太湖北部不同湖区春、夏季溶解性酸性多糖分布

为研究太湖dAPS(dissolved acidic polysaccharides,溶解性酸性多糖)的时空变化,探讨湖泊水体中dAPS对有机碳的贡献和重要性,于2012年春、夏季调查了太湖北部不同湖区(竺山湾、梅梁湾、贡湖湾、湖心区)水体中ρ(dAPS),分析了其时空变化特征及其与ρ(Chla)之间的关系,并探讨了不同湖湾中dAPS对DOC(溶解性有机碳)的贡献率. 结果表明,太湖北部水体中ρ(dAPS)春、夏季变化范围为3.02~9.93mg/L,平均值为(6.10±1.59) mg/L. 夏季太湖北部各湖区之间ρ(dAPS)没有显著性差异,春季梅梁湾中ρ(dAPS)显著高于湖心区(P<0.05),其他湖区并没有显著性差异. 春、夏两季ρ(dAPS)的最低值均出现在湖心区. 除贡湖湾外,夏季太湖北部各湖区ρ(dAPS)与ρ(Chla)都存在显著线性正相关,而春季各湖区则无显著线性关系. 这说明春、夏季dAPS的受控因素不一样,夏季ρ(dAPS)受藻类影响较大. 夏季各湖区dAPS对DOC的贡献率以贡湖湾最高,平均值高达46.7%±7.7%,春季则以梅梁湾的贡献率较高,平均值为68.6%±5.9%,这意味着dAPS在太湖水体有机碳循环中起着重要的作用. 

Study on the Dissolved Acidic Polysaccharides at Different Lake Areas in the Northern Lake Taihu in Spring and Summer

Dissolved acidic polysaccharides (dAPS) were presumed to be the precursors of transparent exopolymer particles (TEP) (i.e., a special gel-like matter in the waters), and played an important role in the cycling process of elements and organic carbons in the waters. However, there was little research on dAPS temporal-spatial distribution. In order to fill this gap, the aims of this study are:1) to investigate the distribution of content of dAPS in the northern Lake Taihu, 2) to analyze the variation of contents of dAPS in different lake areas (Zhushan Bay, Meiliang Bay, Gonghu Bay and Lake Centre) in the northern Lake Taihu, 3) to explore the correlation between contents of dAPS and Chla), and 4) to demonstrate that dAPS are a significant organic carbon pool in lake waters. Based on the measured data in the spring and summer of 2012in the northern Taihu, the range of contents of dAPS in northern Lake Taihu from spring to summer was 3.02-9.93mg/L, with the mean value (6.10±1.59) mg/L. The mean values contents of dAPS in bays were higher than contents of dAPS those in Lake Centre in both spring and summer. However, there was no significant difference among the contents of dAPS of four lakes areas in summer. In contrast, in spring the content of dAPS ((7.47±0.73) mg/L) in Meiliang Bay was significantly higher than that at Lake Centre ((4.86±1.00) mg/L) (P<0.05). There was a significant positive correlation between contents of dAPS and Chla at four areas except for Gonghu Bay in summer. However, there was not a significant correlation in spring for all areas. This result suggested that the content of dAPS in summer was mostly affected by phytoplankton. Furthermore, the contribution rate of dAPS as carbon to DOC with mean value 46.7%±7.7% was highest in Gonghu Bay in summer, and the mean value 68.6%±5.9% was higher in Meiliang Bay in spring, indicating that dAPS are a significant pool of organic carbon in lake waters.