Device and method for simulating phosphorus circulation process of sediment under different turbidity conditions of estuary

Abstract

The invention discloses a device and method for simulating the phosphorus circulation process of sediments under different turbidity conditions of an estuary, and relates to the technical field of water resources and earth science, and the device for simulating the phosphorus circulation process of the sediments under the different turbidity conditions of the estuary comprises a water tank structure, a stirring structure and a multi-parameter water quality analyzer, a plurality of sampling ports are formed in the side wall of the water tank structure, the stirring structure can extend into the water tank structure, a probe structure of the multi-parameter water quality analyzer can extend into the water tank structure, and the probe structure is used for collecting water quality information. According to the device and the method for simulating the phosphorus circulation process of the sediments under different turbidity conditions of the estuary, real-time monitoring of data can be realized in a laboratory, and the accuracy is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of water resources and earth science, and in particular to a device and a method for simulating a sediment phosphorus cycle process under different turbidity conditions in an estuary. Background Art

[0002] As a key area of ​​land-sea interaction, the ecological and environmental health of estuaries has attracted much attention. In recent years, the intensification of human activities in the coastal areas has led to frequent estuarine eutrophication problems. Phosphorus, as a key limiting element of marine primary productivity, is generally considered to be the main factor causing estuarine eutrophication. In estuarine systems, phosphorus mainly exists in dissolved and particulate states, and constantly migrates and transforms between water and sediments. Suspended particles, as an important transfer medium between the two, can maintain the phosphorus concentration balance at the water-sediment interface. However, the hydrodynamics of the maximum turbidity zone in the estuary change dramatically, resulting in dynamic changes in the concentration of suspended particles in the water, which in turn affects the properties of the water-sediment interface (pH, dissolved oxygen, microbial activity) and the transformation and redistribution of phosphorus forms. In addition, the determination process of suspended particle concentration is complicated and cannot be monitored in real time, while turbidity and suspended particle concentration are closely related and can be converted to each other through conversion coefficients. Therefore, more in-depth research is needed on the impact of different turbidity conditions in estuaries on the migration and transformation of phosphorus.

[0003] Most of the experimental data in the studies come from intermittent field sampling, which makes it difficult to achieve real-time monitoring and accurate description of the phosphorus cycle process. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary, so as to solve the problems existing in the above-mentioned prior art, realize real-time monitoring of data in the laboratory, and ensure accuracy.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary, comprising a water tank structure, a stirring structure and a multi-parameter water quality analyzer. The side wall of the water tank structure is provided with a plurality of sampling ports, the stirring structure can extend into the water tank structure, the probe structure of the multi-parameter water quality analyzer can extend into the water tank structure, and the probe structure is used to collect water quality information.

[0007] Preferably, it also includes a high-resolution pore water sampling device and a thin film diffusion gradient device, and the high-resolution pore water sampling device and the thin film diffusion gradient device can extend into the water tank structure.

[0008] Preferably, the probe structure includes a turbidity probe, a dissolved oxygen probe, a salinity probe, a temperature probe and a pH probe.

[0009] Preferably, the stirring structure includes a motor, a coupling, a transmission rod and a propeller. The motor is located outside the water tank structure. The power output end of the motor is connected to one end of the transmission rod through a coupling. The transmission rod can extend into the water tank structure. The other end of the transmission rod is connected to the propeller in the water tank structure.

[0010] Preferably, the motor is arranged on the water tank structure via a bracket, and the bracket is made of organic glass.

[0011] Preferably, the transmission rod and the propeller are both made of corrosion-resistant materials.

[0012] Preferably, the water tank structure is made of plexiglass, and the water tank structure includes an upper flange, a water tank body and a lower flange. The upper flange is located at the upper end of the water tank body, the sampling port is located at the water tank body, and the lower flange is located at the lower end of the water tank body. The size of the lower flange is larger than that of the upper flange.

[0013] Preferably, the upper flange and the lower flange are respectively detachably connected to the water tank body, and water stop pads are provided between the upper flange and the water tank body and between the lower flange and the water tank body.

[0014] Preferably, a plurality of sampling ports are provided on the side wall of the water tank structure from top to bottom.

[0015] The present invention also provides a method for using the device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary, comprising the following steps:

[0016] Step 1: prepare several devices for simulating the phosphorus cycle process of sediments under different turbidity conditions in a constant temperature and light-proof room, add fresh sediment samples into the water tank structure, and then add in-situ seawater or artificial seawater with known phosphorus content;

[0017] Step 2: The water tank structure is left stationary, and the turbidity of the water in the water tank structure is measured with a probe structure. When the turbidity is less than 1, the water in the water tank structure is in a stationary state, and the water-sediment interface reaches an equilibrium state.

[0018] Step 3, according to the historical measured turbidity value of the maximum turbidity zone of the estuary, select several turbidity values ​​for experiment, wherein the device simulating the phosphorus cycle process of the sediment under different turbidity conditions in the estuary with a turbidity value of 0 is used as a blank control, the probe structure is extended into the water body, and the stirring structures of the devices simulating the phosphorus cycle process of the sediment under different turbidity conditions in the estuary are turned on, so that the turbidity value of the water body of each water tank structure is stabilized to the corresponding preset value, and the corresponding rotation speed of each stirring structure is recorded at this time, and then each water tank structure is left to stand to allow the suspended matter in the water tank structure to settle again until the turbidity measured by the probe structure is less than 1;

[0019] Step 4: Before the experiment begins, collect surface sediment samples and overlying water samples in each water tank structure, and add in-situ seawater or artificial seawater to the original height. One experimental cycle is divided into a suspension stage and a sedimentation stage. In the suspension stage, turn on the stirring structure and adjust the speed to the corresponding speed to make the water body of each water tank structure reach the preset turbidity condition. During this period, regularly observe the dissolved oxygen, salinity, water temperature and pH value in the overlying water, turn off the stirring structure, and let the water-sediment enter the sedimentation stage;

[0020] Step 5, repeat the above experimental cycle several times, the whole experimental process is divided into an early cultivation stage and a late cultivation stage, collect surface sediment samples and overlying water samples after the suspension stage of each cycle, and immediately replenish in-situ seawater or artificial seawater after each sampling, and insert the high-resolution pore water sampling device and the thin film diffusion gradient device into the sediment after the suspension stage of any experimental cycle in the early cultivation stage and the suspension stage of any experimental cycle in the late cultivation stage, and take them out after a period of time;

[0021] Step six: Determine the content of various forms of phosphorus, phosphatase activity and abundance of phosphorus cycle functional genes in the collected overlying water, pore water and sediment samples, and analyze and organize the data according to different turbidity conditions and time changes.

[0022] Compared with the prior art, the present invention has achieved the following technical effects:

[0023] The present invention adopts a stirring structure and combines it with a multi-parameter water quality analyzer to simulate different turbidity conditions in the maximum turbidity zone of the estuary, monitor its environmental changes in real time, improve the timeliness and accuracy of data acquisition, and make up for the shortcomings of traditional intermittent monitoring. At the same time, the device can collect water and sediment samples at different depths at any time for physical and chemical indicators and biological information analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic diagram of a device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to the present invention;

[0026] In the figure: 1: motor, 2: coupling, 3: upper flange; 4: water tank body, 5: transmission rod, 6: sampling port, 7: propeller, 8: lower flange, 9: bolts; 10: water stop pad; 11: multi-parameter water quality analyzer, 12: probe structure. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The purpose of the present invention is to provide a device and method for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary, so as to solve the problems existing in the above-mentioned prior art, realize real-time monitoring of data in the laboratory, and ensure accuracy.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Embodiment 1

[0031] like Figure 1 As shown, this embodiment provides a device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary, including a water tank structure, a stirring structure and a multi-parameter water quality analyzer 11. The side wall of the water tank structure is provided with a plurality of sampling ports 6 from top to bottom, the stirring structure can extend into the water tank structure, and the probe structure 12 of the multi-parameter water quality analyzer 11 (WTW) can extend into the water tank structure, and the probe structure 12 is used to collect water quality information. This device is mainly divided into two parts, a simulation culture device and a real-time monitoring device. The simulation culture device will be used to simulate different turbidity conditions and detect the water-sediment phosphorus cycle process, and the real-time monitoring device will be used to measure turbidity and monitor different environmental factors.

[0032] Specifically, the present embodiment further includes a high-resolution pore water sampling (HR-Peeper) device and a thin film diffusion gradient (DGT) device, and the high-resolution pore water sampling device and the thin film diffusion gradient device can be extended into the water tank structure.

[0033] In this embodiment, the probe structure 12 includes a turbidity probe, a dissolved oxygen probe, a salinity probe, a temperature probe and a pH probe. The turbidity probe is used to detect turbidity, the dissolved oxygen probe is used to detect dissolved oxygen concentration, the salinity probe is used to detect salinity, the temperature probe is used to detect temperature, and the pH probe is used to detect pH value. The multi-parameter water quality analyzer 11 can display real-time turbidity value, dissolved oxygen concentration, temperature and pH value, and record them to complete real-time monitoring of turbidity, dissolved oxygen concentration, temperature and pH.

[0034] In this embodiment, the stirring structure includes a motor 1, a coupling 2, a transmission rod 5 and a propeller 7. The motor 1 adopts an integrated variable frequency motor with a rated power of 25W and a maximum speed of 450r / min. The transmission rod 5 and the propeller 7 are both made of corrosion-resistant materials, preferably polytetrafluoroethylene. The frequency converter is used to control the speed of the motor 1, and the stepless speed regulation of the motor 1 can be realized. The motor 1 is located outside the water tank structure. The motor 1 is connected to one end of the transmission rod 5 through the coupling 2. The diameter of the transmission rod 5 is 8mm. The transmission rod 5 can be extended into the water tank structure. The other end of the transmission rod 5 is connected to the propeller 7 in the water tank structure, and the maximum expansion diameter of the propeller 7 is 80mm. The rotation of the propeller 7 driven by the motor 1 can change the water flow state in the water tank structure, change the shear stress of the overlying water-sediment interface, and by adjusting the connection position of the coupling 2 and the transmission rod 5, the height of the propeller 7 can be changed in a small range.

[0035] In this embodiment, the motor 1 is arranged on the water tank structure through a bracket, the bracket is made of organic glass, and the transmission rod 5 is rotatably connected with the bracket through a coupling 2. The bracket includes two arc-shaped, two square and two rectangular organic glass plates, the two arc-shaped organic glass plates are arranged oppositely, the two square organic glass plates are symmetrically arranged at the upper and lower ends of the two arc-shaped organic glass plates, and the two rectangular organic glass plates are symmetrically arranged, and the upper and lower ends of the two rectangular organic glass plates are respectively connected to the square organic glass plates.

[0036] In this embodiment, the water tank structure is made of organic glass, and the water tank structure includes an upper flange 3, a water tank body 4 and a lower flange 8. The upper flange 3 is located at the upper end of the water tank body 4. The upper flange 3 has a diameter of 220 mm and a thickness of 8 mm. The water tank body 4 is cylindrical, and the water tank body 4 is 400 mm high, 160 mm in inner diameter, and 5 mm in wall thickness. The probe structure 12 is located at a height of about 15 cm, and the sampling port 6 is located at the water tank body 4. The sampling port 6 is preferably six, and is 160 mm, 180 mm, 200 mm, 220 mm, and 270 mm away from the bottom of the water tank structure, respectively. m and 320mm, the diameter of the sampling port 6 is 6mm, a 2mm plexiglass tube is inserted into the sampling port 6 as a water intake hole, the end of the plexiglass tube is flush with the inner wall of the sink body 4, and a silicone hose with a diameter of 8mm is put on the plexiglass tube, and the switch is controlled by a water stop clamp. The lower flange 8 is located at the lower end of the sink body 4. The size of the lower flange 8 is larger than that of the upper flange 3. The lower flange 8 is square, with a side length of 300mm and a thickness of 16mm. The setting of the lower flange 8 overcomes the shaking and tilting caused by the high-speed rotation of the motor 1 and enhances the structural stability of the device.

[0037] In this embodiment, the upper flange 3 and the lower flange 8 are detachably connected to the sink body 4 via bolts 9 with a diameter of 9 mm, and water stop pads 10 are provided between the upper flange 3 and the sink body 4 and between the lower flange 8 and the sink body 4.

[0038] This embodiment uses an integrated variable frequency motor, combined with a multi-parameter water quality analyzer 11, which can simulate different turbidity conditions in the maximum turbidity zone of the estuary and monitor its environmental changes in real time. At the same time, the device can collect water and sediment samples at different depths at any time for physical and chemical indicators and biological information analysis. In conjunction with a high-resolution pore water sampling (HR-Peeper) device and a thin film diffusion gradient (DGT) device, it helps to monitor and analyze the migration and transformation rates of various forms of phosphorus during turbidity changes.

[0039] This embodiment can simulate different turbidity conditions and is applicable to estuaries, lakes, rivers and reservoirs of different hydrodynamic types; at the same time, the device is easy to install and has good airtightness, and the lower flange 8 and the base increase the bottom weight, avoiding the vibration caused by the high-speed rotation of the motor 1; and the device can collect overlying water samples of different depths as needed to observe the migration process of phosphorus at different depths; the device combines the water tank structure with the multi-parameter water quality analyzer 11 to achieve real-time monitoring of turbidity and basic physical and chemical properties during the cultivation process; and combined with a high-resolution pore water sampling (HR-Peeper) device and a thin film diffusion gradient (DGT) device, it can help to observe the adsorption / desorption process of phosphorus at the water-sediment interface without affecting the sediment morphology.

[0040] Embodiment 2

[0041] This embodiment provides a method for using the device of embodiment 1 to simulate the phosphorus cycle process of sediments under different turbidity conditions in an estuary, comprising the following steps:

[0042] Step 1: prepare several devices for simulating the phosphorus cycle process of sediments under different turbidity conditions in the estuary in a constant temperature and light-proof room, open the upper flange 3, add fresh sediment samples to the water tank structure to a distance of 10 cm from the bottom of the water tank structure, then add in-situ seawater or artificial seawater with a known phosphorus content to a water depth of about 28 cm, and fix the upper flange 3 to prevent subsequent high-speed rotation of the motor 1 from causing vibration;

[0043] Step 2: The water tank structure is left to stand. If there is no leakage in the water tank structure after 24 hours, it means that the water tank structure is well sealed. The probe structure 12 is used to measure the turbidity of about 10 cm underwater in the water tank structure. When the turbidity is less than 1, it can be judged that the water in the water tank structure is in a static state, and the water-sediment interface has reached a state of equilibrium, and the experiment can be further started.

[0044] Step three, according to the historical measured turbidity value of the maximum turbidity zone in the estuary, select several turbidity values ​​for experiment, for example, turbidity values ​​of 0, 50, 100 and 200 can be selected for experiment, wherein the device simulating the phosphorus cycle process of the sediment under different turbidity conditions in the estuary with a turbidity value of 0 is used as a blank control, the probe structure 12 is extended to 10 cm underwater, and the stirring structures of the devices simulating the phosphorus cycle process of the sediment under different turbidity conditions in the estuary are turned on, so that the turbidity value of the water body of each water tank structure is stabilized to the corresponding preset value, and the corresponding rotation speed of each stirring structure is recorded at this time, and then each water tank structure is left to stand to allow the suspended matter in the water tank structure to settle again until the turbidity measured by the probe structure 12 is less than 1;

[0045] Step 4, before the experiment begins, collect surface sediment samples (0-1 cm) and overlying water samples in each water tank structure (the detection positions of the overlying water samples are the surface, middle and bottom layers of the water body, respectively, corresponding to the sampling ports 6 of this embodiment, which are the first, third and sixth sampling ports 6 from top to bottom), and add in-situ seawater or artificial seawater to the original height. One experimental cycle is divided into a suspension stage and a sedimentation stage. One experimental cycle is 24 hours. In the suspension stage, turn on the stirring structure and adjust it to the corresponding speed so that the water body of each water tank structure reaches the preset turbidity condition and maintains it for 8 hours. During this period, regularly observe the dissolved oxygen, salinity, water temperature and pH value in the overlying water, turn off the stirring structure, and allow the water-sediment to enter the sedimentation stage for 16 hours;

[0046] Step 5, repeat the above experimental cycle several times, preferably nine times in this embodiment, the whole experimental process is divided into an early culture stage (the first to third experimental cycles) and a late culture stage (the fourth to ninth experimental cycles), collect surface sediment samples and overlying water samples after the suspension stage of each cycle, and immediately replenish in situ seawater or artificial seawater after each sampling, after the suspension stage of any experimental cycle in the early culture stage (for example, the first experimental cycle) and the suspension stage of any experimental cycle in the late culture stage (for example, the seventh experimental cycle), insert the high-resolution pore water sampling (HR-Peeper) device and the thin film diffusion gradient (DGT) device into the sediment, and ensure that the top heights of the handles of the two are consistent, take out the thin film diffusion gradient (DGT) device after 24 hours, and take out the high-resolution pore water sampling (HR-Peeper) device after 48 hours, and put them into a moist, light-proof aluminum foil sealed bag;

[0047] Step 6: Determine the content of various forms of phosphorus, phosphatase activity and abundance of phosphorus cycle functional genes in the collected overlying water, pore water and sediment samples, and analyze and organize the data according to different turbidity conditions and time changes. After the experiment, the cleaning device can be used repeatedly.

[0048] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary, characterized by: It includes a water tank structure, a stirring structure and a multi-parameter water quality analyzer. The side wall of the water tank structure is provided with a plurality of sampling ports. The stirring structure can extend into the water tank structure. The probe structure of the multi-parameter water quality analyzer can extend into the water tank structure. The probe structure is used to collect water quality information.

2. The device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to claim 1, characterized in that: It also includes a high-resolution pore water sampling device and a thin film diffusion gradient device, and the high-resolution pore water sampling device and the thin film diffusion gradient device can extend into the water tank structure.

3. The device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to claim 1, characterized in that: The probe structure comprises a turbidity probe, a dissolved oxygen probe, a salinity probe, a temperature probe and a pH probe.

4. The device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to claim 1, characterized in that: The stirring structure includes a motor, a coupling, a transmission rod and a propeller. The motor is located outside the water tank structure. The power output end of the motor is connected to one end of the transmission rod through a coupling. The transmission rod can extend into the water tank structure. The other end of the transmission rod is connected to the propeller in the water tank structure.

5. The device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to claim 4, characterized in that: The motor is arranged on the water tank structure through a bracket, and the bracket is made of organic glass.

6. The device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to claim 4, characterized in that: The transmission rod and the propeller are both made of corrosion-resistant materials.

7. The device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to claim 1, characterized in that: The water tank structure is made of organic glass, and includes an upper flange, a water tank body and a lower flange. The upper flange is located at the upper end of the water tank body, the sampling port is located at the water tank body, and the lower flange is located at the lower end of the water tank body. The size of the lower flange is larger than that of the upper flange.

8. The device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to claim 7, characterized in that: The upper flange and the lower flange are respectively connected to the water tank body in a detachable manner, and water stop pads are arranged between the upper flange and the water tank body and between the lower flange and the water tank body.

9. The device for simulating the phosphorus cycle process of sediments under different turbidity conditions in an estuary according to claim 1, characterized in that: The side wall of the water tank structure is provided with a plurality of sampling ports from top to bottom.

10. A method using the device for simulating the phosphorus cycle of sediments under different turbidity conditions in an estuary according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: prepare several devices for simulating the phosphorus cycle process of sediments under different turbidity conditions in a constant temperature and light-proof room, add fresh sediment samples into the water tank structure, and then add in-situ seawater or artificial seawater with known phosphorus content; Step 2: The water tank structure is left stationary, and the turbidity of the water in the water tank structure is measured with a probe structure. When the turbidity is less than 1, the water in the water tank structure is in a stationary state, and the water-sediment interface reaches an equilibrium state. Step 3, according to the historical measured turbidity value of the maximum turbidity zone of the estuary, select several turbidity values ​​for experiment, wherein the device simulating the phosphorus cycle process of the sediment under different turbidity conditions in the estuary with a turbidity value of 0 is used as a blank control, the probe structure is extended into the water body, and the stirring structures of the devices simulating the phosphorus cycle process of the sediment under different turbidity conditions in the estuary are turned on, so that the turbidity value of the water body of each water tank structure is stabilized to the corresponding preset value, and the corresponding rotation speed of each stirring structure is recorded at this time, and then each water tank structure is left to stand to allow the suspended matter in the water tank structure to settle again until the turbidity measured by the probe structure is less than 1; Step 4: Before the experiment begins, collect surface sediment samples and overlying water samples in each water tank structure, and add in-situ seawater or artificial seawater to the original height. One experimental cycle is divided into a suspension stage and a sedimentation stage. In the suspension stage, turn on the stirring structure and adjust the speed to the corresponding speed to make the water body of each water tank structure reach the preset turbidity condition. During this period, regularly observe the dissolved oxygen, salinity, water temperature and pH value in the overlying water, turn off the stirring structure, and let the water-sediment enter the sedimentation stage; Step 5, repeat the above experimental cycle several times, the whole experimental process is divided into an early cultivation stage and a late cultivation stage, collect surface sediment samples and overlying water samples after the suspension stage of each cycle, and immediately replenish in-situ seawater or artificial seawater after each sampling, and insert the high-resolution pore water sampling device and the thin film diffusion gradient device into the sediment after the suspension stage of any experimental cycle in the early cultivation stage and the suspension stage of any experimental cycle in the late cultivation stage, and take them out after a period of time; Step six: Determine the content of various forms of phosphorus, phosphatase activity and abundance of phosphorus cycle functional genes in the collected overlying water, pore water and sediment samples, and analyze and organize the data according to different turbidity conditions and time changes.

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