Method for controlling algae by using young silver carps and bighead carps

Abstract

The invention provides a method for controlling algae by using young silver carps and bighead carps, and relates to the technical field of ecological restoration of water bodies. The method provided by the invention comprises the following step: the weights of fry of the young silver carp and the bighead carp are both 5-9g. According to the method, the young silver carps and the bighead carps are adopted for controlling algae, the growth speed of the young silver carps and the bighead carps is high, the fry source is wide, the cost is relatively low, and a large amount of food is needed in the growth process to meet the energy requirement. The algae control capability of the young silver carps and bighead carps is evaluated through a system, it is determined that the content of chlorophyll a in water can be remarkably reduced through the method, and the control effect of the young silver carps and bighead carps on cyanobacterial bloom is clear.

Description

Technical Field

[0001] This invention belongs to the field of aquatic ecological restoration technology, specifically relating to a method for controlling algae using juvenile silver carp and bighead carp. Background Technology

[0002] The outbreak of cyanobacterial blooms not only disrupts the original ecological balance of shallow lakes, inhibits the growth of aquatic vegetation, and reduces biodiversity, but also pollutes drinking water sources due to the production of toxic substances such as microcystin, directly threatening human health. At the same time, it damages the landscape function of water bodies and restricts the sustainable development of regional ecological environment and socio-economic development. Therefore, the effective management of cyanobacterial blooms in shallow lakes has become a key issue that urgently needs to be addressed in the field of ecological and environmental protection.

[0003] The main methods for controlling cyanobacterial blooms in shallow lakes fall into three categories: chemical, physical, and biological methods. Chemical methods involve adding algicides and flocculants to the water to control algae. While this method can quickly kill or remove algae in the short term, it has serious side effects: chemical agents tend to remain in the water, polluting the aquatic environment, toxicizing non-target aquatic organisms such as fish and zooplankton, and even accumulating through the food chain, affecting human health. Furthermore, it easily leads to drug resistance in cyanobacteria, making long-term stable algae control difficult. Physical methods mainly include algae harvesting, aeration, and bottom sediment dredging. These methods are cumbersome and costly, and can only remove existing algae or surface pollutants, failing to fundamentally solve the problem of eutrophication-induced algae growth. They are merely treating the symptoms, not the root cause, and the control effect is unsustainable.

[0004] Biological methods have become the mainstream research direction for the treatment of cyanobacterial blooms in shallow lakes due to their advantages such as environmental friendliness, no secondary pollution, and strong sustainability. Developing an ecological algae control method for shallow lakes with juvenile silver carp and bighead carp as the core, clarifying its suitable treatment conditions and technical parameters, and reducing treatment costs are of great practical significance for improving the treatment level of cyanobacterial blooms in shallow lakes and ensuring ecological security and human health. Summary of the Invention

[0005] The purpose of this invention is to provide an ecological algae control method using juvenile silver carp and bighead carp as the core, thereby reducing chlorophyll in the water. a content.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for controlling algae in juvenile silver carp and bighead carp, comprising the following steps: the juvenile silver carp and bighead carp fry have a weight of 5-9 g each.

[0007] Preferably, the ratio of silver carp to bighead carp is set to 2-3:1.

[0008] Preferably, the stocking density of silver carp and bighead carp is 90~110 g / m³. 3 .

[0009] Preferably, the algae include one or more of the following phyla: Euglenophyta, Dinophyta, Cryptophyta, Diatoms, Chlorophyta, and Cyanobacteria.

[0010] Preferably, the apparatus used in the method includes a medium universe simulation test device, which includes a 300-400 L large barrel, 5-7 kg of Dianchi Lake bottom mud, and a shade net.

[0011] Preferably, the medium universe simulation experimental device also includes a fishing net, and the 5-7 kg of Dianchi Lake bottom mud is passed through a sieve with a diameter of 500 µm to 2 mm.

[0012] The present invention also provides the method for reducing chlorophyll in water bodies. a Application of content.

[0013] Preferably, after implementing the method for 12-18 days, the chlorophyll in the water body... a The content decreased.

[0014] Preferably, the water body includes a shallow lake.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for controlling algae blooms using juvenile silver carp and bighead carp fry, both weighing 5-9 g. Juvenile silver carp and bighead carp grow rapidly, are widely available, and are relatively inexpensive. They require a large amount of food to meet their energy needs during their growth. Through systematic evaluation of the algae control ability of juvenile silver carp and bighead carp, this invention demonstrates that the method can significantly reduce chlorophyll a content in water bodies, clarifying the effectiveness of using juvenile silver carp and bighead carp in controlling cyanobacterial blooms. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the space experiment device in Example 1.

[0017] Figure 2 To treat chlorophyll in water bodies treated with different stocking densities of silver carp and bighead carp in Example 1 a The results show the changes, where uppercase letters indicate differences between different treatment groups at the same time, lowercase letters indicate differences between groups at different time points within each treatment, and different letters indicate significant differences. P <0.05).

[0018] Figure 3The results show the changes in nitrogen content in the water body treated with different stocking densities of silver carp in Example 1; where A represents the change in total nitrogen in the water body treated with different stocking densities of silver carp, B represents the change in total phosphorus in the water body treated with different stocking densities of silver carp, and C represents the change in ammonia nitrogen in the water body treated with different stocking densities of silver carp; uppercase letters indicate differences between different treatment groups at the same time, lowercase letters indicate differences between groups at different time points within each treatment, and different letters indicate significant differences (…). P <0.05).

[0019] Figure 4 The results show the changes in phosphorus content in water bodies treated with different stocking densities of bighead carp in Example 1; where A represents the change in total nitrogen in water bodies treated with different stocking densities of bighead carp, B represents the change in total phosphorus in water bodies treated with different stocking densities of bighead carp, and C represents the change in ammonia nitrogen in water bodies treated with different stocking densities of bighead carp; uppercase letters indicate differences between different treatment groups at the same time, lowercase letters indicate differences between groups at different time points within each treatment, and different letters indicate significant differences (…). P <0.05).

[0020] Figure 5 The results show the changes in phosphorus content in the water treated with different stocking densities of silver carp and bighead carp in Example 1; where A represents the results of the silver carp treatment with different stocking densities, and B represents the results of the bighead carp treatment with different stocking densities; uppercase letters indicate differences between different treatment groups at the same time, lowercase letters indicate differences between groups at different time points within each treatment, and different letters indicate significant differences. P <0.05).

[0021] Figure 6 To illustrate the effect of stocking different proportions of silver carp and bighead carp on chlorophyll in Example 2. a Where 1:0, 1:1, 2:1, and 3:1 represent the ratio of silver carp to bighead carp; uppercase letters indicate differences between different treatment groups at the same time point, lowercase letters indicate differences between groups at different time points within each treatment, and different letters indicate significant differences. P <0.05).

[0022] Figure 7 The results of total nitrogen changes after stocking different ratios of silver carp and bighead carp in Example 2 are shown. In this example, 1:0, 1:1, 2:1, and 3:1 represent the ratio of silver carp to bighead carp. Uppercase letters indicate differences between different treatment groups at the same time point, lowercase letters indicate differences between groups at different time points within each treatment, and different letters indicate significant differences. P <0.05).

[0023] Figure 8The results of total phosphorus changes after stocking different ratios of silver carp and bighead carp in Example 2 are shown. In this example, 1:0, 1:1, 2:1, and 3:1 represent the ratio of silver carp to bighead carp. Uppercase letters indicate differences between different treatment groups at the same time point, lowercase letters indicate differences between groups at different time points within each treatment, and different letters indicate significant differences. P <0.05).

[0024] Figure 9 The biomass of phytoplankton after stocking different ratios of silver carp and bighead carp in Example 2 is given. Among them, 1:0, 1:1, 2:1 and 3:1 are the ratios of silver carp to bighead carp.

[0025] Figure 10 The effect of different sizes of silver carp and bighead carp on chlorophyll in Example 3 a The removal effect; lowercase letters indicate differences between treatment groups, and different letters indicate significant differences ( P <0.05).

[0026] Figure 11 The results of Example 3 show the effects of different sizes of silver carp and bighead carp on total nitrogen and total phosphorus. Specifically, A represents the effect of different sizes of silver carp and bighead carp on total nitrogen, B represents the effect of different sizes of silver carp and bighead carp on total phosphorus, and C represents the effect of different sizes of silver carp and bighead carp on ammonia nitrogen.

[0027] Figure 12 The results show the changes in the biomass and proportion of each phytoplankton phylum after water treatment with silver carp and bighead carp of different sizes in Example 3. In this example, a represents the biomass of each phytoplankton phylum, and b represents the proportion of each phytoplankton phylum. L-large represents silver carp with a size of 26-28 g, L-small represents silver carp with a size of 5-7 g, Y-large represents bighead carp with a size of 26-28 g, Y-small represents bighead carp with a size of 5-7 g, and CK represents the control group without fish. Detailed Implementation

[0028] This invention provides a method for controlling algae growth using juvenile silver carp and bighead carp, comprising the following steps: the weight of the juvenile silver carp and bighead carp fry is preferably 5-9 g, more preferably 6-8 g. As an optional embodiment, the weight of the bighead carp fry is 6-8 g, and the body length is 7-9 cm. The ratio of silver carp to bighead carp is preferably 2-3:1, more preferably 2:1. The stocking density of the silver carp and bighead carp is preferably 90-110 g / m³. 3 More preferably 95~105 g / m 3 More preferably 100 g / m 3 The algae mentioned are one or more of the following phyla: Euglenophyta, Dinophyta, Cryptophyta, Diatoms, Chlorophyta, and Cyanobacteria.

[0029] In this invention, the method utilizes a cosmic simulation experimental apparatus, which includes a 300-400 L large barrel, 5-7 kg of Dianchi Lake sediment, a shade net, and a fishing net. Each 300-400 L barrel contains 5-7 kg of Dianchi Lake sediment. The barrel wall is covered with a shade net to prevent direct sunlight from promoting biofilm growth. The fishing net covers the barrel to prevent fish from jumping out of the water during the experiment. The 5-7 kg of Dianchi Lake sediment is passed through a 500 µm-2 mm sieve. The water used in the cosmic simulation experiment is taken from the outer sea of ​​Dianchi Lake. Algae are added to the cosmic simulation experimental apparatus, with an initial concentration of 40-200 µg / L. The algae are one or more of the following phyla: Euglena, Dinophyta, Cryptophyta, Diatoms, Chlorophyta, and Cyanobacteria. As an optional implementation, the initial concentration in the experimental barrel is measured to be 192.03 µg / L after the concentrated algae slurry is added.

[0030] The present invention also provides the method for reducing chlorophyll in water bodies. a The application in the content is specifically that after implementing the method for 12-18 days, the chlorophyll content in the water body... a The content is reduced. The water body is a shallow lake. As an optional implementation, the shallow lake is the outer sea of ​​Dianchi Lake in Kunming City, Yunnan Province.

[0031] This invention systematically evaluates the regulatory effects of juvenile silver carp and bighead carp on cyanobacterial blooms through a mid-cosmic simulation experiment, focusing on fish-algae interactions, density thresholds, polyculture ratios, and size selection. It provides a method for controlling algae blooms using juvenile silver carp and bighead carp. Juvenile silver carp and bighead carp have rapid growth rates, are widely available as seedlings, and are relatively inexpensive. However, they require a large amount of food to meet their energy needs during their growth. Through systematic evaluation of the algae control ability of juvenile silver carp and bighead carp, this invention confirms that the method can significantly reduce chlorophyll in the water using juvenile silver carp and bighead carp. a content.

[0032] In this invention, the bottom sediment, experimental water, and concentrated algae slurry all come from the outer sea of ​​Dianchi Lake in Kunming City, Yunnan Province.

[0033] To further illustrate the present invention, the invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the invention.

[0034] Unless otherwise specified, the experimental methods used in the following examples are conventional preparation methods; the materials and equipment used are commercially available unless otherwise specified.

[0035] Example 1 A total of 21 experimental barrels were set up. The experimental setup (barrels) consisted of 300 L barrels (top diameter 92 cm, bottom diameter 74 cm, height 75 cm). The water used in the cosmic simulation experiment was taken from the outer sea of ​​Dianchi Lake. 6 kg of Dianchi Lake bottom mud (screened through a 2 mm sieve to remove impurities) was added to each barrel. The barrel walls were covered with a shade net to prevent direct sunlight from promoting biofilm growth. A fishing net was placed on top of the barrels to prevent fish from jumping out of the water during the experiment. A schematic diagram of the cosmic simulation experimental setup is shown below. Figure 1 .

[0036] Before starting the experiment, add concentrated algae slurry collected using a phytoplankton net to each experimental tank. During the experiment, first fill a 300L tank with the water taken from the outer sea of ​​Dianchi Lake, then add the concentrated algae slurry and mix thoroughly before starting. After adding the concentrated algae slurry, ensure that the initial concentration in the experimental tank is 134.24 µg / L.

[0037] A concentrated algal slurry was obtained from the surface of Dianchi Lake in Kunming, Yunnan Province, using a phytoplankton net. The specific method for obtaining the concentrated algal slurry was as follows: A No. 25 phytoplankton net was slowly dragged in an "∞" shape at a speed of 20 cm / s to 30 cm / s from the surface of the water to a depth of 0.5 m for about 1 min to 3 min. The phytoplankton net was then lifted to the surface, and the sample was collected in a container at the bottom of the net, thus obtaining the concentrated algal slurry.

[0038] The fish fry used in the experiment were purchased from a fish fry shop in Yongchuan, Chongqing. The fry were 7-9 cm in length and 6-8 g in weight. Upon delivery, the fry were acclimatized for one week. The fry with better survival rates were selected and placed into the experimental apparatus to begin the experiment. During the experiment, any silver carp or bighead carp that died were promptly replaced. The experimental period was 12 days, with samples taken every 3 days.

[0039] The experiment was conducted at three densities to investigate the control effects of silver carp and bighead carp on cyanobacterial blooms under different density conditions. The fish biomass was 50 g / m³. 3 (Low-density group), 100 g / m³ 3 (Medium density group), 150 g / m³ 3 (High-density group) Three densities.

[0040] After stocking silver carp and bighead carp, nitrogen, phosphorus, and various algae (biomass) content were tested according to the "Fisheries Ecological Environment Monitoring Standard Part III Freshwater" (SC / T9102.3-2007). Chlorophyll a Measurements were performed using the spectrophotometric method for the determination of chlorophyll in water (SL 88-2012:11-2012).

[0041] Phytoplankton species composition, density and biomass were identified and analyzed using microscopy, specifically following the methods described in "Methods for Research on Freshwater Plankton" (edited by Zhang Zongshe and Huang Xiangfei, Science Press, 1991) and "Freshwater Algae of China" (edited by Hu Hongjun and Wei Yinxin, Science Press, 2006).

[0042] Result: Passed Figure 2 , Figure 3 , Figure 4 and Figure 5 Comparison 50 g / m 3 100 g / m 3 150 g / m 3 The control effects of silver carp and bighead carp at three different densities on cyanobacterial blooms showed that different densities of silver carp and bighead carp all had a certain effect on cyanobacterial blooms. The algae control effect of silver carp was significantly stronger than that of bighead carp. The removal effect of chlorophyll a after stocking silver carp was greater than that of the treatment group stocked with bighead carp.

[0043] Example 2 The experiment was conducted using the same apparatus as in Example 1. Water was drawn from Dianchi Lake, and concentrated algae slurry collected using a phytoplankton net was added to each experimental tank before the experiment began. During the experiment, the water taken from the outer sea of ​​Dianchi Lake was first poured into a 300L tank until it was full, then the concentrated algae slurry was added and mixed thoroughly before starting. After adding the concentrated algae slurry, the initial concentration in the experimental tank was ensured to be 192.03 µg / L.

[0044] A concentrated algal slurry was obtained from the surface of Dianchi Lake in Kunming, Yunnan Province, using a phytoplankton net. The specific method for obtaining the concentrated algal slurry was as follows: A No. 25 phytoplankton net was slowly dragged in an "∞" shape at a speed of 20 cm / s to 30 cm / s from the surface of the water to a depth of 0.5 m for about 1 min to 3 min. The phytoplankton net was then lifted to the surface, and the sample was collected in a container at the bottom of the net, thus obtaining the concentrated algal slurry.

[0045] Based on the results in Example 1, the fish biomass was 100 g / m³. 3 Time-controlled algae cultivation yielded the best results; therefore, the stocking density of fish in this experiment was set at 100 g / m³. 3 .

[0046] The fish fry used in the experiment were purchased from a fish fry shop in Yongchuan, Chongqing. The fry were 7-9 cm long and weighed 6-8 g. When the fry arrived, they were acclimatized for a week. The fry with better survival were selected to start the experiment. If any silver carp or bighead carp died during the experiment, they were replaced in time.

[0047] The ratio of silver carp to bighead carp was set as G0 (1:0), G1 (1:1), G2 (2:1), and G3 (3:1). The experiment started on July 25, 2024, with samples taken every 3 days, and ended on August 10, 2024, with an experimental period of 16 days.

[0048] After stocking silver carp and bighead carp, nitrogen, phosphorus, and various algae (biomass) content were tested according to the "Fisheries Ecological Environment Monitoring Standard Part III Freshwater" (SC / T9102.3-2007). Chlorophyll a Measurements were performed using the spectrophotometric method for the determination of chlorophyll in water (SL 88-2012:11-2012).

[0049] Phytoplankton species composition, density and biomass were identified and analyzed using microscopy, specifically following the methods described in "Methods for Research on Freshwater Plankton" (edited by Zhang Zongshe and Huang Xiangfei, Science Press, 1991) and "Freshwater Algae of China" (edited by Hu Hongjun and Wei Yinxin, Science Press, 2006).

[0050] Results: The effects of different ratios of silver carp and bighead carp on controlling cyanobacterial blooms were investigated. Figure 6 , Figure 7 , Figure 8 and Figure 9 The experimental results show that a silver carp to bighead carp ratio of 2:1 has an effect on chlorophyll production. a The removal effect was the best, and the volume concentration of algae also showed a significant downward trend. The second best was silver carp and bighead carp, with a ratio of 3:1.

[0051] Example 3 The experiment was conducted in the same apparatus as in Example 1. Water was drawn from the outer sea of ​​Dianchi Lake and filtered out large particulate impurities using a 500 µm sieve. The water was left to stand for two days after being drawn before the experiment officially began.

[0052] During the experiment, water collected from the outer reaches of Dianchi Lake was first poured into a 300L tank until full, then concentrated algae slurry was added and mixed thoroughly before starting. Before the experiment began, concentrated algae slurry collected using a phytoplankton net was added to each experimental tank. After adding the concentrated algae slurry, the initial concentration in the silver carp experimental tank was ensured to be 51.9 µg / L; the initial concentration in the bighead carp experimental tank was ensured to be 46.6 µg / L (since the removal rate was the primary focus, the initial concentration was not specifically required).

[0053] A concentrated algal slurry was obtained from the surface of Dianchi Lake in Kunming, Yunnan Province, using a phytoplankton net. The specific method for obtaining the concentrated algal slurry was as follows: A No. 25 phytoplankton net was slowly dragged in an "∞" shape at a speed of 20 cm / s to 30 cm / s from the surface of the water to a depth of 0.5 m for about 1 min to 3 min. The phytoplankton net was then lifted to the surface, and the sample was collected in a container at the bottom of the net, thus obtaining the concentrated algal slurry.

[0054] The overall stocking density for the experiment was still set at 100 g / m³. 3 Five fry were placed in each bucket for smaller silver carp (5-7 g) and bighead carp, while one fry was placed in each bucket for larger fry (26-28 g). The experiment lasted 19 days, with samples taken every three days.

[0055] After silver carp and bighead carp were stocked separately, nitrogen, phosphorus, and various algae (biomass) content were tested according to the "Fisheries Ecological Environment Monitoring Standard Part III Freshwater" (SC / T9102.3-2007). Chlorophyll a Measurements were performed using the spectrophotometric method for the determination of chlorophyll in water (SL 88-2012:11-2012).

[0056] Phytoplankton species composition, density and biomass were identified and analyzed using microscopy, specifically following the methods described in "Methods for Research on Freshwater Plankton" (edited by Zhang Zongshe and Huang Xiangfei, Science Press, 1991) and "Freshwater Algae of China" (edited by Hu Hongjun and Wei Yinxin, Science Press, 2006).

[0057] Result: From Figure 10 , Figure 11 and Figure 12 It can be seen that for silver carp and bighead carp weighing 5-7 g and 26-28 g respectively, the silver carp weighing 26-28 g had the best effect on controlling cyanobacterial blooms and on chlorophyll production. a The removal rate of chlorophyll was 65.6%, followed by silver carp (5-7 g) with a removal rate of 44%. Both sizes of silver carp showed similar chlorophyll removal rates. a There was no significant difference in removal efficiency between the two methods. However, young silver carp and bighead carp grow rapidly, have a wide range of seedling sources, and are relatively inexpensive. They require a large amount of food to meet their energy needs during their growth.

[0058] In summary, through systematic evaluation of the algae control ability of juvenile silver carp and bighead carp, it was determined that the method of the present invention can significantly reduce chlorophyll in water bodies using juvenile silver carp and bighead carp. a content.

[0059] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for controlling algae growth using juvenile silver carp and bighead carp, characterized in that, The process includes the following steps: the weight of the young silver carp and bighead carp fry is 5-9 g.

2. The method according to claim 1, characterized in that, The ratio of silver carp to bighead carp should be set at 2-3:

1.

3. The method according to claim 1, characterized in that, The stocking density for silver carp and bighead carp is 90-110 g / m³. 3 .

4. The method according to claim 1, characterized in that, The algae include one or more of the following phyla: Euglenophyta, Dinophyta, Cryptophyta, Diatoms, Chlorophyta, and Cyanobacteria.

5. The method according to claim 1, characterized in that, The method employs a device including a medium universe simulation test apparatus, which includes a 300-400 L large barrel, 5-7 kg of Dianchi Lake bottom mud, and a shade net.

6. The method according to claim 5, characterized in that, The aforementioned cosmic simulation experimental device also includes a fishing net, through which 5-7 kg of Dianchi Lake bottom mud is passed through a 500 µm-2 mm sieve.

7. The method according to any one of claims 1 to 6 for reducing chlorophyll in water bodies a Application of content.

8. The application according to claim 7, characterized in that, After implementing the method described in claims 1-6 for 12-18 days, the chlorophyll in the water body a The content decreased.

9. The application according to claim 7, characterized in that, The water bodies include shallow lakes.

Images