Habitat use of adult male South American fur seals and a preliminary assessment of spatial overlap with trawl fisheries in the South Atlantic

<p>In this contribution, we examine the evolution of the South Atlantic passive margins, based on a new thermal lithosphere-asthenosphere-boundary (LAB) model. Our model is calculated by 1D advection and diffusion with rifting time, crustal thickness and stretching factors as input parameters. The initial lithospheric thickness is defined by isostatic equilibrium with laterally variable crustal and mantle density. We simulate the different rifting stages that caused the opening of the South Atlantic Ocean and pick the LAB as the T=1330&#176; C isotherm. The modelled LAB shows a heterogeneous structure with deeper values at equatorial latitudes, as well as a more variable lithosphere along the southern part. This division reflects different stages of the South Atlantic opening: Initial opening of the southern South Atlantic caused substantial lithospheric thinning, followed by the rather oblique-oriented opening of the equatorial South Atlantic accompanied by severe thinning. Compared to global models, our LAB reflects a higher variability associated with tectonic features on a smaller scale. As an example, we identify anomalously high lithospheric thickness in the South American Santos Basin that is only poorly observed in global LAB models. Comparing the LAB of the conjugate South American and African passive margins in a Gondwana framework reveals a variable lithospheric architecture for the southern parts. Strong differences up to 80 km for selected margin segments correlate with strong gradients in margin width for conjugate pairs. This mutual asymmetry suggests highly asymmetric melting and lithospheric thinning prior to rifting.</p>

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The impact of the subtropical South Atlantic SST on South American precipitation

Annales Geophysicae ◽

10.5194/angeo-26-3457-2008 ◽

2008 ◽

Vol 26 (11) ◽

pp. 3457-3476 ◽

Cited By ~ 24

Author(s):

A. S. Taschetto ◽

I. Wainer

Keyword(s):

South America ◽

Southern Oscillation ◽

South Atlantic ◽

Empirical Orthogonal Functions ◽

Convergence Zone ◽

South American ◽

The South ◽

Inter Tropical Convergence Zone ◽

The Impact ◽

Sst Anomalies

Abstract. The Community Climate Model (CCM3) from the National Center for Atmospheric Research (NCAR) is used to investigate the effect of the South Atlantic sea surface temperature (SST) anomalies on interannual to decadal variability of South American precipitation. Two ensembles composed of multidecadal simulations forced with monthly SST data from the Hadley Centre for the period 1949 to 2001 are analysed. A statistical treatment based on signal-to-noise ratio and Empirical Orthogonal Functions (EOF) is applied to the ensembles in order to reduce the internal variability among the integrations. The ensemble treatment shows a spatial and temporal dependence of reproducibility. High degree of reproducibility is found in the tropics while the extratropics is apparently less reproducible. Austral autumn (MAM) and spring (SON) precipitation appears to be more reproducible over the South America-South Atlantic region than the summer (DJF) and winter (JJA) rainfall. While the Inter-tropical Convergence Zone (ITCZ) region is dominated by external variance, the South Atlantic Convergence Zone (SACZ) over South America is predominantly determined by internal variance, which makes it a difficult phenomenon to predict. Alternatively, the SACZ over western South Atlantic appears to be more sensitive to the subtropical SST anomalies than over the continent. An attempt is made to separate the atmospheric response forced by the South Atlantic SST anomalies from that associated with the El Niño – Southern Oscillation (ENSO). Results show that both the South Atlantic and Pacific SSTs modulate the intensity and position of the SACZ during DJF. Particularly, the subtropical South Atlantic SSTs are more important than ENSO in determining the position of the SACZ over the southeast Brazilian coast during DJF. On the other hand, the ENSO signal seems to influence the intensity of the SACZ not only in DJF but especially its oceanic branch during MAM. Both local and remote influences, however, are confounded by the large internal variance in the region. During MAM and JJA, the South Atlantic SST anomalies affect the magnitude and the meridional displacement of the ITCZ. In JJA, the ENSO has relatively little influence on the interannual variability of the simulated rainfall. During SON, however, the ENSO seems to counteract the effect of the subtropical South Atlantic SST variations on convection over South America.

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At-sea movements and habitat use of adult male Australian fur seals (Arctocephalus pusillus doriferus)

Canadian Journal of Zoology ◽

10.1139/z06-164 ◽

2006 ◽

Vol 84 (12) ◽

pp. 1781-1788 ◽

Cited By ~ 31

Author(s):

Roger Kirkwood ◽

Michael Lynch ◽

Nick Gales ◽

Peter Dann ◽

Michael Sumner

Keyword(s):

Habitat Use ◽

Continental Shelf ◽

Adult Male ◽

Maximum Distance ◽

Commercial Fisheries ◽

Southeastern Australia ◽

Foraging Area ◽

Fur Seals ◽

Water Columns ◽

Foraging Ranges

Foraging by adult male otariids, a demographic component that often interacts with commercial fisheries, are poorly known. To assess movement patterns and habitat use, nine adult male Australian fur seals ( Arctocephalus pusillus doriferus Wood Jones, 1925) from Seal Rocks, in northern Bass Strait, southeastern Australia, were tracked for periods ranging from 66 to 223 d during 1999–2001. Mean ± SD at-sea and on-land durations were 6.9 ± 2.1 d (range 2.3–10.3 d, n = 9 seals) and 2.4 ± 0.9 d (range 0.8–4.1 d), respectively. All seals foraged almost exclusively in continental shelf waters and mostly (65%–97% of time at sea) in water columns that were between 40 and 100 m deep. Six of nine seals tracked for >30 d spent 64%–98% of their time-at-sea foraging at distances <200 km from Seal Rocks, although the maximum distance achieved from the colony was 1208 km. The seals’ foraging ranges overlapped with the ranges of operation of virtually all fin-fish fisheries in southeastern Australia, but fisheries overlap was low in the most frequented foraging area of central-western Bass Strait.

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South Atlantic Surface Boundary Current System during the Last Millennium in the CESM-LME: The Medieval Climate Anomaly and Little Ice Age

Geosciences ◽

10.3390/geosciences9070299 ◽

2019 ◽

Vol 9 (7) ◽

pp. 299

Author(s):

Fernanda Marcello ◽

Ilana Wainer ◽

Peter R. Gent ◽

Bette L. Otto-Bliesner ◽

Esther C. Brady

Keyword(s):

Little Ice Age ◽

South Atlantic ◽

Subtropical Gyre ◽

Ice Age ◽

Surface Boundary ◽

South American ◽

Last Millennium ◽

Medieval Climate Anomaly ◽

The South ◽

Gyre Circulation

Interocean waters that are carried northward through South Atlantic surface boundary currents get meridionally split between two large-scale systems when meeting the South American coast at the western subtropical portion of the basin. This distribution of the zonal flow along the coast is investigated during the Last Millennium, when natural forcing was key to establish climate variability. Of particular interest are the changes between the contrasting periods of the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). The investigation is conducted with the simulation results from the Community Earth System Model Last Millennium Ensemble (CESM-LME). It is found that the subtropical South Atlantic circulation pattern differs substantially between these natural climatic extremes, especially at the northern boundary of the subtropical gyre, where the westward-flowing southern branch of the South Equatorial Current (sSEC) bifurcates off the South American coast, originating the equatorward-flowing North Brazil Undercurrent (NBUC) and the poleward Brazil Current (BC). It is shown that during the MCA, a weaker anti-cyclonic subtropical gyre circulation took place (inferred from decreased southern sSEC and BC transports), while the equatorward transport of the Meridional Overturning Circulation return flow was increased (intensified northern sSEC and NBUC). The opposite scenario occurs during the LIA: a more vigorous subtropical gyre circulation with decreased northward transport.

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The South Atlantic dipole and variations in the characteristics of the South American Monsoon in the WCRP-CMIP3 multi-model simulations

Climate Dynamics ◽

10.1007/s00382-010-0836-9 ◽

2010 ◽

Vol 36 (11-12) ◽

pp. 2091-2102 ◽

Cited By ~ 26

Author(s):

Rodrigo J. Bombardi ◽

Leila M. V. Carvalho

Keyword(s):

South Atlantic ◽

South American ◽

The South ◽

Model Simulations ◽

South American Monsoon ◽

South Atlantic Dipole

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Abstract: Calibration of Marine and Non-Marine Cretaceous Biostratigraphic Frameworks on the African Margins of the South Atlantic Ocean and Their Correlation to the South American Margins

AAPG Bulletin ◽

10.1306/1d9bd4a7-172d-11d7-8645000102c1865d ◽

1998 ◽

Vol 82 (1998) ◽

Author(s):

Chen, Y. Y.; Huang, T. C.; McLaughl

Keyword(s):

Atlantic Ocean ◽

South Atlantic ◽

South Atlantic Ocean ◽

South American ◽

The South

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The effects of invasive rainbow trout on habitat use and diel locomotor activity in the South American Creole perch: an experimental approach

Hydrobiologia ◽

10.1007/s10750-016-2792-9 ◽

2016 ◽

Vol 777 (1) ◽

pp. 243-254 ◽

Cited By ~ 5

Author(s):

María Gabriela Otturi ◽

Miguel Ángel Battini ◽

Juan Pablo Barriga

Keyword(s):

Rainbow Trout ◽

Locomotor Activity ◽

Habitat Use ◽

Experimental Approach ◽

South American ◽

The South

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A new species of Arthrobrachus Solier, Arthrobrachus arquatus n. sp. (Coleoptera: Melyridae) from the South American Transition Zone, Argentina

Zootaxa ◽

10.11646/zootaxa.4441.3.7 ◽

2018 ◽

Vol 4441 (3) ◽

pp. 537

Author(s):

PATRICIA M. ESTRADA

Keyword(s):

New Species ◽

Transition Zone ◽

Adult Male ◽

South American ◽

The South ◽

Central Chile ◽

Male And Female ◽

A New Species

A new species of Arthrobrachus Solier, A. arquatus n. sp. from Argentina, is described using external characters of the adult male and female including terminal segments of the abdomen and genitalia. Arthrobrachus arquatus n. sp. is morphologically close to A. tibialis Solier, 1849 from the Central Chile sub region, suggesting a phylogenetic connection. Comments on the possible origin of this relationship are made.

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Fur Seals Return to Gough Island

Oryx ◽

10.1017/s0030605300016744 ◽

1981 ◽

Vol 16 (1) ◽

pp. 46-47 ◽

Cited By ~ 3

Author(s):

W.R.P. Bourne

Keyword(s):

South Atlantic ◽

The South ◽

Tristan Da Cunha ◽

Fur Seals ◽

Gough Island

After a somewhat perilous landing on Gough Island, south of Tristan da Cunha in the South Atlantic, the author was able to confirm the remarkable comeback of the fur seals there, once heavily exploited but now numbering over a hundred thousand.

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