Two-Decade Reconstruction of Algal Blooms in China’s Lake Taihu

Abstract

The algal blooming in the inland lakes has become a critically important issue for its impacts not only on local natural and social environments, but also on global human community. However, the occurrences of blooming on larger spatial scale and longer time scale have rarely been studied. As the third largest freshwater lake in China, Lake Taihu has drawn increasing attention from both public and scientific communities concerning its degradation. Using available satellite images, we reconstructed the spatial and temporal patterns of algal blooms in Lake Taihu through the pasttwo decades. The blooming characteristics over the past two decades were examined with the dynamic of initial blooming date being highlighted. The initial blooming dates were gradually becoming later and later from 1987 to 1997. Since 1998, however, the initial blooming date came earlier and earlier year by year, with approximately 11.42 days advancement per year. From 1987 to 2007, the annual duration of algal blooms lengthened year by year, in line with the substantial increases in the occurrences of algal blooms in spring and summer months. The algal blooms usually occur in northern bays and spread to center and south parts of Lake Taihu. The increases in previous winter's mean daily minimum temperature partially contributed to the earlier blooming onset. However, human activities, expressed as total gross domestic product (GDP) and population, outweighed the climatic contribution on the initial blooming date and blooming duration. This study may provide insights for the policy makers who try to curb the algal blooming and improve the water quality of inland freshwater lakes.

Phylogenetic beta diversity in bacterial assemblages across ecosystems: deterministic versus stochastic processes

“…Two groups from Taihu Lake (ThS and ThW) had mean ses.betaMNTD values that were less than zero (Supplementary Figure S3), suggesting that for both groups there was relative consistency in the environmental conditions that deterministically governed community composition. Although many features of the observed abiotic environment in Taihu Lake varied across sampled communities, a high level of eutrophication was maintained across communities (Duan et al, 2009). It may therefore be that high eutrophication imposed strong environmental filtering on microbial communities in Taihu Lake.…”

Heavy metal migration and risk transference associated with cyanobacterial blooms in eutrophic freshwater

“…West (n = 16) South (n = 24) (Song et al, 2007;Duan et al, 2009;Ye et al, 2009). It is assumed that water from Lake Taihu might present a risk of heavy metal transfer from the lake into crops grown using the water from the lake for irrigation.…”

“…A large number of studies have indicated that Lake Taihu is profoundly affected by cyanobacterial blooms, and control strategies such as reducing nutrient by sediment dredging and chemical methods, and phytoremedation have been implemented in the last few years (Duan et al, 2009;Paerl et al, 2011;Zhang et al, 2016;Tang et al, 2016;Xu et al, 2017). In our previous study, we focused on the investigation how mechanical collection of cyanobacterial biomass was degraded in the artificial ponds and the risk associated with this process (Chen et al, 2012).…”

Eutrophication in a Chinese Context: Understanding Various Physical and Socio-Economic Aspects

“…5). There are considerable evidences (surface water chemistry, sediment cores, and satellite imagery) indicating that these three lakes are experiencing significant increases in algal productivity both over time and space (Duan et al 2009;Shang and Shang 2007;Zhu 2008). From 1987 to 2007, algal blooms in Taihu Lake occurred at increasing frequency and on lengthened duration while the distribution area became larger and larger year by year (Duan et al 2009).…”

“…There are considerable evidences (surface water chemistry, sediment cores, and satellite imagery) indicating that these three lakes are experiencing significant increases in algal productivity both over time and space (Duan et al 2009;Shang and Shang 2007;Zhu 2008). From 1987 to 2007, algal blooms in Taihu Lake occurred at increasing frequency and on lengthened duration while the distribution area became larger and larger year by year (Duan et al 2009). The average TSI (Trophic State Index) of western Chaohu Lake increased slightly from 72.6 between 1984 and 1991 to 75.4 between 1998 and 2004 in spite of the fact that during last two decades a series of measures have been taken by national and local government to restrain the eutrophication process in the lake (Shang and Shang 2007).…”