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The spatial distribution of harmful microalgal taxa along the coasts of the Apulia region (Mediterranean Sea) based on results of eight years (2012-2019) of routine monitoring program and a series of sporadic observations is presented. A total number of 69 potentially harmful taxa were found during the study period. Occurrence, abundance and richness of harmful taxa (toxic, potentially toxic and high biomass producers) varied along the Apulian coasts. The occurrence of harmful species was significantly higher where most of anthropogenic pres-sures overlap than only a few or no pressures existed. The physical alteration of coast is the most important pressure determining this pattern. Despite the variety and the abundances of the harmful microalgae, to our knowledge, no human health problems or risks have been ever recorded, nor were full-blown consequences on marine organisms such as fish kills during algal blooms. However, blooms coupled with water discoloration phenomena could become a big issue to tourism and recreational activities that have locally important socio-economic value.

Coastal habitats provide important ecosystem services, such as the maintenance of ecological sustainability, water quality regulation, nutrient recycling, and sandy beaches which are important areas for recreation and tourism. The quality of seawater is generally measured by determining the concentrations ofEscherichia coliand intestinal Enterococci, which might be affected by the persistent populations of these bacteria in sand. Sand might thus be a significant source of pathogen exposure to beachgoers. The quality of coastal recreational waters can also be affected by eutrophication, water discoloration, and harmful algal blooms, which pose additional human health risks. Here, we conducted a monitoring of the beaches quality along the Taranto Gulf by determining the concentrations of fecal indicator organisms, as well as other parameters that are not traditionally measured (physicochemical parameters,Pseudomonas aeruginosa, and harmful microalgae), in shallow seawater and sand sampled from three beaches. The concentrations of bacteria were determined using both standard microbiological methods and the IDEXX system. Our results demonstrate the utility of measuring a greater number of parameters in addition to those conventionally measured, as well as the importance of assessing the health risks posed by the sand matrix. Additional work is needed to develop rapid analytical techniques that could be used to monitor the microbiological parameters of solid matrices.

Atlantification of Arctic ocean is causing a sharp increase in temperature and salinity around Svalbard Islands and in Kongsfjorden. Such phenomenon and the input of sediment-rich glacial meltwater influence salinity, water column turbidity, and light penetration with ecological implications on the microbial features. With the aim to address the temporal variability of the microbial assemblage in relation to environmental variables, a 7-day study was carried out in Kongsfjorden, in late summer 2013. Abiotic (temperature, salinity, nutrients, total suspended matter, particulate inorganic, and organic carbon) and biotic (phyto -, picophyto-, bacterio-, and virioplankton abundance and microbial respiration) parameters were investigated at a station in the inner fjord area, ca. 8.5 km away from the glacier front. Phyto-, picophyto-, and virioplankton showed low abundance. Dinoflagellates and coccolithophorids dominated the phytoplankton community while Synechococcus sp. the picophytoplankton alone, in relation with Atlantic water. Low virus to bacteria ratios were detected, presumably linked to the high sedimentation rates. Interesting variability for picophytoplankton with depth, virioplankton with both time and depth, and respiratory rates with time were found. Moreover, the organic matter turnover was slower on the first sampling day compared to that of the following days. Planktonic abundance depended on the variability of both hydrology (seawater mass inflow) and freshwater runoff from the glacier (relative turbidity degree). Differently, the metabolic rates of respiration appeared to be linked with the particulate carbon pool. Over 1-week study, the diverse microbial dynamics appeared to be conditioned on complex forcing, emphasizing the importance of high-resolution experiment.

Coccoid cyanobacteria produce a great variety of secondary metabolites, which may have useful properties, such as antibacterial, antiviral, anticoagulant or anticancer activities. These cyanobacterial metabolites have high ecological significance, and they could be considered responsible for the widespread occurrence of these microorganisms. Considering the great benefit derived from the identification of competent cyanobacteria for the extraction of bioactive compounds, two strains of picocyanobacteria (coccoid cyanobacteria &lt, 3 µm) (Cyanobium sp. ITAC108 and Synechococcus sp. ITAC107) isolated from the Mediterranean sponge Petrosia ficiformis were analyzed. The biological effects of organic and aqueous extracts from these picocyanobacteria toward the nauplii of Artemia&nbsp, salina, sea urchin embryos and human cancer lines (HeLa cells) were evaluated. Methanolic and aqueous extracts from the two strains strongly inhibited larval development, on the contrary, in ethyl acetate and hexane extracts, the percentage of anomalous embryos was low. Moreover, all the extracts of the two strains inhibited HeLa cell proliferation, but methanol extracts exerted the highest activity. Gas chromatography–mass spectrometry analysis evidenced for the first time the presence of β-N-methylamino-l-alanine and microcystin in these picocyanobacteria. The strong cytotoxic activity observed for aqueous and methanolic extracts of these two cyanobacteria laid the foundation for the production of bioactive compounds of pharmacological interest.

Kongsfjorden (Spitsbergen, Svalbard) is an inlet treated as a model site for studies on the impact of climate change in the Arctic due to its hydrological features. In this research, seven-days monitoring was carried out to evaluate the effects of hydrological variability on phytoplankton biomass and diversity in the late summer period. Temperature, salinity, nutrients, total suspended matter, phytoplankton abundance and biomass were determined for each sample. The thermo-haline properties of the column water seemed to affect phytoplankton communities. Their abundances and biomass were correlated with the amount of the total suspended matter. Moreover, species composition and biomass dramatically changed throughout the study period. Cold-water and Atlantic species were replaced by temperatewarm water dinoflagellates, including harmful species. An increase in phytoplankton biomass as well as the presence of dinoflagellate aggregations, mainly composed of Prorocentrum cf. gracile, were detected. This kind of algal accumulation is a new phenomenon in the Arctic and was probably related to the mobilization of sediment-rich glacial meltwaters. These findings, even if preliminary, suggest the need to study how additional biomass pulses and the increase of harmful species may alter the food web structure and the biogeochemical cycles, leading to major ecosystem changes.

This paper describes the development of multidisciplinary simulation tools based on a system approach, and its contribution to local political debate on sustainable shellfish farming in a Mediterranean coastal site (Mar Piccolo of Taranto, Ionian Sea). Remote sensing images were used for the first time to count mussel culture plants and to validate information provided by stakeholders and farmers. The data obtained were even more important considering the lack of reliable official statistics. Further, a model was developed to simulate exploratory scenarios. In the modelling platform, the ecosystem and individual mussel growth models (built in the frame of the EU Integrated Project SPICOSA, Science and Policy Integration for Coastal System Assessment) are combined with the Mussel Farm Model (MFM). The simulated scenarios suggested that: 1. Farming is unsustainable, because it exceeds the system carrying capacity; 2. Plant overloading is exacerbated by the negative effects of recurrent heatwaves; 3. Sustainable management measures should be applied to obtain individuals of good quality as well as to extend the juveniles sale period and cope with climate crises. The results show that the described tools may help in the design of viable policies based on operational objectives and feasible technical options. Since until now, production trends cannot be determined based on natural and social factors alone, once applied, this tool will allow for a more exemplary production system. It could also become a good practice example towards a more sustainable development of coastal zones.

A first synoptic and trans-domain overview of plankton dynamics was conducted across the aquatic sites belonging to the Italian Long-Term Ecological Research Network (LTER-Italy). Based on published studies, checked and complemented with unpublished information, we investigated phytoplankton and zooplankton annual dynamics and long-term changes across domains: from the large subalpine lakes to mountain lakes and artificial lakes, from lagoons to marine coastal ecosystems. This study permitted identifying common and unique environmental drivers and ecological functional processes controlling seasonal and long-term temporal course. The most relevant patterns of plankton seasonal succession were revealed, showing that the driving factors were nutrient availability, stratification regime, and freshwater inflow. Phytoplankton and mesozooplankton displayed a wide interannual variability at most sites. Unidirectional or linear long-term trends were rarely detected but all sites were impacted across the years by at least one, but in many case several major stressor(s): nutrient inputs, meteo-climatic variability at the local and regional scale, and direct human activities at specific sites. Different climatic and anthropic forcings frequently co-occurred, whereby the responses of plankton communities were the result of this environmental complexity. Overall, the LTER investigations are providing an unparalleled framework of knowledge to evaluate changes in the aquatic pelagic systems and management options.

Planktonic communities hold a relevant role within the EU Marine Strategy Framework Directive (MSFD). In view of reaching the Good Environmental Status of marine ecosystems, within this Directive the phyto- and zooplanktonic communities have received great attention, while Prokaryotes (Bacteria, Archaea, and Cyanobacteria) have been neglected. Indeed, the relevance of microbes (particularly of the faecal pollution indicators) as water quality indicators, the role that microorganisms play within the biogeochemical fluxes and in the whole ecosystem functioning, are all important features that deserve to be focused within the MSFD. The present study aims at reviewing the main issues where prokaryotic variables find useful application as descriptors of environmental status, trying to develop a panel of prokaryotic indicators suitable for the environmental quality assessment. From a survey of scientific literature and on field datasets, prokaryotic abundance and activities (enzymatic hydrolysis, prokaryotic production, and respiratory rates) are here chosen as early warning sentinels to detect changes in environmental quality, using an integrated approach with trophic (chlorophyll-a, particulate and dissolved organic matter) measurements.

Marine cyanobacteria are a source of bioactive natural compounds, with a wide range of biotechnological applications. However, information on sponge-associated cyanobacteria are relatively scarce to date. In this paper, we carried out the morphological and molecular characterization of eight cyanobacterial strains, previously isolated from the Mediterranean sponge Petrosia ficiformis, and evaluated their biological activities on epithelial- and neuron-like cultured cells of human and murine origin. The new analysis allowed maintaining the assignment of three strains (Cyanobium sp., Leptolyngbya ectocarpi, and Synechococcus sp.), while two strains previously identified as Synechococcus sp. and Leptolyngbya sp. were assigned to Pseudanabaena spp. One strain, i.e., ITAC104, and the ITAC101 strain corresponding to Halomicronema metazoicum, shared extremely high sequence identity, practically representing two clones of the same species. Finally, for only one strain, i.e., ITAC105, assignment to a specific genus was not possible. Concerning bioactivity analyses, incubation of cyanobacterial aqueous cell supernatants induced variable responses in cultured cells, depending on cell type, with some of them showing toxic activity on human epithelial-like cells and no toxic effects on human and rat neuron-like cells. Future investigations will allow to better define the bioactive properties of these cyanobacteria strains and to understand if they can be useful for (a) therapeutic purpose(s).

A bloom of putatively non-indigenous species (NIS) Prorocentrum shikokuense was detected for the first time in the Mediterranean Sea at the Brindisi harbor (Southern Adriatic Sea) on September 2016, in the context of EU Marine Strategy Framework Directive monitoring in the ports. This species is usually observed in the East China Sea and Japanese and Korean waters. In the Brindisi harbor this dinoflagellate reached the concentration 105 cell/L and represented from 30 to 50% of the total phytoplankton population. Besides this event, Prorocentrum shikokuense has not been found blooming until today in Mediterranean waters. This study suggests the necessity to improve the monitoring surveys in areas that are known vulnerable systems to alien and invasive species, such as ports.

The Lesina lagoon (southern Adriatic Sea, Mediterranean) is a coastal lagoon located in a highly intensified farming and tourist area. A monthly sampling was carried out in 1998 in five stations, representative of different hydrological features, in order to analyse phytoplankton composition and its relation to environmental parameters. Our results showed high spatial variability of abiotic variables. Phytoplankton abundances and biomass trends showed marked seasonality, with annual peaks occurring in late winter-early spring and summer periods. Phytoplankton blooms were due to the diatom Thalassiosira pseudonana and the dinoflagellate Prorocentrum cordatum. Statistical analyses showed that salinity and nutrients were the main factors affecting phytoplankton abundance and biomass. Phytoplankton dynamics was associated both to seasonality and the hydrodynamic regime of the system. Moreover, chemical-physical data were analysed together with those collected in the same stations in 2007, to compare their dynamics under different hydrological regimes. The two periods corresponded to the closure and opening, respectively, of canals connecting the lagoon to the sea. In general, abiotic variables (salinity, dissolved oxygen, pH, nitrate, phosphate and silicate concentrations) were significantly affected by the hydrodynamic regime. These data could provide a useful basis to complement the knowledge gained through current monitoring within the framework of the European Directives, as well as to implement conservation and management strategies of these transitional waters.

The abundance, biomass and size-structure of planktonic populations, and the microbial metabolic processes were studied in the Sicily Channel, one of the most important spawning areas in the Mediterranean for anchovy (Engraulis encrasicolus), a pelagic species of commercial interest. Results showed that prokaryotes contribute for the 83% of total carbon biomass. Microphytoplankton abundances and biomasses were dominated by autotrophic nanoflagellates and dinoflagellates (36 identified species) and contribute 11% of total biomass. The microzooplanktonic biomass showed its maximum at the surface or subsurface and its contribution was low (4%). In agreement with the general oligotrophy of the investigated area, the study highlights the prevalence of pico-sized fractions within the whole phytoplankton biomass expressed as chlorophyll content, suggesting the importance of picophytoplankton in sustaining the microbial food web. At the same time, the levels of microbial hydrolytic activities are related to productive processes recycling the organic matter and releasing nutrients (P and N), indicating also an active functioning of ecosystem at low trophic levels. Autotrophic production exceeded oxidation by respiration; at the same time, the co-variation of prokaryotic activities and eggs distribution with temperature in summer was observed. The results obtained confirmed that the area acted as a nursery for small fish and both autotrophic and heterotrophic processes supported by microorganisms were in synergy.

The Mar Piccolo is a semi-enclosed basin subject to different natural and anthropogenic stressors. In order to better understand plankton dynamics and preferential carbon pathways within the planktonic trophic web, an integrated approach was adopted for the first time by examining all trophic levels (virioplankton, the heterotrophic and phototrophic fractions of pico-, nano- and microplankton, as well as mesozooplankton). Plankton abundance and biomass were investigated during four surveys in the period 2013–2014. Beside unveiling the dynamics of different plankton groups in the Mar Piccolo, the study revealed that high portion of the plankton carbon (C) pool was constituted by small-sized (

Planktonic picocyanobacteria (PPC) are known to be a minor component of the pelagic phytocoenoses of coastal and brackish waters but recent studies have shown an increase in the biomass of these microorganisms, particularly in environments subject to anthropogenic pollution. PPC can play an important role in the functioning of the food webs and can modulate their metabolism in response to environmental changes. Most of the information available on PPC concerns open waters but this overview seeks to examine the existing literature on the diversity and ecology of these prokaryotes in coastal and brackish environments. Some recent studies have demonstrated the existence of a large number of picocyanobacterial strains, but their structural diversity (taxonomy) is still largely unknown. Genomics is greatly enhancing our knowledge of picocyanobacterial genetic diversity, but without complementary cytomorphological, ecophysiological and biochemical analyses, correct taxonomic classification cannot be achieved. As coastal environments provide a wide range of goods and services, managers need information on environmental quality and how they can preserve it. Together with other planktonic microbes, PPC are potentially useful as sensitive environmental indicators. More research is needed, not only to forecast and manage their harmful effects on coastal environments, but also to provide new insights into the biotechnological use of selected strains, in the framework of the blue economy.

The dinoflagellates of the genus Ostreopsis Schmidt are toxic species involved in the occurrence of massive blooms. These dinoflagellates are known to produce palytoxin and ovatoxins, which are considered amongst the most poisonous phycotoxins in the world. In this work, aqueous and methanolic extracts of one Ostreopsis cf. ovata Ionian strain were tested on the human-derived HeLa cell line, and cytotoxicity, cytoskeletal rearrangement, and apoptosis induction were recorded by morphological and molecular analysis. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test revealed high toxicity for both extracts, which activity was inhibited by ouabain, which suggests the main involvement of palytoxin-like molecules in the observed toxic effects of this strain. Overall, the effects induced by O. cf. ovata on HeLa cells were dependent on the type of adopted extracts, being both toxic, but with the methanolic extract more toxic than the aqueous one and able to induce cell death by apoptosis. This process was evidenced by both phosphatidylserine exposition and upregulation of caspase-3 gene expression. The different effect of the two extracts on cell death is indicative of their different composition and/or activity. Our findings represent the starting step for the characterization of novel bioactive molecules.

In order to reinforce the network of collaborative efforts established in previous years to facilitate the surfacing, reuse and innovative interpretation of relevant existing marine data, on May 19th 2017, a workshop entitled “The Adriatic Ionian Region: energy resource exploration and exploitation and environmental sustainability” disclosed the results of activities carried out by the research action called "oil & gas". The Conference has been held in Taranto (Southern Italy). The action "oil & gas" of the Ritmare Project aimed to provide an independent scientific standpoint on the controversial issue of exploration and exploitation of hydrocarbons in the Italian seas.

Since 1883, the Mar Piccolo of Taranto (Ionian Sea, Mediterranean) has played a dual role as privileged area for shellfish farming and strategic military port. In the early 1900, the basin already showed some serious environmental and production management deficiencies, stressed by the First World War. This historical research, based on the collection of direct, indirect and iconographic sources, provided socioeconomic information about Taranto from 1883 to 1926 and unprecedented data on the most probable catastrophic effects (the sinking of a dreadnought) on the marine environment during the First World War. Moreover, the study demonstrated that the holistic approach followed by the Marine Biology Laboratory's Inspector (Attilio Cerruti) for the management of shellfish farming could be assimilated to current ‘warfare ecology’. He had to face disastrous effects on the environment jeopardising ancient farming activities. He therefore carried out actions to reduce, mitigate, and prevent warfare effects. The analysis of original documents showed that the strategies (scientific studies, application and propagation of best practices; economic evaluation of productions; communication with military and civil authorities and shellfish farmers) adopted by Cerruti ensured shellfish farming survival and its recovery in the post war period. Moreover, Cerruti's warfare ecology approach could be a useful example for the solution of current management and conservation problems related to goods and services of valuable ecosystems highly impacted by human activities (not limited to warfare), such as those affecting the Mar Piccolo of Taranto.

The Western areas of the Adriatic Sea are subjected to inputs of inorganic nutrients and organic matter that can modify the trophic status of the waters and consequently, the microbiological processes involved in the carbon and phosphorus biogeochemical cycles, particularly in shallow coastal environments. To explore this topic, a survey was carried out during the spring of 2003 in a particular hydrodynamic area of the Gulf of Manfredonia, where the potential (P) and real (R) rates of four different microbial exoenzymatic activities (EEA) (alpha [alpha G] and glucosidases [G], leucine aminopeptidase [LAP], and alkaline phosphatase [AP]) as well as the P and R rates of prokaryotic heterotrophic production (PHP), AP as well as the P and R rates of PHP, primary production (PPnet), the prokaryotic and phototrophic stocks and basic hydrological parameters were examined. Three different water masses were found, with a thermohaline front (THF) being detected between the warmer and less saline coastal waters and colder and saltier offshore Adriatic waters. Under the general oligotrophic conditions of the entire Gulf, a decreasing gradient from the coastal toward the offshore areas was detected, with PHP, PPnet, stocks and EEA (alpha G, G, AP) being directly correlated with the temperature and inversely correlated with the salinity, whereas opposite relationships were observed for LAP activity. No enhancement of microbiological activities or stocks was observed at the THF. The use of P or R rates of microbiological activities, which decrease particularly for EEA, could result in discrepancies in interpreting the efficiency of several metabolic processes.

In many coastal areas the abundant proliferation of microalgae producing biotoxins determines the occurrence of Harmful Algal Blooms (HABs). Their presence in temperate waters is well documented and often associated with marine toxin-derived disease. The occurrence and toxicity of three harmful microalgae (Amphidinium carterae, Coolia cfr. monotis and Ostreopsis cfr. ovata) from the northern Ionian Sea (Mediterranean Sea) is hereby reported. The three dinoflagellates were sampled both on macroalgae and water and their morphology and occurrence were compared to those of other Mediterranean sites. The toxicity of the three cultured strains was tested by Artemia salina and hemolysis tests and their effects on the first stages of the sea urchin development was also evaluated. The contemporary presence of the three species inhibited the in vitro sea urchin embryonic development. But this action could be ascribed to the sole Ostreopsis as the addition of the single species to the sea urchins embryos evidenced no effects in presence of Amphidinium or Coolia cells, and an irregular segmentation in presence of Ostreopsis. In particular, this latter species exerted a cytotoxic effect in a dose-dependent manner, with a production of deformed embryos even at very low cell concentration (42 cells mL−1). Nevertheless, when algal cell lysate was added, some effects on the sea urchin development was detected for each dinoflagellate, and also in this case Ostreopsis has proved to be the most toxic species. However, the lysate of Amphidinium and Ostreopsis strongly affects the A. salina nauplii vitality, while the hemolytic activity was very low for Amphidinium and Coolia lysate and very strong for Ostreopsis. Our results highlight the importance to monitoring the presence of these dinoflagellates whose effects may also be reflected on the early life stages of marine organisms, especially those species that are important from both an ecological and economic point of view, as the sea urchins are.

Ostreopsis cfr. ovata toxicity was estimated through acute bioassays using four crustacean species (Artemia franciscana, Tigriopus fulvus, Corophium insidiosum and Sphaeroma serratum). The epiphytic dinoflagellate showed significant toxicity towards all tested crustaceans, which have usually exhibited the highest mortalities with increasing the dinoflagellate cell concentrations. Furthermore, our results evidenced a higher sensitivity of A. franciscana larvae to Ostreopsis, compared with the other species. The results of our bioassays highlighted the usefulness of employing a base-set of different species rather than one derived from a single species, in order to obtain more reliable information on the algal toxicity.

The Vlora Bay is the only internal sea of the Albanian coastline. The site is of paramount interest for Albanian fishing, being a natural nursery for many fish species of economic importance. The composition of the plankton community in the Vlora Bay has been analysed and particular attention devoted to the unicellular eukaryotes by collecting samples from 16 stations during 2 seasonal cruises (May–June 2007, and January 2008), an effort to date never carried out to know the plankton biodiversity of the area. The microzooplankton community was composed of 122 phytoplankton and 105 microzooplankton taxa, of which 58.2% and 25.0%, respectively, were classified as seasonal (they were recorded only in one of the two considered times). Only four categories (all phytoplanktonic, the diatom Navicula sp., “undetermined naked dinoflagellates < 15 µm”, the coccolithophorid Emiliania huxleyi, and the “undetermined phytoflagellates < 10 µm”) were recorded in all the sampling stations (at least in one period)...

The distribution of the prokaryotic biomass (from both abundance and cell volume measurements) and microbial community respiration (by ETS activity) in the main water masses of the Southern Tyrrhenian Sea were studied. The data were collected from surface to the bottom depth (max 3600 m) in July and December 2005. Prokaryotic abundance and microbial respiration were higher in summer than late-autumn and decreased with depth in accordance with the water masses. The opposite was found for the prokaryotic cell volumes that increased with depth and were higher in December. The cell carbon content varied within the water masses and study periods (range 9–34 fg C cell−1) and overestimations and underestimations of biomass there would have been by using the routinely adopted conversion factor (20 fg C cell−1). The depth-integrated respiratory rates resulted comparable in the photic and aphotic layers. In July, 210 and 225 mg C m−2 day−1 in the euphotic and aphotic zones, respectively, were remineralized while in December, 112 and 134 mg C m−2 day−1, respectively, were. Speculations to quantify the carbon flow mediated by microbial community suggested the occurrence of different microbial behavior within the different water masses.

The occurrence and abundance of dinoflagellate cysts were investigated for the first time at an Ionian locality along the south-eastern coast of Sicily, subject to spring–summer harmful algal events. Thirty-four cyst morphotypes were recognized belonging to 24 taxa identified at least at the genus level. Cyst abundance in surface sediments ranged from 43 to 828 cysts g−1 dry weight, with the highest numbers recorded at the most restricted station. Germination experiments allowed confirmation of species identification determined by cyst analysis and provided clonal cultures of Alexandrium minutum and Gymnodinium nolleri, two of the bloom-forming species in the area. This represents the first record of G. nolleri for the Mediterranean Sea.

The response of phytoplankton assemblages to the closure of urban sewage outfalls (USOs) was examined for the Mar Piccolo of Taranto (Mediterranean Sea), a productive semi-enclosed coastal marine ecosystem devoted to shellfish farming. Phytoplankton dynamics were investigated in relation to environmental variables, with a particular emphasis on harmful algal blooms (HABs). Recent analyses evidenced a general reduction of the inorganic nutrient loads, except for nitrates and silicates. Also phytoplankton biomass (chlorophyll a) and abundances were characterized by a decrease of the values, except for the inner area of the basin (second inlet). The phytoplankton composition changed, with nano-sized species, indicators of oligotrophic conditions, becoming dominant over micro-sized species. If the closure of the USOs affected phytoplankton dynamics, however, it did not preserve the Mar Piccolo from HABs and anoxia crises. About 25 harmful species have been detected throughout the years, such as the potentially domoic acid producers Pseudo-nitzschia cf. galaxiae and P seudo-nitzschia cf. multistriata, identified for the first time in these waters. The presence of HABs represents a threat for human health and aquaculture. Urgent initiatives are needed to improve the communication with authorities responsible for environmental protection, economic development, and public health for a sustainable mussel culture in the Mar Piccolo.

Sinking biogenic particles drive respiration in the ocean interior, help to maintain the ocean's strong vertical gradient of inorganic carbon and related studies are important to determine the flow of organic matter along the water column. Sediment trap studies have shown that a low percentage of the surface primary production reaches the bottom. However, organic matter collected by sediment traps does not take into account the entire pool of oxidable organic matter, which includes the dissolved organic matter present in the seawater. The study of microbial respiration rates instead fills this gap, since respiration includes oxidation of both dissolved and particulate organic mater, providing an integrated estimate of the carbon utilization in the sea. In this context, a study on an Arctic fjord (Kongsfyorden, Svalbard) was done in late summer 2013, with the purpose of knowing the variability of microbial remineralization rates in relation to particulate organic matter over short time scales in a coastal station (water depth ~105 m), where a mooring (Mooring Dirigibile Italia, MDI: 78° 54 .859'N; 12° 15. 411' E) is positioned. A high variability of carbon dioxide production rates was recorded during the sampling days and this result was related to several factors. Useful information may be deducted for modelling studies of carbon flux in similar areas.

Sampling cruises were carried out on three coastal stations of the northern Ionian Sea over one year to investigate the effects of environmental factors on phytoplankton and picophytoplankton composition and succession. Larger phytoplankton (micro and nano fractions) was determined by using the Utermöhl settling technique, while picophytoplankton fraction was determined by epifluorescence microscopy. Furthermore, microbiological procedures were applied to investigate cyanobacterial diversity in the studied area. Results suggested that the most striking feature of phytoplankton communities was the high spatial variability in terms of abundance and biomass, which showed specific coastal Mediterranean values. Undetermined phytoflagellates and diatoms were the dominant groups of the Utermöhl fraction of phytoplankton, while round to rod-shaped small sized cyanobacteria represented the picophytoplankton fraction. Our data suggested that in the northern Ionian Sea the phytoplankton development was related to phosphorus availability and to ‘nitrogen-rich’ waters. Also the picophytoplankton seasonal trend was significantly correlated to N-compounds as well as to water temperature.In addition to the typical picoplanktonic Synechococcus, the culture techniques allowed us to isolate and identify cyanobacteria belonging to the pleurocapsalean genus Stanieria and the oscillatoriacean genera Geitlerinema, Leiblenia, Leptolyngbya, Oscillatoria, Pseudanabaena and Spirulina. These species represent a minor fraction of the total cyanobacterial community in terms of biomass, but their importance is related to their contribution to the phytoplankton diversity.

This investigation included a 2-year monitoring program aimed at assessing the abundance and distribution of harmful marine phytoplankton along the Southern Adriatic coast of Italy. Monthly sampling was conducted from April 1995 to March 1997 at four sampling stations along four transects, to determine the temporal and spatial presence/abundance of the potentially toxic Pseudonitzschia species. The study focussed on the most abundant taxa Pseudo-nitzschia calliantha and Pseudo-nitzschia delicatissima, the identities of which were confirmed by TEM on cleaned net material. The distribution patterns of these potential Amnesic Shellfish Poisoning (ASP) toxin producers were statistically analysed by Generalised Linear Model ANalysis Of VAriance, Principal Component Analysis (GLM ANOVA, PCA) and Spearman’s correlation analysis in order to address relationships between environmental variable and population dynamics. Abundances displayed horizontal and vertical structure in the study area. Inter-annual variability was also observed for both species that appeared to respond differently to the environmental factors investigated. Distributions of P. calliantha showed a stronger seasonality and was more correlated with winter water conditions than P. delicatissima, which in turn exhibited a broader temporal distribution and appeared independent from major environmental constraints. This is the first report of the occurrence and dynamics of P. calliantha and P. delicatissima populations in Southern Adriatic coastal waters.

An integrated study was carried out to follow the temporal evolution of microbiological parameters during a 48 h period, in relation to the deep chlorophyll maximum (DCM) at a coastal station. The micro-organisms showed an active role in the environment and a different distribution, without a clear diel cycle. The phytoplankton community, responsible for the DCM, consisted mainly of diatoms. Their distribution in relation to pycnocline showed an opposite trend with respect to picophytoplankton. Total bacterioplankton contributed to enzymatic degradation of particulated organic carbon (by producing β-glucosidase and aminopeptidase), with peaks related to changes in the main water current. We estimated that about 25% of particulate organic carbon per day may be hydrolysed by bacteria. The living bacterioplankton represented 20% of the total. The picophytoplankton fraction contributed significantly to the high values of alkaline phosphatase, suggesting a fast P regeneration. Respiration showed significant co...

Bacterial abundance was investigated in Varano lagoon for a 12 month period. The concentrations were found to be quite high (1.8 ± 2.2 X 10 9 cells l -1 ) as well as being coupled to phytoplankton biomass and phosphorus content. However, an inverse relationship with nitrogen was detected.

The EU Marine Strategy Framework Directive 2008/56/EC (MSFD) defines a framework for Community actions in the field of marine environmental policy in order to achieve and/or maintain the Good Environmental Status (GES) of the European seas by 2020. Microbial assemblages (from viruses to microbial-sized metazoa) provide a major contribution to global biodiversity and play a crucial role in the functioning of marine ecosystems, but are largely ignored by the MSFD. Prokaryotes are only seen as "microbial pathogens", without defining their role in GES indicators. However, structural or functional prokaryotic variables (abundance, biodiversity and metabolism) can be easily incorporated into several MSFD Descriptors (i.e. D1. Biodiversity, D4. Food webs, D5. Eutrophication, D8. Contaminants and D9. Contaminants in seafood) with beneficial effects. The present review provides a critical analysis of the current MSFD descriptors and illustrates the reliability and advantages of the potential incorporation of some prokaryotic variables within the set of indicators of marine environmental quality. Following a cost/benefit analysis against scientific and economic criteria, we conclude that marine microbial components, and particularly prokaryotes, are highly effective for detecting the effects of anthropogenic pressures on marine environments and for assessing changes in the environmental health status. We thus recommend the inclusion of these components in future implementations of the MSFD.

In marine environment phytoplankton and picoplankton are responsible for a bulk of production and nutrient cycling and may give important information about the different seawater habitats. In the present paper, the temporal changes of phytoplankton as well as autotrophic and heterotrophic picoplankton abundance and biomass in two coastal areas in the Gulf of Taranto (Mediterranean Sea) subjected to different levels of anthropogenic pressure were studied and related to the main environmental variables. The two analysed areas were significantly different as regards the abiotic conditions which also varied temporally. Univariate analyses revealed that larger phytoplankton and heterotrophic picoplankton abundance and biomass varied as well. The multivariate analyses showed a complex distribution of the whole planktonic assemblages, which varied in time and space without a decipherable pattern, presumably due to the peculiar spatial-temporal dynamics of the sole autotrophic picoplankton abundance. Significant correlations between planktonic assemblages and environmental variables were discussed by taking into account also the potential role of the considered planktonic components as useful environmental monitoring parameters.

The genus Dinophysis sensu lato is often involved in episodes of Diarrhetic Shellfish Poisoning (DSP) contaminations and human intoxications. To date, several species of this genus have shown toxin production in laboratory, however it is likely that many others could have this capability. Phalacroma rotundatum (Claparède & Lachmann) Kofoid & Michener, allocated by some authors to the genus Dinophysis, is a non-photosynthetic species, which has the potential to produce okadaic acid and its derivatives DTX-1 and DTX-2. This species was observed for the first time along the Southern Adriatic coast of Puglia (Italy) during a two year monitoring program on potentially toxic phytoplankton. Phalacroma rotundatum dynamics was studied in relation to hydrobiological conditions; its seasonal changes appeared rather independent from chemico-physical factors, but were significantly associated with those of phytoflagellates. Toxicity test (Microtox system) on Phalacroma rotundatum cells proved negative.

Some preliminary results of a survey carried out along the Southern Adriatic coasts (Brindisi-S.M. Leuca) are reported in order to contribute to the knowledge of the phytoplankon community of this area. Ten Dinophysis species had been identified, four of them are known to be involved in DSP mussel contamination. Spatio-temporal distribution of Dinophysis spp. is shown.