Foraminiferal distribution and sedimentary facies on the Grand Banks of Newfoundland

1969 ◽  
Vol 6 (3) ◽  
pp. 475-487 ◽  
Author(s):  
B. K. Sen Gupta ◽  
R. M. McMullen
Keyword(s):  
Sedimentary Facies ◽  
Abundant Species ◽  
Large Area ◽  
Grand Banks ◽  
The North ◽  
Gravel Size ◽  
Labrador Current ◽  
Seaward Edge ◽  
Total Ratio ◽  
North Western

The southern part of the Grand Banks can be divided into three sedimentary regions. The north western region is dominated by gravel-size material; this is probably a reworked glacial sediment and its limit may indicate the seaward edge of the Quaternary ice sheet. The other regions are both dominated by sand-size pro-glacial material reworked in post-glacial times. The southwestern region includes a large area of finer sediment, which shows the highest density of foraminiferal tests. Dominant lineations indicate the probable influence of the Labrador Current and the Gulf Stream in the distribution of sediments.On the Tail of the Bank, an inverse relationship is commonly present between the density of the benthonic tests and the grain-size of the sediment. Of the 88 species present in the benthonic assemblage, 31 occur in 30% or more of the stations and only 5 occur in more than 90% of the stations. Islandiella islandica (Nørvang) is the most abundant species. The distribution of the living/total ratio in the benthonic Foraminifera is erratic, but particular areas of significantly high or low ratios may be related to different rates of sedimentation. The distribution of the planktonic assemblage, dominated by Globigerina pachyderma (Ehrenberg), is apparently controlled mainly by the movement of the Labrador Current waters. The percentage of planktonic tests in the total foraminiferal population decreases sharply on the shallow plateau, inward from the edge of the Bank.

scholarly journals Deep-Water Cartilaginous Fishes in the Central Mediterranean Sea: Comparison between Geographic Areas with Two Low Impact Tools for Sampling

2021 ◽  
Vol 9 (7) ◽  
pp. 686
Author(s):  
Angela Carluccio ◽  
Francesca Capezzuto ◽  
Porzia Maiorano ◽  
Letizia Sion ◽  
Gianfranco D’Onghia
Keyword(s):  
Adriatic Sea ◽  
Fish Habitat ◽  
Conservation Status ◽  
Abundant Species ◽  
Cartilaginous Fish ◽  
Fish Diversity ◽  
Ionian Sea ◽  
Central Mediterranean ◽  
The North ◽  
North Western

Baited lander represents a low impact technique, an alternative to the traditional trawl sampling for collecting data on fish diversity and abundance, especially for threatened species such as Chondrichthyes living in sensitive habitats. In this study, distribution and abundance of cartilaginous fish were compared between two geographic areas, the southern Adriatic Sea and the north-western Ionian Sea, with two low impact sampling gears, an experimental bottom longline and a baited lander. Species diversity was evaluated by applying ecological indices and difference in mean abundances were tested using multivariate analysis. A total of 13 species of cartilaginous fish were collected. Significant differences in the assemblage recorded in the same area using different sampling tools were detected and no significant differences were detected among different areas explored with the same method. Using longline, the most abundant species collected in both areas was Galeus melastomus, while using lander, the most observed species were Dalatias licha in the southern Adriatic Sea and Hexanchus griseus in the north-western Ionian Sea. According to IUCN classification, of the 13 species collected, 2 are near threatened and 5 are threatened. A better governance of sensitive habitats coinciding with the essential fish habitat for these species would ensure them a better conservation status.

The Distribution and Diet of the Dominant, Slope-Dwelling Eel, Synaphobranchus Kaupi, of the Rockall Trough

1996 ◽  
Vol 76 (2) ◽  
pp. 493-503 ◽  
Author(s):  
J.D.M. Gordon ◽  
J. Mauchline
Keyword(s):  
North Atlantic ◽  
Abundant Species ◽  
Otter Trawl ◽  
Grand Banks ◽  
Middle Atlantic ◽  
The North ◽  
Epibenthic Sledge ◽  
Continental Slopes ◽  
The Usa ◽  
Eastern North Atlantic

INTRODUCTIONThe deep-sea eel, Synaphobranchus kaupi, is widely distributed on the continental slopes of the North Atlantic (Saldanha & Bauchot, 1986; Haedrich & Merrett, 1988). It was a dominant fish species in epibenthic sledge and semi-balloon otter trawl (OTSB) hauls on the West African slope (Merrett & Marshall, 1981; Merrett & Domanski, 1985). Also in the eastern North Atlantic, it was the most abundant species on the slopes of the Porcupine Sea Bight off south-west Ireland (Merrett et al., 1991; Priede et al., 1994). In the western North Atlantic, it was the dominant species on the middle and lower slopes of the Middle Atlantic States of the USA and on the upper slopes of the Grand Banks off Newfoundland (Sedberry & Musick, 1978; Houston & Haedrich, 1986).

scholarly journals Diatoms (Bacillariophyta) associated with lichens from Ulu Peninsula (James Ross Island, NE Antarctic Peninsula)

2018 ◽  
Vol 8 (2) ◽  
pp. 151-161 ◽  
Author(s):  
Barbora Chattová
Keyword(s):  
Antarctic Peninsula ◽  
Abundant Species ◽  
Weddell Sea ◽  
Diatom Flora ◽  
Fine Grained ◽  
The North ◽  
Large Island ◽  
James Ross Island ◽  
The Antarctic ◽  
North Western

Since 2000, the entire Antarctic diatom flora is being revised using a more fine-grained taxonomy based on a better analysis and interpretation of the morphological and molecular observations. Despite the increased diatom research and efforts, the diversity and ecology of diatoms of lichen inhabiting flora of James Ross Island weren’t studied yet. To reveal the actual diatom diversity, samples were collected during February and March 2018 from lichens on the Ulu Peninsula, James Ross Island, a 2,450 km2 large island, situated in the north-western part of the Weddell Sea, close to the northern tip of the Antarctic Peninsula. The analysis of 29 lichen samples revealed the presence of 56 diatom taxa belonging to 17 genera. The most abundant species were Luticola muticopsis, Hantzschia amphioxys f. muelleri, Pinnularia borealisvar.scalaris, Luticola aff. pusilla and Achnanthes muelleri. Biogeographically, the lichen-inhabiting diatom flora of the Ulu Peninsula is composed of cosmopolitan, Antarctic and endemic elements. The present study is the first focusing on the diversity of lichen-inhabiting diatom communities on James Ross Island, revealing the presence of a rather species rich diatom flora.

Were Jurassic tholeiitic lavas originally widespread in southeastern Canada?: a test of the broad terrane hypothesis

1999 ◽  
Vol 36 (9) ◽  
pp. 1509-1516 ◽  
Author(s):  
Georgia Pe-Piper ◽  
David JW Piper
Keyword(s):  
Atlantic Canada ◽  
Large Area ◽  
Grand Banks ◽  
Type Section ◽  
The North ◽  
Geochemical Variations ◽  
Competing Models ◽  
Uplift And Erosion ◽  
Newark Basin ◽  
Fundy Basin

Two competing models have been proposed for Early Jurassic magmatism on the eastern North American margin. The "broad terrane" hypothesis argues that tholeiitic lavas were extruded over a large area and later eroded. Alternatively, the lavas were extruded only in the basins in which they now outcrop. We compare the stratigraphy and geochemistry of the tholeiitic lavas and dykes from Atlantic Canada with those of the type section of the Newark basin and use this correlation to test these two models. The earliest high-Ti quartz tholeiites in the type section are represented by lavas in the Fundy basin (North Mountain Basalt), Scotian basin, and eastern Grand Banks and by the Shelburne and Ministers Island dykes. Spatial and temporal geochemical variations in the North Mountain Basalt are mirrored by the Shelburne dyke, strengthening the case that the two were geochemically related. Basalts in Grand Manan Island, on the footwall of the Grand Manan fault that bounds the Fundy basin, are geochemically similar to the lowest North Mountain Basalt flow. These observations suggest that the earliest basalt flows were originally more extensive and have become restricted by later uplift and erosion. However, younger magmas in the Newark basin are represented only by the Caraquet, Anticosti, and Avalon dykes in Atlantic Canada, and corresponding lavas were never deposited in the Fundy basin or eastern Grand Banks. Thus, Jurassic tholeiitic lava distribution lies in between the predictions of the "broad terrane" and the "restricted basin" models.

Demersal cephalopods of the Gulf of Carpentaria, Australia

1994 ◽  
Vol 45 (3) ◽  
pp. 351 ◽  
Author(s):  
M Dunning ◽  
S McKinnon ◽  
CC Lu ◽  
J Yeatman ◽  
D Cameron
Keyword(s):  
Minor Component ◽  
Abundant Species ◽  
Northern Australia ◽  
Australian Species ◽  
The North ◽  
Sepia Pharaonis ◽  
Catch Rates ◽  
A Minor ◽  
North Western ◽  
High Catch

Demersal trawl and dredge surveys of the Gulf of Carpentaria in the early summers of 1990 and 1991 provided the first comprehensive assessment of the cephalopod fauna of this shallow, tropical basin off northern Australia. Twenty-one taxa (comprising five loliginid squids, seven cuttlefishes, seven octopuses and two dumpling squids) were recorded. In addition to hosting species distributed broadly in the Indo-West Pacific (e.g. loliginid squids Sepioteuthis lessoniana, Photololigo cf. chinensis and P. cf. edulis; cuttlefishes Sepia eiliptica and Sepia pharaonis), the Gulf of Carpentaria represents the most northwesterly extent of the range of some eastern Australian species (e.g. Loliolus noctiluca and Sepia whitieyana). Squid catches were lower in the north-western gulf in 1990 and higher in shallower water during the more geographically restricted survey in 1991, whereas cuttlefish were more evenly distributed throughout the different sampling areas in both years. Broad size ranges of both sexes of the four most abundant species (P. cf. chinensis (northern form), P. cf. eduiis, S. eiliptica and S. pharaonis) are indicative of extended spawning seasons, and fully mature individuals of these species were evident throughout the gulf. Cephalopods are a minor component in reported domestic fisheries catches from the Gulf of Carpentaria, where penaeid prawns are targeted. High (though seasonal) squid catch rates were reported annually by Taiwanese trawlers targeting butterfish and squid from certain areas prior to 1979. With the observed population structure of the abundant cephalopod species and relatively high catch rates in some localities during these recent surveys, it is suggested that the cephalopod resources of the Gulf of Carpentaria could support increased commercial fisheries exploitation.

scholarly journals Population structure and reproduction of three sympatric species of hermit crabs in the north-western Mediterranean

2004 ◽  
Vol 84 (2) ◽  
pp. 371-376 ◽  
Author(s):  
E. Macpherson ◽  
N. Raventos
Keyword(s):  
Sex Ratio ◽  
Reproductive Activity ◽  
Abundant Species ◽  
Sympatric Species ◽  
Western Mediterranean ◽  
Hermit Crabs ◽  
Seasonal Abundance ◽  
Sexually Dimorphic ◽  
The North ◽  
North Western

The populations of three sympatric hermit crabs, Pagurus excavatus, Anapagurus alboranensis and Anapagurus petiti were studied in a shallow (15–25 m) sandy area in the north-western Mediterranean. Seasonal abundance, seasonal size frequency, sex ratio and reproductive periods were examined. Pagurus excavatus was the largest and most abundant species in the zone. Pagarus excavatus and Anapagarus alboranensis are sexually dimorphic in relation to size, with males reaching larger sizes than females. However, the males and females of Anapagurus petiti reach similar large sizes. Anapagurus petiti has a sex ratio that is female biased, whereas A. alboranensis and P. excavatus are 1:1. Anapagurus petiti showed a higher reproductive activity during warmer seasons, while in A. alboranensis the proportion of ovigerous females was high throughout the year, with a minimum in autumn. The activity and clutch size of P. excavatus decreased during summer.

Late Cenozoic evolution of Sackville Spur: a sediment drift on the Newfoundland continental slope

1990 ◽  
Vol 27 (6) ◽  
pp. 863-878 ◽  
Author(s):  
L. Kennard ◽  
C. Schafer ◽  
L. Carter
Keyword(s):  
Continental Slope ◽  
Large Scale ◽  
Lower Percentage ◽  
Western Boundary ◽  
Sediment Reworking ◽  
Grand Banks ◽  
The North ◽  
Sediment Drift ◽  
Labrador Current ◽  
Erosional Event

The Sackville Spur is a sediment drift feature that forms a northeastward extension of the Grand Banks continental slope between the 900 and 2500 m isobaths near latitude 48°N. At present, the Labrador Current (LC) and the Western Boundary Undercurrent (WBUC) appear to be the two major hydrodynamic forces controlling sedimentation patterns on the flanks of the spur. Near the upper part of the spur's north flank, a deep offshore component of the LC appears to be selectively winnowing silt and clay-size particles, leaving a lag deposit composed of about 43% sand-size material. The base of the north flank (≈2500 m) is in a zone in which sediments can be reworked by the fast-flowing core of the WUBC. Here surficial sediments are characterized by a relatively high percentage of fine (2–3[Formula: see text]) sand and by a lower percentage of silt compared with sediments observed near the spur crest.Reflection seismic data suggest that current-influenced deposition, associated predominantly with bottom-sediment reworking by the deeper offshore component of the LC, has been active over the uppermost part of the spur since Late Miocene to Early Pliocene time. The initiation of deep LC flow at this time is marked by a distinctive angular unconformity near the base of the spur drift deposit. Following this erosional event, deposition caused rapid progradation of the spur to the northeast. The latest phase of the spur's evolution is characterized by (i) intermittent erosion with concomitant large-scale submarine sliding; (ii) smaller scale mass-flow deposition; and (iii) a distinctive southeastward shift of its depocentre toward the Flemish Pass.

scholarly journals Linear Transect Surveys of Abundance and Density of Cetaceans in The Area Near the Dzharylgach Island in the North-Western Black Sea

2017 ◽  
Vol 51 (4) ◽  
pp. 335-342
Author(s):  
E. V. Gladilina ◽  
K. A. Vishnyakova ◽  
O. O. Neprokin ◽  
Yu. F. Ivanchikova ◽  
T. A. Derkacheva ◽  
...  
Keyword(s):  
Black Sea ◽  
Coastal Area ◽  
Bottlenose Dolphins ◽  
Habitat Preferences ◽  
Abundant Species ◽  
Cetacean Species ◽  
The North ◽  
The Common ◽  
Common Dolphins ◽  
North Western

Abstract The first assessment of cetacean density and abundance by linear transect survey was conducted in 2016 and 2017 in the shallowest coastal area of the Ukrainian sector of the north-western Black Sea, in the Dzharylgach Gulf and the northern Karkinit Gulf, total area up to 259 km2. Three cetacean species were found present in the area in summer, and the harbour porpoise was the most abundant species with the abundance of at least a few hundred animals (estimated as 175 individuals in the Dzharylgach Gulf), whereas the common dolphins (59) and bottlenose dolphins (31) were present in lesser numbers. Common and bottlenose dolphins showed the clearest patterns of habitat preferences, being restricted respectively to the Dzharylgach and the northern Karkinit Gulf; an unusual trait is the preference of the shallowest habitat by common dolphins. Recorded density of harbour porpoises in the Dzharylgach Gulf is among the highest in the whole Black Sea. Thus, the studied area may be an important summer habitat for cetaceans.

Impact of melting of the Laurentide Ice Sheet on sediments from the upper continental slope off southeastern Canada: evidence from Sm–Nd isotopesThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.

2008 ◽  
Vol 45 (11) ◽  
pp. 1243-1252 ◽  
Author(s):  
R. K. Stevenson ◽  
X. W. Meng ◽  
C. Hillaire-Marcel
Keyword(s):  
Continental Slope ◽  
North American ◽  
Ice Sheet ◽  
Isotopic Signature ◽  
Grand Banks ◽  
The North ◽  
Climate Stability ◽  
Labrador Current ◽  
Younger Dryas Event ◽  
Glacial Tills

We present new Sm–Nd isotope data for sediments from a core located on the continental slope of the St. Pierre Bank of Canada’s east coast. The Nd analyses indicate that the sediments were derived from two principal sources: the North American Shield that yields an average early Proterozoic isotopic signature and a younger Proterozoic signature attributed to Appalachian crustal sources. The Appalachian-sourced sediments predominated during the last glacial maximum (LGM) and were associated with low sedimentation rates (<30 cm/ka), with the exception of a strong North American Shield signature present in a detrital carbonate layer that corresponds to Heinrich Layer 1 (H1). The dominance of the Appalachian signature decreased subsequent to H1. The Appalachian signatures closely follow the distribution of sediments interpreted as locally derived glacial tills, while the North American Shield signatures follow the distribution of hemipelagic mud that was likely deposited by the Labrador Current. The Nd data are consistent with the persistence of the Wisconsinan Ice Sheet coverage of Newfoundland and the Grand Banks after the LGM, although the coverage began to wane prior to 12.5 ka as evidenced by the increasing influence of the Labrador Current. However, an increase in the Appalachian isotope signature at the close of the Younger Dryas event likely indicates the final melting of the ice sheet covering the Grand Banks and the Avalon Peninsula, and the initiation of the Labrador Current’s modern circulation pathway.

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