Fungicide for in-situ treatment of enteromorpha in open sea area, and preparation method and application thereof

Abstract

The invention discloses a microbial agent for in-situ treatment of enteromorpha in an open sea area as well as a preparation method and application of the microbial agent. The microbial agent is naturally formed by fermentation of a composite flora under a proper condition, and the pH value of the microbial agent is less than 4.0; the composite flora comprises bacillus subtilis, nitrifying bacteria, actinomycetes, filamentous bacteria, photosynthetic bacteria, lactobacillus plantarum, saccharomyces cerevisiae, candida, lactobacillus paracasei and bacillus megatherium, and can be applied to differential in-situ treatment of enteromorpha in different scenes (beaches, sea floats and cabins) in open sea areas. The microbial agent is an ecological treatment microbial agent, an acidity chemical regulator is not added, the enteromorpha prolifera in the open sea area can be treated in situ in a strong mode within a short time, and no negative influence is caused to seawater and the marine environment.

Description

Technical Field

[0001] The present invention relates to the technical field of enteromorpha control, and in particular to a bacterial agent for in-situ control of enteromorpha in open sea areas, a preparation method thereof, and applications thereof. Background Art

[0002] In recent years, Qingdao's coastal waters and coastline have been plagued by a massive bloom of Enteromorpha. Although non-toxic, its proliferation can block sunlight, hindering the growth of algae and other organisms on the seafloor. It can also drift onto beaches, impacting tourism. Currently, drifting Enteromorpha is salvaged ashore by ship for harmless disposal or resource recovery. Stranded Enteromorpha on beaches is collected by forklift and transported to landfills or resource recovery, both requiring significant labor and resources. Furthermore, in some areas, chemical treatments are used to control floating Enteromorpha. While these agents can kill the Enteromorpha, they also cause some damage to the marine environment.

[0003] In addition, CN 114938753 A discloses a method for preventing and controlling the harm of mangrove Enteromorpha, which adopts acetic acid solution, natural enemy control and planting Enteromorpha competing plants to prevent and control the harm of mangrove Enteromorpha. CN103409320A discloses a bacterial microbial purifier, which can be used to solve the pollution problems such as purifying urban rivers, fish ponds, grape wine wastewater, Enteromorpha degradation, solid waste deodorization, and seawater oil spills, but its method of use is unclear and the implementation effect is not reflected. CN110002611A discloses an aquaculture water regulator, and CN109231495A discloses an algae control microbial preparation, both of which purify the water body by decomposing nutrients such as nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, chemical oxygen demand, and active phosphate in the aquaculture water body through microorganisms, and the processing time of patent CN109231495A takes 20 days. CN106967655A discloses an algae phase regulator, primarily used to regulate the content of cyanobacteria, green algae, diatoms, and other algae in aquaculture ponds, requiring more than five days of regulation. None of the aforementioned related patents are suitable for in-situ treatment of Enteromorpha in open waters. Furthermore, currently available Enteromorpha decomposing agents generally have poor acid resistance, with a pH range of 5.0-8.0. The shelf life of Enteromorpha decomposing agents is typically around one month, resulting in a short storage period.

[0004] Therefore, it is very necessary to develop a microbial agent suitable for in situ control of Enteromorpha in open waters without causing harm to the marine ecology, as well as a biological in situ control method for rapid control of Enteromorpha landed on the shore and drifting at sea, so as to achieve all-round control of Enteromorpha in offshore open waters. Summary of the Invention

[0005] Current approaches to controlling Enteromorpha in the ocean are ineffective, primarily relying on salvage and disposal. Existing chemical methods for clearing Enteromorpha from open waters severely damage the marine environment. Most microbial agents currently on the market suffer from poor acid resistance, a pH range of 5.0-8.0, and a short shelf life of around one month. Furthermore, publicly available microbial agents for controlling Enteromorpha or contaminated waters are unsuitable for efficient in-situ control of Enteromorpha in open waters.

[0006] In this regard, the present application is based on the idea of ​​spraying microbial agents on the surface of fresh floating Enteromorpha in the open sea to locally change the growth environment of Enteromorpha and cause damage to Enteromorpha cells, thereby killing Enteromorpha, and then efficiently and quickly decompose the dead Enteromorpha in a short period of time so as not to cause secondary pollution, thereby achieving in situ efficient treatment of Enteromorpha floating in the open sea. A microbial agent for in situ treatment of Enteromorpha in open seas, as well as its preparation method and application are proposed.

[0007] This application achieves the above objectives through the following technical solutions:

[0008] The present application discloses a microbial agent for in-situ treatment of Enteromorpha in open sea areas, comprising a composite microbial agent with a pH value of less than 4.0 naturally formed by fermentation of a composite bacterial community.

[0009] Furthermore, a method for preparing a microbial agent for in-situ treatment of Enteromorpha in open seas comprises the following steps:

[0010] (1) 16 mg of Bacillus subtilis, Lactobacillus plantarum, Lactobacillus paracasei, and Bacillus megaterium in a weight ratio of 8:3:3:2 were added to a container containing 50 g of glucose, 30 g of peptone, 10 g of beef extract, and 5 L of distilled water, and the mixture was stirred and cultured on a constant temperature shaker at 25-35° C. for 12 hours;

[0011] (2) Add 9 mg of brewer's yeast and Candida in a weight ratio of 6:3, 20 g of malt extract, and 10 g of glucose to the above container and continue stirring at constant temperature for 6 hours;

[0012] (3) 10 mg of actinomycetes and filamentous fungi in a weight ratio of 8:2, 40 g of mashed potatoes, and 15 g of urea were added to the above container and stirred at a constant temperature for 6 hours;

[0013] (4) 5 mg of nitrifying bacteria and photosynthetic bacteria in a weight ratio of 1:4, 5 g of NaNO2, and 15 g of yeast extract were added to the above container and stirred at a constant temperature for 48 hours until the composite bacterial community stabilized;

[0014] (5) The composite bacterial community and an appropriate amount of potato residue were fully mixed and added to a fermentation tank, and an appropriate amount of sterile water was added. At 25-35°C, sterile air was continuously introduced and stirred for 7-10 days to complete the preparation of a composite microbial agent with a pH less than 4.0.

[0015] By adopting the above technical solution, the photosynthetic system of Enteromorpha is effectively affected when the environmental pH is less than 4.5, which is mainly manifested as damage to the cell membrane system, destruction of chloroplast structure and thylakoids, increased permeability of the biofilm, resulting in separation of the cell wall and ultimately leading to the death of Enteromorpha cells. Therefore, the selection of actinomycetes, Bacillus subtilis, Lactobacillus plantarum, Bacillus megaterium, etc. to produce organic acids can effectively lower the pH value of the inoculum. Bacillus subtilis can adsorb on the surface of Enteromorpha plants and produce lytic substances, causing Enteromorpha plants to break, disintegrate or cytoplasm to dissolve. Secondary metabolites can also dissolve Enteromorpha cell walls, leading to cell wall perforation, etc.; Candida can produce aspartyl proteases to degrade the extracellular matrix, causing damage to Enteromorpha cells, effectively destroying the cell structure of Enteromorpha and causing Enteromorpha cell death. After the Enteromorpha cells die, various enzymes (such as proteases, amylases, and cellulases) produced by actinomycetes and large amounts of chitinase secreted by Bacillus subtilis decompose organic matter and toxic and hazardous substances in the water, effectively decomposing the dead Enteromorpha. Nitrifying bacteria consume the decaying Enteromorpha cells in the water, producing substances such as ammonia nitrogen and nitrites. Bacillus megaterium degrades organic phosphorus and various toxins. Due to the lack of oxygen in water bodies in areas where Enteromorpha is infested, photosynthetic bacteria can effectively decompose and transform organic matter, sulfide, ammonia, and other substances in the water. Photosynthetic bacteria can also use these substances to propagate themselves and produce nutrients such as proteins, vitamins, growth factors, and immune factors. Meanwhile, brewer's yeast is rich in vitamins and polysaccharides, and actinomycetes also produce substances such as vitamin B12, providing nutrients for bacterial growth. By combining these strains, a composite microbial agent with a pH of less than 4.0 naturally formed by fermentation of the composite bacterial community achieves a synergistic mechanism of destroying Enteromorpha cell structure, decomposing it with complex enzymes, and purifying water.

[0016] By adopting the above technical solution and selecting potato residue as the nutrient source for large-scale fermentation and propagation of the composite microbial agent, the culture cost can be reduced, the preparation method is simple and controllable, and a composite microbial agent with a pH of less than 4.0 can be obtained in a relatively short time.

[0017] The present application also discloses the application of a bacterial agent for in-situ control of Enteromorpha in open sea areas, including differentiated three-in-one in-situ control of Enteromorpha for different scenarios in open sea areas (shore, sea drift, and ship cabins), including in-situ control of Enteromorpha landing on shore and beach, in-situ control of Enteromorpha drifting at sea, and microbial composting control of Enteromorpha drifting at sea on ship cabin platforms.

[0018] Furthermore, the in situ treatment of the Enteromorpha landed on the beach includes spraying the Enteromorpha stranded on the beach with a compound microbial agent at a ratio of 5 to 20 kg per mu after the tide goes out and there is no rainfall. The treatment cycle is about 4 to 8 hours, and the spraying is done 1 to 3 times within the treatment cycle. When the tide rises, the remaining residue is returned to the ocean with the waves.

[0019] In situ microbial control of sea-drifting Enteromorpha includes spraying compound microbial agents at a rate of 10 to 200 kg per mu using drones or boats on large areas of concentrated sea-drifting Enteromorpha or Enteromorpha intercepted by large-scale interception nets in rainless weather. The control cycle is about 3 to 12 hours, with 1 to 3 sprayings within the control cycle. The Enteromorpha will naturally settle after decomposition.

[0020] Microbial composting treatment of drifting Enteromorpha on the cabin platform includes salvaging the scattered Enteromorpha floating on the sea surface to the cabin platform and treating them at a rate of 0.1-0.3 kg / m 3 The salvaged Enteromorpha is sprayed with a composite microbial agent at a ratio of , and sprayed while salvaging. After salvaging, it is left to stand for 12 to 24 hours. After the Enteromorpha is decomposed until the biomass reduction rate is ≥ 70%, it can be thrown into the ocean for natural sedimentation.

[0021] Furthermore, the application of a bacterial agent for in-situ control of Enteromorpha in open sea areas includes a significant increase in the total heterotrophic bacteria count in the surface water within 20 meters of the spraying point, which can last for 48 to 96 hours; during the treatment period, the ammonia nitrogen, nitrate nitrogen and phosphate in the water area 10 to 100 meters around the sea area increase by within 5% to 40%, and can be restored to the pre-spraying level within 6 to 24 hours.

[0022] By adopting the above technical solution and spraying different doses of enteromorpha control bacteria agents, differentiated and targeted control is carried out on the enteromorpha that has landed on the shore, the enteromorpha that is concentrated in a large area and drifted at sea or intercepted by a large-scale interception net, and the enteromorpha that is sporadically floating on the sea surface, thereby achieving a "three-in-one" comprehensive treatment of the enteromorpha disaster; the composite bacteria agent used is an ecological bacteria agent, which only produces very small changes to the water quality of some sea areas in a short period of time during the treatment process, and can restore to the original level in a short time, so it has no negative impact on the sea area and marine ecology.

[0023] Compared with the prior art, the beneficial effects are:

[0024] 1. Ecological and environmental protection of the microbial agent: The microbial agent in this application is an ecological treatment microbial agent. Without adding chemical acidity regulators, various organic acids are generated through the blending and fermentation of the bacterial community, thereby naturally forming a composite microbial agent with a pH of less than 4.0. This is different from "chemical acidification", avoids pollution from chemical reagents, and has no negative impact on the marine ecology.

[0025] 2. Long shelf life: The pH of the bacterial agent of the present application can be maintained at around 3.5, has good acid resistance, and has a long shelf life. It is different from a certain publicly available Enteromorpha rapid-decomposition composite bacterial agent, which has a pH of 5.0-8.5 and a shelf life of only 7 days. The bacterial agent of the present application effectively solves the problems of weak acid resistance and short shelf life of Enteromorpha corrosive bacterial agents on the current market.

[0026] 3. Novel treatment method: The bacterial agent of this application uses a multi-effect synergistic mechanism of "destroying the growth environment + promoting cell damage and death + efficiently decomposing dead Enteromorpha + purifying water quality + mutualistic symbiosis of bacterial communities", etc., and adopts a large number of compounding experiments and has been verified through actual application to effectively treat Enteromorpha. Finally, a bacterial agent suitable for in-situ treatment of Enteromorpha in open waters was obtained, which is different from other treatment methods that achieve water purification and algae control by digesting water nutrients in closed waters. The multi-effect synergistic mechanism of the bacterial agent of this application for treating Enteromorpha can treat Enteromorpha in "hours", which has a subversive advantage compared to the treatment cycle of existing technologies (such as 20 days disclosed in CN109231495A), and the treatment efficiency is significantly improved.

[0027] 4. Diverse application scenarios: To solve the limitation of existing technologies that are "only applicable to static waters", the method of this application can achieve targeted treatment of landed Enteromorpha on the shores of open seas, interception of Enteromorpha concentrated in large areas of sea drifting or large-scale interception nets, and targeted treatment of Enteromorpha floating on the sea surface. It can effectively treat Enteromorpha in open seas and on beaches in a short period of time. Different from methods such as salvaging the Enteromorpha ashore for harmless or resource-based treatment, using natural enemies or competing plants for control, it saves manpower, material and financial resources, is simple and easy to implement, and realizes the "three-in-one" all-round treatment of Enteromorpha in offshore open waters.

[0028] 5. No Negative Environmental Impact: When this microbial agent is used for in-situ treatment of Enteromorpha in open waters, the total heterotrophic bacterial count in the surface waters surrounding the spraying point significantly increases, and the bacterial community can maintain its abundance in the open sea for a long time. During the treatment period, ammonia nitrogen, nitrate nitrogen, and phosphate levels in the surrounding waters only increase slightly and return to pre-spraying levels within 6-24 hours, with no negative impact on the sea area or marine ecology. This is in contrast to the secondary marine pollution and new environmental problems that may be caused by the use of chemical agents to treat Enteromorpha. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1This is a pH value test chart of a bacterial agent for in-situ treatment of Enteromorpha in open sea areas disclosed in this application.

[0031] Figure 2 This is the pH test chart of the bacterial agent produced on July 20, 2023 and tested on March 1, 2024.

[0032] Figure 3 This is a graph showing the change in the remaining weight of Enteromorpha over time after treatment with Enteromorpha control agents of different pH values.

[0033] Figure 4 This is a diagram showing the morphological changes of floating Enteromorpha after adding the Enteromorpha control agent of this application at room temperature in the laboratory.

[0034] Figure 5 The rendering of in-situ treatment of landed Ulva prostrata in open sea areas.

[0035] Figure 6 The rendering of the in-situ treatment of large-scale drifting Enteromorpha in open waters. DETAILED DESCRIPTION

[0036] The following is combined with Figure 1-6 , the technical solution of the present invention is further explained:

[0037] Example 1:

[0038] 16 mg of Bacillus subtilis, Lactobacillus plantarum, Lactobacillus paracasei and Bacillus megaterium in a weight ratio of 8:3:3:2 were added to a container containing 50 g of glucose, 30 g of peptone, 10 g of beef extract and 5 L of distilled water, and stirred and cultured on a constant temperature shaker at 28°C for 12 hours; subsequently, 9 mg of brewer's yeast and Candida in a weight ratio of 6:3, as well as 20 g of malt extract and 10 g of glucose were added to the above container, and constant temperature stirring was continued for 6 hours; subsequently, 10 mg of actinomycetes and filamentous fungi in a weight ratio of 8:2, as well as 40 g of mashed potatoes and 15 g of urea were added to the above container, and constant temperature stirring was continued for 6 hours; subsequently, 5 mg of nitrifying bacteria and photosynthetic bacteria in a weight ratio of 1:4, as well as 5 g of NaNO2 and 15 g of yeast extract were added to the above container, and constant temperature stirring was continued for 48 hours until the composite bacterial community stabilized. Then, the composite bacterial flora and an appropriate amount of potato residue were fully mixed and added to the fermentation tank, and an appropriate amount of sterile water was added. Sterile air was continuously introduced and stirred for 7 days at 28°C to prepare a composite microbial agent with a pH of 3.57 ( Figure 1 ).

[0039] The shelf life of the microbial agent product of this application is 1 year. The product produced on July 20, 2023 was tested on March 1, 2024, and its pH was 3.94, which is still lower than 4.0 ( Figure 2); and the activity of the bacterial agent was normal by observation under a microscope, indicating that it has the advantage of a long storage period.

[0040] Example 2:

[0041] To further verify the difference in the pH of the inoculant on Enteromorpha treatment, Enteromorpha treatment inoculants with different pH values ​​(3.57, 5, and 6) were prepared and the changes in the residual weight of Enteromorpha during the treatment cycle were observed. The following steps were included:

[0042] In a marine environment, 15 kg of Enteromorpha were evenly distributed in each test enclosure (1 square meter). After the experiment began, each test enclosure was evenly sprayed with the same amount of Enteromorpha control agent with different pH values. The enclosures were then removed and weighed 6, 12, and 24 hours after the experiment began.

[0043] Experimental results:

[0044] In the test group of the Enteromorpha control agent at pH 3.57, about 50% of the Enteromorpha settled after 6 hours, and the sedimentation rate of the Enteromorpha slowed down from 6 to 12 hours. After 24 hours, about 80% of the Enteromorpha settled. Compared with the test groups treated with the Enteromorpha control agent at pH 5 and 6, the bacterial agent of the present application can quickly decompose the Enteromorpha and cause it to settle. The sedimentation rate after 24 hours is much higher than that of the test groups at pH 5 and 6. Figure 3 )

[0045] Example 3:

[0046] In order to further verify the effect of the microbial agent treatment, the enteromorpha treatment microbial agent treatment floating enteromorpha test was further verified in the laboratory, including the following steps:

[0047] The fresh seawater and fresh Enteromorpha obtained by sampling were placed in a plastic barrel without any treatment. 50 ml of bacterial agent was added at one time under normal laboratory temperature conditions, and the morphological changes of Enteromorpha in the barrel were observed.

[0048] Experimental results:

[0049] Pour the bacterial agent into the water where Enteromorpha floats. The floating Enteromorpha partially sinks after about 8 hours and decomposes into flocs. After about 12 hours, the Enteromorpha flocs in the water disappear completely (the nutrient decomposition during the cultivation of the bacterial agent turns red, and the color of the water is the color of the bacterial agent carrier. It has passed the non-toxicity test and is harmless to various organisms) Figure 4 ).

[0050] Example 4:

[0051] In order to further verify the effect of the applied microbial agent on the in-situ treatment of landed Enteromorpha on the shore of open sea, a treatment experiment was conducted, including the following steps:

[0052] Prepare a certain amount of Enteromorpha control agent. After the tide goes out and there is no rain, spray the Enteromorpha control agent on the Enteromorpha stranded on the beach at a ratio of 5kg / mu. Spray once in total and continuously observe the changes in the Enteromorpha on the beach.

[0053] Experimental results:

[0054] 45 minutes after spraying the fungicide, the Enteromorpha turned yellow, and the Enteromorpha cells slowly decomposed and died; after 2.5 hours, the Enteromorpha volume decreased and separated from the beach sand; overnight (about 20 hours later), with the rising tide, the decomposed Enteromorpha residues returned to the ocean with the waves, and the Enteromorpha on the beach basically disappeared, and the beach was odorless ( Figure 5 ).

[0055] Example 5:

[0056] In order to further verify the effect of the applied microbial agent on the in-situ treatment of drifting Enteromorpha microorganisms in open sea, a treatment experiment was conducted, including the following steps:

[0057] Prepare a certain amount of Enteromorpha control bacteria agent, and drive a boat to a large area of ​​sea-drifting Enteromorpha in non-rainy weather. The Enteromorpha thickness in this area is about 20 to 25 cm, and the area is about 27 mu. Use the boat to spray the Enteromorpha control bacteria agent on the sea-drifting Enteromorpha at a ratio of 10 kg / mu, spray once during the control period, and continuously observe the changes in the sea-drifting Enteromorpha.

[0058] Experimental results:

[0059] After spraying the fungicide, the Enteromorpha was clearly dispersed; after 3 hours, some Enteromorpha had settled; after about 6 hours, all of it had decomposed and settled. Figure 6 ).

[0060] The above shows and describes the basic principles, main features, advantages, and successful application cases of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention as claimed.

Claims

1. A microbial agent for in-situ control of Enteromorpha in open sea areas, characterized in that: A composite microbial agent with a pH value of less than 4.0 formed naturally through fermentation.

2. The method for preparing a bacterial agent for in-situ control of Enteromorpha in open sea areas according to claim 1, characterized in that: The following steps are involved: (1) 16 mg of Bacillus subtilis, Lactobacillus plantarum, Lactobacillus paracasei, and Bacillus megaterium in a weight ratio of 8:3:3:2 were added to a container containing 50 g of glucose, 30 g of peptone, 10 g of beef extract, and 5 L of distilled water, and the mixture was stirred and cultured on a constant temperature shaker at 25-35° C. for 12 hours; (2) Add 9 mg of brewer's yeast and Candida in a weight ratio of 6:3, 20 g of malt extract, and 10 g of glucose to the above container and continue stirring at constant temperature for 6 hours; (3) 10 mg of actinomycetes and filamentous fungi in a weight ratio of 8:2, 40 g of mashed potatoes, and 15 g of urea were added to the above container and stirred at a constant temperature for 6 hours; (4) 5 mg of nitrifying bacteria and photosynthetic bacteria in a weight ratio of 1:4, 5 g of NaNO2, and 15 g of yeast extract were added to the above container and stirred at a constant temperature for 48 hours until the composite bacterial community stabilized; (5) The composite bacterial community and an appropriate amount of potato residue were fully mixed and added to a fermentation tank, and an appropriate amount of sterile water was added. At 25-35°C, sterile air was continuously introduced and stirred for 7-10 days to complete the preparation of a composite microbial agent with a pH less than 4.

0.

3. The use of the bacterial agent for in-situ control of Enteromorpha in open sea areas according to claim 1, characterized in that: Used for differentiated in-situ treatment of Enteromorpha in different scenarios in open waters (shores, sea drifts, and ship cabins), including in-situ treatment of Enteromorpha microorganisms that have landed on beaches, in-situ treatment of Enteromorpha that has drifted at sea, and microbial composting treatment of Enteromorpha that has drifted at sea on ship cabin platforms.

4. The in-situ treatment of beach-landed Enteromorpha microorganisms according to claim 3, characterized in that: After the tide goes out and there is no rain, spray the Enteromorpha stranded on the beach with a compound microbial agent at a rate of 5 to 20 kg per mu. The treatment cycle is about 4 to 8 hours, and spray 1 to 3 times within the treatment cycle. When the tide rises, the remaining residue will return to the ocean with the waves.

5. The in-situ treatment of marine drifting Enteromorpha microorganisms according to claim 3, characterized in that: In rainless weather, for large areas of drifting Enteromorpha or Enteromorpha intercepted by large-scale interception nets, use drones or boats to spray the drifting Enteromorpha with compound microbial agents at a rate of 10 to 200 kg per mu. The treatment cycle is about 3 to 12 hours, and the spraying is done 1 to 3 times within the treatment cycle. The Enteromorpha will decompose and settle naturally.

6. The microbial composting treatment of sea drift Enteromorpha on a ship cabin platform according to claim 3, characterized in that: The scattered Enteromorpha floating on the sea surface were salvaged onto the cabin platform and the sediment was collected at a rate of 0.1-0.3 kg / m 3 The salvaged Enteromorpha is sprayed with a composite microbial agent at a ratio of , and sprayed while salvaging. After salvaging, it is left to stand for 12 to 24 hours. After the Enteromorpha is decomposed until the biomass reduction rate is ≥ 70%, it can be thrown into the ocean for natural sedimentation.

7. Use of the bacterial agent for in-situ control of Enteromorpha in open sea areas according to claims 3-6, characterized in that: The total number of heterotrophic bacteria in the surface water within 20 meters of the spraying point increased significantly and could last for 48 to 96 hours.

8. The use of a microbial agent for in-situ control of Enteromorpha in open sea areas according to claims 3-6, characterized in that: During the treatment period, ammonia nitrogen, nitrate nitrogen and phosphate in the waters 10 to 100 meters around the sea area increased by 5% to 40%, and returned to the level before spraying within 6 to 24 hours.

Images