Device for in-situ suspended sediment denitrification rate experiment in estuary area under tidal action

Abstract

The present invention discloses a device for an in-situ suspended sediment denitrification rate experiment in water bodies under the action of tides in estuaries, comprising an incubator, a float and a nitrate nitrogen isotope injector, wherein the incubator is fixedly connected to the bottom of the float, a water inlet and a water inlet switch matched with the water inlet are arranged at the upper end of the incubator, a sampling tube is also airtightly connected to the incubator, a water stop valve is arranged on the sampling tube, an agitator is arranged in the incubator, and the injection port of the nitrate nitrogen isotope injector is arranged inside the incubator. Compared with the prior art, the device solves the current difficulty in carrying out the suspended sediment denitrification rate experiment in in-situ water bodies under the action of tides in estuaries, and has high practical value and broad promotion prospects for understanding and mastering the nitrogen balance process and eutrophication trend under the action of tides in estuaries.

Description

Technical Field

[0001] The invention relates to a device for in-situ experiment of suspended sediment denitrification rate in water body, in particular to a device for in-situ experiment of suspended sediment denitrification rate in water body under tidal action in estuary area. Background Art

[0002] The estuary is an important transition zone and connection section between inland rivers and the ocean. Nitrogen pollution in the upper reaches of the estuary is one of the main factors leading to eutrophication and red tide in the estuary. Suspended sediment in the water body is an important carrier for the attachment of denitrifying microorganisms, playing an important role in reducing excessive nitrogen pollution in the estuary water body and regulating the nitrogen balance between land and sea. Studies have shown that the maximum denitrification rate of suspended sediment in the Yangtze River Estuary can reach 20.83 μmol NL -1 d -1 , that is, it can effectively reduce the input of active nitrogen into the basin.

[0003] However, due to the rapid changes in tides and fluctuations in physical and chemical environmental indicators in estuaries, there is currently a lack of effective in-situ observation methods for the denitrification of suspended sediment under the action of tides in estuaries, and the method of taking samples out in the field and then taking them back to the laboratory for measurement is usually adopted. The changes in the physical and chemical environment of in-situ and indoor experiments often make it difficult to accurately quantify the denitrification contribution of suspended sediment in the water body in the actual nitrogen balance measurement. At the same time, it is difficult to effectively distinguish the main physical and chemical factors that affect denitrification in the complex hydrological and physical and chemical environment of the estuary area, and it is impossible to provide effective support for in-depth research on the denitrification mechanism of suspended sediment in the estuary area. Summary of the invention

[0004] In view of the problems in the above-mentioned prior art, the present invention designs a device for in-situ suspended sediment denitrification rate experiment of water body under the action of tide in estuary area, which is helpful to scientifically measure the denitrification contribution of suspended sediment in estuary area under the action of tide and scientifically evaluate the land-sea nitrogen balance flux, provide in-situ data support for in-depth research on the influence mechanism of suspended sediment denitrification in water body in estuary area, and further provide a scientific basis for nitrogen control in estuary area, and solve the current problem of difficulty in carrying out in-situ measurement of suspended sediment denitrification rate in water body under the action of tide in estuary area.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A device for in-situ suspended sediment denitrification rate experiment in estuary area under tidal action, comprising an in-situ culture unit,

[0007] The in-situ culture experimental unit comprises an incubator 3, a float 20 and a nitrate isotope injector 18. The incubator 3 is fixedly connected to the bottom of the float 20.

[0008] The incubator 3 is provided with a water inlet 12 and a water inlet switch 13 matched with the water inlet 12 at the upper end. The incubator 3 is also airtightly connected with a sampling tube 15, and the sampling tube 15 is provided with a water stop valve 16.

[0009] The incubator 3 is provided with a stirrer 4.

[0010] The injection port 14 of the nitrate nitrogen isotope injector 18 is disposed inside the incubator 3 .

[0011] Further, the incubator 3 is a cube, and a bottom plate sealing ring 6 is arranged around the bottom plate 7 of the cube, the bottom plate 7 is slidably connected to the side of the cube, and the sampling tube 15 is arranged on the top of the incubator 3. The slidable bottom plate 7 cooperates with the bottom plate sealing ring 6, and can realize non-interference sampling by moving the bottom plate 7 upward after the cultivation is completed, avoiding contamination of the sample caused by the sampling process, and completing the sample collection work.

[0012] Furthermore, a bottom plate pushing handle 5 is provided below the bottom plate 7. After the experiment is completed, the bottom plate 7 can be pushed by pushing the bottom pushing handle 5 to facilitate pushing the bottom plate 7.

[0013] Furthermore, the incubator 3 is fixedly connected to the float 20 via a connecting rod 2 .

[0014] Furthermore, the device for in-situ suspended sediment denitrification rate experiment in estuary area under tidal action also includes a signal collection system, a control system and a power supply 23.

[0015] The signal collection system includes a signal transmitter 22 arranged above the water surface, an external turbidity probe 8 arranged outside the incubator 3, and an internal turbidity probe 11, an internal temperature probe 10 and an internal dissolved oxygen probe 9 arranged inside the incubator 3. The external turbidity probe 8, the internal turbidity probe 11, the internal temperature probe 10 and the internal dissolved oxygen probe 9 are connected to the control system through the signal transmitter 22.

[0016] The stirrer 4 is in communication connection with the control system.

[0017] The power source 23 is disposed above the water surface, and the power source 23 is connected to the signal collection system and the stirrer 4 .

[0018] The signal transmitter 22 is used to send the physical and chemical index information in the incubator 3, the power supply 23 is used to provide the signal collection system and the electric energy required by the agitator 4, and the internal turbidity probe 11, the internal temperature probe 10, and the internal dissolved oxygen probe 9 can monitor the dynamic change characteristics of the turbidity, temperature and dissolved oxygen in the incubator 3 in real time, and feed the signal back to the control system. On the other hand, the external turbidity probe can monitor the turbidity change characteristics in the external water body in real time and feed the signal back to the control system, and the control system corrects the rotation speed of the agitator 4 in real time to achieve basically consistent suspended sand concentration inside and outside.

[0019] Furthermore, the device for the in-situ suspended sediment denitrification rate experiment of water body under the action of tide in estuary area further comprises a pusher 1, the pusher 1 is fixedly connected to the float 20 and arranged below the water surface, the pusher is in communication connection with the control system and is powered by the power supply 23. The pusher 1 is used to push the device to the designated water area.

[0020] Furthermore, the stirrer 4 is a speed-adjustable magnetic stirrer, which drives the suspended sand in the incubator to re-suspend by adjusting the rotation speed, thereby simulating the in-situ suspended sand concentration under different tidal forces.

[0021] Furthermore, the water inlet switch 13 includes a water inlet cover 125 that cooperates with the water inlet 12, a switch push rod 124 fixedly connected to the water inlet cover 125, a switch transmission device and a switch transmission motor 121. The switch transmission motor controls the movement of the water inlet cover by pushing and pulling the switch push rod 124 through the switch transmission device to achieve the closing or opening of the water inlet. The switch transmission motor 121 is communicated with the control system and is powered by the power supply 23.

[0022] The switch transmission device includes a switch transmission gear 122 and a switch rotating screw 123. The switch rotating screw is connected to the switch push rod through threads. The switch transmission gear 122 is connected to the switch transmission motor and the switch rotating screw respectively.

[0023] Furthermore, the nitrate nitrogen isotope injector 18 includes an injection port 14 and an injection pushing device respectively arranged at both ends of a syringe 185, the injection pushing device includes a rubber plug 184, an injection pushing rod 183, an injection transmission device and an injection transmission motor 186, the rubber plug 184 is arranged in the syringe 185 and is movably connected to the syringe 185, the rubber plug 184 is fixedly connected to the injection pushing rod, the injection transmission motor controls the movement of the rubber plug 184 by pushing and pulling the injection pushing rod 183 through the injection transmission device, so as to realize the forward or backward movement of the rubber plug 184 relative to the injection port 14, and the injection transmission motor 186 is communicatively connected to the control system and is powered by the power supply 23.

[0024] The injection transmission device includes an injection transmission gear 181 and an injection rotating screw 182. The injection rotating screw is connected to the injection push rod through threads, and the injection transmission gear 181 is connected to the injection transmission motor and the injection rotating screw respectively.

[0025] Furthermore, the nitrate nitrogen isotope injector 18 contains nitrate nitrogen isotopes of standard concentration.

[0026] Furthermore, the control system includes a built-in computer and a signal transceiver 29 connected to the built-in computer, a display screen 24, a direction control button 25, a water quality standard selection button 26, a data transmission line 27 and a data transmission interface 28.

[0027] During the experiment, the in-situ experimental device can lower the in-situ culture experimental unit to the water surface of the estuary bank according to the needs of the in-situ suspended sand denitrification rate determination on site, manually or through the control system remote control pusher 1, send the in-situ culture experimental unit to the designated water area, open the water inlet switch 13 at the upper end of the incubator 3, wait for the in-situ water sample containing suspended sand to fill the incubator 3, then close the water inlet switch 13, open the nitrate nitrogen isotope automatic injector, and inject the standard concentration of nitrate nitrogen isotope into the incubator. At this time, the adjustable speed magnetic stirrer is started synchronously, and the dynamic change characteristics of turbidity, temperature and dissolved oxygen in the incubator are monitored through the internal turbidity probe, the internal temperature probe, and the internal dissolved oxygen probe. The turbidity change characteristics in the external water body are monitored in real time through the external turbidity probe, which is used to correct the speed of the adjustable speed magnetic stirrer in real time to achieve basically consistent suspended sand concentration inside and outside. The functional microorganisms attached to the suspended sand in the culture room use nitrate nitrogen to carry out denitrification reaction. After reacting for 24 hours under the in-situ physical and chemical environmental conditions, nitrogen gas is finally produced and dissolved in the water body of the incubator. After the in-situ culture experiment is completed, the in-situ culture unit is remotely controlled to return to the shore through the remote control terminal. By pushing the handle on the bottom plate and opening the water stop valve, the supernatant culture solution after culture is filled into the vacuum tube in turn, and a ZnCl2 solution with a mass concentration of 50% is injected into the vacuum tube 17 to terminate the experiment. The vacuum tube sample is taken to the gas phase laboratory to detect the nitrogen concentration value in the water body at the initial and end times (the water sample at the initial time is manually collected on site), and finally the nitrogen concentration difference before and after the culture is calculated, and then the denitrification rate of the in-situ suspended sand is calculated. This device has strong applicability, a high degree of automation, and relatively simple operation. It can realize the in-situ determination of the denitrification rate of suspended sand under the action of tides in the estuary area, avoiding the adverse effects caused by the changes in the physical and chemical environment during the previous sampling process back to the laboratory. It provides an in-situ monitoring method for understanding and mastering the denitrification contribution of suspended sand in the water body under the action of tides in the estuary area, and has a relatively broad practical value and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0029] Figure 1 It is a structural schematic diagram of the in-situ culture experimental unit of the device for in-situ water body suspended sediment denitrification rate experiment under the action of tides in estuary area in Example 1 of the present invention.

[0030] Figure 2 It is a structural schematic diagram of the water inlet switch of the device used for the in-situ suspended sediment denitrification rate experiment of the water body under the action of tide in the estuary area in Example 1 of the present invention.

[0031] Figure 3 It is a schematic diagram of the structure of the nitrate nitrogen isotope injector of the device used for the in-situ suspended sediment denitrification rate experiment of water body under the action of tide in estuary area in Example 1 of the present invention.

[0032] Figure 4 It is a schematic diagram of the control system of the device used for the in-situ suspended sediment denitrification rate experiment of the estuary area under the action of tides in Example 1 of the present invention.

[0033] In the figure: 1 is a pusher, 2 is a connecting rod, 3 is an incubator, 4 is a stirrer, 5 is a bottom plate push handle, 6 is a bottom plate sealing ring, 7 is a bottom plate, 8 is an external turbidity probe, 9 is an internal dissolved oxygen probe, 10 is an internal temperature probe, 11 is an internal turbidity probe, 12 is a water inlet, 13 is a water inlet switch, 14 is an injection port, 15 is a sampling tube, 16 is a water stop valve, 17 is a vacuum tube, 18 is a nitrate nitrogen isotope injector, 19 is an electric wire, 20 is a float, 21 is an electric wire, 22 is a signal transmitter, 23 is the power supply, 24 is the display screen, 25 is the direction control button, 26 is the water quality index selection button, 27 is the data transmission line, 28 is the data transmission interface, 29 is the signal transceiver, 121 is the switch drive motor, 122 is the open drive gear, 123 is the switch rotating screw, 124 is the switch push rod, 125 is the water inlet cover, 181 is the injection drive gear, 182 is the injection rotating screw, 183 is the injection push rod, 184 is the rubber plug, 185 is the injection barrel, and 186 is the injection drive motor. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. Example 1

[0035] refer to Figure 1~Figure 4The device shown is used for an in-situ suspended sediment denitrification rate experiment of an estuarine water body under the action of tides, and includes an in-situ culture unit. The in-situ culture experimental unit includes a culture box 3, a float 20 and a nitrate nitrogen isotope injector 18. The culture box 3 is fixedly connected to the bottom of the float 20. The upper end of the culture box 3 is provided with a water inlet 12 and a water inlet switch 13 cooperating with the water inlet 12. The culture box 3 is also sealed with a sampling tube 15, and the sampling tube 15 is provided with a water stop valve 16. The culture box 3 is provided with a stirrer 4, and the injection port 14 of the nitrate nitrogen isotope injector 18 is provided inside the culture box 3.

[0036] The incubator 3 is a cube, and a bottom plate sealing ring 6 is arranged around the bottom plate 7 of the cube. The bottom plate 7 is slidably connected to the side of the cube, and the sampling tube 15 is arranged on the top of the incubator 3. The slidable bottom plate 7 cooperates with the bottom plate sealing ring 6, so that non-interference sampling can be achieved by moving the bottom plate 7 upward after the incubation is completed, avoiding contamination of the sample caused by the sampling process, and completing the sample collection work.

[0037] A bottom plate pushing handle 5 is provided below the bottom plate 7. After the experiment is completed, the bottom plate 7 can be pushed by pushing the bottom pushing handle 5 to facilitate pushing the bottom plate 7.

[0038] The incubator 3 is fixedly connected to the float 20 via a connecting rod 2 .

[0039] The device for the in-situ suspended sediment denitrification rate experiment of water body under the action of tide in estuary area also includes a signal collection system, a control system and a power supply 23. The signal collection system includes a signal transmitter 22 arranged above the water surface, an external turbidity probe 8 arranged outside the incubator 3, and an internal turbidity probe 11, an internal temperature probe 10 and an internal dissolved oxygen probe 9 arranged inside the incubator 3. The external turbidity probe 8, the internal turbidity probe 11, the internal temperature probe 10 and the internal dissolved oxygen probe 9 are communicatively connected with the control system through the signal transmitter 22, and the agitator 4 is communicatively connected with the control system. The power supply 23 is arranged above the water surface, and the power supply 23 is connected with the signal collection system and the agitator 4.

[0040] The signal transmitter 22 is used to send the physical and chemical index information in the incubator 3, the power supply 23 is used to provide the signal collection system and the electric energy required by the agitator 4, and the internal turbidity probe 11, the internal temperature probe 10, and the internal dissolved oxygen probe 9 can monitor the dynamic change characteristics of the turbidity, temperature and dissolved oxygen in the incubator 3 in real time, and feed the signal back to the control system. On the other hand, the external turbidity probe can monitor the turbidity change characteristics in the external water body in real time and feed the signal back to the control system, and the control system corrects the rotation speed of the agitator 4 in real time to achieve basically consistent suspended sand concentration inside and outside.

[0041] The device for the in-situ suspended sediment denitrification rate experiment of the estuary area under the action of tides also includes a pusher 1, which is fixedly connected to the float 20 and arranged below the water surface, and is connected to the control system in communication and powered by the power supply 23. The pusher 1 is used to push the device to the designated water area.

[0042] The stirrer 4 is a speed-adjustable magnetic stirrer, which drives the suspended sand in the incubator to re-suspend by adjusting the rotation speed, thereby simulating the original suspended sand concentration under different tidal forces.

[0043] The water inlet switch 13 includes a water inlet cover 125 that cooperates with the water inlet 12, a switch push rod 124 fixedly connected to the water inlet cover 125, a switch transmission device and a switch transmission motor 121. The switch transmission motor controls the movement of the water inlet cover by pushing and pulling the switch push rod 124 through the switch transmission device to achieve the closing or opening of the water inlet. The switch transmission motor 121 is communicated with the control system and is powered by the power supply 23.

[0044] The switch transmission device includes a switch transmission gear 122 and a switch rotating screw 123. The switch rotating screw is connected to the switch push rod through threads. The switch transmission gear 122 is connected to the switch transmission motor and the switch rotating screw respectively.

[0045] The nitrate nitrogen isotope injector 18 includes an injection port 14 and an injection pushing device respectively arranged at both ends of a syringe 185, the injection pushing device includes a rubber plug 184, an injection pushing rod 183, an injection transmission device and an injection transmission motor 186, the rubber plug 184 is arranged in the syringe 185 and is movably connected to the syringe 185, the rubber plug 184 is fixedly connected to the injection pushing rod, the injection transmission motor controls the movement of the rubber plug 184 by pushing and pulling the injection pushing rod 183 through the injection transmission device, so as to realize the forward or backward movement of the rubber plug 184 relative to the injection port 14, the injection transmission motor 186 is communicated with the control system, and is powered by the power supply 23.

[0046] The injection transmission device includes an injection transmission gear 181 and an injection rotating screw 182. The injection rotating screw is connected to the injection push rod through threads, and the injection transmission gear 181 is connected to the injection transmission motor and the injection rotating screw respectively.

[0047] The nitrate nitrogen isotope injector 18 is filled with nitrate nitrogen isotopes of standard concentration.

[0048] The control system includes a built-in computer and a signal transceiver 29 connected to the built-in computer, a display screen 24 , a direction control button 25 , a water quality standard selection button 26 , a data transmission line 27 and a data transmission interface 28 .

[0049] Working process:

[0050] When it is necessary to measure the denitrification rate of suspended sediment in the in-situ water body of the estuary area, the first step is that the operator selects the measurement water area and makes preparations before the experiment, including filling the nitrate nitrogen isotope injector 18 with the configured standard concentration nitrate nitrogen isotope solution, closing the water stop valve 16, and checking the power supply and signal transmission status of the in-situ culture experimental unit; the second step is that the operator lowers the in-situ culture experimental unit to the surface of the designated water area in the estuary area, and remotely controls the pusher 1 through the control system to push the in-situ culture experimental unit to the experimental position of the designated water area; the third step is that the operator remotely controls the water inlet switch 13 through the control system to open it, and after the incubator 3 is filled with sandy water, the water inlet switch 13 is closed to achieve an overall closed environment for the incubator 3; the fourth step is that after the water inlet switch 13 is closed, the nitrate nitrogen isotope injector 18 is started to inject the standard concentration nitrate nitrogen isotope solution into the incubator 3; the fifth step is that the inner The turbidity probe 11, the internal temperature probe 10, the internal dissolved oxygen probe 9 and the external turbidity probe 8 detect the turbidity index in the water body inside and outside the incubator in real time, transmit the signal to the control system, and the control system remotely controls the rotation speed of the stirrer 4 accordingly, so that the turbidity inside and outside the incubator is basically consistent; Step 6, after the incubation stage is over, the operator remotely controls the pusher 1 to push the in-situ incubation experimental unit back to the shore; Step 7, the operator opens the water stop valve 16, and pushes the bottom plate push handle 5 to load the supernatant culture liquid after the reaction into the vacuum tube 17 (three parallel samples); Step 8, the operator injects a ZnCl2 solution with a mass concentration of 50% into the vacuum tube 17 to terminate the microbial reaction in the culture bottle; Step 9, the operator can take the three parallel samples of the on-site in-situ experimental reaction and the termination of the reaction back to the laboratory for testing, and then determine the denitrification rate of suspended sediment in the in-situ water body of the estuary area.

[0051] In general, this device has a high level of automation, a modular assembly structure, and a wider range of application scenarios. It solves the problem of insufficient representativeness of measurement data caused by changes in the physical and chemical environment after suspended sand and water samples are brought back from the site, and is easier to operate in situ and promote application.

[0052] The above description is only a specific implementation of the present invention, and the protection scope of the present invention is not limited thereto. Any simple transformation or replacement made by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the present application will not be limited to the specific embodiments described herein, but can cover the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A device for in-situ suspended sediment denitrification rate experiment in estuary area under tidal action, characterized in that: Including in situ culture unit, The in-situ culture unit comprises a culture box (3), a float (20) and a nitrate nitrogen isotope injector (18), wherein the culture box (3) is fixedly connected below the float (20). The incubator (3) is provided with a water inlet (12) and a water inlet switch (13) cooperating with the water inlet (12) at the upper end thereof. The incubator (3) is also airtightly connected with a sampling tube (15), and the sampling tube (15) is provided with a water stop valve (16). The incubator (3) is provided with a stirrer (4). The injection port (14) of the nitrate nitrogen isotope injector (18) is arranged inside the incubator (3); The device for in-situ suspended sediment denitrification rate experiment in estuary area under tidal action also includes a signal collection system, a control system and a power supply (23). The signal collection system comprises a signal transmitter (22) arranged above the water surface, an external turbidity probe (8) arranged outside the incubator (3), and an internal turbidity probe (11), an internal temperature probe (10) and an internal dissolved oxygen probe (9) arranged inside the incubator (3); the external turbidity probe (8), the internal turbidity probe (11), the internal temperature probe (10) and the internal dissolved oxygen probe (9) are connected to the control system for communication via the signal transmitter (22). The stirrer (4) is in communication connection with the control system, The power source (23) is arranged above the water surface, and the power source (23) is connected to the signal collection system and the stirrer (4).

2. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 1 is characterized in that: The incubator (3) is a cube, a bottom plate sealing ring (6) is arranged around the bottom plate (7) of the cube, the bottom plate (7) is slidably connected to the side of the cube, and the sampling tube (15) is arranged on the top of the incubator (3).

3. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 2 is characterized in that: A bottom plate pushing handle (5) is provided below the bottom plate (7).

4. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 1 is characterized in that: The incubator (3) and the float (20) are fixedly connected via a connecting rod (2).

5. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 1 is characterized in that: The stirrer (4) is a speed-adjustable magnetic stirrer.

6. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 1 is characterized in that: The nitrate nitrogen isotope injector (18) contains nitrate nitrogen isotopes of standard concentration.

7. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 1 is characterized in that: The device for in-situ suspended sediment denitrification rate experiment in estuary areas under tidal action also includes a pusher (1), the pusher (1) is fixedly connected to the float (20) and is arranged below the water surface, the pusher is communicatively connected to the control system, and is powered by the power supply (23).

8. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 1 is characterized in that: The water inlet switch (13) comprises a water inlet cover (125) matched with the water inlet (12), a switch push rod (124) fixedly connected to the water inlet cover (125), a switch transmission device and a switch transmission motor (121); the switch transmission motor controls the movement of the water inlet cover by pushing and pulling the switch push rod (124) through the switch transmission device, thereby closing or opening the water inlet; the switch transmission motor (121) is in communication connection with the control system and is powered by the power supply (23).

9. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 8, characterized in that: The switch transmission device comprises a switch transmission gear (122) and a switch rotating screw (123), the switch rotating screw being connected to the switch push rod via a thread, and the switch transmission gear (122) being connected to the switch transmission motor and the switch rotating screw respectively.

10. The device for in-situ suspended sediment denitrification rate experiment in estuary area under tidal action according to claim 1, characterized in that: The nitrate nitrogen isotope injector (18) comprises an injection port (14) and an injection push device respectively arranged at two ends of an injection barrel (185); the injection push device comprises a rubber plug (184), an injection push rod (183), an injection transmission device and an injection transmission motor (186); the rubber plug (184) is arranged in the injection barrel (185) and is movably connected to the injection barrel (185); the rubber plug (184) is fixedly connected to the injection push rod; the injection transmission motor controls the movement of the rubber plug (184) by pushing and pulling the injection push rod (183) through the injection transmission device, thereby realizing the advancement or retreat of the rubber plug (184) relative to the injection port (14); the injection transmission motor (186) is connected to the control system for communication and is powered by the power supply (23).

11. The device for in-situ suspended sediment denitrification rate experiment of estuarine water body under tidal action according to claim 10, characterized in that: The injection transmission device comprises an injection transmission gear (181) and an injection rotating screw (182), the injection rotating screw being connected to the injection push rod via a thread, and the injection transmission gear (181) being connected to the injection transmission motor and the injection rotating screw respectively.

12. The device for in-situ suspended sediment denitrification rate experiment in estuary area under tidal action according to claim 1, characterized in that: The control system comprises a built-in computer and a signal transceiver (29) connected to the built-in computer, a display screen (24), a direction control button (25), a water quality standard selection button (26), a data transmission line (27) and a data transmission interface (28).

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