A device and measurement method for monitoring greenhouse gas fluxes at the sediment-water interface

Abstract

This invention relates to the field of water body monitoring technology and discloses a monitoring device and measurement method for greenhouse gas flux at the sediment-water interface. The monitoring device includes one gas-water monitoring box and three gas monitoring boxes. The gas-water monitoring box and the three gas monitoring boxes are installed on the same slide rail via sliding connectors. The gas-water monitoring box and the three gas monitoring boxes are hollow and have fixed plates movably connected to their bottom surfaces. The gas-water monitoring box and the gas monitoring box are equipped with a filter structure inside. The gas monitoring box is equipped with an exhaust structure inside. The outer wall of the gas monitoring box is connected to a gas sampling structure. This invention provides accurate sampling, simple operation, adaptability to various aquatic environments, and enables in-situ continuous collection of greenhouse gases at the sediment-water interface, making it highly practical.

Description

Technical Field

[0001] This invention relates to the field of water body monitoring technology, and in particular to a device and method for monitoring greenhouse gas flux at the sediment-water interface. Background Technology

[0002] In recent years, with the accelerating pace of industrialization, the impact of global warming caused by greenhouse gas emissions on human life has become increasingly significant, leading to greater concern about the sources and control of greenhouse gas emissions. Freshwater ecosystems, as one of the Earth's major ecosystems, are not only an important component of the global carbon and nitrogen cycle but also a significant natural source of global greenhouse gas emissions. Seabed sediments, rich in organic matter and nitrogen nutrients, are the primary sites of matter and energy metabolism in aquatic ecosystems and a major source of greenhouse gas production in freshwater lakes. The sediment-water interface, as a necessary link in sediment greenhouse gas emissions, makes accurate monitoring of its dynamic changes in greenhouse gas flux crucial for understanding the influencing factors of greenhouse gas emissions.

[0003] Traditional methods for obtaining greenhouse gas fluxes at the sediment-water interface mainly include: (1) Boundary layer model method (diffusion model method). The flux is calculated by measuring the gas concentration in sediment pore water and lake bottom water using diffusion formulas. Disadvantages include: a. Difficulty in collecting pore water; b. Complex operation and sample contamination in the water sample extraction process; c. Only the diffusion flux at the sediment-water interface can be obtained, ignoring the flux emitted in the form of bubbling; d. The diffusion formula has many design parameters, and the selection of relevant parameters relies on the derivation of empirical formulas, resulting in large calculation errors. (2) Indoor culture method. Disadvantages include: a. During the indoor culture simulation by collecting sediment samples, it is impossible to simulate the effects of physical and biological disturbances such as water level, wind speed, pressure, and biological disturbances under natural conditions; b. The original physicochemical and biological properties of the sediment may be damaged during the sample collection process.

[0004] In summary, the currently developed sediment-water interface greenhouse gas flux monitoring devices have the following problems, which affect the accuracy of greenhouse gas flux monitoring: a. They ignore the interference of gas samples captured by the sampler during the sinking and rising of the sampling device on the actual collected sediment-water interface gas samples; b. The design of the device does not consider the influence of hydrostatic pressure and the original gas in the gas delivery pipe; c. They cannot continuously sample and observe.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a greenhouse gas flux monitoring device and measurement method at the sediment-water interface. It features accurate sampling, simple operation, adaptability to various aquatic environments, and the ability to achieve in-situ continuous collection of greenhouse gases at the sediment-water interface, making it highly practical.

[0007] To achieve the above objectives, this application employs the following technical solution:

[0008] In a first aspect, a greenhouse gas flux monitoring device for sediment-water interface is provided, characterized in that it includes a gas-water monitoring box and a gas monitoring box;

[0009] The gas-water monitoring box and the gas monitoring box are installed on the same slide rail by sliding connectors and controlled by buckles. The gas-water monitoring box and the gas monitoring box are hollow and the bottom surface is connected to a fixing device for fixing the gas-water monitoring box and the gas monitoring box.

[0010] The gas-water monitoring box and the gas monitoring box are equipped with a filtration structure to filter the water and gas entering the gas-water monitoring box and the gas monitoring box. The gas monitoring box is equipped with an exhaust structure to discharge the gas entering the gas monitoring box. The outer wall of the gas monitoring box is connected to the gas sampling structure. The side of the gas-water monitoring box is equipped with a water outlet.

[0011] Optionally, the fixing device includes a control structure and a movable fixing plate, the fixing plate being adjustablely connected to the gas monitoring box via the control structure.

[0012] Optionally, the control structure includes a spring clip, a locking strip, and a pull rope. The spring clip is disposed in the middle of the fixed plate, the locking strip is disposed on the side of the fixed plate, and the spring clip is connected to the pull rope.

[0013] Optionally, the filtration structure includes a filter membrane and support plates, with two support plates sandwiched between the filter membrane.

[0014] Optionally, the filter membrane includes a PTFE membrane and a one-way permeable geomembrane, wherein the filter membrane in the gas monitoring box is a PTFE membrane and the filter membrane in the gas-water monitoring box is a one-way permeable geomembrane.

[0015] Optionally, the exhaust structure includes a pull rod and a piston, the piston being installed inside the gas monitoring box, the piston being connected to the pull rod, and the pull rod extending out of the gas monitoring box.

[0016] Optionally, the gas sampling structure is a gas bag, and a gas sampling hole is provided on the side wall of the gas monitoring box. The gas bag is connected to the gas monitoring box through the gas sampling hole.

[0017] Optionally, an oil layer is applied to the connection of the fixing plate, an oil layer is applied to the hole through which the tie rod passes on the side wall of the gas-water monitoring box, and an oil layer is applied to the gas sampling hole on the side wall of the gas monitoring box.

[0018] Secondly, a method for measuring greenhouse gas fluxes at the water-sediment interface is provided, which is implemented using a water-sediment interface greenhouse gas flux monitoring device.

[0019] The length of the slide rail is adjusted according to the water depth, and the gas-water monitoring box and the three gas monitoring boxes are installed on the slide rail by buckles.

[0020] Slowly lower the entire device into the water. When the device is close to the bottom, manipulate the fixing device to vertically insert it into the sediment to secure the entire device.

[0021] Atmospheric samples were collected from the water surface at the sampling site using the gas sampling structure, and the concentration of greenhouse gases was denoted as C0.

[0022] Gas and water collection begins when the bottom of the device coincides with the sediment-water interface, and the start time T0 is recorded. Water gradually passes through the filter structure and enters the gas and water monitoring box. Gas generated by the sediment in the area covered by the gas monitoring box passes through the filter structure and enters the three gas monitoring boxes respectively.

[0023] After the collection period is over, adjust the buckle so that the gas-water monitoring box and the gas monitoring box can slide up and down on the slide rail. Pull the rope connected to the gas-water monitoring box and the gas monitoring box to remove a single gas-water monitoring box or gas monitoring box.

[0024] At sampling time T 2-1 T 2-2 and T 2-3 At that time, the three gas monitoring boxes can be taken out in sequence, and the gas in the monitoring box can be pushed into the gas sampling structure through the exhaust structure;

[0025] At the end of sampling T 2-3 Simultaneously remove the gas-water monitoring box and use a pump to send the water sample from the box into the collection bottle to complete the entire sampling process.

[0026] The CO concentration of the collected atmospheric samples and the greenhouse gas concentration C in the three gas monitoring chambers were determined using a laboratory gas chromatograph. 2-1 C 2-2 and C 2-3 ;

[0027] Calculate the greenhouse gas diffusion flux F at the sediment-water interface in each of the three gas monitoring chambers. 2-1 F 2-2 and F 2-3 The calculation formula is as follows:

[0028] ;

[0029] ;

[0030] ;

[0031] In the formula, V is the volume of a single gas monitoring box; A is the bottom area of ​​a single gas monitoring box; C 2-1 , C 2-2 and C 2-3 The values ​​represent the gas concentration differences before and after sample collection in the three gas monitoring chambers, with atmospheric concentration as the initial concentration C0. T 2-1 , T 2-2 and T 2-3 These represent the time intervals for collecting samples from the three gas monitoring chambers.

[0032] Take F 2-1 F 2-2 and F 2-3 The arithmetic mean can be used as the average greenhouse gas diffusion flux F2 at the sediment-water interface at this monitoring point, as shown in the formula:

[0033] ;

[0034] Greenhouse gases in water samples collected in a gas-water monitoring chamber were collected using the headspace balance method, and their concentrations were determined using gas chromatography.

[0035] ;

[0036] ;

[0037] In the formula, C w Dissolved gas concentration in water sample; C1 is the gas concentration measured after headspace equilibrium; C0 is the atmospheric background concentration; V0 is the headspace air volume / L; V1 is the water sample volume used for headspace measurement / L; R is the universal gas constant; T is the water temperature / K; K0 is the gas solubility coefficient; A1, A2, and A3 are constants.

[0038] The total greenhouse gas flux F1 entering the gas-water monitoring chamber through both diffusion and bubbling at the bottom is calculated using the following formula:

[0039] ;;

[0040] In the formula, V is the volume of the gas-water monitoring box; A is the bottom area of ​​the gas-water monitoring box; Cw The concentration of dissolved gases in the water sample in the gas-water monitoring chamber; T 2-3 The time interval for collecting samples from the gas-water monitoring box.

[0041] Calculate the time-varying average bubbling flux F of greenhouse gases at the sediment-water interface at this location. 2-1泡 F 2-2泡 and F 2-3泡 and total average bubbling flux F 1泡 The formula is

[0042] ;

[0043] ;

[0044] ;

[0045] .

[0046] Compared with the prior art, the beneficial effects achieved by this application are as follows:

[0047] By setting the length of the slide rail, precise in-situ sampling of gases at the underwater sediment-water interface at any depth can be achieved.

[0048] It can collect gas samples at different times as needed, is easy to operate, has high feasibility, and can distinguish between gas diffusion flux and bubbling flux;

[0049] When collecting gas samples, simply adjusting the exhaust structure is sufficient to send all the collected gas into the gas bag, greatly improving the sampling accuracy. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a plan view of an embodiment of a sediment-water interface greenhouse gas flux monitoring device and metering method according to the present invention;

[0052] Figure 2 This is a front view of an embodiment of a sediment-water interface greenhouse gas flux monitoring device and metering method according to the present invention;

[0053] Figure 3This is a cross-sectional view provided in an embodiment of a sediment-water interface greenhouse gas flux monitoring device and metering method according to the present invention;

[0054] Figure 4 This is a schematic diagram of the gas monitoring box structure provided in an embodiment of a sediment-water interface greenhouse gas flux monitoring device and metering method according to the present invention;

[0055] Figure 5 This is a schematic diagram of the gas-water monitoring box structure provided in an embodiment of a sediment-water interface greenhouse gas flux monitoring device and metering method according to the present invention;

[0056] Figure 6 This is a top view of the fixed plate provided in an embodiment of a sediment-water interface greenhouse gas flux monitoring device and metering method according to the present invention;

[0057] Figure 7 This is a side view of the fixed plate provided in an embodiment of a sediment-water interface greenhouse gas flux monitoring device and metering method according to the present invention.

[0058] The markings in the diagram are as follows: 1. Gas-water monitoring box; 2. Gas monitoring box; 3. Gas sampling hole; 4. Water outlet; 5. Buckle; 6. Slide rail; 7. Fixing plate; 8. Pull rod outlet; 9. Piston; 10. Pull rod; 11. Support plate; 12. PTFE membrane; 13. One-way permeable geomembrane; 14. Spring buckle; 15. Positioning strip; 16. Pull rope. Detailed Implementation

[0059] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use.

[0060] Example 1:

[0061] A sediment-water interface greenhouse gas flux monitoring device, such as Figures 1-5As shown, the system includes a water-gas monitoring box 1 and a gas monitoring box 2. The water-gas monitoring box 1 and the gas monitoring box 2 are mounted on the same slide rail 6 via a sliding connector and controlled by a buckle 5. Both the water-gas monitoring box 1 and the gas monitoring box 2 are hollow, and their bottom surfaces are connected to fixing devices for securing them. The interiors of both the water-gas monitoring box 1 and the gas monitoring box 2 are equipped with filtration structures to filter the water and gas entering them. The interior of the gas monitoring box 2 is equipped with an exhaust structure to discharge the gas entering it. The outer wall of the gas monitoring box 2 is connected to a gas sampling unit. The structure includes a water outlet 4 on the side of the gas-water monitoring box 1. By placing the gas-water monitoring box 1 and three gas monitoring boxes 2, which are installed on the slide rail 6, into the water and adjusting the positions of the gas-water monitoring box 1 and the three gas monitoring boxes 2 on the slide rail 6 according to the water depth, accurate in-situ field collection of gas at the underwater sediment-water interface at any depth can be achieved. The three gas monitoring boxes 2 can be set up to collect gas samples at different times as needed, which is convenient to operate and highly feasible. It can distinguish between gas diffusion flux and bubbling flux. When collecting gas samples, only the exhaust structure needs to be pulled to send the collected gas into the gas bag, which greatly improves the sampling accuracy.

[0062] The fixing device includes a control structure and a movable fixing plate 7. The fixing plate 7 is adjustablely connected to the gas monitoring box 2 through the control structure. When the entire device enters the water body, the fixing plate 7 does not open, the device is sealed, and it is not affected by various external conditions.

[0063] The filtration structure includes a filter membrane and support plates 11. Two support plates 11 are sandwiched on both sides of the filter membrane. The filter membrane includes a PTFE membrane 12 and a one-way permeable geomembrane 13. The filter membrane in the gas monitoring box 2 is a PTFE membrane, and the filter membrane in the gas-water monitoring box 1 is a one-way permeable geomembrane 13. Impurities in the sediment are filtered through the filter membrane. Depending on what needs to be collected in the box, a PTFE membrane or a one-way permeable geomembrane 13 is used.

[0064] The exhaust structure includes a pull rod 10 and a piston 9. The piston 9 is installed inside the gas monitoring box 2 and is connected to the pull rod 10. The pull rod 10 extends out of the gas monitoring box 2. By pulling the pull rod 10, the piston 9 is driven to collect the gas inside the gas-water monitoring box 1 into the gas collection structure, which is convenient for control.

[0065] The gas sampling structure is a gas bag. A gas sampling hole 3 is provided on the side wall of the gas monitoring box 2. The gas bag is connected to the gas monitoring box 2 through the gas sampling hole 3 to facilitate the collection of the gas to be tested.

[0066] Apply an oil layer to the connection of the fixing plate 7, apply an oil layer to the hole through which the tie rod 10 passes on the side wall of the gas and water monitoring box 1, and apply an oil layer to the gas sampling hole 3 on the side wall of the gas monitoring box 2 to ensure the airtightness of the entire device during the collection process.

[0067] like Figures 6-7 As shown, the control structure includes a spring clip 14, a locking strip 15, and a pull rope 16. The spring clip 14 is located in the middle of the fixed plate 7, and the locking strip 15 is located on the side of the fixed plate 7. The spring clip is connected to the pull rope 16. After the device sinks, the pull rope 16 is pulled to open the spring clip 14, and the fixed plate 7 hangs down naturally and is locked by the locking strip 15, and is inserted vertically.

[0068] Example 2:

[0069] Based on Example 1, an implementation method for a sediment-water interface greenhouse gas flux monitoring device and metering method is provided:

[0070] like Figures 1-7 As shown, this is achieved through a greenhouse gas flux monitoring device at the sediment-water interface.

[0071] Adjust the length of slide rail 6 according to the water depth, and install gas-water monitoring box 1 and three gas monitoring boxes 2 on slide rail 6 through buckle 5;

[0072] Slowly lower the entire device into the water. When the device is close to the bottom, manipulate the fixing device to vertically insert it into the sediment to secure the entire device.

[0073] Atmospheric samples were collected at a depth of 0.5 m above the water surface at this site using a gas sampling structure, and the concentration of greenhouse gases was denoted as C0.

[0074] Gas and water collection begins when the bottom of the device coincides with the sediment-water interface, and the start time T0 is recorded. Water gradually passes through the filter structure and enters the gas and water monitoring box 1. Gas generated by the sediment in the area covered by the gas monitoring box 2 passes through the filter structure and enters the three gas monitoring boxes 2 respectively.

[0075] After the collection period is over, adjust the buckle so that the gas-water monitoring box 1 and the gas monitoring box 2 can slide up and down on the slide rail. Pull the rope connected to the gas-water monitoring box 1 and the gas monitoring box 2 to remove a single gas-water monitoring box 1 or gas monitoring box 2.

[0076] At sampling time T 2-1 T 2-2 and T 2-3 At this time, the three gas monitoring boxes 2 can be taken out in sequence, and the gas in the monitoring box can be pushed into the gas sampling structure through the exhaust structure;

[0077] At the end of sampling T 2-3 Simultaneously remove the air-water monitoring box 1, and use a pump to send the water sample from the box into the collection bottle to complete the entire sampling process.

[0078] The concentrations of greenhouse gases C0 in collected atmospheric samples and C2 in three gas monitoring chambers were determined using a laboratory gas chromatograph. 2-1 C 2-2 and C2-3 ;

[0079] Calculate the greenhouse gas diffusion flux F at the sediment-water interface in each of the three gas monitoring chambers 2. 2-1 F 2-2 and F 2-3 The calculation formula is as follows:

[0080] ;

[0081] ;

[0082] ;

[0083] In the formula, V is the volume of a single gas monitoring box 2; A is the bottom area of ​​a single gas monitoring box 2; C 2-1 , C 2-2 and C 2-3 The values ​​represent the gas concentration differences before and after sample collection in the three gas monitoring chambers 2, with atmospheric concentration as the initial concentration C0. T 2-1 , T 2-2 and T 2-3 These represent the time intervals at which samples are collected from the three gas monitoring chambers 2;

[0084] Take F 2-1 F 2-2 and F 2-3 The arithmetic mean can be used as the average greenhouse gas diffusion flux F2 at the sediment-water interface at this monitoring point, as shown in the formula:

[0085] ;

[0086] Greenhouse gases in water samples collected in gas-water monitoring chamber 1 were collected using headspace method, and their concentrations were determined using gas chromatography.

[0087] ;

[0088] ;

[0089] In the formula, C w Dissolved gas concentration in water sample; C1 is the gas concentration measured after headspace equilibrium; C0 is the atmospheric background concentration; V0 is the headspace air volume / L; V1 is the water sample volume used for headspace measurement / L; R is the universal gas constant; T is the water temperature / K; K0 is the gas solubility coefficient; A1, A2, and A3 are constants.

[0090] The total greenhouse gas flux F1 entering the gas-water monitoring chamber 1 through both diffusion and bubbling at the bottom is calculated using the following formula:

[0091]

[0092] In the formula, V is the volume of the gas-water monitoring box 1; A is the bottom area of ​​the gas-water monitoring box 1; C w The concentration of dissolved gases in the water of sample 1 in the gas-water monitoring chamber; T 2-3 The time interval for collecting samples from the gas-water monitoring box 1.

[0093] Calculate the time-varying average bubbling flux F of greenhouse gases at the sediment-water interface at this location. 2-1泡 F 2-2泡 and F 2-3泡 and total average bubbling flux F 1泡 The formula is

[0094] ;

[0095] ;

[0096] ;

[0097] .

[0098] Unlike Example 1, the greenhouse gas concentrations in three gas monitoring boxes 2 can be obtained during the monitoring process. Different gas monitoring boxes 2 can collect the concentrations of greenhouse gases in the water body at different times, enabling the present invention to achieve continuous collection and more accurate sampling and calculation results.

[0099] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific orientation. If the specific orientation changes, the directional indication will also change accordingly. These terms are used only for the convenience of describing this application and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0100] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0101] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A device for monitoring greenhouse gas fluxes at the sediment-water interface, characterized in that, Includes a gas-water monitoring box (1) and a gas monitoring box (2); The gas-water monitoring box (1) and the gas monitoring box (2) are installed on the same slide rail (6) by a sliding connector and controlled by a buckle (5). The gas-water monitoring box (1) and the gas monitoring box (2) are hollow and the bottom surface is connected to a fixing device for fixing the gas-water monitoring box (1) and the gas monitoring box (2). The gas-water monitoring box (1) and the gas monitoring box (2) are equipped with a filtration structure to filter the water and gas entering the gas-water monitoring box (1) and the gas monitoring box (2). The gas monitoring box (2) is equipped with an exhaust structure to discharge the gas entering the gas monitoring box (2). The outer wall of the gas monitoring box (2) is connected to the gas sampling structure. The gas-water monitoring box (1) is equipped with a water outlet (4) on its side. The fixing device includes a control structure and a movable fixing plate (7), which is adjustablely connected to the gas monitoring box (2) through the control structure; The control structure includes a spring buckle (14), a locking strip (15), and a pull rope (16). The spring buckle (14) is located in the middle of the fixed plate (7), the locking strip (15) is located on the side of the fixed plate (7), and the spring buckle (14) is connected to the pull rope (16).

2. The sediment-water interface greenhouse gas flux monitoring device according to claim 1, characterized in that, The filtration structure includes a filter membrane and two support plates (11), with the two support plates (11) sandwiched between the two sides of the filter membrane.

3. The sediment-water interface greenhouse gas flux monitoring device according to claim 2, characterized in that, The filter membrane includes a PTFE membrane (12) and a one-way permeable geomembrane (13). The filter membrane in the gas monitoring box (2) is a PTFE membrane, and the filter membrane in the gas-water monitoring box (1) is a one-way permeable geomembrane (13).

4. The sediment-water interface greenhouse gas flux monitoring device according to claim 1, characterized in that, The exhaust structure includes a pull rod (10) and a piston (9). The piston (9) is installed inside the gas monitoring box (2). The piston (9) is connected to the pull rod (10). The pull rod (10) extends out of the gas monitoring box (2).

5. The sediment-water interface greenhouse gas flux monitoring device according to claim 4, characterized in that, The gas sampling structure is a gas bag, and a gas sampling hole (3) is provided on the side wall of the gas monitoring box (2). The gas bag is connected to the gas monitoring box (2) through the gas sampling hole (3).

6. The sediment-water interface greenhouse gas flux monitoring device according to claim 5, characterized in that, Oil is applied to the connection of the fixing plate (7), oil is applied to the hole through the pull rod (10) on the side wall of the gas and water monitoring box (1), and oil is applied to the gas sampling hole (3) on the side wall of the gas monitoring box (2).

7. A method for measuring greenhouse gas fluxes at the sediment-water interface, implemented using the sediment-water interface greenhouse gas flux monitoring device according to any one of claims 1 to 6, characterized in that, Includes the following steps: Adjust the length of the slide rail (6) according to the water depth, and install the gas-water monitoring box (1) and the gas monitoring box (2) on the slide rail (6) by means of the buckle (5); Slowly lower the entire device into the water. When the device is close to the bottom, manipulate the fixing device to vertically insert it into the sediment to secure the entire device. Atmospheric samples were collected from the water surface at the sampling site using the gas sampling structure, and the concentration of greenhouse gases was denoted as C0. When the bottom of the device coincides with the sediment-water interface, the gas-water collection begins and the start time T0 is recorded. The water gradually passes through the filter structure and enters the gas-water monitoring box (1). The gas generated by the sediment in the area covered by the gas monitoring box (2) passes through the filter structure and enters the three gas monitoring boxes (2) respectively. After the collection period is over, adjust the buckle (5) so that the gas-water monitoring box (1) and the gas monitoring box (2) can slide up and down on the slide rail (6). Pull the rope connected to the gas-water monitoring box (1) and the gas monitoring box (2) to remove a single gas-water monitoring box (1) or gas monitoring box (2). At sampling time T 2-1 T 2-2 and T 2-3 At that time, the three gas monitoring boxes (2) can be taken out in sequence, and the gas in the monitoring box can be pushed into the gas sampling structure through the exhaust structure; At the end of sampling T 2-3 Simultaneously remove the gas-water monitoring box (1), and use a pump to send the water sample in the box into the collection bottle to complete the entire sampling process; The concentrations of greenhouse gases C0 in the collected atmospheric samples and C in the three gas monitoring chambers (2) were determined using a laboratory gas chromatograph. 2-1 C 2-2 and C 2-3 ; Calculate the greenhouse gas diffusion flux F at the sediment-water interface in each of the three gas monitoring chambers (2). 2-1 F 2-2 and F 2-3 The calculation formula is as follows: ； ； ； In the formula, V is the volume of a single gas monitoring box (2); A is the bottom area of ​​a single gas monitoring box (2); C 2-1 , C 2-2 and C 2-3 The gas concentration difference before and after sample collection in the three gas monitoring boxes (2) is respectively, with the atmospheric concentration as the initial concentration C0; T 2-1 , T 2-2 and T 2-3 These represent the time intervals at which samples are collected from the three gas monitoring chambers (2); Take F 2-1 F 2-2 and F 2-3 The arithmetic mean can be used as the average greenhouse gas diffusion flux F2 at the sediment-water interface at this monitoring point, using the formula: ； Greenhouse gases in water samples collected in the gas-water monitoring box (1) were collected using the headspace balance method, and their concentrations were determined by gas chromatography. ； In the formula, C w Dissolved gas concentration in water sample; C1 is the gas concentration measured after headspace equilibrium; C0 is the atmospheric background concentration; V0 is the headspace air volume / L; V1 is the water sample volume used for headspace measurement / L; R is the universal gas constant; T is the water temperature / K; K0 is the gas solubility coefficient; A1, A2, and A3 are constants; The total greenhouse gas flux F1 entering the gas-water monitoring box (1) through both diffusion and bubbling at the bottom is calculated using the following formula: In the formula, V is the volume of the gas-water monitoring box (1); A is the bottom area of ​​the gas-water monitoring box (1); C w The concentration of dissolved gases in the water sample in the gas-water monitoring box (1); T 2-3 The time interval for collecting samples by the air-water monitoring box (1); Calculate the time-varying average bubbling flux F of greenhouse gases at the sediment-water interface at this location. 2-1泡 F 2-2泡 and F 2-3泡 and total average bubbling flux F 1泡 The formula is: ； ； ； 。

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