Abstract
The present study sought to quantitatively characterize the live and dead benthic foraminifera communities of the deep southeastern Levantine basin of the Mediterranean Sea (33.4º–31.7 ºN, 31.3º–34.9 ºE; 100–1900 m water depth) and their relationships to environmental conditions. Box corer samples were collected at 50 sites between June and July 2013. The foraminiferal macrofauna (> 250 µm) were enumerated and identified (76% to the species level). Six live foraminiferal assemblages were identified, inhabiting six biotopes, the shelf margin (SM), two upper continental slopes (UCS1 and UCS2), the lower continental slope (LCS), the eastern bathyal plain (EBP) and the western bathyal plain (WBP). The dead communities were divided into four biotopes, generally compatible with the live ones, excluding the UCS2 and the EBP. The foraminiferal density in the various live biotopes was relatively stable across the studied area, excluding the UCS2 and EBP, unlike the density of the dead shells, which increased with depth. The number of taxa per biotope was estimated by rarefaction curves and compared to the observed numbers, with a decreasing number of live taxa with water depth. The alpha-diversity, which was evaluated in relation to the number of sampled individuals, reached an asymptote in all biotopes, with very low values in the WBP. The within-biotope heterogeneity was evaluated by the average Chao-Sørensen similarity index and by a beta-diversity index (exp(gamma diversity) - exp(alpha diversity)), revealing variable heterogeneities in both assemblages. Water depth, sediment grain size mode, CaCO3 (wt%), and clay fraction (wt%) were jointly but feebly correlated with live faunal composition.
Original language | English |
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Pages (from-to) | 72-83 |
Number of pages | 12 |
Journal | Deep-Sea Research Part I: Oceanographic Research Papers |
Volume | 136 |
DOIs | |
State | Published - Jun 2018 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2018 Elsevier Ltd
Funding
The study was initiated and supported by the Israeli Ministry of Infrastructure, Energy and Water resources (Grant No. 212-06-029 ). Special gratitude goes to Mr. Ilan Nissim, the head of the Environmental Department of the Ministry. The study was also partially supported by the PERSEUS project (EC Contract #287600 ) to B.H. The devotion and assistance of the crew of R/V Shikmona and the research assistants who participated in the sampling cruises and performed the laboratory tasks are highly appreciated, especially Mr. Michael Kitin from the Geological Survey of Israel (GSI) and Ms. Eva Misrahi from IOLR. We thank Ms. Hadar Elyashiv for the grain size analysis, Ms. Galina Faershtein and Mr. Stephen Abrahams, all from the GSI, for various laboratory tasks. We are very grateful to the anonymous reviewers and the associate editor for their very helpful revision that improved considerably the manuscript.
Funders | Funder number |
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Ministry of National Infrastructure, Energy and Water Resources | 212-06-029, 287600 |
Keywords
- Benthic ecology
- Benthic foraminifera
- Deep sea
- Levantine basin
- Mediterranean