太湖春季藻类生长的磷营养盐阈值研究

为了探讨太湖春季藻类生长的磷营养盐阈值,采用原位营养盐富集生物模拟实验,研究了太湖梅梁湾浮游植物对不同浓度无机磷(PO43--P)的生长响应.结果表明:外源磷添加能显著的促进浮游植物生长,但存在阈值.当磷浓度低于0.02mg/L时,藻类生长速率和生物量是可控的,当磷浓度高于0.02mg/L时,生长速率和生物量没有变化,因此春季藻类生长的无机磷阈值为0.02mg/L,相当于总磷阈值为0.059mg/L.太湖目前只有部分湖区总磷年平均浓度处于总磷阈值以下,控制流域的磷负荷,降低太湖的浮游植物生物量将是一个长期过程.

Developing the critical phosphorus threshold for spring algal growth in Lake Taihu,China

In order to establish a phosphorus threshold for phytoplankton growth in Tai Lake (Taihu) in spring, a in situ nutrition enrichment experiment was conducted in highly eutrophic Meiliangbay to examine the growth response of phytoplanktonto different concentration of inorganic phosphorus (PO43--P).The results showed that exogenous phosphorus (P) enrichment could promote phytoplankton growth, and that it exhibited threshold characteristics. Phytoplankton growth rate and biomass would be controlled at P addition levels of less than 0.02mg/L.When the P concentration exceeded 0.02mg/L,the growth rate and biomass remained constant. Therefore, the inorganic P threshold value for algal growth is 0.02mg/L in spring, which equivalent to 0.059mg/L of the TP threshold value.