Abstract
The Israeli coastline is generally characterized by a broad and shallow continental shelf. Akhziv submarine canyon (ASC), in its northern reach, creates a locally unique marine ecosystem. The present study is the first to investigate the benthic macro-fauna of ASC, in order to assess its importance as a potential productivity 'hotspot' within its ultra-oligotrophic surroundings. Seven research cruises were conducted during 2010-2013, along ASC's two channels and at iso-bathic control sites on the adjacent slope (AS), encompassing 8 sampling stations, at depths of 40-450 m. Bottom samples were collected by a Van Veen Grab, gravity corer and a GOMEX box corer. The infauna (≥500 μm) were counted and identified to the lowest possible taxonomic level. Sediments were analysed for grain size & composition and total organic carbon concentration. Mean benthic macro-faunal abundance (individuals/ 500ml ± SD) was higher inside the canyon (13.0±19.4) compared to the AS (2.9±3.3) (p=0.004), as was estimated true taxon richness (Chao1): 42.2 versus 10, respectively. Sediments' mode grain size was found to be significantly higher in ASC's eastern channel compared to AS (p=0.028), along with sand enrichment of up to 36%. The higher macrofaunal abundance and taxon richness may relate to a more heterogeneous sea bed provided by the higher diversity in grain size existing inside ASC. A relatively rich benthic realm, such as that observed in the ASC, may serve as a refuge for certain species and by hosting a relatively diverse assemblage, stands a better chance of adapting to changing conditions such as climate change.
Original language | English |
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Pages (from-to) | 521-531 |
Number of pages | 11 |
Journal | Mediterranean Marine Science |
Volume | 20 |
Issue number | 3 |
DOIs | |
State | Published - 2019 |
Bibliographical note
Funding Information:We would like to thank the crews of R/V Mediterranean Explorer, and Dr. Philip Nemoy for their generous help during the cruises, and to Amir Yurman and Moshiko Bachar (The Leon Recanati Institute for Maritime Studies) for their assistance with technical dives. Additional thanks to Dr. Nimmer Taha, for his technical assistance in the granulometry analyses, to Dr. Faina Gelman from the Geological Survey of Israel, Jerusalem, for TOC analyses and to Bogi Cesare and Sermin Acik Cinar for their help with mollusk identification. The authors would also like to thank Prof. Ido Izhaki, for his generous help with statistical analysis of the data; and to acknowledge EcoOcean; the Sir Maurice & Lady Hatter Scholarship, the Israeli Ministry of Science and Technology (Grant no. 38) and the Helmsley Trust, for the grants that allowed us to carry out the complicated and expensive deep-sea research.
Publisher Copyright:
© 2019 mediterranean marine science.
Keywords
- Granulometry
- Israeli mediterranean slope
- Nepheloid layer
- Submarine canyon
- Total organic carbon
ASJC Scopus subject areas
- Oceanography
- Environmental Engineering
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science