Study On The Production Of Plankton And The Carrying Capacity Of Jellyfish In Pond

From June to September of 2008 and May to October of 2009, the primary production, zooplankton production, copepoda production microzooplankton production; the predation rate of jellyfish to different natural food and the transformation efficiency were studied. The results are as follows:1 Study on the primary production of phytoplankton in the jellyfish pond:The primary production of phytoplankton in the jellyfish was measured with black-white bottles method. The average of primary production in the jellyfish pond in 2008 was 7.15±1.36gO2/(m2·d). The average of primary production reached the maximum value (13.59±4.23)gO2/(m2·d) in August and it reached the minimum value(2.52±0.55)gO2/(m2·d) in Octember. The average concentration of chlorophyll in the jellyfish pond in 2008 was 5.99±0.42μg/L. In August the average of chlorophyll reached the maximum value (8.46±0.40μg/L) and in September it reached the minimum value (4.16±0.17μg/L). The average concentration of chlorophyll in the jellyfish pond in 2009 was 10.01±1.81μg/L, and the average of chlorophyll in the sea was 1.79±0.27μg/L. The regress analysis showed that there was close correlation between chlorophyll and primary production.2 Study on the compositon and production of zooplankton and the transformation efficiency:The compositon and production of zooplankton in the pond of Jinghai Bay were measured, so did the transformation efficiency from primary production to secondary production. The results showed that zooplankton was mainly composed of Tortanus derjugini during the experiment both in the jellyfish pond and the sea. The abundance of T.derjugini was from 9.99 to 36.49ind/L in the pond and from 8.80 to 133.60ind/L in the sea. In 2008, the average secondary production of zooplankton was 368.38 mgC/(m2·d), and the secondary production of zooplankton varied from 306.38 to 484.50 mgC/(m2·d). The average transformation efficiency from primary production to secondary production was 31.31% and the transformation efficiency was from 9.29% to 69.66%. In 2009, the average secondary production of zooplankton was 209.60 mgC/(m2·d), and the secondary production of zooplankton varied from 118.85 to 300.66 mgC/(m2·d). The average transformation efficiency from primary production to secondary production was 16.47% and the transformation efficiency was from 5.88% to 55.90%.3 Study on the production of copepoda in the jellyfish pond:The study of production of copepoda in the jellyfish pond based on the result of variation of copepoda biomass in 2009. The secondary production of copepoda in the jellyfish pond and the sea were measured by cumulative growth method. The biomass of copepoda in the jellyfish pond varied from 28.30 to 114.42μg/L and the average was 74.72μg/L. The secondary production of copepoda in the jellyfish pond varied from 7.49 to 20.47 mgC/(m2·d) and the average was 11.96mgC/(m2·d); The average value of P/B was 0.469. The biomass of copepoda in the sea varied from 27.62 to 555.98μg/L and the average was 193.88μg/L. The secondary production of copepoda in the sea varied from 4.95 to 119.90mgC/(m2·d) and the average was 43.05mgC/(m2-d); The average value of P/B was 0.556.4 Study on the Microzooplankton Grazing and Productivity in Jellyfish Pond in Jinghai Bay:The phytoplankton growth, the microzooplankton grazing rates, the grazing pressure on phytoplankton standing stocks and the grazing pressure on potential primary productivity were investigated by the dilution method in jellyfish pond in Jinghai Bay from August to October in 2009. The results showed that the microzooplankton were mainly composed of Tintinnopsis radix during the culturing season, and the abundance of Tintinnopsis radix was from 600 to 2600 ind/L. While the microzooplankton were mainly composed of Tintinnopsis radix, Leprotintinnus nordquisti and Codonellopsis mobilis after the fishing season, and the abundance of them was from 1500 to 6000 ind/L. The growth rates of the phytoplankton varied from 0.05 to 1.03d-1. The grazing mortality rates ranged from 0.24 to 2.37d-1. The grazing pressure of the microzooplankton on phytoplankton standing stocks and potential primary productivity varied from 21.10% to 90.61% and 77.08% to 583.68%, respectively. The secondary productivity of the microzooplankton as a percentage of daily primary productivity was 22.92% to 76.92%. These results indicated that the microzooplamkton played an important role in energy flux and material flow in the ecosystem of the jellyfish pond.5 Study on the carrying capacity of jellyfish in the jellyfish pond:The predation rate of jellyfish to different natural food increased with the growth of density of natural food. It was found that Artemia sp, Moina mongolica and Tortanus derjugini were used as a natural food for jellyfish. The transformation efficiency from natural food to jellyfish varied from 699.4% to 947.62% and the group with Tortanus derjugini was 947.62%. The daliy growth rate of jellyfish varied from 10.42% to 11.96% and the group with Moina mongolica was 11.96%. The carrying capacity of jellyfish in the experimental pond was about 6.38x106kg. The carrying capacity of jellyfish provided by zooplankton in the experimental pond was 6.01×106kg, and that provided by copepoad in the sea was 3.69×105kg.