A device and method for synchronous detection of micro-domain elements and microorganisms in sediments

Abstract

The present application relates to a kind of sediment micro-domain element and microbial synchronous detection device and method, belong to environmental monitoring technical field, including shield and in-situ detector;The shield is equipped with mounting hole and air hole, the shield is equipped with function panel, the function panel is used to adjust the temperature in shield;The in-situ detector is set in mounting hole along vertically downward direction, the in-situ detector includes shell and DGT membrane, the shell is equipped with multiple groups of horizontal tooth slot on one side, multiple groups of tooth slot are evenly arranged on the side of shell along vertical direction, the tooth slot mouth is in the state of upward, the DGT membrane is installed in shell, the shell is equipped with detection window on the side away from tooth slot.The present application is by DGT chemical passive sampling and microbial active sampling in one of the detection device and method, realizes the in-situ synchronous monitoring of element and microorganism in different depths of sediment.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring technology, and in particular to a device and method for simultaneous detection of micro-elements and microorganisms in sediments. Background Technology

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

[0003] The spatial distribution of phosphorus at the sediment-water interface is highly heterogeneous. Traditional sediment detection techniques have the following significant limitations: they easily damage the physical structure of sediments, making it difficult to obtain accurate correlation data between phosphorus release and microbial activity; factors such as water flow disturbance and temperature fluctuations in natural water bodies can easily interfere with the in-situ detection process; elemental distribution detection and microbial community analysis are usually carried out independently, lacking simultaneous in-situ sampling methods at the microscale; although the thin-film diffusion gradient technique (DGT) can achieve high-resolution detection of bioavailable phosphorus at the millimeter level, microbial analysis still relies on centimeter-level stratified sampling, and the large difference in spatial scale between the two makes it difficult to reveal the phosphorus-microbe interaction mechanism.

[0004] In response to the aforementioned technical phenomena, this invention proposes a detection device and method that integrates DGT chemical passive sampling and microbial active sampling, achieving simultaneous characterization of elemental concentration and microbial community within sediment microdomains through innovative structural design. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for simultaneous detection of elements and microorganisms in sediment microdomains. By integrating DGT chemical passive sampling and active microbial sampling into a detection device and method, in-situ synchronous monitoring of elements and microorganisms at different depths of sediments is achieved.

[0006] The present invention provides a device for simultaneous detection of micro-elements and microorganisms in sediment micro-domains, which adopts the following technical solution:

[0007] A device for simultaneous detection of micro-elements and microorganisms in sediment microdomains, comprising,

[0008] A shielding cover, wherein the shielding cover has mounting holes and ventilation holes, and the shielding cover is equipped with a function panel for adjusting the temperature inside the shielding cover;

[0009] An in-situ detector is installed in a mounting hole in a vertically downward direction. The in-situ detector includes a housing and a DGT membrane. Multiple sets of horizontal grooves are formed on one side of the housing. The multiple sets of grooves are evenly arranged in a vertical direction on one side of the housing. The groove openings are facing upward. The DGT membrane is installed inside the housing. A detection window is formed on the side of the housing away from the grooves.

[0010] Preferably, the shielding cover is made of stainless steel, and a heating wire is provided on the inner wall of the shielding cover. The function panel is used to control the temperature of the heating wire.

[0011] Preferably, the depth of the tooth groove is 0.5cm and the width of the tooth groove is 0.75-3cm.

[0012] Preferably, the housing includes a front plate and a rear plate, and a positioning groove for placing the DGT membrane is provided between the front plate and the rear plate. The edges of the front plate and the rear plate are fixedly connected by bolts.

[0013] The toothed groove is located on the side of the rear plate opposite to the front plate, and the detection window is located on the front plate.

[0014] Preferably, the size of the positioning groove is larger than the size of the detection window, and the DGT membrane is tightly fitted to the front and rear panels.

[0015] Preferably, the shell is made of plastic.

[0016] The present invention also provides a detection method using the above-mentioned simultaneous detection device for micro-elements and microorganisms in sediments, employing the following technical solution:

[0017] A method for simultaneous detection of micro-elements and microorganisms in sediment microdomains includes the following steps:

[0018] S1. Install the shield and in-situ detector, and insert them vertically downwards into the sediment to be tested. Use the control panel to adjust the temperature inside the shield to 25°C and maintain it for 24 hours.

[0019] S2. Slowly remove the shield and in-situ detector from the sediment in a vertically upward direction. Remove the in-situ detector from the shield, remove excess sediment from the outside of each set of tooth grooves of the in-situ detector, and wash the sediment particles adhering to the surface of the DGT membrane with deionized water.

[0020] S3. Take out the sediment from each set of tooth grooves and seal them in centrifuge tubes for later use;

[0021] S4. Disassemble the housing of the in-situ detector and remove the DGT membrane. Cut the DGT membrane into several unit membrane blocks according to the spacing of the grooves and place them in centrifuge tubes respectively. Elute the trace elements adsorbed on the surface of the unit modules to obtain the eluent. Detect the phosphorus content in the eluent. 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 takes to be deployed in the sediment.

[0022] Alternatively, the housing of the in-situ detector can be disassembled and the DGT membrane removed. The DGT membrane can be placed in a pre-prepared molybdenum blue colorimetric solution for colorimetric reaction. After soaking for 15 minutes, it can be removed and the molybdenum blue colorimetric solution remaining on the surface of the DGT membrane can be washed away with deionized water. Then, the colorimetric DGT membrane can be placed in a scanner to obtain the colorimetric image.

[0023] Preferably, the method for removing 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, the eluent is obtained, and the phosphorus content in the eluent is detected by ICP-MS.

[0024] In summary, the present invention has the following beneficial technical effects:

[0025] 1. This application includes a shield and an in-situ detector, wherein the in-situ detector is set inside the shield. The shield reduces the impact of water flow on the in-situ detector. The toothed groove on one side of the in-situ detector is used to collect microorganisms from sediments at different depths. The DGT membrane on the other side of the in-situ detector is used to adsorb phosphorus from sediments at different depths in situ. Non-destructive in-situ synchronous monitoring is achieved through an integrated device.

[0026] 2. This application can obtain elemental content information of sediments at different depths based on the spacing between adjacent groups of grooves, and can also combine chemical imaging technology to characterize the spatial distribution information of available phosphorus in sediment profiles with higher resolution. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a sediment micro-domain element and microbial synchronous detection device in an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the in-situ detector.

[0029] Figure 3 This is a schematic diagram of the in-situ detector viewed from the side.

[0030] Figure 4 This is a schematic diagram of the shield structure viewed from below.

[0031] Figure 5 This is a schematic diagram of the cross-sectional structure of the in-situ detector viewed from above.

[0032] Figure 6 This is a flowchart of a method for simultaneous detection of micro-elements and microorganisms in sediments according to an embodiment of the present invention.

[0033] Figure 7 It is a one-dimensional spatial distribution map of sediment profiles in fast-flowing rivers and of available phosphorus and bacterial communities in the overlying water.

[0034] Figure 8 It is a one-dimensional spatial distribution map of sediment profiles in slow-flowing rivers and of available phosphorus and bacterial communities in the overlying water.

[0035] Figure 9 It is a one-dimensional spatial distribution map of sediment profiles in a quiescent lake and the available phosphorus and bacterial communities in the overlying water.

[0036] Figure 10 It is the standard curve of effective phosphorus flux-ash value.

[0037] Figure 11 It is a two-dimensional spatial distribution map of available phosphorus in sediment profiles of fast-flowing rivers, slow-flowing rivers, and still lakes.

[0038] Explanation of reference numerals in the attached drawings: 1. Shielding cover; 11. Mounting hole; 12. Vent hole; 13. Function panel; 14. Heating wire; 2. In-situ detector; 21. Housing; 211. Front panel; 212. Rear panel; 213. Gear; 214. Detection window; 215. Positioning groove; 216. Bolt; 22. DGT membrane. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings. Figure 1-11 The technical solutions of the present invention have been clearly and completely described. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example

[0041] Example 1

[0042] The following detailed description of some embodiments of the present invention is provided with reference to the accompanying drawings. In some embodiments of the present invention, a device for simultaneous detection of micro-elements and microorganisms in sediment micro-domains is provided. (Refer to...) Figure 1A device for simultaneous detection of micro-elements and microorganisms in sediments includes a shield 1 and an in-situ detector 2. The top of the shield 1 is provided with ventilation holes 12, and multiple sets of ventilation holes 12 are evenly distributed on the top of the shield 1. The ventilation holes 12 ensure the exchange of gas inside the shield 1 with the external environment, and prevent the formation of an anaerobic environment inside the shield 1, which would affect the subsequent detection results. The center of the top of the shield 1 is provided with a mounting hole 11 for vertical installation of the in-situ detector 2. The top of the shield 1 is also provided with a function panel 13, which is used to adjust and monitor the temperature inside the shield 1.

[0043] Reference Figure 2 and Figure 3 The in-situ detector 2 includes a housing 21 and a DGT membrane 22. Multiple sets of horizontal grooves 213 are formed on one side of the housing 21, evenly arranged vertically along one side of the housing 21 with the groove openings facing upwards. These grooves are used to collect sediment samples at different depths. The DGT membrane 22 is installed inside the housing 21, and a detection window 214 is provided on the side of the housing 21 away from the grooves 213, allowing the DGT membrane 22 to directly contact the sediment. The DGT membrane 22 is used for in-situ detection of trace elements and their bioavailability in the sediment, followed by chemical analysis or imaging detection. Figure 1 The in-situ detector 2 is installed on the shield 1, and the shield 1 and the in-situ detector 2 are installed vertically downwards in the sediment to be tested. At this time, the vent 12 is above the water surface. The temperature inside the shield 1 is adjusted by controlling the function panel 13. After maintaining this temperature for a period of time, the sampling can be completed. The shield 1 and the in-situ detector 2 are then slowly removed from the sediment vertically upwards. During this process, the shield 1 reduces the impact of water flow on the in-situ detector 2.

[0044] Reference Figure 3 and Figure 4 In this embodiment, the depth of the groove 213 is 0.5 cm, and the width of the groove 213 is 0.75-3 cm, so as to detect sediments at different depths and control the spatial resolution at the centimeter level. The shield 1 in this embodiment is made of stainless steel, and a heating wire 14 is provided on the inner wall of the shield 1. By operating the function panel 13, the heating state of the heating wire 14 can be changed to control the temperature inside the shield 1 to a preset temperature.

[0045] Reference Figure 3 and Figure 5In 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 formed between the front plate 211 and the rear plate 212. Bolts 216 are provided on the edges of the front plate 211 and the rear plate 212, fixing the front plate 211 and the rear plate 212 together. The DGT membrane 22 is clamped between the front plate 211 and the rear plate 212, meaning 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, thus preventing the DGT membrane 22 from detaching from the housing 21 through the detection window 214. The tooth groove 213 is located on the side of the rear plate 212 away from the front plate 211, and the detection window 214 is located on the front plate 211, thereby preventing the deposits on the tooth groove 213 from contaminating the DGT membrane 22.

[0046] Example 2

[0047] Based on the same technical concept, this invention also provides a method for simultaneous detection of micro-elements and microorganisms in sediments using the methods described in the above embodiments. (Refer to...) Figures 1-6 The method for simultaneous detection of elements and microorganisms in sediments includes the following steps:

[0048] 1) Install the shield 1 and the in-situ detector 2, and insert them into the sediment to be detected in a vertically downward direction. Operate the function panel 13 to adjust the temperature inside the shield 1 to 25°C and maintain it for 24 hours.

[0049] 2) After completing step 1), slowly remove the shield 1 and the in-situ detector 2 from the sediment in a vertically upward direction. Remove the in-situ detector 2 from the shield 1, remove the excess sediment outside each set of tooth grooves 213 of the in-situ detector 2, and wash the sediment particles adhering to the surface of the DGT membrane 22 with deionized water.

[0050] 3) Take out the sediment from each set of tooth grooves 213 in step 2) and seal it in a 1.5mL centrifuge tube for later use;

[0051] 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 interval of the 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 tubes. Soak the unit modules in sodium hydroxide solution for 24 h to elute the trace elements adsorbed on the surface of the unit modules, thereby obtaining the eluent. Detect the phosphorus content in the eluent using ICP-MS. 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 of placement in the sediment.

[0052] Alternatively, disassemble the housing 21 of the in-situ detector 2 in step 2) and remove the DGT membrane 22. Place the DGT membrane 22 in the pre-prepared molybdenum blue color developing solution for color development reaction. After soaking for 15 minutes, remove it and wash off the molybdenum blue color developing solution remaining on the surface of the DGT membrane 22 with deionized water. Then place the color-developed DGT membrane 22 in the scanner to obtain the color-developed image.

[0053] Test case

[0054] Test Example 1

[0055] 1) Sediment pre-cultivation

[0056] In the upstream area of ​​Qingshan Lake in Hangzhou, Zhejiang Province, sediments from fast-flowing rivers were selected as pre-culture sediments, and corresponding sediments and overlying water were collected in advance. The collected sediments were placed in sedimentation tanks and the corresponding overlying water was added for pre-culture for 14 days to simulate the sediment development process under natural conditions.

[0057] 2) Installation of the device

[0058] Select an in-situ detector with a tooth groove width of 3cm, install a shield and in-situ detector, place the shield and in-situ detector in the sediment after step 1) and 14 days of culture in a vertically downward direction, operate the function panel, adjust the internal temperature of the shield to 25℃, and maintain it for 24 hours.

[0059] 3) In-situ sampler preprocessing

[0060] After completing step 2), slowly remove the shield and in-situ detector from the sediment in a vertically upward direction. Disassemble the in-situ detector from the shield. Use a knife to smooth the sediment in each set of grooves of the in-situ detector, removing excess sediment from the outside of each groove. Collect sediment from grooves at the same depth for microbial community analysis, setting up three parallel sets, each packaged in a 1.5 mL centrifuge tube. Wash the surface of the DGT membrane with deionized water to remove any adhering sediment particles. Carefully disassemble the housing of the in-situ detector and remove the DGT membrane. Place the DGT membrane on a clean acrylic plate. Use a clean knife to cut the DGT membrane into several small pieces according to the groove spacing, placing each piece in a 1.5 mL centrifuge tube. Add 2 mL of 0.5 mL of [unspecified ingredient] to the centrifuge tube. The DGT membrane was soaked in a sodium hydroxide solution of mol / L for 24 hours to elute the trace elements adsorbed on the surface of the membrane. The phosphorus content in the eluent was detected by ICP-MS. The effective phosphorus diffusion flux along the depth gradient of the sediment profile was calculated based on the area of ​​the DGT membrane cut and the time of deployment in the sediment.

[0061] Reference Figure 7 , Figure 7This is a one-dimensional spatial distribution map of sediment profiles in a fast-flowing river with a resolution of 3 cm, and of available phosphorus and bacterial communities in the overlying water. Figure 7 (a) A one-dimensional distribution of available phosphorus content in sediment profiles and overlying water in a fast-flowing river; Figure 7 (b) Gamma-Proteobacteria in sediments of fast-flowing rivers ( Gammaproteobacteria A one-dimensional distribution; Figure 7 (c) Anaerobic rostellates in the sediments of fast-flowing rivers ( Anaerolineae A one-dimensional distribution; Figure 7 (d) Bacteroidetes in sediments of fast-flowing rivers ( Bacteroidia The one-dimensional distribution of phosphorus was observed. Vertical distribution characteristics showed that the available phosphorus content at all sampling points initially increased and then decreased with increasing depth, but the specific distribution patterns differed significantly. In the overlying water layer (0-6 cm), the available phosphorus content increased significantly with depth, indicating a clear phosphorus deposition and enrichment process in the water. In the sedimentary layer (6-21 cm), the available phosphorus content in the sediments of fast-flowing rivers initially increased at a depth of 9-12 cm, then fluctuated and decreased. This may be related to the phosphorus fixation-release balance caused by the alkaline environment and high calcium content.

[0062] The bacterial community in fast-flowing river sediments was dominated by γ-Proteobacteria, with relatively small variations in their relative abundance, indicating a crucial role in the sediment ecosystem. Anaerobic Rodentia and Bacteroidetes showed good adaptation to the fast-flowing river sediments. Furthermore, the bacterial community structure was relatively stable vertically, with minimal variations in the relative abundance of the dominant classes, suggesting that the vertical influence of the environmental conditions in fast-flowing river sediments on the bacterial community may be relatively small.

[0063] Test Example 2

[0064] 1) Sediment pre-cultivation

[0065] In the middle and lower reaches of the Nantiao River in Hangzhou, Zhejiang Province, slow-flowing river sediments were selected as pre-culture sediments, and corresponding sediments and overlying water were collected in advance. The collected sediments were placed in sedimentation tanks and the corresponding overlying water was added for pre-culture for 14 days to simulate the sediment development process under natural conditions.

[0066] 2) Installation of the device

[0067] Select an in-situ detector with a tooth groove width of 1.5cm, install a shield and in-situ detector, and place the shield and in-situ detector in the sediment after step 1) and 14 days of culture in a vertically downward direction. Use the control panel to adjust the internal temperature of the shield to 25℃ and maintain it for 24 hours.

[0068] 3) In-situ sampler preprocessing

[0069] After completing step 2), slowly remove the shield and in-situ detector from the sediment in a vertically upward direction. Disassemble the in-situ detector from the shield. Use a knife to smooth the sediment in each set of grooves of the in-situ detector, removing excess sediment from the outside of each groove. Collect sediment from grooves at the same depth for microbial community analysis, setting up three parallel sets, each packaged in a 1.5 mL centrifuge tube. Wash the surface of the DGT membrane with deionized water to remove any adhering sediment particles. Carefully disassemble the housing of the in-situ detector and remove the DGT membrane. Place the DGT membrane on a clean acrylic plate. Use a clean knife to cut the DGT membrane into several small pieces according to the groove spacing, placing each piece in a 1.5 mL centrifuge tube. Add 2 mL of 0.5 mL of [unspecified ingredient] to the centrifuge tube. The DGT membrane was soaked in a sodium hydroxide solution of mol / L for 24 hours to elute the trace elements adsorbed on the surface of the membrane. The phosphorus content in the eluent was detected by ICP-MS. The effective phosphorus diffusion flux along the depth gradient of the sediment profile was calculated based on the area of ​​the DGT membrane cut and the time of deployment in the sediment.

[0070] Reference Figure 8 , Figure 8 This is a one-dimensional spatial distribution map of available phosphorus and bacterial communities in a slow-flowing river sediment profile with a resolution of 1.5 cm. Figure 8 (a) A one-dimensional distribution of available phosphorus content in sediment profiles and overlying water in slow-flowing rivers; Figure 8 (b) Gamma-Proteobacteria in sediments of slow-flowing rivers ( Gammaproteobacteria A one-dimensional distribution; Figure 8 (c) Anaerobic rostellates in slow-flowing river sediments ( Anaerolineae A one-dimensional distribution; Figure 8 (d) Bacteroidetes in sediments of slow-flowing rivers ( Bacteroidia The effective phosphorus content at each sampling point showed a one-dimensional distribution. Vertical distribution characteristics indicated that the effective phosphorus content initially increased and then decreased with increasing depth, but the specific distribution patterns varied significantly. In the overlying water layer (0-6 cm), the effective phosphorus content increased significantly with depth, indicating a clear phosphorus deposition and enrichment process in the water. In the sedimentary layer (6-21 cm), the effective phosphorus content was highest in slow-flowing river sediments at a depth of 12-15 cm, possibly related to anoxic reducing conditions and microbial activity.

[0071] The bacterial community structure in slow-flowing river sediments exhibits complex variations. The abundance of anaerobic ligamentous bacteria initially increases and then decreases with depth, while Bacteroidetes show higher abundance, reflecting the complexity of the slow-flowing river sediment environment. Environmental factors at different depths have a combined impact on bacterial community distribution. The overall available phosphorus content in slow-flowing river sediments is high, and hot zones exist. The initial increase followed by a decrease in the abundance of anaerobic ligamentous bacteria may provide an explanation for microbial-mediated phosphorus-iron cycling under anaerobic conditions.

[0072] Test Example 3

[0073] 1) Sediment pre-cultivation

[0074] In the lakes within the Zijingang Campus of Zhejiang University, still lake sediments were selected as pre-culture sediments, and corresponding sediments and overlying water were collected in advance. The collected sediments were placed in sedimentation tanks and the corresponding overlying water was added for pre-culture for 14 days to simulate the sediment development process under natural conditions.

[0075] 2) Installation of the device

[0076] Select an in-situ detector with a tooth groove width of 0.75cm, install a shield and in-situ detector, place the shield and in-situ detector in the sediment after step 1) and 14 days of culture in a vertically downward direction, operate the function panel, adjust the internal temperature of the shield to 25℃, and maintain it for 24 hours.

[0077] 3) In-situ sampler preprocessing

[0078] After completing step 2), slowly remove the shield and in-situ detector from the sediment in a vertically upward direction. Disassemble the in-situ detector from the shield. Use a knife to smooth the sediment in each set of grooves of the in-situ detector, removing excess sediment from the outside of each groove. Collect sediment from grooves at the same depth for microbial community analysis, setting up three parallel sets, each packaged in a 1.5 mL centrifuge tube. Wash the surface of the DGT membrane with deionized water to remove any adhering sediment particles. Carefully disassemble the housing of the in-situ detector and remove the DGT membrane. Place the DGT membrane on a clean acrylic plate. Use a clean knife to cut the DGT membrane into several small pieces according to the groove spacing, placing each piece in a 1.5 mL centrifuge tube. Add 2 mL of 0.5 mL of [unspecified ingredient] to the centrifuge tube. The DGT membrane was soaked in a sodium hydroxide solution of mol / L for 24 hours to elute the trace elements adsorbed on the surface of the membrane. The phosphorus content in the eluent was detected by ICP-MS. The effective phosphorus diffusion flux along the depth gradient of the sediment profile was calculated based on the area of ​​the DGT membrane cut and the time of deployment in the sediment.

[0079] Reference Figure 9 , Figure 9 This is a one-dimensional spatial distribution map of available phosphorus and bacterial communities in a still lake sediment profile with a resolution of 0.75 cm. Figure 9 (a) A one-dimensional distribution of available phosphorus content in sediment profiles of a quiescent lake and in the overlying water; Figure 9 (b) Gamma-Proteobacteria in quiescent lake sediments ( Gammaproteobacteria A one-dimensional distribution; Figure 9 (c) Anaerobic rostellates in quiescent lake sediments ( Anaerolineae A one-dimensional distribution; Figure 9(d) Bacteroidetes in quiescent lake sediments ( Bacteroidia The one-dimensional distribution of phosphorus was observed. Vertical distribution characteristics showed that the available phosphorus content at all sampling points initially increased and then decreased with increasing depth, but the specific distribution patterns differed significantly. In the overlying water layer (0-6 cm), the available phosphorus content increased significantly with depth, indicating a clear phosphorus deposition and enrichment process in the water. In the sedimentary layer (6-21 cm), the available phosphorus content in quiescent lake sediments was highest at a depth of 12-15 cm, possibly related to its higher clay content and neutral pH conditions.

[0080] The bacterial community structure of quiescent lake sediments varies significantly with depth. Anaerobic rostellates rise slightly with depth, while Bacteroidetes decrease. This variation indicates a significant vertical environmental gradient in quiescent lake sediments, which in turn influences bacterial community distribution.

[0081] Test Example 4

[0082] 1) DGT Imaging Analysis

[0083] During the sediment culture process in Test Examples 1-3, three additional sets of a simultaneous detection device for sediment micro-elements and microorganisms were deployed for in-situ chemical imaging of the sediments. Sediment particles adhering to the DGT membrane surface were cleaned with deionized water. The DGT membrane was carefully removed from the shell and placed in a pre-prepared molybdenum blue chromogenic solution for a colorimetric reaction. After soaking for 15 minutes, the membrane was removed and washed with deionized water to remove any remaining molybdenum blue chromogenic solution. The chromogenic DGT membrane was then placed in a scanner to acquire the image for subsequent quantitative analysis.

[0084] 2) Marking line drawing

[0085] Phosphorus standard solutions with concentrations of 0, 20, 50, 100, 200, 500, 750, 1000, and 2000 μg / L were prepared using phosphorus standard materials. Circular DGT membranes were placed in the P solutions and, after adsorption for 12 hours, were developed in molybdenum blue solution. The colored DGT membranes were immediately rinsed several times with deionized water at 4°C to remove residual colorant. They were then soaked in deionized water for another 5 minutes (to stop the color development reaction). The DGT membranes were then removed, wiped dry with filter paper, and placed on a scanner (face down). The scanner resolution was set to 1200 dpi. After obtaining the image, ImageJ software was used to convert the image to grayscale. The exponential function with the highest correlation was selected to fit the cumulative P amount per unit area on the membrane and its corresponding grayscale intensity. Figure 10 This is the standard curve (G(f)) of the cumulative amount per unit area of ​​the analyte (f) minus the gray value (G).

[0086] Reference Figure 11, Figure 11 This is a two-dimensional spatial distribution map of available phosphorus in sediment profiles from fast-flowing rivers, slow-flowing rivers, and quiescent lacustrine lakes. Fast-flowing river sediments exhibit strong spatial variability at depths of 0–3 cm, while showing relative uniformity at deeper layers. Slow-flowing river sediments generally have higher and more uniform available phosphorus content, but distinct hot zones are still visible at depths of 12–15 cm. Quiescent lacustrine sediments form large, continuous hot zones at depths of 12–15 cm. Therefore, fast-flowing rivers, influenced by strong currents, result in uneven distribution of available phosphorus at the surface; while slow-flowing river sediments and quiescent lacustrine sediments, due to their relatively stable aquatic environments, exhibit more continuous patterns of available phosphorus distribution.

[0087] In summary, enrichment zones of available phosphorus were observed in fast-flowing, slow-flowing, and quiescent lacustrine sediments at specific depths within the sedimentary layers. Subsequently, the available phosphorus content gradually decreased with increasing sedimentary depth. These results indicate that external water flow and differences in sediment grain size distribution are the main environmental factors contributing to the heterogeneous distribution of phosphorus in sediments. Furthermore, the redox gradients along depth in different sediments shape distinct microbial communities, thus significantly influencing the biogeochemical cycle of phosphorus.

[0088] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A device for simultaneous detection of micro-elements and microorganisms in sediment micro-domains, characterized in that, include, The shield (1) has a mounting hole (11) and a vent (12), and the shield (1) is equipped with a function panel (13) for adjusting the temperature inside the shield (1). An in-situ detector (2) is installed in a mounting hole (11) in a vertically downward direction. The in-situ detector (2) includes a housing (21) and a DGT membrane (22). A plurality of horizontal grooves (213) are provided on one side of the housing (21). The plurality of grooves (213) are evenly arranged in a vertical direction on one side of the housing (21). The groove openings of the grooves (213) are facing upward. The DGT membrane (22) is installed in the housing (21). A detection window (214) is provided on the side of the housing (21) away from the grooves (213).

2. The device for simultaneous detection of micro-elements and microorganisms in sediments according to claim 1, characterized in that, The shield (1) is made of stainless steel. The inner wall of the shield (1) is provided with a heating wire (14). The function panel (13) is used to control the temperature of the heating wire (14).

3. The device for simultaneous detection of micro-elements and microorganisms in sediments according to claim 1, characterized in that, The depth of the tooth groove (213) is 0.5cm, and the width of the tooth groove (213) is 0.75-3cm.

4. The device for simultaneous detection of micro-elements and microorganisms in sediments 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). The edges of the front plate (211) and the rear plate (212) are fixedly connected by bolts (216). The tooth groove (213) is located on the side of the rear plate (212) away from the front plate (211), and the detection window (214) is located on the front plate (211).

5. The device for simultaneous detection of micro-elements and microorganisms in sediments 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 tightly attached to the front plate (211) and the rear plate (212).

6. The device for simultaneous detection of micro-elements and microorganisms in sediments according to claim 4, characterized in that, The shell (21) is made of plastic.

7. A detection method using the simultaneous detection device for micro-elements and microorganisms in sediments as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Install the shield (1) and the in-situ detector (2), and insert them into the sediment to be detected in a vertically downward direction. Operate the function panel (13) to adjust the temperature inside the shield (1) to 25°C and keep it for 24 hours. S2. Slowly remove the shield (1) and the in-situ detector (2) from the sediment in a vertically upward direction. Remove the in-situ detector (2) from the shield (1), remove the excess sediment outside each set of tooth grooves (213) of the in-situ detector (2), and wash the sediment particles adhering to the surface of the DGT membrane (22) with deionized water. S3. Take out the sediment in each set of tooth grooves (213) and seal it in a centrifuge tube for later use; 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 groove (213) and place them in centrifuge tubes respectively. Elute the trace elements adsorbed on the surface of the unit module to obtain the eluent. Detect the phosphorus content in the eluent. 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 of placement in the sediment. Alternatively, disassemble the housing (21) of the in-situ detector (2) and remove the DGT membrane (22). Place the DGT membrane (22) without cutting it in a pre-prepared molybdenum blue colorant solution for color development. After soaking for 15 minutes, remove it and wash away the molybdenum blue colorant solution remaining on the surface of the DGT membrane (22) with deionized water. Then place the color-developed DGT membrane (22) in a scanner to obtain the color-developed image.

8. The detection method according to claim 7, characterized in that, The method for removing 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, the eluent is obtained, and the phosphorus content in the eluent is detected by ICP-MS.

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