Rezumat articol ediţie STUDIA UNIVERSITATIS BABEŞ-BOLYAI

În partea de jos este prezentat rezumatul articolului selectat. Pentru revenire la cuprinsul ediţiei din care face parte acest articol, se accesează linkul din titlu. Pentru vizualizarea tuturor articolelor din arhivă la care este autor/coautor unul din autorii de mai jos, se accesează linkul din numele autorului.

 
       
         
    STUDIA GEOLOGIA - Ediţia nr.1 din 2007  
         
  Articol:   OXYGEN ISOTOPE EVIDENCE FOR UNUSUALLY HIGH EVAPORATION RATES FROM BUDZISłAWSKIE LAKE (CENTRAL POLAND).

Autori:  D. LEWICKA-SZCZEBAK, A. TROJANOWSKA.
 
       
         
  Rezumat:  Here we present the results of oxygen isotopic analyses carried out on water samples from Budzisławskie Lake (Central Poland). The lake has neither tributaries nor outflows, being supplied most probably only by precipitation waters (no evidence for groundwater supply). For several years a serious decrease in water level has been observed in this lake (e.g., in the hydrological year 2003/2004 the water table has lowered with about 0.3 m). The total annual rainfall of the year 2003 was as low as 344 mm, and in the year 2004 it raised to 440 mm – this area shows a significant water deficit (average annual precipitation in Poland is about 550 mm). Our study was aimed at determining the possible reasons for the observed water loss. The oxygen isotopic analyses of the water have been done in order to estimate the rate of evaporation from the lake’s surface and its direct catchment. The water samples of Budzisławskie Lake have been collected on 3rd October 2005 from 3 sampling points and from 3 different depths at each sampling point (9 samples analyzed). The δ18O values vary between -2.36‰ and -1.78‰ (an extremely high value compared to typical δ18O values for lake waters in Poland, averaging -9‰, or to precipitation waters averaging -10.1‰). Such a large enrichment in heavy oxygen isotopes in the Budzisławskie Lake is, in our opinion, due to intensive evaporation. Using the Rayleigh distillation model we calculated that 56% of the water supplied by precipitation evaporated from the lake and from its direct catchment. We assumed that water from precipitations (falling directly into the lake and coming through its direct catchment) is the only water supply for the lake and that there is no outflow (e.g., to groundwater). Consequently, it can be calculated that the evaporation was responsible for an up to 6 m decrease of the water level of Budzisławskie Lake.  
         
     
         
         
      Revenire la pagina precedentă