Cai L.-L.,CAS Nanjing Institute of Geography and Limnology |
Cai L.-L.,Wuxi Taihu Lake Management Company Ltd |
Zhu G.-W.,CAS Nanjing Institute of Geography and Limnology |
Zhu M.-Y.,CAS Nanjing Institute of Geography and Limnology |
And 2 more authors.
Water Science and Engineering | Year: 2012
Long-term variations of phytoplankton chlorophyll-a (Chl-a), nutrients, and suspended solids (SS) in Taihu Lake, a large shallow freshwater lake in China, during algal bloom seasons from May to August were analyzed using the monthly investigated data from 1999 to 2007. The effective accumulated water temperature (EAWT) in months from March to June was calculated with daily monitoring data from the Taihu Laboratory for Lake Ecosystem Research (TLLER). The concentrations of Chl-a and nutrients significantly decreased from Meiliang Bay to Central Lake. Annual averages of the total nitrogen (TN), total phosphorus (TP), and Chl-a concentrations, and EAWT generally increased in the nine years. In Meiliang Bay, the concentration of Chl-a was significantly correlated with EAWT, ammonia nitrogen (NH4 +-N), TN, the soluble reactive phosphorus (SRP), TP, and SS. In Central Lake, however, the concentration of Chl-a was only correlated with EAWT, TP, and SS. Multiple stepwise linear regression revealed that EAWT, dissolved total phosphorus (DTP), and TP explained 99.2% of the variation of Chl-a in Meiliang Bay, and that EAWT, NH4 +-N, and TP explained 98.7% of the variation of Chl-a in Central Lake. Thus EAWT is an important factor influencing the annual change of phytoplankton biomass. Extreme climate change, such as extremely hot springs or cold springs, could cause very different bloom intensities in different years. It is also suggested that both nutrients and EAWT played important roles in the growth of phytoplankton in Taihu Lake. The climate factors and nutrients dually controlled the risk of harmful algal blooms in Taihu Lake. Cutting down phosphorus and nitrogen loadings from catchments should be a fundamental strategy to reduce the risk of blooms in Taihu Lake. © 2012 Editorial Office of Water Science and Engineering.
Guijun Y.,CAS Nanjing Institute of Geography and Limnology |
Guijun Y.,Jiangnan University |
Boqiang Q.,CAS Nanjing Institute of Geography and Limnology |
Xiangming T.,CAS Nanjing Institute of Geography and Limnology |
And 4 more authors.
Journal of Great Lakes Research | Year: 2012
Zooplankton are an important link in aquatic food webs of lakes serving as consumers of algae, bacteria, and other microorganisms and as prey for fish and invertebrates. Despite their importance, little is known about the structure of the zooplankton communities of subtropic, large, shallow, eutrophic freshwater lakes. Our investigation of zooplankton communities in Lake Taihu, a subtropic, shallow, eutrophic lake and the third largest lake in China provides new information on this subject. Zooplankton, phytoplankton, and water chemistry samples were collected monthly from July 2006 to June 2007 in Meiliang and Gonghu Bays of Lake Taihu. Thirty zooplankton species were identified in Meiliang Bay with small-bodied cladocerans . Bosmina coregoni and . Ceriodaphnia cornuta contributing 21% and 11%, respectively to total zooplankton abundance which averaged 459. ind/L. Thirty-five species were identified in Gonghu Bay with the rotifers . Polyarthra trigla and . Brachionus calyciflorus the dominant species, contributing 21% and 11% respectively to total zooplankton abundance which averaged 467. ind/L. Predation by lake anchovy (. Coilia ectenes taihuensis) and ice fish (. Neosalanx tangkahkeii taihuensis) likely accounted for the dominance of both bays by small-bodied species. Community structure and community patterns were correlated with differences in . Microcystis blooms and organic matter levels (chemical oxygen demand) in the two bays. Based on canonical correspondence analyses dissolved total nitrogen, orthophosphate, . Cyclotella and . Pinnularia also contributed to variability in zooplankton community composition. © 2012.
Yang G.,Jiangnan University |
Yang G.,CAS Nanjing Institute of Geography and Limnology |
Qin B.,CAS Nanjing Institute of Geography and Limnology |
Tang X.,CAS Nanjing Institute of Geography and Limnology |
And 3 more authors.
Fresenius Environmental Bulletin | Year: 2012
A study on the zooplankton community was conducted in three areas of Lake Taihu: River Mouth, Meiliang Bay and Lake Center, from July 2006 to June 2007. Thirty-eight zooplankton species were identified in River Mouth, 29 in Meiliang Bay, 26 in Lake Center. The annual average density of zooplankton was 728 ind. I -1 in River Mouth, 459 ind. I -1 in Meiliang Bay, 355 ind. I -1 in Lake Center. The dominant species were Ceriodaphnia cornuta, Bosmina longirostris and Polyarthra trigla in River Mouth, Meiliang Bay and Lake Center, respectively. Our results suggested that the dominance of smaller crustaceans and rotifers in these lake areas may have different explanations. In River Mouth, high concentration of NH 4-N, COD Mn and high density of Chlorophyta may explain why rotifer was the dominant group. In Meiliang Bay, Microcystis blooms were likely to be the major factors why smaller crustaceans were dominant. And in Gonghu Bay, high suspended solids would be main cause of rotifer predominance. © by PSP.
Cai L.,Wuxi Taihu Lake Management Company Ltd |
Zhu G.,CAS Nanjing Institute of Geography and Limnology |
Li X.,Wuxi Taihu Lake Management Company Ltd
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013
In the lakes lacking higher aquatic plants, phytoplankton is the most important primary producer, and the basis of material circulation and energy flow in the aquatic ecosystems. Knowledge of phytoplankton primary productivity and its influencing factors is fundamental to the understanding of lake ecosystem dynamics and the assessment of lake ecosystem service functions. Although phytoplankton primary productivity in lakes had frequently been monitored and estimated using the black-and-white bottles, carbon isotope, remote sensing and optical data, there has a limited knowledge for phytoplankton primary productivity high-frequency variation and influencing factors. In our study, we analyzed phytoplankton primary productivity characteristics and influencing factors, using the high frequency monitoring data and synchronous anniversary in situ observation data in littoral zone of Meiliang Bay, Lake Taihu in 2010. Because the high frequency automatic monitoring data was missing from May to July, we used screening high frequency monitoring dissolved oxygen data to estimated phytoplankton daily primary productivity. Weekly results showed that the lowest phytoplankton primary productivity was recorded during the period from February to April with the mean daily gross primary productivity (GPP) less than 0.20 mgO2•L-1•h-1. During the period from August to October, phytoplankton primary productivity raised, and it reached the highest throughout the year in the second week of September with the maximal mean daily GPP of 1.34 mgO2•L-1•h-1, net ecosystem productivity (NEP) of 0.44 mgO2•L-1•h-1. During the period from November to December, phytoplankton primary productivity reduced with decreasing water temperature. Correlation analysis showed that the significant relationships were found between main components of phytoplankton (Cyanophyta, Chlorophyta, and Bacillariophyta) and GPP, NEP, and the trend of phytoplankton primary productivity was similar with the change of phytoplankton biomass. Thus the diurnal and seasonal variations of phytoplankton primary productivity can be reflected by the high frequency monitoring dissolved oxygen, making it is feasible to calculate phytoplankton primary productivity using high frequency algal bloom data. Statistical analysis also showed that water temperature is an important factor influencing the change of phytoplankton primary productivity in Lake Taihu. The supply of nitrogen and the selectivity prey of zooplankton were also important for the variations of phytoplankton primary productivity. The special topographic of lakeshore played an essential role in progress of algal piled, then impacted primary productivity; and this change was exacerbated by meteorological and hydrological processes, which reflected spatial and temporal heterogeneity of phytoplankton primary productivity of eutrophic lake. Based on the meteorological factors data during two algae accumulating periods in August and December, primary productivity changes are significantly influenced by meteorological factors. If there were large amounts of algae with Cyanobacteria as the dominant species, adequate sunlight to promote phytoplankton proliferating quickly, and steady wind to drive algae accumulating, phytoplankton primary productivity significantly increased in the lakeshore region. The high frequency dissolved oxygen monitoring can capture those algae accumulating processes. Thus the high frequency dissolved oxygen monitoring can be used in the monitoring of phytoplankton primary productivity and the warning of algal bloom disaster.
Guan Y.,Nanjing University of Information Science and Technology |
Zhang Y.,Suzhou University of Science and Technology |
Zhao D.,Auburn University |
Huang X.,Wuxi Taihu Lake Management Company Ltd |
Li H.,Wuxi Taihu Lake Management Company Ltd
Journal of the Air and Waste Management Association | Year: 2015
Lack of access to adequate sanitation facilities has serious health implications for rural dwellers and can degrade the ecosystems. This study offers a systemantic and quantitative overview of historical data on rural domestic waste (RDW) production and past and current management practices in a prototype region in China, where rural areas are undergoing rapid urbanization and are confronted with great environmental challenges associated with poor RDW management practices. The results indicate that RDW is characterized with a large fraction of kitchen waste (42.9%) and high water content (53.4%). The RDW generation (RDWG) per capita between 2012 and 2020 is estimated to increase from 0.68 to 1.01 kg/d-cap. The Hill 1 model is able to adequately simulate/project the population growth in a rural area from 1993 to 2020. The annual RDWG in the region is estimated to double from 6,033,000 tons/year in 2008 to 12,030,000 tons/year by 2020. By comparing three RDW management scenarios based on the life-cycle inventory approach and cost–benefit analysis, it is strongly recommended that the present Scenario 2 (sanitary landfill treatment) be upgraded to Scenario 3 (source separation followed by composting and landfill of RDW) to significantly reduce the ecological footprint and to improve the cost-effectiveness and long-term sustainability. Implications: Rural domestic waste (RDW) is affecting 720 million people in China and more than 3221 million people worldwide. Consequently, handling and disposal of RDW have serious health implications to rural dwellers and the ecosystems. This study offers a systemantic and quantitative overview and analysis of historical data on RDW production and management practices in a prototype region in China, which is confronted with great environmental challenges associated with RDW. Then we predict future production of RDW and propose a sustainable RDW management strategy, which holds the promise of greatly mitigating the mounting environmental pressure associated with RDW and provides science-based guidance for decision makers and practitioners for assuring rapid yet “green” economic development. © 2015 A&WMA.