Biological and ecological aspects of the deep‐water red crab populations inhabiting isolated seamounts to the west of the Azores (Mid‐Atlantic Ridge)

2019 ◽  
Vol 28 (6) ◽  
pp. 723-734 ◽  
Author(s):  
Régis Santos ◽  
Mário Pinho ◽  
Octávio Melo ◽  
João Gonçalves ◽  
Ana Leocádio ◽  
...  
Keyword(s):  
Deep Water ◽  
The West ◽  
Ecological Aspects ◽  
Mid Atlantic Ridge

scholarly journals 14C in the Deep Water of the East Atlantic

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 391-396 ◽  
Author(s):  
Reiner Schlitzer
Keyword(s):  
Deep Water ◽  
Large Scale ◽  
Bottom Water ◽  
Source Parameters ◽  
Potential Temperature ◽  
Source Terms ◽  
East Atlantic ◽  
The West ◽  
Model Calculations ◽  
Inflowing Water

The renewal of east Atlantic deep water and its large-scale circulation and mixing have been studied in observed distributions of temperature, silicate, ΣCO2, and 14C. 14C variations in northeast Atlantic deep water below 3500m depth are small. Δ14C values range from − 100‰ to −125‰. 14C bottom water concentrations decrease from Δ14C =−117‰ in the Sierra Leone Basin to Δ14C = − 123‰ in the Iberian Basin and are consistent with a mean northward bottom water flow. The characteristic of the water that flows from the west Atlantic through the Romanche Trench into the east Atlantic was determined by inspection of θ/Δ14C and θ/SiO2 diagrams. A mean potential temperature of θ = 1.50 ± .05°C was found for the inflowing water. A multi-box model including circulation, mixing, and chemical source terms in the deep water has been formulated. Linear programing and least-squares techniques have been used to obtain the transport and source parameters of the model from the observed tracer fields. Model calculations reveal an inflow through the Romanche Trench from the west Atlantic, which predominates over any other inflow, of (5 ± 2) Sv (potential temperature 1.50°C), a convective turnover of (150 ± 50) years and a vertical apparent diffusivity of (4 ± 1) cm2/s. Chemical source terms are in the expected ranges.

Deep-Water Contourite Drifts in the West of North-China Platform

2013 ◽  
Vol 318 ◽  
pp. 447-452
Author(s):  
Shun She Luo ◽  
Zhen Zhong Gao ◽  
You Bin He ◽  
Qi Qi Lv ◽  
Ying Meng
Keyword(s):  
Deep Water ◽  
North China ◽  
The West ◽  
North China Platform ◽  
Middle Ordovician ◽  
Contourite Drifts

The middle Ordovician of Pingliang area on the west margin of North-China platform is represented by a succession of deep-water sediments in which contourites are well-developed. Contour current deposits are well-developed. The contourites can be classified into:calcarenitic contourite, calcisiltitic contourite and calcilutitic contourite. Three typical contourite successions are recognized: complete contourite succession, incomplete contourite succession and contourite successions consisting only of calcarenitic contourites. According to the palaeocorrent and the palaeogeographic format analyse,carbonate contourite drift in the study area is unfolded crossing northwest-southeast, forwarding from southeast to northwest along the slope, and compared with other contourite drifts, it has some characteristics of coarser-grained sediment, thicker individual layers, and highly developed calcarenitic contourites and so on.

Spectrum Analysis of Deep Water Ambient Noise in the West Pacific

2021 ◽  
Author(s):  
Jiahua Zhu ◽  
Wei Guo ◽  
Bingbing Zhang ◽  
Yanxin Ma ◽  
Yangyang Chen ◽  
...  
Keyword(s):  
Deep Water ◽  
Spectrum Analysis ◽  
Ambient Noise ◽  
The West ◽  
West Pacific

Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries

2008 ◽  
Keyword(s):  
Deep Water ◽  
Stock Assessment ◽  
Data Availability ◽  
Biological Knowledge ◽  
Human Consumption ◽  
British Isles ◽  
The North ◽  
Mid Atlantic Ridge ◽  
Pros And Cons ◽  
A Minor

<em>Abstract</em>.—The biology and fisheries of macrourid species in the NE Atlantic are reviewed. Of about 30 species that occur within that area, the roundnose grenadier <em>Coryphaenoides rupestris </em>is one of the main target species of deep-water fisheries. Roughhead grenadier <em>Macrourus berglax </em>is a minor bycatch of other deep-water fisheries and an occasional target of some small fisheries. Other macrourid species are not commercially exploited because they are too small and/or in too deep waters, but some are also taken as accidental bycatch. There are three main fisheries for roundnose grenadier: north and west of the British Isles, Skagerrak, and Mid-Atlantic Ridge. The Skagerrak fishery is mainly for fish meal while the others are for human consumption. Due to data availability, a range of assessment methods has been trialled primarily for stocks to the north and west of the British Isles. Although uncertain, these assessments provide evidence that the stock has been severely depleted. Fisheries were largely unregulated until the early 2000s, but following repeated International Council for the Exploration of the Sea (ICES) advice, total allowable catches were introduced in 2003 together with effort and capacity regulations. Roundnose grenadier is the most studied species. It lives more than 50 years, compared to 30 years or more for roughhead grenadier. The limited knowledge of other species suggests a contrasting picture of maximum age ranging from 10 to 40 years. Taking into account the limited biological knowledge for these species, the pros and cons of the current management regime are discussed.

Damnaster tasmani, a new genus and species of Asteoidea (Echinodermata) from New Zealand

1994 ◽  
Vol 8 (6) ◽  
pp. 1397 ◽  
Author(s):  
HES Clark ◽  
DG McKnight
Keyword(s):  
New Zealand ◽  
Deep Water ◽  
New Genus ◽  
New Genus And Species ◽  
The West

Damnaster tasmani, gen. et sp. nov., belonging in the deep-water asteroid family Porcellanasteridae, is described from five stations (nine specimens) to the west of New Zealand, between 35° and 46° S, 156° and 167° E, in depths of 1647 - 4868 m.

Comments on “A new deep-water Astyris species (Buccinoidea: Columbellidae) from the southeastern Pacific” by Araya et al. 2016

Zootaxa ◽  
2017 ◽  
Vol 4247 (1) ◽  
pp. 55 ◽  
Author(s):  
JAVIER SELLANES
Keyword(s):  
New Species ◽  
Deep Water ◽  
Northern Chile ◽  
Future Analysis ◽  
Southeastern Pacific ◽  
Ecological Aspects ◽  
Future Work

The aim of this note is to clarify some aspects posed by Araya et al. (2016) in the description of the columbellid gastropod Astyris atacamensis for northern Chile, and also to complement it for providing further insight on important ecological aspects of the genus Astyris in the SE Pacific. Araya et al. (2016) fill an important gap, describing a species that in my opinion is important in many aspects, yet, they fail in connecting this new species with previous work in which this taxon has been mentioned. Araya et al. (2016) indicate that the genus has not been previously reported for the SE Pacific; however, Levin et al. (2002a) already mention finding Astyris permodesta (Dall, 1890) off Callao, Perú (~12°S). Astyris permodesta, originally described for the coast of California, is currently accepted under the genus Alia (Monsecour 2015). Although we still cannot confirm, most probably future analysis will prove that A. permodesta reported for Perú by Levin et al. (2002a) corresponds indeed to the new species Astyris atacamensis. Future work should elucidate the definitive placement of this species in either Alia or Astyris, but hereafter I will indistinctly use Astyris.  

The tectonic differences between the east and the west in the deep-water area of the northern South China Sea

2016 ◽  
Vol 35 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Zhongyu Xia ◽  
Zhifeng Wan ◽  
Xianqing Wang ◽  
Qiuhua Shi ◽  
Song Cai ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Deep Water ◽  
Northern South China Sea ◽  
Water Area ◽  
The West ◽  
China Sea ◽  
Deep Water Area

Neoglacial Ice Advance and Sediment Provenance Changes in Southwest Greenland and its Marginal Seas Traced by Radiogenic Isotopes

2020 ◽  
Author(s):  
Lina Madaj ◽  
Claude Hillaire-Marcel ◽  
Friedrich Lucassen ◽  
Simone Kasemann
Keyword(s):  
Marine Sediments ◽  
Deep Water ◽  
Radiogenic Isotopes ◽  
Labrador Sea ◽  
Coastal Current ◽  
Deep Water Formation ◽  
The West ◽  
The Holocene ◽  
Water Formation ◽  
Southwest Greenland

&lt;p&gt;Marine sediments from the West Greenland margin represent high-resolution archives of Holocene climate history, past ice sheet dynamics, changes in meltwater discharge and coastal current intensities. We investigate potential changes of sediment provenances using strontium (Sr) and neodymium (Nd) radiogenic isotopes as tracers for the origin and pathways of the silicate detrital fraction in marine sediments. Meltwater discharge and coastal currents are the most important transport pathways for detrital sediments into (northeast) Labrador Sea, which is an important pathway for freshwater from the Arctic Ocean and meltwater from the Greenland Ice Sheet to enter the North Atlantic, where deep water formation takes place. Variations in freshwater supply into Labrador Sea may influence deep water formation and therefore further circulation and climate patterns on a global scale.&lt;/p&gt;&lt;p&gt;The marine sediment record collected in Nuuk Trough, southwest Greenland, displays uniform isotopic compositions throughout most of the Holocene, indicating well mixed detrital material from local sources through meltwater discharge and distal sources transported via the West Greenland Current. From around 4 ka BP to present the composition of Nd isotopes reveals a steep (&amp;#949;Nd: -29 to -35) and the Sr isotope composition a slight (&lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr: 0.723 to 0.728) but pronounced shift. This time interval coincides with the transition into the Neoglacial time period [1], which is characterized by a significant drop in atmospheric temperatures [2], and the onset of the modern Labrador Sea circulation pattern (e.g. [3]). We suggest that the shift in Nd and Sr isotopes indicates a change towards less distal and more local sediment sources, possibly caused by enhanced erosion of the local bedrock during Neoglacial ice advance [4], along with a decrease in meltwater discharge [5] and coastal current strength, leading to a sediment delivery shift.&lt;/p&gt;&lt;p&gt;[1] Funder &amp; Fredskild (1989) Quaternary geology of Canada and Greenland, 775&amp;#8211;783. [2] Seidenkrantz et al. (2007) The Holocene 17, 387-401. [3] Fagel et al. (2004) Paleoceanography 19, PA3002. [4] Funder et al. (2011) Developments in Quaternary Sciences 15, 699-713, (and references therein). [5] M&amp;#248;ller et al. (2006) The Holocene 16, 685-695.&lt;/p&gt;

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