Savvas Genitsaris

Aristotle University of Thessaloniki | AUTH · Department of Botany

Exhaust Gas Cleaning Systems, i.e., “scrubbers”, have been installed on ships as an alternative to low sulfur maritime fuels. The effluent that open-loop systems discharge is a cocktail of low pH seawater with high concentrations of PAHs, metals and particles, and poses concern to the marine environment. Metazooplankton are the first metazoan respo...

The use of novel high‐throughput sequencing (HTS) technologies to examine the responses of natural multidomain microbial communities to scrubber effluent discharges to the marine environment is still limited. Thus, we applied metabarcoding sequencing targeting the planktonic unicellular eukaryotic and prokaryotic fraction (phytoplankton, bacteriopl...

The ephemeral saline lakes of Cyprus in the Mediterranean, situated in close proximity to each other, demonstrate pronounced seasonal and interannual fluctuations in their environmental conditions. Despite their extreme saline conditions, these lakes support phytoplankton diversity and bloom-forming species. Anthropogenic activities, particularly u...

Allowing for installation of exhaust gas cleaning systems (scrubbers) as an alternative to using a cleaner fuel, to comply with the IMO 2020 Sulphur cap, has been done without appropriate consideration of negative impacts on marine life. The toxic and acidic cocktail of scrubber water may pose a serious threat to marine organisms and ecosystems, wi...

Harnessing the biomass energy potential through biofuel production offers new outlets for a circular economy. In this study an integrated system which combine brewery wastewater treatment using algal-bacterial aggregates instead of activated sludge was developed. The use of algal-bacterial aggregates can eliminate the aeration requirements and sign...

In this work, we focused on the functional characterization of unicellular eukaryotic assemblages that had previously been taxonomically characterized by 18S rRNA gene amplicon sequencing in a eutrophic coastal site with marked plankton blooms. Biological traits of different functional groups were assigned to the retrieved operational taxonomic uni...

In the framework of the European Project "Evaluation, control and mitigation of the environmental impacts of shipping emissions (EMERGE)", a wide spectrum of Greek scientists from several disciplines ranging from atmospheric sciences to marine biology have joined forces in order to assess the impact of the widespread adoption of marine scrubbers by...

Understanding the processes that underlay an ecological disaster represents a major scientific challenge. Here, we investigated phytoplankton and zooplankton community changes before and during a fauna mass kill in a European protected wetland. Evidence on gradual development and collapse of harmful phytoplankton blooms, allowed us to delineate the...

We attempted to mimic aeolian ecosystems to examine how filters posed by regional characteristics can influence the establishment and growth of airborne microcolonizers of a common air source. Using a natural single source of aerosols we applied a combined microscopy and high-throughput sequencing (HTS) approach to examine the diversity, settling a...

Anthropogenic marine eutrophication has been recognized as one of the major threats to aquatic ecosystem health. In recent years, eutrophication phenomena, prompted by global warming and population increase, have stimulated the proliferation of potentially harmful algal taxa resulting in the prevalence of frequent and intense harmful algal blooms (...

Plant-associated beneficial strains inhabiting plants grown under harsh ecosystems can help them cope with abiotic stress factors by positively influencing plant physiology, development, and environmental adaptation. Previously, we isolated a potential plant growth promoting strain (AXSa06) identified as Pseudomonas oryzihabitans, possessing 1-amin...

The aim of the study was to investigate the bacterial community diversity and structure by means of 16S rRNA gene high-throughput amplicon sequencing, in the rhizosphere and phyllosphere of halophytes and drought-tolerant plants in Mediterranean ecosystems with different soil properties. The locations of the sampled plants included alkaline, saline...

In the present integrated monitoring study, the quality of the marine environment of the Thermaic Gulf was appraised by measuring physical, chemical and biological parameters of the seawater and seabed. Water and sediment samples were seasonally collected during sampling campaigns from selected stations located at the inner part of Thermaic Gulf. T...

Plant growth promoting rhizobacteria (PGPR) are able to provide cross-protection against multiple stress factors and facilitate growth of their plant symbionts in many ways. The aim of this study was to isolate and characterize rhizobacterial strains under natural conditions, associated with naturally occurring representatives of wild plant species...

The Special Issue entitled “Biodiversity of Marine Microbes” aimed at highlighting the significance of marine microbes as primary producers, their participation in complex processes and interactions with both the biotic and the abiotic environment, and their important roles in biogeochemical cycles and ecosystem functioning. The issue includes five...

The Thessaloniki Bay is a eutrophic coastal area which has been characterized in recent years by frequent and intense phytoplankton blooms and red tides. The aim of the study was to investigate the underexplored diversity of marine unicellular eukaryotes in four different sampling sites in Thessaloniki Bay during a year of plankton blooms, red tide...

The ancient lakes Mikri Prespa and Megali Prespa are located in SE Europe at the transnational triangle and are globally recognized for their ecological significance. They host hundreds of flora and fauna species, and numerous types of habitat of conservational interest. They also provide a variety of ecosystem services. Over the last few decades,...

We explore how the phyllosphere microbial community responds to a very seasonal environment such as the Mediterranean. For this, we studied the epiphytic bacterial community of a Mediterranean ecosystem in summer and winter, expecting to detect seasonal differences at their maximum. With high-throughput sequencing (HTS), we detected the operational...

Climate change has been altering the ocean environment, affecting as a consequence the biological communities including microorganisms. We performed a mesocosm experiment to test whether biodiversity loss caused by one stressor would influence plankton community sensitivity to a subsequent stressor, as envisioned in Vinebrooke’s multiple stressor c...

We investigated the plankton community composition and abundance in the urban marine environment of Thessaloniki Bay. We collected water samples weekly from March 2017 to February 2018 at the coastal front of Thessaloniki city center and monthly samples from three other inshore sites along the urban front of the bay. During the study period, conspi...

Ready-to-eat (RTE) leafy salad vegetables are considered foods that can be consumed immediately at the point of sale without further treatment. The aim of the study was to investigate the bacterial community composition of RTE salads at the point of consumption and the changes in bacterial diversity and composition associated with different househo...

The use of cyanobacteria in biological wastewater treatment technologies can greatly reduce operation costs by combining wastewater bioremediation and production of lipid suitable as biodiesel feedstock. In this work, an attached growth system was employed to achieve the above-mentioned dual objective using a mixed microbial culture dominated by Le...

Climate change has profound impacts on marine biodiversity and biodiversity changes in turn might affect the community sensitivity to impacts of abiotic changes. We used mesocosm experiments and Next Generation Sequencing to study the response of the natural Baltic and Mediterranean unicellular eukaryotic plankton communities (control and +6°C heat...

Decreasing biodiversity is projected as one of the most consistent effects of warming on marine microbial communities. It is predicted that low biodiversity will consequently influence the community sensitivity to additional environmental alterations. Mesocosms were used to study the response of natural Mediterranean phytoplankton communities (cont...

In this study, the quality of the marine environment of Thermaikos Gulf was appraised by measuring physical, chemical and biological parameters of the water column and the seabed. Water and sediment samples were seasonally collected from three sampling stations located at the inner part of Thermaikos Gulf. Specific physical-chemical characteristics...

A mixed cyanobacterial-mixotrophic algal population, dominated by the filamentous cyanobacterium Leptolyngbya sp. and the microalga Ochromonas (which contributed to the total photosynthetic population with rates of less than 5%), was studied under non-aseptic conditions for its efficiency to remove organic and inorganic compounds from different typ...

Thermaikos Gulf, located in the Northwestern Aegean Sea, is a marine ecosystem of major importance, not only environmentally, but also due to the various socioeconomic activities associated with the area (Krestenitis et al., 2012). The present observational study aims to investigate the quality state of seawater and seabed in the Gulf in summer, au...

The diversity of planktonic eukaryotic microbes was studied at a coastal station of the eastern English Channel (EEC) from March 2011 to July 2015 (77 samples) using high throughput sequencing (454-pyrosequencing and Illumina) of the V2-V3 hypervariable region of the 18S SSU rDNA gene. Similar estimations of OTU relative abundance and taxonomic dis...

Microbes are considered to have a global distribution due to their high dispersal capabilities. However, our knowledge of the way geographically distant microbial communities assemble after dispersal in a new environment is limited. In this study, we examined whether communities would converge because similar taxa would be selected under the same e...

The aim of the present study was the study of the planktonic food web of an artificial pond during the bloom of the haptophyte Chrysochromulina parva. For that purpose, the biodiversity and abundance of the phytoplankton and zooplankton communities from the artificial pond, within the campus of A.U.Th., were analyzed. Ten weekly samplings were carr...

The abundance, biomass and the taxonomic composition of the total airborne bacterial communities in a coastal urban area of Northeastern Mediterranean Sea were examined. In total, 27 air samples were collected across three seasons from a sampling point of approximately 30 m altitude in the center of the city. The abundance and biomass were determin...

Combining wastewater treatment with biodiesel production can greatly reduce the cost of environmentally friendly technologies. In this work wastewaters of high environmental importance originating from raisin and wine industries were employed as substrates for a mixed cyanobacterial/algal cultivation system dominated by the filamentous cyanobacteri...

Phytoplankton cell or colony sizes range from <1 µm to several cm, i.e. 4–5 orders of magnitude in linear dimensions, which is roughly equivalent to the log-size span within terrestrial vegetation. It is commonplace to assume that smaller phytoplankton have an advantage in growth related traits while larger ones are more resistant to losses. Howeve...

The aim of this study was to analyze planktonic protistan assemblages under different environmental pressures at 2 adjacent coastal stations (inshore and offshore; ∼6.4 km apart) in the eastern English Channel (EEC). Samples were collected between March 2012 and June 2013, and analyzed using bioinformatic analysis and tag pyrosequencing of the V2-V...

Global warming has revitalized interest in the relationship between body size and temperature, proposed by Bergmann's rule 150 years ago, one of the oldest manifestations of a 'biogeography of traits'. We review biogeographic evidence, results from clonal cultures and recent micro- and mesocosm experiments with naturally mixed phytoplankton communi...

Mussel biofiltration is a widely used approach for the mitigation of aquaculture water. In this study, we investigated the effect of mussel biofiltration on the communities of particle-associated bacteria and unicellular eukaryotes in a sea bass aquaculture in southern North Sea. We assessed the planktonic community changes before and after biofilt...

Supplementary material

In a literature search, the presence of Haematococcus in phytoplankton communities and its biogeography were investigated. Haematococcus, although showing a wide biogeographical distribution, has been rarely found in phytoplankton communities. Simultaneously, the colonization potential of air-dispersed Haematococcus in ephemeral waters and its inte...

The cyanobacterium Aphanizomenon favaloroi was identified for the first time in Europe in the Mediterranean brackish Lake Vistonis during July–August 2014. It formed a dense bloom (from 16 Â 10 6 to 81 Â 10 6 trichomes L À1), causing a brown colouration of the lake water. When A. favaloroi formed 100% of the total phytoplankton biomass (44 mg L À1)...

The microbial taxonomic composition of the three domains of life in two coastal plankton samples was assessed by random total community metagenomic sequencing and PCR-based rDNA amplicon deep-sequencing in order to compare the resulting diversity and investigate possible limitations and complementarities of each method. The various universal primer...

The spatial and temporal community composition of microzooplankton (dinoflagellates and ciliates) was assessed in the Kerguelen area (Southern Ocean) during the KEOPS2 cruise in early spring (October-November) 2011. This naturally iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of phyto...

The aim of the present study was to exam the diversity of aquatic microorganisms in artificial ponds by determining: the composition, abundance and temporal variations of the phytoplankton and zooplankton community. Water samples were collected during the period October - December 2011, 2013 and 2014, on a weekly basis, from experimental devices in...

Previous microscopy-based studies in the eastern English Channel (EEC) have revealed it to be a productive meso-eutrophic coastal ecosystem, characterized by strong repeating patterns in microplankton succession. The present study examines the seasonal structure of the entire protistan community from March 2011 to July 2013, using tag pyrosequencin...

Microbial eukaryotic community composition was examined by 18S rRNA gene tag pyrosequencing, during the early phase of spring phytoplankton blooms induced by natural iron fertilization, off Kerguelen Island in the Southern Ocean (KEOPS2 cruise). A total of 999 operational taxonomical units (OTUs), affiliated to 30 known high-level taxonomic groups,...

Microbial eukaryotic community composition was examined by 18S rRNA gene tag pyrosequencing, during the early phase of spring phytoplankton blooms induced by natural iron fertilization, off Kerguelen Island in the Southern Ocean (KEOPS2 cruise). A total of 999 operational taxonomical units (OTUs), affiliated to 30 known high-level taxonomic groups,...

The objective of this study was to explore the succession of planktonic unicellular eukaryotes by means of 18S rRNA gene tag pyrosequencing in the eastern English Channel (EEC) during the winter to summer transition. The 59 most representative (>0.1 %, representing altogether 95 % of total reads), unique operational taxonomic units (OTUs) from all...

This study examines the plankton succession in a polluted temporary lake after intermittent dry-out. The initial stage after flooding was heterotrophic (zooplankton/phytoplankton carbon biomass ratio > 1). Phytoplankton species richness increased exponentially within a few months after inundation. The chlorophyte Koliella cf. longiseta was the pion...

Airborne freshwater and marine microeukaryotes in the city of Thessaloniki, situated in Thermaikos Bay, Greece, were examined as sources of colonization of experimental water containers during the period autumn 2007 to spring 2008. The microeukaryote composition of the plankton in the nearby aquatic systems (distance < 1 km) was also examined. Airb...

Published information on airborne algae and cyanobacteria worldwide and the related human health effects is scarce. Since 1844, a total of 353 morphological taxa (genera or species) have been identified in aerobiological studies. However, due to diverse methodologies and different microorganisms targeted in these studies, direct comparisons on the...

The morphological and phylogenetic diversity of the microscopic eukaryotes of the Lake Koronia water column was investigated during a mass kill of birds and fish in August-September 2004. The dominant morphospecies corresponded to the known toxin-producing species Prymnesium parvum, followed by Amoebidium sp., a taxon belonging to the group of para...