es305297y_si_001.pdf (1.3 MB)
Phosphite in Sedimentary Interstitial Water of Lake Taihu, a Large Eutrophic Shallow Lake in China
journal contribution
posted on 2016-02-19, 07:25 authored by Chao Han, Jinju Geng, Hongqiang Ren, Shixiang Gao, Xianchuan Xie, Xiaorong WangThe
seasonal occurrence and distribution of phosphite (HPO32‑, P) in sedimentary interstitial water
from Lake Taihu was monitored from 2011 to 2012 to better understand
its possible link to P cycle in the eutrophic shallow lake. Phosphite
concentrations ranged from < MDL to 14.32 ± 0.19 μg
P/kg with a mean concentration of 1.58 ± 0.33 μg P/kg,
which accounts for 5.51% total soluble P (TSPs) in surficial
sediments (0–20 cm). Spatially, the concentrations of sedimentary
phosphite in the lake’s northern areas were relatively higher
than those in the southern areas. Higher phosphite concentrations
were always observed in seriously polluted sites. Generally, phosphite
in the deeper layers (20–40 cm and 40–60 cm) showed
minor fluctuations compared to that in the surficial sediments, which
may be associated with the frequent exchange at the sediment–water
interface. Phosphite concentrations in surficial or core sediments
decreased as spring > autumn > summer > winter. Higher phosphite
levels
occurred in the areas with lower redox (Eh), higher P contents, and
particularly when metal bonded with P to form Al–Ps and Ca–Ps. Phosphite may be an important media
in the P biogeochemical cycle in Lake Taihu and contribute to its
internal P transportation.