scholarly journals Exploitation of the Small Whales in the North Atlantic

Oryx ◽  
1965 ◽  
Vol 8 (3) ◽  
pp. 185-193
Author(s):  
Arthur G. Bourne
Keyword(s):  
North Atlantic ◽  
Rapid Decline ◽  
Valuable Resource ◽  
The North ◽  
History Of ◽  
The North Atlantic ◽  
The Mediterranean ◽  
To Come ◽  
Mediterranean And Black Seas

For several hundred years the small whales of the North Atlantic and the Mediterranean and Black Seas have been hunted with varying degrees of intensity. All too often the story has been one of overhunting followed by rapid decline of stocks, but so little is known about these small whales that today it is impossible to assess their populations or the effects of present hunting on the stocks. The author recounts the history of eight species of small whale and urges the need for more research to ensure planned cropping of a valuable resource. A Canadian proposal for whale hunting as a sport is perhaps a sign of a new danger to come.

The Metasomatized Mantle beneath the North Atlantic Craton: Insights from Peridotite Xenoliths of the Chidliak Kimberlite Province (NE Canada)

2019 ◽  
Vol 60 (10) ◽  
pp. 1991-2024 ◽  
Author(s):  
M G Kopylova ◽  
E Tso ◽  
F Ma ◽  
J Liu ◽  
D G Pearson
Keyword(s):  
North Atlantic ◽  
Thermal State ◽  
Mineral Chemistry ◽  
Mantle Metasomatism ◽  
Labrador Sea ◽  
The North ◽  
Rock Types ◽  
History Of ◽  
The North Atlantic ◽  
North Atlantic Craton

Abstract We studied the petrography, mineralogy, thermobarometry and whole-rock chemistry of 120 peridotite and pyroxenite xenoliths collected from the 156–138 Ma Chidliak kimberlite province (Southern Baffin Island). Xenoliths from pipes CH-1, -6, -7 and -44 are divided into two garnet-bearing series, dunites–harzburgites–lherzolites and wehrlites–olivine pyroxenites. Both series show widely varying textures, from coarse to sheared, and textures of late formation of garnet and clinopyroxene. Some samples from the lherzolite series may contain spinel, whereas wehrlites may contain ilmenite. In CH-6, rare coarse samples of the lherzolite and wehrlite series were derived from P = 2·8 to 5·6 GPa, whereas predominant sheared and coarse samples of the lherzolite series coexist at P = 5·6–7·5 GPa. Kimberlites CH-1, -7, -44 sample mainly the deeper mantle, at P = 5·0–7·5 GPa, represented by coarse and sheared lherzolite and wehrlite series. The bulk of the pressure–temperature arrays defines a thermal state compatible with 35–39 mW m–2 surface heat flow, but a significant thermal disequilibrium was evident in the large isobaric thermal scatter, especially at depth, and in the low thermal gradients uncharacteristic of conduction. The whole-rock Si and Mg contents of the Chidliak xenoliths and their mineral chemistry reflect initial high levels of melt depletion typical of cratonic mantle and subsequent refertilization in Ca and Al. Unlike the more orthopyroxene-rich mantle of many other cratons, the Chidliak mantle is rich (∼83 vol%) in forsteritic olivine. We assign this to silicate–carbonate metasomatism, which triggered wehrlitization of the mantle. The Chidliak mantle resembles the Greenlandic part of the North Atlantic Craton, suggesting the former contiguous nature of their lithosphere before subsequent rifting into separate continental fragments. Another, more recent type of mantle metasomatism, which affected the Chidliak mantle, is characterized by elevated Ti in pyroxenes and garnet typical of all rock types from CH-1, -7 and -44. These metasomatic samples are largely absent from the CH-6 xenolith suite. The Ti imprint is most intense in xenoliths derived from depths equivalent to 5·5–6·5 GPa where it is associated with higher strain, the presence of sheared samples of the lherzolite series and higher temperatures varying isobarically by up to 200 °C. The horizontal scale of the thermal-metasomatic imprint is more ambiguous and could be as regional as tens of kilometers or as local as <1 km. The time-scale of this metasomatism relates to a conductive length-scale and could be as short as <1 Myr, shortly predating kimberlite formation. A complex protracted metasomatic history of the North Atlantic Craton reconstructed from Chidliak xenoliths matches emplacement patterns of deep CO2-rich and Ti-rich magmatism around the Labrador Sea prior to the craton rifting. The metasomatism may have played a pivotal role in thinning the North Atlantic Craton lithosphere adjacent to the Labrador Sea from ∼240 km in the Jurassic to ∼65 km in the Paleogene.

North Atlantic Oscillation-related impacts on precipitation over the Italian Peninsula during the 1979-2020 period

2021 ◽  
Author(s):  
Paula Lorenzo Sánchez ◽  
Leonardo Aragão
Keyword(s):  
High Resolution ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Mediterranean Region ◽  
Italian Peninsula ◽  
The North ◽  
Nao Index ◽  
The North Atlantic ◽  
The Mediterranean ◽  
Resolution Dataset

<p>The North Atlantic Oscillation (NAO) has been widely recognized as one of the main patterns of atmospheric variability over the northern hemisphere, helping to understand variations on the North Atlantic Jet (NAJ) position and its influence on storm-tracks, atmospheric blocking and Rossby Wave breaking. Among several relevant teleconnection patterns identified through different timescales, the most prominent ones are found for northern Europe during winter months, when positive (negative) phases of NAO are related to wetter (drier) conditions. Although it is not well defined yet, an opposite connection is observed for the Mediterranean region, where negative NAO values are often associated with high precipitation. Therefore, the main goal of this study is to identify which regions and periods of the year are the most susceptible to abundant NAO-related precipitation throughout the Italian Peninsula. For doing so, the last 42 years period (1979-2020) was analysed using the Fifth Generation ECMWF Atmospheric ReAnalysis of the Global Climate (ERA5). The NAO index was calculated using the Mean Sea Level Pressure (MSLP) extracted from the nearest gridpoints to Reykjavik, Ponta Delgada, Lisbon and Gibraltar, with a time resolution of one hour and horizontal spatial resolution of 0.25ºx0.25º. Both NAO index and MSLP time series were validated for different timescales (hourly, daily, monthly and seasonal) using the Automated Surface Observing System data and the Climatic Research Unit (CRU) high-resolution dataset (based on measured data). High correlations, ranging from 0.92 to 0.98, were found for all stations, timescales and evaluated parameters. To quantify the influence of NAO over the Mediterranean region, the monthly averaged ERA5 ‘total precipitation’ data over the Italian Peninsula [35-48º N; 5-20º E] were used. As expected, the results concerning NAO x Precipitation presented the best correlations when analysed monthly, confirming some of the already known NAO signatures over the Italian Peninsula: higher correlations during winter and over the Tyrrhenian coast, and lower correlations during summer and over the Apennines, the Adriatic Sea and the Ionian Sea. On the other hand, the precipitation over the Alps and the Tunisian coast presented a remarkable signature of positive NAO values that, despite a lower statistical significance (85-90%), is in agreement with recent findings of observational studies. In addition, significant negative correlations were identified for the spring and autumn months over the Tyrrhenian area. Among those, the high correlations found during May are particularly interesting, as they follow the behaviour described in recent studies performed using the same high-resolution dataset (ERA5), which have identified an increased number of cyclones over the Mediterranean during this month. This connection suggests that NAO could also be used to explore the potential penetration of the North Atlantic depressions into the Mediterranean Basin. </p><p>Keywords: NAO; Teleconnections; ERA5; ReAnalysis; Mediterranean; Climatology.</p>

scholarly journals First monk seal from the Southern Hemisphere rewrites the evolutionary history of true seals

2020 ◽  
Vol 287 (1938) ◽  
pp. 20202318
Author(s):  
James P. Rule ◽  
Justin W. Adams ◽  
Felix G. Marx ◽  
Alistair R. Evans ◽  
Alan J. D. Tennyson ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
North Atlantic ◽  
Marine Mammals ◽  
Evolutionary History ◽  
Major Change ◽  
The North ◽  
History Of ◽  
Entire History ◽  
The North Atlantic ◽  
Monk Seals

Living true seals (phocids) are the most widely dispersed semi-aquatic marine mammals, and comprise geographically separate northern (phocine) and southern (monachine) groups. Both are thought to have evolved in the North Atlantic, with only two monachine lineages—elephant seals and lobodontins—subsequently crossing the equator. The third and most basal monachine tribe, the monk seals, have hitherto been interpreted as exclusively northern and (sub)tropical throughout their entire history. Here, we describe a new species of extinct monk seal from the Pliocene of New Zealand, the first of its kind from the Southern Hemisphere, based on one of the best-preserved and richest samples of seal fossils worldwide. This unanticipated discovery reveals that all three monachine tribes once coexisted south of the equator, and forces a profound revision of their evolutionary history: rather than primarily diversifying in the North Atlantic, monachines largely evolved in the Southern Hemisphere, and from this southern cradle later reinvaded the north. Our results suggest that true seals crossed the equator over eight times in their history. Overall, they more than double the age of the north–south dichotomy characterizing living true seals and confirms a surprisingly recent major change in southern phocid diversity.

A connected history of political economy in Asia and Europe, ca 1750–1914

2020 ◽  
pp. 1-2
Author(s):  
Alessandro Stanziani
Keyword(s):  
Political Economy ◽  
Ottoman Empire ◽  
North Atlantic ◽  
Western Europe ◽  
Economic Thought ◽  
The North ◽  
History Of ◽  
The North Atlantic ◽  
History Of Political Economy ◽  
Political Economic

The history of political-economic thought has been built up over the centuries with a uniform focus on European and North American thinkers. Intellectuals beyond the North Atlantic have been largely understood as the passive recipients of already formed economic categories and arguments. This view has often been accepted not only by scholars and observers in Europe but also in many other places such as Russia, India, China, Japan, and the Ottoman Empire. In this regard, the articles included in this collection explicitly differentiate from this diffusionist approach (“born in Western Europe, then flowed everywhere else”).

Second reply to the comment by Romero and Kannada on “Genetic analysis of 16th-century whale bones prompts a revision of the impact of Basque whaling on right and bowhead whales in the western North Atlantic”Appears in Can. J. Zool. 84(7): 1059–1065.

2008 ◽  
Vol 86 (1) ◽  
pp. 76-79 ◽  
Author(s):  
Jeff W. Higdon
Keyword(s):  
Genetic Analysis ◽  
North Atlantic ◽  
16Th Century ◽  
Bowhead Whales ◽  
Potential Value ◽  
The North ◽  
The Pacific ◽  
History Of ◽  
The North Atlantic ◽  
The Impact

The comments by A. Romero and S. Kannada (2006. Can. J. Zool. 84: 1059–1065) provide a brief summary of North Atlantic whaling history as a critique of T. Rastogi et al. (2004. Can. J. Zool. 82: 1647–1654) . However, they fall far short of providing an accurate review of whaling history in this region. The authors present a number of factual errors, misuse several key sources, and make significant omissions, ultimately defeating the purpose of providing information to biologists, managers, and historians. In this comment I highlight the mistakes in their representation of the history of North Atlantic whaling for bowhead whales ( Balaena mysticetus L., 1758). There are unacceptable errors for most nations covered, and for American whaling in particular. The authors assert that over 30 000 bowhead whales were landed by Yankee whalers in the North Atlantic when the vast majority were in fact taken on the Pacific grounds. Although a summary of whaling history is an admirable goal and of potential value, it is unfortunate that the authors missed such an opportunity by failing to adequately research this topic, failing to include important citations, and by including sources that do not provide the information indicated. Providing a whaling summary with such errors and omissions only adds further confusion to an already confusing theme.

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