scholarly journals Hadal Mud Dragons: First Insight Into the Diversity of Kinorhyncha From the Atacama Trench

2021 ◽  
Vol 8 ◽  
Author(s):  
Katarzyna Grzelak ◽  
Daniela Zeppilli ◽  
Mauricio Shimabukuro ◽  
Martin V. Sørensen
Keyword(s):  
Deep Sea ◽  
Single Species ◽  
High Arctic ◽  
Abyssal Plain ◽  
Morphological Data ◽  
Marine Biodiversity ◽  
Single Individual ◽  
Large Reservoir ◽  
The North ◽  
Insight Into

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.

Benthic hydroids (Cnidaria, Hydrozoa) from bathyal and abyssal depths of the Northeast Atlantic held in the modern Discovery Collections

Zootaxa ◽  
2017 ◽  
Vol 4347 (1) ◽  
pp. 1 ◽  
Author(s):  
ÁLVARO L. PEÑA CANTERO ◽  
TAMMY HORTON
Keyword(s):  
Deep Sea ◽  
Single Species ◽  
Abyssal Plain ◽  
Generic Level ◽  
Northeast Atlantic ◽  
Porcupine Seabight ◽  
North East ◽  
The North ◽  
Rockall Trough ◽  
Mid Atlantic Ridge

The deep-sea benthic hydroid fauna remains poorly known, in part because of less frequent sampling than the shelf fauna, in part owing to the immense study area, and partly also because available samples have been little studied by experts. In order to correct this, deep-sea benthic hydroid material from the modern Discovery Collections has been studied. Samples come from localities in the North-East Atlantic including the Porcupine Seabight, Porcupine Abyssal Plain, Rockall Trough, Rockall Bank, and the Mid-Atlantic Ridge. Sixteen species belonging to 12 families and 16 genera were found. Leptothecata are clearly dominant, being represented by 14 species; the remaining species belong to Anthoathecata. Lafoeidae and Tiarannidae are the most diverse families with three species each; the remaining families being represented by a single species. The low species diversity is remarkable at the generic level, with each genus being represented by a single species. Hydroid occurrence is low: twelve species were found in ≤ 9% of stations; Amphinema biscayana has the highest occurrence (27% of stations). Fifteen species were recorded in the Porcupine Seabight, two in the Rockall Trough, one at Rockall Bank, one on the Porcupine Abyssal Plain, and two at the Mid-Atlantic Ridge. The known bathymetric range for a third of the species is extended; the increase is particularly noteworthy in Amphinema biscayana, Acryptolaria crassicaulis, Clytia gigantea and Schizotricha profunda. Two distinct bathymetric groups are recognized: strictly deep-sea inhabitants and eurybathic species. Most species are globally distributed, some are widely distributed in the Atlantic, and others are limited to the North Atlantic or the Northeast Atlantic. 

‘The North-west Passage, or voyage finished’: a polar play and musical entertainment

Polar Record ◽  
1982 ◽  
Vol 21 (131) ◽  
pp. 95-115 ◽  
Author(s):  
Daniel Claustre
Keyword(s):  
Full Text ◽  
High Arctic ◽  
Not Given ◽  
North West ◽  
The North ◽  
Original Manuscript ◽  
Polar Research Institute ◽  
Return Home ◽  
Board Ship ◽  
Insight Into

Among the collections of the Scott Polar Research Institute is the manuscript of the New Georgia Gazette, a newspaper completed on board ship during William Edward Parry's first expedition in search of a North-west Passage, 1819–20. The expedition stimulated much interest at home partly for its achievement in discovering half of the North-west Passage, and for its novelty as the first expedition deliberately to spend a winter in high Arctic latitudes. It is thus no great surprise that, after the expedition's return home, a printed version of the Gazette was published, for it provides a vivid insight into life on board ship during that unprecedented Arctic winter. However, at the back of the original manuscript of the newspaper is a play written during the expedition under the title, The North-west Passage, or voyage finished, which was not included in the publication. The reason for its exclusion is not given, but it cannot have been due entirely to the dissatisfaction of Parry, who was happy enough to refer to it in his narrative of the expedition (Parry, 1824, p 127), or to its lack of success, since it was most favourably reviewed at the time of its performance. Nor was the play ever entirely forgotten. In Jules Verne's novel, Les aventures du Capitaine Halteras (1861, part 2, p 426) Dr Clawbonny comments ‘Parry composa lui-meme pour les fetes de Noel une comedie tout a fait en situation; elle eut un immense succes et était intitulee Le Passage du Nord-Ouest ou la Fin du Voyag’. Paul-Emile Victor (1968, p 223) also mentions the play's existence, but it was only very recently that this full text of the play was rediscovered at the back of the original Gazette.The manuscript of the play is neatly handwritten in an unknown hand and occupies 19 pages measuring about 20×32 cm.

scholarly journals New hosts and morphological data for the Star pearlfish Carapus mourlani (Ophidiiformes: Carapidae) from collections made in the North Pacific coast of Costa Rica

2021 ◽  
Vol 69 (Suppl.2) ◽  
pp. S219-S233
Author(s):  
José-Leonardo Chacón-Monge ◽  
Arturo Angulo ◽  
Jorge Cortés
Keyword(s):  
Costa Rica ◽  
North Pacific ◽  
Pacific Coast ◽  
Feeding Habits ◽  
Single Species ◽  
Morphological Data ◽  
Sea Stars ◽  
The North ◽  
The Family ◽  
The North Pacific

Introduction: The family Carapidae includes about 40 species of marine fishes distributed in coastal habitats worldwide. The family includes some free-living species, however, most of them are found as commensal inquilines or parasites of marine invertebrates, including several echinoderm species. In the Eastern Tropical Pacific, the biology and host use of the representatives of the Carapidae is relatively poorly known. Objective: The present study reports the occurrence of the Star pearlfish Carapus mourlani within three previously unknown hosts in the region: the sea stars Nidorellia armata, Phataria unifascialis, and the sea cucumber Stichopus horrens. Some ecological implications and considerations regarding such symbiotic relationships are raised and discussed. Additional morphometric and meristic data for the fish and the echinoderms are also provided and discussed. Methods: Echinoderms were collected, from 25 localities along the North Pacific coast of Costa Rica, and were carefully examined searching for commensal/parasitic fishes. Echinoderms and fishes were identified and characterized in accordance with the specialized literature. Results: A total of 497 echinoderms, including about 60 species, were collected and examined. Commensal/parasitic fish (a single species represented by 13 specimens) were found in three echinoderm specimens/species. Conclusions: The list of echinoderm hosts for this carapid fish, through its whole distribution range, rises to 12 species (six sea stars and six sea cucumbers) and that could be a consequence of its wide geographic distribution, its generalist feeding habits and opportunistic commensal behavior.

scholarly journals Biogeography of acoustic biodiversity of NW Mediterranean coralligenous reefs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lucia Di Iorio ◽  
Manon Audax ◽  
Julie Deter ◽  
Florian Holon ◽  
Julie Lossent ◽  
...  
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Western Mediterranean ◽  
Ecosystem Functions ◽  
Marine Biodiversity ◽  
Predator Species ◽  
The North ◽  
Mediterranean Habitats ◽  
Geographical Regions ◽  
Nw Mediterranean

AbstractMonitoring the biodiversity of key habitats and understanding the drivers across spatial scales is essential for preserving ecosystem functions and associated services. Coralligenous reefs are threatened marine biodiversity hotspots that are challenging to monitor. As fish sounds reflect biodiversity in other habitats, we unveiled the biogeography of coralligenous reef sounds across the north-western Mediterranean using data from 27 sites covering 2000 km and 3 regions over a 3-year period. We assessed how acoustic biodiversity is related to habitat parameters and environmental status. We identified 28 putative fish sound types, which is up to four times as many as recorded in other Mediterranean habitats. 40% of these sounds are not found in other coastal habitats, thus strongly related to coralligenous reefs. Acoustic diversity differed between geographical regions. Ubiquitous sound types were identified, including sounds from top-predator species and others that were more specifically related to the presence of ecosystem engineers (red coral, gorgonians), which are key players in maintaining habitat function. The main determinants of acoustic community composition were depth and percentage coverage of coralligenous outcrops, suggesting that fish-related acoustic communities exhibit bathymetric stratification and are related to benthic reef assemblages. Multivariate analysis also revealed that acoustic communities can reflect different environmental states. This study presents the first large-scale map of acoustic fish biodiversity providing insights into the ichthyofauna that is otherwise difficult to assess because of reduced diving times. It also highlights the potential of passive acoustics in providing new aspects of the correlates of biogeographical patterns of this emblematic habitat relevant for monitoring and conservation.

Ultrastructural characteristics of spermatogenesis in three species of deep-sea hydrothermal vent mytilids

1997 ◽  
Vol 75 (2) ◽  
pp. 308-316 ◽  
Author(s):  
Marcel Le Pennec ◽  
Peter G. Beninger
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
The North ◽  
Male Gametes ◽  
Bathymodiolus Thermophilus ◽  
Nutritional Biology ◽  
Protandric Hermaphroditism ◽  
Mid Atlantic Ridge ◽  
Ultrastructural Characteristics ◽  
Species Specific

To enhance our understanding of the reproductive biology of deep-sea hydrothermal vent mytilids, the histology of the male gonad and the ultrastructure of its gametes were studied in Bathymodiolus thermophilus, B. puteoserpentis, and B. elongatus. Specimens of B. thermophilus were collected at the 13°N site on the East Pacific ridge, while B. puteoserpentis were sampled from the Snake Pit site of the mid-Atlantic ridge and B. elongatus were obtained from the North Fiji Basin. Gonad histology conformed to the typical bivalve profile; the differences in the proportions of acinal and interacinal tissue, as well as differences in acinal fullness in B. puteoserpentis, indicate that gametogenesis is discontinuous in these deep-sea mytilids. Evidence of protandric hermaphroditism was observed in B. elongatus, which exhibited acini containing both maturing and residual male gametes and immature oocytes. The ultrastructural characteristics of the male gametes conform to those described for littoral bivalve species, and the spermatozoon is of the primitive type. No species-specific differences in spermatozoon ultrastructure were discerned. No evidence of bacterial inclusions was found in either the gametes or the associated gonad cells in any of the species examined. The male gametes are thus probably not vectors for the endosymbiotic bacteria that characterize the nutritional biology of the adults in this genus.

scholarly journals Characteristics of Arctic tides at CANDAC-PEARL (80° N, 86° W) and Svalbard (78° N, 16° E) for 2006–2009: radar observations and comparisons with the model CMAM-DAS

2011 ◽  
Vol 29 (10) ◽  
pp. 1939-1954 ◽  
Author(s):  
A. H. Manson ◽  
C. E. Meek ◽  
X. Xu ◽  
T. Aso ◽  
J. R. Drummond ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Radar Data ◽  
High Arctic ◽  
Wind Component ◽  
Meteor Radar ◽  
The North ◽  
Wave Numbers ◽  
Central Canada ◽  
June July ◽  
Abstract Operation

Abstract. Operation of a Meteor Radar (MWR) at Eureka, Ellesmere Island (80° N, 86° W) began in February 2006: this is the location of the Polar Environmental and Atmospheric Research Laboratory (PEARL), operated by the "Canadian Network for the Detection of Atmospheric Change" (CANDAC). The first 36 months of tidal wind data (82–97 km) are here combined with contemporaneous tides from the Meteor Radar (MWR) at Adventdalen, Svalbard (78° N, 16° E), to provide the first significant evidence for interannual variability (IAV) of the High Arctic's diurnal and semidiurnal migrating (MT) and non-migrating tides (NMT). The three-year monthly means for both diurnal (DT) and semi-diurnal (SDT) winds demonstrate significantly different amplitudes and phases at Eureka and Svalbard. Typically the summer-maximizing DT is much larger (~24 m s−1 at 97 km) at Eureka, while the Svalbard tide (5–24 m s−1 at 97 km)) is almost linear (north-south) rather than circular. Interannual variations are smallest in the summer and autumn months. The High Arctic SDT has maxima centred on August/September, followed in size by the winter features; and is much larger at Svalbard (24 m s−1 at 97 km, versus 14–18 m s−1 in central Canada). Depending on the location, the IAV are largest in spring/winter (Eureka) and summer/autumn (Svalbard). Fitting of wave-numbers for the migrating and non-migrating tides (MT, NMT) determines dominant tides for each month and height. Existence of NMT is consistent with nonlinear interactions between migrating tides and (quasi) stationary planetary wave (SPW) S=1 (SPW1). For the diurnal oscillation, NMT s=0 for the east-west (EW) wind component dominates (largest tide) in the late autumn and winter (November–February); and s=+2 is frequently seen in the north-south (NS) wind component for the same months. The semi-diurnal oscillation's NMT s=+1 dominates from March to June/July. There are patches of s=+3 and +1, in the late fall-winter. These wave numbers are also consistent with SPW1-MT interactions. Comparisons for 2007 of the observed DT and SDT at 78–80° N, with those within the Canadian Middle Atmosphere Model Data Assimilation System CMAM-DAS, are a major feature of this paper. The diurnal tides for the two locations have important similarities as observed and modeled, with seasonal maxima in the mesosphere from April to October, and similar phases with long/evanescent wavelengths. However, differences are also significant: observed Eureka amplitudes are generally larger than the model; and at Svalbard the modeled tide is classically circular, rather than anomalous. For the semi-diurnal tide, the amplitudes and phases differ markedly between Eureka and Svalbard for both MWR-radar data and CMAM-DAS data. The seasonal variations from observed and modeled archives also differ at each location. Tidal NMT-amplitudes and wave-numbers for the model differ substantially from observations.

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

1972 ◽  
Vol 28 (4) ◽  
pp. 153-160 ◽  
Author(s):  
J. J. Morley ◽  
K. W. Potter ◽  
Y. Iwabuchi ◽  
D. J. Elvers
Keyword(s):  
Deep Sea ◽  
Abyssal Plain

scholarly journals Relationship between pollen morphology and chromosome numbers in Brazilian species of Lippia L. (Verbenaceae)

2013 ◽  
Vol 85 (1) ◽  
pp. 147-157 ◽  
Author(s):  
Saulo M. Sousa ◽  
Patrícia M.O. Pierre ◽  
Giovana A. Torres ◽  
Lisete C. Davide ◽  
Lyderson F. Viccini
Keyword(s):  
Chromosome Numbers ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Positive Association ◽  
Single Species ◽  
Morphological Data ◽  
Prolate Spheroidal ◽  
Oblate Spheroidal ◽  
Exine Ornamentation ◽  
Different Types

The pollen morphology and exine structure of 17 species of Lippia L. were investigated in this work using light and scanning electron microscopy. Among the species studied, 14 showed tricolporate pollen grains, two had tri- and tetracolporate pollen grains and a single species exhibited, only tetracolporate pollen. The amb ranged from triangular to square, and the shape varied from oblate-spheroidal to prolate-spheroidal. Three different types of exine ornamentation were observed: psilate, scabrate and perforate. In addition to morphological data, we found positive association between the chromosome numbers and size of pollen grains, and also between the length and width of the colpi. The results indicate that the characteristics of pollen grains in Lippia may be used as an additional taxonomic character of the genus.

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