Early to Late Maastrichtian environmental changes in the Indian Ocean compared with Tethys and South Atlantic

2017 ◽  
Vol 478 ◽  
pp. 121-138 ◽  
Author(s):  
Paula Mateo ◽  
Gerta Keller ◽  
Jahnavi Punekar ◽  
Jorge E. Spangenberg
Keyword(s):  
Indian Ocean ◽  
Environmental Changes ◽  
South Atlantic ◽  
The Indian Ocean

Port town and its harbors: sedimentary proxies for landscape and seascape reconstruction of the Greco-Roman site of Berenike Trogodytica on the Red Sea coast of Egypt

2018 ◽  
Vol 26 (2) ◽  
pp. 61-92 ◽  
Author(s):  
Anna M. Kotarba-Morley
Keyword(s):  
Indian Ocean ◽  
Red Sea ◽  
Environmental Changes ◽  
Greco Roman ◽  
The Indian Ocean ◽  
Geographical Position ◽  
Red Sea Coast ◽  
Trade And Exchange ◽  
Changing Role ◽  
Sea Coast

Berenike Trog<l>odytica was one of the key harbours on the Red Sea coast during the Ptolemaic and Roman periods and was a major trade and exchange hub connecting the Indian Ocean and the Mediterranean. Berenike’s geographical position was extraordinarily propitious owing partly to its natural harbours, protected against the prevailing northern winds, as well as its location in the vicinity of an ancient viewshed, the large peninsula of Ras Benas. This paper discusses how multifaceted geoarchaeological approaches to the study of ancient ports can contribute to a better understanding of the mechanisms and logistics of maritime trade, as well as fluctuations in its quality and quantity. It also sheds new light on the significance of the effect that local and regional palaeoclimatic, landscape, seascape and environmental changes had on the development and decline of the port, and its changing role within the Red Sea–Indian Ocean maritime network.

scholarly journals The Role of Interocean Exchanges on Decadal Variations of the Meridional Heat Transport in the South Atlantic

2011 ◽  
Vol 41 (8) ◽  
pp. 1498-1511 ◽  
Author(s):  
Shenfu Dong ◽  
Silvia Garzoli ◽  
Molly Baringer
Keyword(s):  
Indian Ocean ◽  
Heat Transport ◽  
South Atlantic ◽  
Similar Response ◽  
The South ◽  
Meridional Heat Transport ◽  
Interior Region ◽  
The Pacific ◽  
The Indian Ocean

Abstract The interocean exchange of water from the South Atlantic with the Pacific and Indian Oceans is examined using the output from the ocean general circulation model for the Earth Simulator (OFES) during the period 1980–2006. The main objective of this paper is to investigate the role of the interocean exchanges in the variability of the Atlantic meridional overturning circulation (AMOC) and its associated meridional heat transport (MHT) in the South Atlantic. The meridional heat transport from OFES shows a similar response to AMOC variations to that derived from observations: a 1 Sv (1 Sv ≡ 106 m3 s−1) increase in the AMOC strength would cause a 0.054 ± 0.003 PW increase in MHT at approximately 34°S. The main feature in the AMOC and MHT across 34°S is their increasing trends during the period 1980–93. Separating the transports into boundary currents and ocean interior regions indicates that the increase in transport comes from the ocean interior region, suggesting that it is important to monitor the ocean interior region to capture changes in the AMOC and MHT on decadal to longer time scales. The linear increase in the MHT from 1980 to 1993 is due to the increase in advective heat converged into the South Atlantic from the Pacific and Indian Oceans. Of the total increase in the heat convergence, about two-thirds is contributed by the Indian Ocean through the Agulhas Current system, suggesting that the warm-water route from the Indian Ocean plays a more important role in the northward-flowing water in the upper branch of the AMOC at 34°S during the study period.

scholarly journals An Intrinsic Mode of Interannual Variability in the Indian Ocean

2017 ◽  
Vol 47 (3) ◽  
pp. 701-719 ◽  
Author(s):  
Christopher L. Wolfe ◽  
Paola Cessi ◽  
Bruce D. Cornuelle
Keyword(s):  
Indian Ocean ◽  
Interannual Variability ◽  
Ocean Circulation ◽  
Baroclinic Instability ◽  
Ocean Model ◽  
South Atlantic ◽  
Global Ocean ◽  
Leeuwin Current ◽  
The Indian Ocean ◽  
Atmospheric State

AbstractAn intrinsic mode of self-sustained, interannual variability is identified in a coarse-resolution ocean model forced by an annually repeating atmospheric state. The variability has maximum loading in the Indian Ocean, with a significant projection into the South Atlantic Ocean. It is argued that this intrinsic mode is caused by baroclinic instability of the model’s Leeuwin Current, which radiates out to the tropical Indian and South Atlantic Oceans as long Rossby waves at a period of 4 yr. This previously undescribed mode has a remarkably narrowband time series. However, the variability is not synchronized with the annual cycle; the phase of the oscillation varies chaotically on decadal time scales. The presence of this internal mode reduces the predictability of the ocean circulation by obscuring the response to forcing or initial condition perturbations. The signature of this mode can be seen in higher-resolution global ocean models driven by high-frequency atmospheric forcing, but altimeter and assimilation analyses do not show obvious signatures of such a mode, perhaps because of insufficient duration.

Southern by Degrees

2017 ◽  
Author(s):  
Isabel Hofmeyr
Keyword(s):  
Indian Ocean ◽  
South Atlantic ◽  
Literary Representations ◽  
The South ◽  
Anglophone Literature ◽  
Subantarctic Islands ◽  
Imperial Expansion ◽  
The Indian Ocean ◽  
The Antarctic

From the perspective of Anglophone literature, the South Atlantic has been something of a blank—in colonial maritime fiction, a prefatory space leading up to the Cape of Storms or on the journey home, a fast-forward space as the ship hurries to the metropole. This article suggests that one way to fill this blank is to focus on the subantarctic islands of the South Atlantic and the Indian Ocean. This insular world played a key role in the scramble for the Antarctic and reproduces the role of islands in imperial expansion elsewhere. The article examines two contrasting literary representations of these island worlds: H. Rider Haggard’s novel Mary of Marion Isle and Yvette Christiansë’s collection of poetry Imprendehora.

scholarly journals Revisiting remote drivers of the 2014 drought in South-Eastern Brazil

2020 ◽  
Vol 55 (11-12) ◽  
pp. 3197-3211
Author(s):  
Kathrin Finke ◽  
Bernat Jiménez-Esteve ◽  
Andréa S. Taschetto ◽  
Caroline C. Ummenhofer ◽  
Karl Bumke ◽  
...  
Keyword(s):  
Indian Ocean ◽  
General Circulation ◽  
Circulation Model ◽  
Tropical Pacific ◽  
South Atlantic ◽  
The South ◽  
South Eastern ◽  
Eastern Brazil ◽  
The Indian Ocean ◽  
Sst Anomalies

Abstract South-Eastern Brazil experienced a devastating drought associated with significant agricultural losses in austral summer 2014. The drought was linked to the development of a quasi-stationary anticyclone in the South Atlantic in early 2014 that affected local precipitation patterns over South-East Brazil. Previous studies have suggested that the unusual blocking was triggered by tropical Pacific sea surface temperature (SST) anomalies and, more recently, by convection over the Indian Ocean related to the Madden–Julian Oscillation. Further investigation of the proposed teleconnections appears crucial for anticipating future economic impacts. In this study, we use numerical experiments with an idealized atmospheric general circulation model forced with the observed 2013/2014 SST anomalies in different ocean basins to understand the dominant mechanism that initiated the 2014 South Atlantic anticyclonic anomaly. We show that a forcing with global 2013/2014 SST anomalies enhances the chance for the occurrence of positive geopotential height anomalies in the South Atlantic. However, further sensitivity experiments with SST forcings in separate ocean basins suggest that neither the Indian Ocean nor tropical Pacific SST anomalies alone have contributed significantly to the anomalous atmospheric circulation that led to the 2014 South-East Brazil drought. The model study rather points to an important role of remote forcing from the South Pacific, local South Atlantic SSTs, and internal atmospheric variability in driving the persistent blocking over the South Atlantic.

The rare deep-living hyperiid amphipod Megalanceoloides remipes (Barnard, 1932): complementary description and symbiosis

Zootaxa ◽  
2016 ◽  
Vol 4178 (1) ◽  
pp. 138 ◽  
Author(s):  
REBECA GASCA ◽  
STEVEN H.D. HADDOCK
Keyword(s):  
Pacific Ocean ◽  
Indian Ocean ◽  
Gulf Of California ◽  
South Atlantic ◽  
Symbiotic Association ◽  
The Pacific ◽  
The Indian Ocean ◽  
The Pacific Ocean ◽  
In Situ Observations

A female ovigerous specimen of the rare deep-living hyperiid Megalanceoloides remipes (Barnard, 1932) was collected with a remotely operated submersible (ROV) at a depth of 2,094 m in the Farallon Basin, Gulf of California. The specimen was found to be symbiotically associated with the siphonophore Apolemia sp. Eschscholtz, 1829. Hitherto, this species was known only from two other specimens, one from the South Atlantic and another from the Indian Ocean; the present record is the first from the Pacific Ocean. Previous descriptions lacked morphological details of different appendages; these data are provided here. In addition, we present the first data on its symbiotic association from in situ observations. The colors of the hyperiid and of some parts of the Apolemid were very similar, thus supporting the notion that some hyperiids tend to mimic the color of its host. 

scholarly journals DISTRIBUSI FORAMINIFERA BENTIK DI PERAIRAN ACEH

2016 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Nazar Nurdin ◽  
Imelda R. Silalahi
Keyword(s):  
Indian Ocean ◽  
Water Depth ◽  
Surface Sediment ◽  
Benthic Foraminifera ◽  
Environmental Changes ◽  
Sensitive Indicator ◽  
Sediment Samples ◽  
Strong Current ◽  
Reef Environments ◽  
The Indian Ocean

Perairan Aceh termasuk Pulau Weh, Pulau Breuh dan Pulau Penasi merupakan area terluar di sisi barat Kepulauan Indonesia yang menghadap ke Samudera Hindia. Wilayah ini sangat menarik bagi para peneliti terutama setelah kejadian tsunami pada tahun 2004. Tujuan dari penelitian adalah untuk mengetahui distribusi foraminifera sebagai organisme yang sensitif terhadap perubahan lingkungan. Sebanyak 32 contoh sedimen diambil pada kedalaman 7- 170 meter dan terpilih 11 contoh untuk studi foraminifera. Hasil penelitian menunjukkan bahwa ada 45 spesies foraminifera bentik yang sangat berlimpah, terdiri atas 28 spesies anggota Subordo Rotaliina, Miliolina (7 spesies) dan Textulariina (10 spesies). Amphistegina papilosa dijumpai dalam jumlah sangat berlimpah dan tersebar merata yang memberi indikasi kondisi lingkungan terumbu karang baik. Ammonia tepida sangat dominan (47%) di sebelah utara Pulau Weh (S30) dibandingkan dengan spesies lain. Di bagian Timur Pulau Penasi, ditemukan cangkang foraminifera dalam kondisi rusak dalam jumlah berlimpah yang dapat dikaitkan dengan arus kuat di lokasi ini. Kata kunci : foraminifera bentik, distribusi, perairan Aceh The Aceh waters including Weh, Breuh and Penasi islands are the outer parts of northwestern Indonesia that facing the Indian Ocean. This area is interested for many scientists especially after tsunami in 2004. The purpose of this study is to establish the distribution of benthic foraminifera as a sensitive indicator of environmental changes. Thirty two (32) surface sediment samples were collected at the water depth of 7-170 m and eleven samples were selected for foraminiferal study. The results show 45 species of benthic foraminifera very abundantly and consists of 28 species belong to Suborder Rotaliina, Miliolina (7 species) and Textularia (10 species). Amphistegina papilosa is found abundantly and widely distribution that provide an indication of good reef environments. Ammonia tepida is very dominant(47%) in the northern part of Weh island compared with other species. Abnormal shells of foraminifera were found abundantly in the eastern part of Penasi Island that related to strong current in this area. Keywords: benthic foraminifera, distribution, Aceh waters

scholarly journals A ÁFRICA DO SUL, O ATLÂNTICO SUL E A EQUAÇÃO IBAS-BRICS: O ESPAÇO TRANSATLÂNTICO EM TRANSIÇÃO

2013 ◽  
Vol 2 (3) ◽  
pp. 77-106 ◽  
Author(s):  
Francis Kornegay
Keyword(s):  
South Africa ◽  
Developing Countries ◽  
Indian Ocean ◽  
South Atlantic ◽  
Great Powers ◽  
African Continent ◽  
The South ◽  
The Indian Ocean

In a context of increasing South-South cooperation, the members of an important trilateral dialogue forum that represent the emergent powers – IBSA –, have been incorporated into another organization, BRICS. It resulted from an overlap of the Southern developing countries into the domain of the Euro-Asiatic great powers. Bearing in mind that both alliances are centered on the geostrategic space of the Indian Ocean and the South Atlantic, South Africa´s South Atlantic strategic potential in tandem with Brazil is of extreme importance. It is possible to differentiate two steams in the transatlantic ties: the Afro-Latin and the trans-Mediterranean.  It is also relevant to place the role of Angola in the African continent as a possible influence in South Atlantic´s dynamics, given due importance to the Lusophone ties which are represented by CPLP.

Water Mass Transformation and Subduction in the South Atlantic

2005 ◽  
Vol 35 (10) ◽  
pp. 1841-1860 ◽  
Author(s):  
J. Donners ◽  
S. S. Drijfhout ◽  
W. Hazeleger
Keyword(s):  
Surface Water ◽  
Indian Ocean ◽  
Mixed Layer ◽  
Water Mass ◽  
South Atlantic ◽  
Water Masses ◽  
Intermediate Water ◽  
Tropical Atlantic ◽  
The South ◽  
The Indian Ocean

Abstract The transformation of water masses induced by air–sea fluxes in the South Atlantic Ocean is calculated with a global ocean model, Ocean Circulation and Climate Advanced Modeling (OCCAM), and has been compared with several observational datasets. Air–sea interaction supplies buoyancy to the ocean at almost all density levels. The uncertainty of the estimates of water mass transformations is at least 10 Sv (Sv ≡ 106 m3 s−1), largely caused by the uncertainties in heat fluxes. Further analysis of the buoyancy budget of the mixed layer in the OCCAM model shows that diffusion extracts buoyancy from the water column at all densities. In agreement with observations, water mass formation of surface water by air–sea interaction is completely balanced by consumption from diffusion. There is a large interocean exchange with the Indian and Pacific Oceans. Intermediate water is imported from the Pacific, and light surface water is imported from the Indian Ocean. South Atlantic Central Water and denser water masses are exported to the Indian Ocean. The air–sea formation rate is only a qualitative estimate of the sum of subduction and interocean exchange. Subduction generates teleconnections between the South Atlantic and remote areas where these water masses reemerge in the mixed layer. Therefore, the subduction is analyzed with a Lagrangian trajectory analysis. Surface water obducts in the South Atlantic, while all other water masses experience net subduction. The subducted Antarctic Intermediate Water and Subantarctic Mode Water reemerge mainly in the Antarctic Circumpolar Current farther downstream. Lighter waters reemerge in the eastern tropical Atlantic. As a result, the extratropical South Atlantic has a strong link with the tropical Atlantic basin and only a weak direct link with the extratropical North Atlantic. The impact of the South Atlantic on the upper branch of the thermohaline circulation is indirect: water is significantly transformed by air–sea fluxes and mixing in the South Atlantic, but most of it reemerges and subducts again farther downstream.

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