title: Manipulating nutrient limitation using modified local soils: A case study at Lake Taihu (China).
abstract: The effect of geo-engineering materials of chitosan modified local soil (MLS) on nutrient limitation was studied in comparable whole ponds in Lake Taihu in October 2013. After 20 kg MLS were sprayed in the whole water pond (400 m(2)), the chlorophyll-a (Chl-a) concentration was decreased from 42 to 18 μg L(-1) within 2 h and remained below 20 μg L(-1) in the following 15 months, while the average Chl-a was 36 μg L(-1) in the control pond throughout the experiment. In situ nutrient addition bioassay experiments indicated that the nutrient limitation was shifted from nitrogen (N) and phosphorus (P) co-limitation to P limitation after MLS treatment from October 2013 to March 2014 compared to the control pond. In the cyanobacterial bloom season of June 2014, N and P co-limitation remained and N was the primary limiting nutrient and P was a secondary one in the control pond where phytoplankton biomass showed significant increase by N addition and further increase by N + P additions, while both N and P became the limiting nutrient for phytoplankton growth where only combined N and P additions showed significant Chl-a stimulation in the treatment pond. In the next summer (June 2014), a cyanobacteria-dominated state still remained in the control pond but chlorophytes, bacillariophytes and cyanophytes distributed equally and submerged vegetation was largely restored in the treatment pond. Meanwhile, the upper limiting concentration of DIN was enhanced from 0.8 to 1.5 mg L(-1) and SRP from 0.1 to 0.3 mg L(-1) compared to the control pond. This study indicates that nutrient limitation can be manipulated by using MLS technology.
authors.affiliation: Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Lijing
authors.initials: L
authors.lastname: Wang
authors.affiliation: Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Animal, Rural, and Environmental Sciences, Nottingham Trent University, NG25 0QF, UK. Electronic address: gpan@rcees.ac.cn.
authors.forename: Gang
authors.initials: G
authors.lastname: Pan
authors.affiliation: Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Shi
authors.affiliation: Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Honggang
authors.initials: H
authors.lastname: Zhang
mesh_terms: D002681:China; D060106:Lakes; D009584:Nitrogen; D010758:Phosphorus; D010839:Phytoplankton; D012987:Soil
chemical_list: D012987:Soil; D010758:Phosphorus; D009584:Nitrogen
keywords: Modified local soil; Nutrient limitation; Phytoplankton biomass and composition; Submerged vegetation restoration; Whole lake experiment