scholarly journals Nitrogen fixation by epiphytic and epibenthic diazotrophs associated with seagrass meadows along the Tanzanian coast, Western Indian Ocean

2009 ◽  
Vol 57 ◽  
pp. 33-42 ◽  
Author(s):  
MI Hamisi ◽  
TJ Lyimo ◽  
MHS Muruke ◽  
B Bergman
Diversity ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 434
Author(s):  
Linda Eggertsen ◽  
Whitney Goodell ◽  
César A. M. M. Cordeiro ◽  
Thiago C. Mendes ◽  
Guilherme O. Longo ◽  
...  

Spatial configuration of habitat types in multihabitat seascapes influence ecological function through links of biotic and abiotic processes. These connections, for example export of organic matter or fishes as mobile links, define ecosystem functionality across broader spatial scales. Herbivory is an important ecological process linked to ecosystem resilience, but it is not clear how herbivory relates to seascape configuration. We studied how herbivory and bioerosion by 3 species of parrotfish were distributed in a multi-habitat tropical seascape in the Western Indian Ocean (WIO). We surveyed the abundance of three species with different life histories—Leptoscarus vaigiensis (seagrass species), Scarus ghobban (juvenile-seagrass/adults-reefs) and Scarus rubroviolaceus (reef species) —in seagrass meadows and on reefs and recorded their selectivity of feeding substrate in the two habitats. Herbivory rates for L. vaigiensis and S. ghobban and bioerosion for S. rubroviolaceus were then modelled using bite rates for different size classes and abundance and biomass data along seascape gradients (distance to alternative habitat types such as land, mangrove and seagrass). Bioerosion by S. rubroviolaceus was greatest on reefs far from seagrass meadows, while herbivory rates by S. ghobban on reefs displayed the opposite pattern. Herbivory in seagrass meadows was greatest in meadows close to shore, where L. vaigiensis targeted seagrass leaves and S. ghobban the epiphytes growing on them. Our study shows that ecological functions performed by fish are not equally distributed in the seascape and are influenced by fish life history and the spatial configuration of habitats in the seascape. This has implications for the resilience of the system, in terms of spatial heterogeneity of herbivory and bioerosion and should be considered in marine spatial planning and fisheries management.


Ecosystems ◽  
2017 ◽  
Vol 21 (3) ◽  
pp. 551-566 ◽  
Author(s):  
Martin Gullström ◽  
Liberatus D. Lyimo ◽  
Martin Dahl ◽  
Göran S. Samuelsson ◽  
Maria Eggertsen ◽  
...  

2019 ◽  
Vol 166 (10) ◽  
Author(s):  
Holly J. Stokes ◽  
Jeanne A. Mortimer ◽  
Graeme C. Hays ◽  
Richard K. F. Unsworth ◽  
Jacques-Olivier Laloë ◽  
...  

Abstract Green turtles (Chelonia mydas) are key herbivores of tropical and subtropical neritic habitats and play a major role in structuring seagrass meadows. We present the first detailed assessment of green turtle diet in the Western Indian Ocean using the gut contents of salvaged animals from three atolls in the Republic of Seychelles separated from each other by 400–825 km: Cosmoledo (adults, n = 12), Farquhar (adults, n = 33; immature, n = 1) collected in 1982–1983; and Desroches (immatures, n = 8) in 2016–2018. We report the first comparison of the diets of gravid females (n = 17), males (n = 26) and non-breeding females (n = 2) at sites providing both foraging and breeding habitat. Seagrass (mostly Thalassodendron ciliatum) dominated the diet, accounting for 95% of the mean gut content biomass for males and non-breeding females but only 58% for gravid females, alongside relatively large amounts of substrate (14%) and macroalgae (13%). Satellite tracking of post-nesting green turtles from Chagos Archipelago in 2016 located foraging sites at Farquhar Atoll that coincided with capture locations of 26 of the 33 adult turtles sampled there in 1983. In situ surveys of those sites in 2018 revealed extensive nearly monospecific beds of T. ciliatum. The prominence of seagrass in the diet of green turtles and connectivity between foraging and nesting habitats throughout the region illustrate the need to conserve and monitor seagrass habitats of the Western Indian Ocean especially in the context of changing green turtle population densities.


2020 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Editors of the JIOWS

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.


2012 ◽  
Vol 47 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Loïc Charpy ◽  
Katarzyna A. Palinska ◽  
Raeid M. M. Abed ◽  
Marie José Langlade ◽  
Stjepko Golubic

2021 ◽  
Author(s):  
Christoph A. Rohner ◽  
Roy Bealey ◽  
Bernerd M. Fulanda ◽  
Jason D. Everett ◽  
Anthony J. Richardson ◽  
...  

2019 ◽  
Vol 18 (1) ◽  
pp. 11
Author(s):  
Elena Gadoutsis ◽  
Clare A.K. Daly ◽  
Julie P. Hawkins ◽  
Ryan Daly

2020 ◽  
Vol 33 (2) ◽  
pp. 749-765 ◽  
Author(s):  
Rondrotiana Barimalala ◽  
Ross C. Blamey ◽  
Fabien Desbiolles ◽  
Chris J. C. Reason

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.


1966 ◽  
Vol 9 (01) ◽  
pp. 33-37
Author(s):  
Aidan Southall

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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