Spatial identification of critical nutrient loads of large shallow lakes: Implications for Lake Taihu (China)

WATER RESEARCH

卷:119

Article

Janssen, Annette B. G.^1,2  de Jager, Victor C. L.¹  Janse, Jan H.^1,3  Kong, Xiangzhen^1,4  Liu, Sien^5,6  Ye, Qinghua^5,6  Mooij, Wolf M.^1,2 

[1] Netherlands Inst Ecol, NIOO KNAW, Dept Aquat Ecol, POB 50, NL-6700 AB Wageningen, Netherlands

[2] Wageningen Univ & Res, Dept Aquat Ecol & Water Qual Management, POB 47, NL-6700 AA Wageningen, Netherlands

[3] Netherlands Environm Assessment Agcy, PBL, POB 30314, NL-2500 GH Den Burg, Netherlands

[4] Peking Univ, Coll Urban & Environm Sci, MOE Lab Earth Surface Proc, Beijing 100871, Peoples R China

[5] Deltares, POB 177, NL-2600 MH Delft, Netherlands

[6] Delft Univ Technol, Sect Hydraul Engn, Fac Civil Engn & Geosci, POB 5048, NL-2600 GA Delft, Netherlands

关键词: Eutrophication;    Spatial heterogeneity;    Bifurcation analysis;    PCLake;    Load-response curve;    Algal blooms;   

DOI  :  10.1016/j.watres.2017.04.045

来源: Elsevier

【 摘 要 】

Ongoing eutrophication frequently causes toxic phytoplankton blooms. This induces huge worldwide challenges for drinking water quality, food security and public health. Of crucial importance in avoiding and reducing blooms is to determine the maximum nutrient load ecosystems can absorb, while remaining in a good ecological state. These so called critical nutrient loads for lakes depend on the shape of the load-response curve. Due to spatial variation within lakes, load-response curves and therefore critical nutrient loads could vary throughout the lake. In this study we determine spatial patterns in critical nutrient loads for Lake Taihu (China) with a novel modelling approach called Spatial Ecosystem Bifurcation Analysis (SEBA). SEBA evaluates the impact of the lake's total external nutrient load on the local lake dynamics, resulting in a map of critical nutrient loads for different locations throughout the lake. Our analysis shows that the largest part of Lake Taihu follows a nonlinear load-response curve without hysteresis. The corresponding critical nutrient loads vary within the lake and depend on management goals, i.e. the maximum allowable chlorophyll concentration. According to our model, total nutrient loads need to be more than halved to reach chlorophyll-a concentrations of 30-40 mu g L-1 in most sections of the lake. To prevent phytoplankton blooms with 20 mu g L-1 chlorophyll-a throughout Lake Taihu, both phosphorus and nitrogen loads need a nearly 90% reduction. We conclude that our approach is of great value to determine critical nutrient loads of lake ecosystems such as Taihu and likely of spatially heterogeneous ecosystems in general. (C) 2017 The Authors. Published by Elsevier Ltd.

【 授权许可】

Free