A preliminary assessment of coastal vulnerability for Ngazidja Island, Comoros Archipelago, Western Indian Ocean

Abstract In previous studies, an emphasis on the particular vulnerability of small island states to future sea-level rise and the intensity of increasing storm surges has been discussed. This preliminary assessment develops a Coastal Vulnerability Index (CVI) along the 202 km long coastline of Ngazidja Island (formerly Grande Comore, Comoros Archipelago), using fieldwork, remote sensing, and geographic information system tools (GIS). The CVI considers five structural variables: (a) geology, (b) geomorphology, (c) topography, (d) shoreline change, and (e) shoreline exposure). It also considers three physical process variables: (f) relative sea-level rise, (g) significant wave height, and (h) mean tide range). The land-use variable was added in this analysis to highlight the human asset exposure in the surrounding areas. Each variable was ranked based on local physical and hydrodynamic conditions and their vulnerability contribution to sea-level rise. The CVI was computed in 270 sections. According to the vulnerability index, approximately 57.5% of the coastline is under low and moderate vulnerability. High and very-high vulnerabilities refer specifically to beaches and shores with old volcanic lava flows located mainly in the northern, northeastern, and southeastern parts of the island, approximately 42.5% of the coastline. The lowest value of CVI is 9.2 on high, rocky cliffs and the highest value is 160 on beaches. This vulnerability partition along the coastline is consistent with in situ indicators of coastal erosion and flooding. In a sea-level rise context, it is of prime importance to integrate coastal vulnerability maps with planning and sustainable management of the coastal zone.

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Editorial Introduction

The Journal of Indian Ocean World Studies ◽

10.26443/jiows.v4i1.68 ◽

2020 ◽

Vol 4 (1) ◽

pp. 1

Author(s):

Editors of the JIOWS

Keyword(s):

Nineteenth Century ◽

Indian Ocean ◽

Western Indian Ocean ◽

Late Nineteenth Century ◽

Fourth Volume ◽

History Of ◽

The Indian Ocean ◽

Complex Relationships ◽

Indian Ocean World ◽

Shed Light

The editors are proud to present the first issue of the fourth volume of the Journal of Indian Ocean World Studies. This issue contains three articles, by James Francis Warren (Murdoch University), Kelsey McFaul (University of California, Santa Cruz), and Marek Pawelczak (University of Warsaw), respectively. Warren’s and McFaul’s articles take different approaches to the growing body of work that discusses pirates in the Indian Ocean World, past and present. Warren’s article is historical, exploring the life and times of Julano Taupan in the nineteenth-century Philippines. He invites us to question the meaning of the word ‘pirate’ and the several ways in which Taupan’s life has been interpreted by different European colonists and by anti-colonial movements from the mid-nineteenth century to the present day. McFaul’s article, meanwhile, takes a literary approach to discuss the much more recent phenomenon of Somali Piracy, which reached its apex in the last decade. Its contribution is to analyse the works of authors based in the region, challenging paradigms that have mostly been developed from analysis of works written in the West. Finally, Pawelczak’s article is a legal history of British jurisdiction in mid-late nineteenth-century Zanzibar. It examines one of the facets that underpinned European influence in the western Indian Ocean World before the establishment of colonial rule. In sum, this issue uses two key threads to shed light on the complex relationships between European and other Western powers and the Indian Ocean World.

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Factors influencing microbial mat composition, distribution and dinitrogen fixation in three western Indian Ocean coral reefs

European Journal of Phycology ◽

10.1080/09670262.2011.653652 ◽

2012 ◽

Vol 47 (1) ◽

pp. 51-66 ◽

Cited By ~ 17

Author(s):

Loïc Charpy ◽

Katarzyna A. Palinska ◽

Raeid M. M. Abed ◽

Marie José Langlade ◽

Stjepko Golubic

Keyword(s):

Indian Ocean ◽

Coral Reefs ◽

Western Indian Ocean ◽

Dinitrogen Fixation ◽

Microbial Mat ◽

Composition Distribution ◽

Factors Influencing

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Movement ecology of black marlin Istiompax indica in the Western Indian Ocean

Journal of Fish Biology ◽

10.1111/jfb.14809 ◽

2021 ◽

Author(s):

Christoph A. Rohner ◽

Roy Bealey ◽

Bernerd M. Fulanda ◽

Jason D. Everett ◽

Anthony J. Richardson ◽

...

Keyword(s):

Indian Ocean ◽

Movement Ecology ◽

Western Indian Ocean

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Post-bleaching mortality of a remote coral reef community in Seychelles, Western Indian Ocean

Western Indian Ocean Journal of Marine Science ◽

10.4314/wiojms.v18i1.2 ◽

2019 ◽

Vol 18 (1) ◽

pp. 11

Author(s):

Elena Gadoutsis ◽

Clare A.K. Daly ◽

Julie P. Hawkins ◽

Ryan Daly

Keyword(s):

Coral Reef ◽

Indian Ocean ◽

Western Indian Ocean ◽

Coral Reef Community ◽

Reef Community

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Variability in the Mozambique Channel Trough and Impacts on Southeast African Rainfall

Journal of Climate ◽

10.1175/jcli-d-19-0267.1 ◽

2020 ◽

Vol 33 (2) ◽

pp. 749-765 ◽

Cited By ~ 3

Author(s):

Rondrotiana Barimalala ◽

Ross C. Blamey ◽

Fabien Desbiolles ◽

Chris J. C. Reason

Keyword(s):

Indian Ocean ◽

Austral Summer ◽

Western Indian Ocean ◽

Strong Relationship ◽

Ocean Basin ◽

Moist Convection ◽

South Indian Ocean ◽

Mozambique Channel ◽

Mascarene High ◽

South Indian

AbstractThe Mozambique Channel trough (MCT) is a cyclonic region prominent in austral summer in the central and southern Mozambique Channel. It first becomes evident in December with a peak in strength in February when the Mozambique Channel is warmest and the Mascarene high (MH) is located farthest southeast in the Indian Ocean basin. The strength and the timing of the mean MCT are linked to that of the cross-equatorial northeasterly monsoon in the tropical western Indian Ocean, which curves as northwesterlies toward northern Madagascar. The interannual variability in the MCT is associated with moist convection over the Mozambique Channel and is modulated by the location of the warm sea surface temperatures in the south Indian Ocean. Variability of the MCT shows a strong relationship with the equatorial westerlies north of Madagascar and the latitudinal extension of the MH. Summers with strong MCT activity are characterized by a prominent cyclonic circulation over the Mozambique Channel, extending to the midlatitudes. These are favorable for the development of tropical–extratropical cloud bands over the southwestern Indian Ocean and trigger an increase in rainfall over the ocean but a decrease over the southern African mainland. Most years with a weak MCT are associated with strong positive south Indian Ocean subtropical dipole events, during which the subcontinent tends to receive more rainfall whereas Madagascar and northern Mozambique are anomalously dry.

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Benthic respiration and standing stock on two contrasting continental margins in the western Indian Ocean: the Yemen-Somali upwelling region and the margin off Kenya

Deep Sea Research Part II Topical Studies in Oceanography ◽

10.1016/s0967-0645(97)00006-4 ◽

1997 ◽

Vol 44 (6-7) ◽

pp. 1293-1317 ◽

Cited By ~ 17

Author(s):

G.C.A. Duineveld ◽

P.A.W.J. De Wilde ◽

E.M. Berghuis ◽

A. Kok ◽

T. Tahey ◽

...

Keyword(s):

Indian Ocean ◽

Standing Stock ◽

Western Indian Ocean ◽

Continental Margins ◽

Benthic Respiration

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“Research in the Western Indian Ocean Region” Conference’: Preliminary Report and Recommendations

African Studies Review ◽

10.1017/s0002020600038993 ◽

1966 ◽

Vol 9 (01) ◽

pp. 33-37

Author(s):

Aidan Southall

Keyword(s):

Indian Ocean ◽

Cultural Anthropology ◽

Western Indian Ocean ◽

Social Background ◽

Columbia University ◽

Indian Ocean Region ◽

Research Committee ◽

Northwestern University ◽

Ocean Region ◽

Syracuse University

The conference was sponsored by the African Research Committee and was held at the Minnowbrook Conference Center of Syracuse University from October 30 to November 2, 1965. The disciplines represented were social and cultural anthropology, musicology, sociology, social psychology, political science, and history. Participants included Philip Allen (Department of State); Frederick Burke (Syracuse University); Remi Clignet (Northwestern University); L. Gray Cowan (Columbia University); Norma McCloud (Tulane University); John Middleton (Northwestern University); Allen Rawick (Library of Congress); Aidan Southall, Chairman (Syracuse University); and Peter Wilson (Yale University). The conference concentrated its efforts on seeking and sharing a common understanding of the social background of the diverse ocean and island region that includes Madagascar, the Comoros, Mauritius, Réunion, and the Seychelles and on exploring precisely the extent to which linked interdisciplinary and comparative studies would be fruitful. The conference came to a strong and unanimous conclusion that the Western Indian Ocean Region offers the challenging possiblity of a real breakthrough in a number of dissimilar but closely interlocking research interests. The main recommendations of the conference are as follows: 1. That a rather informal clearinghouse should be established which would institute and maintain contact between social scientists interested in the region and keep them up to date on all relevant plans and work in progress. 2. That a careful and detailed application should be drawn up to obtain funds for carrying out a series of well-balanced and integrated studies, attracting graduate students and training them for further work, securing library resources, and forming appropriate ties with interested scholars and academic institutions overseas.

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