Sediment microdomain element and microorganism synchronous detection device and method

Abstract

The invention relates to a sediment micro-domain element and microorganism synchronous detection device and method, and belongs to the technical field of environment monitoring, and the sediment micro-domain element and microorganism synchronous detection device comprises a shielding cover and an in-situ detector; the shielding case is provided with a mounting hole and a vent hole, the shielding case is provided with a functional panel, and the functional panel is used for adjusting the temperature in the shielding case; the in-situ detector is arranged in the mounting hole in the vertically downward direction, the in-situ detector comprises a shell and a DGT film, multiple sets of horizontal tooth grooves are formed in one side of the shell, the multiple sets of tooth grooves are evenly formed in one side of the shell in the vertical direction, notches of the tooth grooves are in an upward state, the DGT film is installed in the shell, and the DGT film is arranged in the shell. A detection window is formed in the side, away from the tooth groove, of the shell. By means of the detection device and method integrating DGT chemical passive sampling and microorganism active sampling, in-situ synchronous monitoring of elements and microorganisms in different depths of sediment is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental monitoring, and particularly relates to a device and method for synchronously detecting sediment microdomain elements and microorganisms. Background Art

[0002] The sediment-water interface, as the core area of material cycling and biological interaction in the aquatic ecosystem, is the key interface for regulating the migration and transformation of nutrients such as phosphorus and nitrogen and the dynamics of microbial communities. In recent years, the problem of lake eutrophication has become increasingly severe globally, with frequent occurrences of cyanobacterial blooms. The core cause is closely related to the occurrence form of phosphorus in sediments and the interface release process. Therefore, accurately analyzing the occurrence form of sediment phosphorus, the interface exchange law, and its response to environmental factors is the key scientific issue for preventing and controlling eutrophication and maintaining water environment safety.

[0003] The spatial distribution of phosphorus in the sediment-water interface has high heterogeneity. Traditional sediment detection technologies have the following significant limitations: it is easy to damage the physical structure of sediments, making it difficult to obtain real correlation data on phosphorus release and microbial activity; factors such as water flow disturbance and temperature fluctuation in natural waters are likely to interfere with the in-situ detection process; the detection of element distribution and the analysis of microbial communities are usually carried out independently, lacking a synchronous in-situ sampling method for the two at the microdomain scale; although the diffusive gradients in thin films (DGT) technology can achieve millimeter-scale high-resolution detection of available phosphorus, microbial analysis still relies on centimeter-scale layered sampling, and the spatial scale difference between the two is relatively large, making it difficult to reveal the phosphorus-microorganism interaction mechanism.

[0004] In view of the above technical phenomena, the present invention proposes a detection device and method that integrates DGT chemical passive sampling and microbial active sampling, and realizes the synchronous characterization of element concentration and microbial community in the sediment microdomain through innovative structural design. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and method for synchronously detecting sediment microdomain elements and microorganisms, which realizes the in-situ synchronous monitoring of elements and microorganisms at different depths of sediments through a detection device and method that integrates DGT chemical passive sampling and microbial active sampling.

[0006] A device for synchronously detecting sediment microdomain elements and microorganisms provided by the present invention adopts the following technical solutions: A device for synchronously detecting sediment microdomain elements and microorganisms includes a shielding cover, the shielding cover is provided with an installation hole and a ventilation hole, and the shielding cover is installed with a function panel, and the function panel is used to adjust the temperature inside the shielding cover; An in-situ detector is arranged in a mounting hole in a vertically downward direction. The in-situ detector includes a shell and a DGT membrane. Multiple groups of horizontal grooves are provided on one side of the shell. The multiple groups of grooves are evenly arranged on one side of the shell in a vertical direction. The groove openings are facing upward. The DGT membrane is installed in the shell. A detection window is provided on the side of the shell away from the groove.

[0007] Preferably, the shielding cover is made of stainless steel, a heating wire is provided on the inner wall of the shielding cover, and the functional panel is used to control the temperature of the heating wire.

[0008] Preferably, the depth of the tooth groove is 0.5 cm, and the width of the tooth groove is 0.75-3 cm.

[0009] Preferably, the housing includes a front plate and a rear plate, a positioning groove for placing the DGT film is opened between the front plate and the rear plate, and the edges of the front plate and the rear plate are fixedly connected by bolts; The tooth groove is arranged on a side of the rear plate facing away from the front plate, and the detection window is arranged on the front plate.

[0010] Preferably, the size of the positioning groove is larger than the size of the detection window, and the DGT film is in a state of being tightly attached to the front plate and the rear plate.

[0011] Preferably, the shell is made of plastic.

[0012] The present invention also provides a detection method using the above-mentioned sediment micro-element and microorganism synchronous detection device, which adopts the following technical solution: A method for synchronous detection of sediment micro-domain elements and microorganisms, comprising the following steps: S1. Install the shielding cover and the in-situ detector, and insert them vertically downward into the sediment to be tested. Operate the function panel to adjust the temperature inside the shielding cover to 25°C and maintain it for 24 hours. S2. Slowly remove the shielding cover and the in-situ detector from the sediment in a vertically upward direction, disassemble the in-situ detector from the shielding cover, remove the excess sediment outside each set of tooth grooves of the in-situ detector, and clean the sediment particles sticking to the surface of the DGT membrane with deionized water; S3, taking out the sediment in each group of tooth grooves and sealing them in a centrifuge tube for later use; S4. Disassemble the housing of the in-situ detector and remove the DGT membrane. Cut the membrane into several unit membrane blocks according to the spacing between the teeth and grooves, and place each unit membrane block in a centrifuge tube. Elute the trace elements adsorbed on the surface of the unit modules to obtain an eluate, and measure the phosphorus content in the eluate. Calculate the effective phosphorus diffusion flux along the depth gradient of the sediment profile based on the area of the cut DGT membrane and the time it was deployed in the sediment. Or disassemble the housing of the in-situ detector and take out the DGT membrane. Place the DGT membrane in a pre-prepared molybdenum blue chromogenic solution for chromogenic reaction. After soaking for 15 minutes, take it out and wash away the remaining molybdenum blue chromogenic solution on the surface of the DGT membrane with deionized water. Then place the chromogenic DGT membrane in a scanner to obtain the chromogenic image.

[0013] Preferably, the method for eluting the trace elements adsorbed on the surface of the elution unit module in step S4 is as follows: Take a 0.5 mol / L sodium hydroxide solution and place it in a centrifuge tube. After soaking the unit module for 24 hours, an eluate is obtained, and the phosphorus content in the eluate is detected using ICP-MS.

[0014] In summary, the present invention includes the following beneficial technical effects: 1. This application includes a shielding cover and an in-situ detector. The in-situ detector is arranged inside the shielding cover. The function of the shielding cover reduces the influence of the in-situ detector being impacted by water flow. The tooth groove on one side of the in-situ detector is used to collect microorganisms in sediments at different depths, and the DGT membrane on the other side of the in-situ detector is used to in-situ adsorb phosphorus elements in sediments at different depths, realizing non-destructive in-situ synchronous monitoring through an integrated device.

[0015] 2. This application can obtain the element content information of sediments at different depths based on the spacing between the tooth grooves of adjacent groups, and can also combine chemical imaging technology to characterize the spatial distribution information of available phosphorus in the sediment profile with higher resolution. Description of the Drawings

[0016] Figure 1 is a schematic structural diagram of a device for synchronous detection of sediment microdomain elements and microorganisms in an embodiment of the present invention.

[0017] Figure 2 is a schematic structural diagram of the in-situ detector.

[0018] Figure 3 is a schematic structural diagram of the in-situ detector under side view.

[0019] Figure 4 is a schematic structural diagram of the shielding cover under bottom view.

[0020] Figure 5 is a schematic cross-sectional structural diagram of the in-situ detector under top view.

[0021] Figure 6 is a flowchart of a method for synchronous detection of sediment microdomain elements and microorganisms in an embodiment of the present invention.

[0022] Figure 7 is a one-dimensional spatial distribution diagram of available phosphorus and bacterial communities in the sediment profile and overlying water of a fast-flowing river.

[0023] Figure 8It is a one-dimensional spatial distribution diagram of available phosphorus and bacterial communities in the sediment profile of a slow-flowing river and the overlying water.

[0024] Figure 9 It is a one-dimensional spatial distribution diagram of available phosphorus and bacterial communities in the sediment profile of a static lake and the overlying water.

[0025] Figure 10 It is a standard curve of available phosphorus flux - gray value.

[0026] Figure 11 It is a two-dimensional spatial distribution diagram of available phosphorus in the sediment profiles of a rapid-flowing river, a slow-flowing river, and a static lake.

[0027] Explanation of reference numerals: 1. Shielding cover; 11. Mounting hole; 12. Ventilation hole; 13. Function panel; 14. Heating wire; 2. In-situ detector; 21. Housing; 211. Front plate; 212. Rear plate; 213. Tooth groove; 214. Detection window; 215. Positioning groove; 216. Bolt; 22. DGT membrane. Detailed implementation manners

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will combine the attached Figures 1-11 The technical solutions of the present invention will be described clearly and completely. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Embodiment

[0030] Embodiment 1 The following will, with reference to the accompanying drawings, elaborate on some embodiments of the present invention. In some embodiments of the present invention, a device for synchronously detecting microdomain elements and microorganisms in sediments is provided. Refer to Figure 1 , a device for synchronously detecting microdomain elements and microorganisms in sediments includes a shielding cover 1 and an in-situ detector 2; a ventilation hole 12 is provided at the top of the shielding cover 1, and multiple groups of ventilation holes 12 are evenly dispersed at the top of the shielding cover 1. The ventilation hole 12 ensures the exchange of gases inside the shielding cover 1 and the external environment, avoiding the formation of an anaerobic environment inside the shielding cover 1, which may affect subsequent detection results; a mounting hole 11 for vertically installing the in-situ detector 2 is provided at the central position of the top of the shielding cover 1; and a function panel 13 is further installed at the top of the shielding cover 1, and the function panel 13 is used to adjust and monitor the temperature inside the shielding cover 1.

[0031] Refer to Figure 2 and Figure 3The in-situ detector 2 includes a shell 21 and a DGT membrane 22. One side of the shell 21 is provided with multiple groups of horizontal tooth grooves 213. The multiple groups of tooth grooves 213 are evenly arranged on one side of the shell 21 in the vertical direction, and the notches of the tooth grooves 213 are facing upward. The multiple groups of tooth grooves 213 are used to collect sediment samples of different depths. The DGT membrane 22 is installed in the shell 21, and a detection window 214 is provided on the side of the shell 21 away from the tooth grooves 213, that is, the DGT membrane 22 is in direct contact with the sediment. The DGT membrane 22 is used for in-situ detection of trace elements and effective state content in the sediment, and subsequent chemical analysis or imaging detection is carried out. Combined with Figure 1 The in-situ detector 2 is mounted on the shielding cover 1. The shielding cover 1 and the in-situ detector 2 are placed vertically downward in the sediment to be tested. At this point, the vent 12 is above the water surface. The temperature inside the shielding cover 1 is adjusted by manipulating the function panel 13. After a period of time, sampling is complete. The shielding cover 1 and the in-situ detector 2 are then slowly removed vertically upward from the sediment. During this process, the shielding cover 1 reduces the impact of water flow on the in-situ detector 2.

[0032] Reference Figure 3 and Figure 4 In this embodiment, the depth of the tooth groove 213 is 0.5 cm, and the width of the tooth groove 213 ranges from 0.75 to 3 cm, allowing for detection of sediments at different depths and achieving centimeter-level spatial resolution. The shielding cover 1 in this embodiment is made of stainless steel, and a heating wire 14 is installed on the inner wall of the shielding cover 1. By operating the function panel 13, the heating state of the heating wire 14 is changed to control the temperature within the shielding cover 1 to a preset temperature.

[0033] Reference Figure 3 and Figure 5 In this embodiment, the housing 21 is made of plastic. The housing 21 includes a front plate 211 and a rear plate 212. A positioning groove 215 for placing the DGT membrane 22 is provided between the front plate 211 and the rear plate 212. Bolts 216 are provided at the edges of the front plate 211 and the rear plate 212. The front plate 211 and the rear plate 212 are fixed together by the bolts 216. The DGT membrane 22 is clamped by the front plate 211 and the rear plate 212, that is, the DGT membrane 22 is tightly attached to the front plate 211 and the rear plate 212. The size of the positioning groove 215 is larger than the size of the detection window 214, and the size of the DGT membrane 22 is larger than the size of the detection window 214, which prevents the DGT membrane 22 from detaching from the detection window 214 from the housing 21. The tooth groove 213 is provided on a side of the rear plate 212 away from the front plate 211 , and the detection window 214 is provided on the front plate 211 , thereby preventing sediment on the tooth groove 213 from contaminating the DGT membrane 22 .

[0034] Example 2 Based on the same technical concept, the present invention also provides a method for synchronous detection of sediment micro-domain elements and microorganisms using the above embodiment. Figures 1-6 The method for simultaneous detection of elements and microorganisms in sediments includes the following steps: 1) Install the shielding cover 1 and the in-situ detector 2, and insert them vertically downward into the sediment to be detected. Operate the function panel 13 to adjust the temperature inside the shielding cover 1 to 25°C and maintain it for 24 hours. 2) After completing step 1), slowly remove the shielding cover 1 and the in-situ detector 2 from the sediment in a vertically upward direction, remove the in-situ detector 2 from the shielding cover 1, remove the excess sediment outside each group of tooth grooves 213 of the in-situ detector 2, and clean the sediment particles sticking to the surface of the DGT membrane 22 with deionized water; 3) Separately taking out the sediment in each group of tooth grooves 213 in step 2) and sealing them in 1.5 mL centrifuge tubes for later use; 4) Disassemble the housing 21 of the in-situ detector 2 in step 2) and remove the DGT membrane 22. Cut the DGT membrane 22 into several unit membrane blocks according to the intervals of the tooth grooves 213 and place them in 1.5 mL centrifuge tubes respectively. Take 2 mL of 0.5 mol / L sodium hydroxide solution and place it in the centrifuge tube. Soak the unit module in the sodium hydroxide solution for 24 hours to elute the trace elements adsorbed on the surface of the unit module to obtain an eluate. Use ICP-MS to detect the phosphorus content in the eluate. Calculate the effective phosphorus diffusion flux along the depth gradient of the sediment profile based on the area of the cut DGT membrane and the time it is deployed in the sediment. Alternatively, disassemble the housing 21 of the in-situ detector 2 in step 2) and take out the DGT membrane 22, place the DGT membrane 22 in a pre-configured molybdenum blue color-developing solution for color development, soak for 15 minutes and then take it out, wash off the molybdenum blue color-developing solution remaining on the surface of the DGT membrane 22 with deionized water, and then place the colored DGT membrane 22 in a scanner to obtain a colored image.

[0035] Test Case

[0036] Test Example 1 1) Sediment pre-cultivation In the upper reaches of Qingshan Lake in Hangzhou City, Zhejiang Province, rapids river sediments were selected as pre-cultured sediments, and the corresponding sediments and overlying water were collected in advance; the collected sediments were placed in sedimentation barrels, and the corresponding overlying water was added for pre-culture for 14 days to simulate the sediment development process under natural conditions.

[0037] 2) Installation of the device Select an in-situ detector with a tooth groove width of 3 cm, install the shielding cover and the in-situ detector, and place the shielding cover and the in-situ detector vertically downward into the sediment after step 1) and 14 days of cultivation. Control the function panel to adjust the internal temperature of the shielding cover to 25 °C and maintain for 24 hours.

[0038] 3) Pretreatment of in-situ sampler After completing step 2), slowly remove the shielding cover and the in-situ detector from the sediment vertically upward. Disassemble the in-situ detector from the shielding cover, level the sediment in each tooth groove of the in-situ detector with a small knife, remove the excess sediment outside each tooth groove, and collect the sediment in the tooth grooves at the same depth for microbial community analysis. Set 3 parallels and seal them in 1.5 mL centrifuge tubes respectively; Wash the sediment particles sticking to the surface of the DGT membrane with deionized water, carefully disassemble the housing of the in-situ detector and take out the DGT membrane. Place the DGT membrane on a clean acrylic plate, and cut the DGT membrane into several small pieces according to the interval of the tooth grooves with a clean small knife, and place them in 1.5 mL centrifuge tubes respectively. Add 2 mL of 0.5 mol / L sodium hydroxide solution to the centrifuge tubes and soak for 24 hours to elute the trace elements adsorbed on the surface of the DGT membrane. Detect the phosphorus content in the eluate by ICP-MS, and calculate the effective phosphorus diffusion flux along the depth gradient of the sediment profile according to the area of the cut DGT membrane and the time of deployment in the sediment.

[0039] Refer to Figure 7 0 Figure 7 is the one-dimensional spatial distribution map of available phosphorus and bacterial communities in the sediment profile and overlying water of a rapids river with a resolution of 3 cm, where Figure 7 (a) is the one-dimensional distribution of available phosphorus content in the sediment profile and overlying water of the rapids river; Figure 7 (b) is the one-dimensional distribution of Gammaproteobacteria ( Gammaproteobacteria ) in the sediment of the rapids river; Figure 7 (c) is the one-dimensional distribution of Anaerolineae ( Anaerolineae ) in the sediment of the rapids river; Figure 7 (d) is the one-dimensional distribution of Bacteroidetes ( Bacteroidia ) in the sediment of the rapids river. The vertical distribution characteristics show that the available phosphorus content at the sampling points all shows a trend of first increasing and then decreasing with the increase of depth, but the specific distribution patterns are significantly different. In the overlying water layer (0 - 6 cm), the available phosphorus content increases significantly with depth, indicating an obvious process of phosphorus sedimentation and enrichment in the water body. In the sediment layer (6 - 21 cm), the available phosphorus in the sediment of the rapids river first increases at a depth of 9 - 12 cm, and then the content fluctuates and decreases, which may be related to the phosphorus fixation-release balance caused by its alkaline environment and high calcium content; The bacterial community in the sediments of the rapid - flowing river is mainly composed of Gammaproteobacteria, and the change range of relative abundance is small, indicating that it plays a key role in the sediment ecosystem; Anaerolineae and Bacteroidetes show good adaptability to the sediments of the rapid - flowing river. And the bacterial community structure is relatively stable in the vertical direction, and the change of relative abundance of the main bacterial classes is small, indicating that the environmental conditions of the rapid - flowing river sediments may have little impact on the bacterial community in the vertical direction.

[0040] Test Example 2 1). Sediment pre - culture In the middle and lower reaches of the Nantiao River in Hangzhou City, Zhejiang Province, slow - flowing river sediments were selected as the sediments for pre - culture, and the corresponding sediments and overlying water were collected in advance; The collected sediments were placed in sediment buckets and the corresponding overlying water was added for pre - culture for 14 days to simulate the sediment development process under natural conditions.

[0041] 2). Installation of the device An in - situ detector with a tooth - groove width of 1.5 cm was selected. The shielding cover and the in - situ detector were installed, and the shielding cover and the in - situ detector were placed vertically downward into the sediments after culturing for 14 days in step 1). The function panel was controlled to adjust the internal temperature of the shielding cover to 25 °C and maintained for 24 hours.

[0042] 3). Pre - treatment of the in - situ sampler After completing step 2), the shielding cover and the in - situ detector were slowly taken out from the sediments in the vertical upward direction. The in - situ detector was disassembled from the shielding cover. The sediments in each tooth - groove of the in - situ detector were leveled with a small knife, and the excess sediments outside each tooth - groove were removed. The sediments in the tooth - grooves at the same depth were collected for microbial community analysis, and 3 parallel groups were set up and respectively encapsulated in 1.5 mL centrifuge tubes; The sediment particles sticking to the surface of the DGT membrane were washed with deionized water. The housing of the in - situ detector was carefully disassembled and the DGT membrane was taken out. The DGT membrane was placed on a clean acrylic plate, and the DGT membrane was cut into several small pieces according to the interval of the tooth - grooves with a clean small knife and placed in 1.5 mL centrifuge tubes respectively. 2 mL of 0.5 mol / L sodium hydroxide solution was added to the centrifuge tubes and soaked for 24 hours to elute the trace elements adsorbed on the surface of the DGT membrane. The content of phosphorus in the eluate was detected by ICP - MS, and the effective phosphorus diffusion flux along the depth gradient of the sediment profile was calculated according to the area of the cut DGT membrane and the time of deployment in the sediments.

[0043] Refer to Figure 8 , Figure 8 is the one - dimensional spatial distribution map of available phosphorus and bacterial community in the slow - flowing river sediment profile and overlying water with a resolution of 1.5 cm, where Figure 8 (a) is the one - dimensional distribution of available phosphorus content in the slow - flowing river sediment profile and overlying water;Figure 8 (b) γ-Proteobacteria in slow-flow river sediments ( Gammaproteobacteria )’s one-dimensional distribution; Figure 8 (c) Anaerobic Fungi in slow-flowing river sediments ( Anaerolineae )’s one-dimensional distribution; Figure 8 (d) Bacteroidetes in slow-flow river sediments ( Bacteroidia ). Vertical distribution characteristics show that the available phosphorus content at the sampling points first increases and then decreases with increasing depth, but there are obvious differences in the specific distribution patterns. In the overlying water layer (0-6 cm), the available phosphorus content increases significantly with depth, indicating that there is a clear phosphorus precipitation and enrichment process in the water body. In the sedimentary layer (6-21 cm), the available phosphorus content of slow-flowing river sediments is highest at a depth of 12-15 cm, which may be related to anoxic reducing conditions and microbial action; The bacterial community structure in slow-flowing river sediments exhibits complex changes. The abundance of Anaerobic Fungi first increases and then decreases with depth, while the abundance of Bacteroidetes is relatively high. This reflects the complexity of the sediment environment in slow-flowing rivers, where environmental factors at different depths exert a comprehensive influence on bacterial community distribution. The overall available phosphorus content in slow-flowing river sediments is high, with hotspots. The increasing and then decreasing abundance of Anaerobic Fungi may explain the phosphorus-iron cycling mediated by microorganisms in anaerobic environments.

[0044] Test Example 3 1) Sediment pre-cultivation In the lakes within the Zijingang Campus of Zhejiang University, static lake sediments were selected as pre-cultured sediments, and the corresponding sediments and overlying water were collected in advance; the collected sediments were placed in sedimentation barrels, and the corresponding overlying water was added for pre-culture for 14 days to simulate the sediment development process under natural conditions.

[0045] 2) Installation of the device An in-situ detector with a tooth groove width of 0.75 cm was selected, and a shielding cover and the in-situ detector were installed. The shielding cover and the in-situ detector were placed vertically downward in the sediment obtained in step 1) and after 14 days of incubation. The internal temperature of the shielding cover was adjusted to 25°C by operating the function panel for 24 hours.

[0046] 3) In-situ sampler pretreatment After step 2) is completed, slowly take out the shielding cover and in-situ detector from the sediment in the vertically upward direction. Disassemble the in-situ detector from the shielding cover, level the sediment in each set of tooth grooves of the in-situ detector with a small knife, remove the excess sediment outside each set of tooth grooves, and collect the sediment in the tooth grooves at the same depth for microbial community analysis. Set 3 parallels and encapsulate them in 1.5 mL centrifuge tubes respectively; Wash the sticky sediment particles on the surface of the DGT membrane with deionized water, carefully disassemble the housing of the in-situ detector and take out the DGT membrane. Place the DGT membrane on a clean acrylic plate, cut the DGT membrane into several small pieces according to the interval of the tooth grooves with a clean small knife, and place them in 1.5 mL centrifuge tubes respectively. Add 2 mL of 0.5 mol / L sodium hydroxide solution to the centrifuge tubes and soak for 24 hours to elute the trace elements adsorbed on the surface of the DGT membrane. Detect the phosphorus content in the eluate by ICP-MS, and calculate the effective phosphorus diffusion flux along the depth gradient of the sediment profile according to the area of the cut DGT membrane and the time of deployment in the sediment.

[0047] Refer to Figure 9 , Figure 9 is the one-dimensional spatial distribution map of available phosphorus and bacterial communities in the sediment profile and overlying water of a static lake with a resolution of 0.75 cm, where Figure 9 (a) is the one-dimensional distribution of available phosphorus content in the sediment profile and overlying water of a static lake; Figure 9 (b) is the one-dimensional distribution of Gammaproteobacteria ( Gammaproteobacteria ) in the sediment of a static lake; Figure 9 (c) is the one-dimensional distribution of Anaerolineae ( Anaerolineae ) in the sediment of a static lake; Figure 9 (d) is the one-dimensional distribution of Bacteroidetes ( Bacteroidia ) in the sediment of a static lake. The vertical distribution characteristics show that the available phosphorus content at the sampling point first increases and then decreases with the increase of depth, but the specific distribution pattern shows obvious differences. In the overlying water layer (0 - 6 cm), the available phosphorus content increases significantly with the increase of depth, indicating that there is an obvious process of phosphorus sedimentation and enrichment in the water body. In the sediment layer (6 - 21 cm), the available phosphorus content in the sediment of the static lake is the highest at a depth of 12 - 15 cm, which may be related to its higher clay content and neutral pH conditions; The change of the bacterial community structure in the sediment of the static lake with depth is relatively significant. Anaerolineae slightly increases with depth, while Bacteroidetes decreases with depth. This change indicates that there is a significant environmental gradient in the vertical direction of the sediment of the static lake, which in turn affects the distribution of the bacterial community.

[0048] Test Example 4 1), DGT imaging analysis During the sediment cultivation process in Test Examples 1-3, three additional groups of devices for synchronously detecting sediment microdomain elements and microorganisms were arranged for in-situ chemical imaging of sediments. The sediment particles adhering to the surface of the DGT membrane were washed with deionized water. The DGT membrane was carefully removed from the housing and placed in a pre-prepared molybdenum blue color-developing solution for color development reaction. After soaking for 15 minutes, it was taken out, and the molybdenum blue color-developing solution remaining on the surface of the DGT membrane was washed off with deionized water. Subsequently, the color-developed DGT membrane was placed in a scanner to obtain a color-developed image for subsequent quantitative analysis.

[0049] 2) Calibration curve drawing Phosphorus standard solutions with phosphorus concentrations of 0, 20, 50, 100, 200, 500, 750, 1000, and 2000 μg / L were prepared using a phosphorus standard substance. The disc-shaped DGT membrane was placed in the P solution and adsorbed for 12 h, then developed in the molybdenum blue color-developing solution. The colored DGT membrane was immediately washed several times with deionized water at 4°C to wash off the residual developer on the surface, and then continued to be soaked in deionized water for 5 min (to promote the termination of the color development reaction). The DGT membrane was taken out, the water on the surface was wiped off with filter paper, and placed on a scanner (face down). After setting the resolution to 1200 dpi and scanning to obtain an image, the ImageJ software was used to convert the image to grayscale. The exponential function with the highest correlation was selected to fit the P accumulation amount per unit area on the membrane and the corresponding gray intensity on the membrane surface. Referring to Figure 10 , it is the standard curve (G(f)) of the accumulation amount per unit area of the analyte (f) - gray value (G).

[0050] Referring to Figure 11 , Figure 11 is the two-dimensional spatial distribution map of available phosphorus in the profiles of sediments in fast-flowing rivers, slow-flowing rivers, and static lakes. The sediments in fast-flowing rivers show strong spatial variability at a depth of 0-3 cm, while being relatively uniform in the deep layer; the available phosphorus content in the sediments of slow-flowing rivers is generally high and evenly distributed, but obvious hot spots can still be seen at a depth of 12-15 cm; large-area hot spots are formed at a depth of 12-15 cm in the sediments of static lakes, and the distribution is relatively continuous. Thus, the strong water flow in fast-flowing rivers leads to uneven distribution of surface available phosphorus; while the sediments in slow-flowing rivers and static lakes form a more continuous available phosphorus distribution pattern due to the relatively stable water environment.

[0051] In summary, in the sediment layer, enrichment regions of available phosphorus appeared in the rapid-flow river sediments, slow-flow river sediments, and still lake sediments within specific depth ranges. After that, as the sediment layer depth increased, the content of available phosphorus showed a gradually decreasing trend. This result indicates that external water flow and sediment particle size distribution differences are the main environmental factors causing the heterogeneous distribution of phosphorus elements in sediments. In addition, the redox gradients of different sediments along the depth shape different microbial communities, which in turn have an important impact on the biogeochemical cycle of phosphorus elements.

[0052] The above are all preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A device for synchronously detecting sediment micro-domain elements and microorganisms, characterized in that, including a shielding cover (1), the shielding cover (1) is provided with a mounting hole (11) and a ventilation hole (12), the shielding cover (1) is installed with a function panel (13), and the function panel (13) is used to adjust the temperature inside the shielding cover (1); an in-situ detector (2), the in-situ detector (2) is arranged in the mounting hole (11) in the vertically downward direction, the in-situ detector (2) includes a housing (21) and a DGT membrane (22), one side of the housing (21) is provided with a plurality of groups of horizontal tooth grooves (213), and the plurality of groups of tooth grooves (213) are uniformly arranged along the vertical direction on one side of the housing (21), the notch of the tooth groove (213) faces upward, the DGT membrane (22) is installed in the housing (21), and a detection window (214) is provided on the side of the housing (21) facing away from the tooth groove (213).

2. The synchronous detection device for sediment microdomain elements and microorganisms according to claim 1, characterized in that, The material of the shielding cover (1) is stainless steel, and a heating wire (14) is arranged on the inner wall of the shielding cover (1), and the function panel (13) is used to control the temperature of the heating wire (14).

3. A device for synchronously detecting sediment microdomain elements and microorganisms according to claim 1, characterized in that, The depth of the tooth groove (213) is 0.5 cm, and the width of the tooth groove (213) is 0.75 - 3 cm.

4. The synchronous detection device for sediment microdomain elements and microorganisms according to claim 1, characterized in that, The housing (21) includes a front plate (211) and a rear plate (212), a positioning groove (215) for placing the DGT membrane (22) is provided between the front plate (211) and the rear plate (212), and the edge parts of the front plate (211) and the rear plate (212) are fixedly connected by bolts (216); The tooth groove (213) is arranged on the side of the rear plate (212) facing away from the front plate (211), and the detection window (214) is arranged on the front plate (211).

5. The synchronous detection device for sediment microdomain elements and microorganisms according to claim 4, characterized in that, The size of the positioning groove (215) is larger than the size of the detection window (214), and the DGT membrane (22) is in a state of being closely attached to the front plate (211) and the rear plate (212).

6. The synchronous detection device for sediment microdomain elements and microorganisms according to claim 4, characterized in that The material of the housing (21) is plastic.

7. A detection method using the sediment microdomain element and microorganism synchronous detection device according to any one of claims 1-6, characterized in that, including the following steps: S1. Install the shielding cover (1) and the in-situ detector (2), and insert them vertically downward into the sediment to be detected. Operate the function panel (13) to adjust the temperature inside the shielding cover (1) to 25 °C and keep it for 24 h; S2. Slowly take out the shielding cover (1) and the in-situ detector (2) vertically upward from the sediment, disassemble the in-situ detector (2) from the shielding cover (1), remove the excess sediment outside each group of tooth grooves (213) of the in-situ detector (2), and wash the sediment particles sticking to the surface of the DGT membrane (22) with deionized water; S3. Take out the sediment in each group of tooth grooves (213) respectively and encapsulate it in a centrifuge tube for standby; S4. Disassemble the housing (21) of the in-situ detector (2) and take out the DGT membrane (22). Cut the DGT membrane (22) into several unit membrane blocks according to the interval of the tooth grooves (213) and place them in centrifuge tubes respectively. Elute the trace elements adsorbed on the surface of the unit module to obtain an eluate, and detect the phosphorus content in the eluate. Calculate the effective phosphorus diffusion flux along the depth gradient of the sediment profile according to the area of the cut DGT membrane and the time of deployment in the sediment; Or disassemble the housing (21) of the in-situ detector (2) and take out the DGT membrane (22). Place the DGT membrane (22) without cutting into a pre-prepared molybdenum blue chromogenic solution for chromogenic reaction. After soaking for 15 minutes, take it out and wash away the remaining molybdenum blue chromogenic solution on the surface of the DGT membrane (22) with deionized water. Then place the chromogenic DGT membrane (22) in a scanner to obtain the chromogenic image.

8. A method for synchronous detection of sediment microdomain elements and microorganisms according to claim 7, characterized in that The method for eluting the trace elements adsorbed on the surface of the elution unit module in the step S4 is as follows: Take 0.5 mol / L sodium hydroxide solution and place it in a centrifuge tube. After the unit module is soaked for 24 hours, an eluate is obtained, and the phosphorus content in the eluate is detected using ICP-MS.

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