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Distribution and Biological Availability of Reactive High Molecular Weight Phosphorus in Natural Waters in New Zealand

1980; Canadian Science Publishing; Volume: 37; Issue: 4 Linguagem: Inglês

10.1139/f80-083

1205-7533

Edward M. White, G. Payne,

Water Quality and Pollution Assessment

Eutrophic lakes and many streams on the central volcanic plateau of the North Island, New Zealand, contain dissolved chemically reactive phosphorus which is not orthophosphate. Sephadex gel (G25-150) chromatograms reveal that one reactive component is of high molecular weight (MW > 5000) while a second component elutes in the same way as phosphate-phosphorus (PO 4 -P). The reactive high molecular weight phosphorus (RHMW-P) in streams generally forms only a small proportion of the dissolved reactive phosphorus (DRP). In some eutrophic lakes the proportion of RHMW-P in the DRP is high (70–80%). Each lake may have a characteristic distribution of the two forms of reactive phosphorus. In summer where DRP concentrations are low (<2 mg∙m −3 ) in lake surface waters, PO 4 -P seems to dominate over RHMW-P which is consistent with long 32 PO 4 turnover times which are found in many of the central volcanic plateau lakes. Algal growth responses to phosphorus uptake were similar for PO 4 -P and RHMW-P, but not all of the RHMW-P was taken up by Chlorella in bioassays. The proportion of the RHMW-P taken up by Chlorella was different for each lake examined, posing problems in relating DRP concentrations to algal growth responses in lakes.Key words: reactive phosphorus, phosphate-phosphorus, algae, Chlorella, growth, bioassay, freshwater analysis, molybdenum blue method, Sephadex gel chromatography