The Mud-Dwelling Hydrozoan Boreohydra simplex in the Western North Atlantic

1974 ◽  
Vol 31 (10) ◽  
pp. 1666-1667
Author(s):  
Dale R. Calder
Keyword(s):  
North Atlantic ◽  
South Atlantic ◽  
The South ◽  
Eastern Canada ◽  
South Georgia ◽  
The North ◽  
The North Atlantic

Boreohydra simplex was collected at a depth of 400 m in Cabot Strait, eastern Canada; this solitary, mud-dwelling hydroid is previously unreported from the western North Atlantic. Elsewhere, it has been found along the coasts of Scandinavia, Britain, and Iceland in the North Atlantic, and from South Georgia in the South Atlantic.

Millennial-scale climate changes on South Georgia, Southern Ocean

2003 ◽  
Vol 59 (3) ◽  
pp. 470-475 ◽  
Author(s):  
Gunhild C. Rosqvist ◽  
Pernilla Schuber
Keyword(s):  
Southern Hemisphere ◽  
North Atlantic ◽  
Climate Changes ◽  
South Atlantic ◽  
The South ◽  
Temperature Changes ◽  
South Georgia ◽  
The North ◽  
Suitable Site ◽  
Millennial Scale

AbstractThe location of South Georgia (54°S, 36°W) makes it a suitable site for the study of the climatic connections between temperate and polar environments in the Southern Hemisphere. Because the mass balance of the small cirque glaciers on South Georgia primarily responds to changes in summer temperature they can provide records of changes in the South Atlantic Ocean and atmospheric circulation. We use grey scale density, weight-loss-on-ignition, and grain size analyses to show that the proportion of glacially eroded sediments to organic sediments in Block Lake was highly variable during the last 7400 cal yr B.P. We expect that the glacial signal is clearly detectable above noise originating from nonglacial processes and assume that an increase in glacigenic sediment deposition in Block Lake has followed Holocene glacier advances. We interpret proglacial lake sediment sequences in terms of summer climate warming and cooling events. Prominent millennial-scale features include cooling events between 7200 and 7000, 5200 and 4400, and 2400 and 1600 cal yr B.P. and after 1000 cal yr B.P. Comparison with other terrestrial and marine records reveals that the South Georgian record captures all the important changes in Southern Hemisphere Holocene climate. Our results reveal a tentative coupling between climate changes in the South Atlantic and North Atlantic because the documented temperature changes on South Georgia are anti-phased to those in the North Atlantic.

Diaphus hudsoni (Pisces: Myctophidae), a new lanternfish from the South Atlantic Ocean

1976 ◽  
Vol 54 (9) ◽  
pp. 1538-1541
Author(s):  
R. E. Zurbrigg ◽  
W. B. Scott
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
The South ◽  
Gill Rakers ◽  
Royal Ontario Museum ◽  
The North ◽  
The North Atlantic

A new myctophid species, Diaphus hudsoni, was captured in the South Atlantic Ocean, and is described. It is similar to Diaphus subtilis Nafpaktitis, which occurs in the North Atlantic Ocean, but is definitely distinct with its slender, more numerous gill rakers (total 23–25), and non-continuous AOp–Prc series. The AO series numbers 5 + 5–6. The holotype is deposited in the Royal Ontario Museum, ROM 27569.

scholarly journals Atmospheric Origins of Variability in the South Atlantic Meridional Overturning Circulation

2019 ◽  
Vol 32 (5) ◽  
pp. 1483-1500 ◽  
Author(s):  
Timothy Smith ◽  
Patrick Heimbach
Keyword(s):  
North Atlantic ◽  
Atlantic Meridional Overturning Circulation ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
The South ◽  
Overturning Circulation ◽  
The North ◽  
Meridional Overturning ◽  
Atmospheric State ◽  
The North Atlantic

Abstract Insights from the RAPID–MOCHA observation network in the North Atlantic have motivated a recent focus on the South Atlantic, where water masses are exchanged with neighboring ocean basins. In this study, variability in the South Atlantic meridional overturning circulation (SAMOC) at 34°S is attributed to global atmospheric forcing using an inverse modeling approach. The sensitivity of the SAMOC to atmospheric state variables is computed with the adjoint of the Massachusetts Institute of Technology general circulation model, which is fit to 20 years of observational data in a dynamically consistent framework. The dynamical pathways highlighted by these sensitivity patterns show that the domain of influence for the SAMOC is broad, covering neighboring ocean basins even on short time scales. This result differs from what has previously been shown in the North Atlantic, where Atlantic meridional overturning circulation (AMOC) variability is largely governed by dynamics confined to that basin. The computed sensitivities are convolved with surface atmospheric state variability from ERA-Interim to attribute the influence of each external forcing variable (e.g., wind stress, precipitation) on the SAMOC from 1992 to 2011. Here, local wind stress perturbations are shown to dominate variability on seasonal time scales while buoyancy forcing plays a minor role, confirming results from past forward perturbation experiments. Interannual variability, however, is shown to have originated from remote locations across the globe, including a nontrivial component originating from the tropical Pacific. The influence of atmospheric forcing emphasizes the importance of continuous widespread observations of the global atmospheric state for attributing observed AMOC variability.

Observed seasonal regimes of North-South Atlantic Ocean interbasin exchange

2019 ◽  
Author(s):  
Hamed D. Ibrahim
Keyword(s):  
North Atlantic ◽  
Climate Models ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
Volume Flux ◽  
The South ◽  
The North ◽  
Basin Scale ◽  
Interbasin Exchange ◽  
North And South

North and South Atlantic lateral volume exchange is a key component of the Atlantic Meridional Overturning Circulation (AMOC) embedded in Earth’s climate. Northward AMOC heat transport within this exchange mitigates the large heat loss to the atmosphere in the northern North Atlantic. Because of inadequate climate data, observational basin-scale studies of net interbasin exchange between the North and South Atlantic have been limited. Here ten independent climate datasets, five satellite-derived and five analyses, are synthesized to show that North and South Atlantic climatological net lateral volume exchange is partitioned into two seasonal regimes. From late-May to late-November, net lateral volume flux is from the North to the South Atlantic; whereas from late-November to late-May, net lateral volume flux is from the South to the North Atlantic. This climatological characterization offers a framework for assessing seasonal variations in these basins and provides a constraint for climate models that simulate AMOC dynamics.

scholarly journals Influence of the North Atlantic oscillation on the atmospheric levels of benzo[a]pyrene over Europe

2021 ◽  
Author(s):  
Pedro Jiménez-Guerrero ◽  
Nuno Ratola
Keyword(s):  
Spatial Pattern ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Transport Model ◽  
Regional Scale ◽  
The South ◽  
Climatic Fluctuations ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

AbstractThe atmospheric concentration of persistent organic pollutants (and of polycyclic aromatic hydrocarbons, PAHs, in particular) is closely related to climate change and climatic fluctuations, which are likely to influence contaminant’s transport pathways and transfer processes. Predicting how climate variability alters PAHs concentrations in the atmosphere still poses an exceptional challenge. In this sense, the main objective of this contribution is to assess the relationship between the North Atlantic Oscillation (NAO) index and the mean concentration of benzo[a]pyrene (BaP, the most studied PAH congener) in a domain covering Europe, with an emphasis on the effect of regional-scale processes. A numerical simulation for a present climate period of 30 years was performed using a regional chemistry transport model with a 25 km spatial resolution (horizontal), higher than those commonly applied. The results show an important seasonal behaviour, with a remarkable spatial pattern of difference between the north and the south of the domain. In winter, higher BaP ground levels are found during the NAO+ phase for the Mediterranean basin, while the spatial pattern of this feature (higher BaP levels during NAO+ phases) moves northwards in summer. These results show deviations up to and sometimes over 100% in the BaP mean concentrations, but statistically significant signals (p<0.1) of lower changes (20–40% variations in the signal) are found for the north of the domain in winter and for the south in summer.

scholarly journals Impact of Agulhas Leakage on the Atlantic Overturning Circulation in the CCSM4

2014 ◽  
Vol 27 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Wilbert Weijer ◽  
Erik van Sebille
Keyword(s):  
North Atlantic ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
Overturning Circulation ◽  
Climate System Model ◽  
The North ◽  
Salinity Variability ◽  
Meridional Overturning ◽  
The North Atlantic ◽  
The Impact

Abstract The impact of Agulhas leakage variability on the strength of the Atlantic meridional overturning circulation (AMOC) in the Community Climate System Model, version 4 (CCSM4) is investigated. In this model an advective connection exists that transports salinity anomalies from the Agulhas region into the North Atlantic on decadal (30–40 yr) time scales. However, there is no identifiable impact of Agulhas leakage on the strength of the AMOC, suggesting that the salinity variations are too weak to significantly modify the stratification in the North Atlantic. It is argued that this study is inconclusive with respect to an impact of Agulhas leakage on the AMOC. Salinity biases leave the South Atlantic and Indian Oceans too homogeneous, in particular erasing the observed salinity front in the Agulhas retroflection region. Consequently, salinity variability in the southeastern South Atlantic is found to be much weaker than observed.

scholarly journals Inferring marine distribution of Canadian and Irish Atlantic salmon (Salmo salar L.) in the North Atlantic from tissue concentrations of bio-accumulated caesium 137

2007 ◽  
Vol 64 (2) ◽  
pp. 394-404 ◽  
Author(s):  
Aaron D. Spares ◽  
Jeffery M. Reader ◽  
Michael J. W. Stokesbury ◽  
Tom McDermott ◽  
Lubomir Zikovsky ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
North Atlantic ◽  
Tissue Concentration ◽  
Eastern Canada ◽  
Tissue Concentrations ◽  
Atlantic Salmon Salmo Salar ◽  
The North ◽  
The North Atlantic ◽  
High Concentrations

AbstractSpares, A.D., Reader, J.M., Stokesbury, M.J.W., McDermott, T., Zikovsky, L., Avery, T.S., and Dadswell, M.J. 2007. Inferring marine distribution of Canadian and Irish Atlantic salmon (Salmo salar L.) in the North Atlantic from tissue concentrations of bio-accumulated caesium 137. – ICES Journal of Marine Science, 64: 394–404. Atlantic salmon returning from marine migrations to eastern Canada and western Ireland during 2002 and 2003 were analysed for tissue concentrations of bio-accumulated caesium 137 (137Cs). Salmon from Canadian and Irish waters demonstrated concentrations (0.20 ± 0.14 Bq kg−1 and 0.19 ± 0.09 Bq kg−1, mean ± s.d., respectively) suggesting similar oceanic feeding distributions during migration. Canadian aquaculture escapees had a similar mean tissue concentration (0.28 ± 0.22 Bq kg−1), suggesting migration with wild salmon. However, significantly higher concentrations in 1-sea-winter (1SW) escapees (0.43 ± 0.25 Bq kg−1) may alternatively suggest feeding within local estuaries. High concentrations in some Canadian 1SW salmon indicated trans-Atlantic migration. Low concentrations of Canadian multi-sea-winter (MSW) salmon suggested a feeding distribution in the Labrador and Irminger Seas before homeward migration, because those regions have the lowest surface water 137Cs levels. Estimates of wild Canadian and Irish salmon feeding east of the Faroes (∼8°W) were 14.2% and 10.0% (1SW, 24.7% and 11.5%; MSW, 2.9% and 0.0%), respectively. We propose that most anadromous North Atlantic salmon utilize the North Atlantic Gyre for marine migration and should be classified as a single trans-Atlantic straddling stock.

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