into the wider deep-sea food chain. Free-fall baited traps were set at different depths within three submarine canyons on the Iberian Margin. Amphipods from the traps were identified to species level and counted. Scavenging amphipod assemblages were compared at different depths within each canyon, between individual canyon systems, and between the abyssal plain and submarine canyon sites. Samples from canyons were found to contain common abyssal plain species but in greater than expected abundances. Community composition differed significantly between the submarine canyons and abyssal plains. It is proposed that this is a result of the high organic carbon input into canyon systems owing to their interception of sediment from the continental shelf and input from associated estuarine systems.

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A new and exceptional species of Bradya Boeck, 1873 (Copepoda: Harpacticoida:Ectinosomatidae) from the abyssal plain of the Angola Basin and the variabilityof deep-sea Harpacticoida

Zootaxa ◽

10.11646/zootaxa.1866.1.15 ◽

2008 ◽

Vol 1866 (1) ◽

pp. 303 ◽

Cited By ~ 5

Author(s):

SYBILLE SEIFRIED ◽

PEDRO MARTÍNEZ ARBIZU

Keyword(s):

Deep Sea ◽

Morphological Variability ◽

The Body ◽

Abyssal Plain ◽

Shallow Waters ◽

Northeast Atlantic ◽

Outer Seta ◽

Cephalothorax Length

Bradya kurtschminkei sp. nov. is described from deep-sea samples collected from the Angola Basin (Southeast Atlantic) during the DIVA 1 campaign in 2000, the Guinea and Cape Basins (Southeast Atlantic) during the DIVA 2 campaign in 2005, and the Porcupine Abyssal Plain (Northeast Atlantic) during the RRS ‘‘Challenger’’ cruise 111 in 1994. B. kurtschminkei sp. nov. is exceptional because of many characters, hitherto unknown from other Bradya species. B. kurtschminkei sp. nov. can be distinguished from its congeners by its unique habitus as the body is slightly flattened dorso-ventrally and the female cephalothorax is almost as long as the free pedigerous somites and the urosome together. The rostrum’s length is a third of the cephalothorax length and it tapers to a point. The antennule is 5-segmented, the basis of maxillule is fused with exopod and endopod, and the endopod has only four setae. The endopod of maxilla has only one large claw, the exopod of the P5 is short, its distal end reaches to the distal end of the baseoendopod, and the outer seta of the baseoendopod has a double tip. The armature formula of P1–P4 is exceptional as there are in total seven setae less on the endopods than in all other species of Bradya. Like many other deep-sea Harpacticoida, B. kurtschminkei sp. nov. shows compared with shallow waters species a remarkable, as yet unknown morphological variability.

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