抄録
The iron concentration and its size fraction were investigated in 15 reservoirs which trophic levels varied from oligotrophic types to eutrophic ones. The T-Fe concentration ranged from 0.021 to 2.349 mg· 1-1, and the average value of the concentration from the all samples (n=123) was 0. 200 mg· l-1, The D-Fe (<0.45μm size) concentration was about 20% of T-Fe, but someti-mes appeared to be above 50% when the T-Fe concentration was relatively low. The relationship between T-Fe and Chlorophyll-a was not clear enough to obtain a specific correlation as compared with that of T-P or T-N and Chlorophyll-a. One significant factor of this scatter was the difer-ence of the iron contents between algal cell particle (0.24%) and non-algal cell particle (3. 9%).
The D-Fe (<0.45μm size) concentration showed poor relationship with DOC which was quantitative index of desolved organic matters. On the other hand, better relationship was showed with E260 or DOC/E260 value which were qualitative index of desolved organic matters.
The examination of the three fraction of iron under the size of 1.0 /μm size showed that about 20% of the iron was the size of both 1. 0-0. 45μm and 0. 45-0. 10μm, and also 60% was size of less than 0.10μm. It suggested the concentration of D-Fe must be carefully defined by the physical sieving size for the consideration of algal availability of iron.
