Preliminary study on production of periphytic algae of Baoan Lake

A large amount of periphytic algae were found on the stems and leaves of submersed vegetation. The main submersed vegetation in the main lake region and Qiaodunhu region is Potamogeton maackianus, and in the Biandantang region they were Myriophyllum spicatum and Ceratophyllum demersum. In the main lake region and Qiaodunhu region, the production of periphytic algae attached on P. maackianus reached maximum in summer and minimum in winter. In Biandantang region, the production of periphytic algae on a gram of M. spicatum (mgO-2 cntdot gB-M-1 cntdot d-1) was higher in autumn and spring (7.60, 7.12) and lower in winter and summer (5.20, 4.82). In the main lake region the annual average daily production of periphytic algae on the five kinds of macrophytes were 10.29, 7.21, 3.99, 2.61, 0.24 (mgO-2 cntdot gB-M-1 cntdot d-1) for M. specatum, C. demersum, P. maackianus, P. crispus, V. spiralis. The periphyton communities for M. spicatum, P, maakianus, M. spicatum C. demersum developed well and their metabolism ratio was 1.93, 2.62, 2.50 respectively, which were similar to that of the plankton community and all belonged to the typical autotrophic metabolism. The metabolism ratio of the periphyton community attached on V. spiralis was far lower than 1.0 indicating the heterotrophic metabolism. The annual net productions per area of periphytic algae in the main lake region, Qiaodunhu region, Biandantang region were 1.42, 1.15, 1.91 times of macrophytes and were 8. 95, 5.86, 5.52 times of planktonic algae. The annual P/B coefficients of the periphytic algae attached on the P. maackianus in Qiaodunhu region and the main lake region were 65 and 111 respectively. In Biandantang region the annual P/B coefficient of the periphytic algae attached on the M. spicatum and C, demersum were 190 and 256 respectively.