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.
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.
... 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. ...
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.
<p>Benthic foraminiferal assemblages were analysed to determine their seaso... more <p>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 <25), while during the whole year more saline waters from the northern Aegean flow towards the northeast, entering the gulf.</p><p>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 <em>Bulimina</em> spp., <em>Bolivina</em> spp., <em>Uvigerina</em> spp. and various species of agglutinated foraminifera, such as <em>Textularia</em> <em>bocki</em>, <em>Eggereloides</em> <em>scaber</em>, and <em>Reophax</em> 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.</p><p>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.</p>
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...
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.
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.
... 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. ...
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.
<p>Benthic foraminiferal assemblages were analysed to determine their seaso... more <p>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 <25), while during the whole year more saline waters from the northern Aegean flow towards the northeast, entering the gulf.</p><p>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 <em>Bulimina</em> spp., <em>Bolivina</em> spp., <em>Uvigerina</em> spp. and various species of agglutinated foraminifera, such as <em>Textularia</em> <em>bocki</em>, <em>Eggereloides</em> <em>scaber</em>, and <em>Reophax</em> 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.</p><p>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.</p>
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.