The Model Of Carbon Flux In Invensive Peaeid Shrimp Culture And Ecological Cultivation

As the development of shrimp culture and Low-carbon economy, people take more and more concern about how to mitigate both the waste nutritional matters and environmental impacts of effluent discharge from shrimp pond. The field works were carried out both in Zhoushan ZheJiang Province and Qingdao ShanDong Province from Apr. to Nov. , 2009 and Apr. to Oct. , 2010 to understand the basic physical, chemical and biological process between intensive penaeid shrimp culture and ecological cultivation. The Ecopath and Ecosim models were built up to find the approaches in efficiently transfer the waste matters in intensive penaeid shrimp culture and ecological cultivation. The present study aims to investigate the ecosystem characters in both cultures in order to find a way to make the shrimp culture more effective and environmentally friendly. The main results were shown as follows:1. Primary ecological characteristics of the physical and chemical environment and the characteristic of biocoenosis in intensive penaeid shrimp cultureAlthough with higher stocking density of 150 ind/m2, the shrimp growth was not limited by any of the water quality parameters, including temperature, salinity ,DO and pH. DOC and POC in water and TOC in sediment increased with the progress of rearing. The income of organic carbon in shrimp ponds mainly includes phytoplankton production and feeds. The phytoplankton community was singleness during the culture. The picophytoplankton (<10μm) took the domination position not only in biomass(76%) but also in production(64.6%);The biomass of zooplankton steadied decline during the shrimp culture period . The biomass of zooplankton was highest in early days of shrimp culture period. It declined because the regulation of food intake by shrimp. The changes of biomass and daily respiration of zooplankton were alike; The biomass of pelagic bacteria in water ranged from 1.69 to 11.8gC/m2. The changes of daily production and respiration of pelagic bacteria were the same to the change of biomass, The biomass of sediment bacteria was increased slowly during shrimp culture period expect the last 15 days. The change rules of daily production and respiration of sediment bacteria were the same to the change of biomass; The weight and the length of cultured shrimp were increased during shrimp culture period, The organic carbon of shrimp obviously negatively correlated with time.2. Primary ecological characteristics of the physical and chemical environment and the characteristic of biocoenosis in ecological cultivationThe shrimp growth was not limited by any of the water quality parameters, including temperature, salinity, DO and pH with lower stocking density of 15ind/m2. DOC and POC in water and TOC in sediment increased with the progress of rearing. The biomass of phytoplankton was different on difference levels during shrimp culture period. The microphytoplankton (<15μm) took the domination position not only in biomass(65%) but also in production(69%);There was not obvious regular in the change of the biomass of zooplankton. The change regularity of biomass was different between the marozooplankton and microzooplankton. The difference may be caused by the habit of shrimp feeding on different kinds of food. The daily respiration of zooplankton and the biomass were alike; The biomass of pelagic bacteria and sediment bacteria went up steadily during shrimp culture period. The daily production and respiration had a linear relationship with water temperature according to regressive analyses. The weight and the length of cultured shrimp were increased during shrimp culture period. The organic carbon of shrimp had a little difference but it was negatively correlated with time.3. Ecopath model based structure and function of intensive penaeid shrimp culture and ecological cultivationThe transfer efficiency of intensive penaeid shrimp culture ecosystem was low because of its simple ecosystem. The ecotrophic efficiency of marozooplankton. diets and detritus (water) were 0.527 0.726 and 0.885 while others were much lower than 0.5. The utilizing efficiency of ecosystem was very low. The production of groups was wasted instead of be used by the ecosystem; The structure of ecological cultivation was more complex than intensive penaeid shrimp culture. The transfer efficiency was high. There were only three groups which were microzooplankton(0.494),sediment bacteria(0.237) and benthic dertritus(0.492) with low ecotrophic efficiency while others were much higher than 0.5. It implied that the utilizing efficiency of ecosystem was high. The productions were used by the ecosystem. With the help of mixed trophic impact (MTI ) in Ecopath, the best avenue was found to not only increase the output of shrimp but also make the environment more clean. Increasing the biomass of marozooplankton will be useful to increase the output of shrimp in intensive penaeid shrimp culture. Increasing the biomass of helpful germs will be much better to improve the ecotrophic efficiency of the system; There is a little difference in ecological cultivation. Increasing the biomass of chironomid larvae will be helpful to increase the ecotrophic efficiency of microzooplankton. sediment bacteria and benthic dertritus.