Total inputs of phosphorus and nitrogen by wet deposition into Lake Taihu, China

Abstract

Lake Taihu suffers from eutrophication caused by riverine nutrient inputs and air deposition. To characterize wet deposition of phosphorus (P) and nitrogen (N) to the lake, precipitation collection and measurements of total phosphorus (TP) and total nitrogen (TN) and other components at five cities around Lake Taihu were made from July 2002 to June 2003. TP and TN concentrations and deposition rates exhibited strong spatial variation in the whole catchment. An inverse correlation between station-averaged TP and TN concentrations and precipitation amount was found. Maximal TP concentration in rainfall was found in Suzhou, and maximal TN in Wuxi. However, highest wet deposition rates of TP and TN were found in Suzhou, which suggests that atmospheric nutrients are mostly from the east and northwest area of Lake Taihu. Mean TP and TN deposition rates were 0.03 and 2.0 t km -2 year -1 respectively in Lake Taihu, which are greater than reported values in other areas by comparision. Total N and P contributed to the lake by wet deposition were 75 and 4720 t per year, respectively, which represent about 7.3% and 16.5% of total annual N and P inputs via inflow rivers. Wet deposition, especially N, could have significant effects on eutrophication in the lake, which shows that air deposition should be taken into account while reducing the external nutrients in the lake.

The influence of water quality and sediment geochemistry on the horizontal and vertical distribution of phosphorus and nitrogen in sediments of a large, shallow lake

“…However, the difference between water column and sediment TN:TP ratios in Lake Taihu is similar to that found in shallow eutrophic Lake Ellesmere (area = 182 km 2 ), New Zealand (Hamilton & Mitchell, 1997). Furthermore, a Lake Taihu nutrient budget for the hydrological year 2001-2002 (Xu & Qin, 2005), which was subsequently updated to include atmospheric wet deposition (Luo et al, 2007), suggests that around 60% of the nitrogen that enters the lake cannot be accounted for, presumably as a result of denitrification. The TC:TN ratios in the surficial sediments, based on the data collected in 2006, are similar to the Redfield ratio, suggesting that the vast majority of nitrogen in the sediments is associated with organic material.…”

Absorption and fluorescence characteristics of rainwater CDOM and contribution to Lake Taihu, China

“…The resulting increase in dry and wet deposition has important chemical and biological effects on aquatic ecosystems (Ballantyne et al, 2011). For instance, dust deposition is an important source of nitrogen and phosphorus in many alpine and eutrophic lakes (Ballantyne et al, 2011;Luo et al, 2007;Zhai et al, 2009), and can shift the N:P stoichiometry of the water; as a result, phytoplankton growth is promoted (Elser et al, 2009;Zhai et al, 2009).…”

Effects of water transfer on water quality and estimation of the pollutant fluxes from different sources into West Lake, Hangzhou City, China

“…in the atmosphere, and therefore in the rainwater. Luo et al (2007) found out that, annually, autumn rainfall was lowest, but that the highest concentrations of TP and NO 3 -were present in the rainfall during this season. The results of the present study also reveal that TN and TP are inversely proportional to the amount of precipitation (Fig.…”

“…There is currently no industrial or domestic wastewater input into the West Lake. It has been reported that exogenous sources such as the effluent of rivers, atmospheric precipitation, and runoff have heavily influenced the water quality of the lakes and dam reservoirs (Luo et al 2007;Pang et al 2008;Wilson and Weng 2010;Zhao et al 2011;Bayram et al 2012;Li et al 2012;Elci and Selcuk 2013). For example, Li et al (2012) reported that nitrogen and phosphorus loads from the runoff accounted for 17 and 13 % of the TN and TP inputs to the Moshuihu Lake, Wuhan City, China.…”

“…For example, Li et al (2012) reported that nitrogen and phosphorus loads from the runoff accounted for 17 and 13 % of the TN and TP inputs to the Moshuihu Lake, Wuhan City, China. Another study conducted in the Taihu Lake, Jiangsu Province, China, showed that TN and TP contributed by the wet deposition accounted for about 7.3 and 16.5 % of the annual TN and TP inputs that occur via inflow rivers (Luo et al 2007). Furthermore, Pang et al (2008) revealed that increased input pollution was the main cause of the water quality degradation in the Taihu Lake.…”