CAS to Address Water Eutrophication

At a meeting on April 5, the CAS authorities gave the green light to a proposal to carry out studies on the development and control of eutrophication on the middle and lower reaches of the Yangtze River. The five-year project,to cost 20 million yuan (about USS 2.4 million), will involve scientists from various CAS institutes, including the Nanjing Institute of Geography & Limnology, Wuhan Institute of Hydrobiology, Research Center for Eco-Environmental Sciences, Wuhan Institute of Botany, Institute of Chemistry, Institute of Geodesy & Geophysics, and Institute of Microbiology.

Study on the Changes of Physiological Indexes of Water Spinach in Eutrophication Water

[Objective] Effect of hypoxic water culture on physiological characteristic of water spinach and its hypoxia tolerance were studied.[Method] Water spinach was planted in soil and eutrophication water by means of floating bed,respectively,and the change of physiological indexes including chlorophyll,proline（Pro）,malondialdehyde（MDA）,soluble sugar and soluble protein in water spinach leaves at mature stage was researched,while the hypoxia tolerance of water spinach and the effect of plant density on water spinach growth were discussed in our paper.[Result] In the hypoxic eutrophication water,the content of total chlorophyll,malondialdehyde,soluble sugar and soluble protein in water spinach leaves was lower than that of soil culture,with higher proline content,which showed that water spinach had better tolerance to hypoxic eutrophication water;the higher the plant density,the lower the chlorophyll content in water spinach leaves,and there was no significant effect of plant density on proline and malondialdehyde content,while soluble protein content was higher under high plant density.[Conclusion] The best plant density of water spinach was 66 plants per floating bed with the area of 2 m2,which could provide theoretical basis for the application of water spinach in floating bed.

Research Progress on Application of Ipomoea aquatica Floating Bed in Eutrophication Water

Research progresses on growth characteristics,application effect and optimization technology of I. aquatica floating bed were reviewed;its application problems in eutrophication water were discussed,and its application prospect was forecasted.

Ecological Monitoring Perspectives from Biotesting of Surface Waters： A Study of Pavlovsk Reservoir （Bashkortostan, Russia）

The cost of environmental analysis is becoming astronomically high at the global scale. One of the major trends in the respective research activities is the development of biotesting methods. Such methods, in addition to ecotoxicology, are highly demanded for environmental monitoring and ecological standardization. The development of biotesting in toxicology, however, is limited to the ＂battery of tests＂ paradigm, while environmental monitoring and ecological standardization are based on the ＂uniformity of measurements＂ paradigm. A ＂reference bioindicator＂ is proposed to harmonize these approaches. A reference bioindicator serves for comparison of data obtained by different bioindicators. This method was approved for the state environmental control. Application of reference bioindicators makes analytical procedure substantially cheaper. It requires, however, thorough calibration in relation to specific environmental factors （such as temperature, photoperiod etc.） as well as to specific active agents and their combinations. This problem can be solved with the start-up of calibrating analytical centers and long-term study of the effects of spatiotemporal environmental factors in specific areas and for specific reference objects. This paper demonstrates long-term study results for the surface waters of Pavlovsk reservoir （Bashkortostan, Russia）.

Prevention of Reservoir Water Bloom by Bio-manipulation

Siminghu Reservoir already transformed into ＂ the algae muddy＂ type,and had nonclassical bio-manipulation practice using Hypophthalmichthys molitix and Aristichthys nobilis to feed the plankton,control water bloom and transform the organic matters into fish product. Through the analysis of the limited data,we think that water bloom of Siminghu Reservoir can be prevented to some extent by breeding H. molitix and A. nobilis,and it can slow down eutrophication of reservoir but cannot control the eutrophication tendency. We must take a variety of comprehensive management measures to control eutrophication from the angle of basin control,and guarantee safety of drinking water resources.

A model for integrated spatial land use characteristics linking to surface nutrient concentration

Quantifying land use heterogeneity helps better understand how it influences biophysical systems.Land use area proportions have been used conventionally to predict water quality variables.Lacking an insight into the combined effect of various spatial characteristics could lead to the statistical bias and confused understanding in previous studies.In this study,using spatial techniques and mathematical models,a diagnostic model was developed and applied for quantifying and incorporating three spatial components,namely,slope,distance to sampling spots,and arrangement.The upper catchment of Miyun Reservoir was studied as the test area.Total nitrogen,total phosphorus,and chemical oxygen demand of water samples from field measurements were used to characterize the surface water quality in 52 sub-watersheds.Using parameter calibrations and determinations,combined spatial characteristics were explored and detected.Adjusted land use proportions were calculated by spatial weights of discriminating the relative contribution of each location to water quality and used to build the integrated models.Compared with traditional methods only using area proportions,our model increased the explanatory power of land use and quantified the effects of spatial information on water quality.This can guide the optimization of land use configuration to control water eutrophication.