Results of Monitoring at Olkiluoto in 2006 - Environment (pdf) - Posiva

29of both PO 4 -P and Mn in stand throughfall is normally higher than that in bulk deposition.However, the other elements are not normally measured in bulk deposition in studieson ecosystem functioning, and therefore it is difficult to find comparable resultsfrom the literature. An increase in Fe, Mn and Si is understandable because these elementsare associated with mineral dust (e.g. from forest roads), but Al would also havebeen expected to increase correspondingly. The deposition of PO 4 -P, Al, Fe, Mn, Cu,Zn and Si in bulk deposition and stand throughfall was relatively similar in 2006 to thelevels in 2004 and 2005.Forest Intensive Monitoring Plot: FIPSoil SolutionThe results of the soil solution monitoring in 2004-2006 were originally reported byJohn Derome (Finnish Forest Research Institute) in a memo and are summarized below.The result tables can be found in Appendix F.The plate lysimeters at a depth of 5 cm functioned well on FIP4 during the monitoringperiod, the samples having been obtained on almost all sampling occasions (at ca. fourweek intervals). Despite the relatively dry summer in 2005, and especially in 2006, thesuction-cup lysimeters also provided samples on seven sampling occasions (ca. fourweek intervals) from 24.5.2005 to 7.11.2005 and on five occasions from 23.5. to2.11.2006. In July 2006, no samples were obtained because precipitation was only 1.6mm. The plate lysimeters installed at a depth of 5 cm on the spruce plot yielded samplesonly on two occasions in 2005 (5.8. and 6.9.), but on five occasions in 2006 (19.6.,14.8., 11.9., 10.10. and 2.11.).In FIP4 the amount of percolation water passing down to a depth of 5 cm during thesnow-free period (Fig. 20, Table F-1) was ca. 17% of the input to the forest floor (standthroughfall) in 2004, ca. 21% in 2005, and ca. 16% in 2006. There was considerablevariation between the sampling dates due primarily to the varying amounts of standthroughfall. The amounts were especially low after snowmelt in the latter half of Mayand the first half of June in 2004, and in July and August in 2006. Overall, the proportionof water passing down to a depth of 5 cm was relatively similar in all years, withslightly lower values in the dry parts of summer in 2004 and 2006.