Megafauna of the German exploration licence area for seafloor massive sulphides along the Central and South East Indian Ridge (Indian Ocean)

The growing interest in mineral resources of the deep sea, such as seafloor massive sulphide deposits, has led to an increasing number of exploration licences issued by the International Seabed Authority. In the Indian Ocean, four licence areas exist, resulting in an increasing number of new hydrothermal vent fields and the discovery of new species. Most studies focus on active venting areas including their ecology, but the non-vent megafauna of the Central Indian Ridge and South East Indian Ridge remains poorly known. In the framework of the Indian Ocean Exploration project in the German license area for seafloor massive sulphides, baseline imagery and sampling surveys were conducted yearly during research expeditions from 2013 to 2018, using video sledges and Remotely Operated Vehicles. This is the first report of an imagery collection of megafauna from the southern Central Indian- and South East Indian Ridge, reporting the taxonomic richness and their distribution. A total of 218 taxa were recorded and identified, based on imagery, with additional morphological and molecular confirmed identifications of 20 taxa from 89 sampled specimens. The compiled fauna catalogue is a synthesis of megafauna occurrences aiming at a consistent morphological identification of taxa and showing their regional distribution. The imagery data were collected during multiple research cruises in different exploration clusters of the German licence area, located 500 km north of the Rodriguez Triple Junction along the Central Indian Ridge and 500 km southeast of it along the Southeast Indian Ridge.

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Segmentation of the Central Indian Ridge between 12°12′ S and the Indian Ocean Triple Junction

Marine Geophysical Research ◽

10.1007/bf01982385 ◽

1993 ◽

Vol 15 (4) ◽

pp. 265-282 ◽

Cited By ~ 22

Author(s):

Lindsay M. Parson ◽

Philippe Patriat ◽

Roger C. Searle ◽

Anne R. Briais

Keyword(s):

Indian Ocean ◽

Triple Junction ◽

Central Indian Ridge ◽

The Indian Ocean ◽

Indian Ridge

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A New Species of the Genus Rimicaris (Alvinocarididae: Caridea: Decapoda) from the Active Hydrothermal Vent Field, “Kairei Field,” on the Central Indian Ridge, the Indian Ocean

ZOOLOGICAL SCIENCE ◽

10.2108/zsj.19.1167 ◽

2002 ◽

Vol 19 (10) ◽

pp. 1167-1174 ◽

Cited By ~ 24

Author(s):

Hajime Watabe ◽

Jun Hashimoto

Keyword(s):

New Species ◽

Indian Ocean ◽

Hydrothermal Vent ◽

Central Indian Ridge ◽

The Indian Ocean ◽

Indian Ridge ◽

A New Species ◽

Hydrothermal Vent Field

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Phylogeography of hydrothermal vent stalked barnacles: a new species fills a gap in the Indian Ocean ‘dispersal corridor’ hypothesis

Royal Society Open Science ◽

10.1098/rsos.172408 ◽

2018 ◽

Vol 5 (4) ◽

pp. 172408 ◽

Cited By ~ 12

Author(s):

Hiromi Kayama Watanabe ◽

Chong Chen ◽

Daniel P. Marie ◽

Ken Takai ◽

Katsunori Fujikura ◽

...

Keyword(s):

New Species ◽

Indian Ocean ◽

Hydrothermal Vent ◽

The South ◽

Morphological Variations ◽

East Indian ◽

The Family ◽

The Indian Ocean ◽

Indian Ridge ◽

Dispersal Corridor

Phylogeography of animals provides clues to processes governing their evolution and diversification. The Indian Ocean has been hypothesized as a ‘dispersal corridor’ connecting hydrothermal vent fauna of Atlantic and Pacific oceans. Stalked barnacles of the family Eolepadidae are common associates of deep-sea vents in Southern, Pacific and Indian oceans, and the family is an ideal group for testing this hypothesis. Here, we describe Neolepas marisindica sp. nov. from the Indian Ocean, distinguished from N. zevinae and N. rapanuii by having a tridentoid mandible in which the second tooth lacks small elongated teeth. Morphological variations suggest that environmental differences result in phenotypic plasticity in the capitulum and scales on the peduncle in eolepadids. We suggest that diagnostic characters in Eolepadidae should be based mainly on more reliable arthropodal characters and DNA barcoding, while the plate arrangement should be used carefully with their intraspecific variation in mind. We show morphologically that Neolepas specimens collected from the South West Indian Ridge, the South East Indian Ridge and the Central Indian Ridge belong to the new species. Molecular phylogeny and fossil evidence indicated that Neolepas migrated from the southern Pacific to the Indian Ocean through the Southern Ocean, providing key evidence against the ‘dispersal corridor’ hypothesis. Exploration of the South East Indian Ridge is urgently required to understand vent biogeography in the Indian Ocean.

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Copepoda (Siphonostomatoida: Dirivultidae) from Hydrothermal Vent Fields on the Central Indian Ridge, Indian Ocean

Zootaxa ◽

10.11646/zootaxa.4759.3.1 ◽

2020 ◽

Vol 4759 (3) ◽

pp. 301-337 ◽

Cited By ~ 2

Author(s):

JIMIN LEE ◽

DONGSUNG KIM ◽

IL-HOI KIM

Keyword(s):

Indian Ocean ◽

Deep Water ◽

Hydrothermal Vent ◽

First Record ◽

The Other ◽

Central Indian Ridge ◽

East Pacific ◽

The Family ◽

The Indian Ocean ◽

Indian Ridge

Eight species of copepods belonging to the family Dirivultidae (Siphonostomatoida) are described from deep-water hydrothermal vent fields on the Central Indian Ridge in the Indian Ocean. Aphotopontius limatulus Humes, 1987, previously known only from the East Pacific, is included. The other seven species are new, as follows: Aphotopontius kiost n. sp., A. muricatus n. sp., Benthoxynus constrictus n. sp., Stygiopontius spinifer n. sp., S. horridus n. sp., S. geminus n. sp., and S. quadripaxillifer n. sp. The copepodid I stage of S. horridus n. sp. is also described. This is the first record on copepods living on hydrothermal vent fields in the Indian Ocean.

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Nearest vent, dearest friend: biodiversity of Tiancheng vent field reveals cross-ridge similarities in the Indian Ocean

Royal Society Open Science ◽

10.1098/rsos.200110 ◽

2020 ◽

Vol 7 (3) ◽

pp. 200110 ◽

Cited By ~ 4

Author(s):

Jin Sun ◽

Yadong Zhou ◽

Chong Chen ◽

Yick Hang Kwan ◽

Yanan Sun ◽

...

Keyword(s):

Indian Ocean ◽

Hydrothermal Vents ◽

Southwest Indian Ridge ◽

Central Indian Ridge ◽

Diffuse Flow ◽

Dispersal Barrier ◽

The Indian Ocean ◽

Biological Sampling ◽

Indian Ridge ◽

Key Barrier

Biodiversity of hydrothermal vents in the Indian Ocean, particularly those on the Southwest Indian Ridge (SWIR), are still relatively poorly understood. The Tiancheng field on the SWIR was initially reported with only a low-temperature diffuse flow venting area, but here we report two new active areas, including a chimney emitting high-temperature vent fluids. Biological sampling in these new sites doubled the known megafauna and macrofauna richness reported from Tiancheng. Significantly, we found several iconic species, such as the scaly-foot snail and the first Alviniconcha population on the SWIR. Tiancheng shares a high proportion of taxa with vents on the Central Indian Ridge (CIR) and lacks a number of key taxa that characterize other vents investigated so far on the SWIR. Population genetics of the scaly-foot snail confirmed this, as the Tiancheng population was clustered with populations from the CIR, showing low connectivity with the Longqi field. Unlike the previously examined populations, scales of the Tiancheng scaly-foot snail were coated in zinc sulfide, although this results only from precipitation. The close connection between Tiancheng and CIR vents indicates that the dispersal barrier for vent endemic species is not the Rodriguez Triple Junction as previously suggested but the transformation faults between Tiancheng and Longqi, warranting further studies on deep currents in this area to resolve the key barrier, which has important implications for biological conservation.

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Eocene to recent development of the South-west Indian Ridge, a consequence of the evolution of the Indian Ocean Triple Junction

Geophysical Journal of the Royal Astronomical Society ◽

10.1111/j.1365-246x.1981.tb02686.x ◽

1981 ◽

Vol 64 (3) ◽

pp. 587-604 ◽

Cited By ~ 74

Author(s):

John G. Sclater ◽

Robert L. Fisher ◽

Phillippe Patriat ◽

Christopher Tapscott ◽

Barry Parsons

Keyword(s):

Indian Ocean ◽

Triple Junction ◽

West Indian ◽

The South ◽

South West ◽

The Indian Ocean ◽

Indian Ridge

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Seasonal variations in the Indian Ocean along 110°E. I. Hydrological structure of the upper 500 m

Marine and Freshwater Research ◽

10.1071/mf9690001 ◽

1969 ◽

Vol 20 (1) ◽

pp. 1 ◽

Cited By ~ 62

Author(s):

DJ Rochford

Keyword(s):

Indian Ocean ◽

Surface Waters ◽

Water Masses ◽

Surface Currents ◽

Temperature Changes ◽

East Indian ◽

Hydrological Structure ◽

The Indian Ocean ◽

The Tropics ◽

East Indian Ocean

Tropical and subtropical water masses at surface and subsurface depths were separated by their salinity, temperature, oxygen, and nutrient characteristics. The annual mean depths and latitudinal extent of these water masses were determined. Annual changes in the upper 50 m were generally so small relative to those found in other oceans that advection and mixing must have been less important in their genesis than local climatic changes. There was a barely significant seasonal rhythm in surface phosphate and nitrate, with peak occurrences of each some 6 months apart. At each latitude the permanent thermal discontinuity centred around a particular isotherm varied little in intensity during the year, but rose and fell in accordance with surface currents. The thermocline south of c. 18�S. varied little in depth but greatly in intensity during the summer. The depth of the mixed layer was much less in summer and at all times shallower in the tropics. The depth of this layer was governed more by the accumulation of surface waters by zonal currents and eddies, than by wind stress or convective overturn. Therefore there was little difference from south to north, or month to month, in average nutrient values of this mixed column. The movement of the various surface waters, deduced from salinity and temperature changes during the year, usually agrees with geostrophic currents across 110�E, and ships' observations of surface currents in the south-east Indian Ocean.

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