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Iron redox effects on photosensitive phosphorus release from dissolved humic materials
Author(s) -
Cotner James B.,
Heath Robert T.
Publication year - 1990
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.1990.35.5.1175
Subject(s) - environmental chemistry , chemistry , humic acid , redox , phosphorus , dissolved organic carbon , gel permeation chromatography , inorganic chemistry , organic chemistry , fertilizer , polymer
Factors controlling the release of P from dissolved humic material (DHM)‐iron complexes were studied in an acid bog lake. Gel‐permeation chromatography of lake water labeled with 32 PO 4 3− was used to separate high‐ and low‐molecular‐weight fractions of P compounds. Fe 3+ additions and irradiation with ultraviolet (UV) light increased the release of a labeled compound coeluting with orthophosphate from void volume fractions. Oxidation rates of Fe 2+ in whole‐lake water were much slower than photoreduction rates, which suggests that, in UV light, Fe accumulated as Fe 2+ . Fe 2+ concentrations decreased concomitant with a June increase in Chl a in the lake water. Biotic uptake of Fe 2+ may deplete the ambient pool of both Fe 2+ and Fe 3+ in summer and make photosensitive processes less important at this time.