Remote sensing provides fundamental spatial-temporal information on lake dynamics and related drivers, climate and land use. Satellite data continuity over the last decades enhances our capabilities for assessing long term ecosystem responses to regional and local environmental change. Lake Taihu, water source for some million people, is the third largest freshwater lake in China, and one of the most severely polluted. In this study, we show a decadal assessment of water quality stressors in Lake Taihu watershed, integrating monthly time series of MODIS derived estimates of catchment land use (agricultural activity) and algal blooms, together with climate data and nutrient concentrations. We carried out a comparative analysis of algal blooming events and potential stressors. According to our results, prior to 2006, bloom extension and starting date were strongly controlled by nutrient availability. After the exceptional blooms of 2006-07, a shift to other catchment scale stressors was observed, including climate. This suggested the lake had moved towards a condition of nutrient saturation. More recent data indicate that algal bloom control factors may be returning to pre-2006 conditions
A decadal assessment of water quality stressors over Lake Taihu area using in situ and MODIS satellite data
Paolo Villa;
2015
Abstract
Remote sensing provides fundamental spatial-temporal information on lake dynamics and related drivers, climate and land use. Satellite data continuity over the last decades enhances our capabilities for assessing long term ecosystem responses to regional and local environmental change. Lake Taihu, water source for some million people, is the third largest freshwater lake in China, and one of the most severely polluted. In this study, we show a decadal assessment of water quality stressors in Lake Taihu watershed, integrating monthly time series of MODIS derived estimates of catchment land use (agricultural activity) and algal blooms, together with climate data and nutrient concentrations. We carried out a comparative analysis of algal blooming events and potential stressors. According to our results, prior to 2006, bloom extension and starting date were strongly controlled by nutrient availability. After the exceptional blooms of 2006-07, a shift to other catchment scale stressors was observed, including climate. This suggested the lake had moved towards a condition of nutrient saturation. More recent data indicate that algal bloom control factors may be returning to pre-2006 conditionsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
