Environmental heterogeneity analysis, assessment of trophic state and source identification in Chaohu Lake, China

Abstract

Hierarchical cluster analysis (CA) grouped the 12 sampling sites into two clusters (Eastern Chaohu Lake and Western Chaohu Lake). Temporal CA classified the 12 months into four periods (March-May; June-August; September-November; January, February and December) with a distinct regular seasonal cycle in Eastern Chaohu Lake and four periods (January-April and December; May, July and November; June, September and October; August) with an irregular seasonal cycle in Western Chaohu Lake. Trophic state index analysis showed that Eastern Chaohu Lake was in mesotrophic levels, while Western Chaohu Lake was in eutrophic and hypereutrophic levels. Based on pollutant source statistics data, the dominant pollution sources were identified as domestic sewage and non-point pollution in Eastern Chaohu Lake. Domestic sewage, industrial and non-point sources were contributed to eutrophication in Western Chaohu Lake.

Shifts between ammonia-oxidizing bacteria and archaea in relation to nitrification potential across trophic gradients in two large Chinese lakes (Lake Taihu and Lake Chaohu)

“…Eutrophication is a serious environmental problem for both Lake Taihu and Lake Chaohu. The trophic state of both lakes has been extensively investigated (Cai et al, 2012;Guang-wei, 2008;Jiao et al, 2006;Shang and Shang, 2007;Yu et al, 2011) using the Trophic State Index (TSI) developed by Carlson (1977) and revised by Aizaki (1981). Based on these studies, Lake Taihu can be divided into the following three parts according to the trophic state: (1) its North Bays (Meiliang Bay and Zhushan Bay) are in eutrophic to hypertrophic states; (2) much of the open areas (Central region and Western region) and Gonghu Bay are in mesotrophic to eutrophic states, and (3) the East Bays are mainly in the mesotrophic state; Similarly, Lake Chaohu can be divided into two parts from the Zhongmiao Temple to Qitouzui Cape, with the western part in a eutrophic to hypertrophic state and the eastern part in a mesotrophic state.…”

“…Based on the literature (Cai et al, 2012;Guang-wei, 2008;Jiao et al, 2006;Qin, 2008;Shang and Shang, 2007;Wu et al, 2007;Yu et al, 2011;Zhang et al, 2007) and our own chemical data (Table 1), the sites could be divided into two categories. One of these was in eutrophic state (type E) and the other was the mesotrophic state (type M).…”

Assessment of Reservoir Water Quality Using Multivariate Statistical Techniques: A Case Study of Qiandao Lake, China

“…CA is an unsupervised pattern recognition approach for classifying categories according to the nearness or similarity [25]. The classified categories present strong internal homogeneity and strong external heterogeneity [26]. CA utilizes a wide variety of algorithms, among which hierarchical agglomerative technique is most widely used, where a data set can be sequentially classified into categories by selecting the most similar variable pairs and generating categories in a stepwise way [27].…”

AVALIAÇÃO ESPAÇO-TEMPORAL DA CLOROFILA a E DO ÍNDICE DE ESTADO TRÓFICO NO RIO PIRACICABA, SÃO PAULO, BRASIL

“…Tais problemas para o ambiente aquático, associados à eutrofização fizeram com que este assunto fosse tratado com mais atenção (YU et al, 2011), e desta forma com o tempo muitos métodos foram sendo desenvolvidos para avaliar o estado trófico dos ambientes aquáticos (PAERL, 2009;PRIMPAS e KARYDIS, 2010;DEVLIN et al, 2011;FERREIRA et al, 2011). A partir dessas metodologias, vários estudos começaram a ser desenvolvidos com o objetivo de determinar o IET de ecossistemas aquáticos (ZANINI et al, 2010;YU et al, 2011;ALVES et al, 2012;YANG et al, 2012).…”

“…A partir dessas metodologias, vários estudos começaram a ser desenvolvidos com o objetivo de determinar o IET de ecossistemas aquáticos (ZANINI et al, 2010;YU et al, 2011;ALVES et al, 2012;YANG et al, 2012). Carlson (1977) desenvolveu uma classificação do estado trófico dos ambientes aquáticos baseado em três tipos de parâmetros: concentração de clorofila a, transparência da água medida pelo disco de Secchi, e concentração de fósforo total.…”