Device and method for monitoring diversity of ecological microorganisms in fresh water based on environmental DNA (Deoxyribose Nucleic Acid) technology

Abstract

The invention relates to a fresh water ecological microbial diversity monitoring device and method based on an environment DNA technology, and belongs to the technical field of water environment monitoring. The water delivery module is fixedly installed below the floating module, the sampling module is arranged on the outer side of the water delivery module and is in an annular shape, and the eD NA sampling assembly and the monitoring sensor assembly are located in the annular structure of the sampling module. The sampling module is used for unfolding the filter membrane during sampling and rolling up the filter membrane after sampling. According to the freshwater ecological microorganism diversity monitoring device and method based on the environmental DNA technology, the reel type filter membrane is adopted to filter a water body, and the filter membrane is unfolded and then wound underwater, so that enrichment of a larger amount of environmental DNA is facilitated, and the probability that a sample is polluted can be effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of water environment monitoring, and particularly relates to a device and method for monitoring the diversity of freshwater ecological microorganisms based on environmental DNA technology. Background Art

[0002] Microbial DNA in the freshwater environment will mix into the water in the form of secretions. Therefore, the microbial diversity in the water environment can be detected by collecting the environmental DNA of the water environment. The methods for monitoring biodiversity in the freshwater environment based on environmental DNA technology generally include steps such as DNA sample collection, DNA extraction, PCR amplification and sequencing, and bioinformatics analysis.

[0003] During the process of DNA sample collection, the precipitation method is generally used. The precipitation method is beneficial to obtaining a higher concentration of DNA, but a large amount of water samples need to be filtered. In this method, it is impossible to avoid external contamination or cross-contamination during the collection process. Moreover, in the application of environmental DNA technology, in order to ensure the purity and integrity of PCR amplification and sequencing, when collecting DNA substances, the influence of external environmental factors on the microorganisms and their DNA substances remaining in the water should be reduced to ensure the representativeness of the samples and the credibility of the monitoring results.

[0004] Therefore, the present invention proposes a device and method for monitoring the diversity of freshwater ecological microorganisms based on environmental DNA technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and method for monitoring the diversity of freshwater ecological microorganisms based on environmental DNA technology in order to solve the above problems.

[0006] The present invention realizes the above purpose through the following technical solutions:

[0007] The present invention provides a device for monitoring the diversity of freshwater ecological microorganisms based on environmental DNA technology, including a floating module for supporting the whole to float on the water surface, and further including a water delivery module fixedly installed below the floating module, a sampling module arranged outside the water delivery module and in a ring shape, and an eDNA sampling component and a monitoring sensor component located inside the ring structure of the sampling module;

[0008] The eDNA sampling component includes a scroll-type filter membrane located inside the ring structure of the sampling module. The sampling module is used to unfold the filter membrane during sampling and roll up the filter membrane after sampling. The water delivery module is used to guide the water flow through the unfolded filter membrane inside the sampling module during sampling so that eDNA adheres to the filter membrane;

[0009] The monitoring sensor component is used to obtain data on the water flow velocity, water temperature, dissolved oxygen, nitrogen, phosphorus, potassium, and heavy metals in the freshwater water area to be monitored.

[0010] As a further optimized solution of the present invention, the floating module includes a floating ring and a support frame arranged inside the floating ring.

[0011] As a further optimized solution of the present invention, the sampling module includes a top plate and a bottom plate, and filter meshes are provided on the inner and outer contours of the top plate and the bottom plate. The top plate, the bottom plate, and the filter meshes enclose a ring structure, and this ring structure is fixedly connected to the floating module. A rotating movable ring is embedded in the top plate, and a mounting seat for installing the eDNA sampling assembly is embedded in the movable ring. A clamping sleeve for fixing the free end of the filter membrane is provided on the bottom plate. The sampling module further includes a driving member for driving the rotation of the movable ring.

[0012] As a further optimized solution of the present invention, the driving member includes a driving rod, a turbine arranged inside the water delivery module is installed at the bottom end of the driving rod, and the movable ring is connected to the driving rod through a bracket.

[0013] As a further optimized solution of the present invention, the eDNA sampling assembly further includes a protective film in a cylindrical structure. A sealing plate is provided at the upper end of the protective film, a docking sleeve is provided at the lower end, a docking block is provided below the sealing plate, a movable rod is rotatably installed at the bottom of the docking block through a torsion spring, the filter membrane is wound around the outside of the movable rod, and a clamping member matching with the clamping sleeve is provided on the free end of the filter membrane. A sealing plug is provided on the docking sleeve.

[0014] As a further optimized solution of the present invention, the water delivery module includes a drainage member and the turbine is located inside the drainage member. The driving rod penetrates through the drainage member and is rotatably connected to the drainage member. The drainage member is communicated with the sampling module through a confluence mechanism. The bottom of the drainage member is connected to a drainage pipe through a water pump, and a filtering member is provided at the bottom of the drainage pipe.

[0015] As a further optimized solution of the present invention, the confluence mechanism includes a sealing cover located inside the sampling module, and the sealing cover is communicated with the inner drainage member through a plurality of branch pipes distributed in an annular array. A plurality of diversion blocks are provided inside the sealing cover and are evenly and staggeredly distributed.

[0016] As a further optimized solution of the present invention, the monitoring sensor assembly includes a housing arranged on the ring structure of the sampling module and a sensor group and a memory located inside the housing.

[0017] The present invention also provides a method for monitoring the diversity of freshwater ecological microorganisms based on environmental DNA technology, including the following steps:

[0018] S1. Install the eDNA sampling assembly on the sampling module and press the filter membrane into the sampling module; place the floating module on the water surface so that the whole formed by connecting the water delivery module, the sampling module, and the eDNA sampling assembly is immersed in water;

[0019] S2. Activate the water delivery module. The water flow passing through the water delivery module drives the sampling module to operate, causing the filter membrane to unfurl in a circular shape within the sampling module. After the filter membrane unfurls, the subsequent water flow passes through the filter membrane in sequence, enabling the eDNA in the water environment to be enriched on the filter membrane.

[0020] S3. After the sampling time ends, switch the water flow direction of the water delivery module to drive the sampling module to operate in the reverse direction, causing the filter membrane to wind back into a reel state. Lift the entire monitoring device out of the water body, then extract the filter membrane from the sampling module, disassemble the eDNA sampling component and place it in a freezing tool for storage. At the same time, export the data in the monitoring sensor component.

[0021] S4. Based on environmental DNA technology, sequentially perform separation, DNA extraction, and PCR amplification sequencing on the eDNA enriched on the filter membrane to obtain the microbial species information in the monitored freshwater water area. Combine the water flow velocity, water temperature, dissolved oxygen, nitrogen, phosphorus, potassium, and heavy metal data in the monitored freshwater water area exported from the monitoring sensor component to obtain the monitoring result of microbial diversity.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The present invention uses a reel-type filter membrane to filter water bodies. Compared with traditional circular filter membranes, it has a larger filtration area, which is conducive to enriching more eDNA.

[0024] 2. During the sampling process, through the cooperation of the driving member, movable ring, ferrule, and mounting seat, etc., the effect of automatically unfurling and then winding the filter membrane in the sampling module underwater by means of the driving force of the water flow is achieved. The operation is convenient and efficient, and the operator only needs to complete the installation work of the filter membrane. Before sampling, when the device is not in the water, the filter membrane is always in a wound state. After sampling, the filter membrane winds up first and then exits the water, that is, the filter membrane only unfurls when it is underwater. Compared with the traditional method of directly taking and placing the filter membrane by the operator under outdoor conditions, the above operation process can reduce the probability of sample contamination.

[0025] 3. The present invention uses the whole formed by connecting a turbine, a driving rod, and a bracket as the driving member, achieving the effect of driving the sampling module to operate by using the water flow passing through the water delivery component, that is, driving the whole formed by connecting the movable ring and the mounting seat to rotate, thereby driving the filter membrane to unfurl and wind up. Description of the Drawings

[0026] Figure 1 is the overall external view schematic diagram of the present invention;

[0027] Figure 2 is the top view schematic diagram of the floating module;

[0028] Figure 3 is the cooperation schematic diagram of the sampling module and the water delivery module;

[0029] Figure 4 It is a schematic diagram of the separation of the sampling module and the water delivery module;

[0030] Figure 5 It is a schematic diagram of the water delivery module;

[0031] Figure 6 It is a schematic diagram of the position distribution of the mounting base and the ferrule;

[0032] Figure 7 It is a sectional view of the cooperative installation of the sampling module and the eDNA sampling component;

[0033] Figure 8 It is a schematic diagram of the cooperation of the eDNA sampling component, the mounting base and the ferrule in the unfolded state of the filter membrane;

[0034] Figure 9 It is a schematic diagram of the unfolded state of the filter membrane;

[0035] Figure 10 It is a schematic diagram of the structural separation of the eDNA sampling component.

[0036] In the figure: 100, sampling module; 101, top plate; 102, bottom plate; 103, filter screen; 104, movable ring; 105, drive rod; 106, bracket; 107, ferrule; 108, mounting base; 200, floating module; 201, floating ring; 202, support frame; 300, water delivery module; 301, drain part; 302, sealing cover; 303, shunt block; 304, drain pipe; 305, filter part; 400, eDNA sampling component; 401, movable rod; 402, filter membrane; 403, clamping part; 404, protective film; 405, sealing plate; 406, docking sleeve; 407, docking block; 408, sealing plug. Detailed implementation manners

[0037] The following further describes the present application in detail. It is necessary to point out here that the following specific implementation manners are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above application content.

[0038] Embodiment 1

[0039] As Figure 1-10 shown, the freshwater ecological microbial diversity monitoring device based on the environmental DNA technology in this embodiment includes a floating module 200 for supporting the whole to float on the water surface, and also includes a water delivery module 300 fixedly installed below the floating module 200, a sampling module 100 arranged in a ring outside the water delivery module 300, and an eDNA sampling component 400 and a monitoring sensor component located inside the ring structure of the sampling module 100.

[0040] The eDNA sampling assembly 400 includes a self - rewinding scroll - type filter membrane 402. The eDNA sampling assembly 400 is installed on the sampling module 100, and the sampling module 100 is used to unfold the filter membrane 402 during sampling and roll up the filter membrane 402 after sampling. The water delivery module 300 is used to guide water flow through the unfolded filter membrane 402 within the sampling module 100 during sampling.

[0041] Microorganisms and their DNA substances in water bodies are difficult to collect because they are invisible to the naked eye. However, microorganisms have special structures on their surfaces, such as bacterial pili, capsules, and spores, etc., which can increase the contact area and adhesion force between bacteria and the surface of objects. At the same time, the surface of microbial cells usually carries a certain charge. In water bodies, this charged cell surface can attract particles or the surface of objects with opposite charges in the water through electrostatic attraction. Moreover, microorganisms can secrete extracellular polymers, which are sticky and can help microorganisms and their DNA substances firmly adhere to the surfaces of various objects in the water. Therefore, microorganisms and their DNA substances are easily attached to solid objects in water bodies. Therefore, the present invention uses the filter membrane 402 to capture microorganisms and their DNA substances in fresh - water bodies.

[0042] The sampling module 100 includes a top plate 101 and a bottom plate 102, and filter meshes 103 are provided on the inner and outer contours of both the top plate 101 and the bottom plate 102. The top plate 101, the bottom plate 102, and the filter meshes 103 enclose a ring - shaped structure, and this ring - shaped structure is fixedly connected to the floating module 200. A rotating movable ring 104 is embedded in the top plate 101, and a mounting seat 108 for installing the eDNA sampling assembly 400 is embedded in the movable ring 104. A retaining sleeve 107 for fixing the free end of the filter membrane 402 is provided on the bottom plate 102. The sampling module 100 further includes a driving member for driving the rotation of the movable ring 104. The driving member includes a driving rod 105. A turbine located within the water delivery module 300 is installed at the bottom end of the driving rod 105. The movable ring 104 is connected to the driving rod 105 through a bracket 106.

[0043] The water delivery module 300 includes a drainage member 301 and the turbine is located within the drainage member 301. The driving rod 105 penetrates through the drainage member 301 and is rotatably connected to the drainage member 301. The drainage member 301 is connected to the sampling module 100 through a confluence mechanism. The bottom of the drainage member 301 is connected to a drain pipe 304 through a water pump, and a filtering member 305 is provided at the bottom of the drain pipe 304.

[0044] The monitoring sensor assembly is used to obtain the water flow velocity, water temperature, dissolved oxygen, nitrogen, phosphorus, potassium, and heavy metal data of the fresh water area to be monitored, including a housing provided on the annular structure of the sampling module 100 and a sensor group (water flow velocity sensor, water temperature sensor, dissolved oxygen sensor, nitrogen, phosphorus, potassium sensor, heavy metal sensor) and a memory located inside the housing. The acquisition, storage, and export of data are all prior arts and will not be elaborated here.

[0045] The method for monitoring microbial diversity using the above-mentioned fresh water ecological microbial diversity monitoring device based on environmental DNA technology includes the following steps:

[0046] S1. Snap the eDNA sampling assembly 400 onto the mounting seat 108. Then adjust the angle of the filter membrane 402 so that its free end is aligned with the ferrule 107, and then press the filter membrane 402 into the sampling module 100, thereby completing the mating installation of the eDNA sampling assembly 400 and the sampling module 100; Place the floating module 200 on the water surface so that the whole formed by connecting the water delivery module 300, the sampling module 100, and the eDNA sampling assembly 400 is immersed in the water;

[0047] S2. Turn on the water pump in the water delivery module 300. Under the action of the water pump, the water in the monitored fresh water area passes through the sampling module 100, the confluence mechanism, and the drain 301 from the outside to the inside in sequence, and finally returns to the water environment through the drain pipe 304. When the water flow passes through the drain 301, it can drive the turbine therein to rotate, and then drive the whole formed by connecting the drive rod 105, the bracket 106, the movable ring 104, and the mounting seat 108 to rotate. On the eDNA sampling assembly 400, except that the free end of the filter membrane 402 is fixed by the ferrule 107, other parts are snap-connected to the mounting seat 108 as a whole. Therefore, except for the filter membrane 402, other parts of the eDNA sampling assembly 400 will rotate with the mounting seat 108, and the filter membrane 402 will gradually unwind during this process. Finally, the filter membrane 402 will unfold into an approximately annular structure. After the filter membrane 402 unfolds, the subsequent water flow passing through the sampling module 100 will evenly pass through the filter membrane 402, and the eDNA in the water flow will be enriched on the filter membrane 402.

[0048] It should be noted that when the filter membrane 402 is completely unfolded, the free end of the filter membrane 402 that rotates nearly one circumference will contact the ferrule 107. At this time, the ferrule 107 can play a limiting role, that is, it prevents the whole formed by connecting the movable ring 104, the mounting seat 108, and the free end of the filter membrane 402 from continuing to rotate, so that the filter membrane can be kept in a completely unfolded state. In this state, the water flow can still freely pass through the turbine, but it will no longer drive the turbine to rotate.

[0049] S3. After the sampling time ends, adjust the water pump in the water delivery module 300 to make it deliver water in the reverse direction. The water flow can drive the turbine to rotate in the reverse direction, thereby driving the overall rotation of the drive rod 105, the bracket 106, the movable ring 104, and the mounting seat 108 connected together back to the initial position. During this process, the filter membrane 402 will gradually wind back to the initial state by itself. Lift the entire monitoring device out of the water body, then extract the filter membrane 402 in the sampling module 100, disassemble the eDNA sampling assembly 400 and place it in a freezing tool for storage, and at the same time export the data in the monitoring sensor assembly;

[0050] S4. Based on the environmental DNA technology, perform separation, DNA extraction, and PCR amplification sequencing on the eDNA enriched on the filter membrane 402 in sequence to obtain the microbial species information in the monitored freshwater water area. Combine the water flow velocity, water temperature, dissolved oxygen, nitrogen, phosphorus, potassium, and heavy metal data in the monitored freshwater water area exported from the monitoring sensor assembly to obtain the monitoring result of microbial diversity, that is, the relationship between the microbial species and numbers and the water flow velocity, water temperature, dissolved oxygen, nitrogen, phosphorus, potassium, and heavy metals in the freshwater water body (it can be analyzed whether they are linearly correlated through a scatter plot).

[0051] Preferably, the floating module 200 includes a floating ring 201 and a support frame 202 provided inside the floating ring 201. During use, the monitoring device can be directly placed in the freshwater water area to be monitored. The entire device can float on the water surface by means of the floating ring 201. In the floating state, the eDNA sampling assembly 400 is just below the water surface. During actual use, a photovoltaic module is also provided on the support frame 202 of the floating module 200, and the photovoltaic power generation supplies power to the electrical components on the device. This technology is a conventional technology and does not fall within the scope of protection required by the present invention.

[0052] Preferably, the eDNA sampling assembly 400 further includes a protective film 404 in a cylindrical structure. The upper end of the protective film 404 is provided with a sealing plate 405, the lower end is provided with a docking sleeve 406, a docking block 407 is provided below the sealing plate 405, a movable rod 401 is rotatably installed at the bottom of the docking block 407 through a torsion spring, the filter membrane 402 is wound around the outside of the movable rod 401, and a clamping member 403 matching with the clamping sleeve 107 is provided at the free end of the filter membrane 402. A sealing plug 408 is provided on the docking sleeve 406;

[0053] When installing the eDNA sampling component 400, first remove the sealing plug 408 and store it aseptically. Then immediately sleeve the docking sleeve 406 onto the mounting base 108. Next, rotate and adjust the angle of the filter membrane 402 so that the clamping member 403 aligns with the clamping sleeve 107. Then place the lower part of the filter membrane 402 into the sampling module 100 and press the docking block 407 into the mounting base 108. The clamping member 403 will automatically engage with the clamping sleeve 107 to fix the free end of the filter membrane 402. During this process, the protective film 404 will be folded and stacked between the sealing plate 405 and the docking sleeve 406.

[0054] Since the movable rod 401 is rotationally connected to the docking block 407 through a torsion spring, when the movable rod 401 rotates synchronously with the mounting base 108, the movable rod 401 will also continuously rotate self - driven under the action of the pulling force, so that the filter membrane 402 is unrolled until the movable rod 401 rotates to a position where it fits with the clamping sleeve 107. When the movable rod 401 rotates in the opposite direction with the mounting base 108, the movable rod 401 will continuously rotate in the opposite direction under the action of the torsion spring, achieving the effect of re - winding the filter membrane 402. After sampling, lifting the sealing plate 405 can lift the filter membrane 402, and the protective film 404 will automatically unfold and cover the outside of the filter membrane 402. Finally, remove the docking sleeve 406 and immediately plug back the sealing plug 408. During the operation process, the operator needs to wear sterile gloves.

[0055] To reduce the difficulty of positioning and installing the filter membrane 402, the size of the docking block 407 can be appropriately increased, preferably adopting an arc structure that fits the rolled - up filter membrane 402. Correspondingly, the inner contour of the mounting base 108 and the outer contour of the sealing plate 405 can both be processed into structures corresponding to the overall contour formed by the connection of the filter membrane 402 and the docking block 407.

[0056] Preferably, the confluence mechanism includes a sealing cover 302 located inside the sampling module 100, and the sealing cover 302 is communicated with the inner drainage member 301 through a number of branch pipes distributed in an annular array. A number of flow - dividing blocks 303 are arranged in the sealing cover 302 in a uniformly staggered manner. Under the action of the confluence mechanism, the water flow in all directions can evenly pass through the sampling module 100 and the filter membrane 402 inside it, which is beneficial to increasing the environmental DNA enriched on the filter membrane 402.

[0057] The above - described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A freshwater ecological microbial diversity monitoring device based on environmental DNA technology, comprising a floating module (200) for supporting the whole to float on the water surface, characterized in that, It also includes a water conveyance module (300) fixedly installed below the floating module (200), a sampling module (100) arranged outside the water conveyance module (300) and in a ring shape, and an eDNA sampling component (400) and a monitoring sensor component located inside the ring structure of the sampling module (100); The eDNA sampling component (400) includes a scroll-type filter membrane (402) located inside the ring structure of the sampling module (100). The sampling module (100) is used to unfold the filter membrane (402) during sampling and roll up the filter membrane (402) after sampling. The water conveyance module (300) is used to guide water flow through the unfolded filter membrane (402) inside the sampling module (100) during sampling so that eDNA adheres to the filter membrane (402); The monitoring sensor component is used to obtain data on water flow velocity, water temperature, dissolved oxygen, nitrogen, phosphorus, potassium, and heavy metals in the freshwater area to be monitored.

2. The freshwater ecological microbial diversity monitoring device based on the environmental DNA technology according to claim 1, wherein The floating module (200) includes a floating ring (201) and a support frame (202) arranged inside the floating ring (201).

3. The freshwater ecological microbial diversity monitoring device based on the environmental DNA technology according to claim 1, characterized in that, The sampling module (100) includes a top plate (101) and a bottom plate (102), and filter meshes (103) are provided on the inner and outer contours of the top plate (101) and the bottom plate (102). The top plate (101), the bottom plate (102), and the filter meshes (103) enclose to form the ring structure, and this ring structure is fixedly connected to the floating module (200). A rotating movable ring (104) is embedded in the top plate (101), and a mounting seat (108) for installing the eDNA sampling component (400) is embedded in the movable ring (104). A clamping sleeve (107) for fixing the free end of the filter membrane (402) is provided on the bottom plate (102). The sampling module (100) further includes a driving member for driving the rotation of the movable ring (104).

4. The freshwater ecological microbial diversity monitoring device based on the environmental DNA technology according to claim 3, wherein, The driving member includes a driving rod (105). A turbine arranged inside the water conveyance module (300) is installed at the bottom end of the driving rod (105). The movable ring (104) is connected to the driving rod (105) through a bracket (106).

5. The freshwater ecological microbial diversity monitoring device based on the environmental DNA technology according to claim 1, wherein The eDNA sampling component (400) further includes a protective film (404) in a cylindrical structure. A sealing plate (405) is provided at the upper end of the protective film (404), and a docking sleeve (406) is provided at the lower end. A docking block (407) is provided below the sealing plate (405). A movable rod (401) is rotatably installed at the bottom of the docking block (407) through a torsion spring. The filter membrane (402) is wound around the outside of the movable rod (401), and a clamping member (403) matching with the clamping sleeve (107) is provided at the free end of the filter membrane (402). A sealing plug (408) is provided on the docking sleeve (406).

6. The freshwater ecological microbial diversity monitoring device based on the environmental DNA technology according to claim 4, characterized in that, The water delivery module (300) includes a drain member (301) and a turbine is located within the drain member (301). A drive rod (105) penetrates through the drain member (301) and is rotatably connected to the drain member (301). The drain member (301) is communicated with the sampling module (100) through a confluence mechanism. The bottom of the drain member (301) is connected to a drain pipe (304) through a water pump, and a filter member (305) is provided at the bottom of the drain pipe (304).

7. The freshwater ecological microbial diversity monitoring device based on the environmental DNA technology according to claim 6, characterized in that, The confluence mechanism includes a sealing cover (302) located inside the sampling module (100), and the sealing cover (302) is communicated with the inner drain member (301) through a plurality of branch pipes distributed in an annular array. A plurality of flow splitting blocks (303) are provided inside the sealing cover (302) and are evenly and staggeredly distributed.

8. The freshwater ecological microbial diversity monitoring device based on the environmental DNA technology according to claim 1, wherein The monitoring sensor assembly includes a housing provided on the annular structure of the sampling module (100), and a sensor group and a memory located inside the housing.

9. A method for monitoring the diversity of freshwater ecological microorganisms, based on the monitoring device according to any one of claims 1-8, characterized in that, It includes the following steps: S1. Install the eDNA sampling assembly (400) on the sampling module (100), and press the filter membrane (402) into the sampling module (100); place the floating module (200) on the water surface so that the whole formed by connecting the water delivery module (300), the sampling module (100), and the eDNA sampling assembly (400) is immersed in the water. S2. Turn on the water delivery module (300), and the water flow passing through the water delivery module (300) drives the sampling module (100) to operate, so that the filter membrane (402) unfolds annularly inside the sampling module (100). After the filter membrane (402) unfolds, the subsequent water flow sequentially passes through the filter membrane (402), so that the eDNA in the water environment is enriched on the filter membrane (402). S3. After the sampling time ends, switch the water flow delivery direction of the water delivery module (300) to drive the sampling module (100) to run in the reverse direction, so that the filter membrane (402) is rewound into a reel state; lift the whole monitoring device out of the water body, then extract the filter membrane (402) inside the sampling module (100), disassemble the eDNA sampling assembly (400) and place it in a freezing tool for storage, and at the same time export the data in the monitoring sensor assembly. S4. Based on the environmental DNA technology, perform separation, DNA extraction, and PCR amplification sequencing processing on the eDNA enriched on the filter membrane (402) in sequence to obtain the microbial species information in the monitored freshwater water area. Integrate the water flow velocity, water temperature, dissolved oxygen, nitrogen, phosphorus, potassium, and heavy metal data in the monitored freshwater water area exported from the monitoring sensor assembly to obtain the monitoring result of microbial diversity.

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