Two New and One Rare Species of Bothid Flounders from Saya de Malha Bank, Indian Ocean (Teleostei: Pleuronectiformes)

Copeia ◽  
1990 ◽  
Vol 1990 (4) ◽  
pp. 1011 ◽  
Author(s):  
Kunio Amaoka ◽  
Hisashi Imamura
Keyword(s):  
Indian Ocean ◽  
Rare Species ◽  
Saya De Malha Bank

scholarly journals Assembly Processes and Co-occurrence Patterns of Abundant and Rare Bacterial Community in the Eastern Indian Ocean

2021 ◽  
Vol 12 ◽  
Author(s):  
Liuyang Li ◽  
Laxman Pujari ◽  
Chao Wu ◽  
Danyue Huang ◽  
Yuqiu Wei ◽  
...  
Keyword(s):  
Microbial Community ◽  
Indian Ocean ◽  
Bacterial Community ◽  
Variable Selection ◽  
Rare Species ◽  
Abundant Species ◽  
Community Diversity ◽  
Eastern Indian Ocean ◽  
Rare Taxa ◽  
Deterministic Processes

Microbial communities are composed of many rare species and a few abundant species. Considering the disproportionate importance of rare species for ecosystem functioning, it is important to understand the mechanisms structuring the rare and abundant components of a diverse community in response to environmental changes. Here, we used a 16S ribosomal RNA gene sequencing approach to investigate the bacterial community diversity in the Eastern Indian Ocean (EIO) during the monsoon and intermonsoon. We employed a phylogenetic null model and network analysis to evaluate the assembly processes and co-occurrence pattern of the microbial community. We found that higher bacterial diversity was detected in the intermonsoon with high temperature and low Chlorophyll a concentrations and N/P ratios. The balance between ecological deterministic processes and stochastic processes varied with seasons in the EIO. Meanwhile, conditionally rare taxa (CRT) were more likely modulated by variable selection processes than always rare taxa (ART) and abundant taxa (AT) (CRT > ART > AT). By linking assembly process and species co-occurrence, we demonstrated that the microbial co-occurrence associations tended to be higher when deterministic processes (mainly variable selection) were weaker. This negative trend was observed in rare species rather than abundant species. The linkage could enhance our understanding of the underlying mechanisms underpinning the generation and maintenance of microbial community diversity.

scholarly journals Current and sea level control the demise of shallow carbonate production on a tropical bank (Saya de Malha Bank, Indian Ocean)

Geology ◽  
2021 ◽  
Author(s):  
Christian Betzler ◽  
Sebastian Lindhorst ◽  
Thomas Lüdmann ◽  
John J. Reijmer ◽  
Juan-Carlos Braga ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Coral Growth ◽  
Carbonate Platforms ◽  
The South ◽  
South Equatorial Current ◽  
Carbonate Production ◽  
Equatorial Current ◽  
Saya De Malha Bank ◽  
And Sea Level

Carbonate platforms are built mainly by corals living in shallow light-saturated tropical waters. The Saya de Malha Bank (Indian Ocean), one of the world’s largest carbonate platforms, lies in the path of the South Equatorial Current. Its reefs do not reach sea level, and all carbonate production is mesophotic to oligophotic. New geological and oceanographic data unravel the evolution and environment of the bank, elucidating the factors determining this exceptional state. There are no nutrient-related limitations for coral growth. A switch from a rimmed atoll to a current-exposed system with only mesophotic coral growth is proposed to have followed the South Equatorial Current development during the late Neogene. Combined current activity and sea-level fluctuations are likely controlling factors of modern platform configuration.

A discussion concerning the floor of the northwest Indian Ocean - Preliminary results of the 1964 cruise of R. V. Chain to the Indian Ocean

1966 ◽  
Vol 259 (1099) ◽  
pp. 218-226 ◽  
Keyword(s):  
Indian Ocean ◽  
Woods Hole Oceanographic Institution ◽  
Flow Measurements ◽  
Submarine Ridge ◽  
Northern Portion ◽  
Geophysical Investigations ◽  
The Indian Ocean ◽  
Saya De Malha Bank ◽  
Southern Section ◽  
Abyssal Hills

Geophysical investigations of the northern Somali Basin and the Seychelles-Mauritius Ridge conducted aboard R.V. Chain of the Woods Hole Oceanographic Institution are described and some results presented. Gravitational and total magnetic fields and bathymetry were measured continuously, and continuous seismic reflexion profiles were recorded over a major portion of the track. Cores, dredge samples, heat flow measurements, and underwater photographs were also obtained. It is considered that the northern portion of the Somali Basin is a deep sedimentary basin partially enclosed to the east by a submarine ridge from which alkaline gabbro has been dredged and to the south by partially buried abyssal hills. On the evidence from seven crossings of the Seychelles-Mauritius Ridge, it is proposed that the Ridge comprises two sections. The northern section, composed of nearly horizontally stratified rocks, extends from near the northern part of Saya de Malha Bank to the Seychelles Platform. The southern section is a linear, probably volcanic ridge that extends from north of Mauritius through Saya de Malha Bank, and may continue as a subsurface feature to the northeast. The two sections abut near Saya de Malha Bank, forming a continuous topographic feature.

A comprehensive taxonomic list of brittle stars (Echinodermata: Ophiuroidea) from submarine caves of the Ryukyu Islands, southwestern Japan, with a description of a rare species, Dougaloplus echinatus (Amphiuridae)

Zootaxa ◽  
2019 ◽  
Vol 4571 (1) ◽  
pp. 73 ◽  
Author(s):  
MASANORI OKANISHI ◽  
YOSHIHISA FUJITA
Keyword(s):  
Indian Ocean ◽  
Rare Species ◽  
Southern China ◽  
First Record ◽  
Ryukyu Islands ◽  
Brittle Stars ◽  
The Ryukyu Islands ◽  
Submarine Cave ◽  
Japanese Waters ◽  
Submarine Caves

The ophiuroid species listed were collected by benthic faunal surveys from 2016 to 2018 in submarine caves of the Ryukyu Islands, southwestern Japan. The material includes 20 species from 8 families, Amphiuridae, Ophiocomidae, Ophiodermatidae, Ophiolepididae, Ophioleucidae, Ophiomyxidae, Ophionereididae and Ophiotrichidae. This is the first comprehensive report of submarine cave-dwelling ophiuroids from Japanese waters. Also provided is a redescription of a rare species, Dougaloplus echinatus (Ljungman, 1867), with a detailed description of its ossicle morphology. The species has previously been reported from Brazil, Australia, Eastern Indian Ocean to Southern China, in 11–118 m depth, and this is the first record of D. echinatus from Japanese waters. A brief discussion of the scarcity of submarine cave systems, and the need for their conservation, is provided. 

New record of the smalleye stingray, Dasyatis microps (Myliobatiformes: Dasyatidae), from the western Indian Ocean

Zootaxa ◽  
2008 ◽  
Vol 1734 (1) ◽  
pp. 65 ◽  
Author(s):  
SIMON J. PIERCE ◽  
WILLIAM T. WHITE ◽  
ANDREA D. MARSHALL
Keyword(s):  
Indian Ocean ◽  
Rare Species ◽  
New Record ◽  
Western Indian Ocean ◽  
Large Size ◽  
Continental Shelves ◽  
Extant Species ◽  
First Occurrence

Members of the Dasyatidae (stingrays) range in width from very small (<24 cm, e.g. the dwarf whipray Himantura walga) to very large size (>200 cm, e.g. the smooth stingray Dasyatis brevicaudata) (Last & Compagno, 1999; White & Dharmadi, 2007). The dasyatids are represented worldwide by more than 70 currently recognised extant species which occur in a variety of habitats, e.g. marine, estuarine and freshwater. They are typically demersal on insular and continental shelves, but one species (the pelagic stingray Dasyatis violacea) is pelagic in oceanic waters (Last & Compagno, 1999). In this paper we report the first occurrence of the smalleye stingray Dasyatis microps (Annandale) in the western Indian Ocean and provide information on the fresh colouration of this rare species.

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