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Correlation of Virgulinella fragilis Grindell & Collen (benthic foraminiferid) with near-anoxia in Aso-kai Lagoon, central Japan


The distribution of Virgulinella fragilis and the hydro-environment of Aso-kai Lagoon, central Japan, were studied to clarify the foraminifer's adaptation to low-oxygen conditions. The hypolimnion of the lagoon is oxygen-poor during much of the year. Two faunas (A and B) are recognized, based on cluster analysis. Cluster A fauna consists of species common in brackish lagoons, such as the genera Trochammina and Ammonia, and occurs in seasonally oxygenated waters. Virgulinella fragilis, the predominant species of Cluster B fauna, dominates the central part of the lagoon. This species can tolerate more severe oxygen deficiencies than the typical brackish foraminifers (e.g., Trochammina spp.) and can adapt to long periods of oxygen-poor conditions in coastal lagoon environments, as well as in pelagic to hemipelagic settings. In order to survive in the near-anoxia of Aso-kai Lagoon, V. fragilis may have adapted to environments in which little reactive iron is available in the sediment, leaving pore-water and bottom-water sulfide available for symbionts, or may utilize sulfur denitrification processes. J. Micropalaeontol. 24(2): 159-167, October 2005.

ISSN: 0262-821X
EISSN: 2041-4978
Serial Title: Journal of Micropalaeontology
Serial Volume: 24, Part 2
Title: Correlation of Virgulinella fragilis Grindell & Collen (benthic foraminiferid) with near-anoxia in Aso-kai Lagoon, central Japan
Affiliation: Shimane University, Research Center for Coastal Lagoon Environments, Matsue, Japan
Pages: 159-167
Published: 200510
Text Language: English
Publisher: British Micropalaeontological Society, London, United Kingdom
References: 17
Accession Number: 2006-083634
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables, sketch maps
N35°31'60" - N35°31'60", E135°10'60" - E135°10'60"
Secondary Affiliation: Japan Agency for Marine-Earth Science and Technology, JPN, JapanKyoto University of Education, JPN, Japan
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 200647
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