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Meiobenthic assemblage of the grey mangrove (Avicennia marina) along the Saudi Arabian coast of the Red Sea with emphasis on free-living nematodes

Al-Sofyani A., El-Sherbiny M.

Oceanological and Hydrobiological Studies

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2018

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Vol. 47, No. 4

359--375

EN

Spatial variability in the population density of meiofauna and the assemblage of free-living marine nematodes was studied at 20 mangrove sites located along the Saudi Arabian coast of the Red Sea. The total abundance of meiofauna varied between the locations and ranged from 119 to 1380 ind. 10 cm-2. A total of seven main taxa were recorded. Nematodes dominated (64.3%) in all sediment samples. They were followed by harpacticoid copepods (13.2%) and polychaetes (12.9%) with significant differences in their density between the locations surveyed (p < 0.001). The Pearson correlation analysis showed significant positive correlations between the sand fraction and nematodes, harpacticoid copepods and turbellarians. Twenty-five genera of free-living nematodes belonging to 15 families were recorded in the study area. Microlaimidae were the most abundant family, while Xyalidae, Desomodridae and Chromidoridae were the most diverse families. Microlaimus, Halalaimus and Terschellingia were the most frequent genera. ANOSIM values obtained for the distribution of different nematode genera in various habitats showed no significant differences. Feeding types of different nematode genera were also documented and the epistrate feeders along with the deposit feeders were found to be the common feeding types in the present study.

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A brief look at the free-living Nematoda of the oxic/anoxic interface with a new genus record (Trefusia) for the Black Sea

Ürkmez D., Brennan M. L., Sezgin M., Bat L.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 4

539--551

EN

In order to provide the first comparative source of nematofaunal data at the oxic/anoxic interface off the Sinop Peninsula, the southern Black Sea, a survey of meiofauna and nematode fauna was conducted in August 2011 aboard the exploration vessel (E/V) Nautilus with ROV during the Black Sea Expedition NA012. Higher meiofaunal taxa and nematode composition were investigated. Free-living marine nematodes were the most abundant group at each site. A total of 84 species were found, belonging to 23 families. The suboxic zone was dominated by the nematode Trefusia aff. longicauda (42%). This is the first record of the genus Trefusia De Man, 1893 for the Black Sea. Although many factors are likely to influence the changes in the meiofaunal abundance and the composition of nematode assemblages, we suggest that oxygen reduction indeed affected the meiofaunal abundance and the nematode composition, however, a particular preference of several taxa for extreme conditions may be suggested.

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Stranded Zostera marina L. vs wrack fauna community interactions on a Baltic sandy beach (Hel, Poland) : a short-term pilot study. Part II. Driftline effects of succession changes and colonisation of beach fauna

Jędrzejczak M. F.

Oceanologia

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2002

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No. 44 (3)

367-387

EN

This paper evaluates the second part of a three-year field study to investigate the effects of the beach macro- and meiofauna community structure on the decay of stranded wrack on Hel Beach (see Jedrzejczak 2002), focusing on successional changes and the colonisation of wrack by beach fauna. The investigation enabled the associated faunal assemblages to be characterised. Zostera marina tissue was colonised by the supralittoral fauna in two distinct phases. The macrofauna, including the talitrid amphipod Talitrus saltator, adult Diptera and Coleoptera, colonised the wrack within a day, with maximum numbers being recorded after 3 days. Thereafter, their numbers in the samples declined and the meiofauna, consisting of nematodes, oligochaetes, turbellarians and dipteran larvae, became increasingly abundant. After 18 days, the wrack surface was dominated by meiofauna. This faunal succession was not directly related to the degradation of the seagrass tissue, which proceeded linearly throughout the study period. Exclusion of macrofauna from the wrack by the use of < 1 mm mesh litterbags had no appreciable effect on the rate of dry matter loss. Therefore, the major macrofaunal wrack consumers, including T. saltator and Coleoptera, did not affect the rate of seagrass disintegration. The effect of meiofaunal nematodes, oligochaetes, gastrotrichs and turbellarians on wrack breakdown could not be accurately determined. However, the development of the meiofaunal community suggested that changes in the fauna community were linked more closely to successional changes in the chemistry and/or microflora of the beach wrack than to its physical breakdown.