Many hirundine species construct their nests by carrying mud particles from adjacent areas. This ... more Many hirundine species construct their nests by carrying mud particles from adjacent areas. This study aimed to investigate for the first time the materials that mud-nesting hirundines choose for nest construction from a mineralogical and sedimentological perspective. For this purpose, we sampled nests of three sympatric species, namely the Barn Swallow (Hirundo rustica), the Red-rumped Swallow (Cecropis daurica) and the House Martin (Delichon urbicum), from southeastern Europe. Our results showed that all species tend to use clay minerals as a cement and especially smectite and illite and if these minerals are not present in the adjacent area, they use halloysite, kaolinite or chlorite. The amounts of clay minerals in the nests are generally low indicating that the studied species can accurately identify the properties of the nesting materials. Most of the non clay minerals that they use are the common, easily accessible colourless or white minerals with low specific gravity values such as quartz, feldspars and calcite. Grain size distribution analysis revealed that the amount of clay sized grains in the mud nests of all three species is relatively low, while the amount of larger grain particles decreases when the size of the non clay minerals is small. The Red-rumped Swallow showed an increasing preference for larger grain size particles and quartz, the Barn Swallow for finer grain size particles and calcite, and the preferences of the House Martin are in between the other two species. The three hirundine species present different nest building strategies and depending on the nest architecture, each of them seems to show preference for specific minerals and specific grain sizes. Swallows and martins (Hirundinidae) are small, aerial insectivorous passerines that nest either in excavated holes in banks or in cups built mainly of mud and organic material 1. Five migratory members of this family breed in Southern Europe, i.e. the Sand Martin (Riparia riparia), the Crag Martin (Ptyonoprogne rupestris), the House Martin (Delichon urbicum), the Barn Swallow (Hirundo rustica) and the Red-rumped Swallow (Cecropis daurica). The last three species build mud nests in sheltered locations, principally in rural areas and human settlements, though the nest style differs among the three species 1. House Martins are generally colonial breeders, closely associated with buildings, but large colonies can also be found on cliffs. They build an enclosed mud nest with the entrance at the top, usually attached to eaves or overhangs (Fig. 1). Red-rumped Swallows are generally solitary and breed mainly in mountainous areas with cliffs and coastal areas but also in towns and villages. They build a completely closed semi-spherical nest of mud with a tunnel entrance, under overhangs, bridges, eaves or in caves (Fig. 1). Contrary, Barn Swallows, a typical farmland species, build open-topped mud cups reinforced with straws and plant material (Fig. 1), usually adhered to beams, walls or ledges of houses, in barns or in sheds 2,3. Mud nesting hirundines, such as the House Martins and the Red-rumped Swallows, invest enormous effort in nest construction, as they might need to carry more than 1000 pellets of wet mud within a period of a couple of weeks 4-6 .
During the last few decades, X-ray attenuation systems have been established as standard techniqu... more During the last few decades, X-ray attenuation systems have been established as standard techniques in geosciences and as excellent scientific tools for the analysis of sedimentary facies and structures. In the present study, we use two non-destructive and high-resolution systems (computed tomography, X-ray fluorescence) to address all sedimentological facies and structural characteristics on a 6 m long, partly laminated sediment record, from Vouliagmeni lake, located at the eastern part of the Corinth Gulf, Greece. Vouliagmeni lake is the deepest coastal lake in Greece, and its location is of great importance since it is located in one of the most tectonically active regions in the world. The chronological framework of the retrieved sediment sequence spans the last 12,000 years, with alternations of laminated and non-laminated sections. The annual accumulation of the laminated sequences was determined through the radionuclide concentration of 14 samples. Scanning tomography was performed with a medical CT scanner and a µCT scanner, aiming to compare the potentials and variations of both methods. Lamination boundaries, event layers (turbidites) and sediment deformations were distinguished through processing the extracted 3D rendered volumes, after applying ranges depending on Hounsfield (HU) values. Microscopic analysis revealed three main layer types in the varve sequences that were examined, attributing to summer/spring, autumn and winter deposits. Statistical analysis of the elemental composition, magnetic susceptibility (MS) measurements and HU values revealed three clusters/facies, reflecting climatic and in-lake hydrological changes. Cluster A emulates sedimentation during arid conditions, while Cluster B reflects humid conditions with increased precipitation and erosion. Cluster C represents sequences with homogenous Ca-rich sediment. Our proposed workflow highlights the possible correlation between the non-destructive variables that were measured, but also the variations and applications of each method and software used during this study.
Multidisciplinary studies in coastal systems of the eastern Mediterranean region have proven to b... more Multidisciplinary studies in coastal systems of the eastern Mediterranean region have proven to be excellent tools in understanding paleoenvironmental, paleoecological, and paleoclimatic changes that took place during the Holocene period, and how these changes interacted with urban development and growth. This paper presents sedimentological, high-resolution x-ray fluorescence (XRF scanning), micropaleontological, and x-ray diffraction (XRD) data from three shallow sediment cores that were retrieved from Aliki (ancient Siphai or Tipha) salt pond. The study area is located in a unique, highly tectonic geographical region, at the northeast part of the Gulf of Corinth in Greece. Beachrock deposits that form a barrier between the salt pond and the marine environment seem to play an important role in the evolution of the area. The chronological framework was set at around 3100 cal. BP by four 14 C radiocarbon dates, and the evolutionary model that was established indicates four different changes taking place during this period at the study area. From around 3100 to 1600 cal. BP, a transition from a closed to an open lagoonal environment was identified, interrupted by a fluvial terrestrial deposit at around 2500 cal. BP. A shift toward a closed lagoonal system at around 1600 cal. BP and the establishment of a salt pond environment seem to correlate with tectonic activity. The study provides important information about the evolution of coastal landscape in such a tectonic active region and points the interaction between regional human activity and climatic changes during the late-Holocene period.
In the present study we present preliminary results of Zakynthos Alikes lagoon, which is one of t... more In the present study we present preliminary results of Zakynthos Alikes lagoon, which is one of the most seismically active regions of Greece. In order to estimate-interpret the Holocene evolution of the area and to reconstruct the palaeonvironmental changes, we based on the data of a 21 m sediment core. Sediment types, structure, colour, as well as contact depths and bed characteristics, were recorded in the field. Standarised sedimentological analysis were carried out, on 46 samples including grain size analysis, calculation of moment measures, and micro-and molluscan fossils of 17 selected samples. Moreover, radiocarbon age determinations have been made on individual Cardium shells from two horizons and whole-core Magnetic Susceptibility (MS) measurements were taken. The interpretation of depositional environments suggests a coastal environment (restricted-shallow) with reduced salinity such as a lagoon margin and in a tidal flat and/or marsh particularly. The maximum age of the study sediments is about 8500 BP. The rate of sedimentation between 8280 BP and 5590 BP was 5.3 mm/yr and between 5590 BP and modern times 1.03 mm/yr. The rate of sedimentation was higher until mid-Holocene while decrease after to 1.03 mm/yr, results which are similar to other coastal areas of western Greece.
Bacterial systems have gained wide attention for depolymerization of lignocellulosic biomass, due... more Bacterial systems have gained wide attention for depolymerization of lignocellulosic biomass, due to their high functional diversity and adaptability. To achieve the full microbial exploitation of lignocellulosic residues and the cost-effective production of bioproducts within a biorefinery, multiple metabolic pathways and enzymes of various specificities are required. In this work, highly diverse aerobic, mesophilic bacteria enriched from Keri Lake, a pristine marsh of increased biomass degradation and natural underground oil leaks, were explored for their metabolic versatility and enzymatic potential towards lignocellulosic substrates. A high number of Pseudomonas species, obtained from enrichment cultures where organosolv lignin served as the sole carbon and energy source, were able to assimilate a range of lignin-associated aromatic compounds. Comparatively more complex bacterial consortia, including members of Actinobacteria, Proteobacteria, Bacilli, Sphingobacteria, and Flavobacteria, were also enriched from cultures with xylan or carboxymethyl cellulose as sole carbon sources. Numerous individual isolates could target diverse structural lignocellulose polysaccharides by expressing hydrolytic activities on crystalline or amorphous cellulose and xylan. Specific isolates showed increased potential for growth in lignin hydrolysates prepared from alkali pretreated agricultural wastes. The results suggest that Keri isolates represent a pool of effective lignocellulose degraders with significant potential for industrial applications in a lignocellulose biorefinery.
International Journal of Sediment Research, Mar 1, 2012
Acoustic classification systems and the Sediment Trend Analysis method were used to identify and ... more Acoustic classification systems and the Sediment Trend Analysis method were used to identify and map the bed diversity in a very shallow (<3.0m), coastal lagoon, Pappas lagoon, Western Greece. Analogue acoustic data, collected by means of a 100 kHz side scan sonar system, were digitized and classified into six acoustic classes using recently developed acoustic classification systems (SonarClass, TargAn). By comparing the acoustic classes to ground truth data consisting of sediment grain size and visual inspection of the lagoon-bed, it is demonstrated that the six acoustic classes correlate well with the predominant surface sediment types and vegetation. Thus the spatial distribution of the classes can be considered to represent the spatial pattern of the sedimentary assemblages of the lagoon. The grain size trend analysis identified three dominant sediment pathways and directional trends which could be related to the predominant wind direction, the sediment influx through the inlets and the sediment supply from a small stream in the southern part of the lagoon. The integration of acoustic and sedimentological data together with advanced data processing systems leads to a better understanding of the sedimentary, morphological and biological processes in a shallow lagoon in different spatial and temporal scales and will therefore be beneficial to both sedimentological and biotic-diversity studies.
ABSTRACT The present paper interprets the sedimentological, palaeontological and palynological da... more ABSTRACT The present paper interprets the sedimentological, palaeontological and palynological data, retrieved from a 21 m depth core from the Alikes Lagoon of Zakynthos Island, in order to reconstruct the depositional environments and palaeoclimatic evolution of the area, as well as to estimate the rate of sedimentation from a time period between 8540 and 3400 BP. Sediment analyses include grain size analysis – moment measurements, definition of total organic carbon (TOC) and total nitrogen (TN). The foraminiferal analysis along the core was based on 44 sediment samples. The reconstructed depositional environments correspond to those of a coastal lagoon (restricted – shallow) and lagoon margins, with a series of intercalating events where marine characteristics dominate, and are related to climatic conditions, to the change in the communication of the coastal lagoon with the open sea and events such as storms or tsunami. From 80 pollen taxa which were determined, 25 are arboreal, 41 non-arboreal and 14 local. Four local pollen assemblage zones were classified. Different rates of sedimentation were observed along the core, including one of 39.14 mm/y, between 7250 and 7110 BP, which is one of the highest that has been observed in the coastal areas of western Greece. This event coincides in age with a general change in the coastal zone of Ionian Sea, correlated with a shift in the rate of relative sea level rise and local tectonic activity.
Bulletin of the Geological Society of Greece, Jan 23, 2017
The study area is the Alikes wetland (an old salt pan) which is located in the northern part of Z... more The study area is the Alikes wetland (an old salt pan) which is located in the northern part of Zakynthos island. In the Alikes lagoon an exploratory borehole (GA-1) were drilled in a depth up to 21.20m. A total number of forty six (46) samples were analysed for their particle size, calcium carbonate and total organic carbon content. Moreover, bulk sample chemical analyses for major and trace elements were carried out on 12 samples, as well as mineralogical analysis for bulk, oriented and the clay fraction (<2 μm) were determined by powder X-Ray diffraction. The grain size characteristics, statistical parameters and TOC, for the Holocene analysed samples, suggest a coastal environment (restricted-shallow) with reduced salinity such as a lagoon margin and in a tidal flat and/or marsh particularly. Depositional environments and the source material affecting the geochemical signature indicating that that Al, Mg, K are mainly associated with the aluminosilicate fraction of the sediments analyzed, Fe and Ti consistent with detrital phases, while Ca, Si, P, and Mn showing different geochemical patterns.
The Klisova lagoon aquatic system belongs to the wetland of Messolonghi-Aetoliko-Klisova Lagoon C... more The Klisova lagoon aquatic system belongs to the wetland of Messolonghi-Aetoliko-Klisova Lagoon Complex, located in the western Greece and represents one of the most important Mediterranean lagoon systems, as it is protected by international conventions and is listed in the Natura 2000 European Network. Water physicochemical parameters such as pH, temperature, salinity, dissolved oxygen, nutrients definition, TOC, TN and bacteriological indicators (E.coli and Enterococcus spp.) were analyzed in a time period of 1 year monthly monitoring in five sampling sites along the lagoon. The geographical distribution of these parameters show a clear zonation and partition of the lagoon as the result of: (a) the discharging of poorly treated wastes into the lagoon of Mesolonghi city waste water treatment plant and (b) the interplay between sea water influence via the lagoon inlet and the fresh water inflow via lagoon's perimeter channels. The lagoon is characterized by seasonal hypoxic conditions, which are responsible for several ecological socks in the past including fish mortalities. The system is threatened by human interference and sedimentological processes such as the longshore drifting and siltation of the lagoon inlet. Measurements should immediately be taken in order to prevent further downgrading of the water quality.
... 97111. D. Frydas and H. Keupp, Biostratigraphical results in Late Neogene deposits of NW Cre... more ... 97111. D. Frydas and H. Keupp, Biostratigraphical results in Late Neogene deposits of NW Crete based on calcareous nannofossils, Berliner geowiss. Abh. ... 31 (1975), pp. 763777. HY Ling, Late Neogene silicoflagellates and ebridians from Leg 128, Sea of Japan. ...
This study presents the application of a simultaneous method for the determination of total organ... more This study presents the application of a simultaneous method for the determination of total organic carbon (TOC) and total nitrogen (TN) in marine sediments and soils, using a data set of 206 samples collected from coastal lagoonal/marine sedimentary environments and certified reference materials (CRMs). TOC and TN were determined using the high temperature (720˚C) catalytic (Pt/Al 2 O 3) oxidation method and the detection of TOC and TN was performed using an infrared or a chemiluminescence detector, respectively. Results from the abovementioned TOC method were compared with the results from the widely used Wakley-Black titration method, while TN results with these from elemental analysis. Analytical quality control experiments were performed using CRM samples. Method characteristics such as range of measurement, calibration, method detection limit (MDL), limit of quantification (LOQ), repeatability and reproducibility, were calculated. The precision and the accuracy of the methods are also discussed. Comparison of the two TOC methods of 206 data set yields a regression line of correlation coefficient with R 2 = 0.985. Additional different levels of TOC concentrations of low <1%, moderate 1-5% and high 5-40% level were examined indicating very good correlations. The lowest correlation coefficient was observed in low concentrations TOC<1% (R 2 0.825), mainly as a result of the limitation of titration method. The evaluation of TN results indicated that the catalytic oxidation method and the elemental analysishave a significant good correlation with R 2 = 0.977. The results of precision and accuracy, as well as the calculated MDL and LOQ show that this is a reliable method. Moreover, it requires a small amount of the analyzed sample and the total analysis time is 10 min. Therefore, it can be easily applied for the fast and precise simultaneous determination of TOC and TN in sediment and soil samples.
The Prokopos Lagoon is part of the Kotychi Strofilias National Wetlands Park, which is supervised... more The Prokopos Lagoon is part of the Kotychi Strofilias National Wetlands Park, which is supervised by the Ministry of Environment, Energy and Climate Change of Greece. The lagoon is situated at the northwestern coast of the Peloponnese and is protected by the Ramsar Convention. It is an important ecosystem with ecological services providing habitats for many plants and animals and essential goods and services for humans as well. No previous relevant studies for the wider wetland area are available, and given that lagoons are important ecosystems, their diachronic evolution should be under constant monitoring. Using remote sensing techniques in Geographic Information System (GIS) environment, alterations in critical parameters could be measured and applied for the protection of the area. The present study examines the spatiotemporal changes of the water extent of the Prokopos Lagoon, estimating landscape metrics and several morphometric parameters and indices related to the geomorphol...
Copper-based bactericides have appeared as a new tool in crop protection and offer an effective s... more Copper-based bactericides have appeared as a new tool in crop protection and offer an effective solution to combat bacterial resistance. In this work, two copper nanoparticle products that were previously synthesized and evaluated against major bacterial and fungal pathogens were tested on their ability to control the bacterial spot disease of tomato. Growth of Xanthomonas campestris pv. vesicatoria, the causal agent of the disease, was significantly suppressed by both nanoparticles, which had superior function compared to conventional commercial formulations of copper. X-ray fluorescence spectrometry measurements in tomato leaves revealed that bioavailability of copper is superior in the case of nanoparticles compared to conventional formulations and is dependent on synthesis rather than size. This is the first report correlating bioavailability of copper to nanoparticle efficacy.
&amp;lt;p&amp;gt;Benthic foraminiferal assemblages were analysed to determine their seaso... more &amp;lt;p&amp;gt;Benthic foraminiferal assemblages were analysed to determine their seasonal variation and evaluate the effects of environmental factors on their density, species composition and distribution, in the semi-enclosed Thermaikos Gulf, in the NW part of the Aegean Sea. Three major rivers, two minor ones and several ephemeral streams flow into the shallow Thermaikos basin, discharging annually tonnes of sediment, forming a submarine delta on the west part of the gulf and causing the constant occurrence of dissolved solids in the water column. During the high precipitation period (January-May), the fresh water intrusion extends to the major part of the gulf (surface salinities &amp;lt;25), while during the whole year more saline waters from the northern Aegean flow towards the northeast, entering the gulf.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Changes in the foraminiferal abundance and composition was explored during a twelve-month monitoring, compared to a multi-parameter environmental dataset (temperature, salinity, pH and nutrients), metal content and organic carbon. Sampling of the top 2cm of the surface sediment was carried out on a monthly basis (January-December 2016) at one station (S1), and at 5 stations (S1-S5) during winter (February), spring (April), summer (July) and autumn (October), located in Thessaloniki Bay (inner part of the Thermaikos Gulf). During late spring-summer (April to August), foraminiferal densities and relative percentages of the living specimens displayed the highest values, while high diversities (Shannon-Wiener index) were observed during winter. The different samples investigated seasonally present a variability, with respect to both abiotic parameters and the foraminiferal assemblage. The main part of the gulf (muddy bottom - max depth 23 m) is dominated mainly by &amp;lt;em&amp;gt;Bulimina&amp;lt;/em&amp;gt; spp., &amp;lt;em&amp;gt;Bolivina&amp;lt;/em&amp;gt; spp., &amp;lt;em&amp;gt;Uvigerina&amp;lt;/em&amp;gt; spp. and various species of agglutinated foraminifera, such as &amp;lt;em&amp;gt;Textularia&amp;lt;/em&amp;gt; &amp;lt;em&amp;gt;bocki&amp;lt;/em&amp;gt;, &amp;lt;em&amp;gt;Eggereloides&amp;lt;/em&amp;gt; &amp;lt;em&amp;gt;scaber&amp;lt;/em&amp;gt;, and &amp;lt;em&amp;gt;Reophax&amp;lt;/em&amp;gt; spp. Samples from the western part of the gulf (sandy bottom - max depth 3 m) were characterized by a more diversified assemblage also including miliolids and a variety of small, epiphytic rotaliid taxa.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The exceptional environmental conditions that prevail in the environments of the inner Thermaikos Gulf, are reflected in foraminiferal composition, making it an ideal laboratory for the study of the microfauna in response to a combination of stressful parameters in a natural physiochemically complex environment.&amp;lt;/p&amp;gt;
In this study, we present the findings of a sediment core retrieved from Klisova lagoon, Western ... more In this study, we present the findings of a sediment core retrieved from Klisova lagoon, Western Greece, an area with a long record of documented human presence. The recovered deposits were subjected to sedimentological, XRF, and micropaleontological analyses. For the last 4700 cal BP, the freshwater influx, the progradation of the Evinos river delta and related geomorphological changes control the environmental conditions in the lagoon. Considering the centennial temporal resolution of our analyses, small offsets of c.a. 50 years due to lack of regional reservoir correction do not considerably impact the reported radiocarbon ages. Prior to 4000 cal BP, a relatively shallow water depth, significant terrestrial/freshwater input and increased weathering in the lagoon area are inferred. Elemental proxies and increased dinoflagellate cyst and foraminiferal abundances, which indicate marine conditions with prominent freshwater influxes, point to the gradual deepening of the lagoon up to ...
Bulletin of the Geological Society of Greece, 2018
In order to estimate the palaeoflow direction of the submarine fans, deposited in the Internal Io... more In order to estimate the palaeoflow direction of the submarine fans, deposited in the Internal Ionian subbasin of the Pindos Foreland, fifty-one positions along the sub-basin were selected and measurements of palaeocurrents indicators such as flute and groove marks were taken. In the studied area the main palaeoflow direction of turbidites was axial, from south to north in the southern part, and from north to south in the northern part. A minor westward palaeoflow direction is also present. These palaeoflow directions were influenced mainly by the regional tectonic activity, such as internal thrusting (Gavrovo Thrust) and differential activity of the Pindos Thrust which subdivided Pindos foreland into narrow linear sub-basins.
In this study, soil and aquatic sediments were sampled in the Aetoliko Lagoon and its catchment a... more In this study, soil and aquatic sediments were sampled in the Aetoliko Lagoon and its catchment area, which is exclusively dominated by olive orchards. For the first time in Greece, soil as well as sediments samples of one coherent protected aquatic ecosystem were directly compared. In order to determine the influence that the usage of copper-based fungicides have on the lagoon sediments and on the soils of the surrounding area, twenty five (25) soil samples from different olive orchards that are bordering the water body and ten (10) sediment samples from the bottom of the lagoon were taken. The samples were analyzed for total copper content (total digestion) and extractable copper (diethylenetriaminepenta acetic acid, DTPA, extraction method). Furthermore, soil/sedimentological and geochemical analyses such as pH, grain size, total organic carbon, total sulfur, total nitrogen, and calcium carbonate content were carried out. The results show that the total copper in soils ranges fro...
Many hirundine species construct their nests by carrying mud particles from adjacent areas. This ... more Many hirundine species construct their nests by carrying mud particles from adjacent areas. This study aimed to investigate for the first time the materials that mud-nesting hirundines choose for nest construction from a mineralogical and sedimentological perspective. For this purpose, we sampled nests of three sympatric species, namely the Barn Swallow (Hirundo rustica), the Red-rumped Swallow (Cecropis daurica) and the House Martin (Delichon urbicum), from southeastern Europe. Our results showed that all species tend to use clay minerals as a cement and especially smectite and illite and if these minerals are not present in the adjacent area, they use halloysite, kaolinite or chlorite. The amounts of clay minerals in the nests are generally low indicating that the studied species can accurately identify the properties of the nesting materials. Most of the non clay minerals that they use are the common, easily accessible colourless or white minerals with low specific gravity values such as quartz, feldspars and calcite. Grain size distribution analysis revealed that the amount of clay sized grains in the mud nests of all three species is relatively low, while the amount of larger grain particles decreases when the size of the non clay minerals is small. The Red-rumped Swallow showed an increasing preference for larger grain size particles and quartz, the Barn Swallow for finer grain size particles and calcite, and the preferences of the House Martin are in between the other two species. The three hirundine species present different nest building strategies and depending on the nest architecture, each of them seems to show preference for specific minerals and specific grain sizes. Swallows and martins (Hirundinidae) are small, aerial insectivorous passerines that nest either in excavated holes in banks or in cups built mainly of mud and organic material 1. Five migratory members of this family breed in Southern Europe, i.e. the Sand Martin (Riparia riparia), the Crag Martin (Ptyonoprogne rupestris), the House Martin (Delichon urbicum), the Barn Swallow (Hirundo rustica) and the Red-rumped Swallow (Cecropis daurica). The last three species build mud nests in sheltered locations, principally in rural areas and human settlements, though the nest style differs among the three species 1. House Martins are generally colonial breeders, closely associated with buildings, but large colonies can also be found on cliffs. They build an enclosed mud nest with the entrance at the top, usually attached to eaves or overhangs (Fig. 1). Red-rumped Swallows are generally solitary and breed mainly in mountainous areas with cliffs and coastal areas but also in towns and villages. They build a completely closed semi-spherical nest of mud with a tunnel entrance, under overhangs, bridges, eaves or in caves (Fig. 1). Contrary, Barn Swallows, a typical farmland species, build open-topped mud cups reinforced with straws and plant material (Fig. 1), usually adhered to beams, walls or ledges of houses, in barns or in sheds 2,3. Mud nesting hirundines, such as the House Martins and the Red-rumped Swallows, invest enormous effort in nest construction, as they might need to carry more than 1000 pellets of wet mud within a period of a couple of weeks 4-6 .
During the last few decades, X-ray attenuation systems have been established as standard techniqu... more During the last few decades, X-ray attenuation systems have been established as standard techniques in geosciences and as excellent scientific tools for the analysis of sedimentary facies and structures. In the present study, we use two non-destructive and high-resolution systems (computed tomography, X-ray fluorescence) to address all sedimentological facies and structural characteristics on a 6 m long, partly laminated sediment record, from Vouliagmeni lake, located at the eastern part of the Corinth Gulf, Greece. Vouliagmeni lake is the deepest coastal lake in Greece, and its location is of great importance since it is located in one of the most tectonically active regions in the world. The chronological framework of the retrieved sediment sequence spans the last 12,000 years, with alternations of laminated and non-laminated sections. The annual accumulation of the laminated sequences was determined through the radionuclide concentration of 14 samples. Scanning tomography was performed with a medical CT scanner and a µCT scanner, aiming to compare the potentials and variations of both methods. Lamination boundaries, event layers (turbidites) and sediment deformations were distinguished through processing the extracted 3D rendered volumes, after applying ranges depending on Hounsfield (HU) values. Microscopic analysis revealed three main layer types in the varve sequences that were examined, attributing to summer/spring, autumn and winter deposits. Statistical analysis of the elemental composition, magnetic susceptibility (MS) measurements and HU values revealed three clusters/facies, reflecting climatic and in-lake hydrological changes. Cluster A emulates sedimentation during arid conditions, while Cluster B reflects humid conditions with increased precipitation and erosion. Cluster C represents sequences with homogenous Ca-rich sediment. Our proposed workflow highlights the possible correlation between the non-destructive variables that were measured, but also the variations and applications of each method and software used during this study.
Multidisciplinary studies in coastal systems of the eastern Mediterranean region have proven to b... more Multidisciplinary studies in coastal systems of the eastern Mediterranean region have proven to be excellent tools in understanding paleoenvironmental, paleoecological, and paleoclimatic changes that took place during the Holocene period, and how these changes interacted with urban development and growth. This paper presents sedimentological, high-resolution x-ray fluorescence (XRF scanning), micropaleontological, and x-ray diffraction (XRD) data from three shallow sediment cores that were retrieved from Aliki (ancient Siphai or Tipha) salt pond. The study area is located in a unique, highly tectonic geographical region, at the northeast part of the Gulf of Corinth in Greece. Beachrock deposits that form a barrier between the salt pond and the marine environment seem to play an important role in the evolution of the area. The chronological framework was set at around 3100 cal. BP by four 14 C radiocarbon dates, and the evolutionary model that was established indicates four different changes taking place during this period at the study area. From around 3100 to 1600 cal. BP, a transition from a closed to an open lagoonal environment was identified, interrupted by a fluvial terrestrial deposit at around 2500 cal. BP. A shift toward a closed lagoonal system at around 1600 cal. BP and the establishment of a salt pond environment seem to correlate with tectonic activity. The study provides important information about the evolution of coastal landscape in such a tectonic active region and points the interaction between regional human activity and climatic changes during the late-Holocene period.
In the present study we present preliminary results of Zakynthos Alikes lagoon, which is one of t... more In the present study we present preliminary results of Zakynthos Alikes lagoon, which is one of the most seismically active regions of Greece. In order to estimate-interpret the Holocene evolution of the area and to reconstruct the palaeonvironmental changes, we based on the data of a 21 m sediment core. Sediment types, structure, colour, as well as contact depths and bed characteristics, were recorded in the field. Standarised sedimentological analysis were carried out, on 46 samples including grain size analysis, calculation of moment measures, and micro-and molluscan fossils of 17 selected samples. Moreover, radiocarbon age determinations have been made on individual Cardium shells from two horizons and whole-core Magnetic Susceptibility (MS) measurements were taken. The interpretation of depositional environments suggests a coastal environment (restricted-shallow) with reduced salinity such as a lagoon margin and in a tidal flat and/or marsh particularly. The maximum age of the study sediments is about 8500 BP. The rate of sedimentation between 8280 BP and 5590 BP was 5.3 mm/yr and between 5590 BP and modern times 1.03 mm/yr. The rate of sedimentation was higher until mid-Holocene while decrease after to 1.03 mm/yr, results which are similar to other coastal areas of western Greece.
Bacterial systems have gained wide attention for depolymerization of lignocellulosic biomass, due... more Bacterial systems have gained wide attention for depolymerization of lignocellulosic biomass, due to their high functional diversity and adaptability. To achieve the full microbial exploitation of lignocellulosic residues and the cost-effective production of bioproducts within a biorefinery, multiple metabolic pathways and enzymes of various specificities are required. In this work, highly diverse aerobic, mesophilic bacteria enriched from Keri Lake, a pristine marsh of increased biomass degradation and natural underground oil leaks, were explored for their metabolic versatility and enzymatic potential towards lignocellulosic substrates. A high number of Pseudomonas species, obtained from enrichment cultures where organosolv lignin served as the sole carbon and energy source, were able to assimilate a range of lignin-associated aromatic compounds. Comparatively more complex bacterial consortia, including members of Actinobacteria, Proteobacteria, Bacilli, Sphingobacteria, and Flavobacteria, were also enriched from cultures with xylan or carboxymethyl cellulose as sole carbon sources. Numerous individual isolates could target diverse structural lignocellulose polysaccharides by expressing hydrolytic activities on crystalline or amorphous cellulose and xylan. Specific isolates showed increased potential for growth in lignin hydrolysates prepared from alkali pretreated agricultural wastes. The results suggest that Keri isolates represent a pool of effective lignocellulose degraders with significant potential for industrial applications in a lignocellulose biorefinery.
International Journal of Sediment Research, Mar 1, 2012
Acoustic classification systems and the Sediment Trend Analysis method were used to identify and ... more Acoustic classification systems and the Sediment Trend Analysis method were used to identify and map the bed diversity in a very shallow (<3.0m), coastal lagoon, Pappas lagoon, Western Greece. Analogue acoustic data, collected by means of a 100 kHz side scan sonar system, were digitized and classified into six acoustic classes using recently developed acoustic classification systems (SonarClass, TargAn). By comparing the acoustic classes to ground truth data consisting of sediment grain size and visual inspection of the lagoon-bed, it is demonstrated that the six acoustic classes correlate well with the predominant surface sediment types and vegetation. Thus the spatial distribution of the classes can be considered to represent the spatial pattern of the sedimentary assemblages of the lagoon. The grain size trend analysis identified three dominant sediment pathways and directional trends which could be related to the predominant wind direction, the sediment influx through the inlets and the sediment supply from a small stream in the southern part of the lagoon. The integration of acoustic and sedimentological data together with advanced data processing systems leads to a better understanding of the sedimentary, morphological and biological processes in a shallow lagoon in different spatial and temporal scales and will therefore be beneficial to both sedimentological and biotic-diversity studies.
ABSTRACT The present paper interprets the sedimentological, palaeontological and palynological da... more ABSTRACT The present paper interprets the sedimentological, palaeontological and palynological data, retrieved from a 21 m depth core from the Alikes Lagoon of Zakynthos Island, in order to reconstruct the depositional environments and palaeoclimatic evolution of the area, as well as to estimate the rate of sedimentation from a time period between 8540 and 3400 BP. Sediment analyses include grain size analysis – moment measurements, definition of total organic carbon (TOC) and total nitrogen (TN). The foraminiferal analysis along the core was based on 44 sediment samples. The reconstructed depositional environments correspond to those of a coastal lagoon (restricted – shallow) and lagoon margins, with a series of intercalating events where marine characteristics dominate, and are related to climatic conditions, to the change in the communication of the coastal lagoon with the open sea and events such as storms or tsunami. From 80 pollen taxa which were determined, 25 are arboreal, 41 non-arboreal and 14 local. Four local pollen assemblage zones were classified. Different rates of sedimentation were observed along the core, including one of 39.14 mm/y, between 7250 and 7110 BP, which is one of the highest that has been observed in the coastal areas of western Greece. This event coincides in age with a general change in the coastal zone of Ionian Sea, correlated with a shift in the rate of relative sea level rise and local tectonic activity.
Bulletin of the Geological Society of Greece, Jan 23, 2017
The study area is the Alikes wetland (an old salt pan) which is located in the northern part of Z... more The study area is the Alikes wetland (an old salt pan) which is located in the northern part of Zakynthos island. In the Alikes lagoon an exploratory borehole (GA-1) were drilled in a depth up to 21.20m. A total number of forty six (46) samples were analysed for their particle size, calcium carbonate and total organic carbon content. Moreover, bulk sample chemical analyses for major and trace elements were carried out on 12 samples, as well as mineralogical analysis for bulk, oriented and the clay fraction (<2 μm) were determined by powder X-Ray diffraction. The grain size characteristics, statistical parameters and TOC, for the Holocene analysed samples, suggest a coastal environment (restricted-shallow) with reduced salinity such as a lagoon margin and in a tidal flat and/or marsh particularly. Depositional environments and the source material affecting the geochemical signature indicating that that Al, Mg, K are mainly associated with the aluminosilicate fraction of the sediments analyzed, Fe and Ti consistent with detrital phases, while Ca, Si, P, and Mn showing different geochemical patterns.
The Klisova lagoon aquatic system belongs to the wetland of Messolonghi-Aetoliko-Klisova Lagoon C... more The Klisova lagoon aquatic system belongs to the wetland of Messolonghi-Aetoliko-Klisova Lagoon Complex, located in the western Greece and represents one of the most important Mediterranean lagoon systems, as it is protected by international conventions and is listed in the Natura 2000 European Network. Water physicochemical parameters such as pH, temperature, salinity, dissolved oxygen, nutrients definition, TOC, TN and bacteriological indicators (E.coli and Enterococcus spp.) were analyzed in a time period of 1 year monthly monitoring in five sampling sites along the lagoon. The geographical distribution of these parameters show a clear zonation and partition of the lagoon as the result of: (a) the discharging of poorly treated wastes into the lagoon of Mesolonghi city waste water treatment plant and (b) the interplay between sea water influence via the lagoon inlet and the fresh water inflow via lagoon's perimeter channels. The lagoon is characterized by seasonal hypoxic conditions, which are responsible for several ecological socks in the past including fish mortalities. The system is threatened by human interference and sedimentological processes such as the longshore drifting and siltation of the lagoon inlet. Measurements should immediately be taken in order to prevent further downgrading of the water quality.
... 97111. D. Frydas and H. Keupp, Biostratigraphical results in Late Neogene deposits of NW Cre... more ... 97111. D. Frydas and H. Keupp, Biostratigraphical results in Late Neogene deposits of NW Crete based on calcareous nannofossils, Berliner geowiss. Abh. ... 31 (1975), pp. 763777. HY Ling, Late Neogene silicoflagellates and ebridians from Leg 128, Sea of Japan. ...
This study presents the application of a simultaneous method for the determination of total organ... more This study presents the application of a simultaneous method for the determination of total organic carbon (TOC) and total nitrogen (TN) in marine sediments and soils, using a data set of 206 samples collected from coastal lagoonal/marine sedimentary environments and certified reference materials (CRMs). TOC and TN were determined using the high temperature (720˚C) catalytic (Pt/Al 2 O 3) oxidation method and the detection of TOC and TN was performed using an infrared or a chemiluminescence detector, respectively. Results from the abovementioned TOC method were compared with the results from the widely used Wakley-Black titration method, while TN results with these from elemental analysis. Analytical quality control experiments were performed using CRM samples. Method characteristics such as range of measurement, calibration, method detection limit (MDL), limit of quantification (LOQ), repeatability and reproducibility, were calculated. The precision and the accuracy of the methods are also discussed. Comparison of the two TOC methods of 206 data set yields a regression line of correlation coefficient with R 2 = 0.985. Additional different levels of TOC concentrations of low <1%, moderate 1-5% and high 5-40% level were examined indicating very good correlations. The lowest correlation coefficient was observed in low concentrations TOC<1% (R 2 0.825), mainly as a result of the limitation of titration method. The evaluation of TN results indicated that the catalytic oxidation method and the elemental analysishave a significant good correlation with R 2 = 0.977. The results of precision and accuracy, as well as the calculated MDL and LOQ show that this is a reliable method. Moreover, it requires a small amount of the analyzed sample and the total analysis time is 10 min. Therefore, it can be easily applied for the fast and precise simultaneous determination of TOC and TN in sediment and soil samples.
The Prokopos Lagoon is part of the Kotychi Strofilias National Wetlands Park, which is supervised... more The Prokopos Lagoon is part of the Kotychi Strofilias National Wetlands Park, which is supervised by the Ministry of Environment, Energy and Climate Change of Greece. The lagoon is situated at the northwestern coast of the Peloponnese and is protected by the Ramsar Convention. It is an important ecosystem with ecological services providing habitats for many plants and animals and essential goods and services for humans as well. No previous relevant studies for the wider wetland area are available, and given that lagoons are important ecosystems, their diachronic evolution should be under constant monitoring. Using remote sensing techniques in Geographic Information System (GIS) environment, alterations in critical parameters could be measured and applied for the protection of the area. The present study examines the spatiotemporal changes of the water extent of the Prokopos Lagoon, estimating landscape metrics and several morphometric parameters and indices related to the geomorphol...
Copper-based bactericides have appeared as a new tool in crop protection and offer an effective s... more Copper-based bactericides have appeared as a new tool in crop protection and offer an effective solution to combat bacterial resistance. In this work, two copper nanoparticle products that were previously synthesized and evaluated against major bacterial and fungal pathogens were tested on their ability to control the bacterial spot disease of tomato. Growth of Xanthomonas campestris pv. vesicatoria, the causal agent of the disease, was significantly suppressed by both nanoparticles, which had superior function compared to conventional commercial formulations of copper. X-ray fluorescence spectrometry measurements in tomato leaves revealed that bioavailability of copper is superior in the case of nanoparticles compared to conventional formulations and is dependent on synthesis rather than size. This is the first report correlating bioavailability of copper to nanoparticle efficacy.
&amp;lt;p&amp;gt;Benthic foraminiferal assemblages were analysed to determine their seaso... more &amp;lt;p&amp;gt;Benthic foraminiferal assemblages were analysed to determine their seasonal variation and evaluate the effects of environmental factors on their density, species composition and distribution, in the semi-enclosed Thermaikos Gulf, in the NW part of the Aegean Sea. Three major rivers, two minor ones and several ephemeral streams flow into the shallow Thermaikos basin, discharging annually tonnes of sediment, forming a submarine delta on the west part of the gulf and causing the constant occurrence of dissolved solids in the water column. During the high precipitation period (January-May), the fresh water intrusion extends to the major part of the gulf (surface salinities &amp;lt;25), while during the whole year more saline waters from the northern Aegean flow towards the northeast, entering the gulf.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Changes in the foraminiferal abundance and composition was explored during a twelve-month monitoring, compared to a multi-parameter environmental dataset (temperature, salinity, pH and nutrients), metal content and organic carbon. Sampling of the top 2cm of the surface sediment was carried out on a monthly basis (January-December 2016) at one station (S1), and at 5 stations (S1-S5) during winter (February), spring (April), summer (July) and autumn (October), located in Thessaloniki Bay (inner part of the Thermaikos Gulf). During late spring-summer (April to August), foraminiferal densities and relative percentages of the living specimens displayed the highest values, while high diversities (Shannon-Wiener index) were observed during winter. The different samples investigated seasonally present a variability, with respect to both abiotic parameters and the foraminiferal assemblage. The main part of the gulf (muddy bottom - max depth 23 m) is dominated mainly by &amp;lt;em&amp;gt;Bulimina&amp;lt;/em&amp;gt; spp., &amp;lt;em&amp;gt;Bolivina&amp;lt;/em&amp;gt; spp., &amp;lt;em&amp;gt;Uvigerina&amp;lt;/em&amp;gt; spp. and various species of agglutinated foraminifera, such as &amp;lt;em&amp;gt;Textularia&amp;lt;/em&amp;gt; &amp;lt;em&amp;gt;bocki&amp;lt;/em&amp;gt;, &amp;lt;em&amp;gt;Eggereloides&amp;lt;/em&amp;gt; &amp;lt;em&amp;gt;scaber&amp;lt;/em&amp;gt;, and &amp;lt;em&amp;gt;Reophax&amp;lt;/em&amp;gt; spp. Samples from the western part of the gulf (sandy bottom - max depth 3 m) were characterized by a more diversified assemblage also including miliolids and a variety of small, epiphytic rotaliid taxa.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The exceptional environmental conditions that prevail in the environments of the inner Thermaikos Gulf, are reflected in foraminiferal composition, making it an ideal laboratory for the study of the microfauna in response to a combination of stressful parameters in a natural physiochemically complex environment.&amp;lt;/p&amp;gt;
In this study, we present the findings of a sediment core retrieved from Klisova lagoon, Western ... more In this study, we present the findings of a sediment core retrieved from Klisova lagoon, Western Greece, an area with a long record of documented human presence. The recovered deposits were subjected to sedimentological, XRF, and micropaleontological analyses. For the last 4700 cal BP, the freshwater influx, the progradation of the Evinos river delta and related geomorphological changes control the environmental conditions in the lagoon. Considering the centennial temporal resolution of our analyses, small offsets of c.a. 50 years due to lack of regional reservoir correction do not considerably impact the reported radiocarbon ages. Prior to 4000 cal BP, a relatively shallow water depth, significant terrestrial/freshwater input and increased weathering in the lagoon area are inferred. Elemental proxies and increased dinoflagellate cyst and foraminiferal abundances, which indicate marine conditions with prominent freshwater influxes, point to the gradual deepening of the lagoon up to ...
Bulletin of the Geological Society of Greece, 2018
In order to estimate the palaeoflow direction of the submarine fans, deposited in the Internal Io... more In order to estimate the palaeoflow direction of the submarine fans, deposited in the Internal Ionian subbasin of the Pindos Foreland, fifty-one positions along the sub-basin were selected and measurements of palaeocurrents indicators such as flute and groove marks were taken. In the studied area the main palaeoflow direction of turbidites was axial, from south to north in the southern part, and from north to south in the northern part. A minor westward palaeoflow direction is also present. These palaeoflow directions were influenced mainly by the regional tectonic activity, such as internal thrusting (Gavrovo Thrust) and differential activity of the Pindos Thrust which subdivided Pindos foreland into narrow linear sub-basins.
In this study, soil and aquatic sediments were sampled in the Aetoliko Lagoon and its catchment a... more In this study, soil and aquatic sediments were sampled in the Aetoliko Lagoon and its catchment area, which is exclusively dominated by olive orchards. For the first time in Greece, soil as well as sediments samples of one coherent protected aquatic ecosystem were directly compared. In order to determine the influence that the usage of copper-based fungicides have on the lagoon sediments and on the soils of the surrounding area, twenty five (25) soil samples from different olive orchards that are bordering the water body and ten (10) sediment samples from the bottom of the lagoon were taken. The samples were analyzed for total copper content (total digestion) and extractable copper (diethylenetriaminepenta acetic acid, DTPA, extraction method). Furthermore, soil/sedimentological and geochemical analyses such as pH, grain size, total organic carbon, total sulfur, total nitrogen, and calcium carbonate content were carried out. The results show that the total copper in soils ranges fro...
The conference is a collaborative effort among members of the PELOPS (Past Environments and Lands... more The conference is a collaborative effort among members of the PELOPS (Past Environments and Landscapes of Peloponnesian Societies) group, which is an interdisciplinary group of scholars with an ongoing engagement in human-environment interaction in the Peloponnese from archaeology, history, environmental and climate reconstructions.
The primary aim of the conference is to make a contribution to the ongoing debate concerning the form and content of interdisciplinary research on human-environment dynamics in past societies from prehistory to Late Antiquity. The conference will be an arena for innovative ideas, integrated methods and lessons learnt from current interdisciplinary projects in the Peloponnese and beyond. In answer to the open call for more collaborative research efforts, the conference will host 17 lectures by members of the PELOPS group and invited speakers, presenting well integrated accounts of human-environment interactions in past societies.
The conference will open on Thursday, 6 April, 2017, 7 pm at the Acropolis museum, with a lecture by Michael GIVEN (University of Glasgow), ‘Conviviality of the land: towards a new academic ecology’, followed by a welcome reception at the Swedish Institute at Athens.
The conference will thereafter take place at the American School of Classical Studies at Athens, 7-8 April, 9 am-18 pm.
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Papers by Pavlos Avramidis
The primary aim of the conference is to make a contribution to the ongoing debate concerning the form and content of interdisciplinary research on human-environment dynamics in past societies from prehistory to Late Antiquity. The conference will be an arena for innovative ideas, integrated methods and lessons learnt from current interdisciplinary projects in the Peloponnese and beyond. In answer to the open call for more collaborative research efforts, the conference will host 17 lectures by members of the PELOPS group and invited speakers, presenting well integrated accounts of human-environment interactions in past societies.
The conference will open on Thursday, 6 April, 2017, 7 pm at the Acropolis museum, with a lecture by Michael GIVEN (University of Glasgow), ‘Conviviality of the land: towards a new academic ecology’, followed by a welcome reception at the Swedish Institute at Athens.
The conference will thereafter take place at the American School of Classical Studies at Athens, 7-8 April, 9 am-18 pm.