39 results about "Ocean sediment" patented technology

The invention provides a biochar repairing agent for marine sediments and a preparation method of the biochar repairing agent, and belongs to the technical field of repairing agents. The preparation method comprises the following steps: carbonizing straws, modifying by phosphoric acid and concentrated nitric acid, depositing ferroferric oxide-titanium dioxide, loading UiO-66-(COOH) 2 on the surface, coupling cyclodextrin-MOF and chitosan, crosslinking, performing magnet separation, washing and drying to obtain the biochar repairing agent for the marine sediments. The biochar repairing agent for the marine sediments prepared by the invention has a relatively large specific surface area and a plurality of coordination groups, can better fix heavy metal ions in the marine sediments, also has a photocatalytic degradation effect on organic pollutants, and is good in mechanical strength, easy to store and transport, safe, environment-friendly and easy to separate; wide application prospects are realized.

The invention discloses a marine fungus fusarium keratinoides and application thereof. The fusarium keratinoides capable of efficiently producing the perindoprine is screened from marine sediments, and the content of the produced perindoprine can reach 561.7 mu g / L after the fusarium keratinoides is fermented in a GPY liquid culture medium, so that possibility and a foundation are provided for breeding strains suitable for industrial large-scale production of the perindoprine in the future; mass spectrum, hydrogen spectrum and carbon spectrum data of the separated perindoprine are completely consistent with perindoprine data reported in literatures.

The invention discloses an in-situ suspended sediment concentration and flux prediction system based on conductivity data, and relates to the technical field of marine environment in-situ monitoring, the in-situ suspended sediment concentration and flux prediction system comprises a data processing and visualization platform, the data processing and visualization platform is in communication connection with the following modules: a data acquisition module, a data processing module, a data processing module and a data processing module, the method is used for extracting multi-dimensional water body data collected in an in-situ environment from a database. According to the method, a continuous vertical concentration-flow velocity matrix is generated through coupling corrected suspended sediment concentration data and flow velocity data, a flux prediction model is established in combination with historical data, a nonlinear relationship between sediment transportation flux and flow velocity-concentration is analyzed, and a random forest algorithm is adopted to determine the flow velocity-concentration of the sediment. The flow velocity, the conductivity interval depth and the corrected suspended sediment concentration serve as input variables, a sediment flux prediction value is output, static and dynamic comprehensive prediction of sediment fluxes at different moments and at different positions is achieved, and a quantitative analysis tool is provided for ocean sediment dynamic research and mineral environment evaluation.

The invention discloses a marine sediment heavy metal extraction device which comprises an extraction tank, the side end of the upper portion of the extraction tank is connected with a feeding pipe, a feeding hopper is arranged above the other side of the feeding pipe, the feeding pipe and the feeding hopper are connected through a support, and a gap is kept between an outlet and an inlet of the feeding pipe and the feeding hopper; a screening mechanism is arranged at the top of the extraction pipe and comprises a rotating shaft and a plurality of screening assemblies distributed on the rotating shaft, and when one screening assembly rotates to the gap, the feeding hopper, the screening assemblies and the feeding pipe form a closed and coherent channel; according to the device, high efficiency, automation and cleanness of extraction of the heavy metals in the marine sediments are realized through innovative dynamic sealing sieving, spiral stirring-filter pressing cooperation, intelligent temperature control separation and a modular absorption system.

The invention belongs to the field of ocean geophysical exploration, and particularly provides a device and a method for monitoring migration of CO2 in sediment based on a time domain reflectometry, the monitoring device comprises a reaction kettle, a vacuumizing and saturation system, a supercritical carbon dioxide preparation and injection system, a temperature control system, a dielectric constant test control system and a data acquisition and processing system; the dielectric constant test control system comprises a time domain reflection tester and a time domain reflection sensor assembly, wherein the time domain reflection sensor assembly comprises a plurality of axial time domain reflection sensors inserted from the bottom of the reaction kettle and a plurality of radial time domain reflection sensors inserted from the side surface of the reaction kettle. According to the device and the method, anisotropic dynamic monitoring of the continuous migration process of supercritical CO2 in the ocean sediment can be realized, and combined characterization of CO2 saturation and CO2 plume front migration dynamics in the sediment sample in the CO2 migration process can be realized, so that accurate evaluation of the storage efficiency and leakage risk of CO2 in the ocean sediment is realized, the monitoring effect is good, and the operation is simple.

The present invention discloses an in-situ testing system for sediment pore water chemical parameters, comprising a docking fixture, an electric push rod, a guide rail, a connecting rod, a probe, a perforated rubber cover, a large end cap, a microelectrode connector, a small end cap, a copper tube, a water collection funnel, a permeable ceramic, a microelectrode assembly, a fixing sleeve, a flange, an electronics compartment, a connecting block, a submersible pump, and a three-way valve. Based on microelectrode detection technology, the present invention employs an electric push rod to achieve stable vertical displacement of the probe, passively collects pore water through the permeable ceramic, and replaces pore water samples through a pump and valve. The system is used to continuously detect chemical parameters such as pH, H2S, and Eh in marine sediment pore water. The present invention has the advantages of a simple and reliable structure, low cost, strong environmental adaptability, low disturbance, easily replaceable parts, high precision, and high efficiency.

The invention discloses a marine sediment detecting and sampling device, and relates to the technical field of marine sediment sampling, the marine sediment detecting and sampling device comprises a sampling assembly, and further comprises a flow stabilizing assembly which is located at the bottom of the sampling assembly and used for reducing disturbance to submarine sediments when the sampling assembly rapidly descends; the distance sensor is used for monitoring the depth from the steady flow assembly to the seabed; the plugging assembly is arranged in the flow stabilizing assembly and is used for plugging the bottom of the sampling assembly and limiting the sampling assembly at the same time; and the hydraulic system is used for controlling the plugging assembly to release the limiting of the sampling assembly and controlling the plugging assembly to release the plugging of the sampling assembly when the distance sensor detects that the distance between the flow stabilizing assembly and the seabed is smaller than a preset value. Flow guide is realized under the action of the flow stabilizing hole and the flow guide plate, so that the sampling equipment quickly descends under the action of gravity, and turbulent flow caused by impact on seabed sediments is reduced.

Method for manufacturing composite cement, wherein a supplementary cementitious material is obtained from a marine sediment deposit fed by erosion of volcanic rock to form sedimented pozzolan by dredging the sediment deposit, dewatering the dredged sedimented pozzolan to a water content of below 20 wt.-% with respect to the total weight of sedimented pozzolan and water, washing the sedimented pozzolan with fresh water to a chloride content below 0.2 wt.-% with respect to the total solids, and drying to provide the supplementary cementitious material, and mixing the supplementary cementitious material with a hydraulic cement to provide the composite cement, as well as use of the obtained supplementary cementitious material for making composite cements and supplementary cementitious material and composite cement obtainable by the method or use.

This invention discloses a method for detecting metal nanoparticles in marine sediments, comprising the following steps: (1) mixing the marine sediment to be tested with water to prepare a suspension; (2) centrifuging the suspension to obtain a supernatant, which is a suspension containing metal nanoparticles; (3) performing sp-ICP-MS analysis to determine the concentration and particle size distribution of the metal nanoparticles. The detection method of this invention can extract and determine various common metal nanoparticles, including nanoparticles containing Au, Ag, Cu, Ti, or Zn. This method can detect both the concentration and particle size distribution of metal nanoparticles in sediments, is simple to operate, easy to control, requires a small sample volume, has a low detection limit, and is suitable for the extraction and determination of metal nanoparticles in marine sediments from different regions.

The application discloses a modified anode for a marine sediment microbial fuel cell and a preparation method of the modified anode and the marine sediment microbial fuel cell, and the preparation method comprises the following steps: S1, obtaining a primary anode; S2, nitrogen is introduced into a first PBS buffer solution to perform nitrogen exposure treatment, and dopamine hydrochloride is added to obtain a first electrolyte; S3, the primary anode is immersed into the first electrolyte, and electro-deposition is performed on the primary anode by a first cyclic voltammetry scanning method to obtain a PDA modified anode; S4, Fe3O4 powder is added into a second PBS buffer solution to obtain a second electrolyte; and S5, the PDA modified anode is immersed into the second electrolyte, and electro-deposition is performed on the PDA modified anode by a second cyclic voltammetry scanning method to obtain a PDA / Fe3O4 modified anode. The PDA / Fe3O4 composite is used to modify the anode, the electrochemical performance of the anode is improved, and a proper amount of amino acid is added into the sediment, so that the organic matter conversion and electron transmission efficiency of the microbial fuel cell are improved, and the electricity generation performance of the microbial fuel cell is improved.

The invention relates to the technical field of detection, and particularly discloses a method for detecting 2-aminothiazole in marine sediments in a sea area near an offshore wind field, which comprises the following steps: extracting a sample by using a mixed solution, then deriving by using hexyl chloroformate, converting a target compound 2-aminothiazole into N-(thiazole-2-yl) carbamic acid n-hexyl ester, and detecting the 2-aminothiazole in the marine sediments in the sea area near the offshore wind field by using the N-(thiazole-2-yl) carbamic acid n-hexyl ester. And enriching and purifying the obtained derivative by using a solid-phase extraction small column, and detecting by using a liquid chromatography-mass spectrometry system. The method provided by the invention can be used for efficiently, quickly and accurately analyzing and detecting, and is suitable for detecting 2-aminothiazole in marine sediments.

The present application belongs to the field of analytical chemistry, and discloses a non-equilibrium analysis method for acid volatile sulfides in marine sediments, comprising the following steps: determining the absorbance value of a marine sediment wet sample, determining the moisture content of the marine sediment wet sample, determining a standard curve, and calculating the sulfur content in the sediment dry sample. The method greatly shortens the nitrogen blowing time to 3-10 min, i.e. the pretreatment time, by controlling the high consistency of the sample and standard pretreatment process and the high consistency of each analysis step between different samples. The standard curve is obtained by adding different volumes of standard solution to the blank sample and performing the same pretreatment steps as the sample, so as to obtain the true concentration of the sample. Compared with the prior art, the present application has the characteristics of high precision and accuracy, greatly shortened analysis time, and small measurement error.

The invention discloses marine sediment detection sampling equipment and a method thereof, and relates to the technical field of sediment detection sampling. The marine sediment detecting and sampling equipment comprises a device box, a sampling pipe is arranged below the device box, the marine sediment detecting and sampling equipment further comprises a supporting column rotationally installed in the device box, a driving part for driving the supporting column to rotate in a reciprocating mode is arranged in the device box, and an installation hole is formed in the bottom of the supporting column. A connecting column is longitudinally mounted in the mounting hole in a sliding manner; wherein the sampling pipe is installed at the bottom of the connecting column, and when the supporting column rotates in a reciprocating mode, the connecting column ascends and descends in the installing hole in a reciprocating mode; the sampling pipe can effectively destroy the structure of the sediment, reduce the frictional resistance of the pipe wall and improve the sampling efficiency of the ocean sediment.

The invention relates to a wet-type rotary precise sample separation device and method for marine sediment particle size analysis. The wet-type rotary precise sample separation device comprises an anti-sedimentation sample injection unit, a rotary sample separation unit and a driving unit, the anti-sedimentation sample introduction unit comprises a sample introduction funnel and a dynamic homogenizer arranged in the sample introduction funnel, and a liquid outlet is formed in the bottom of the sample introduction funnel; the rotary sample separation unit is positioned below a liquid outlet of the anti-sedimentation sample injection unit and comprises a distribution disc capable of rotating around a vertical axis, and at least two stations for accommodating receiving containers are arranged on the distribution disc along the circumferential direction; and the driving unit is in transmission connection with the distribution disc and is used for driving the distribution disc to rotate. The device is compact in structure, easy and convenient to operate and high in sample separation precision, the influence of gravity sedimentation on sampling uniformity can be overcome in a mechanical mode, and it is ensured that each trace sample separated from original suspension liquid is highly consistent with an original sample in particle size composition, so that the requirement for high-precision laser particle size analysis is met.

The application discloses a natural gas hydrate reservoir formation age analysis method, device and system, relates to the technical field of marine natural gas hydrate exploration, and comprises the following steps: collecting marine sediment samples in a natural gas hydrate drilling core column; performing a photoelectric age test on the marine sediment samples; establishing an age-depth model of the natural gas hydrate samples according to the obtained photoelectric age and sediment depth of the marine sediment samples; calculating the sedimentation time of the natural gas hydrate reservoir according to the age-depth model of the natural gas hydrate drilling, and further determining the formation age of the natural gas hydrate. The method can accurately determine the formation age of the natural gas hydrate, avoids the interference caused by the uncertainty of the natural gas hydrate reservoir forming time, and lays a geological exploration foundation for further revealing the natural gas hydrate reservoir forming mechanism.

The invention discloses a separation device for micro-plastics in marine sediments, and belongs to the technical field of marine sediment separation. Comprising a base disc, a servo motor, a first gear disc, a circular ring guide rail frame and a separation tank, a gear circular ring is movably installed on the upper surface of the circular ring guide rail frame, the outer side of the bottom of the separation tank is integrally sleeved with the gear circular ring, and the side edge of the gear circular ring is meshed with the first gear disc. The problem of micro-plastic optical detection distortion under sediment turbidity interference is solved, a servo motor drives a gear ring to drive a magnetic attraction detection mechanism to rotate and scan along the outer wall of a separation tank, synchronous displacement of an inner wall adsorption type anti-shielding mechanism is matched, real-time purification of a detection light path area is achieved, and different from a traditional fixed sensor, the detection precision is high. A rotary scanning mode breaks through a local detection blind area, coverage type monitoring is formed under 180-degree symmetrical layout, and the multi-point continuous sampling precision of the pH value and the density gradient of the digestion solution is improved.

This invention discloses a marine sediment sampling device, belonging to the field of marine sediment sampling technology. The device includes a base, a sleeve connected to the top of the base, a sampling tube movably connected inside the sleeve, a telescopic push rod between the top of the sampling tube and the inner wall of the sleeve, a recessed hole on the base that mates with the sampling tube, a sealing assembly on the base for sealing the recessed hole, the sealing assembly movably abutting against the bottom of the sampling tube, a piston slidably connected inside the sampling tube, a one-way valve on the piston, a first elastic element between the piston and the top of the sampling tube, a positioning assembly for positioning the piston inside the sampling tube, and an anti-drop mechanism inside the sampling tube, with a dividing assembly connected to the outside of the anti-drop mechanism. This invention has a simple structure, is easy to operate, and prevents sample loss during the lifting process of the sampling tube, effectively retaining the sample in the sampling tube, resulting in a high sampling success rate and sampling rate.

The application discloses a separation device for microplastics in marine sediments and belongs to the technical field of marine sediment separation. The device comprises a base disc, a servo motor, a first gear disc, a circular guide rail frame and a separation tank. A gear ring is movably installed on the upper surface of the circular guide rail frame, the gear ring is integrally sleeved on the outer side of the bottom of the separation tank, and the side edge is engaged with the first gear disc. Through dynamic detection and self-adaptive cleaning cooperation mechanism, the problem of microplastic optical detection distortion under the interference of sediment turbidity is solved. The servo motor drives the gear ring to drive the magnetic attraction detection mechanism to rotate and scan along the outer wall of the separation tank. The synchronous displacement of the inner wall adsorption type anti-shielding mechanism realizes the real-time purification of the detection light path area. Unlike the traditional fixed sensor, the rotating scanning mode breaks through the local detection blind area and forms an overlay monitoring under the 180-degree symmetrical layout, improving the multi-point continuous sampling precision of the digestion liquid pH value and density gradient.

The application discloses a kind of marine sediment heavy metal extraction devices, including extraction tank, grinding conveying mechanism and stirring mechanism, further include the top seat of movable installation in the top of extraction tank, and fixedly installed in the screening mechanism of grinding conveying mechanism bottom, grinding conveying mechanism fixedly installed in the top side of top seat, extraction tank is rotatably installed in the top of base, one side of base is fixedly installed with side box, drive mechanism is fixedly installed in the inside of side box and extends to the inside of lifting seat.The application is energized to run through drive mechanism, while driving extraction tank, stirring mechanism, grinding conveying mechanism, screening mechanism cooperative operation, realizes the grinding, screening, rotary stirring mixing of marine sediment, ensures that acid-dissolving solution and marine sediment are fully contacted and reacted, realizes that heavy metal in marine sediment is completely dissolved and extracted, improves marine sediment heavy metal extraction speed and effect.

The embodiment of the invention provides a marine sediment sample data distribution method and related equipment, and belongs to the technical field of data analysis. The method comprises the following steps: acquiring a target marine sediment sample data set; the target marine sediment sample data set comprises a plurality of target marine sediment sample data from different data sources; according to the sequence of the multiple pieces of target ocean sediment sample data in the target ocean sediment sample data set, the multiple pieces of target ocean sediment sample data are issued to the second electronic devices respectively; obtaining an initial detection result corresponding to the target marine sediment sample data sent by each second electronic device; and performing mass comparison on the initial detection result corresponding to the target marine sediment sample data to obtain a target detection result. By implementing the embodiment of the invention, the accuracy of the obtained target detection result can be ensured, so that the detection efficiency and accuracy of treating a large number of marine sediment samples are improved.

The utility model discloses a marine sediment in-situ multi-parameter measuring device which comprises an insulating shell and a main control module installed in the shell, a conductivity measuring unit is embedded in the outer side of the shell, a heat conductivity measuring unit is further arranged in the shell, and the conductivity measuring unit and the heat conductivity measuring unit are respectively and electrically connected with the main control module. The device has the beneficial effects that the conductivity measuring unit is embedded in the outer side of the insulating shell, the heat conductivity measuring unit is arranged in the shell, the conductivity measuring unit and the heat conductivity measuring unit are used for respectively detecting the conductivity and the heat conductivity of the ocean sediment, and the acquired data are sent to the main control module for real-time processing; and the synchronous monitoring capability of the device is enhanced.

The application discloses a marine sediment classification space distribution visualization method, equipment, medium and product, and the method comprises the following steps: collecting sediment samples of each space sampling point in a target sea area, and obtaining sediment grain composition data; calculating the sediment energy intensity of each point, combining a standard sediment classification threshold set, and determining the corresponding optimized sediment classification threshold set of each point; using the optimized threshold set and the grain composition data to determine the sediment bottom type of each sampling point; constructing a space triangulation network based on all the sampling points, combining the grain data, the bottom type and the standard threshold set, and interpolating the classification boundary points on the triangulation network; dividing the sea area into polygonal regions corresponding to the bottom types according to the boundary points, performing automatic color filling and type labeling, and finally generating a marine sediment space distribution map. The technical scheme of the embodiment of the application can realize comprehensive and accurate classification of marine sediments and complete the visualization mapping of the space distribution of the marine sediments.

The marine sediment thermoelectric acoustic detection device can simultaneously measure sediment heat, electricity, sound multi-parameters, realize miniaturized structure design, can effectively reduce the additional resistance caused by the mounted underwater acoustic transducer when pouring into the sediment, realize the design purpose of simultaneously having heat, electricity, sound multi-parameter measurement capability and accurate and reliable measurement data. The electronic cabin including a built-in communication module is welded with an adapter at the bottom of the electronic cabin; the adapter is communicated with a transverse pipe on one side, and the transverse pipe is connected with a transmitting transducer at the end; a plurality of first connecting pieces are arranged, and a group of underwater acoustic transducers are connected between adjacent two groups of first connecting pieces; a plurality of copper rings for measuring electrical conductivity are connected in series at the bottom of the last group of first connecting pieces, and a group of third connecting pieces are connected between adjacent two groups of copper rings for measuring electrical conductivity and at the bottom of the last group of copper rings for measuring electrical conductivity; the third connecting piece of the last group is connected with a fourth connecting piece, and a plurality of groups of NTC thermistors are equidistantly arranged in the probe rod structure.

The invention discloses a modified anode for a marine sediment microbial fuel cell, a preparation method of the modified anode and the marine sediment microbial fuel cell. The preparation method comprises the following steps: S1, obtaining a primary anode; s2, nitrogen is introduced into the first PBS buffer solution for nitrogen aeration treatment, dopamine hydrochloride is added, and a first electrolyte is obtained; s3, the primary anode is immersed in a first electrolyte, electro-deposition is conducted on the primary anode through a first cyclic voltammetry scanning method, and a PDA modified anode is obtained; s4, Fe3O4 powder is added into the second PBS buffer solution, and a second electrolyte is obtained; and S5, the PDA modified anode is immersed in a second electrolyte, electro-deposition is conducted on the PDA modified anode through a second cyclic voltammetry scanning method, and the PDA / Fe3O4 modified anode is obtained. The anode is modified through PDA / Fe3O4 compounding, and the electrochemical performance of the anode is improved; a proper amount of amino acid is added into the sediment, so that the organic matter conversion and electron transfer efficiency of the microbial fuel cell is enhanced, and the electricity generation performance of the microbial fuel cell is improved.

This invention relates to the field of detection, specifically to an in-situ method for determining the sulfate reduction rate of marine sediments. The in-situ determination method provided by this invention involves injecting a certain amount of... 34 S stable isotope labeled SO4 2‑ (in 34 S abundance was much higher than that of SO4 under natural conditions. 2‑ middle 34 The abundance of S was 4.2%, when SO4 2‑ When reduced, SO4 is marked 2‑ Unlabeled SO4 2‑ Converted proportionally to S 2‑ The S generated at this time 2‑ middle 34 The abundance of S will increase. Determination of labeled SO4 2‑ Before (control CK) and marked SO4 2‑ - S in the sediment after a period of time (ΔT) 2‑ of 34 By measuring the sulfate abundance difference and other relevant parameters, the sulfate reduction rate can be calculated. This invention enables in-situ measurement of sulfate reduction rates in marine sediments, yielding results that conform to objective laws and are highly accurate. The measurement process is simple, safe, and stable.

The invention discloses a marine sediment heavy metal determination method based on rapid digestion. The marine sediment heavy metal determination method comprises the following steps: S1, digestion; the method comprises the following steps: weighing a standard sample, putting the standard sample into a polypropylene volumetric tube, wetting the sample, adding mixed acid, and digesting in a graphite digestion instrument; the exterior of the polypropylene volumetric tube is sealed; s2, detecting; cooling and quantifying after digestion is completed, taking supernate, diluting and detecting; preparing a calibration solution by adopting the digestion blank solution so as to eliminate a matrix effect caused by acid for digestion; 103Rh, 115In and 209Bi are selected as internal standard elements, and the on-line internal standard concentration is 50 [mu] g / L. According to the method, the polypropylene volumetric tube and the graphite digestion instrument are adopted for digestion, the digestion time is obviously shortened, the digestion temperature is reduced, the pretreatment efficiency is improved, and meanwhile, by optimizing the calibration solution preparation method and the conditions such as internal standard elements and internal standard concentration, it is ensured that the accuracy and precision of the method meet the test requirements.

The invention relates to the technical field of mercury isotope analysis, in particular to a catalytic pyrolysis method for mercury isotope analysis of a marine sediment sample. According to the method, pyrolysis is carried out under the action of the composite catalyst, efficient in-situ removal of complex matrixes can be realized in cooperation with pyrolysis conditions, and then the recovery rate of mercury and the accuracy of isotope detection results are improved. The method provided by the invention solves the problems of low mercury recovery rate, instability, serious matrix interference and the like of a marine sediment sample with a complex matrix. According to the method, the mercury recovery rate, the matrix removal efficiency and the accuracy and precision of mercury concentration and isotope analysis of the method are comprehensively verified by utilizing various marine sediment standard substances and actual environmental samples, and the result shows that the method has excellent reliability and accuracy in the aspect of mercury concentration and isotope analysis. The catalytic pyrolysis method provided by the invention can provide key technical support for accurately analyzing mercury records in marine sediments.

The invention discloses a device and a method for testing the strength of ocean sediments in different consolidation states. The device comprises a test board, a test barrel, a door-shaped stress application rod and a sample container, wherein a precise pressurizing device is mounted at the bottom of the test board; the test barrel and the door-shaped stress application rod are arranged on the test board; a mechanical sensor and a pressurizing rod displacement sensor are arranged in the precise pressurizing device; the sample container is provided with a cover plate, two sides of the sample container are provided with cross-shaped holes, and the testing barrel is provided with two mechanical property testing devices matched with the testing barrel. According to the testing method, the downward displacement of the pressing block and the volume of discharged water are measured at the same time, consolidation compression parameters of the sediment are calculated, the accuracy of a consolidation compression experiment is effectively improved, and the penetration resistance test and the shear strength test are measured through the mechanical property testing device. According to the invention, a sediment consolidation compression experiment, a penetration resistance test and a shear strength test can be completed by using one ocean sediment sample, and particularly, the device has obvious advantages for obtaining deep-sea sediment samples with relatively high cost and relatively small sample amount.

Method for manufacturing composite cement, wherein a supplementary cementitious material is obtained from a marine sediment deposit fed by erosion of volcanic rock to form sedimented pozzolan by dredging the sediment deposit, dewatering the dredged sedimented pozzolan to a water content of below 20 wt.-% with respect to the total weight of sedimented pozzolan and water, washing the sedimented pozzolan with fresh water to a chloride content below 0.2 wt.-% with respect to the total solids, and drying to provide the supplementary cementitious material, and mixing the supplementary cementitious material with a hydraulic cement to provide the composite cement, as well as use of the obtained supplementary cementitious material for making composite cements and supplementary cementitious material and composite cement obtainable by the method or use.

This invention provides a method and kit for extracting microbial DNA from marine sediments. The extraction method includes: a) washing the marine sediments with a washing buffer to obtain a washed sample; wherein the washing buffer includes spermidine and sodium pyrophosphate; b) lysing the microbial cells in the washed sample to obtain a lysed sample; c) recovering, screening, and purifying the DNA from the lysed sample to obtain microbial DNA. This method solves the problem of poor DNA extraction efficiency in existing technologies and is applicable to the field of DNA extraction.