Composition and Distribution of Recent Marine Ostracod Assemblages in the Bottom Sediments of Central Aegean Sea (SE Andros Island, Greece)

2012 ◽  
Vol 97 (4) ◽  
pp. 276-300 ◽  
Author(s):  
Theodora Tsourou
2004 ◽  
Vol 5 (1) ◽  
pp. 43
Author(s):  
K.G. PEHLIVANOGLOU ◽  
G. TRONTSIOS ◽  
A. TSIRAMBIDES

The Thermaikos Gulf constitutes the NW part of the North Aegean Sea and is limited eastward from the Chalkidiki Peninsula and westward from the Pieria Prefecture. Its plateau covers an area of 3,500 km2. The mechanisms responsible for the grain size distribution into the Gulf, the clay mineralogy and the chemistry of some bottom sediments from the outer Thermaikos Gulf, are examined. Source mixing during transportation, flocculation, differential settling processes and organic matter appear to be the main mechanisms for the distribution of clay minerals in shallow waters. All grain size fractions studied present a wide range of values confirming the extreme variations of the discharged load and the variability in marine processes. Plagioclases predominate over K-feldspars, while quartz is the most abundant mineral present. In addition, micas, chlorites, amphiboles and pyroxenes exist as primary and/or accessory minerals in all samples. Among clay minerals, illite predominates over smectite and smectite over chlorite (+ kaolinite). The ordered interstratified phase of I/S, with 30-35% S layers, is present in the 2-0.25µm fraction. The randomly interstratified phase of I/S, with 50% S layers, is present in the <0.25& micro; m fraction. On average the clay mineral content of the studied samples is: 48% I, 23% S, 17% Ch (+K) and 12% others for the 2-0.25µm fraction and 50% I, 30% S and 20% Ch (+K) for the <0.25 µm fraction. All these minerals are the weathering products of the rocks from the drainage basins of the rivers flowing into the Gulf, as well as of the Neogene and Quaternary unconsolidated sediments of the surrounding coasts. The terrigenous input, the water mass circulation and, to a lesser extent, the quality of the discharged material and the differential settling of grains, control the grain size distribution within the outer Thermaikos Gulf. The chemical composition of the analysed samples is generally in agreement with their mineral composition and signifies their terrigenous origin presenting discretely clastic character.


Diversity ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 232 ◽  
Author(s):  
Elias Polemis ◽  
Vassiliki Fryssouli ◽  
Vassileios Daskalopoulos ◽  
Georgios I. Zervakis

Alluvial forests dominated by black alder (Alnus glutinosa) are widespread in Europe along river banks and watercourses forming a habitat of renowned ecological/conservation importance. Despite the considerable interest this habitat has attracted in terms of the associated fungal diversity, very few pertinent data are available from the eastern Mediterranean. Andros island (Aegean Sea, Greece) hosts the southernmost population of A. glutinosa in the Balkan Peninsula; such stands have been systematically inventoried for several years in respect to macrofungi. In total, 187 specimens were collected and studied by examining morphoanatomic features and by evaluating (when necessary) the outcome of sequencing the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA) to elucidate their identity and obtain an insight into phylogenetic relationships. As a result, 106 species were recorded, 92 are saprotrophic and 14 form ectomycorrhizae (ECM) with alders. Twenty-one species are first national records, while 68 other species are reported for the first time from this habitat in Greece. Several findings of particular interest due to their rarity, ecological preferences and/or taxonomic status are presented in detail and discussed, e.g., six Alnicola taxa, Cortinarius americanus, Lactarius obscuratus, Paxillus olivellus and Russula pumila (among the ECMs), and the saprotrophs Entoloma uranochroum, Gymnopilus arenophilus, Hyphoderma nemorale, Lepiota ochraceofulva, Phanerochaete livescens and Psathyrella hellebosensis.


2003 ◽  
Vol 22 (1) ◽  
pp. 107-111 ◽  
Author(s):  
M. V. Triantaphyllou ◽  
M. D. Dimiza

Abstract. Living coccolithophores were collected from eight stations along a transect in the gulf of Korthi (southeastern Andros island, Aegean Sea, Eastern Mediterranean) in August 2001. Samples were collected from 0–120 m water depth to determine the cell density, the species composition and the biogeographical (spatial and vertical) distribution of the coccolithophore biocommunities in coastal marine ecosystems. The studies revealed an impressive heterococcolith–holococcolith combination coccosphere (SEM micrograph) involving the species Algirosphaera robusta and Sphaerocalyptra quadridentata. In addition, a second association was observed by light microscopy. This discovery verifies the suggestions of Kamptner (1941) and provides strong proof on the assignment of these two ‘species’ in a common life cycle, increasing significantly our knowledge of life-cycle pairings ecology.


2005 ◽  
Vol 48 (4) ◽  
pp. 279-302 ◽  
Author(s):  
Maria V. Triantaphyllou ◽  
Theodora Tsourou ◽  
Olga Koukousioura ◽  
Michael D. Dermitzakis

Author(s):  
Elvira A. Zinnatova, Larisa A. Frolova ◽  
Larisa A. Frolova

The Northern lakes are good objects for paleoclimatic reconstructions. One of the sources of information about changes in the ecosystems of lakes are diatoms. The study of diatom complexes revealed 133 taxa belonging to 49 genera, 24 families, 13 orders and 3 classes in the bottom sediments of the thermokarst lake of the Pechora Delta. Dominated by the Holarctic representatives of benthic and fouling organisms giving preference to the alkaline environmental conditions.


Author(s):  
Angelina E. Shatalova ◽  
Uriy A. Kublitsky ◽  
Dmitry A. Subetto ◽  
Anna V. Ludikova ◽  
Alar Rosentau ◽  
...  

The study of paleogeography of lakes is an actual and important direction in modern science. As part of the study of lakes in the North-West of the Karelian Isthmus, this analysis will establish the dynamics of salinity of objects, which will allow to reconstruct changes in the level of the Baltic Sea in the Holocene.


Author(s):  
O. A. Lipatnikova

The study of heavy metal speciation in bottom sediments of the Vyshnevolotsky water reservoir is presented in this paper. Sequential selective procedure was used to determine the heavy metal speciation in bottom sediments and thermodynamic calculation — to determine ones in interstitial water. It has been shown that Mn are mainly presented in exchangeable and carbonate forms; for Fe, Zn, Pb и Co the forms are related to iron and manganese hydroxides is played an important role; and Cu and Ni are mainly associated with organic matter. In interstitial waters the main forms of heavy metal speciation are free ions for Zn, Ni, Co and Cd, carbonate complexes for Pb, fulvate complexes for Cu. Effects of particle size and organic matter content in sediments on distribution of mobile and potentially mobile forms of toxic elements have been revealed.


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