The effect of sampling frequency and spatial and temporal variation in the density of fecal indicator bacteria on the assessment of coastal bathing water quality.

The time and location of sampling as well as the number of samples per season can influence a reliable assessment of bathing water quality. In this study, we investigated the spatio-temporal variation of fecal indicator bacteria (FIB) density and the effects of FIB variability and sampling frequency on the assessment of a single sample and the annual and final assessment of coastal bathing water quality. Increasing the number of samples from 10 to 20 per bathing season had a significant impact on bathing water quality assessment at sites where water quality fluctuations had previously been observed, resulting in a change in water quality to a lower category in 36 % of annual and 54 % of final assessments, suggesting that the minimum number of samples per season should be increased at such sites.

Ecology of aerobic anoxygenic phototrophs on a fine-scale taxonomic resolution in Adriatic Sea unravelled by unsupervised neural network.

Background: Aerobic anoxygenic phototrophs are metabolically highly active, diverse and widespread polyphyletic members of bacterioplankton whose photoheterotrophic capabilities shifted the paradigm about simplicity of the microbial food chain. Despite their considerable contribution to the transformation of organic matter in marine environments, relatively little is still known about their community structure and ecology at fine-scale taxonomic resolution. Up to date, there is no comprehensive (i.

Picoplankton diversity in an oligotrophic and high salinity environment in the central Adriatic Sea.

By combining qualitative 16S metabarcoding and quantitative CARD-FISH methods with neural gas analysis, different patterns of the picoplankton community were revealed at finer taxonomic levels in response to changing environmental conditions in the Adriatic Sea. We present the results of a one-year study carried out in an oligotrophic environment where increased salinity was recently observed. We have shown that the initial state of community structure changes according to environmental conditions and is expressed as qualitative and quantitative changes.

How do open coastal fire episodes' impact sea surface microlayer neuston communities?

Human-induced climate change is expected to increase the frequency and severity of vegetation fires. The Mediterranean region is considered particularly prone to fire episodes in summer. It is well known that pyrogenic particles are an important source of external nutrients for the marine environment, especially in oligotrophic areas.

Lineage-Specific Growth Curves Document Large Differences in Response of Individual Groups of Marine Bacteria to the Top-Down and Bottom-Up Controls.

Marine bacterioplankton represent a diverse assembly of species differing largely in their abundance, physiology, metabolic activity, and role in microbial food webs. To analyze their sensitivity to bottom-up and top-down controls, we performed a manipulation experiment where grazers were removed, with or without the addition of phosphate. Using amplicon-reads normalization by internal standard (ARNIS), we reconstructed growth curves for almost 300 individual phylotypes.

Artificial neural network analysis of microbial diversity in the central and southern Adriatic Sea.

Bacteria are an active and diverse component of pelagic communities. The identification of main factors governing microbial diversity and spatial distribution requires advanced mathematical analyses. Here, the bacterial community composition was analysed, along with a depth profile, in the open Adriatic Sea using amplicon sequencing of bacterial 16S rRNA and the Neural gas algorithm.

Changes in the Trophic Pathways within the Microbial Food Web in the Global Warming Scenario: An Experimental Study in the Adriatic Sea.

A recent analysis of the Mediterranean Sea surface temperature showed significant annual warming. Since small picoplankton microorganisms play an important role in all major biogeochemical cycles, fluxes and processes occurring in marine systems (the changes at the base of the food web) as a response to human-induced temperature increase, could be amplified through the trophic chains and could also significantly affect different aspects of the structure and functioning of marine ecosystems. In this study, manipulative laboratory growth/grazing experiments were performed under in situ simulated conditions to study the structural and functional changes within the microbial food web after a 3 °C increase in temperature.

Is TBX agar a suitable medium for monitoring Escherichia coli in bathing water using the membrane filtration method?

The use of a suitable method for the enumeration of indicator microorganisms is of crucial importance for reliable monitoring and assessment of the quality of bathing waters. Among other characteristics, the method should be selective enough and ensure acceptable relative recovery of target microorganisms. This study presents the basic parameters, relative recovery and categorical performance characteristics of Tryptone Bile X-glucuronide (TBX) agar for Escherichia coli (E.