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

Ming Kong,Wei Han,Jianying Chao,Chun Ye,Chun-Hua Li,Wei Tian

doi:10.3390/ijerph16122155

Abstract

To illustrate the contribution of phytoplankton-derived particulate organic matter (PPOM) to endogenous phosphorus (P) cycling and its effects on cyanobacteria blooms, PPOM characteristics, the degradation mechanism, and the growth of P-deficient Microcystis aeruginosa were studied in Lake Taihu. Results showed that PPOM is the most important P pool in the water column during cyanobacteria bloom, accounting for more than 80% of the total P (TP) in the water. During PPOM degradation, the particulate orthophosphate (Ortho-P) is the main species of P release from PPOM in the early degradation stage. The variations of polyphosphate (Poly-P) and phosphodiesters (Diester-P) contents were most significant, which were degraded completely within four days and eight days. Cell density and growth rate of M. aeruginosa using PPOM as P source were similar to those growing on Na2HPO4. The above results show that P in PPOM can be converted into available P by degradation, thus promoting the growth of M. aeruginosa. Therefore, the contribution of P release from PPOM degradation needs to be paid attention to in lake eutrophication control in the future.

Highlights

Lake eutrophication has become one of the major ecological and environmental problems worldwide and can lead to the frequent occurrence of cyanobacterial blooms [1,2]
The general characteristics of water and phytoplankton-derived particulate organic matter (PPOM) are shown in Table 1; the temperature of the culture system was kept consistent at about 30 ◦ C
At the end of the experiment, Dissolved oxygen (DO) returned to its starting value

Summary

Introduction

Lake eutrophication has become one of the major ecological and environmental problems worldwide and can lead to the frequent occurrence of cyanobacterial blooms [1,2]. Phosphorus (P) is an indispensable element for phytoplankton growth in freshwater systems and a determinant factor of eutrophication [3]. Once the inputs of exogenous P are effectively controlled, internal P recycling is the most important source of P for primary production and maintaining the trophic status and cyanobacterial blooms [4]. Particulate organic matter (POM) is an important component of aquatic ecosystem and a nutrient carrier [5]. POM degradation is accompanied by P cycling [6]. POM includes exogenous imported POM and endogenous POM.

Methods

Results

Discussion

Conclusion