Abstract: Typical sediments from Taihu Lake, a meso-to-hypereutrophic lake,
were collected and examined on the basis of P-fractionation by sequential
extraction scheme. Sedimentary inorganic phosphorus were fractioned into four
forms and the rank order according to the mean concentration of P-fractions in
Taihu Lake was NaOH-P > BD-P > HCI-P > NH_4Cl-P.
The concentrations of BD-P were linearly correlated with the content of active
Fe (R^2 = 0.96). Also, the linear relationship between the
sum of BD-P and NaOH-P and the sum of active Fe and active Al content was
observed within the six sediments investigated (R^2 = 0.96).
Moreover, the bio-available phosphorus (BAP) content was estimated by the sum
of NH_4CI-P, BD-P, and NaOH-P, viz. BAP =
NH_4CI-P + NaOH-P + BD-P. In Taihu Lake, the
BAPcontents are ranging from 0.10 mg/g dw to 1.25 mg/g dw, and average 0.40
mg/g dw for all sediment samples. The relative contributions of BAP to total
sedimentary phosphorus (TP) and inorganic sedimentary phosphorus (IP) range
from 18.67% to 50.79% (33.61% on average) and from 52.82% to 82.09% (67.81% on
average), respectively.
Keywords: phosphorus fractionation, bio-availability, sediment, Taihu Lake
