藻—溞系统对凡纳滨对虾养殖水体调控效果的研究

取5000 mL灭菌后的凡纳滨对虾养殖尾水于5000 mL高压灭菌的烧杯中,分为10组,分别为蛋白核小球藻组(C1)、蛋白核小球藻+大型溞组(C2)、衣藻组(C3)、衣藻+大型溞组(C4)、隐藻组(C5)、隐藻+大型溞组(C6)、蛋白核小球藻+衣藻组(C7)、蛋白核小球藻+衣藻+大型溞组(C8)、衣藻+隐藻组(C9)、...

Effects of Algae-Daphnia Systems on Regulation of Effluent from Pacific White Shrimp Litopenaeus vannamei Culture and Growth of Microalgae and Water Fleas Daphnia magna

A total of 5000 mL of sterilized water in Pacific white shrimp Litopenaeus vannamei rearing ponds was held in a 5000 mL autoclaved beaker, divided into 10 groups, and inoculated with various combinations of algae and water fleas Daphnia magna with initial alga inoculation density of 1×10 ⁸ cell/mL and water fleas density of 1 individual/L , namely, Chlorella pyrenoidosa group (C1), C. pyrenoidosa + D. magna group (C2), Chlamydomonas sp. group (C3), Chlamydomonas sp. + D. magna group (C4), Cryptomonas obovat group (C5), C. obovat + D. magna group (C6), C. pyrenoidosa + Chlamydomonas sp. group (C7), C. pyrenoidosa + Chlamydomonas sp. + D. magna group (C8), Chlamydomonas sp. + C. obovat group (C9), and Chlamydomonas sp. + C. obovat + D. magna group (C10), with 3 parallel groups. The pH value, and contents of dissolved oxygen (DO), total nitrogen (TN), ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total phosphorus (TP) and chlorophyll a were measured every 3 days to investigate the effect of the combined system on the purification of the water in Pacific white shrimp culture and growth of both the shrimp and the algae. It was found that both microalgae and D. magna grew normally in the treatment groups, with good water purification effect of the alga-water fleas combination system, and in particular, the removal rates of 82% for nitrate, 77% for nitrite and 99% for ammonia nitrogen at the end of the experiment. There was poor growth rate in polycultured microalgae than that in monoculture microalgae, with the maximal relative growth rates of 27.7% in C. pyrenoidosa and 26.9% in Chlamydomonas sp.. C. pyrenoidosa was the most favorable for the growth and reproduction of D. magna which was increased from 5 to 88 in number at the end of the experiment, followed by Chlamydomonas sp. (80) and C. obovata (59). In the early stage of culture, D. magna promoted the growth of microalgae, and later prevented the excessive propagation of microalgae, so as to maintain the stability of beneficial algae phase for a long time due to the increase in number of water fleas feeding pressure. Thus, inoculation of C. pyrenoidosa , Chlamydomonas sp. and D. magna were beneficial to the regulation of aquaculture water environment and to maintain the stability of microalgae phase.