scholarly journals The Deep-Water Circulation of the Indian Ocean

Nature ◽  
1935 ◽  
Vol 136 (3450) ◽  
pp. 936-938 ◽  
Author(s):  
A. J. Clowes ◽  
G. E. R. Deacon
Keyword(s):  
Indian Ocean ◽  
Deep Water ◽  
Water Circulation ◽  
The Indian Ocean

Foraminiferal tracers of Indian-Atlantic interocean exchange during the last 600 kyr

2020 ◽  
Author(s):  
José N. Pérez-Asensio ◽  
Kazuyo Tachikawa ◽  
Thibault de Garidel-Thoron ◽  
Laurence Vidal ◽  
Corinne Sonzogni ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Atlantic Ocean ◽  
Deep Water ◽  
Water Circulation ◽  
Warm Water ◽  
Temperate Climate ◽  
Agulhas Current ◽  
Foraminiferal Species ◽  
The Indian Ocean ◽  
Relative Abundances

<p>The Indian-Atlantic interocean exchange (IAIE), occurring through Agulhas current and its leakage around the southern tip of Africa, is one of the return flows of global thermohaline circulation that contributes to the temperate climate in Europe. The IAIE affects the transport of heat and salt to the zone of deep-water formation in the N Atlantic, influencing the variability of Atlantic Meridional Overturning Circulation (AMOC). During the last 600 kyr, significant climatic events took place such as the Mid-Bruhnes event (MBE) (~430 ka) that marks a transition towards more intense interglacial periods.</p><p>The main objective of our study is to assess the impact of climate forcing on the strength of both surface and deep water IAIE during the last 600 kyr. For this purpose, we examined the variability of a group of warm-water planktonic foraminiferal species for tracing surface water circulation. We combined published and unpublished data from 3 cores along an Indian-Atlantic transect: two cores in the Indian Ocean, core MD96-2048 (26°10’S, 34°01’E, 660 m) in the source of the Agulhas current and our study core MD96-2077 (33º10’S, 31º14’E, 3781 m) in the middle of the Agulhas current; and one core in the Atlantic Ocean, core ODP1087 (31°27’S, 15°18’E 1372 m) recording the Agulhas leakage.</p><p>Since <em>Globorotalia menardii</em> and <em>Globorotalia tumida</em> are frequently used to trace Agulhas leakage, their variability in Agulhas current in the Indian Ocean is of our interest. Therefore, we compared the relative abundances of the warm-water planktonic <em>G. menardii</em> and <em>G. tumida</em> species with a group of warm-water planktonic foraminiferal species to record the strength of Agulhas current in core MD96-2077. Our results show that the group of warm-water planktonic species reflects increased Agulhas current strength at glacial terminations coinciding with stronger Agulhas leakage (Atlantic core ODP1087) as observed in previous studies. However, in core MD96-2077, both <em>G. menardii</em> and <em>G. tumida</em> relative abundances increase during interglacial periods. This indicates that production of these species in the Agulhas current source region is unlikely to trace Agulhas leakage in the Atlantic Ocean. The analyses of deep-water circulation proxies (Nd isotopes, benthic O and C stable isotopes) are in progress, and they will allow us to assess the response of deep circulation to changes in Agulhas current and leakage over the last 600 kyr.</p>

Lower Cretaceous Deep-Water Benthic Foraminifera of the Indian Ocean

1998 ◽  
Vol 44 (2) ◽  
pp. 209
Author(s):  
W. A. Berggren ◽  
Anne E. L. Holbourn ◽  
Michael A. Kaminski
Keyword(s):  
Indian Ocean ◽  
Deep Water ◽  
Benthic Foraminifera ◽  
Lower Cretaceous ◽  
The Indian Ocean

Four new species of Anatomidae (Mollusca: Vetigastropoda) from the Indian Ocean (Reunion, Mayotte) and Australia, with notes on a novel radular type for the family

Zoosymposia ◽  
2008 ◽  
Vol 1 ◽  
pp. 247-264 ◽  
Author(s):  
DANIEL L. GEIGER ◽  
TAKENORI SASAKI
Keyword(s):  
New Species ◽  
Indian Ocean ◽  
Deep Water ◽  
New South ◽  
New South Wales ◽  
Central Field ◽  
South Wales ◽  
The Family ◽  
Réunion Island ◽  
The Indian Ocean

Four new species of Anatomidae are described: Anatoma herberti n. sp. with strong axial sculpture on the shoulder and base; A. austrolissa n. sp. with almost smooth sculpture except for axial cords in the adumbilical half of the base; A. boucheti n. sp. with sunken protoconch and selenizone that starts after more than one teleoconch I whorl; and A. fl exidentata n. sp. with a highly modifi ed radula, shared only with A. austrolissa, among known anatomid species. Three of the species are only known from the Indian Ocean, while the more deep-water A. austrolissa is known from Reunion Island and New South Wales, Australia. The radula of A. flexidentata and A. austrolissa is strikingly different from that of other Anatomidae and Vetigastropoda in that it has flexible equally-shaped teeth in the central field and filamentous teeth in the marginal fi eld. Similar radular morphologies are known from Calliostomatidae.

scholarly journals ASPEK BIOLOGI DAN DAERAH PENANGKAPAN CUCUT BOTOL (Squalus sp.) YANG TERTANGKAP DI PERAIRAN SAMUDERA HINDIA

2017 ◽  
Vol 13 (1) ◽  
pp. 35
Author(s):  
Dharmadi Dharmadi ◽  
Fahmi Fahmi
Keyword(s):  
Indian Ocean ◽  
Deep Water ◽  
Fishing Season ◽  
Total Length ◽  
Study Results ◽  
The Indian Ocean ◽  
Dogfish Shark ◽  
Males And Females ◽  
The Relationship ◽  
Fishing Area

Penelitian mengenai keragaman jenis Elasmobranchi dilakukan pada bulan Januari sampai dengan Desember 2002 di pelabuhan-pelabuhan perikanan PPI Cilacap, TPI Palabuhanratu, TPI Kedonganan-Bali, dan PPI Tanjung Luar-Lombok Timur. Cucut botol Squalus sp. merupakan jenis cucut laut dalam yang paling sering dijumpai selama penelitian berlangsung. Hasil penelitian menunjukkan bahwa cucut botol betina lebih sering tertangkap dibandingkan cucut jantan pada setiap waktu pengamatan. Frekuensi panjang cucut botol tertinggi dijumpai pada bulan Juni danAgustus yaitu berkisar antara 62 sampai dengan 68 cm. Nisbah kelamin cucut botol antara jantan betina selama pengamatan adalah 1:1,83. Hubungan antara panjang total tubuh dan panjang klasper cenderung linier dengan nilai R2=0,634326. Puncak musim penangkapan cucut botol terjadi sekitar bulan Agustus. Sedangkan daerah penangkapan cucut botol adalah di perairan Samudera Hindia. A study on diversity Elasmobranchi of was conducted using market surveys method from January to December 2002 at several fish landings in southern Indonesia, i.e. the Cilacap, Palabuhanratu, Kedonganan- Bali, and Tanjung Luar-East Lombok landing sites.A deep water shark, Indonesian shortnose spurdog (Squalus sp.), was the most common deep water sharks captured in the area during the study. Results show that females sharks were caught more frequent at every observation than those of males. The most abundant of Indonesian shortnose spurdog was recorded in June and August ranging from 62 to 68 cm in total length. Sex ratio between males and females of Squalus sp. during the study was 1:1.83, and the relationship between total length and claspers length of dogfish shark was linier (R2=0.634326). The peak fishing season of Indonesian spurdog was occurred in August with the fishing area was in the Indian Ocean.

scholarly journals Deep-water observation of scalloped hammerhead Sphyrna lewini in the western Indian Ocean off Tanzania

2015 ◽  
Vol 8 ◽  
Author(s):  
Alec B.M. Moore ◽  
Andrew R. Gates
Keyword(s):  
Indian Ocean ◽  
Deep Water ◽  
Western Indian Ocean ◽  
Hydrocarbon Exploration ◽  
Remotely Operated Vehicle ◽  
Sphyrna Lewini ◽  
Scalloped Hammerhead ◽  
The Indian Ocean ◽  
Common Behaviour

A scalloped hammerheadSphyrna lewiniwas observed opportunistically from a remotely operated vehicle 1 m off the seabed at 1042 m depth, during hydrocarbon exploration activities in the Ruvuma Basin off Tanzania. The observation, which occurred during night hours, is the deepest accurately recorded for this species and the first deep-water record for the Indian Ocean. The record adds support for the occurrence in deep water during night hours being a widespread and possibly common behaviour in this species, and further expands a small but growing literature that meso- and bathypelagic environments may be of greater importance to elasmobranchs previously considered to be primarily epipelagic.

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