Recovery and Comprehensive Control of Aquiculture Aquatic Environment by Beneficial Microbes (I)
Technical Director of Beijing Ming Ri Da Science and Technology Development Co., Ltd. Master of Science in Pharmacology and Toxicology, China Agricultural University Li Shuyou Fish and shrimps, etc. The growth, survival and living of aquatic animals must depend on the water environment. In recent years, with the development of aquaculture intensive and semi-intensive culture models in China, the degree of intensification has been increasing, and the self-pollution of water bodies is serious, and the ecological environment of aquaculture has become increasingly deteriorating. China's aquaculture production is basically a method of aquaculture, which does not discharge sewage. In particular, a feeding-based breeding mode, eutrophication factors such as baits, feces, and aquatic animals and plants are coexistent in a single body of water, combined with water pollution and ponds. The decrease of self-purification and regulation capacity has caused serious over-standards such as chemical oxygen demand (COD), biological oxygen demand (BOD), ammonia nitrogen, nitrite, and sulfide in aquaculture water, and the number and types of pathogenic microorganisms have increased, resulting in worsened culture. The environment has caused fish and shrimp disease to occur frequently, which has brought great harm to aquaculture production. Therefore, how to take effective measures to maintain a good pond ecological environment and promote the healthy growth of aquaculture animals under the premise of the existing breeding mode is an important part of the sustainable development of the aquaculture industry. 1. The beneficial effect of beneficial microorganisms on the aquaculture environment 1.1 The status and role of beneficial microorganisms in the circulation of aquaculture waters The aquaculture water system, as an ecosystem, is constantly undergoing a complex material cycle. Aquatic plants, mainly phytoplankton, absorb inorganic nutrients and carbon dioxide from the water, use solar energy for photosynthesis, synthesize organic matter, and release oxygen to grow and reproduce. Zooplankton, zoobenthos, and some species of fish and shrimp can grow and multiply with phytoplankton feed. The beneficial microorganisms decompose and mineralize residual baits, feces, and aquatic plants by oxidizing, reducing, photosynthesis, assimilation, and alienation, transforming from complex organic matter into simple inorganic substances for phytoplankton growth and reproduction, and purifying the environment. Ensure the normal function of water quality, thus maintaining the ecological balance of the aquaculture environment (see Figure 1). In this complex material cycle, beneficial microorganisms act by affecting the carbon cycle, nitrogen cycle, phosphorus cycle, sulfur cycle, and the like. During the carbon cycle (Figure 2), beneficial microorganisms decompose organic matter, release CO2, and build a complex organic matter of their own tissues through the photosynthesis of phytoplankton, providing O2 and polysaccharides for zooplankton, benthic animal, fish and shrimps. In the nitrogen cycle (Fig. 3), beneficial microorganisms convert ammonia-nitrogen (NH3-N) and water in the water under conditions rich in dissolved oxygen through ammoniation, digestion, denitrification, and nitrogen fixation. The toxic ammonia nitrogen, such as nitrate (NO2-), is converted to nitrate nitrogen (NO3-), which is used by algae to purify water quality; (follow-up)