An in-situ monitoring system for deep-sea mining plume diffusion and its monitoring method

Abstract

The present invention provides an in-situ monitoring system for deep-sea mining plume diffusion and its monitoring method, which includes a monitoring central node device and a portable monitoring node device, and can conduct in-situ monitoring of mining plume diffusion through monitoring networking. It can conduct in-situ monitoring of sediment plumes, which is of great significance for the evaluation of the impact of mining on the environment, fills the gap in the in-situ means for effectively locating the three-dimensional spatial distribution of plumes, and meets the monitoring requirements for the deposition thickness of plume particles. By constructing the relationship between the changes in environmental elements affected by the plume, it fills the gap in the all-element monitoring of the environmental impact of the plume. Establishing the relationship between plume diffusion and changes in environmental elements helps in the quantitative evaluation of the impact of mining on the environment. It can monitor and analyze the physical and chemical processes and the impact on biodiversity in the environment around mining activities. The observed data can provide effective and real parameters for plume numerical simulation, provide data support for environmental parameter prediction and prediction of the impact on benthic biological groups, and obtain the three-dimensional spatial distribution of the plume.

Description

Technical Field

[0001] The present invention relates to the technical fields of subsea exploration and marine engineering geology. Specifically, it particularly relates to an in-situ monitoring system for deep-sea mining plume diffusion and a monitoring method thereof. Background Art

[0002] At different stages of deep-sea seabed resource development, the marine environment will be affected. The mining vehicle removes solid minerals on the seabed, and megabenthos will be directly affected by the operation of the mining vehicle; the stirred sediment particles diffuse with the bottom current to form a plume. The particulate matter adheres to the surface of large organisms and will block their respiratory systems, and toxic substances such as heavy metals will cause poisoning to aquatic organisms; the fragile chemical environment at the sediment-water interface is disrupted, and the interstitial water characterized by ionic state mixes into the near-bottom water and widely diffuses, having a long-term impact on the functions of the seabed ecosystem. In addition, light pollution and noise pollution will be generated during long-term mining operations. A large amount of waste generated during the processing of seabed minerals is discarded in the ocean, and pollutants generated by a large number of ships engaged in the transportation industry are directly discharged into the sea, which will cause pollution to the deep-sea environment. Since deep-sea resources are usually located in areas with relatively complex geological structures, significant and concentrated fault activities, geological disasters such as earthquakes and submarine landslides are likely to be induced in the later stage of deep-sea mining. These links in deep-sea resource exploitation will all have an impact on the deep-sea ecosystem. If commercial exploitation of deep-sea mineral resources is to be carried out, it is necessary to evaluate the environmental impact of deep-sea mining. Plume diffusion environmental monitoring is an important means to evaluate the degree of mining environmental impact at present.

[0003] At present, the commercial-scale mining system has not been finalized, and the intensity of its environmental disturbance cannot be judged, and the degree of environmental impact of commercial-scale mining is not clear. There is a lack of research on the resedimentation diffusion of deep-sea plumes and the impact on the deep-sea bottom environment and biological groups. There are still controversies about the severity and spatial scale of the plumes formed by deep-sea mining, and the response mechanism of plume disturbance resedimentation is not yet clear. At present, the in-situ monitoring means for deep-sea mining plumes have incomplete and inaccurate evaluation parameters, and cannot conduct long-term in-situ monitoring of the diffusion of seabed mining plumes. The technical method system for monitoring and evaluating the environmental impact of deep-sea mining has not been established, and it cannot provide technical and data support for the environmental impact assessment of commercial exploitation. There is an urgent need for an in-situ monitoring system for deep-sea mining plume diffusion. Summary of the Invention

[0004] In order to make up for the deficiencies of the prior art, the present invention provides an in-situ monitoring system for deep-sea mining plume diffusion and a monitoring method thereof. The monitoring system includes a monitoring center node device and a portable monitoring node device, and can conduct in-situ monitoring of mining plume diffusion through monitoring networking.

[0005] The present invention is realized through the following technical solutions: An in-situ monitoring system for deep-sea mining plume diffusion, comprising a central monitoring node device, three Type-I portable monitoring node devices, three Type-II portable monitoring node devices, and a sea-surface monitoring buoy.

[0006] The central monitoring node device includes an instrument frame, which is divided into upper, middle, and lower parts. One end of a first Kevlar cable is connected to the center position of the upper frame of the instrument frame, and the other end of the first Kevlar cable is connected to a deployment and recovery pressure-resistant buoy. A floating material is installed around the outside of the upper frame of the instrument frame, and an acoustic release, an Iridium beacon, an optical beacon, and an acoustic communication machine are installed on the top of the floating material. Four groups of first subsea pressure-resistant buoys are installed at the four corners inside the upper frame of the instrument frame. A master control cabin, a dissolved oxygen sensor, a binocular camera control cabin, and a CTD sensor are placed clockwise inside the upper frame of the instrument frame. A plume particle monitoring device, a plume environment image monitoring device, and a plume re-deposition thickness monitoring device are installed clockwise around the bottom periphery of the upper frame of the instrument frame. Four groups of seawater dissolved oxygen batteries are placed inside the middle frame of the instrument frame. The bottom frame of the instrument frame is four support legs, and a bottom-mounted counterweight tray is installed at the bottom end of each leg through a counterweight decoupler.

[0007] The Type-I portable monitoring node device includes a recovery beacon and a sediment trap. The recovery beacon and the sediment trap are connected by a second Kevlar cable. Four second glass buoys are installed inside the recovery beacon, and a second acoustic communication machine is installed at the bottom of the recovery beacon. Three plume three-dimensional diffusion monitoring systems are installed at equal intervals on the second Kevlar cable. A sediment trap battery compartment is installed at the bottom of the sediment trap. The plume three-dimensional diffusion monitoring system includes a sensor outer compartment and a watertight connector connected to one end thereof. A circuit board and a collector are installed inside the sensor outer compartment, and wiring electrodes are installed inside the watertight connector. The wiring electrodes are four platinum electrodes evenly distributed in position. The ratio electrode and the natural potential electrode are both made of titanium alloy-graphene material, and the redox electrode is a platinum electrode. Each sub-node realizes sequential acquisition of electrical parameters through one AD acquisition.

[0008] The Type-II portable monitoring node device includes a third glass buoy and a node device frame. The third glass buoy and the node device frame are connected by a third Kevlar cable. A fourth pressure-resistant buoy is installed on the upper part of the node device frame, and a third acoustic communicator, an electrochemical sensor, and a Type-II monitoring node control cabin are installed inside the node device frame.

[0009] As a preferred solution, the plume re-deposition thickness monitoring device includes a rotating motor cabin and an optical measurement cabin.

[0010] As a preferred solution, the plume environment image monitoring device includes an illumination unit and a binocular camera.

[0011] As a preferred solution, the plume electrochemical sensor includes a sensor housing. Electrical sensor connectors and electrochemical sensor data connectors are respectively installed at the left and right ends of the sensor housing. An electrochemical sensor electrode, an electrochemical sensor circuit board, and an electrochemical sensor data collector are installed inside the sensor housing. The electrochemical sensor electrode is electrically connected to the electrical sensor connector, and the electrochemical sensor data connector is electrically connected to the electrochemical sensor data collector.

[0012] A monitoring method for a deep-sea mining plume diffusion in-situ monitoring system, characterized in that it specifically includes the following steps

[0013] Step S1, platform deployment: The central monitoring node device is deployed through the ship's cable and arranged outside the 50 m range of the mining vehicle in the actual mining operation area;

[0014] Step S2, determine the flow direction: According to the driving distance of the mining vehicle, determine the plume flow direction position;

[0015] Step S3, node layout: First, deploy the central monitoring node device around the mining vehicle, deploy the type I portable monitoring node device on the back of the mining vehicle plume, and then deploy the type I portable monitoring node device and the type II portable monitoring node device every 1 km along both sides of the mining vehicle to cover the plume deployment range; The deployment and recovery steps of the central monitoring node device are:

[0016] Step S3-1, cable-lowered deployment: Lower it through the geological compass of the mother ship, hook the cable with an acoustic release, then lower it to the bottom, and then the acoustic release unhooks;

[0017] Step S3-2, the equipment is powered by a seawater dissolved oxygen battery, and the lithium battery carried by the equipment is used as a backup. The plume particle monitoring system, plume re-deposition thickness monitoring system, plume environment image monitoring device, and plume biochemical environment monitoring device carried by the central monitoring node work continuously without interruption, collect and store data at any time, and perform wireless transmission;

[0018] Step S4, networking observation, according to the traveling direction and working model of the mining vehicle, the central monitoring node device, the type I portable monitoring node device, and the type II portable monitoring node device continuously perform networking monitoring, converge the data to the total control, and transmit the data acoustically;

[0019] Step S5, data analysis:

[0020] Analyze according to the uploaded data. The plume three-dimensional diffusion in-situ monitoring sensor carried by the type I portable monitoring node device jointly inverses the turbidity using natural potential, redox potential, and resistivity;

[0021] The inversion formula is:

[0022]

[0023] where ρ is the resistivity (Ω·m), S is the salinity (‰), T is the temperature (K), s is the type of suspended particulate matter, c is the concentration of seawater suspended particulate matter (g·L -1 ), and k(S,T,s) is to determine the salinity S, temperature T, and plume particle type x , and the rate of change of resistivity ρ with plume concentration c. SP is the spontaneous potential value (mV), S is the salinity, T is the temperature (K), x is the plume particle type, Z is the water level height (cm) relative to the reference electrode, and c is the concentration of seawater suspended particulate matter (g·L -1 ). Eh is the redox potential (mV), S is the salinity (‰), T is the temperature (K), x is the plume particle type, pH is the acidity and alkalinity of the solution, DO is the dissolved oxygen content of the solution (mg·L -1 ), c is the concentration of seawater suspended particulate matter (g·L -1 ), j (S,T,s,pH,DO) is to determine the salinity S, temperature T, plume particle type x , solution pH, and dissolved oxygen content DO of the solution, and the rate of change of redox potential Eh with plume concentration c .

[0024] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects compared with the prior art:

[0025] 1. The present invention is an in-situ monitoring system for the diffusion of submarine mining plumes. The central monitoring node is powered by a seawater dissolved oxygen battery and a built-in energy storage battery, which can conduct in-situ monitoring of sediment plumes (high-resolution monitoring of particles in the plume, three-dimensional diffusion monitoring of the plume, monitoring of the re-deposition thickness and deposition amount of the plume, which is of great significance for the evaluation of the mining environment impact, fills the gap in the in-situ means for effectively positioning the three-dimensional spatial distribution of the plume, can meet the monitoring requirements of the deposition thickness of plume particles, is more comprehensive and has higher resolution compared with the prior art).

[0026] 2. The present invention is an in-situ monitoring means for the environmental impact of plumes, which can construct the relationship between the changes in environmental elements affected by plumes, filling the gap in the all-element monitoring of the environmental impact of plumes. The changes in environmental elements are the direct manifestation of the environmental impact of sediment plumes. The migration and diffusion of sediment plumes will change parameters such as water temperature, salinity, Eh, pH, and Do. Establishing the relationship between plume diffusion and changes in environmental elements is helpful for the quantitative evaluation of mining environmental impact. The sensors involved in the present invention can collect long-term in-situ observation data to meet the requirements of long-term in-situ observation in the deep sea.

[0027] 3. The present invention is rationally designed. Relying on the central monitoring node device and the portable monitoring node device, the deployment and recovery method is simple and effective. It realizes comprehensive and systematic in-situ monitoring and environmental impact assessment of the mining environment, can monitor and analyze the physical and chemical processes and the impact on biodiversity in the environment around mining activities. The observed data can provide effective and real parameters for plume numerical simulation, can provide data support for environmental parameter prediction and the prediction of the impact on benthic biological groups, and can obtain the three-dimensional spatial distribution of the plume.

[0028] The additional aspects and advantages of the present invention will become apparent in the following description section or be learned through the practice of the present invention. Brief Description of the Drawings

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0030] Figure 1 is the overall structure diagram of the central monitoring node device;

[0031] Figure 2 is the internal structure diagram of the central monitoring node device;

[0032] Figure 3 is the platform sectional view of the central monitoring node device

[0033] Figure 4 is the schematic diagram of the Type I portable monitoring node device;

[0034] Figure 5 is the schematic diagram of the in-situ monitoring sensor for three-dimensional diffusion of the plume;

[0035] Figure 6 is the sectional schematic diagram of the in-situ monitoring sensor for three-dimensional diffusion of the plume;

[0036] Figure 7 is the schematic diagram of the Type II portable monitoring node device;

[0037] Figure 8 is the sectional schematic diagram of the electrochemical sensor;

[0038] Figure 9 is the schematic diagram of the deployment operation of the central monitoring node;

[0039] Figure 10 is the working mode diagram of the in-situ monitoring system for deep-sea mining plume;

[0040] Among them, Figures 1 to 10 the corresponding relationship between the marks and the components is:

[0041] 1 - First Kevlar cable, 2 - First subsea pressure-resistant buoy, 3 - Acoustic release, 4 - Floating body material, 5 - Instrument frame, 6 - Plume sediment thickness monitoring device, 7 - Plume environment image monitoring device, 8 - Seawater dissolved oxygen battery, 9 - Counterweight decoupler, 10 - First bottom counterweight tray, 11 - Iridium beacon, 12 - Optical beacon, 13 - Acoustic communication device, 14 - Plume particle monitoring device, 15 - Total control cabin, 16 - Dissolved oxygen sensor, 17 - Binocular camera control cabin, 18 - CTD sensor, 19 - Recovery beacon, 20 - Second subsea pressure-resistant buoy, 21 - Second acoustic communication device, 22 - Second Kevlar cable, 23 - Plume three-dimensional diffusion monitoring device, 24 - Sediment trap, 25 - Sediment trap battery compartment, 26 - Second bottom decoupling counterweight tray, 27 - Watertight connector, 28 - Sensor outer compartment, 29 - Wiring channel, 30 - Circuit board, 31 - Collector, 32 - Third pressure-resistant buoy, 33 - Third Kevlar cable, 34 - Fourth pressure-resistant buoy, 35 - Third acoustic communicator, 36 - Electrochemical sensor, 37 - Type-II monitoring node control cabin, 38 - Electrical sensor connector, 39 - Sensor housing, 40 - Electrochemical sensor electrode, 41 - Electrochemical sensor circuit board, 42 - Electrochemical sensor data collector, 43 - Electrochemical sensor data connector, 44 - Deployment and recovery pressure-resistant buoy. Detailed implementation mode

[0042] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention will be further described in detail below with reference to the drawings and specific implementation modes. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0043] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0044] The following combines Figures 1 to 10 to specifically describe the in-situ monitoring system for deep-sea mining plume diffusion and its monitoring method in the embodiments of the present invention.

[0045] As Figures 1 to 7 shown, the present invention provides an in-situ monitoring system for deep-sea mining plume diffusion, which is characterized by including a central monitoring node device, 3 Type-I portable monitoring node devices, 3 Type-II portable monitoring node devices, and a sea surface monitoring buoy; the Type-I and Type-II monitoring nodes are arranged in a hexagon around the central monitoring node, and the sea surface monitoring buoy is connected on the sea surface;

[0046] As Figure 1As shown in the figure, the central monitoring node device includes an instrument frame 5. The instrument frame 5 is divided into upper, middle, and lower parts. One end of a first Kevlar cable 1 is connected to the center position of the upper frame of the instrument frame 5, and the other end of the first Kevlar cable 1 is connected to a deployed and recovered pressure-resistant floating ball 44. A floating material 4 is installed around the outside of the upper frame of the instrument frame 5. An acoustic release 3, an Iridium beacon 11, an optical beacon 12, and an acoustic communication machine 13 are installed on the top of the floating material 4. Four groups of first subsea pressure-resistant floating balls 2 are installed at the four corners inside the upper frame of the instrument frame 5. A master control cabin 15, a dissolved oxygen sensor 16, a binocular camera control cabin 17, and a CTD sensor 18 are placed clockwise inside the upper frame of the instrument frame 5. A plume particle monitoring device 14, a plume environment image monitoring device 7, and a plume re-deposition thickness monitoring device 6 are installed clockwise around the bottom periphery of the upper frame of the instrument frame 5; Four groups of seawater dissolved oxygen batteries 8 are placed inside the middle frame of the instrument frame 5. The seawater dissolved oxygen battery 8 is composed of a positive electrode material of carbon fiber and a negative electrode material of magnesium alloy rod. Electric energy is generated by the reaction between the positive and negative electrodes. A total of 8 single-module batteries are required for the system, which are connected to the energy storage battery in parallel, and the monitoring platform equipment is powered by the discharge of the energy storage battery. The bottom frame of the instrument frame 5 is four support legs, and a bottom weight tray 10 is installed at the bottom end through a weight decoupling device 9 respectively; The plume re-deposition thickness monitoring device 6 includes a rotating motor cabin and an optical measurement cabin. The plume environment image monitoring device 7 includes an illumination unit and a binocular camera. Each device inside the central monitoring node device is set with a hollow and non-closed structure clockwise. Each device has the working conditions of withstanding pressure on the seabed, and the equipment is intensively installed, making reasonable use of space. It can carry a variety of devices, and the instrument equipment does not interfere with each other and cooperates with each other.

[0047] As Figure 4 shown in the figure, the type-I portable monitoring node device includes a recovery beacon 19 and a sediment trap 24. The recovery beacon 19 and the sediment trap 24 are connected by a second Kevlar cable 22. Four second glass floating balls 20 are installed inside the recovery beacon 19. A second acoustic communication machine 21 is installed at the bottom of the recovery beacon 19. Three plume three-dimensional diffusion monitoring systems 23 are installed at equal intervals on the second Kevlar cable 22. A sediment trap battery compartment 25 is installed at the bottom of the sediment trap 24.

[0048] As Figure 5 , as shown in Figure 6, the plume three-dimensional diffusion monitoring system 23 includes a sensor outer compartment 28 and a watertight connector 27 connected to one end of it. A circuit board 30 and a collector 31 are installed inside the sensor outer compartment 28. A wiring electrode 29 is installed inside the watertight connector 27. The wiring electrode 29 is four platinum electrodes evenly distributed in position. The ratio electrode and the natural potential electrode are both made of titanium alloy-graphene material, and the redox electrode is a platinum electrode. Each sub-node realizes the sequential acquisition of electrical parameters through one AD acquisition;

[0049] The electro-optical turbidity inversion technology involved in the plume three-dimensional diffusion monitoring device has been well verified by the electro-optical - turbidity inversion model constructed through artificial neural network technology. The monitoring range of the plume three-dimensional diffusion monitoring system is 30 m, and the resolution is 1 m. The plume three-dimensional diffusion monitoring device adopts the design of electro-optical monitoring sub-nodes to achieve data communication and reliable connection, and adopts the technology of constructing an electro-optical turbidity inversion model based on artificial neural network technology.

[0050] As Figure 7 shown, the Type II portable monitoring node device adopts a mooring buoy design and can receive instructions to float to the surface, with each part working independently. The Type II portable monitoring node device includes a third glass float 32 and a node device frame. The third glass float 32 and the node device frame are connected by a third Kevlar cable 33. The upper part of the node device frame is equipped with a fourth pressure-resistant float 34. Inside the node device frame, there are a third acoustic communicator 35, an electrochemical sensor 36, and a Type II monitoring node control bin 37;

[0051] As Figure 8 shown, the plume electrochemical sensor 36 mainly has an independently developed integrated electrochemical parameter monitoring system to achieve in-situ long-term monitoring of pH, Eh, and conductivity. The Ti / ternary nickel cobalt manganese oxide modification technology for the pH electrode, the preparation technology of the anti-polarization solid-state Ag / AgCl porous electrode, and the preparation technology of the Ti3Pt-coated electrode for the oxidation-reduction potential are developed; the plume electrochemical sensor 36 includes a sensor housing 39. At the left and right ends of the sensor housing 39, there are respectively an electrical sensor connector 38 and an electrochemical sensor data connector 43. Inside the sensor housing 39, there are an electrochemical sensor electrode 40, an electrochemical sensor circuit board 41, and an electrochemical sensor data collector 42. The electrochemical sensor electrode 40 is electrically connected to the electrical sensor connector 38, and the electrochemical sensor data connector 43 is electrically connected to the electrochemical sensor data collector 42.

[0052] The master control system collects sensor data through analog, digital and other interfaces, completes data acquisition, transmission, storage, and power supply control of all sensors, and adopts key technologies such as time synchronization technology and low-power stable operation technology. Based on the underwater acoustic communication machine, the communication and control between the surface communication buoy - central monitoring node - Type I portable node are realized, and the acoustic communication machines of the surface communication buoy and the central monitoring node are in "dual backup".

[0053] A monitoring method for a deep-sea mining plume diffusion in-situ monitoring system specifically includes the following steps:

[0054] Step S1, platform deployment: The central monitoring node device is deployed through the ship's cable and arranged outside the 50 m range of the mining vehicle in the actual mining operation area. This distance avoids disturbing the mining vehicle and affecting the mining operation, and determines the operation point in the mining vehicle operation area;

[0055] Step S2, Determine the flow direction: Based on the driving distance of the mining vehicle, determine the flow direction position of the plume to facilitate layout.

[0056] Step S3, Node layout: First, deploy the central monitoring node device around the mining vehicle, deploy the Type-I portable monitoring node device on the back of the plume of the mining vehicle, and then deploy the Type-I portable monitoring node device and the Type-II portable monitoring node device every 1 km along both sides of the mining vehicle. The Type-I monitoring nodes and the Type-II monitoring nodes are arranged in a hexagon as a whole around the central node, covering the plume deployment range.

[0057] As Figure 9 shown, the central monitoring node device is equipped with functional instrument and equipment such as in-situ monitoring instrument and equipment, seawater battery, total control system, acoustic communication machine, etc., and works in the mode of "cabled lowering - automatic monitoring - self-floating recovery".

[0058] As Figure 10 shown, the portable node transmits data to the total control of the monitoring platform through underwater acoustic communication. The latter transmits the data of multiple elements aggregated on the seabed to the surface communication buoy through underwater acoustic communication equipment, and finally the communication buoy transmits the data to the shore-based receiving and processing system (buoy receiving shore station) through satellite communication equipment. The specific steps for deploying and recovering the central node monitoring device are as follows:

[0059] Step S3-1, Cabled lowering: Lower it through the geological compass of the mother ship, hook the cable with the help of the acoustic release 3, then lower it to the bottom, and then the acoustic release 3 unhooks.

[0060] Step S3-2, The equipment is powered by the seawater dissolved oxygen battery 8, and the lithium battery carried by the equipment is used as a backup. The plume particle monitoring system, plume redeposition thickness monitoring system, plume environmental image monitoring device, and plume biochemical environment monitoring device carried by the central monitoring node work continuously without interruption, collect and store data at any time, and perform wireless transmission.

[0061] Step S4, Networked observation: According to the traveling direction and working model of the mining vehicle, the central monitoring node device, the Type-I portable monitoring node device, and the Type-II portable monitoring node device continuously perform networked monitoring. The Type-I and Type-II portable nodes are arranged in a hexagon as a whole around the central node, converge the data to the total control, and transmit the data acoustically.

[0062] The data transmission mode of the in-situ monitoring system for deep-sea mining plume is that the total monitoring control system includes the monitoring platform and the total control within the portable node. It collects sensor data through analog, digital and other interfaces, and completes the data collection, transmission, storage and power supply control of all sensors and portable nodes. The portable node transmits data to the total control of the monitoring platform through underwater acoustic communication. The latter transmits the data of multiple elements aggregated at the seabed to the surface communication buoy through underwater acoustic communication equipment. Finally, the communication buoy transmits the data to the shore-based receiving and processing system (buoy receiving shore station) through satellite communication equipment.

[0063] In the laboratory and overtime unit, and at the user end, an instruction is sent and received through an acoustic release device, and then the throw-off counterweight is discarded, which disconnects the throw-off counterweight from the central monitoring node device. The buoyancy of the central monitoring node is greater than the gravity, and then the equipment starts to slowly float up and floats to the water surface for equipment recovery.

[0064] The relevant relationship of the working mode of the in-situ monitoring system for deep-sea mining plume is that the total control system of the central monitoring node is responsible for the power supply, communication and control of the monitoring equipment, and all equipment is connected to this system. In the type-I portable monitoring node, the sediment trap works independently, and the plume three-dimensional diffusion monitoring system, communication system, etc. are connected to the node total control; in the type-II monitoring node, the sensors work independently without overall control.

[0065] The working mode of the in-situ monitoring system for deep-sea mining plume is to study the safe and reliable placement technology of the seabed monitoring platform, portable nodes and surface communication buoys and the underwater high-precision positioning technology, and build a seabed monitoring network in the monitoring area; using the seabed mining disturbance test equipment as the disturbance source, carry out in-situ long-term monitoring, and the portable monitoring nodes are respectively arranged at the front and rear of the mining plume disturbance, so as to monitor the three-dimensional diffusion of the plume in all directions and all spaces.

[0066] Step S5, data analysis:

[0067] Analyze according to the uploaded data. The plume three-dimensional diffusion in-situ monitoring sensor carried by the type-I portable monitoring node device jointly inverses turbidity using natural potential, redox potential and resistivity.

[0068] The inversion formula is:

[0069]

[0070] Where ρ is the resistivity (Ω·m), S is the salinity (‰), T is the temperature (K), s is the type of suspended particulate matter, c is the concentration of seawater suspended particulate matter (g·L -1 )), k(S,T,s) is to determine the salinity S, temperature T, and plume particle type x, the rate of change of resistivity ρ with plume concentration c. SP is the natural potential value (mV), S is the salinity, T is the temperature (K), x is the type of plume particles, Z is the water level height relative to the reference electrode (cm), and c is the concentration of suspended particles in seawater (g·L -1 ). Eh is the redox potential (mV), S is the salinity (‰), T is the temperature (K), x is the type of plume particles, pH is the acidity and alkalinity of the solution, and DO is the dissolved oxygen content of the solution (mg·L -1 ), c is the concentration of suspended particles in seawater (g·L -1 )、 j (S,T,s,pH,DO) is used to determine salinity S, temperature T, plume particle type x , solution pH, solution dissolved oxygen content DO, redox potential Eh with plume concentration c According to the physical and chemical environment of the plume and the corresponding seabed sediment type, relevant adjustment coefficients can be made to obtain the relevant plume concentration.

[0071] In the description of the present invention, the term "plurality" refers to two or more than two. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention; the terms "connection", "installation", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0073] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An in-situ monitoring system for deep-sea mining plume diffusion, characterized in that, It includes a central monitoring node device, 3 Type-I portable monitoring node devices, 3 Type-II portable monitoring node devices, and a sea surface monitoring buoy; The central monitoring node device includes an instrument frame, which is divided into upper, middle, and lower parts. One end of a first Kevlar cable is connected to the center position of the upper frame of the instrument frame, and the other end of the first Kevlar cable is connected to a deployment and recovery pressure-resistant buoy. A floating material is installed around the outside of the upper frame of the instrument frame, and an acoustic release, an Iridium beacon, an optical beacon, and an acoustic communication machine are installed on the top of the floating material. Four groups of first subsea pressure-resistant buoys are installed at the four corners inside the upper frame of the instrument frame. The main control cabin, dissolved oxygen sensor, binocular camera control cabin, and CTD sensor are placed clockwise inside the upper frame of the instrument frame. A plume particle monitoring device, a plume environment image monitoring device, and a plume redeposition thickness monitoring device are installed clockwise around the bottom periphery of the upper frame of the instrument frame; Four groups of seawater dissolved oxygen batteries are placed inside the middle frame of the instrument frame. The bottom frame of the instrument frame is four support legs, and a bottom weight tray is installed at the bottom end of each support leg through a weight decoupling device; The Type-I portable monitoring node device includes a recovery beacon and a sediment trap. The recovery beacon and the sediment trap are connected by a second Kevlar cable. Four second glass floats are installed inside the recovery beacon, and a second acoustic communication machine is installed at the bottom of the recovery beacon. Three plume three-dimensional diffusion monitoring systems are installed at equal intervals on the second Kevlar cable. A sediment trap battery compartment is installed at the bottom of the sediment trap. The plume three-dimensional diffusion monitoring system includes a sensor outer compartment and a watertight connector connected to one end of the sensor outer compartment. A circuit board and a collector are installed inside the sensor outer compartment, and wiring electrodes are installed inside the watertight connector. The wiring electrodes are four platinum electrodes evenly distributed in position. The ratio electrode and the natural potential electrode are both made of titanium alloy-graphene material, and the redox electrode is a platinum electrode. Each sub-node realizes sequential acquisition of electrical parameters through one AD acquisition; The Type-II portable monitoring node device includes a third glass float and a node device frame. The third glass float and the node device frame are connected by a third Kevlar cable. A fourth pressure-resistant buoy is installed on the upper part of the node device frame, and a third acoustic communicator, an electrochemical sensor, and a Type-II monitoring node control cabin are installed inside the node device frame.

2. The in-situ monitoring system for deep-sea mining plume diffusion according to claim 1, characterized in that ,The plume redeposition thickness monitoring device includes a rotary motor cabin and an optical measurement cabin.

3. The in-situ monitoring system for deep-sea mining plume diffusion according to claim 1, characterized in that ,The plume environment image monitoring device includes an illumination unit and a binocular camera.

4. The in-situ monitoring system for deep-sea mining plume diffusion according to claim 1, characterized in that ,The electrochemical sensor includes a sensor housing. Electrical sensor connectors and electrochemical sensor data connectors are respectively installed at the left and right ends of the sensor housing. An electrochemical sensor electrode, an electrochemical sensor circuit board, and an electrochemical sensor data collector are installed inside the sensor housing. The electrochemical sensor electrode is electrically connected to the electrical sensor connector, and the electrochemical sensor data connector is electrically connected to the electrochemical sensor data collector.

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