The Planktonic Algae Composition Characteristics And Algae Growth Potential In Yangzhou Baoying Lake

Baoying Lake is a shallow, enclosed wetland lake with a total area of about 2152 hm2, located in Baoying County of Jiangsu Province. The biodiversity is rich in Baoying Lake and "Yangzhou Baoying Lake National Wetland Park" is formally built approved by the State Forestry Administration in 2011. In recent years, lake pollution is aggravated and cosystems threatened seriously due to quantities of artificial farming reclamation and sewage disposal. We should investigate planktonic algae in Baoying Lake and collect the biodiversity background data in order to provide basic information for the protection of Baoying Lake biodiversity.This paper from September 2012 to April 2014, in the five investigation cross-section,we carry five times sampling analyzed the composition of planktonic algae species through the sampling survey in spring and autumn respectively. Survey results showed that:there were 85 algal species, belong to eight phylum, with 34 species of green algae,26 species of diatoms and13 species of blue-green algae. Among them, green algae and diatoms are the main categories in Baoying Lake.3-year evaluation value surveys showed that the contents of chlorophyll a (Chla) was generally at a low level with the average of 2.2μg/L. Average Shannon-Weaver diversity index (H’) of whole lake was greater than 3. It indicated that the lake was in less polluted. Pielou evenness index (J’) are generally greater than 0.5. It showed that the distribution of each species is even and the pollution level is light.To assess the risk of algal blooms, we carried out research about algal growth potential (AGP) of Baoying lake. To predict the impact of further nutrient infusion on phytoplankton, carried out adding nitrogen (N) and phosphorus (P) on the impact of the experiment Baoying Lake AGP.Results showed that the maximum yield (MY) was 1.52×106/mL, the maximum specific rate (MSR) was 0.53/d, with adding 0.75 mg/L nitrogen. When 0.05 mg/L phosphorus was added, MY and MSR were 0.61×106/mL and 0.31/d respectively. The MY and MSR of adding nitrogen (0.75 mg/L) were two times than adding phosphorus (0.05 mg/L). It indicated that the increase of nitrogen level could cause algae proliferate in water body of Baoying Lake. The AGP result of Cyanobacteria Anabaena showed that added nitrogen or phosphorus has little feeect on AGP,which also showed the nitrogen is Baoying lake limiting nutrients. These results suggest that future management, we should pay attention to the discharge of nitrogen into bodies of water, avoid water bloom.