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Determination of functional structure of soft-bottom marine macrobenthic communities of the Samsun Shelf Area using biological traits analysis

Van Ayşe, Gümüş Aysun

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 4

473--487

EN

Biological Traits Analysis (BTA) was used to investigate the functional structure of marine macrobenthic communities along the Samsun Shelf Area (SSA). Benthic samples were collected seasonally from five different locations and at four different depths using a Van Veen grab sampler. Macrofaunal communities distributed in the SSA were assessed using 10 biological traits to identify characteristic traits for each depth and location. It was found that variability of benthic ecosystem functions in the SSA was driven by biological traits such as maximum size, living habit, sediment position, feeding mode and type of reproductive behavior. Bivalves, polychaetes and crustaceans of small to medium size, biodepositing, burying themselves in the sediment (burrowers) and feeding in suspension were relatively more abundant at depths of 0–60 m. However, the biomass of Amphiura, Abra, Papillicardium and some polychaetes characterized by medium to large sizes, diffusive mixing, free living and feeding on deposit and subsurface deposit showed higher values at depths below 60 m. In general, it is concluded that the functional structure of the benthic infauna in the SSA has adapted to physical disturbance, and communities distributed in this area consist mainly of taxa resistant to mechanical pressure.

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Morphological and Molecular Diversity of Benthic Cyanobacteria Communities Versus Environmental Conditions in Shallow, High Mountain Water Bodies in Eastern Pamir Mountains (Tajikistan)

Jasser Iwona, Kostrzewska-Szlakowska Iwona, Kwiatowski Jan, Navruzshoev Dovutsho, Suska-Malawska Małgorzata, Khomutovska Nataliia

Polish Journal of Ecology

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2019

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Vol. 67, nr 4

286--304

EN

In mountain desert ecosystems, wetlands around saline and freshwater lakes allow various organisms to thrive and sometimes serve as the only source of drinking water for wild and domestic animals. We present results concerning diversity and structure of cyanobacterial inoculum from Eastern Pamir Mountains' benthic sediments, collected from small water bodies with contrasting salinity, temperature and other chemical parameters. We used morphological identification and molecular NGS techniques based on the amplification of the V3-V4 hypervariable region of 16S rRNA gene. Only a few cyanobacterial taxa have been identified in the preserved samples, while 27 taxa were successfully isolated and identified from the benthic sediments. Metagenomic analysis revealed that the cyanobacterial contribution to benthic bacterial communities was low. Representatives of the order Nostocales dominated in the samples, followed by Synechococcales, while contributions of Oscillatoriales and Chroococcales was much lower. The correlation matrix for the amplicon-based composition of samples clustered together samples of similar salinity and temperature. However, in hierarchical clustering of taxonomic structure of samples, communities with similar structures were not grouped by salinity or temperature. These results suggest that salinity and to some extent temperature, influence the composition of the inoculum, although the structure of the cyanobacterial communities is further shaped by other factors. Our study also demonstrated that the benthic inoculum for cyanobacterial communities contained potentially toxic taxa characteristic of both benthic and planktonic communities.

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Influence of the population density and the amount of food on Chironomus plumosus (L.) and Tubificidae. Laboratory experiments

Kajak Z., Prus P.

Polish Journal of Ecology

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2004

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Vol. 52, nr 1

47-53

EN

The aim of this paper has been to examine experimentally the importance of the density of larvae and of the addition of the food for Chironomus and Tubificidae using selected parameters and indices of their populations. Increase of the density of Chironomus plumosus larvae (0.5-50.0 thousands ind. m^-2) in laboratory experiments resulted in the decrease of emergence of imagos, number of tube apertures (3.5-0.4 apertures ind.^-1), and in the lower rate of tubes building. The addition of the food (powdered dry daphnids or food tablets for aquarial fish) had only slight effect on tube numbers but it decreased clearly the getting out of larvae from tubes (probably due to improved feeding conditions inside tubes). It had also a slight negative effect on the survival of larvae. Numbers and individual growth of Tubificidae were positively dependent on the addition of the food (also in the form of naturally dead Chironomus larvae) and negatively - on the density of Chironomus