In-situ observation device and method for degradation of aquatic plants in cold and arid region lakes

Abstract

The present application relates to a kind of cold arid region lake aquatic plant in situ degradation observation device and method, belong to environmental protection technical field, including support base and install on the support base and distribution area at least include above water surface, below water surface fixed distance and underwater three regions three groups of plant degradation observation box, each group of the plant degradation observation box can be detachably provided with multiple degradation observation units, the degradation observation unit stores corresponding aquatic plant of lake, and observation is carried out using observation device, can be adjusted observation box and internal observation group layout according to different ice seal period, different temperature, different water level, solve the in situ degradation process observation problem of aquatic plant in different situations of cold arid region lake, for the degradation process and mechanism research of a large number of aquatic plant litter of cold arid region lake, and endogenous pollution load evaluation has important significance.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, specifically to an in-situ degradation monitoring device and method for aquatic plants in lakes in cold and arid regions. Background Technology

[0002] The typical characteristics of eutrophication in lakes typically include the accumulation of nutrients such as nitrogen and phosphorus in the water and sediment, large-scale algal blooms, and the mass mortality and degradation of aquatic plants. Among these, the succession of aquatic plant communities is fundamental to the health of lake ecosystems. Numerous studies both domestically and internationally have shown that the continuous degradation of submerged vegetation during eutrophication has been a prominent problem for eutrophic lakes. However, in cold and arid regions, due to factors such as water scarcity, high evaporation rates, salinization, and rising temperatures, the structure of lake ecosystems in these areas tends to be homogeneous, with simple aquatic plant communities and low resistance to disturbance. Many lakes continue to face the problem of excessive proliferation of a few or single aquatic plant species, impacting the overall health of the lake's aquatic ecosystem.

[0003] The continuous expansion of a few or single species under conditions of rising temperatures and low water levels has led to a dramatic increase in biomass, significantly reducing water connectivity and flow. Furthermore, the failure to effectively manage the large quantities of decaying plant remains has resulted in the accumulation and degradation of plant debris, continuously worsening lake water quality and exacerbating endogenous pollution loads. The degradation of large quantities of aquatic plant remains releases large amounts of nutrients such as nitrogen and phosphorus, exacerbating eutrophication, and also consumes significant amounts of oxygen in the water, causing extreme hypoxia events. Therefore, the scientific management of large quantities of aquatic plants has become one of the core issues in the water environment management of lakes in many cold and arid regions. Research on the decay and degradation processes of large quantities of aquatic plants in lakes can provide scientific theoretical support for the scientific management of aquatic plants. Especially in recent years, the continuous and excessive expansion of a few aquatic plant species in lakes in cold and arid regions due to intensifying global warming makes in-situ research on the degradation processes of these plants of great significance. However, current research on aquatic plant degradation processes is mostly conducted in indoor simulated environments, lacking systematic studies on in-situ degradation processes in the field. The main reasons for this are twofold: firstly, there is a lack of in-situ degradation observation devices suitable for the water environment, aquatic ecology, and water resource characteristics of arid and cold regions; and secondly, the scarcity of water resources and long ice-covered periods in lakes of these regions limit the exploration of methods for in-situ observation of aquatic plant degradation. Therefore, there is an urgent need for an in-situ degradation observation device and method for aquatic plants in lakes of arid and cold regions, providing research methods and scientific data support for addressing the widespread problem of aquatic plant degradation exacerbating endogenous pollution loads in these lakes. Summary of the Invention

[0004] The purpose of this invention is to provide an in-situ degradation observation device and method for aquatic plants in lakes in cold and arid regions, in order to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: an in-situ degradation observation device for aquatic plants in lakes in cold and arid regions, comprising a support base and three sets of plant degradation observation boxes installed on the support base and distributed in areas that include at least three regions: above the water surface, a fixed distance below the water surface, and underwater. Each set of plant degradation observation boxes can be detachably equipped with multiple degradation observation units, and the degradation observation units store aquatic plants corresponding to the lake.

[0006] Preferably, the degradation observation unit includes a splicing structure, a connecting rope, and a plant degradation net bag. The splicing structure is detachably installed inside the plant degradation observation box. The connecting rope is configured to connect the splicing structure and the plant degradation net bag and control the plant degradation net bag to be suspended inside the plant degradation observation box. The plant degradation net bag is used to store aquatic plants.

[0007] Preferably, the three sets of plant degradation observation boxes in three areas—above and below the water surface at a fixed distance, and underwater—are respectively a surface plant degradation observation box, an ice layer plant degradation observation box, and an underwater plant degradation observation box. The surface plant degradation observation box and the ice layer plant degradation observation box are both slidably mounted vertically on the support base. A floating platform is provided on the support base between the surface plant degradation observation box and the ice layer plant degradation observation box. The floating platform is connected to the surface plant degradation observation box and the ice layer plant degradation observation box via a fixed-length connecting rod, used to control the surface plant degradation observation box to always be located at a fixed distance above the water surface, and to control the ice layer plant degradation observation box to always be located at a fixed distance below the water surface.

[0008] Preferably, the degradation observation unit of the ice plant degradation observation box and the corresponding vertical degradation observation unit in the underwater plant degradation observation box are connected by a rope, which is used to remove the degradation observation unit of the ice plant degradation observation box and simultaneously remove the corresponding vertical degradation observation unit in the underwater plant degradation observation box.

[0009] Preferably, each degradation observation unit in the ice layer plant degradation observation box on the floating platform is provided with a guide channel, and a sleeve is inserted into each guide channel. In the observation state, the sleeve is pre-inserted to a position close to the top of the corresponding plant degradation net bag, and the inner diameter of the sleeve is configured to allow the plant degradation net bag to pass through.

[0010] Preferably, the guide channel and the outer wall of the sleeve are both provided with threads, which are engaged and installed together, and the sleeve has multiple protruding teeth circumferentially arranged at the end facing the aquatic plant.

[0011] Preferably, the sleeve has a sandwich structure, and a cavity is provided in the sandwich along the vertical direction. The top of the sleeve has an opening that communicates with the cavity and is used to inject liquid into the cavity.

[0012] Preferably, the underwater plant degradation observation box has a horizontal plate at its opening, and each horizontal plate has a through hole corresponding to each degradation observation unit.

[0013] A tube is fitted onto the rope near the plant-degradable net bag in the underwater plant degradation observation box. A first limiting block is positioned above the tube, and a second limiting block is positioned below the tube. The inner diameter of the tube is configured to allow the plant-degradable net bag to pass through. The tube is inserted into the through hole. A narrow opening is provided at the top of the tube. When the first limiting block contacts the narrow opening, the plant-degradable net bag is suspended inside the underwater plant degradation observation box. When the second limiting block enters the tube and contacts the narrow opening, it prevents the plant-degradable net bag from detaching from the tube and keeps the plant-degradable net bag inside the tube.

[0014] Preferably, an anti-settlement platform is provided on the support base below the underwater plant degradation observation box.

[0015] This invention also discloses a method for in-situ degradation observation of aquatic plants in lakes in cold and arid regions, using an in-situ degradation observation device for aquatic plants in lakes in cold and arid regions, including the following steps:

[0016] S1. Based on the lake type, determine the installation positions of the three sets of plant degradation observation boxes on the support base, and install waterproof temperature and light intensity recorders in all three sets of plant degradation observation boxes. At the same time, determine the types of aquatic plants to be stored.

[0017] S2. Install the observation device at the predetermined location;

[0018] S3. Every month, acquire in-situ degradation data of water temperature, air temperature and light intensity collected by the waterproof temperature and light intensity recorder in each plant degradation observation box.

[0019] S4. Every month, take out one set of degradation observation units, remove the aquatic plant debris, rinse it with deionized water and air dry it, and analyze the dry weight of the plant debris and the changes in the composition of substances including plant carbon, nitrogen and phosphorus.

[0020] S5. Repeat S3 and S4 monthly until all degradation observation units are removed;

[0021] S6. Based on in-situ field observations of changes in aquatic plant components at different times, the nutrient release rate during aquatic plant degradation is obtained using the following formula:

[0022] ;

[0023] Where R is the nutrient release rate during the degradation of a unit mass of aquatic plant straw; To observe the mass of aquatic plant straw in the initial degradation observation unit; To observe the nutrient content of aquatic plants in the initial degradation observation unit; The mass of aquatic plant straw in the degradation observation unit up to time t; The content of nutrient components in aquatic plants in the degradation observation unit up to time t.

[0024] Beneficial Effects: This invention addresses the challenges of long ice cover periods and unstable water levels in lakes in arid and cold regions. It comprehensively considers the different degradation characteristics of aquatic plants in the subsurface water, frozen layer, and air above the water. A supporting base and a three-tiered plant degradation observation box are designed, allowing for adjustments to the observation box and internal observation group layout based on different ice cover periods, temperatures, and water levels. This solves the problem of observing the in-situ degradation process of aquatic plants in lakes in arid and cold regions under different conditions. It is of great significance for studying the degradation process and mechanism of large amounts of aquatic plant litter in lakes in arid and cold regions, as well as for assessing endogenous pollution loads.

[0025] This invention, through the combination of a floating platform and an aquatic plant degradation observation box and an ice-layer plant degradation observation box, enables the aquatic plant degradation observation box and the ice-layer plant degradation observation box to remain in a preset position regardless of the water level, thereby allowing for more accurate and effective in-situ degradation process observation.

[0026] In addition, this invention designs a sleeve and a corresponding plant degradation net bag connection and installation method to address the characteristics of lakes in cold and arid regions during the ice-covered period. This allows for the rapid and complete acquisition of plant degradation net bags in each area during the ice-covered period without affecting plant degradation net bags in other locations, thus providing great convenience for the long-term, large-scale degradation process of aquatic plant litter in lakes in cold and arid regions. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to the present invention.

[0028] Figure 2 This is a schematic diagram of the internal structure of the observation device of the present invention;

[0029] Figure 3 This is a plan view of the interior of the observation device of the present invention;

[0030] Figure 4 This is a schematic diagram of the assembly of the sleeve, degradation observation unit, and insert of the present invention;

[0031] Figure 5This is a schematic diagram of the structure of the sleeve and multiple degradation observation units of the present invention;

[0032] Figure 6 This is a cross-sectional schematic diagram of the sleeve, degradation observation unit, and insert of the present invention;

[0033] Figure 7 This is a graph showing the changes in the dry matter weight and total nitrogen and total phosphorus content of plant straw.

[0034] Numbered in the diagram: 1. Support base; 2. Aquatic plant degradation observation box; 3. Ice layer plant degradation observation box; 4. Underwater plant degradation observation box; 51. Splicing structure; 52. Connecting rope; 53. Plant degradation net bag; 6. Nylon net; 7. Floating platform; 8. Fixed-length connecting rod; 9. Rope; 10. Horizontal plate; 11. Hole; 12. Guide channel; 13. Sleeve; 14. Thread; 15. Raised tooth; 16. Cavity; 17. Through hole; 18. Insert tube; 19. First limiting block; 20. Second limiting block; 21. Narrow opening; 22. Anti-settlement platform; 23. Waterproof baffle. Detailed Implementation

[0035] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0036] Example: Reference Figures 1-6 As shown, an in-situ degradation observation device for aquatic plants in lakes in cold and arid regions includes a support base 1 and three sets of plant degradation observation boxes installed on the support base 1, with a distribution area covering at least three regions: above the water surface, a fixed distance below the water surface, and underwater. These are a surface plant degradation observation box 2, an ice layer plant degradation observation box 3, and an underwater plant degradation observation box 4, used to observe the degradation process of aquatic plants in the air above water, within the ice layer, and underwater, respectively. Each set of plant degradation observation boxes contains multiple detachable degradation observation units, which store the corresponding aquatic plants of the lake. In this embodiment, the degradation observation unit includes a splicing structure 51, a connecting rope 52, and a plant degradation net bag 53. The splicing structure 51 is detachably installed inside the plant degradation observation box. The connecting rope 52 is configured to connect the splicing structure 51 and the plant degradation net bag 53, and controls the plant degradation net bag 53 to be suspended inside the plant degradation observation box. The plant degradation net bag 53 is used to store aquatic plants. The periphery of the plant degradation observation box is covered with a hole diameter of 1. cm nylon netting 6, to prevent fish, birds and other animals from damaging the plant degradation netting bag 53 inside the observation box.

[0037] In one embodiment, both the aquatic plant degradation observation box 2 and the ice plant degradation observation box 3 are slidably mounted on the support base 1 in a vertical direction. The plant degradation observation box as a whole can slide vertically along the support base 1. A floating platform 7 is provided on the support base 1 between the aquatic plant degradation observation box 2 and the ice plant degradation observation box 3. The floating platform 7 is connected to the aquatic plant degradation observation box 2 and the ice plant degradation observation box 3 by a fixed-length connecting rod 8, which is used to control the aquatic plant degradation observation box 2 to always be located at a fixed distance above the water surface, and to control the ice plant degradation observation box 3 to always be located at a fixed distance below the water surface, so as to avoid the aquatic plant degradation observation box 2 being submerged or the ice plant degradation observation box 3 being removed from the water surface due to changes in the lake water level, which would affect the observation results. Figure 1 As shown, the floating platform 7 is slidably installed on the support base 1. As the water level changes, the floating platform 7 is restricted to move vertically within the support base 1. This allows the aquatic plant degradation observation box 2 and the ice plant degradation observation box 3 to adaptively adjust their heights via the fixed-length connecting rod 8. The water level is always the base plane, maintaining the corresponding heights and ensuring that the ice plant degradation observation box 3 remains in a preset and reasonable position on the ice layer when the lake is frozen in winter.

[0038] refer to Figures 1-3 As shown, in this embodiment, the degradation observation units in the ice plant degradation observation box 3 and the corresponding vertical degradation observation units in the underwater plant degradation observation box 4 are connected by ropes 9, which are used to remove the degradation observation units in the ice plant degradation observation box 3 and simultaneously remove the corresponding vertical degradation observation units in the underwater plant degradation observation box 4.

[0039] For aquatic plant degradation observation box 2, refer to Figures 1-3 As shown, the top of the aquatic plant degradation observation box 2 is open, and several horizontal plates 10 are installed at the opening. Each horizontal plate 10 has several holes 11. The splicing structure 51 here adopts a T-shaped insert structure. The plant degradation net bag 53 passes through the holes 11 and enters the aquatic plant degradation observation box 2. It is fixed by inserting the insert structure into the holes 11, so that the plant degradation net bag 53 is suspended in the aquatic plant degradation observation box 2. When removing it, the insert structure is pulled out and the corresponding plant degradation net bag 53 is taken out.

[0040] To address the challenge of extracting degradation observation units from the ice layer during periods of ice cover, in one embodiment, reference is made to... Figure 1 and Figures 4-6On the floating platform 7, guide channels 12 are provided at corresponding locations of each degradation observation unit within the ice-layer plant degradation observation box 3. A connecting rope 52 is inserted into each guide channel 12. During observation, a sleeve 13 is pre-inserted close to the corresponding plant degradation net bag 53. The inner diameter of the sleeve 13 is configured to allow the plant degradation net bag 53 to pass through. The splicing structure 51 of the degradation observation units in the ice-layer plant degradation observation box 3 and the underwater plant degradation observation box 4 uses the same T-shaped insert structure. Two plant degradation net bags 53 are connected by a rope 9 and suspended inside the ice-layer plant degradation observation box 3 and the underwater plant degradation observation box 4 via the sleeve 13 installed in the guide channel 12. The top of each bag is inserted into the top of the sleeve 13 via the insert structure. To remove the bag, the insert structure is pulled out, and the corresponding plant degradation net bag 53 is removed. In this embodiment, the guide channel... Both the inner wall of the channel 12 and the outer wall of the sleeve 13 are provided with threads 14, which are engaged for installation. The sleeve 13 has multiple protruding teeth 15 circumferentially arranged on the end facing the aquatic plant. During the ice-covered period, it is only necessary to remove the insert structure and then rotate the sleeve 13. The engagement of the threads 14 causes the sleeve 13 to move downwards, and with the help of the protruding teeth 15, the sleeve 13 can continuously drill downwards until it penetrates the ice layer. This allows the ice column containing the plant degradation net bag 53 to be completely obtained. The entire drilling process will not affect other degradation observation units in the ice layer plant degradation observation box 3, minimizing the disturbance to the ice layer plant degradation observation box 3. In this embodiment, the pre-insertion setting of the sleeve 13 can, on the one hand, use the ice layer to pre-fix the sleeve 13, so that it can drill along the specified direction and stably obtain the plant degradation net bag 53 below. On the other hand, it reduces the travel distance of the entire sleeve 13 and improves the acquisition efficiency.

[0041] In another embodiment, reference Figure 6 As shown, the sleeve 13 has a sandwich structure, and a cavity 16 is provided in the sandwich along the vertical direction. The top of the sleeve 13 has an opening that communicates with the cavity 16. The opening is used to inject liquid into the cavity 16. The liquid poured in can pre-melt the contact surface between the outer wall of the sleeve 13 and the ice layer, thereby separating the outer wall of the sleeve 13 from the ice layer to facilitate the next drilling operation.

[0042] In another embodiment, a horizontal plate 10 is provided at the opening of the underwater plant degradation observation box 4. Through holes 17 are provided on the horizontal plate 10 at locations corresponding to each degradation observation unit. An insert 18 is fitted onto the rope 9 near the plant degradation net bag 53 of the underwater plant degradation observation box 4. The top and bottom of the insert 18 are open. A first limiting block 19 is provided above the insert 18 on the rope 9, and a second limiting block 20 is provided below the insert 18. The inner diameter of the insert 18 is configured to accommodate at least the plant degradation net bag. The bag 53 passes through; the insert 18 is used to insert into the through hole 17. The top opening of the insert 18 is provided with a narrow opening 21. When the first limiting block 19 contacts the narrow opening 21, the plant degradation net bag 53 is suspended in the underwater plant degradation observation box 4. When the second limiting block 20 enters the insert 18 and contacts the narrow opening 21, it restricts the plant degradation net bag 53 from detaching from the insert 18 and keeps the plant degradation net bag 53 inside the insert 18. Based on the configuration of this embodiment, the plant degradation net is placed into the underwater plant degradation observation box 4 through the through hole 17. After being removed from the observation box 4, the insert 18 serves as the splicing structure 51 of the underwater plant degradation observation unit 4. The insert 18 has a T-shaped cross-section and is fixed in position by being inserted into the through hole 17. At the same time, the first limiting block 19 prevents the plant degradation net from moving further downward, suspending the plant degradation net inside the underwater plant degradation observation box 4. In this embodiment, the use of the insert 18 can reduce the swing amplitude of the plant degradation net below, preventing it from swaying too much due to currents underwater, thus avoiding collisions and entanglements with adjacent plant degradation nets. On the other hand, when it is removed, the insert 18 remains stationary in the through hole 17, and the plant degradation net moves upward under the traction of the connecting rope 52 until the second limiting block 20 contacts the narrow opening 21. At this point, the plant degradation net enters the insert 18, and then the insert 18 moves upward synchronously with the connecting rope 52, thus ensuring that the plant degradation net is protected by the insert 18 during the entire upward movement process and reducing the risk of damage during movement.

[0043] In one embodiment, an anti-settlement platform 22 is provided on the support base 1 below the underwater plant degradation observation box 4. A waterproof baffle 23 can be installed on the lower part of the above-water plant degradation observation box 2 to prevent the impact of wind and waves on the degradation of the above-water plants. An organic glass rain cover can be installed on the top of the support base 1 to prevent atmospheric deposition from affecting the above-water plant degradation observation box 2.

[0044] In another embodiment, a method for in-situ degradation observation of aquatic plants in lakes in cold and arid regions is disclosed. The method uses the aforementioned observation device and includes the following steps:

[0045] S1. Based on the lake type, determine the installation positions of the three sets of plant degradation observation boxes on the support base 1, and install waterproof temperature and light intensity recorders in the three sets of plant degradation observation boxes. At the same time, determine the types of aquatic plants to be stored.

[0046] S2. Install the observation device at the predetermined location;

[0047] S3. Every month, acquire in-situ degradation data of water temperature, air temperature and light intensity collected by the waterproof temperature and light intensity recorder in each plant degradation observation box.

[0048] S4. Every month, take out one set of degradation observation units, remove the aquatic plant debris, rinse it with deionized water and air dry it, and analyze the dry weight of the plant debris and the changes in the composition of substances including plant carbon, nitrogen and phosphorus.

[0049] S5. Repeat S3 and S4 monthly until all degradation observation units are removed;

[0050] S6. Based on in-situ field observations of changes in aquatic plant components at different times, the nutrient release rate during aquatic plant degradation is obtained using the following formula:

[0051] ;

[0052] Where R is the nutrient release rate during the degradation of a unit mass of aquatic plant straw, in mg / (gd); The mass of aquatic plant straw in the initial degradation observation unit is measured in grams. The content of nutrient components in aquatic plants in the initial degradation observation unit is measured in mg / kg. The mass of aquatic plant straw in the degradation observation unit up to time t is expressed in grams. The content of nutrient components in aquatic plants in the degradation observation unit up to time t is expressed in mg / kg.

[0053] This application also provides a specific embodiment of the installation and implementation process in a lake in a cold and arid region:

[0054] The selected lake is a typical eutrophic lake of grass type in a cold and arid region. The dominant aquatic plant species is reed, and the average water depth of the lake is about 2 m. Due to the long-term overgrowth and death of aquatic plants, the lake bottom sediment is seriously polluted, and the soft polluted silt is quite deep.

[0055] (1) Investigation of water depth and soft silt depth in the target area; The area about 1 km from the lake shore was selected as the area for in-situ degradation observation of aquatic plants. Through preliminary investigation, the water depth at the target location was 1.9 m, the soft silt depth was about 40 cm, and the top 15 cm was mostly floating mud with a water content of more than 70%. The floating mud was mainly composed of aquatic plant debris, indicating that the area was greatly affected by the long-term excessive growth and death of aquatic plants, resulting in prominent endogenous pollution of the bottom sediment.

[0056] (2) Based on the depth of soft silt, the height of the support base 1 fixing rod is customized to 50 cm, with the fixing rod protruding about 10 cm from the silt. The anti-settlement platform 22 with a thickness of 4 mm is installed about 5 cm above the mud-water interface.

[0057] (3) Use stainless steel pipes with an outer diameter of 2 cm to construct a frame. The frame is 60 cm long, 50 cm wide, and 40 cm high. Construct three parts of the frame: underwater plant degradation observation box 4, ice layer plant degradation observation box 3, and above-water plant degradation observation box 2. Cover the perimeter of the frame with nylon netting with a pore size of 1 cm.

[0058] Select air-dried reed stalks, cut them into small sections about 5 cm long, randomly sample 30.00 g, put them into an 80-mesh (177 μm aperture) plant degradation mesh, and mark them in sequence; select 3 parallel plant degradation meshes;

[0059] The underwater plant degradation observation box 4 is fixed 5 cm above the anti-settlement platform 22; according to historical meteorological data, the ice thickness of the lake in winter is about 60 cm, so the ice layer plant degradation observation box 3 is fixed about 30 cm below the water surface; the above-water plant degradation observation box 2 is fixed about 50 cm above the water surface. In addition, a waterproof baffle 23 can be installed 10 cm below the bottom of the above-water plant degradation observation box 2.

[0060] (4) A year-long in-situ field observation was conducted in the lake, with samples taken every 30 days. The changes in the dry matter weight of plant straw and the total nitrogen and total phosphorus content were observed as follows: Figure 7 As shown, the mass loss of plant straw during degradation at different locations—underwater, on ice, and above water—exhibited significant differences. Underwater, the mass loss was the fastest and greatest within a one-year degradation cycle, followed by the ice layer, while the mass loss was smallest in the air above water. Regarding the nitrogen and phosphorus content of the straw, both underwater and on ice showed a phenomenon of first decreasing and then increasing. This indicates that straw degradation in water may involve initial release followed by adsorption. In the air above water, the nitrogen and phosphorus content of straw remained relatively stable overall. Using this device, three sets of plant degradation observation boxes—underwater, on ice, and above water—simultaneously observed the plant degradation process in different areas (underwater and above water) and at different times (frozen and unfrozen periods) of lakes in arid and cold regions. This demonstrates significant advancements and solves the challenge of observing the in-situ degradation process of aquatic plants in lakes in arid and cold regions under different conditions. It is of great significance for studying the degradation process and mechanism of large amounts of aquatic plant litter in arid and cold regions.

[0061] The embodiments of the present invention have been described in detail above with reference to the examples. However, the present invention is not limited to the above embodiments. For those skilled in the art, after learning the contents described in the present invention, several equivalent changes and substitutions can be made without departing from the principle of the present invention. These equivalent changes and substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. An in-situ degradation observation device for aquatic plants in lakes in cold and arid regions, characterized in that: The system includes a support base and three sets of plant degradation observation boxes installed on the support base, with the distribution area covering at least three regions: above the water surface, a fixed distance below the water surface, and underwater. Each set of plant degradation observation boxes can be detachably equipped with multiple degradation observation units, and the degradation observation units store aquatic plants corresponding to the lake.

2. The in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to claim 1, characterized in that: The degradation observation unit includes a splicing structure, a connecting rope, and a plant degradation net bag. The splicing structure is detachably installed inside the plant degradation observation box. The connecting rope is configured to connect the splicing structure and the plant degradation net bag and control the plant degradation net bag to be suspended inside the plant degradation observation box. The plant degradation net bag is used to store aquatic plants.

3. The in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to claim 2, characterized in that: The three sets of plant degradation observation boxes, located at a fixed distance above and below the water surface and in three underwater areas, are respectively an above-water plant degradation observation box, an ice-covered plant degradation observation box, and an underwater plant degradation observation box. The above-water and ice-covered plant degradation observation boxes are slidably mounted vertically on the support base. A floating platform is provided on the support base between the above-water and ice-covered plant degradation observation boxes. The floating platform is connected to the above-water and ice-covered plant degradation observation boxes via a fixed-length connecting rod, used to control the above-water plant degradation observation box to always be located at a fixed distance above the water surface, and to control the ice-covered plant degradation observation box to always be located at a fixed distance below the water surface.

4. The in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to claim 3, characterized in that: The degradation observation unit of the ice plant degradation observation box and the corresponding vertical degradation observation unit in the underwater plant degradation observation box are connected by ropes, which are used to remove the degradation observation unit of the ice plant degradation observation box and simultaneously remove the corresponding vertical degradation observation unit in the underwater plant degradation observation box.

5. The in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to claim 4, characterized in that: On the floating platform, each degradation observation unit in the ice layer plant degradation observation box is provided with a guide channel. A sleeve is inserted into each guide channel. In the observation state, the sleeve is pre-inserted to a position close to the top of the corresponding plant degradation net bag. The inner diameter of the sleeve is configured to allow the plant degradation net bag to pass through at least.

6. The in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to claim 5, characterized in that: Both the guide channel and the outer wall of the sleeve are provided with threads, which are engaged and installed together. The sleeve has multiple protruding teeth circumferentially on the end facing the aquatic plant.

7. The in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to claim 5, characterized in that: The sleeve has a sandwich structure, and a cavity is provided in the sandwich along the vertical direction. The top of the sleeve has an opening that communicates with the cavity and is used to inject liquid into the cavity.

8. The in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to claim 4, characterized in that: The underwater plant degradation observation box has a horizontal plate at its opening, and each horizontal plate has a through hole corresponding to each degradation observation unit. A tube is fitted onto the rope near the plant-degradable net bag in the underwater plant degradation observation box. A first limiting block is positioned above the tube, and a second limiting block is positioned below the tube. The inner diameter of the tube is configured to allow the plant-degradable net bag to pass through. The tube is inserted into the through hole. A narrow opening is provided at the top of the tube. When the first limiting block contacts the narrow opening, the plant-degradable net bag is suspended inside the underwater plant degradation observation box. When the second limiting block enters the tube and contacts the narrow opening, it prevents the plant-degradable net bag from detaching from the tube and keeps the plant-degradable net bag inside the tube.

9. The in-situ degradation observation device for aquatic plants in lakes in cold and arid regions according to claim 3, characterized in that: An anti-settlement platform is installed on the support base below the underwater plant degradation observation box.

10. A method for in-situ observation of the degradation of aquatic plants in lakes in cold and arid regions, characterized in that, The observation using the in-situ degradation observation device for aquatic plants in cold and arid lakes according to any one of claims 1-9 includes the following steps: S1. Based on the lake type, determine the installation positions of the three sets of plant degradation observation boxes on the support base, and install waterproof temperature and light intensity recorders in all three sets of plant degradation observation boxes. At the same time, determine the types of aquatic plants to be stored. S2. Install the observation device at the predetermined location; S3. Every month, acquire in-situ degradation data of water temperature, air temperature and light intensity collected by the waterproof temperature and light intensity recorder in each plant degradation observation box. S4. Every month, take out one set of degradation observation units, remove the aquatic plant debris, rinse it with deionized water and air dry it, and analyze the dry weight of the plant debris and the changes in the composition of substances including plant carbon, nitrogen and phosphorus. S5. Repeat S3 and S4 monthly until all degradation observation units are removed; S6. Based on in-situ field observations of changes in aquatic plant components at different times, the nutrient release rate during aquatic plant degradation is obtained using the following formula: ； Where R is the nutrient release rate during the degradation of a unit mass of aquatic plant straw; To observe the mass of aquatic plant straw in the initial degradation observation unit; To observe the nutrient content of aquatic plants in the initial degradation observation unit; The mass of aquatic plant straw in the degradation observation unit up to time t; The content of nutrient components in aquatic plants in the degradation observation unit up to time t.

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