Spatial and Temporal Distribution of Particulate Phosphorus and Their Correlation with Environmental Factors in a Shallow Eutrophic Chinese Lake (Lake Taihu)

Abstract

Spatial and seasonal variations of particulate phosphorus (PP) in a large shallow, eutrophic Lake Taihu with different ecotypes (including a phytoplankton-dominated zone, lake center zone, estuary zone and macrophyte-dominated zone) were investigated. The results showed that particulate organic phosphorus (POP) was the dominant form of PP (>88.0%). The concentration of POP showed higher levels in the bloom-sensitive northwestern zone (phytoplankton-dominated zone and estuary zone) during warm seasons, phytoplankton blooms and input of exogenous particulate matter were the main sources of POP in the lake water. Based on 31P nuclear magnetic resonance (31P NMR) analysis, orthophosphate (Ortho-P) was the dominant molecular species of PP and positively correlated with soluble reactive phosphorus (SRP) (p < 0.01). This suggested that the release of Ortho-P from suspended particulate matter (SPM) was the main source of SRP in the lake water. Pyrophosphate (Pyro-P), which is regarded as a highly labile species of P compounds, represented a large fraction of PP, and its significant positive correlations with chlorophyll a (Chl a), indicated that the concentration of Pyro-P could be used as an important indicator for the degree of eutrophication of Lake Taihu. These results proved that PP in lake water was a significant factor supporting lake eutrophication and must be controlled.

Seasonal Release Potential of Sediments in Reservoirs and its Impact on Water Quality Assessment

“…The adsorption and release characteristics of sediments change with the contents of the overlying water, physicochemical properties of sediments [17,18], water temperature (T W ) [19], dissolved oxygen (DO) [20], pondus hydrogenii (pH) conditions [21], and other environmental factors [22,23]. For reservoirs in the monsoon climate zone, environmental and water quality indicators vary with seasonal changes, which cause the adsorption and release characteristics of the sediments to change seasonally.…”

Spatial heterogeneity of food web structure in a large shallow eutrophic lake (Lake Taihu, China): implications for eutrophication process and management

“…For instance, enclosure culture in East Taihu Bay (the region Site 5 located) reached its peak from 1998 to 2008 (Wang et al 2019). Although suffered a mass of anthropogenic organic matter inputs, the water quality of East Taihu Bay was better than that of algae-dominated zone (Kong et al 2018). It seems that the large area of submerged macrophytes and floating-leaf macrophytes play important role in maintain water quality and favorable food web structure.…”

Degradation Characteristics of Phosphorus in Phytoplankton-Derived Particulate Organic Matter and Its Effects on the Growth of Phosphorus-Deficient Microcystis aeruginosa in Lake Taihu

“…Some studies indicated that Pyro-P was a degradation product of Poly-P under the action of microbial metabolism; Poly-P and Pyro-P are both potential bioavailable phosphorus, which are actively involved in the P circulation in water and are closely related to the nutrient level of lakes. [18,45].…”

“…A large number of microorganisms can be attracted or reproduced on the surface of PPOM to carry out strong bio-metabolic activities [16,17]. The more easily decomposed PPOM can rapidly degrade through a series of redox and phosphatase hydrolysis processes, releasing various species of P to the surrounding water body [18]. Part of P entering the water body is dissolved in water and can be directly absorbed and utilized by algae and other organisms [19]; part of P enters the sediment with the deposition of particulate matter and then suspends under the disturbance of wind, waves, and organisms, re-entering the overlying water body and participating in the P cycle [20].…”