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Deep-sea meiofaunal communities in the south-eastern Levantine basin and their shaping factors -- morphological-taxonomy-free metabarcoding approach
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  • Zoya Harbuzov,
  • Valeria Farberova,
  • Moshe Tom,
  • Hadas Lubinevsky
Zoya Harbuzov
IOLR

Corresponding Author:[email protected]

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Valeria Farberova
IOLR
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Moshe Tom
IOLR
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Hadas Lubinevsky
IOLR
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Abstract

The meiofaunal communities of the south-eastern Levantine basin deep sea (54-1418m) were characterized for the first time. Two transects were sampled and sliced down to the 17cm sub-bottom horizon. Oxygen, hydrogen sulfide and methane concentrations in the pore water, grain size spectrum, protein and carbohydrate levels in the sediment and meiofaunal abundance were evaluated in each site across sub-bottom horizons. Amplicon Sequence Variants (ASV) composition and diversity indices were evaluated for most sediment slices in the Northern Haifa transect using metabarcoding. Methodologically, a morphological-taxonomy-free molecular identification was adopted, applying a 18S-V4 DNA barcode. The metabarcoding reference library was based on sequences emerged only from the variety of meiofaunal barcodes from local samples recognized as such from their GenBank annotations. Sequences for the reference library were selected by the machine learning-based DADA2 software, previously indicated to efficiently erase sequencer-introduced errors and creating roughly species-compatible ASV library. Each ASV was defined to contain <3%-dissimilar barcode sequences and 990 meiofaunal ASVs were totally elucidated. The various meiofaunal communities revealed a pattern typical to a bottom which obtain its organic carbon from the photic zone, namely, decreasing abundance and diversity with bottom depth and across sub-bottom horizons. Community composition was generally site-dependent and sub-bottom community profiles were separately clustered for shallow horizons and deeper ones. The relatively sharply-inclined slope bottom at 400m depth on a crest of a sub-marine canyon was an exception, revealed similar species composition across horizons, high protein concentration and faunal abundance, indicating intensive sediment mixing and lateral food transport.