scholarly journals A new species of Ampharete (Annelida: Ampharetidae) from the West Shetland shelf (NE Atlantic Ocean), with two updated keys to the species of the genus in North Atlantic waters

2019 ◽  
Author(s):  
Julio Parapar ◽  
Juan MOREIRA ◽  
Ruth BARNICH
Keyword(s):  
North Atlantic ◽  
Small Body ◽  
New Taxon ◽  
Ne Atlantic ◽  
The West ◽  
The North ◽  
Joint Nature Conservation Committee ◽  
Ne Atlantic Ocean ◽  
Micro Morphology ◽  
A New Species

Ampharete oculicirrata sp. nov. (Annelida: Ampharetidae) is described from samples collected by the Joint Nature Conservation Committee and Marine Scotland Science, in the West Shetland Shelf NCMPA in the NE Atlantic. This species is characterised by a very small body size, thin and slender paleae, twelve thoracic and eleven abdominal uncinigers, presence of eyes both in the prostomium and the pygidium, the latter provided with a pair of long lateral cirri. The external micro-morphology of the new taxon was studied using scanning electron microscopy and compared with species described or reported from the North Atlantic. Two complementary keys to all species of Ampharete in the area are also provided.

scholarly journals The Combined Effects of SST and the North Atlantic Subtropical High-Pressure System on the Atlantic Basin Tropical Cyclone Interannual Variability

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 329
Author(s):  
Albenis Pérez-Alarcón ◽  
José C. Fernández-Alvarez ◽  
Rogert Sorí ◽  
Raquel Nieto ◽  
Luis Gimeno
Keyword(s):  
High Pressure ◽  
Interannual Variability ◽  
Central America ◽  
North Atlantic ◽  
The West ◽  
The Bahamas ◽  
Pressure System ◽  
North Atlantic Subtropical High ◽  
The North ◽  
The North Atlantic

The combined effect of the sea surface temperature (SST) and the North Atlantic subtropical high-pressure system (NASH) in the interannual variability of the genesis of tropical cyclones (TCs) and landfalling in the period 1980–2019 is explored in this study. The SST was extracted from the Centennial Time Scale dataset from the National Oceanic and Atmospheric Administration (NOAA), and TC records were obtained from the Atlantic Hurricane Database of the NOAA/National Hurricane Center. The genesis and landfalling regions were objectively clustered for this analysis. Seven regions of TC genesis and five for landfalling were identified. Intercluster differences were observed in the monthly frequency distribution and annual variability, both for genesis and landfalling. From the generalized least square multiple regression model, SST and NASH (intensity and position) covariates can explain 22.7% of the variance of the frequency of TC genesis, but it is only statistically significant (p < 0.1) for the NASH center latitude. The SST mostly modulates the frequency of TCs formed near the West African coast, and the NASH latitudinal variation affects those originated in the Lesser Antilles arc. For landfalling, both covariates explain 38.7% of the variance; however, significant differences are observed in the comparison between each region. With a statistical significance higher than 90%, SST and NASH explain 33.4% of the landfalling variability in the archipelago of the Bahamas and central–eastern region of Cuba. Besides, landfalls in the Gulf of Mexico and Central America seem to be modulated by SST. It was also found there was no statistically significant relationship between the frequency of genesis and landfalling with the NASH intensity. However, the NASH structure modulates the probability density of the TCs trajectory that make landfall once or several times in their lifetime. Thus, the NASH variability throughout a hurricane season affects the TCs trajectory in the North Atlantic basin. Moreover, we found that the landfalling frequency of TCs formed near the West Africa coast and the central North Atlantic is relatively low. Furthermore, the SST and NASH longitude center explains 31.6% (p < 0.05) of the variance of the landfalling intensity in the archipelago of the Bahamas, while the SST explains 26.4% (p < 0.05) in Central America. Furthermore, the 5-year moving average filter revealed decadal and multidecadal variability in both genesis and landfalling by region. Our findings confirm the complexity of the atmospheric processes involved in the TC genesis and landfalling.

scholarly journals DESIGN OF MAIN BREAKWATER AT SINES HARBOUR

1976 ◽  
Vol 1 (15) ◽  
pp. 143 ◽  
Author(s):  
John Dorrington Mettam
Keyword(s):  
North Atlantic ◽  
Government Agency ◽  
Irregular Waves ◽  
Regular Waves ◽  
The West ◽  
The North ◽  
Flume Tests ◽  
Wide Range ◽  
The Subject ◽  
Engineering Conference

In March 1972 the author's firm in association with two Portuguese firms of consulting engineers, Consulmar and Lusotecna, were appointed by the Portuguese Government agency Gabinete da Area de Sines to prepare designs for the construction of a new harbour at Sines on the west coast of Portugal. The location is shown in Figure 1. The main breakwater, which is the subject of this paper, is probably the largest breakwater yet built, being 2 km long and in depths of water of up to 50 m. It is exposed to the North Atlantic and has been designed for a significant wave height of 11 m. Dolos units invented by Merrifield (ref. 1) form the main armour. The project programme required that studies be first made of a wide range of alternative layouts for the harbour. After the client had decided on the layout to be adopted, documents were to be prepared to enable tenders for construction to be invited in January 1973. This allowed little time for the design to be developed and only one series of flume tests, using regular waves, was completed during this period. Further tests in the regular flume were completed during the tender period and a thorough programme of testing with irregular waves was commenced later in the year, continuing until August 1974 when the root of the breakwater was complete and the construction of the main cross-section was about to start. The model tests, which were carried out at the Laboratorio Nacional de Engenharia Civil in Lisbon, were reported by Morals in a paper presented to the 14th International Coastal Engineering Conference in 1974. (ref. 2)

A new species of amphipod, Megamphopus katagani sp. nov. (Crustacea: Peracarida: Photidae) from the Sea of Marmara (Turkey), with a key to the species of Megamphopus in the North Atlantic, Mediterranean and associated Seas

Zootaxa ◽  
2011 ◽  
Vol 2791 (1) ◽  
pp. 63 ◽  
Author(s):  
KEREM BAKIR ◽  
MURAT SEZGIN ◽  
ALAN A. MYERS
Keyword(s):  
New Species ◽  
North Atlantic ◽  
Sea Of Marmara ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
The North Atlantic ◽  
A New Species

A new species of amphipod, Megamphopus katagani sp. nov., is described from the sea of Marmara (Turkey). A key to the species of Megamphopus known from the North-East Atlantic, Mediterranean and associated seas is provided.

Notes on Fossil Chitons. 1. A new species of Lepidopleurus (Mollusca: Polyplacophora) from the Pleistocene of Salice (Sicily, Italy)

Zootaxa ◽  
2005 ◽  
Vol 821 (1) ◽  
pp. 1 ◽  
Author(s):  
BRUNO DELL’ANGELO ◽  
ANTONIO BONFITTO
Keyword(s):  
New Species ◽  
North Atlantic ◽  
Early Pleistocene ◽  
The North ◽  
The North Atlantic ◽  
A New Species

A new species of Polyplacophora (Mollusca) has been found in the Salice outcrop, in the Peloritain Mountains (Sicily, Italy), is attributed to the early Pleistocene. Lepidopleurus (Leptochiton) salicensis n.sp. is characterized by its uniformly sculptured tegmentum, with (well) raised, randomly distributed, neatly separated rounded/polygonal granules. The new species is compared with Lepidopleurus (Leptochiton) alveolus (M.Sars MS, Lovén, 1846), from the North Atlantic, and Lepidopleurus (Leptochiton) tavianii Dell’Angelo, Landau & Marquet, 2004, from the Pliocene of Estepona (Málaga, Spain).

Stratigraphy and timing of eolianite deposition on Rottnest Island, Western Australia

2003 ◽  
Vol 60 (2) ◽  
pp. 211-222 ◽  
Author(s):  
Paul J. Hearty
Keyword(s):  
North Atlantic ◽  
Late Quaternary ◽  
The West ◽  
Oxygen Isotope Stage ◽  
Amino Acid Racemization ◽  
Marine Deposits ◽  
The North ◽  
The North Atlantic ◽  
Radiometric Ages ◽  
Mis 5E

AbstractOver 100 whole-rock amino acid racemization (AAR) ratios from outcrops around Rottnest Island (32.0° S Latitude near Perth) indicate distinct pulses of eolian deposition during the late Quaternary. Whole-rock d-alloisoleucine/l-isoleucine (A/I) ratios from bioclastic carbonate deposits fall into three distinct modal classes or “aminozones.” The oldest, Aminozone E, averages 0.33 ± 0.04 (n = 21). Red palaeosol and thick calcrete generally cap the Aminozone E deposits. A younger Aminozone C averages 0.22 ± 0.03 (n = 63); comprising two submodes at 0.26 ± 0.01 (n = 14) and 0.21 ± 0.02 (n = 49). Multiple dune sets of this interval are interrupted by relatively weak, brown to tan “protosols.” A dense, dark brown rendzina palaeosol caps the Aminozone C succession. Ratios from Holocene dune and marine deposits (“Aminozone A”) center on 0.11 ± 0.02 (n = 15), comprising submodes of 0.13 ± 0.01 (9) and 0.09 ± 0.01 (6). Calibration of A/I averages from Aminozones E and A are provided by U/Th and 14C radiometric ages of 125,000 yr (marine oxygen isotope stage (MIS) 5e and 2000–6000 14C yr B.P. (MIS 1), respectively. The whole-rock A/I results support periodic deposition initiated during MIS 5e, continuing through MIS 5c, and then peaking at the end of MIS 5a, about 70,000–80,000 yr ago. Oceanographic evidence indicates the area was subjected to much colder conditions during MIS 2–4 (10,000 to 70,000 yr ago), greatly slowing the epimerization rate. Eolianite deposition resumed in the mid Holocene (∼6000 yr ago) up to the present. The A/I epimerization pathway constructed from Rottnest Island shows remarkable similarity to that of Bermuda in the North Atlantic (32° N Latitude). These findings suggest that, like Bermuda, the eolian activity on Rottnest occurred primarily during or shortly after interglacial highstands when the shoreline was near the present datum, rather than during glacial lowstands when the coastline was positioned 10–20 km to the west.

On a new species of Siboglinum (Pogonophora), found on both sides of the North Atlantic

1963 ◽  
Vol 43 (2) ◽  
pp. 513-517 ◽  
Author(s):  
Eve C. Southward
Keyword(s):  
New Species ◽  
Shallow Water ◽  
North Atlantic ◽  
Related Species ◽  
The North ◽  
The Pacific ◽  
The North Atlantic ◽  
A New Species

A description is given of Siboglinum holmei sp.nov., a shallow-water Atlantic species. It is compared with S. caulleryi, a related species from the Pacific.

A new species of Hyattechinus (Echinoidea) from the type Devonian of the United Kingdom and implications for the distribution of Devonian proterocidarid echinoids

2018 ◽  
Vol 156 (5) ◽  
pp. 801-810 ◽  
Author(s):  
JEFFREY R. THOMPSON ◽  
TIMOTHY A. M. EWIN
Keyword(s):  
New Species ◽  
Sea Urchins ◽  
Appalachian Basin ◽  
Upper Devonian ◽  
Late Devonian ◽  
New Taxon ◽  
The North ◽  
Late Palaeozoic ◽  
Diversity Dynamics ◽  
A New Species

AbstractMany of the most diverse clades of Late Palaeozoic echinoids (sea urchins) originated in the Devonian period. Our understanding of diversity dynamics of these Late Palaeozoic clades are thus informed by new systematic descriptions of some of their earliest members. The Proterocidaridae are a diverse and morphologically distinct clade of stem group echinoids with flattened tests and enlarged adoral pore pairs, which are first known from the Upper Devonian. We herein report on a new species of Hyattechinus, Hyattechinus anglicus n. sp., from the Upper Devonian of the North Devon Basin, Devon, UK. This is the first Devonian Hyattechinus known from outside of the Appalachian Basin, USA, and provides novel information regarding the palaeogeographic and stratigraphic distribution of proterocidarids in Late Devonian times. We additionally update the stratigraphic distribution of Devonian Hyattechinus from the Appalachian Basin, following recent biostratigraphic resolution of their occurrences. Hyattechinus appears to have been present in the Rheic echinoderm fauna during Late Devonian times, and comparison of the palaeoenvironmental setting of Hyattechinus anglicus with that of other Hyattechinus from the Famennian of the Appalachian Basin suggests that the genus may have preferred siliciclastic settings. Furthermore, this new taxon increases the diversity of echinoids from the Upper Devonian of Devon to three species.

Le controle du socle dans l'évolution de la sedimentation en Manche occidentale apres le Paléozoïque

1975 ◽  
Vol 279 (1288) ◽  
pp. 137-143 ◽  
Keyword(s):  
North Atlantic ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
The West ◽  
The North ◽  
The North Atlantic ◽  
The Difference ◽  
Cenozoic Sediments ◽  
Two Sides

The estimates of the thickness of the Mesozoic and Cenozoic sediments found in the western Channel show that the deposition of these sediments was controlled by two independent processes. (1) In the longitudinal direction, the displacement of maximum sedimentation, from east to west is entirely dependent on the opening of the North Atlantic. (2) In a transverse direction, it is probable that the difference of subsidence between the two sides of the Aurigny—Ouessant fault originated from the fracturing of the original Atlantic rift in the Western Approaches. Transverse compressions and extensions have disturbed the continual depression of the Channel towards the west.

scholarly journals Stalked crinoids (Echinodermata) collected by the R/V Polarstern and Meteor in the south Atlantic and in Antarctica

Zootaxa ◽  
2012 ◽  
Vol 3425 (1) ◽  
pp. 1 ◽  
Author(s):  
MARC ELÉAUME ◽  
JENS-MICHAEL BOHN ◽  
MICHEL ROUX ◽  
NADIA AMÉZIANE
Keyword(s):  
North Atlantic ◽  
Deep Sea ◽  
South Atlantic ◽  
The South ◽  
The West ◽  
Walvis Ridge ◽  
The North ◽  
West Antarctic ◽  
Stalked Crinoids ◽  
Hard Substrates

During the last decades, R/V Meteor and R/V Polarstern deep-sea investigations in the south Atlantic and neighbouringSouthern Ocean collected new samples of stalked crinoids belonging to the families Bathycrinidae, Phrynocrinidae andHyocrinidae which are herein described. The species found are Bathycrinus australis A.H. Clark, 1907b (the most abun-dant), Dumetocrinus aff. antarcticus (Bather, 1908), Hyocrinus bethellianus Thomson, 1876, Feracrinus heinzelleri newspecies, and Porphyrocrinus cf. incrassatus (Gislén, 1933). As only stalk fragments of bathycrinids were frequently col-lected, a distinction between the two Atlantic species B. australis and B. aldrichianus is proposed using characters of co-lumnal articulations. A few specimens attributed to Porphyrocrinus cf. incrassatus, Hyocrinus bethellianus and Hyocrinussp. collected by the N/O Jean Charcot on the Walvis Ridge are also described, plus a new specimen of Porphyrocrinusincrassatus collected in the central mid-Atlantic. Biogeography and close affinities between species in the genera Bathy-crinus and Porphyrocrinus suggest an Antarctic origin of some stalked crinoids among the north Atlantic deep-sea fauna.The presence of B. australis in both the Angola and Cape basins suggests that the Walvis Ridge is not a bio-geographicalbarrier for this relatively eurybathic species, which can attach to hard substrates as well as anchor in sediment. The genusDumetocrinus seems to be an example of colonization of the west Antarctic platform from deeper environment where its ancestor lived.

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