Depth distribution of benthic foraminifera in the middle and deeper sublittoral to uppermost bathyal zones northwest of Okinawa, Japan


Author : Wan Nurzalia Wan Saelan & Johann HoheneggerPublication : Bulletin of the Geological Society of MalaysiaVolume : 65Page : 77-90Year : 2018


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Bulletin of the Geological Society of Malaysia, Volume 65, June 2018, pp. 77 – 90

Depth distribution of benthic foraminifera in the middle and deeper sublittoral to uppermost bathyal zones northwest of Okinawa, Japan

Wan Nurzalia Wan Saelan1,* & Johann Hohenegger2

1 School of Marine and Environmental Sciences, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Malaysia
2 Department of Palaeontology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
*Corresponding author email address: wannurzalia@umt.edu.my

Abstract: Distribution of dominant species of porcelaneous foraminifera is related to depth in the sublittoral and uppermost bathyal around Okinawa, Japan. Depth is a composite factor that influences physical factors, i.e., temperature, salinity, substrate caused by hydrodynamics and illumination. Depth distribution of optimally preserved porcelaneous tests demonstrate optima in the middle sublittoral, deeper sublittoral and uppermost bathyal zones. Optimal depth distribution of the tests in the middle and deeper sublittoral zones is related to dependence on either coarse sand, medium sand or no dependence on specific substrate type. Optimal depth distribution of the tests in the uppermost bathyal zone is related to dependence on fine and very fine sand. Porcelaneous tests have shown partial agreement between the depth distribution and dependence on substrate type. Life position of the porcelanous foraminifera is influenced by test dominance in percentages of silt and clay. Dominance in the high percentages of silt and clay is reflected in infaunal life position. Dominance in the low percentages of silt and clay is reflected on epifaunal life position. Dominance in medium percentages or no dominance reflects on either epifaunal or infaunal life position. Test dominance in percentages of silt and clay is related to its dependence on substrate type.

Keywords: Optimal tests, porcelaneous foraminifera, depth distribution, substrate dependence, life position