scholarly journals Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018

Ocean Science ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 17-34
Author(s):  
Lucia Pineau-Guillou ◽  
Pascal Lazure ◽  
Guy Wöppelmann
Keyword(s):  
Sea Level ◽  
North Atlantic ◽  
Large Scale ◽  
Low Frequency ◽  
Underlying Mechanism ◽  
East Atlantic ◽  
North West ◽  
North East ◽  
The North ◽  
The North Atlantic

Abstract. We investigated the long-term changes of the principal tidal component M2 along North Atlantic coasts, from 1846 to 2018. We analysed 18 tide gauges with time series starting no later than 1940. The longest is Brest with 165 years of observations. We carefully processed the data, particularly to remove the 18.6-year nodal modulation. We found that M2 variations are consistent at all the stations in the North-East Atlantic (Cuxhaven, Delfzijl, Hoek van Holland, Newlyn, Brest), whereas some discrepancies appear in the North-West Atlantic. The changes started long before the 20th century and are not linear. The secular trends in M2 amplitude vary from one station to another; most of them are positive, up to 2.5 mm/yr at Wilmington since 1910. Since 1990, the trends switch from positive to negative values in the North-East Atlantic. Concerning the possible causes of the observed changes, the similarity between the North Atlantic Oscillation and M2 variations in the North-East Atlantic suggests a possible influence of the large-scale atmospheric circulation on the tide. Our statistical analysis confirms large correlations at all the stations in the North-East Atlantic. We discuss a possible underlying mechanism. A different spatial distribution of mean sea level (corresponding to water depth) from one year to another, depending on the low-frequency sea-level pressure patterns, could impact the propagation of the tide in the North Atlantic basin. However, the hypothesis is at present unproven.

scholarly journals Climate-scale changes of the semidiurnal tide over the North Atlantic coasts from 1846 to 2018

2020 ◽  
Author(s):  
Lucia Pineau-Guillou ◽  
Pascal Lazure ◽  
Guy Wöppelmann
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Low Frequency ◽  
Underlying Mechanism ◽  
East Atlantic ◽  
North West ◽  
North East ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract. We investigated the long-term changes of the principal tidal component M2 over the North Atlantic coasts, from 1846 to 2018. We analysed 9 tide gauges with time series starting no later than 1920. The longest is Brest with 165 years of observations. We carefully processed the data, particularly to remove the 18.6-year nodal modulation. We found that M2 variations are consistent at all the stations in the North East Atlantic (Newlyn, Brest, Cuxhaven), whereas some discrepancies appear in the North West Atlantic. The changes started long before the XXth century, and are not linear. The trends vary from a station to another; they are overall positive, up to 0.7 mm/yr. Since 1990, the trends switch from positive to negative values. Concerning the possible causes of the observed changes, the similarity between the North Atlantic Oscillation and M2 variations in the North East Atlantic suggests a possible influence of the large-scale atmospheric circulation on the tide. We discuss a possible underlying mechanism. A different spatial distribution of water heights from one year to another, depending on the low-frequency sea-level pressure patterns, could impact the propagation of the tide in the North Atlantic basin. However, the hypothesis is at present unproven.

scholarly journals Population genetics meets phylogenetics: new insights into the relationships among members of the genus Euthynnus (family Scombridae)

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Judith Ollé ◽  
Laura Vilà-Valls ◽  
Jaime Alvarado-Bremer ◽  
Genoveva Cerdenares ◽  
Thuy Yen Duong ◽  
...  
Keyword(s):  
North Atlantic ◽  
Genetic Divergence ◽  
East Atlantic ◽  
North West ◽  
North East ◽  
The North ◽  
Worldwide Distribution ◽  
Allopatric Species ◽  
The North Atlantic ◽  
High Level

AbstractEuthynnus (family Scombridae) is a genus of marine pelagic fish species with a worldwide distribution that comprises three allopatric species: E. alletteratus, E. affinis and E. lineatus. All of them targeted by artisanal and commercial fisheries. We analyzed 263 individuals from Atlantic and Pacific Oceans using two genetic markers, the mtDNA Control Region (350 bp) and nuclear calmodulin (341 bp). The results obtained challenge the phylogeny of this group. We found a deep genetic divergence, probably at species level, within E. alletteratus, between the North Atlantic-Mediterranean and the Tropical East Atlantic. This deep genetic divergence was tested with several species delimitation methods. This complete phylogeographic association between the North Atlantic and the Tropical East Atlantic support the hypothesis of two cryptic species. In addition, population genetic heterogeneity was detected between the North East Atlantic–Mediterranean and North West Atlantic regions. Our results indicate two scales of differentiation in what is currently considered a single population. Accordingly, for management purposes, the populations of E. alletteratus, should be divided into a minimum of three management units. On the other hand, the high level of differentiation found in E. alletteratus contrasts with the shallow genetic divergence of E. affinis and E. lineatus.

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.

Ophlitaspongia and Ophlitaspongia papilla reinstated, and a new species of Ophlitaspongia described (Porifera: Demospongiae: Microcionidae)

1999 ◽  
Vol 79 (4) ◽  
pp. 609-620 ◽  
Author(s):  
C.M. Howson ◽  
S.J. Chambers
Keyword(s):  
New Species ◽  
North Atlantic ◽  
Deep Water ◽  
The Other ◽  
East Atlantic ◽  
Halichondria Panicea ◽  
North East ◽  
The North ◽  
The North Atlantic ◽  
A New Species

A new species of Ophlitaspongia (Porifera: Microcionidae) from wave-exposed sublittoral rock in the north-east Atlantic is described and compared to the two other species recorded from the genus in the north-east Atlantic. The species known as Ophlitaspongia seriata is considered to be a junior synonym of Halichondria panicea. Consequently, the name O. papilla has been reinstated. The other recorded species O. basifixa, is from deep water. Ophlitaspongia basifixa has characters which differentiate it from Ophlitaspongia sp. nov. The genus Ophlitaspongia has been separated from related genera and reinstated for species in the North Atlantic.

scholarly journals The North Atlantic Oscillation Response to Large-Scale Atmospheric Anomalies in the Northeastern Pacific

2013 ◽  
Vol 70 (9) ◽  
pp. 2854-2874 ◽  
Author(s):  
Marie Drouard ◽  
Gwendal Rivière ◽  
Philippe Arbogast
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Wave Breaking ◽  
Large Scale ◽  
Wave Train ◽  
Low Frequency ◽  
The North ◽  
Northeastern Pacific ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract Ingredients in the North Pacific flow influencing Rossby wave breakings in the North Atlantic and the intraseasonal variations of the North Atlantic Oscillation (NAO) are investigated using both reanalysis data and a three-level quasigeostrophic model on the sphere. First, a long-term run is shown to reproduce the observed relationship between the nature of the synoptic wave breaking and the phase of the NAO. Furthermore, a large-scale, low-frequency ridge anomaly is identified in the northeastern Pacific in the days prior to the maximum of the positive NAO phase both in the reanalysis and in the model. A large-scale northeastern Pacific trough anomaly is observed during the negative NAO phase but does not systematically precede it. Then, short-term linear and nonlinear simulations are performed to understand how the large-scale ridge anomaly can act as a precursor of the positive NAO phase. The numerical setup allows for analysis of the propagation of synoptic waves in the eastern Pacific in the presence of a large-scale ridge or trough anomaly and their downstream impact onto the Atlantic jet when they break. The ridge acts in two ways. First, it tends to prevent the downstream propagation of small waves compared to long waves. Second, it deflects the propagation of the wave trains in such a way that they mainly propagate equatorward in the Atlantic. The two modes of action favor the anticyclonic wave breaking and, therefore, the positive NAO phase. With the trough, the wave train propagation is more zonal, disturbances are more meridionally elongated, and cyclonic wave breaking is more frequent in the Atlantic than in the ridge case.

Latitudinal Displacements of the Gulf Stream and the Abundance of Plankton in the North-East Atlantic

1992 ◽  
Vol 72 (4) ◽  
pp. 919-921 ◽  
Author(s):  
A. H. Taylor ◽  
J. M. Colebrook ◽  
J. A. Stephens ◽  
N. G. Baker
Keyword(s):  
Time Series ◽  
North Atlantic ◽  
Gulf Stream ◽  
Storm Tracks ◽  
British Isles ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
The North Atlantic ◽  
North Wall

An earlier time-series of the annual mean latitude of the north wall of the Gulf Stream is updated to give a series of values from 1966 to 1990. The trend is similar to those seen in plankton from the Continuous Plankton Recorder Survey around the British Isles. This connection may reflect the displacement of storm tracks across the North Atlantic.

Management and Developement of Fisheries in the North Atlantic

1973 ◽  
Vol 30 (12) ◽  
pp. 2402-2418 ◽  
Author(s):  
G. Möcklinghoff
Keyword(s):  
Fish Species ◽  
North Atlantic ◽  
Mesh Size ◽  
Fishing Effort ◽  
Conceptual Basis ◽  
East Atlantic ◽  
International Council ◽  
North East ◽  
The North ◽  
The North Atlantic

The "conventional" fish species of the North Atlantic are mostly being fully utilized or nearly so, some having been overexploited in recent years. Recommendations for management are made by the International Commission for the Northwest Atlantic Fisheries (ICNAF) and the North East Atlantic Fisheries Commission (NEAFC). The factual and conceptual basis for management is provided by the scientists of many nations, coordinated by ICNAF and by the International Council for the Exploration of the Sea (ICES). The need in nearly every major North Atlantic fishery is to limit fishing effort, which in practical terms means allocating quotas to states. Such action has been initiated by ICNAF and is under active consideration by NEAFC. The process would have been easier if it had been begun a few years earlier, before several major stocks became depressed, but since new ground is being broken internationally the delay was almost inevitable. Regulations of mesh size in trawls have been in force in both areas for some years. These were successful in providing a greater yield from each year-class of groundfish as it appeared, but could not by themselves ensure a breeding stock adequate for optimum reproduction. Problems of allocation of quotas, of enforcement, and of national claims for the extension of exclusive fishing zones will require continued discussion and goodwill among the nations in the years ahead.

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