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Marine bioconstructions are complex habitats that represent a hotspot of biodiversity. Among Mediterranean bioconstructions, those thriving on mesophotic bottoms on southeastern Italian coasts are of particular interest due to their horizontal and vertical extension. In general, the communities that develop in the Mediterranean twilight zone encompassed within the first 30 m of depth are better known, while relatively few data are available on those at greater depths. By further investigating the diversity and structure of mesophotic bioconstructions in the southern Adriatic, we can improve our understanding of Mediterranean biodiversity while developing effective conservation strategies to preserve these habitats of particular interest. The dataset reported here comprises records of benthic marine taxa from algae and invertebrate mesophotic bioconstructions investigated at six sites along the southern Adriatic coast of Italy, at depths between approximately 25 and 65 m. The dataset contains a total of 1718 records, covering 11 phyla and 648 benthic taxa, of which 580 were recognized at the species level. These data could provide a reference point for further investigations with descriptive or management purposes, including the possible assessment of mesophotic bioconstructions as refuges for shallow-water species. Dataset: The dataset is submitted as a Supplementary File. Dataset License: CC-BY [ABSTRACT FROM AUTHOR]

ABSTRACTThis paper presents the results of the 2021 and 2022 field activities carried out at San Nicola Island (Tremiti Islands, Southern Adriatic Sea) by two groups of students as part of the Environmental Geomorphology Field Mapping course held within the Master's Degree in Geological Sciences and Technologies of Earth and Planets at University ‘G. d'Annunzio’ of Chieti-Pescara. Field activities were carried out following an integrated approach that involved morphometric, geological, and geomorphological analyses, supported by the combination of traditional methods with modern survey instruments and techniques. The Main Map (1:2,500 scale) comprehensively depicts the landscape of San Nicola Island, which is affected by both long- and short-term evolutionary processes, as witnessed by widespread slope landforms. The cartographic products presented in this work can represent a useful tool in territorial planning and management, as well as a valuable base for further scientific studies.

Simple Summary: This study describes the composition, abundance, spatial distribution and differences in day/night vertical distribution of ichthyoplankton in the southern Adriatic Sea. Samples were collected from 9 to 18 May 2013, in multiple layers from near the seabed to the surface by the electronic multinet EZ-NET BIONESS (Bedford Institute of Oceanography Net Environmental Sampling System). A total of 20 species, belonging to 20 genera and 13 families, were identified. The community was dominated by Gonostomatidae, followed by Engraulidae, Myctophidae and Photychthaidae. The most abundant species was Cyclothone braueri, followed by Engraulis encrasicolus, Ceratoscopelus maderensis, Cyclothone pygmaea, Vinciguerria attenuata and Myctophum punctatum. An inshore/offshore increasing gradient in biodiversity and abundance was observed. Different weighted mean depths (WMD) were observed for larvae and juveniles. No diel vertical migrations were observed. The high abundance of meso-bathypelagic species in the upper 100 m confirms the epipelagic zone as an important environment for the development of the larval stages of these fish. Studies based on fish early life stages can provide information on spawning grounds and nursery areas, helping to determine the implications for stock biomass fluctuations of recruitment variability. This study describes the composition, abundance, spatial distribution and differences in day/night vertical distribution of ichthyoplankton in the southern Adriatic Sea. Samples were collected within the framework of the COCONET project (Towards COast to COast NETworks of marine protected areas) from 9 to 18 May 2013 by the R/V Urania, using the electronic multinet EZ-NET BIONESS (Bedford Institute of Oceanography Net Environmental Sampling System). A total of 20 species, belonging to 20 genera and 13 families, were identified. Of the collected larvae, 74.3% were meso- or bathypelagic species, 24.7% were epipelagic and 0.9% were demersal. The community was dominated by Gonostomatidae, followed by Engraulidae, Myctophidae and Photychthaidae. The most abundant species was Cyclothone braueri (45.6%), followed by Engraulis encrasicolus, Ceratoscopelus maderensis, Cyclothone pygmaea, Vinciguerria attenuata and Myctophum punctatum. An inshore/offshore increasing gradient in biodiversity and abundance was observed. Different weighted mean depths (WMDs) were observed for larvae and juveniles. No diel vertical migrations were observed. The high abundance of meso- or bathypelagic species in the upper 100 m confirms the epipelagic zone as an important environment for the development of the larval stages of these fish. [ABSTRACT FROM AUTHOR]

Marine bioconstructions are complex habitats that represent a hotspot of biodiversity. Among Mediterranean bioconstructions, those thriving on mesophotic bottoms on southeastern Italian coasts are of particular interest due to their horizontal and vertical extension. In general, the communities that develop in the Mediterranean twilight zone encompassed within the first 30 m of depth are better known, while relatively few data are available on those at greater depths. By further investigating the diversity and structure of mesophotic bioconstructions in the southern Adriatic, we can improve our understanding of Mediterranean biodiversity while developing effective conservation strategies to preserve these habitats of particular interest. The dataset reported here comprises records of benthic marine taxa from algae and invertebrate mesophotic bioconstructions investigated at six sites along the southern Adriatic coast of Italy, at depths between approximately 25 and 65 m. The dataset contains a total of 1718 records, covering 11 phyla and 648 benthic taxa, of which 580 were recognized at the species level. These data could provide a reference point for further investigations with descriptive or management purposes, including the possible assessment of mesophotic bioconstructions as refuges for shallow-water species.

This work presents the results of long-term deep-water observations carried out in the southwestern Adriatic margin. Hydrodynamics and thermohaline measurements were carried out in the last 100 m of the water column using two long-term moorings placed at two different locations along the western sector of the Adriatic continental margin (open slope vs. submarine canyon). The observations, carried out over a period of almost 10 years, made it possible to define the intra- and interannual deep-water dynamics, which are mainly influenced by the passage of cold, dense water. The hydrodynamic field is influenced by seasonal behavior and varies from year to year, with no clear temporal trend or periodicity. Thermohaline properties follow hydrodynamics but also show a climatological trend toward higher temperatures and salinity. The combination and variability of preconditioning factors explains the interannual variability in dense water passage at the mooring sites triggering the formation of dense water in the northern Adriatic. The impulsive nature of the dense water flow, which is difficult to capture with sporadic oceanographic surveys, and its linkage with the large-scale atmospheric circulation make continuous monitoring essential to answer open questions about cascading processes and deep-water dynamics under a global change scenario. [ABSTRACT FROM AUTHOR]

This paper presents the results of the 2021 and 2022 field activities carried out at San Nicola Island (Tremiti Islands, Southern Adriatic Sea) by two groups of students as part of the Environmental Geomorphology Field Mapping course held within the Master’s Degree in Geological Sciences and Technologies of Earth and Planets at University ‘G. d’Annunzio’ of Chieti-Pescara. Field activities were carried out following an integrated approach that involved morphometric, geological, and geomorphological analyses, supported by the combination of traditional methods with modern survey instruments and techniques. The Main Map (1:2,500 scale) comprehensively depicts the landscape of San Nicola Island, which is affected by both long- and short-term evolutionary processes, as witnessed by widespread slope landforms. The cartographic products presented in this work can represent a useful tool in territorial planning and management, as well as a valuable base for further scientific studies. [ABSTRACT FROM AUTHOR]

The performance of both the tectonic uplift and of the 4th-order glacial eustatic sea level fluctuations in controlling the stratigraphic architecture of Quaternary lowstand prograding wedges of the Salento continental shelf (Southern Adriatic sea, Italy) during a time interval spanning from the Middle Pleistocene to the Holocene has been pointed out through the interpretation of high-resolution seismic reflection profiles and their correlation to the curves of the isotopic stratigraphy. Three main transgressive surfaces of erosion (RS1, RS2 and RS3) punctuate the stratigraphic architecture of the Salento continental shelf, separating Quaternary lowstand prograding wedges between them. All along the Middle Pleistocene, increasing the tectonic uplift of the Puglia offshore, combining with 4th-order glacio-eustatic variations, have dealt with the pattern of a broad forced regression prograding wedge, favoring a platform progradation of approximately 15 km. The architectural stacking patterns of the overlying Late Pleistocene and Holocene prograding wedges are controlled by 4th-order glacio-eustatic sea level changes, allowing for the formation of incomplete depositional sequences. In this period, the eustatic signature overcomes the tectonic mark, implying a decline in the uplift of the Apulian foreland in the course of the final 250 ky. [ABSTRACT FROM AUTHOR]

The bamboo coral Isidella elongata is a forest-forming alcyonacean that dwells on deep-sea soft bottoms and is presently found in the Otranto Channel (Southern Adriatic Sea). In this study, we explored the spatial distribution and the demographic structure of the I. elongata facies (IF) over time, along with the diversity of IF-associated fauna in the southern Adriatic Sea, by using a time-series data of 9 years (2012–2020) from the Mediterranean International Bottom Trawl Survey (MEDITS). The spatial distribution of I. elongata was confronted with the fishing effort in the study area over time. This facies showed a constant spatial extent but a decreasing biomass over time. Changes in the basal diameter distribution of the colonies were also observed, with a significant decrease in the sizes from 2014 to 2020. These results suggest an increasing fishery-related impact from a developing deep-sea fishery occurring in the study area. The bamboo coral in the study area represents a hotspot of biodiversity in the context of the bathyal environment. A fisheries-restricted area was recently proposed in the context of the General Fisheries Commission for the Mediterranean at the Otranto Channel to help the conservation of I. elongata in the southern Adriatic Sea. [ABSTRACT FROM AUTHOR]

This work presents the results of long-term deep-water observations carried out in the southwestern Adriatic margin. Hydrodynamics and thermohaline measurements were carried out in the last 100 m of the water column using two long-term moorings placed at two different locations along the western sector of the Adriatic continental margin (open slope vs. submarine canyon). The observations, carried out over a period of almost 10 years, made it possible to define the intra- and interannual deep-water dynamics, which are mainly influenced by the passage of cold, dense water. The hydrodynamic field is influenced by seasonal behavior and varies from year to year, with no clear temporal trend or periodicity. Thermohaline properties follow hydrodynamics but also show a climatological trend toward higher temperatures and salinity. The combination and variability of preconditioning factors explains the interannual variability in dense water passage at the mooring sites triggering the formation of dense water in the northern Adriatic. The impulsive nature of the dense water flow, which is difficult to capture with sporadic oceanographic surveys, and its linkage with the large-scale atmospheric circulation make continuous monitoring essential to answer open questions about cascading processes and deep-water dynamics under a global change scenario.

The 2019 Geomorphological Field Camp at San Domino Island (Tremiti Islands, Southern Adriatic Sea) is the result of geological and geomorphological field work activities carried out by a group of students attending the Geomorphological field mapping course of the Master’s Degree in Geological Science and Technology (University of Chieti-Pescara). The main map (1:5000 scale) was obtained through an integrated approach that incorporates morphometric analysis, geological and geomorphological field mapping, and geomorphological profiles drawing. Activities were carried out by all students, divided into six working groups of three to four persons each. The field camp and field work activities made it possible to produce a detailed thematic map, as a scientific tool to depict the San Domino Island landscape, and to outline some geomorphological issues in terms of possible constraints to landscape evolution, geomorphological processes distribution, and natural hazard assessment.

The performance of both the tectonic uplift and of the 4th-order glacial eustatic sea level fluctuations in controlling the stratigraphic architecture of Quaternary lowstand prograding wedges of the Salento continental shelf (Southern Adriatic sea, Italy) during a time interval spanning from the Middle Pleistocene to the Holocene has been pointed out through the interpretation of high-resolution seismic reflection profiles and their correlation to the curves of the isotopic stratigraphy. Three main transgressive surfaces of erosion (RS1, RS2 and RS3) punctuate the stratigraphic architecture of the Salento continental shelf, separating Quaternary lowstand prograding wedges between them. All along the Middle Pleistocene, increasing the tectonic uplift of the Puglia offshore, combining with 4th-order glacio-eustatic variations, have dealt with the pattern of a broad forced regression prograding wedge, favoring a platform progradation of approximately 15 km. The architectural stacking patterns of the overlying Late Pleistocene and Holocene prograding wedges are controlled by 4th-order glacio-eustatic sea level changes, allowing for the formation of incomplete depositional sequences. In this period, the eustatic signature overcomes the tectonic mark, implying a decline in the uplift of the Apulian foreland in the course of the final 250 ky.

Bryozoan assemblages of three mesophotic habitats, recently found in the Adriatic and Ionian Seas, were investigated in terms of species composition and diversity, colonial growth forms, and species ecological affinity, with the purposes to analyze variations and similarities between the different bioconstructions and to compare the mesophotic assemblages with those of other benthic habitats. Bryozoans came from three sites off the Apulian coast: Monopoli, 30–55-m depth, where scleractinians are dominant; Otranto, 45–64-m depth; and Santa Maria di Leuca, 45–70-m depth, where the bivalve Neopycnodonte cochlear is the main bioconstructor. A total number of 50 species of bryozoans were recorded, accounting for about 10% of the total number of Mediterranean species. Only few species were shared between the three sites, whereas a considerable pool of species was characteristic of each site. The β-diversity and Sörensen similarity analyses highlighted the highest similarity between the two southern sites, Otranto and Santa Maria di Leuca, with respect to the northern site of Monopoli, in agreement with the hydrological pattern of the area. The encrusting zoarial type was the most abundant in each site, and few species with erect, celleporiform and petraliform colonies were found. The Sörensen similarity, based on data of zoarial forms composition, revealed values considerably higher than those based on species composition, thus highlighting the similar ecological role played by the bryozoans in all the sites. Moreover, significant differences between the mesophotic bryozoan assemblages and those of other benthic Mediterranean habitats were highlighted, showing higher affinity with the coralligenous and detritic sciaphilic habitats. The relevant ecological role of bryozoans as binders in the bioconstructions of the Mediterranean mesophotic zone has been exhibited.

The 2019 Geomorphological Field Camp at San Domino Island (Tremiti Islands, Southern Adriatic Sea) is the result of geological and geomorphological field work activities carried out by a group of students attending the Geomorphological field mapping course of the Master's Degree in Geological Science and Technology (University of Chieti-Pescara). The main map (1:5000 scale) was obtained through an integrated approach that incorporates morphometric analysis, geological and geomorphological field mapping, and geomorphological profiles drawing. Activities were carried out by all students, divided into six working groups of three to four persons each. The field camp and field work activities made it possible to produce a detailed thematic map, as a scientific tool to depict the San Domino Island landscape, and to outline some geomorphological issues in terms of possible constraints to landscape evolution, geomorphological processes distribution, and natural hazard assessment. [ABSTRACT FROM AUTHOR]

• Radiometric ages of CWC of the Adriatic Sea shows different colonization periods. • The first occurrence of CWC in the southern Adriatic Sea is dated to the LGM. • The lack of CWC during the S1 documents oxygen deficiency at intermediate depths. • The NAdDW trajectory along the W Adriatic Sea controls the asymmetrical CWC settling. The deep southern Adriatic Sea is home of widespread cold-water coral colonization (Madrepora oculata , Lophelia pertusa , Desmophyllum dianthus) which is at present limited by large to its western (Apulian) margin and central part, including the Bari Canyon system. On the contrary, the eastern side is today almost deprived of significant coral growth and this asymmetrical distribution has been ascribed primarily to the action of the North Adriatic Dense Water (NAdDW) that impinges more efficiently on the Apulian margin. The collection of subfossil specimens of M. oculata , L. pertusa and D. dianthus provided the very first dates for cold-water coral colonization along the eastern margin. Once combined with known distribution of live cold-water corals and fossil occurrences in the southern Adriatic Sea, uranium-series dating provides evidence of (i) coral presence in the southeastern Adriatic during the Last Glacial Maximum (LGM), followed by (ii) a time of basin-wide colonization after the post-Last Glacial Maximum and encompassing the Younger Dryas, (iii) another time of undocumented coral presence with the onset of Sapropel S1. Perturbations of the thermohaline circulation in this sector of the Mediterranean basin might have governed the presence and demise of the resident cold-water coral populations interfering with strength and trajectories of main water masses. It is hypothesized that the achievement of the current asymmetrical distribution did occur since the end of S1 protracting to present time. The post-S1 reorganization likely brought to the current hydrological situation where the influence of NAdDW prevails in the western side and corals are doing at best on its trajectory. The scarcity of datable material makes the proposed scenario open to debate and in need of further supporting evidence. [ABSTRACT FROM AUTHOR]

Abstract Marine picoplankton, unicellular organisms with cell sizes up to 3 μm in diameter, numerically dominate marine ecosystems, encompassing Archaea, Bacteria, Eukarya (protists and fungi) as well as viruses. Autotrophic and heterotrophic picoplankton abundance and community composition with a focus on picoeukaryotes (PEs) were investigated in the winter of 2016 at three stations along a coast-to-offshore transect in the southern Adriatic Sea. Abundances were estimated by flow cytometry, while community composition by Illumina High-Throughput Sequencing (HTS) of 16S and 18S rRNA genes. The photosynthetic picoplankton diversity was also investigated by High-Performance Liquid Chromatography (HPLC) of liposoluble pigments. Heterotrophic bacteria and cyanobacteria (Prochlorococcus and Synechococcus) accounted for up to 7 × 105; 2.3 × 104 and 2.5 × 104 cells mL−1, respectively, while photosynthetic picoeukaryotes peaked with 3 × 103 cells mL−1. Prokaryotes, as revealed by HTS were dominated by Alphaproteobacteria (mainly SAR11, 44.91% of total 16S sequence reads), followed by Gammaproteobacteria (Oceanospirillales and Pseudomonadales , 14.96%), Bacteroidete s (mainly Flavobacteriales , 13%), Cyanobacteria (Prochlorococcus and Synechococcus , 9.52%), Marinimicrobia (SAR406, 7.97%), Deltaproteobacteria (SAR324, 3.83%), Actinobacteria (2.24%) and Chloroflexi (SAR202, 1.90%). Photosynthetic pigment concentrations were very low (12.12 μgL−1 at the most) and taxonomic pigments could be attributed to Prochlorococcus , Synechococcus , Prymnesiophyceae, Bacillariophyceae, Chrysophyceae, and Prasinophyceae. HTS data revealed that PEs were dominated by heterotrophs, such as Syndiniophyceae, parasitic dinoflagellates (79.67% of total 18S sequence reads), Dinophyceae (8.7%) and the radiolarians Collodaria belonging to Sphaerozoidae (22.1%) and Spumellaria (5.0%). On the other hand, photoautotrophs, including Chlorophyta (Mamiellophyceae, Prasinophyceae, Trebouxiophyceae, and Ulvophyceae), Stramenopiles (Bacillariophyta, Chrysophyceae, Dictyochophyceae, Pelagophyceae), photoautotrophic Cryptophyta and some Haptophyta (Prymnesiophyceae), did not exceed 5% of total sequence reads. This study provides the first snapshot of the PEs diversity in oligotrophic euphotic waters of the southern Adriatic Sea, hence setting the stage for large-scale surveying and characterization of the eukaryotic diversity in the entire basin. [ABSTRACT FROM AUTHOR]

This study documents for the first time the taxonomic composition of the nematode community and the number of free–living nematode species in Lake Varano, Southern Adriatic Sea, Italy. The nematode community was mainly composed of species typical of fine sediments that usually prevail in transitional environments (TEs). An overall high number of nematode species was recorded (55), belonging to 36 genera in 17 families. These values are highly comparable to those reported for other Italian TEs, but appear lower than those recorded in other European brackish–water systems, probably in relation to the low salinity range of Lake Varano. Forty taxa were identified up to species level, thus increasing the number of the nematode marine species known for the Italian coasts from 443 to 463, for the Adriatic basin from 310 to 313, and for the Southern Adriatic sector from 37 to 77. Considering the importance of this phylum in the assessment of ecological quality and the great vulnerability of the Adriatic Sea ecosystems, an intensification of sampling efforts should be planned, especially in the Central–Southern part of the basin. Such a plan would provide new insights into the biogeography of one of the most important components of the benthic domain and potentially yield new information about the climate warming effects on the Adriatic Sea.

This study documents for the first time the taxonomic composition of the nematode community and the number of free–living nematode species in Lake Varano, Southern Adriatic Sea, Italy. The nematode community was mainly composed of species typical of fine sediments that usually prevail in transitional environments (TE). An overall high number of nematode species was recorded (55), belonging to 36 genera in 17 families. These values are highly comparable to those reported for other Italian TE, but appear lower than those recorded in other European brackish–water systems, probably in relation to the low salinity range of Lake Varano. Forty taxa were identified up to species level, thus increasing the number of the nematode marine species known for the Italian coasts from 443 to 463, for the Adriatic basin from 310 to 313, and for the Southern Adriatic sector from 37 to 77. Considering the importance of this phylum in the assessment of ecological quality and the great vulnerability of the Adriatic Sea ecosystems, an intensification of sampling efforts should be planned, especially in the Central–Southern part of the basin. Such a plan would provide new insights into the biogeography of one of the most important components of the benthic domain and potentially yield new information about the climate warming effects on the Adriatic Sea.

Bacteria are the most important microorganisms in the world oceans, accounting for up to 75% of the total biomass. They are responsible for fundamental biogeochemical processes and therefore often used as ecological indicators. In this study, bacteria were quantified by flow cytometry and their diversity assessed by High Throughput Sequencing (HTS) in the southern Adriatic Sea. The most abundant bacterial groups were also quantified by qPCR. The samples were collected from the surface to the seabed over a total of 16 different depths at four stations during the late winter BIOTA (BIO-Tracing Adriatic water masses) cruise conducted in March 2016. The investigated area showed unusual water mass properties and was characterized by a shallow mixed layer, which differed from the usual winter convection conditions, typical of middle-altitude ecosystems and important for the seasonal picoplankton dynamics of this area. Heterotrophic bacteria were separated into HNA (relative High Nucleic Acid content) and LNA (Low Nucleic Acid content) subpopulations with abundances up to 1.8 × 10 5 and 8.8 × 10 5  cells mL −1 , respectively. HNA dominated at offshore stations reaching their maximum at depths below the euphotic zone. The bacterial community was dominated by Alphaproteobacteria , accounting for >40% of the total sequence reads and were mainly represented by the SAR11 clade (90.84%), followed by Marinimicrobia (18% of the total sequence reads), mainly represented by clade SAR406 (8.44%). Distinctive bacterial groups were found in the euphotic layer ( Bacteroidetes and Actinobacteria ) and aphotic layer samples ( Deltaproteobacteria , Marinimicrobia , Chloroflexi , Acidobacteria and Planctomycetes ). Results of the qPCR analyses further confirmed HTS results with highest abundances obtained for Alphaproteobacteria, followed by Gammaproteobacteria and Bacteroidetes . The adopted multiple approach, combining different molecular tools, critically supported by optics and flow cytometry, reveal changes in the bacterial assemblages during the unusual thermohaline conditions observed in 2016 in the southern Adriatic Sea. [ABSTRACT FROM AUTHOR]

Dense water (DW) formation commonly occurs in the shallow Northern Adriatic Sea during winter outbreaks, when there is a combination of the cooling of surface waters by the winds and high salinity as a result of reduced river inputs. These DWs subsequently propagate southwards over a period of weeks/months, eventually arriving in the Southern Adriatic Sea. The investigation is based on a new nonhydrostatic (NH) formulation of the 3D finite element model SHYFEM that is validated for a number of theoretical test cases. Subsequently this model is used to simulate, through high-resolution numerical simulations, an extreme DW event that occurred in the Adriatic Sea in 2012. We perform both hydrostatic (HY) and NH simulations in order to explicitly see the impact of NH processes on the DW dynamics. The modeled results are compared to observations collected in the field campaign of March–April 2012 in the Southern Adriatic Sea. The NH run correctly reproduces the across isobath bottom-trapped gravity current characterizing the canyon DW pathways. It also more accurately captures the frequency and intensity of dense water cascading pulsing events, as the inclusion of NH processes produces stronger currents with different DW mixing characteristics. Finally, the NH run simulates internal gravity waves (IGW), generated during the cascading at the edge of the canyon, which propagate downslope. This IGW activity is not captured in the HY case. [ABSTRACT FROM AUTHOR]

Sedentary polychaete Sabellaria spinulosa (Leukhart, 1849) is a suspension feeder that builds tubes by cementing together terrigenous particles. Under a set of environmental conditions, S. spinulosa can form reefs (consisting of hundreds or thousands of worm tubes) that can vary greatly in thickness, size and patchiness. The more-developed reefs form in areas with a large and continuous supply of sand, turbulent water, nutrient availability and rocky seafloor. Recently, for the first time in the Mediterranean area, a large reef of S. spinulosa has been discovered along the northern Gargano coast at Torre Mileto (Adriatic Sea, southern Italy). In this paper, we will detail the main sedimentological data of this worm reef. In order to evaluate the kind of terrigenous particles involved in the worm tube constructions, detailed grain-size and petrographic analyses were carried out on both reef and soft-sediment substrate samples. It is demonstrated that S. spinulosa selects sands on the basis of their grain size and shape, and not their composition. It is also shown that some seasonal variations of these parameters are the result of the interplay between reef growth and degradation periods mainly related to physical processes. In particular, the degradation stages seem to be induced mainly by storm wave action, while the reef growth is the result of the complex interaction between ecological and physical processes. [ABSTRACT FROM AUTHOR]

The qualitative and quantitative composition of culturable heterotrophic bacteria in water samples from the Southern Adriatic Sea of Italy was examined. Water samples were collected monthly, for a year, at 16 stations along the coast line between Brindisi and Santa Maria di Leuca. The results obtained described the heterotrophic bacterial community over an annual cycle. Mean values of bacterial densities were 5.3 x 104 CFUml-1 in Brindisi, 5.8 x 104 CFUml-1 in S. Cataldo, 4.3 x 104 CFUml-1 in Otranto and 6.7 x 104 CFUml-1 in S. M. di Leuca. The differences in bacterial densities between the sites considered were estimated. The hydrodynamic circulation, the trophism and the geographical position of the examined sites contribute to justify the different bacterial density trends. The bacterial community consisted mainly of the genera Aeromonas, Pseudomonas, Photobacterium and Flavobacterium. The Enterobacteriaceae represented a considerable fraction of the bacterial community in the Southern Adriatic Sea. Bacilli were predominant among the Gram positive bacteria. The enzymatic versatility of the observed genera suggest their importance in organic matter turnover of this oligotrophic ecosystem.

A tephrochronological investigation was carried out at site ND14Q (1013 m of water depth), located in the southern Adriatic Sea, offshore the Gargano promontory. It was drilled in the frame of The NextData Project (www.nextdataproject.it , 2011-2013), focused on paleoclimate research. To obtain a composite and well preserved deep marine record, three cores were raised at the study site. Twelve primary cryptotephra and one tephra were analysed in terms of major-element content and correlated with a total of sixteen eruptive events. The studied materials display K-alkaline and subalkaline features pointing to a correlation with the Somma-Vesuvius, Campi Flegrei and Lipari Island (Aeolian Arc) volcanic activity occurred during the Late Pleistocene-Holocene. In detail, major marker tephra of the central Mediterranean have been recognized, among which the Phlegraean Neapolitan Yellow Tuff (ca. 15 ka), Pomici Principali (ca. 12 ka BP) and Astroni-Agnano-Monte Spina (ca. 4.2 ka - 4.4 ka BP) eruptions and, for the first time in this area, the Vesuvian 79 CE event. The very well preserved Mercato (ca. 9 ka BP) and Fiumebianco-Gabellotto (ca. 8.4 ka BP) cryptotephra have also been found in the sapropel S1 interval of the succession, which definitely records the last ca. 22 kyr (Pomici di Base tephra). A number of other Plinian and sub-Plinian events also occur and the availability of multiple cores provided new insights into their temporal relation such as between AP2 and Astroni 6 eruptions. The identification of tephra sourced by well-dated volcanic events, along with several AMS 14C age results, allowed an accurate chronological framework for the composite tephrostratigraphic record, thus providing accurate ages for those deposits with an uncertain correlative event. In addition, stratigraphic evidences in the core replicates at ND14Q site showed that several intervening factors affect preservation and traceability of cryptotephra deposits in the marine realm posing main critical issues on volcanological and paleoclimate research. • Three core replicates provide a composite tephra record at marine site ND14Q. • Retrieving of recent tephra and cryptotephra depends on coring technological devices. • Chronostratigraphy of the Astroni and AP multiple events is better constrained. • Lagno Amendolare and Neapolitan Yellow Tuff tephra show chemical similarities. • The lack of an expected tephra does not necessarily testify to a sedimentary hiatus. [ABSTRACT FROM AUTHOR]

Abstract: Enhanced mixing of North Adriatic Dense Water (NAdDW) occurs in a strong frontal region as this cold and fresh intermediate water enters the southern Adriatic basin and meets warm and salty Modified Levantine Intermediate Water (MLIW) coming from the Ionian Sea. This study examines how NAdDW was mixed and transformed as it traveled southward from the Gargano to the Bari region and investigates the pathway and intrusion patterns of MLIW in late winter/spring 2009. Hydrographic data are analyzed to compute source water fractions via a least-squares analysis method and combined with ADCP data to compute source water volume fluxes. Results show that despite an anomalous low year for NAdDW production in the Adriatic, a warmer, fresher and lighter version of traditional NAdDW (i.e. 2009 NAdDW) endured its journey from Gargano to Bari. In the Gargano region, 2009 NAdDW (with fractions up to 80–90%) traveled southward in a non-continuous thin, dense vein between 35m and 100m isobaths, with diluted cores extending to 140m depth, and with fluxes of −0.05Sv, to the southeast, south of PalagruzË¿a Sill. Near the sill, 2009 NAdDW was further mixed and diluted with MLIW and surface water. By the time it reached the Bari region, the 2009 NAdDW fraction in the water column was reduced to about 20%. MLIW intrusions observed over the Sill and in northern sections of the study area suggest a splitting of MLIW pathways (stemming from the main South Adriatic rim pathway) towards the central Adriatic. Source water fraction results combined with velocity and seismic oceanography data show that eddies in the study area are one mechanism for the generation of MLIW intrusions towards the northwest. [Copyright &y& Elsevier]

Abstract: The spatial and temporal variability of phytoplankton were investigated in the southern Adriatic Sea in the period November 2006–June 2008. Three stations were sampled along the Bari–Dubrovnik transect with a seasonal frequency (except summer 2007 and spring 2008) at four depths (surface, maximum fluorescence depth and two intermediate depths), with the aim of analyzing the structure of phytoplankton community and evaluate the standing stocks of the three size fractions (pico-, nano- and microphytoplankton). Abundances were on average 5.41×107±5.97×106 cellsl−1 for picophytoplankton, 1.00×106±6.70×104 cellsl−1 for nanophytoplankton and 2.16×104±7.46×103 cellsl−1 for microphytoplankton. Total biomass ranged from 8.5 to 80.7μgCl−1. The highest values were recorded in April 2007 (38.4±5.9μgCl−1), and the lowest ones in February 2008 (13.8±1.5μgCl−1). Picophytoplankton was generally the most abundant phototrophic fraction (on average, 96% of the total abundances and 49% of the total biomass), while nano- and microphytoplankton provided a minor contribution (4% and less than 1% of total abundance and 35% and 16% of total biomass for nanophytoplankton and microphytoplankton, respectively). A decreasing gradient from west to east was observed for pico- and nanophytoplankton abundances and for total biomass. The low biomass values and the dominance of the autotrophic picoplankton fraction in the whole area reflected a general oligotrophic condition. The easternmost station (AM9), characterized by the lowest phytoplankton abundances and biomass and low nutrient concentrations, resulted in still more oligotrophic condition and probably influenced by the Ionian Surface Water (ISW), coming from the eastern Mediterranean. [Copyright &y& Elsevier]

Abstract: In the framework of the Vector Project downward particle fluxes have been measured in a station located in the centre of the South Adriatic Pit from November 2006 to August 2008. Sediment trap samples were collected at two different depths, below the photic layer (168m) and near the bottom (1174m), and analysed for total mass flux, for total and organic carbon, total nitrogen, carbonate, stable isotope of organic carbon (δ13Corg) and biogenic silica contents. The results have been integrated and compared with data obtained from previous research projects, carried out in the Southern Adriatic area in 1994–1995 and 1997–1998. Fluxes of particulate matter showed high seasonal and interannual variability, with maximum values in late winter–spring season. The organic carbon flux, followed the same seasonal trend, with higher values below the photic zone, and peaks in spring, related to blooms of silica and/or carbonates phytoplankton organisms (e.g., diatoms, coccolithophorids). The organic carbon export from the photic layer was of 5.2 and 2.1gCm−2 y−1 reached the bottom. Climatological cycles and, in particular, the maximum depth of the convective vertical mixing determined the high fluxes measured in 1998 and in 2008 springs. Total mass fluxes measured at the bottom trap were twofold those measured below the photic layer, and showed a high lithogenic fraction, highlighting the presence of advective processes that appear particularly active in the area. These processes can be correlated with the spreading of dense waters coming from the north and central Adriatic, generally observed in spring. The elemental and isotopic composition of bottom trap samples, resulted similar to that of samples collected in the south-western Adriatic slope, corroborating the assumption that lateral advection other than vertical input were contributing to bottom particle fluxes. [Copyright &y& Elsevier]

Abstract: We present the first results from the seismic oceanography (SO) cruise ADRIASEISMIC where we successfully imaged thermohaline fine structures in the shallow water environment (50–150m) of the southern Adriatic Sea during March 2009 using a compact two GI-gun seismic source. The SO observations are complemented with traditional oceanographic and micro-structure measurements and show that SO can operate over almost the entire water column except (in our experimental layout) for the uppermost 50m. After processing to enhance the signal-to-noise ratio, the seismic reflection data have a vertical resolution of ~10m and a horizontal resolution of ~100m and provide a laterally continuous map of significant thermohaline boundaries that cannot be achieved with conventional physical oceanography measurements alone. ADRIASEISMIC specifically targeted structures in shallow waters, namely along the western margin of the southern Adriatic Sea, between the Gargano peninsula and the Bari canyon, and imaged the Northern Adriatic Dense Water (NAdDW), a bounded cold and relatively dense water mass flowing from the northern Adriatic Sea. The seismic data acquired in Bari canyon and offshore of the Gargano promontory show many regions of strongly reflecting shallow structures, and the incorporation of XBTs measurements with these data demonstrate that they can be interpreted in terms of temperature structures and gradients. In the Gargano region several warm water intrusive structures are mapped along with the offshore transitional edge of cold waters of strong NAdDW influence. In Bari Canyon, waters with NAdDW influence are further mapped extending over the shelf and off the slope into a 5km long tongue extending offshore between depths of 200 and 300m. More generally, even though neither cascading nor open-ocean deep convection process appeared to be evident during March 2009, the SO approach was able to map details of thermal features not resolved by even closely spaced XBT measurements. [Copyright &y& Elsevier]

Coastal systems are sensitive to eutrophication and organic matter (OM) produced in such systems influences the fate and distribution of other microconstituents and pollutants. The Boka Kotorska Bay is a jeopardized karstic area due to anthropogenic pressures. The concentrations of dissolved organic carbon (DOC) increase from spring to autumn months, with the values ranging from 0.64 to 1.43 mg C L'. Particulate organic carbon (POC) represents a significant portion of OM, up to 43% of total organic carbon (TOC). The concentrations of surface active substances are typical of coastal seawater, ranging from 0.026 to 0.311 mgL-1 equiv. Triton-X-100, with an increase in the spring/summer months. The normalized surfactant activity values were significantly higher than in other parts of the Adriatic. The presence of organic ligands and particles contribute to the copper complexing capacity values which are in general higher (up to 714 nmolL-5 compared to those found in other coastal areas. Even though preconditions were documented for the inner part of Kotor Bay i.e. elevated nutrient concentrations that lead to high biological production within the system and hence the accumulation of reactive organic matter in spring! summer months, our integrated chemical-biological approach showed that no eutrophic episodes were detected in the period 2008/2009. [ABSTRACT FROM AUTHOR]

Abstract: In the present study we evaluated the degree of microbial water pollution along the coast line between Brindisi and Santa Maria di Leuca (Southern Adriatic Sea) as well as the culturable heterotrophic bacteria abundances and biodiversity in relation to the microbiological quality of the water. A total of 3773 colonies were isolated, subcultured and identified by several morphological, cultural and biochemical methods including the standardized API 20 E and API 20 NE tests. Along the examined coastal tract the microbial pollution indicators were always below the tolerance limits for bathing waters defined by the CEE directive, suggesting a good sanitary quality. Concerning culturable heterotrophic bacteria, different temporal density trends were observed in the four sites in relation to their geographical position. A positive relationship between the bacterial abundances and the temperature was observed in S. Cataldo and Otranto. The culturable bacterial community was mainly composed of the genera Aeromonas, Pseudomonas, Photobacterium and Flavobacterium. The Enterobacteriaceae family represented a conspicuous component of the bacterial community too. Bacilli were predominant among the Gram-positive bacteria. Of interest is the isolation of yeasts (2% at the surface and 1% at the bottom) taking into account their capability of biodegradation of various materials. Because of the low level of microbial pollution recorded, our results are indicative of the natural variation and diversity of the culturable bacterial community in such an oligotrophic ecosystem and could represent a good point of comparison with other ecosystems as well as a baseline for long term studies aimed to evaluate the effects of environmental fluctuations and human impacts on this aspect of biodiversity in coastal areas. [Copyright &y& Elsevier]

Abstract: The Mediterranean Sea is at the transition between temperate and tropical air masses and as such of importance for studying climate change. The Gulf of Taranto and adjacent SW Adriatic Sea are at the heart of this region. Their sediments are excellently suited for generating high quality environmental records for the last millennia with a sub-decadal resolution. The quality of these records is dependent on a careful calibration of the transfer functions used to translate the sedimentary lipid signals to the local environment. Here, we examine and calibrate the and TEX86 lipid-based temperature proxies in 48 surface sediments and relate these to ambient sea surface temperatures and other environmental data. The -based temperatures in surface sediments reflect winter/spring sea surface temperatures in agreement with other studies demonstrating maximum haptophyte production during the colder season. The TEX86-based temperatures for the nearshore sites also reflect winter sea surface temperatures. However, at the most offshore sites, they correspond to summer sea surface temperatures. Additional lipid and environmental data including the distribution of the BIT index and remote-sensed chlorophyll-a suggest a shoreward increase of the impact of seasonal and spatial variability in nutrients and control of planktonic archaeal abundance by primary productivity, particle loading in surface waters and/or overprint by a cold-biased terrestrial TEX86 signal. As such the offshore TEX86 values seem to reflect a true summer signal to the effect that offshore and TEX86 reconstruct winter and summer temperature, respectively, and hence provide information on the annual temperature amplitude. [ABSTRACT FROM AUTHOR]

An update of the spatial distribution and bio-ecological features of Posidonia oceanica (L.) Delile meadows spread along the coasts of the southern Adriatic and northern Ionian Seas (Apulia region, southern Italy) is reported. Mapping carried out in 2004 indicated a remarkable reduction in the spatial distribution of P. oceanica meadows in the southern Adriatic Sea, mostly northwards of Bari, when compared with 1991 data. By contrast, in the northern Ionian Sea, the spatial distribution seems to be more stable. The P. oceanica meadows covered ∼330 km2 distributed along a total of 320 linear km coastline, mostly on the southern side of Apulia. Within natural variability, the differences in bio-ecological features could be due mainly to the presence of anthropic disturbance (urban, industrial and tourist pressure) rather than a significant geographical gradient between the Adriatic and Ionian Seas. However, the mean density values recorded in almost all the Adriatic stations fall within the 'lower sub-normal density' (LSD) range. By contrast, the mean density values observed in the Ionian meadows were generally within the 'normal density' (ND) range. [ABSTRACT FROM AUTHOR]

The toxic benthic dinoflagellate Ostreopsis ovata causes harmful algal blooms. During five years, citizens have monitored blooms of O. cf. ovata along the coast of Molfetta city facing the Adriatic Sea. Coscinodiscus spp., Licmophora spp., Gyrosigma spp. and Achnantes spp. diatoms were also quantified. O. cf. ovata was detected from spring up to winter, however, blooms always occurred in summer. Correlation with nine weather parameters was relatively strong with seawater temperature, dew point and air temperature. Dew point has never been reported before as key parameter. Blooms of O. cf. ovata were preceded by lag period during which conditions permitted proliferation but no proliferation observed. Furthermore, dew point, seawater and air temperature only moderately correlated with proliferation of Coscinodiscus spp. However, correlation between blooms of O. cf. ovata and Coscinodiscus spp. was relatively strong. Correlation between proliferation of O. cf. ovata and Gyrosigma spp. was very weak, while moderate and negative with Licmophora spp. or Achnantes spp. • O. cf. ovata was detected along the coast of Molfetta from spring up to early winter. • Major bloom of O. cf. ovata occurs in summer and can be followed by minor blooms. • O. ovata blooms occur after a lag period required to fulfil the conditions of growth. • O. cf. ovata proliferation correlates with seawater/air temperature and dew point. • O. cf. ovata proliferation strongly correlates with that of Coscinodiscus spp. [ABSTRACT FROM AUTHOR]

In August 2003, dense turfs formed by the filamentous red alga Womersleyella setacea (Hollenberg) R. E. Norris were found in the open part of the Bay of Boka Kotorska, on the shore of Montenegro (southern Adriatic Sea). The habitat and morphology of the alga are described and the impact of the massive development of this species on the structure of the algal communities is discussed. [ABSTRACT FROM AUTHOR]

Abstract: To define the sediment transport pathways along the southern Adriatic shelf and slope, two oceanographic cruises were carried out in the southern Adriatic, in July 2004 and in March–April 2005. To study the role of the Bari Canyon System on sediment dispersal, three moorings, including sediment traps and current meters, have been deployed near the bottom, at depths of ∼600 m, for one year (March 2004–March 2005). Two moorings were deployed within the canyon (station B in the northern branch and station C in the southern branch) and one on the adjacent open slope, north of the canyon system (station A). Total mass fluxes (TMFs) measured by sediment traps were always higher in the canyon than on the adjacent slope. The highest values were measured at station C (average 8.07 g m−2 d−1), roughly double those of station B (3.07 g m−2 d−1), and the lowest outside the canyon at station A (1.69 g m−2 d−1). The highest TMF were recorded in spring 2004, a period characterized by the lowest water temperatures and the highest current speeds (up to 72 cm−1), which were associated with the highest across-slope current component, along the canyon axes. The simultaneous variations of fluxes occurring at the three stations imply that similar processes are active along the entire southern Adriatic margin, and that they are amplified inside the canyon. In spring a vein of southward flowing North Adriatic Dense Water (NAdDW) was observed along the Adriatic shelf. This was related to an enhanced across-slope current component, which was responsible for the higher particle fluxes, both on the open slope and at the canyon stations. These data suggest that the Bari Canyon is an efficient conduit for sediment from the Adriatic continental shelf to the deep basin. Downcore profiles of 210Pb in sediments collected below the traps have been used to estimate sediment mass accumulation rates (MARs) on a century scale. On the open slope, the annual trap flux recorded in 2004–2005 was lower than MAR. On the contrary, in the Bari Canyon, the annual trap flux was higher than MAR, indicating that the lateral advection of particles becomes predominant and that a fraction of the particles intercepted by sediment traps was only in transit through the canyon. [Copyright &y& Elsevier]

The concentrations of some heavy metals (Zn, Cu, Mn, Pb, Ni and Cd) were measured in surface coastal waters of the southern Adriatic Sea, in the framework of the Interregional Program II (INTERREG Italy­Albania). Seven stations were positioned along the Albanian shoreline, at a distance of 500 m from the coast, while the remaining stations were located on inshore­offshore transects along the Adriatic side of Apulia. Concentrations exhibited relatively low values, lower (or similar) than those observed in other Italian coastal areas and generally much lower than at other sites of the coastal Mediterranean. Lead (and to a lesser extent cadmium) showed the most even distribution throughout the study area, most likely resulting from atmospheric inputs. Harbours and river outlets were identified as critical points for the input of the remaining trace elements along both Apulia and Albania. In the large majority of stations, bioassays with the sea urchin Paracentrotus lividus highlighted moderate toxic effects of sea water on these organisms. Heavy metal concentration levels measured in the study area are not directly related to embryotoxicity, probably because they are not high enough to determine toxic effects upon biota, and=or because elements other than metals are of major importance in the coastal area of the southern Adriatic Sea. [ABSTRACT FROM AUTHOR]

Coastal marine ecosystems host complex microbial communities whose composition and metabolism are influenced by continental inputs and mesoscale properties of seawater masses. The identifying traits of the phytoplankton and bacteria such as biomass, size, shape and their metabolism related to organic matter production and degradation, recognized as indicators of the functioning of an ecosystem, were observed in the Gulf of Manfredonia (South Adriatic Sea, Italy) in late spring. This Gulf area is characterized by terrestrial inputs and mesoscale circulation influence such as coastal waters flowing southward from the North Adriatic and offshore waters interested by the Ionian Sea. Water samples were grouped in clusters (Coastal, Intermediate, Offshore and Deep Systems) according to the water column properties. Phytoplankton community biomass and composition, autotrophic and total prokaryotic abundances and microbial metabolism such as enzyme activity rates and prokaryotic heterotrophic production were analyzed to elucidate the trophic pathways with the objective to infer on the ecosystem status. As expected, size-fractionated phytoplankton biomass and production showed greater concentration in coastal waters with prevalence of the largest fractions (micro- and nano-) supported by the diatoms. Conversely, lower biomass and production were measured in all off-shore waters, mainly sustained by smallest fractions (nano-sized phytoflagellates and picophytoplankton). Total and autotrophic prokaryotic abundance decreased from coastal to offshore stations, inversely with respect to cell volume. Prokaryotic heterotrophic production was just below 50% compared to that of phytoplankton in all waters, evidencing an active biomass synthesis. High alkaline phosphatase and leucine aminopeptidase in coastal and offshore waters suggested the quick regeneration of Phosphorus and protein decomposition, respectively. Different levels of phytoplankton-bacteria association might provide a tool to define the ecological status of the studied system in the observed period; an approach to ecosystem assessment exportable to other coastal systems is proposed. [ABSTRACT FROM AUTHOR]