Device and method for simulating phosphorus cycling process in sediments under different turbidity conditions in estuaries

Abstract

The present invention discloses a device and method for simulating the phosphorus cycle in sediments under varying turbidity conditions at an estuary. The device relates to the fields of water resources and earth science technology. The device comprises a water tank structure, a stirring structure, and a multi-parameter water quality analyzer. The sidewall 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. The device and method for simulating the phosphorus cycle in sediments under varying turbidity conditions at an estuary can achieve real-time data monitoring in a laboratory, ensuring accuracy.

Description

Technical Field

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

[0002] As key areas of land-sea interaction, the ecological and environmental health of estuaries has attracted considerable attention. In recent years, intensified human activities near coastal areas have led to frequent estuarine eutrophication. Phosphorus, a key limiting element for marine primary productivity, is generally considered the primary factor contributing to estuarine eutrophication. In estuarine systems, phosphorus exists primarily in dissolved and particulate forms, constantly migrating and transforming between water and sediment. Suspended particulate matter, a crucial transport medium between the two, maintains the phosphorus concentration balance at the water-sediment interface. However, the turbidity maximum zone in estuaries experiences dramatic hydrodynamic fluctuations, leading to dynamic changes in suspended particulate concentrations, which in turn influence the water-sediment interface properties (pH, dissolved oxygen, and microbial activity) and the transformation and redistribution of phosphorus forms. Furthermore, the measurement of suspended particulate matter concentration is complex and cannot be monitored in real time. However, turbidity and suspended particulate matter concentrations are closely correlated and can be converted to each other using a conversion factor. Therefore, further research is needed to investigate the impact of varying turbidity conditions on phosphorus migration and transformation in estuaries.

[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 and realize real-time monitoring of data in the laboratory to 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 circulation process of sediments under different turbidity conditions in an estuary. The device comprises a water tank structure, a stirring structure and a multi-parameter water quality analyzer. A plurality of sampling ports are provided on the side wall of the water tank structure. The stirring structure can be inserted into the water tank structure. The probe structure of the multi-parameter water quality analyzer can be inserted into the water tank structure. The probe structure is used to collect water quality information.

[0007] Preferably, it further comprises 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 be extended 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 organic glass, 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 a water-stop pad is 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 to simulate the phosphorus cycling process of sediments in estuaries under different turbidity conditions in a constant temperature and light-proof room. Add fresh sediment samples to the flume structure, and then add in situ seawater or artificial seawater with known phosphorus content.

[0017] Step 2: The water tank structure is allowed to stand still, and the turbidity of the water in the water tank structure is measured using the 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: Based on the historical measured turbidity values of the maximum turbidity zone in the estuary, several turbidity values are selected for the experiment, wherein a device simulating the phosphorus cycling process in 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 inserted into the water body, and the stirring structure of each device simulating the phosphorus cycling process in the sediment under different turbidity conditions in the estuary is turned on to stabilize the turbidity value of the water body in each water tank structure to a corresponding preset value. The rotation speed corresponding to each stirring structure at this time is recorded, and then each water tank structure is allowed 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, surface sediment samples and overlying water samples are collected from each flume structure, and in-situ seawater or artificial seawater is replenished to the original height. One experimental cycle is divided into a suspension phase and a settling phase. During the suspension phase, the stirring structure is turned on and adjusted to the corresponding speed to make the water in each flume structure reach the preset turbidity conditions. During this period, the dissolved oxygen, salinity, water temperature and pH value of the overlying water are regularly observed. The stirring structure is turned off to allow the water-sediment to enter the settling phase.

[0020] Step 5: Repeat the above experimental cycle several times. The entire experimental process is divided into an early incubation stage and a late incubation stage. After the suspension stage of each cycle, surface sediment samples and overlying water samples are collected. In situ seawater or artificial seawater is immediately replenished after each sampling. After the suspension stage of any experimental cycle in the early incubation stage and any experimental cycle in the late incubation stage, the high-resolution pore water sampling device and the thin film diffusion gradient device are inserted into the sediment and removed 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 and monitor its environmental changes in real time, thereby improving the timeliness and accuracy of data acquisition and making 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 index 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 following briefly introduces the drawings required for use in the embodiments. 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 any creative work.

[0025] Figure 1 Schematic diagram of the device for simulating the phosphorus cycle process in 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: bolt; 10: water stop pad; 11: multi-parameter water quality analyzer, 12: probe structure. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts 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 and realize real-time monitoring of data in the laboratory to 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] Example 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 estuaries, 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. The probe structure 12 of the multi-parameter water quality analyzer 11 (WTW) can extend into the water tank structure. 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, this 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. The multi-parameter water quality analyzer 11 can display and record real-time turbidity values, dissolved oxygen concentration, temperature, and pH values, completing real-time monitoring of turbidity, dissolved oxygen concentration, temperature, and pH.

[0034] In this embodiment, the stirring mechanism includes a motor 1, a coupling 2, a transmission rod 5, and a propeller 7. The motor 1 is an integrated variable-frequency motor with a rated power of 25W and a maximum speed of 450 r / min. The transmission rod 5 and propeller 7 are both made of corrosion-resistant materials, preferably polytetrafluoroethylene. A frequency converter is used to control the speed of the motor 1, enabling stepless speed regulation of the motor 1. The motor 1 is located outside the water tank structure. The motor 1 is connected to one end of the transmission rod 5 via the coupling 2. The transmission rod 5 has a diameter of 8mm and can extend into the water tank structure. The other end of the transmission rod 5 is connected to the propeller 7 in the water tank structure. The maximum expanded 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 and the shear stress at the overlying water-sediment interface. The height of the propeller 7 can be varied within a small range by adjusting the connection position of the coupling 2 and the transmission rod 5.

[0035] In this embodiment, the motor 1 is mounted on the water tank structure via a bracket made of organic glass. The transmission rod 5 is rotatably connected to the bracket via a coupling 2. The bracket comprises two arc-shaped, two square, and two rectangular organic glass panels. The two arc-shaped organic glass panels are positioned opposite each other, the two square organic glass panels are symmetrically positioned above and below the two arc-shaped organic glass panels, and the two rectangular organic glass panels are symmetrically positioned, with the upper and lower ends of the two rectangular organic glass panels respectively connected to the square organic glass panels.

[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, and 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, an inner diameter of 160 mm, and a wall thickness of 5 mm. The probe structure 12 is located at a height of about 15 cm, and the sampling port 6 is located in the water tank body 4. The sampling port 6 is preferably six, and is respectively 160 mm, 180 mm, 200 mm, 220 mm, and 270 mm away from the bottom of the water tank structure. m and 320mm, the diameter of the sampling port 6 is 6mm, a 2mm organic glass tube is inserted into the sampling port 6 as a water intake hole, the end of the organic glass tube is flush with the inner wall of the water tank body 4, and a silicone hose with a diameter of 8mm is put on the organic glass tube, and the switch is controlled by a water stop clamp. The lower flange 8 is located at the lower end of the water tank 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. 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] Example 2

[0041] This embodiment provides a method for simulating the phosphorus cycle process of sediments in estuaries under different turbidity conditions using the device of embodiment 1, including the following steps:

[0042] Step 1: Prepare several devices that simulate the phosphorus cycle process of sediments in estuaries under different turbidity conditions in a constant temperature and light-proof room. Open the upper flange 3 and add fresh sediment samples to the flume structure to a depth of 10 cm from the bottom of the flume structure. Then, add in-situ seawater or artificial seawater with a known phosphorus content to a depth of about 28 cm. Secure the upper flange 3 to prevent vibration caused by the subsequent high-speed rotation of the motor 1.

[0043] Step 2: The water tank structure is left to stand. If there is no leakage after 24 hours, it indicates that the water tank structure is well sealed. The probe structure 12 is used to measure the turbidity of the water about 10 cm below the surface of the water tank structure. When the turbidity is less than 1, it can be determined 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 3: According to the historical measured turbidity values of the maximum turbidity zone in the estuary, several turbidity values are selected for experimentation. For example, turbidity values of 0, 50, 100, and 200 can be selected for experimentation, wherein a device simulating the phosphorus circulation process of sediments under different turbidity conditions in the estuary with a turbidity value of 0 is used as a blank control. The probe structure 12 is inserted 10 cm underwater, and the stirring structures of the devices simulating the phosphorus circulation process of sediments under different turbidity conditions in the estuary are turned on to stabilize the turbidity values of the water bodies of the respective water tank structures to corresponding preset values. The corresponding rotation speed of each stirring structure is recorded at this time, and then each water tank structure is allowed 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, surface sediment samples (0-1 cm) and overlying water samples are collected from 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 in this embodiment, which are the first, third and sixth sampling ports 6 from top to bottom), and in-situ seawater or artificial seawater is added to the original height. One experimental cycle is divided into a suspension stage and a sedimentation stage. One experimental cycle is 24 hours. During the suspension stage, the stirring structure is turned on and adjusted to the corresponding speed so that the water body of each water tank structure reaches the preset turbidity condition and is maintained for 8 hours. During this period, the dissolved oxygen, salinity, water temperature and pH value in the overlying water are regularly observed, and the stirring structure is turned off to 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 entire experimental process is divided into an early incubation stage (the first to third experimental cycles) and a late incubation stage (the fourth to ninth experimental cycles), and collect surface sediment samples and overlying water samples after the suspension stage of each cycle. Immediately after each sampling, replenish in situ seawater or artificial seawater, and after the suspension stage of any experimental cycle in the early incubation stage (for example, the first experimental cycle) and the suspension stage of any experimental cycle in the late incubation 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 the high-resolution pore water sampling (HR-Peeper) device after 48 hours, and place them in a moist, light-proof aluminum foil sealed bag;

[0047] Step 6: Measure the phosphorus content of various forms, phosphatase activity, and abundance of phosphorus cycling genes in the collected overlying water, pore water, and sediment samples. Analyze and organize the data based on different turbidity conditions and time. After the experiment, clean the device for repeated use.

[0048] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method using an apparatus simulating the phosphorus cycle in sediments under different turbidity conditions in an estuary, characterized by: The device for simulating the phosphorus cycle process in sediments under different turbidity conditions in an estuary 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 from top to bottom. 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. The device also includes a high-resolution pore water sampling device and a thin film diffusion gradient device. The high-resolution pore water sampling device and the thin film diffusion gradient device can extend into the water tank structure. The method using an apparatus simulating the phosphorus cycling process in sediments under different turbidity conditions in an estuary comprises the following steps: Step 1: Prepare several devices to simulate the phosphorus cycling process of sediments in estuaries under different turbidity conditions in a constant temperature and light-proof room. Add fresh sediment samples to the flume structure, and then add in situ seawater or artificial seawater with known phosphorus content. Step 2: The water tank structure is allowed to stand still, and the turbidity of the water in the water tank structure is measured using the 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: Based on the historical measured turbidity values of the maximum turbidity zone in the estuary, several turbidity values are selected for the experiment, wherein a device simulating the phosphorus cycling process in 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 inserted into the water body, and the stirring structure of each device simulating the phosphorus cycling process in the sediment under different turbidity conditions in the estuary is turned on to stabilize the turbidity value of the water body in each water tank structure to a corresponding preset value. The rotation speed corresponding to each stirring structure at this time is recorded, and then each water tank structure is allowed 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, surface sediment samples and overlying water samples are collected from each flume structure, and in-situ seawater or artificial seawater is replenished to the original height. One experimental cycle is divided into a suspension phase and a settling phase. During the suspension phase, the stirring structure is turned on and adjusted to the corresponding speed to make the water in each flume structure reach the preset turbidity conditions. During this period, the dissolved oxygen, salinity, water temperature and pH value of the overlying water are regularly observed. The stirring structure is turned off to allow the water-sediment to enter the settling phase. Step 5: Repeat the above experimental cycle several times. The entire experimental process is divided into an early incubation stage and a late incubation stage. After the suspension stage of each cycle, surface sediment samples and overlying water samples are collected. In situ seawater or artificial seawater is immediately replenished after each sampling. After the suspension stage of any experimental cycle in the early incubation stage and any experimental cycle in the late incubation stage, the high-resolution pore water sampling device and the thin film diffusion gradient device are inserted into the sediment and removed 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.

2. The method according to claim 1, wherein: The probe structure includes a turbidity probe, a dissolved oxygen probe, a salinity probe, a temperature probe and a pH probe.

3. The method according to claim 1, wherein: 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.

4. The method according to claim 3, wherein: The motor is arranged on the water tank structure through a bracket, and the bracket is made of organic glass.

5. The method according to claim 3, wherein: The transmission rod and the propeller are both made of corrosion-resistant materials.

6. The method according to claim 1, wherein: The water tank structure is made of organic glass, 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.

7. The method according to claim 6, wherein: The upper flange and the lower flange are respectively connected to the water tank body in a detachable manner. Water-stop pads are provided between the upper flange and the water tank body, and between the lower flange and the water tank body.

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