Vertical zonation of testate amoebae in the Elatia Mires, northern Greece : palaeoecological evidence for a wetland response to recent climate change or autogenic processes?

The Elatia Mires of northern Greece are unique ecosystems of high conservation value. The mires are climatically marginal and may be sensitive to changing hydroclimate, while northern Greece has experienced a significant increase in aridity since the late twentieth century. To investigate the impact of recent climatic change on the hydrology of the mires, the palaeoecological record was investigated from three near-surface monoliths extracted from two sites. Testate amoebae were analysed as sensitive indicators of hydrology. Results were interpreted using transfer function models to provide quantitative reconstructions of changing water table depth and pH. AMS radiocarbon dates and 210Pb suggest the peats were deposited within the last c. 50 years, but do not allow a secure chronology to be established. Results from all three profiles show a distinct shift towards a more xerophilic community particularly noted by increases in Euglypha species. Transfer function results infer a distinct lowering of water tables in this period. A hydrological response to recent climate change is a tenable hypothesis to explain this change; however other possible explanations include selective test decay, vertical zonation of living amoebae, ombrotrophication and local hydrological change. It is suggested that a peatland response to climatic change is the most probable hypothesis, showing the sensitivity of marginal peatlands to recent climatic change

The so called ‘Herodotus Springs’ at ‘Keri Lake’ in Zakynthos Island western Greece:A palaeoenvironmental and palaeoecological approach

In the present study the palaeoenvironmental setting of the coastal mire/swamp zone called ‘Keri Lake’, on Zakynthos Island, west Greece is presented. The mire/swamp area is famous for the asphalt-pitch seepages named as ‘Herodotus-springs’. In order to interpret the Holocene evolution of the area, samples from four 7 m long vibracores were analyzed for their total organic carbon, total nitrogen and sulfur contents, as well as for their micro- and macro-fauna. The chronological framework of this study was based on three 14C ages, while the age depth model and the sedimentation rate were estimated applying OxCal software. The age depth model indicates that the cores cover the period from the middle Holocene to present, with a mean sedimentation rate of 1 mm/yr. Before 4000 BP large part of the area inundated by the sea while after 4000 yrs BP the ecosystem changed to a high marsh and gradually to a fen environment, where peat accumulated under telmatic to limnotelmatic conditions. The trends and the ratios of the geochemical markers TOC, TN and TS clearly reflect the palaeoenvironmental change from terrestrial to fen depositional environments. The results show that during the middle Holocene the Herodotus Lake was influenced by sudden sea water inundation events, possibly as a result of high waves or storm events, while since the late Holocene the setting is that of a brackish coastal fen, where peat accumulates, under the significant inflow of fresh water that originates from the karstic systems of the catchment area

Influence of Geological Conditions during Peat Accumulation on Trace Element Affinities and Their Behavior during Peat Combustion

7 páginas, 2 figuras, 7 tablas.The Philippi peat, NE Greece, constitutes one of the largest fossil fuel deposits in the Balkans and its potential use for power generation cannot be ruled out in the future. In this study, the concentrations of 43 trace elements (Ag, As, Ba, Be, Bi, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Ga, Gd, Ge, Hf, Ho, La, Li, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Sb, Sc, Sm, Sn, Sr, Ta, Tb, Th, U, V, W, Y, Yb, Zn, and Zr) in the 550 °C peat ashes are determined and related to the concentrations in the bulk peat, to evaluate the behavior of each element during combustion. Mineralogical analysis of the chemically oxidized peat samples revealed that clay minerals, feldspars, quartz, gypsum, and calcite are the dominant mineral phases. The behavior of the trace elements during combustion depends significantly on this mineral composition that, in turn, depends on the depositional conditions during peat accumulation.This work was funded through the Greek-Spanish Bilateral Agreement for Scientific Research, which is gratefully acknowledged.Peer reviewe