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The effect of pH, dissolved humic substances, and ionic composition on the transfer of iron and phosphate to particulate size fractions in epilimnetic lake water
Author(s) -
Shaw Peter J.
Publication year - 1994
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1994.39.7.1734
Subject(s) - ionic strength , particulates , chemistry , phosphate , precipitation , composition (language) , environmental chemistry , phosphorus , aqueous solution , linguistics , physics , philosophy , organic chemistry , meteorology
Transformations of dissolved iron and phosphate to particulate material (>0.2 µ m) were investigated by adding 55 FeCl 3 and 32 PO 4 3 to pH adjusted epilimnetic lake water samples of contrasting ionic strengths and dissolved humic substances (DHS) concentrations. The distributions of these tracers between particulate size fractions in samples without appreciable DHS after 24 h of dark incubation varied markedly over the pH range 4–8. The effect of pH on the movement of 55 Fe and 32 P to particulate size fractions in clear‐water samples depended on the ionic strength. Over the same pH range, the presence of DHS suppressed the movement of 55 Fe and 32 P to particulate size fractions. There was little difference between low and high ionic strength DHS‐rich samples. The capability of DHS to maintain added 55 Fe and 32 P in solution (<0.2 µ m) was confirmed by simultaneous measurements of precipitation losses.