scholarly journals Vertical zonation of the Siberian Arctic benthos: bathymetric boundaries from coastal shoals to deep-sea Central Arctic

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11640
Author(s):  
Andrey Vedenin ◽  
Sergey Galkin ◽  
Alexander N. Mironov ◽  
Andrey Gebruk

The bathymetric distribution of species of Annelida, Crustacea and Echinodermata from the region including the Kara, Laptev and East Siberian seas and the adjacent region of the deep-sea Central Arctic was analysed. We focused on vertical species ranges revealing zones of crowding of upper and lower species range limits. Using published data and in part the material obtained during the expeditions of the P.P. Shirshov Institute of Oceanology, we evaluated species vertical distribution from 0 m to the maximum depth of the Central Arctic (~4,400 m). The entire depth range was divided into smaller intervals; number of upper and lower limits of species depth ranges was counted and plotted to visualize the range limits crowding. Several zones of crowding of vertical species range limits were found for all analysed macrotaxa. The most significant zones occurred at depths of 450–800 m and 1,800–2,000 m. The first depth zone corresponds to the boundary between the sublittoral and bathyal faunas. The last one marks the boundary between the bathyal and abyssal faunas. Depths of these boundaries differ from those reported from other Ocean regions; possible explanations of these differences are discussed.

2010 ◽  
Vol 68 (2) ◽  
pp. 281-289 ◽  
Author(s):  
Imants G. Priede ◽  
Jasmin A. Godbold ◽  
Tomasz Niedzielski ◽  
Martin A. Collins ◽  
David M. Bailey ◽  
...  

Abstract Priede, I. G., Godbold, J. A., Niedzielski, T., Collins, M. A., Bailey, D. M., Gordon, J. D. M., and Zuur, A. F. 2011. A review of the spatial extent of fishery effects and species vulnerability of the deep-sea demersal fish assemblage of the Porcupine Seabight, Northeast Atlantic Ocean (ICES Subarea VII). – ICES Journal of Marine Science, 68: 281–289. We review information from scientific trawl surveys carried out between 1977 and 2002 in the Porcupine Seabight and Abyssal Plain area of the Northeast Atlantic (240–4865 m water depth). Since the late 1980s, commercial bottom-trawl fisheries targeting mainly roundnose grenadier (Coryphaenoides rupestris), black scabbardfish (Aphanopus carbo), and orange roughy (Hoplostethus atlanticus) have been operating at depths of 500–1500 m, intersecting the depth ranges of 77 demersal fish species that would therefore be vulnerable to fishery effects. Comparisons of trawls pre-1989 and post-1997 indicate a significant decrease in total abundance of demersal fish down to 2500 m. Detailed analyses of the 15 most-abundant species showed that nine species with depth ranges within the commercial fishing depth have decreased in abundance. Other species were either not affected (Bathypterois dubius) or only affected at the shallow end of their range (Coryphaenoides guentheri). Species with a minimum depth of occurrence >1500 m (Coryphaenoides armatus and Coryphaenoides leptolepis) increased in abundance over part of their depth range. Decreases in abundance are probably caused by commercial fishing activities, an effect that is transmitted downslope by removal of fish at the shallow end of their depth range, resulting in declines at the deeper end of the depth range. The estimated fishery area is ca. 52 000 km2, but the potential impact probably extends to ca. 142 000 km2 and to many non-target species.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8628
Author(s):  
Elena Rybakova ◽  
Sergey Galkin ◽  
Andrey Gebruk ◽  
Nadezhda Sanamyan ◽  
Alexander Martynov

Video surveys were carried out during the 75th cruise of the RV Akademik M.A. Lavrentyev (June 2016) along the northern slope of the Volcanologists Massif, in the south-western Bering Sea. The seafloor was explored using the ROV Comanche 18. Seven dives were performed in the depth range from 4,278 m to 349 m. Overall, about 180 species of megafauna were recognised. Fifteen types of megafauna communities corresponding to certain depth ranges were distinguished based on the most abundant taxa. Dominance changed with depth in the following order: the holothurian Kolga kamchatica at the maximum depth (4,277–4,278 m); the holothurian Scotoplanes kurilensis at 3,610–2,790 m; the ophiuroid Ophiura bathybia at 3,030–2,910 m; benthic shrimps of the family Crangonidae at 2,910–2,290 m; the holothurian Paelopatides solea at 2,650–2,290 m; benthic jellyfish from the family Rhopalonematidae at 2,470–2,130 m; the enteropneust Torquaratoridae at 2,290–1,830 m; the holothurian Synallactes chuni and the ophiuroid of the genera Ophiura and Ophiocantha at 1,830–1,750 m. At depths 1,750–720 m most of the megafauna was associated with live or dead colonies of the sponge Farrea spp. Depths 720–390 m were dominated by the coral Heteropolypus ritteri and/or Corallimorphus pilatus. At 390–350 m depth, the shallowest depth range, the dominant taxon was the zoantharian Epizoanthus sp. Soft sediment megafauna communities dominated by torquaratorid enteropneusts to our knowledge have not been observed before in the deep-sea, the same as communities with a dominance of benthopelagic rhopalonematid jellyfish. The depths of the largest community changes, or the largest turnover of dominant species, were revealed at ∼2,790 m between the bathyal and abyssal zones and ∼1,750 m and ∼720 m within the bathyal zone.


Acarina ◽  
2021 ◽  
Vol 29 (2) ◽  
pp. 189-232
Author(s):  
Ilse Bartsch

Presently, 39 Lohmannella species are accepted as valid, but future examinations may prove some of them to be junior synonyms of others. This article lists the most important descriptive papers, as well as the former names for each of the 39 species. The characters of another five species, known by their adults, are outlined but not given a name. Based on the published data, short diagnoses as well as notes on the distribution and habitats are added. In addition, the poorly known female of Lohmannella bihamata is described and illustrated. This article provides a table of morphological characters that are meant to facilitate the identification of Lohmannella species. The genus Lohmannella is spread worldwide, inhabiting all water depths and all climatic zones; its representatives live in marine and fresh water. Although the majority of Lohmannella species have been found at sea, five species have been recovered from fresh or slightly brackish water. In the following sentences, the number of unnamed species is given in square brackets. Records of 33 [plus two] marine species are exclusively from the littoral and/or bathyal zone (0–1,000 m deep); records of three [plus three] species are from the deep sea (deeper than 1,000 m); and one record is from the littoral / deep sea depth range. Most species have been found in the temperate and polar areas: namely, 12 [plus two] have been recorded north of 23°N and 20 south of 23°S. The data from the tropics include a single shallow water (0–200 m deep) record, one unnamed species from the 400–520 m depth and one [plus two] species from the depth of more than 1,000 m. Most southern hemisphere shallow water species are morphologically distinct from the bathyal and abyssal species, as well as from the northern hemisphere species.


2020 ◽  
Vol 48 (4) ◽  
pp. 168-171
Author(s):  
E. M. Krylova ◽  
A. N. Mironov ◽  
A. V. Gebruk

The article is dedicated to the memory of L.I. Moskalev – renowned bio-oceanographer, zoologist who spent his entire scientific career at the Laboratory of Ocean Bottom Fauna. L.I. Moskalev participated in more than 30 deep-sea voyages, spent 200 hours diving in manned submersibles “Pisces” and “Mir”, published about 100 scientific papers and a popular book «Masters of the Deep» (2005). Colleagues will remember Lev Moskalev – an extraordinary and deep person and a true patriot of the Laboratory and P.P. Shirshov Institute of Oceanology


Author(s):  
G. Diez ◽  
L. Arregi ◽  
M. Basterretxea ◽  
E. Cuende ◽  
I. Oyarzabal

Abstract The changes in abundance and biodiversity of deep-sea fish fauna are described based on an annual deep-water longline survey with data collected during the period 2015–2019 in the Basque Country continental Slope (ICES Division 8c). The sampling scheme included hauls in four 400 m strata, from 650–2250 m deep. The DST sensors installed in the main line have allowed us to set an accurate soak time for each haul, and they were used to calculate fishing effort and CPUE by haul. The catchability of the fishing gear indicated that 15% of the total hooks deployed in the five-year period were able to fish, and that the bottom longline was very effective in fishing a wide number of different species in all depth ranges. The fishing gear caught 14 different species of sharks (13 deepwater and one pelagic), two chimaeras and nine teleosts. The abundance and biomass registered on the hooks attached to the bottom were between three and four times higher than in the floating sections, and the highest CPUE and biomass were recorded between 1051–1450 m, from 2015 to 2017, and in the 1451–1850 m strata, but they do not show any clear trend throughout the five years of the series.


2018 ◽  
Vol 8 (1) ◽  
Author(s):  
S.S.N. Gamage ◽  
R.M.T.S. Ratnayake ◽  
A.M.A.D.M. Senadhira ◽  
D.A. Weerasinghe ◽  
V.A. Waduge

Naturally-occurring radionuclides deposited beneath the earth, which are referred to as "NORM" and other toxicnon-radioactive elements transported to the earth surface with the oil and gas production. Hence, knowledge of the prevailing background levels of these elements in the subsurface reservoir formations is valuable to all stakeholders, most notably to regulatory authorities of the country. The drill cuttings obtained within depth range 3025m to 3095m of reservoir sand section in the deep water exploratory well (CLPL- Dorado 91 H/1z) drilled in the Mannar Basin offshore Sri Lanka were subjected to high-resolution Gamma-ray spectrometry and X-ray fluorescence (XRF) spectrometry.As test results revealed activity concentration of 40K varies from 0.338 Bq/g to 0.514 Bq/g, 210Pb from 0.007 Bq/g to 0.015 Bq/g, 226Ra from 0.012 Bq/g to 0.0145 Bq/g while 232Th levels are between 0.030 Bq/g to 0.040 Bq/g. According to the XRF testing levels of significantly hazardous non-radioactive elements are considerably lower, except for the level of the Barium. The Pb level varies between the 48 ppm to 22 ppm. The Thorium level varies between 9.6 ppm to 10.1 ppm. Manganese has a range of 5,173ppm to 653ppm.The barium levels are between 118,666 ppm to 24,400 ppm. NORM concentration of the tested section were on the lower side when results matched with the IAEA published data on NORM concentration in oil, gas and there byproducts and therefore there will be low level of NORM contaminations when the Dorado gas discovery proceeds to the production stage. Further there is no harmful public exposure from NORM by disposing these drill cuttings to environment or storing at any site location. But the disposal of the drilling mud and handling of the drilling mud should be conducted with cautious since extremely high Ba levels can potentially cause health problems.Keywords: NORM, drill-cuttings, oil, gas, Sri Lanka, XRF


<em>Abstract.</em>—Extensive trawling efforts off Taiwan, supplemented by collections from trawlers’ harvest at several local fishing harbors, have raised the total number of Taiwan’s grenadier fishes to 71 species in 18 genera and 3 families. Despite a relatively limited coastline (500 nautical miles), the species diversity in Taiwan is very high. The largest genus <em>Coelorinchus </em>(formerly known as <em>Caelorinchus</em>) is represented by 21 species, followed by <em>Ventrifossa </em>with 8, and <em>Nezumia </em>with 6. All other genera had five or fewer representatives. Five species were described based on specimens from Taiwan, and two of them, <em>Coelorinchus leptorhinus </em>and <em>C. sheni, </em>have not been reported elsewhere. A total of 33 species and 10 genera are newly recorded from Taiwan; these were collected only within the past two years. Because the maximum depth trawled only reached about 2,000 m in this study, it should be expected that more deeper-water grenadiers will be found in the future. Our depth-distribution data-set of collected specimens and depth ranges from 55 stations were insufficient to effectively separate the species into groups using multivariate statistical analysis. However, the factors influencing grenadier species composition in this study still can be recognized as per the following sequence: water depth, geographical region, and type of net. The vertical distribution of grenadiers in Taiwan appears to have a separation at 600 m and 1000 m. An annotated species checklist with ASIZP cataloged specimens documenting Taiwan distributions, and detailed collecting information, including body size, location, and depth range are provided.


Paleobiology ◽  
1984 ◽  
Vol 10 (4) ◽  
pp. 469-486 ◽  
Author(s):  
W. Bruce Saunders

Bottom site remote camera photosequences at depths of 73–538 m on forereef slopes in Palau show that Nautilus belauensis is a highly mobile, chemosensitive, epibenthic scavenger and opportunistic predator. The overall depth range of this species is ca. 70–500 m, but photosequences indicate a preferred range of 150–300 m. Nautilus is active both nocturnally and diurnally, locating bait sites within 1–2 h. Associated macrofauna includes caridean shrimps, crabs, and eels; teleosts are rare below 100 m, but sharks are recorded in most photosequences below 250 m. Summarily, Nautilus exhibits a combination of characters that typify deep-sea strategy, including reproductive tactics, growth rate, and population dynamics. This and other evidence suggest that fossil Nautilidae may have been deep-water forms, in contrast to the typically shallower water ammonoids, and that Nautilus is a normal component of the deep forereef rather than a late Cretaceous refugee from shallow water.


2019 ◽  
Vol 43 (2) ◽  
pp. 396-408 ◽  
Author(s):  
Philip W. Stevens ◽  
Jynessa Dutka-Gianelli ◽  
Eric J. Nagid ◽  
Alexis A. Trotter ◽  
Kevin G. Johnson ◽  
...  

2011 ◽  
Vol 92 (5) ◽  
pp. 1043-1055 ◽  
Author(s):  
Katerina Sevastou ◽  
Paulo Henrique Costa Corgosinho ◽  
Pedro Martínez Arbizu

A new species of the genus Dahmsopottekina is described from the Mediterranean Sea. Dahmsopottekina guilvardi sp. nov. was collected from abyssal habitats at a depth range of 2340–2850 m. Like its congeners, the new species has a vermiform habitus, a highly transformed P1 in both sexes and a plough-like rostrum in the female. Dahmsopottekina guilvardi sp. nov. can be distinguished from its congeneric species by the combination of a fused basis and endopodite in P1 of both sexes and the absence of an endopodite in P2–P4 of the female. Dahmsopottekina guilvardi sp. nov. is the second record of a harpacticoid species after its congener D. peruana in which the basis and endopodite of a leg other than the P5, namely the P1, are fused. Furthermore, the new species is the only one among Dahmsopottekina species with a 1-segmented P1 exopodite in the male. Similar to its congeners, D. guilvardi sp. nov. is strongly sexually dimorphic. This is evident through the morphology of most of the cephalic appendages and the reduction of P2–P6 in the female. The results of the present study support the observation that Dahmsopottekina species are sparsely distributed and highly endemic. Nevertheless, our results do not agree with the statement of considerably larger females as the length variability between females is greater than between the two sexes. Despite the morphological characters of the species commensurate with a burrowing mode of life, its presence in sediment traps suggests that D. guilvardi sp. nov. is an active ‘swimmer’.


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