west indian ocean
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MAUSAM ◽  
2021 ◽  
Vol 67 (2) ◽  
pp. 423-430
Author(s):  
K. BOODHOO ◽  
M. R. LOLLCHUND ◽  
A. F. DILMAHAMOD

In this paper, we propose the use of the Ensemble Empirical Mode Decomposition (EEMD) method in the analysis of trends in climate data. As compared to existing traditional methods, EEMD is simple, fast and reliable. It works by decomposing the time-series data into intrinsic mode functions until a residual component is obtained which represents the trend in the data. The dataset considered consists of satellite precipitation estimates (SPE) obtained from the Tropical Rainfall Measuring Mission (TRMM) for the tropical South-West Indian Ocean (SWIO) basin recorded during the periods January 1998 to December 2013. The SWIO basin spans from the latitudes 5° S to 35° S and the longitudes 30° E to 70° E and comprises of part of the east coast of Africa and some small island developing states (SIDS) such as Comoros, Madagascar, Mauritius and Reunion Island. The EEMD analysis is carried out for summer, winter and yearly time series of the SPE data. The results from the study are presented in terms of intrinsic mode functions (IMFs) and the trends. The analysis reveals that in summer, there is a tendency to have an increase in the amount of rainfall, whereas in winter, from 1998 to 2004 there has been an initial increase of 0.0022 mm/hr/year and from there onwards till 2013 a decrease of 0.00052 mm/hr/year was noted.  


2021 ◽  
Vol 12 ◽  
Author(s):  
Anisah W. Ghoorah ◽  
Toto Chaplain ◽  
Rakotoarivony Rindra ◽  
Smita Goorah ◽  
Ganessen Chinien ◽  
...  

Precision medicine has brought new hopes for patients around the world with the applications of novel technologies for understanding genetics of complex diseases and their translation into clinical services. Such applications however require a foundation of skills, knowledge and infrastructure to translate genetics for health care. The crucial element is no doubt the availability of genomics data for the target populations, which is seriously lacking for most parts of Africa. We discuss here why it is vital to prioritize genomics data for the South West Indian Ocean region where a mosaic of ethnicities co-exist. The islands of the SWIO, which comprise Madagascar, La Reunion, Mauritius, Seychelles and Comoros, have been the scene for major explorations and trade since the 17th century being on the route to Asia. This part of the world has lived through active passage of slaves from East Africa to Arabia and further. Today’s demography of the islands is a diverse mix of ancestries including European, African and Asian. The extent of admixtures has yet to be resolved. Except for a few studies in Madagascar, there is very little published data on human genetics for these countries. Isolation and small population sizes have likely resulted in reduced genetic variation and possible founder effects. There is a significant prevalence of diabetes, particularly in individuals of Indian descent, while breast and prostate cancers are on the rise. The island of La Reunion is a French overseas territory with a high standard of health care and close ties to Mauritius. Its demography is comparable to that of Mauritius but with a predominantly mixed population and a smaller proportion of people of Indian descent. On the other hand, Madagascar’s African descendants inhabit mostly the lower coastal zones of the West and South regions, while the upper highlands are occupied by peoples of mixed African-Indonesian ancestries. Historical records confirm the Austronesian contribution to the Madagascar genomes. With the rapid progress in genomic medicine, there is a growing demand for sequencing services in the clinical settings to explore the incidence of variants in candidate disease genes and other markers. Genome sequence data has become a priority in order to understand the population sub-structures and to identify specific pathogenic variants among the different groups of inhabitants on the islands. Genomic data is increasingly being used to advise families at risk and propose diagnostic screening measures to enhance the success of therapies. This paper discusses the complexity of the islands’ populations and argues for the needs for genotyping and understanding the genetic factors associated with disease risks. The benefits to patients and improvement in health services through a concerted regional effort are depicted. Some private patients are having recourse to external facilities for molecular profiling with no return of data for research. Evidence of disease variants through sequencing represents a valuable source of medical data that can guide policy decisions at the national level. There are presently no such records for future implementation of strategies for genomic medicine.


2021 ◽  
Vol 8 ◽  
Author(s):  
Maëva Perez ◽  
Jin Sun ◽  
Qinzeng Xu ◽  
Pei-Yuan Qian

To date, 13 biologically active hydrothermal vent (HTV) fields have been described on the West Indian Ocean ridges. Knowledge of benthic communities of these vent ecosystems serves as scientific bases for assessing the resilience of these ecosystems under the global effort to strike an elegant balance between future deep-sea mining and biodiversity conservation. This review aims to summarize our up-to-date knowledge of the benthic community structure and connectivity of these Indian vents and to identify knowledge gaps and key research questions to be prioritized in order to assess the resilience of these communities. The HTVs in the West Indian Ocean are home to many unique invertebrate species such as the remarkable scaly-foot snail. While distinct in composition, the macrofaunal communities of the Indian HTVs share many characteristics with those of other HTVs, including high endemism, strong zonation at the local scale, and a simple food web structure. Furthermore, Indian vent benthic communities are mosaic compositions of Atlantic, Pacific, and Antarctic HTV fauna possibly owning to multiple waves of past colonization. Phylogeographic studies have shed new light into these migratory routes. Current animal connectivity across vent fields appears to be highly influenced by distance and topological barriers. However, contrasting differences in gene flow have been documented across species. Thus, a better understanding of the reproductive biology of the Indian vent animals and the structure of their population at the local scale is crucial for conservation purposes. In addition, increased effort should be given to characterizing the vents’ missing diversity (at both the meio and micro-scale) and elucidating the functional ecology of these vents.


2021 ◽  
Vol 35 (1) ◽  
Author(s):  
Rémy Eudeline

The Anguilliformes of Mayotte (French island of the Comoros Archipelago) remain poorly surveyed and poorly known so far. This paper deals with the diversity of the Order Actinopterygii of the lagoon of Mayotte by combining literature data, my own underwater visual censuses, and records from other divers. Most species were identified by in situ photographs. A total of 47 species were listed in detail with picture plates, including 14 species not previously mentioned for the lagoon of Mayotte. This paper shows that the use of citizen science, by providing pictures of observed species, has enormous potential to improve our understanding of the species community from an insufficiently surveyed region


2021 ◽  
Author(s):  
Rudy van der Elst ◽  
Simon Chater ◽  
Dennis King

Bassas da India is a remote, uninhabited coral atoll in the West Indian Ocean. Its inaccessibility had historically precluded study of its ichthyofauna until a small group of scientists from the Oceanographic Research Institute in South Africa undertook a two-week biodiversity survey in 1991. Since then, the discourse on climate change has taken on a higher relevance, calling for protection and study of biodiversity hotspots such as Bassas da India. The survey recorded 309 fish species, including a number of vulnerable teleosts and elasmobranchs. As the only published information on the biodiversity of this remote small island, it is intended that this dataset will contribute to increased relevance as an ecological baseline for detecting impacts relating to climate change in the South West Indian Ocean. Each species is listed in terms of its individual abundance, IUCN status as well as its museum and photographic record. Comparisons are made with survey results of other small coral islands in the region, notably Europa Island, revealing several distinct differences in fish diversity. There is evidence that giant groupers will replace sharks as apex predators when there is no local exploitation. A total of 86 species were photographed to confirm identity, and a further 84 species were provided to the South African Institute for Aquatic Biodiversity museum in Grahamstown and also to several international species experts.


2021 ◽  
Author(s):  
Rudy van der Elst ◽  
Simon Chater ◽  
Dennis King

Bassas da India is a remote, uninhabited coral atoll in the West Indian Ocean. Its inaccessibility had historically precluded study of its ichthyofauna until a small group of scientists from the Oceanographic Research Institute in South Africa undertook a two-week biodiversity survey in 1991. Since then, the discourse on climate change has taken on a higher relevance, calling for protection and study of biodiversity hotspots such as Bassas da India. The survey recorded 309 fish species, including a number of vulnerable teleosts and elasmobranchs. As the only published information on the biodiversity of this remote small island, it is intended that this dataset will contribute to increased relevance as an ecological baseline for detecting impacts relating to climate change in the South West Indian Ocean. Each species is listed in terms of its individual abundance, IUCN status as well as its museum and photographic record. Comparisons are made with survey results of other small coral islands in the region, notably Europa Island, revealing several distinct differences in fish diversity. There is evidence that giant groupers will replace sharks as apex predators when there is no local exploitation. A total of 86 species were photographed to confirm identity, and a further 84 species were provided to the South African Institute for Aquatic Biodiversity museum in Grahamstown and also to several international species experts.


2021 ◽  
Vol 17 (7) ◽  
pp. e1009714
Author(s):  
Paola E. Campos ◽  
Clara Groot Crego ◽  
Karine Boyer ◽  
Myriam Gaudeul ◽  
Claudia Baider ◽  
...  

Over the past decade, ancient genomics has been used in the study of various pathogens. In this context, herbarium specimens provide a precious source of dated and preserved DNA material, enabling a better understanding of plant disease emergences and pathogen evolutionary history. We report here the first historical genome of a crop bacterial pathogen, Xanthomonas citri pv. citri (Xci), obtained from an infected herbarium specimen dating back to 1937. Comparing the 1937 genome within a large set of modern genomes, we reconstructed their phylogenetic relationships and estimated evolutionary parameters using Bayesian tip-calibration inferences. The arrival of Xci in the South West Indian Ocean islands was dated to the 19th century, probably linked to human migrations following slavery abolishment. We also assessed the metagenomic community of the herbarium specimen, showed its authenticity using DNA damage patterns, and investigated its genomic features including functional SNPs and gene content, with a focus on virulence factors.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11710
Author(s):  
Noa Simon-Blecher ◽  
Avi Jacob ◽  
Oren Levy ◽  
Lior Appelbaum ◽  
Shiran Elbaz-Ifrah ◽  
...  

Barnacles of the genus Chthamalus are commonly encountered rocky intertidal shores. The phylogeography of the different species in the Western Indian Ocean is unclear. Using morphological characteristics as well as the molecular markers mitochondrial cytochrome oxygenase subunit I (COI) and the nuclear sodium-potassium ATPase (NaKA), we identified four clades representing four species in the Western Indian Ocean and its adjacent seas. Among these species, a newly identified species, Chthamalus barilani, which was found in Madagascar, Zanzibar and Tanzania. Chthamalus from the coasts of Tanzania and Zanzibar is identified morphologically as C. malayensis, and clusters with C. malayensis from the Western Pacific and the Indo Malayan regions. C. malayensis is regarded as a group of four genetically differentiated clades representing four cryptic species. The newly identified African clade is genetically different from these clades and the pairwise distances between them justify the conclusion that it is an additional cryptic species of C. malayensis. This type of genetic analyses offers an advantage over morphological characterization and allowed us to reveal that another species, C. barnesi, which is known from the Red Sea, is also distributed in the Arabian Sea and the Persian Gulf. We could also confirm the presence of the South African species C. dentatus in the Mozambique channel. This represents the Northeastern limit of C. dentatus, which is usually distributed along the coast of southern Africa up to the Islands of Cape Verde in West Africa. Altogether, based on a combination of morphology and genetics, we distinct between four clusters of Chthamalus, and designate their distribution in the West Indian Ocean. These distinctions do not agree with the traditional four groups reported previously based merely on morphological data. Furthermore, these findings underline the importance of a combining morphological and genetics tools for constructing barnacle taxonomy.


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