Το νερό στη χημική εκπαίδευση: έννοιες, παρανοήσεις, δυσκολίες στην κατανόηση

Abstract

In the present study, wetlands of the areas of Acheloos river Delta, Strofilia, Vasiliki and Krioneri are studied from the ecological point of view and their flora and vegetation are correlated with the main abiotic factors of soil and water. For the survey of the flora and the vegetations units’ identification a sufficient number of samplings were made in representative sites of relevant vegetation units of the studied areas. In every sampling site, samples of soil and water - where it was possible - have been also taken, for laboratory processing. On-site measurements have been taken for following water parameters: pH, temperature, redox, alkalinity, CO2 and conductivity. Soil samples were analysed in the laboratory and the identified parameters were: soil particles size (%), soil moisture (%), pH and conductivity, CaCO3 (%,), organic matter (%), total N (mg/100gr, Kjehldahl method), P (mgr / kgr, Olsen method), K (meq/100gr, in ammonium acetate pH 7.0). Water samples were additionally analysed in the laboratory and following parameters were identified: Κ, Νa, Ca, Μg, Cl , ΗC031-, Ν031-,, Ν021-, ΝΗ41+ και S042-. From the parameters statistical analysis those statistically significant were obtained and then correlated with the determined vegetation units and subunits. From the floristic analysis, 405 taxa were identified from the four study areas and more specific, 234 from the Acheloos Delta, 240 from Strofilia, 115 from Vasiliki and 38 from Kryoneri. 176 taxa of them are new records, 4 are Greek endemics and 26 are under a protection status. The life-form spectrum shows that therophytes dominate, followed by hemicryptophytes, except of Kryoneri, where hemicryptophytes and geophytes predominate. The chorological spectrum shows that the Mediterranean chorological elements 192 dominate, followed by Cosmopolitan-Subcosmopolitan ones. From the vegetations analysis five (5) units and eleven (11) subunits were distinguished, as follows: Unit I: Vegetation Groups of shifting dunes ? Subunit Ia. Community with Cakile maritima ? Subunit Ib. Community with Elymus farctus ? Subunit Ic. Community with Ammophila arenaria Unit II: Vegetation Groups of fixed dunes ? Subunits IIa & I Ic. Communities with Juniperus phoenicea ? Subunit IIb. Communities of dune slucks with Bolboschoenus maritimus Unit III: Vegetation Groups of salt meadows and marshes (high salinity) ? Subunit IIIa. Communities with Salicornia and Arthrocnemum, Community with Ruppia maritima ? Subunit IIIb. Communities with Juncus maritimus - J. acutus, Community with Cotula coronopifolia, Community with Tamarix Unit IV: Vegetation Groups of wetlands of lower / moderate salinity Community with Scirpus lacustris - Juncus maritimus Unit V: Vegetation Groups of wetlands of low salinity ? Subunit Va. Community with Cladium mariscus ? Subunit Vb. Communities with Phragmites and Scirpus From the correlation between environmental factors and flora-vegetation we concluded followings: