A method for determining the effect of weathering of magnesium-containing silicate rocks on the microalgae biological carbon sink

Abstract

The present invention discloses a method for determining the effect of weathering of magnesium-containing silicate rocks on the microalgae biological carbon sink, including: culturing two groups of microalgae under the same culture conditions, one group adding magnesium-containing silicate rocks and microalgae as the experimental group, and one group adding only microalgae without adding silicate rocks as the blank group; for the experimental group, culturing the microalgae to be tested in the culture solution for i days, and measuring the magnesium ion concentration Ci and chlorophyll a concentration Chi in the culture solution every day; taking the algal bodies of the experimental group at 0 day and T days of culture, separating the magnesium-containing silicate rocks by multiple low-speed centrifugations, measuring the chlorophyll a content Cchl-a of the algal bodies, then transferring the algal bodies into a digestion tank, digesting for a set time at a preset temperature using an HNO3 and H2O2 digestion system, and measuring the magnesium ion concentration C of the digestion solution Mg , and calculating Cpi, Ti, and C respectively Bi(R‑M) ; the present invention can ensure the full separation of microalgae and rocks, and can accurately obtain the contribution effect of weathering of magnesium-containing silicate rocks on the microalgae biological carbon sink.

Description

Technical Field

[0001] The present invention relates to a method for measuring the bio - carbon sequestration effect of magnesium - containing silicate rock weathering on microalgae, and belongs to the fields of ecological environment monitoring, treatment and restoration. Background Art

[0002] The concentration of global atmospheric carbon dioxide (CO2) is gradually increasing, global climate is warming, and the global carbon cycle has become a hot topic of international scientific concern. The global carbon storage repositories mainly include fossil fuels, land, atmosphere, ocean, carbonate rocks, etc. With the exploitation and combustion of fossil fuel resources by humans and the reclamation of land, the global carbon cycle in the pre - agricultural period has been disturbed, and the carbon storage in the atmosphere has increased by 223 billion tons from the pre - agricultural period to the modern era. The carbon cycle of the Earth system affects global climate change, which has had a major impact on the world economy, society and ecological environment, etc. The increase in atmospheric CO2 concentration brings severe challenges to the sustainable development of the economies of various countries and national security, etc.

[0003] CO2 is the link of the global carbon cycle, and photosynthesis is the main driving force for driving the carbon cycle. Phytoplankton are the main producers in the water environment, and the photosynthesis of phytoplankton is the key process of the carbon cycle in water bodies. Although the biomass in the ocean only accounts for 1% of the earth, their photosynthesis accounts for about 50% of the global total. Microalgae are single - celled or multi - celled photosynthetic phytoplankton living in aquatic environments. Through photosynthesis, they can convert CO2, water and light energy into oils, carbohydrates and proteins. As the most important primary productivity in water bodies such as lakes and oceans, microalgae are diverse in species. They can use sunlight, water and CO2 to rapidly carry out photoautotrophic growth and are the main source of lake carbon sinks. The weathering of magnesium - containing silicate rocks results in a sink of CO2, which plays a decisive role in climate regulation. In the weathering process, microalgae, as an ancient life form, run through the entire geology. Microalgae can utilize the bicarbonate ions (HCO3 - ) produced by weathering to form a "biological pump", and microalgae play an important role in the weathering process.

[0004] Based on the above, the method for calculating the bio - carbon sequestration effect of magnesium - containing silicate rock weathering on microalgae is of crucial significance in global carbon sink calculation. In the calculation of rock weathering carbon sink, the positive and negative effects of the magnesium - containing silicate rock weathering process on bio - carbon sequestration represent the impact of rock weathering on microalgae carbon sink. However, there is currently no method for calculating the bio - carbon sequestration effect of magnesium - containing silicate rock weathering on microalgae. Therefore, the present invention constructs a quantitative method for the bio - carbon sequestration effect of magnesium - containing silicate rock weathering on microalgae through laboratory control experiments and equations to fill the gap in the current method. Summary of the Invention

[0005] Based on the above, the present invention provides a method for measuring the effect of magnesium silicate rock weathering on microalgae biological carbon sink, which can overcome the problem that it is difficult to quantitatively measure the effect of magnesium silicate rock weathering on microalgae biological carbon sink in the prior art.

[0006] The technical solution of the present invention is: a method for measuring the effect of magnesium silicate rock weathering on microalgae biological carbon sink, comprising the following steps:

[0007] Cultivate two groups of microalgae under the same culture conditions. One group is added with magnesium silicate rock and microalgae as the experimental group, and the other group is added with only microalgae without adding silicate rock as the blank group. Cultivating the two groups of microalgae under the same culture conditions means that there are no other differences between the two groups of algal bodies except whether silicate rock is added. Control the same culture conditions and microalgae culture materials to ensure the reliability of experimental data;

[0008] For the blank group, cultivate the microalgae to be measured in the culture medium for i days, measure the chlorophyll a concentration Chi in the culture medium every day, and calculate the photosynthetic carbon concentration C Bi(M) where C Bi(M) = 0.74(Chi - Ch0), where Ch0 is the chlorophyll a concentration at day 0 of the blank group culture, and Chi is the chlorophyll a concentration at day i of the blank group culture;

[0009] For the experimental group, cultivate the microalgae to be measured in the culture medium for i days, measure the magnesium ion concentration Ci and the chlorophyll a concentration Cchl-a in the culture medium every day; calculate the photosynthetic carbon concentration C Bi(R-M) ; Take the algal bodies of the experimental group at day 0 and day T of culture. After separating the magnesium silicate rock by multiple low-speed centrifugations, measure the chlorophyll a concentration Cchl-a of the algal bodies, then transfer the algal bodies into a digestion tank, and use the HNO3 and H2O2 digestion system to digest for a set time at a preset temperature, and measure the magnesium ion concentration C Mg in the digestion solution, and calculate Cpi, Ti and C Bi(R-M) respectively, where Cpi is the magnesium ion content in the chlorophyll a of the algal bodies at the i-day time point, Ti is the dissolved magnesium ion concentration of the magnesium silicate rock at the i-time point, and C Bi(R-M) is the photosynthetic carbon concentration in the treatment group at the i-time point;

[0010] According to the formula WC i =(C Bi(R-M) -C Bi(M) ), calculate the dissolved carbon concentration WC i brought by the weathering of magnesium silicate rock at the i-time point in the experimental group; By adding microalgae culture groups with and without magnesium silicate rock, analyze the photosynthetic carbon concentrations under the two experimental treatment conditions, clarify the difference in photosynthetic carbon concentrations between the control group and the experimental group, and obtain the dissolved carbon concentration WC i, which ensures the accuracy of this method;

[0011] Perform equation fitting on the dissolved carbon concentration WC i and the magnesium ion content Ti leached from magnesium silicate rock to obtain the functional relationship WC(Ti) between WC i and Ti; after taking the derivative of the equation WC(Ti) with respect to Ti, the effect E of the weathering of magnesium silicate rock on the microalgae biological carbon sink can be obtained Bi , that is

[0012] E Bi = d(C(Ti)) / d(Ti);

[0013] This step accurately calculates the effect of the weathering of magnesium silicate rock on the microalgae biological carbon sink from a mathematical principle.

[0014] Preferably, the method of using multiple low-speed centrifugations to separate magnesium silicate rock and microalgae samples is as follows: Take the mixed sample of the experimental group and place it in a centrifuge tube. After shaking well, set the rotation speed below 500 r / min, centrifuge to collect the supernatant, and discard the precipitate; repeat the low-speed centrifugation of the supernatant twice; take an appropriate amount of the supernatant, centrifuge at 4000 r / min to collect the algae, add ethanol to extract chlorophyll and measure the chlorophyll a concentration to obtain Cchl-a; wash the ethanol extraction solution and the precipitate with ethanol, volatilize the ethanol on a hot plate below 80 °C until the last drop, cool and then add the HNO3 and H2O2 digestion system for digestion, and measure the magnesium ion concentration C of the digestion solution Mg , which ensures the full separation of microalgae and rock and reliable measurement of data results.

[0015] Preferably, the calculation formula for Cpi is:

[0016] Cpi = Cp0 + i×(Cp T -Cp0) / T

[0017] In the formula, Cp0 is the magnesium ion content per unit chlorophyll a of the algae on day 0, and Cp T is the magnesium ion content per unit chlorophyll a of the algae on day T, which is calculated according to the following formula:

[0018] Cp T = C Mg / Cchl-a.

[0019] Preferably, the calculation formula for Ti is:

[0020] Ti = (C i -C0) + (RChi×Cp i -RCh0×Cp0)

[0021] In the formula, Cp irepresents the magnesium ion content in the algal chlorophyll a at time point i; Cp0 represents the magnesium ion content in the algal chlorophyll a at the initial time point, C i is the magnesium ion concentration in the culture medium at time point i, and C0 is the magnesium ion concentration in the culture medium at the initial time point; RChi is the chlorophyll a concentration in the culture medium at time point i, and RCh0 is the chlorophyll a concentration in the culture medium at the initial time point.

[0022] Preferably, C Bi(R-M) The calculation formula of is:

[0023] C Bi(R-M) = 0.74(RChi - RCh0)

[0024] In the formula, RChi is the chlorophyll a concentration in the culture medium of the experimental group at time point i, and RCh0 is the chlorophyll a concentration in the culture medium of the experimental group at the initial time point.

[0025] The technical principle of the present invention is:

[0026] The weathering of magnesium-containing silicate rock can be expressed as:

[0027] 4CO2 + Mg2[SiO4] + 4H2O → 2Mg 2+ + 4HCO3 - + H4SiO4(1)

[0028] Therefore, the magnesium dissolution amount (Ti) represents the weathering amount of magnesium-containing silicate rock. Set the treatment of adding microalgae without adding magnesium-containing silicate rock powder as the blank group, and set the treatment group of adding both magnesium-containing silicate rock powder and microalgae as the experimental group. In the experimental group, a part of the dissolved magnesium ions is absorbed by the algal bodies, and a part remains in the culture medium. After magnesium is dissolved, a part is absorbed by the algal bodies, and a part remains in the culture medium. The microalgae in the experimental group are cultured in the culture medium for i days, and the magnesium ion concentration and the chlorophyll a concentration of the microalgae in the culture medium are measured every day; the following parameters can be obtained, C i : the magnesium ion concentration in the culture medium at time point i; C0: the magnesium ion concentration in the culture medium at the initial time point; RChi: the chlorophyll a concentration in the culture medium at time point i; RCh0: the chlorophyll a concentration in the culture medium at the initial time point; then the calculation formula of the magnesium amount Ti dissolved from silicate rock at different culture times is:

[0029] Ti = (C i - C0) + (RChi × Cp i - RCh0 × Cp0) (2)

[0030] In the formula, Cp i represents the magnesium ion content in the algal chlorophyll a at time point i; Cp0 represents the magnesium ion content in the algal chlorophyll a at the initial time point.

[0031] Cp in the above equation (2) i It is difficult to obtain Cp and Cp0. The reason is that after the experimental group is cultured for several days, most of the microalgae and rock powder are separated by gravity, but a small part forms flocs that are difficult to separate. Therefore, this data cannot be directly measured and obtained. The present invention adopts the following experimental steps to obtain the separation: Take the experimental treatment groups containing magnesium silicate rock and microalgae cultured for 0 days and T days, and use multiple low-speed centrifugations to separate the magnesium silicate rock. Specifically, take the experimental treatment mixed sample and place it in a centrifuge tube. After shaking well, set the rotation speed below 500 r / min, centrifuge to collect the supernatant, and discard the precipitate; after repeating the low-speed centrifugation of the supernatant twice. Take an appropriate amount of the supernatant, centrifuge at 4000 r / min to collect the microalgae, add ethanol to extract chlorophyll and measure the chlorophyll a content to obtain Cchl-a. Wash the ethanol extraction solution and precipitate with ethanol, volatilize the ethanol on a hot plate below 80 °C until the last drop, cool, add 3 mL of HNO3 and 1 mL of H2O2 digestion system, digest at 180 °C for 8 hours, and measure the magnesium ion concentration C of the digestion solution Mg ; ensuring the full separation of microalgae and rocks. According to the measured chlorophyll concentrations Cchl-a of the experimental treatment groups of magnesium silicate rock and microalgae cultured for 0 days and T days, and the magnesium ion content C Mg ; According to the formula Cp T =C Mg / Cchl-a, calculate Cp0 (the magnesium ion content in the unit chlorophyll a of the 0-day microalgae) and Cp T (the magnesium ion content in the unit chlorophyll a of the T-day microalgae). Due to the difficulty of this separation, during the microalgae culture process, it is impossible to sample the microalgae at any time to measure the magnesium ion content (Cp i ) in the unit chlorophyll a. Therefore, for convenience, the linear interpolation method Cpi = Cp0 + i×(Cp T - Cp0) / T is used to calculate the magnesium ion content Cpi in the chlorophyll a at the i-day time point. Substitute the above measured values into formula (2) to calculate the magnesium ion content Ti leached from the magnesium silicate rock at the i-time point. The calculation formula of Ti is: Ti = (C i - C0) + (RChi×Cp i - RCh0×Cp0).

[0032] The chlorophyll a content in algae is widely used to characterize the biomass of water phytoplankton algae. Therefore, the biomass in the experimental treatment group and the control group can be replaced by the chlorophyll a content. The mass fraction of carbon in chlorophyll a (C 55 H 72 MgN4O5) is 0.74. Therefore, the photosynthetic carbon concentration (C Bi(R-M) ) of microalgae and C Bi(M)

[0033] Can be respectively expressed as:

[0034] C Bi(R-M) = 0.74(RChi - RCh0) (3)

[0035] C Bi(M) = 0.74(Chi - Ch0) (4)

[0036] Wherein, RChi is the chlorophyll a concentration in the culture solution at the time point i of the experimental group, and RCh0 is the chlorophyll a concentration in the culture solution at the initial time point of the experimental group. Ch0 is the chlorophyll a concentration in the culture solution when the blank group is cultured for 0 days, and Chi is the chlorophyll a concentration in the culture solution when the blank group is cultured for i days.

[0037] Substitute the measured values of RChi, RCh0, RChi, and RCh0 into formulas (3) and (4) respectively to obtain C Bi(R-M) (photosynthetic carbon concentration in the treatment group at the i time point) and C Bi(R-M) (photosynthetic carbon concentration in the blank group at the i time point), calculate the photosynthetic carbon concentration C Bi(R-M) of the experimental treatment group with silicate rock and microalgae added at the i time point, and the photosynthetic carbon concentration C Bi(M) of the experimental blank group with microalgae added at the i time point. Take the difference between the two to obtain the dissolution carbon concentration WC i ,

[0038] WC i = (C Bi(R-M) - C Bi(M) ) (4)

[0039] According to the experimental setup, the difference in photosynthetic carbon between the blank group and the experimental group is caused by whether rock powder is added, that is, the dissolution carbon concentration WC i ,, therefore, perform an equation simulation on the dissolution carbon concentration WC i , and the magnesium ion content Ti leached from the magnesium-containing silicate rock to obtain the functional relationship WC(Ti) between WC i and Ti. After taking the derivative of the equation WC(Ti) with respect to Ti, the contribution effect E Bi of the weathering of magnesium-containing silicate rock to the microalgae biological carbon sink can be obtained, that is

[0040] E Bi = d(WC(Ti)) / d(Ti) (5)

[0041] The beneficial effects of the present invention are as follows:

[0042] 1) The present invention can obtain the contribution effect of the weathering of magnesium-containing silicate rock to the microalgae biological carbon sink.

[0043] 2) The measurement of the present invention is simple and the operation is convenient and fast.

[0044] 3) By ensuring the full separation of microalgae and rocks, the present invention realizes the accurate measurement of the chlorophyll a content per unit algal body of microalgae under the action of rock weathering in the experiment, and accurately obtains the contribution effect of magnesium-containing silicate rock weathering on the microalgae biological carbon sink. Specific Embodiments

[0045] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementations disclosed below.

[0046] Example 1: The biological carbon sink effect of olivine weathering on Chlamydomonas reinhardtii under different carbon utilization conditions

[0047] The culture materials are: Chlamydomonas reinhardtii. Culture medium: Magnesium-depleted SE medium (sodium sulfate is used instead of magnesium sulfate in an equal amount), and its pH value is 6.3. The basic culture conditions are: light cycle L / D: 12h / 12h; temperature 25°C; light intensity is 100 μmol·m -2 ·s -1 .

[0048] Chlamydomonas reinhardtii is cultured under the same magnesium-depleted SE medium conditions. One group is added with olivine and microalgae, and the other group is only added with Chlamydomonas reinhardtii without adding olivine; three experimental parallels are set for each group of treatments.

[0049] Chlamydomonas reinhardtii is cultured under the same magnesium-depleted SE medium and added with extracellular carbonic anhydrase inhibitor (AZ). One group is added with olivine and Chlamydomonas reinhardtii, and the other group is only added with Chlamydomonas reinhardtii without adding olivine; three experimental parallels are set for each group of treatments.

[0050] Chlamydomonas reinhardtii is cultured in the above culture solution for 7 days. The magnesium ion concentration in each group of culture solutions and the chlorophyll a concentration of microalgae in the culture solution are measured every day; the following parameters C can be obtained i: The concentration of magnesium ions in the culture medium at time point i; C0: The concentration of magnesium ions in the culture medium at the initial time point; RChi(Chi): The concentration of chlorophyll a in the culture medium at time point i; RCh0(Ch0): The concentration of chlorophyll a in the culture medium at the initial time point; At the same time, take the algal bodies of the experimental treatment group with olivine and Chlamydomonas reinhardtii cultured for 0 days and 7 days. After separating the olivine by multiple low-speed centrifugations, measure the chlorophyll a content of the algal bodies, then transfer the algal bodies into a digestion tank, and use a digestion system of 3 mL HNO3 and 1 mL H2O2 to digest at 180 °C for 8 hours, and measure the concentration of magnesium ions in the digestion solution. According to the measured chlorophyll a concentrations Cchl-a of the algal bodies of the experimental treatment group with olivine and Chlamydomonas reinhardtii cultured for 0 days and 7 days, and the magnesium ion content C Mg ; The following parameter Cp can be obtained i : The content of magnesium ions in chlorophyll a of the algal body at time point i; Cp0: The content of magnesium ions in chlorophyll a of the algal body at the initial time point. The measurement results are shown in Table 1 - Table 3.

[0051] Table 1 Concentration of magnesium ions in the culture medium at time point i

[0052] Chlamydomonas reinhardtii <![CDATA[C0]]> <![CDATA[C1]]> <![CDATA[C3]]> <![CDATA[C5]]> <![CDATA[C7 <!-- 4 -->]]> C.R 0 0 0 0 0 C.R+R 0 0.221 0.123 0.00 0.01 C.R+AZ 0 0 0 0 0 C.R+R+AZ 0 0.212 0.247 0.293 0.474

[0053] Note: C.R: Represents the treatment group with Chlamydomonas reinhardtii added;

[0054] C.R+R: Represents the treatment group with Chlamydomonas reinhardtii and olivine samples added;

[0055] C.R+AZ: Represents the treatment group with Chlamydomonas reinhardtii and AZ added;

[0056] C.R+R+AZ: Represents the treatment group with Chlamydomonas reinhardtii, AZ, and olivine samples added.

[0057] Table 2 Concentration of chlorophyll in the culture medium at time point i

[0058]

[0059]

[0060] Table 3 Cchl-a and C of algal bodies at 0d and 7d Mg value

[0061]

[0062] According to the relevant experimental treatment data in Table 1 - Table 3, according to the calculation method of the present invention:

[0063] The first step: Calculate Cp0 and Cp7. According to the formula Cp T = C Mg / Cchl-a calculates Cp0 (the content of magnesium ions per unit chlorophyll a in the culture solution on day 0) and Cp7 (the content of magnesium ions per unit chlorophyll a in the culture solution on day 7).

[0064] Step 2: Calculate Cpi. According to the linear interpolation method, Cpi = Cp0 + i×(Cp7 - Cp0) / 7, and calculate the content of magnesium ions Cpi in the chlorophyll a of the algal body at the i-th time point.

[0065] Step 3: Calculate Ti. Substitute the measured values into the formula Ti = (C i - C0) + (RChi×Cp i - RCh0×Cp0); calculate the content of magnesium ions Ti released from the magnesium-containing silicate karst at the i-th time point.

[0066] Step 4: Calculate C Bi(R-M) and C Bi(M) . Substitute the measured values of RChi, RCh0, Chi, and Ch0 into the formulas C Bi(R-M) = 0.74(RChi - RCh0) and C Bi(M) = 0.74(Chi - Ch0); obtain the photosynthetic carbon concentration at the i-th time point for each group.

[0067] Step 5: Calculate the dissolved carbon concentration WC i brought by the weathering of magnesium-containing silicate rock at the i-th time point. The calculation method is: WC i = (C Bi(R-M) - C Bi(M) ).

[0068] Step 6: Fit the dissolved carbon concentration WC i with the content of magnesium ions Ti released from the magnesium-containing silicate karst to obtain the functional relationship WC(Ti) between WC i and Ti.

[0069] Step 7: Calculate E Bi . After taking the derivative of WC(Ti) with respect to Ti, calculate the biological carbon sequestration effect E Bi of peridotite on Chlamydomonas reinhardtii, and E Bi = d(WC(Ti)) / d(Ti).

[0070] The above calculation results are shown in Tables 4 - 10.

[0071] Table 4 Cp0, Cp7, Cpi

[0072]

[0073]

[0074] Table 5 Ti

[0075] Chlamydomonas reinhardtii T1 T3 T5 T7 Ti C.R+R 0.26 0.67 1.11 1.44 0.074+0.199i C.R+R+AZ 0.13 0.39 0.76 1.03 -0.0365+0.1535i

[0076] Table 6 C Bi(R-M)

[0077] Chlamydomonas reinhardtii <![CDATA[C B1(R-M) > <![CDATA[C B3(R-M) > <![CDATA[C B5(R-M) > <![CDATA[C B7(R-M) > C.R+R -0.41 -0.16 -0.04 -0.10 C.R+R+AZ -0.54 -0.18 0.13 0.01

[0078] Table 7 C Bi(M)

[0079] Chlamydomonas reinhardtii <![CDATA[C B1(M) > <![CDATA[C B3(M) > <![CDATA[C B5(M) > <![CDATA[C B7(M) > C.R -0.30 -0.17 -0.17 -0.21 C.R+AZ -0.34 -0.30 -0.07 0.04

[0080] Table 8 WC i

[0081]

[0082] Table 9 WC(Ti), E Bi

[0083] Chlamydomonas reinhardtii WC(Ti) C.R+R <![CDATA[-0.00875((Ti - 0.074) / 0.199) 2 +0.109((Ti - 0.074) / 0.199) - 0.21725]]> C.R+R+AZ <![CDATA[-0.03438((Ti + 0.0365) / 0.1535) 2 + 0.03045((Ti + 0.0365) / 0.1535)-0.47363]]>

[0084] Table 10 E Bi

[0085] Chlamydomonas reinhardtii <![CDATA[E Bi = d(WC(Ti)) / d(Ti)]]> C.R+R -0.088i+0.5477 C.R+R+AZ -0.448i+0.1984

[0086] It can be seen from Table 10 that under the two culture conditions of adding AZ and not adding AZ, the effect of peridotite weathering on the microalgae biological carbon sink changes from positive to negative over time. This indicates that peridotite weathering promotes the increase of the microalgae biological carbon sink in the early stage. However, as the culture time continues and in the case of insufficient other nutrients that are not contained in some rocks, more weathering generates more stress, which has a negative effect on the microalgae carbon sink. This is consistent with the actual situation. The method for measuring the effect of magnesium-containing rock weathering on the microalgae biological carbon sink can be used, on the one hand, to evaluate the effect of the rock weathering process on the biological carbon sink; on the other hand, it can also be used to calculate the total carbon sink of the biological carbon sink and the rock weathering carbon sink in the carbon sequestration project.

[0087] Example 2: Effect of peridotite weathering on the biological carbon sink of Chlorella pyrenoidosa under different carbon utilization conditions

[0088] The culture material is: Chlorella pyrenoidosa. The magnesium-free SE medium (using an equal amount of sodium sulfate instead of magnesium sulfate) with a pH value of 6.3. The basic culture conditions are: light cycle L / D: 12h / 12h; temperature 25°C; light intensity 100 μmol·m -2 ·s -1 .

[0089] Chlorella pyrenoidosa was cultured under the same magnesium-free SE medium conditions. One group was supplemented with peridotite and Chlorella pyrenoidosa, and the other group was supplemented only with Chlorella pyrenoidosa without peridotite. Three experimental replicates were set for each treatment.

[0090] Chlorella pyrenoidosa was cultured under the same magnesium-free SE medium supplemented with extracellular carbonic anhydrase inhibitor (AZ). One group was supplemented with peridotite and Chlorella pyrenoidosa, and the other group was supplemented only with Chlorella pyrenoidosa without peridotite. Three experimental replicates were set for each treatment.

[0091] Chlorella pyrenoidosa was cultured in the above culture solution for 7 days. The magnesium ion concentration in the culture solution of each group and the chlorophyll a concentration of microalgae in the culture solution were measured every day. The following parameters C i : Magnesium ion concentration in the culture solution at time point i; C0: Magnesium ion concentration in the culture solution at the initial time point; RChi(Chi): Chlorophyll concentration in the culture solution at time point i; RCh0(Ch0): Chlorophyll a concentration in the culture solution at the initial time point; At the same time, the algal bodies of the experimental treatment group supplemented with peridotite and Chlorella pyrenoidosa were taken at 0 day and 7 days of culture. After separating peridotite by multiple low-speed centrifugations, the chlorophyll a content of the algal bodies was measured. Then the algal bodies were transferred into a digestion tank and digested with a 3 mL HNO3 and 1 mL H2O2 digestion system at 180 °C for 8 hours, and the magnesium ion concentration of the digestion solution was measured. According to the measured chlorophyll concentration Cchl-a of the algal bodies of the experimental treatment group supplemented with peridotite and Chlorella pyrenoidosa at 0 day and 7 days of culture, and the magnesium ion content C Mg ; The following parameters Cp i : Magnesium ion content in chlorophyll a of algal bodies at time point i; Cp0: Magnesium ion content in chlorophyll a of algal bodies at the initial time point. The measurement results are shown in Tables 4 - 6.

[0092] Table 4 Magnesium ion concentration in the culture solution at time point i

[0093] Chlorella pyrenoidosa <![CDATA[C0]]> <![CDATA[C1]]> <![CDATA[C3]]> <![CDATA[C5]]> <![CDATA[C7]]> C.P+R 0 0.16 0.10 0.03 0.00 C.P+R+AZ 0 0.20 0.27 0.30 0.45

[0094] Note: C.P: Represents the treatment group supplemented with Chlorella pyrenoidosa.

[0095] C.P+R: Represents the treatment group supplemented with Chlorella pyrenoidosa and peridotite samples.

[0096] C.P+AZ: Represents the treatment group supplemented with Chlorella pyrenoidosa and AZ.

[0097] C.P+R+AZ: Represents the treatment group supplemented with Chlorella pyrenoidosa, AZ, and peridotite samples.

[0098] Table 5 Chlorophyll concentration in the culture solution at time point i

[0099]

[0100]

[0101] Table 6 Cchl-a and C of 0d and 7d thalli Mg value

[0102]

[0103] According to the relevant experimental treatment data in Tables 4 - 6, according to the calculation method of the present invention:

[0104] First step: Calculate Cp0 and Cp7. According to the formula Cp T = C Mg / Cchl-a, calculate Cp0 (the content of magnesium ions in unit chlorophyll a in the culture solution on day 0) and Cp7 (the content of magnesium ions in unit chlorophyll a in the culture solution on day 7).

[0105] Second step: Calculate Cpi. According to the linear interpolation method Cpi = Cp0 + i×(Cp7 - Cp0) / 7, calculate the content of magnesium ions Cpi in the chlorophyll a of the thalli at the i-day time point;

[0106] Third step: Calculate Ti. Substitute the measured values into the formula Ti = (C i - C0)+(RChi×Cp i - RCh0×Cp0); calculate the content of magnesium ions Ti released from the magnesium-containing silicate karst dissolution at the i-time point;

[0107] Fourth step: Calculate C Bi(R-M) 、C Bi(M) , substitute the measured RChi, RCh0, Chi, and Ch0 values into the formulas C Bi(R-M) = 0.74(RChi - RCh0) and C Bi(M) = 0.74(Chi - Ch0); obtain the photosynthetic carbon concentration at the i-time point of each group;

[0108] Fifth step: Calculate the dissolution carbon concentration WC i brought by the weathering of magnesium-containing silicate rock at the i-time point. The calculation method is: WC i = (C Bi(R-M) - C Bi(M) );

[0109] Sixth step: Fit the dissolution carbon concentration WC i with the content of magnesium ions Ti released from the magnesium-containing silicate karst dissolution to obtain the functional relationship WC(Ti) between WC i and Ti;

[0110] Seventh step: Calculate E Bi, the bio - carbon sequestration effect E of peridotite on Chlamydomonas reinhardtii is calculated by taking the derivative of WC(Ti) with respect to Ti Bi , E Bi = d(WC(Ti)) / d(Ti).

[0111] The above calculation results are shown in Table 7 - Table 13.

[0112] Table 7 Cp0, Cp7, Cpi

[0113]

[0114]

[0115] Table 8 Ti

[0116] Chlorella pyrenoidosa T1 T3 T5 T7 Ti C.P+R 0.12 0.49 0.85 1.09 0.1635i-0.0165 C.P+R+AZ 0.06 0.31 0.37 1.15 0.1665i-0.1935

[0117] Table 9 C Bi(R-M)

[0118]

[0119] Table 10 C Bi(M)

[0120]

[0121] Table 11 WC i

[0122] Chlorella pyrenoidosa <![CDATA[C1]]> <![CDATA[C3]]> <![CDATA[C5]]> <![CDATA[C7]]> <![CDATA[WC i > C.P+R 0.02 0.04 0.12 0.06 <![CDATA[0.035 + 0.05i - 0.005i 2 > C.P+R+AZ -0.15 0.12 0.05 0.14 <![CDATA[0.24375 + 0.13i - 0.01125i 2 >

[0123] Table 12 WC(Ti), E Bi

[0124] Chlorella pyrenoidosa WC(Ti) C.P+R <![CDATA[0.035+0.05((Ti+0.0165) / 0.1635)-0.005((Ti+0.0165) / 0.1635) 2 > C.P+R+AZ <![CDATA[0.24375+0.13((Ti+0.1935) / 0.1665)-0.01125(((Ti+0.1935) / 0.1665) 2 >

[0125] Table 13 E Bi

[0126] Chlorella pyrenoidosa <![CDATA[E Bi = d(WC(Ti)) / d(Ti)]]> C.P+R -0.06116i+0.3058 C.P+R+AZ -0.1351i+0.7808

[0127] It can be seen from Table 13 that under the two culture conditions of adding AZ and not adding AZ, the weathering of peridotite on the microalgae bio - carbon sequestration effect changes from positive to negative over time. This represents that the weathering of peridotite promotes the increase of microalgae bio - carbon sequestration in the early stage. However, with the continuation of the culture time and the shortage of other nutrients not contained in some rocks, more weathering generates more stress, which has a negative effect on the microalgae carbon sequestration. This is in line with the actual situation. The above - mentioned method for measuring the effect of magnesium - containing rock weathering on microalgae bio - carbon sequestration can be used on the one hand to evaluate the effect of rock weathering on bio - carbon sequestration; on the other hand, it can also be used in carbon sequestration projects to calculate the total carbon sequestration of bio - carbon sequestration and rock weathering carbon sequestration.

[0128] By comparing Table 10 and Table 13, it can be seen that the carbon sequestration effect of the initially grown algae is the strongest. The addition of AZ leads to a greater reduction in the carbon sequestration effect, especially for Chlamydomonas reinhardtii, where the carbon sequestration effect can disappear completely after four days of cultivation. This is because AZ is an inhibitor of extracellular carbonic anhydrase, and the carbonic anhydrase activity of Chlamydomonas reinhardtii is significantly higher than that of Chlorella pyrenoidosa, resulting in Chlamydomonas reinhardtii being more affected by AZ, which is also consistent with the facts.

[0129] The above-described embodiments merely represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the present invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for determining the effect of weathering of magnesium-containing silicate rocks on the microalgae biological carbon sink, characterized in that, Including the following steps: Cultivate two groups of microalgae under the same culture conditions. One group adds magnesium-containing silicate rock and microalgae as the experimental group, and the other group adds only microalgae without adding silicate rock as the blank group; For the blank group, cultivate the microalgae to be tested in the culture medium for i days, measure the chlorophyll a concentration Chi in the culture medium every day, and calculate the photosynthetic carbon concentration C in the blank group at the i time point Bi(M) , where C Bi(M) = 0.74(Chi - Ch0), Ch0 is the chlorophyll a concentration in the culture medium at day 0 of the blank group culture, Chi is the chlorophyll a concentration in the culture medium at day i of the blank group culture, and 0.74 is the mass fraction of carbon content in chlorophyll a; For the experimental group, the microalgae to be tested are cultured in the culture medium for i days, and the magnesium ion concentration Ci and chlorophyll a concentration Cchl-a in the culture medium are measured every day; calculate the photosynthetic carbon concentration C of the experimental treatment group with the addition of silicate rock and microalgae at the i time point Bi(R-M) ; Take the algal bodies cultured for 0 days and T days in the experimental group. After separating the magnesium silicate rock by multiple low-speed centrifugations, measure the chlorophyll a concentration of the algal bodies, transfer the algal bodies into a digestion tank, and use the HNO3 and H2O2 digestion system to digest for a set time at a preset temperature, and measure the magnesium ion concentration C of the digestion solution Mg , and calculate Cpi, Ti, and C respectively Bi(R-M) , where Cpi is the magnesium ion content per unit chlorophyll a of the algal bodies at the i day time point, and Ti is the magnesium ion content from the dissolution of magnesium silicate rock at the i time point; According to the formula WC i =(C Bi(R-M) -C Bi(M) ), the dissolved carbon concentration WC i brought by the weathering of magnesium silicate rocks at time point i in the experimental group is calculated; Dissolved carbon concentration WC i is curve-fitted with the magnesium ion content Ti leached from magnesium-containing silicate rock to obtain the functional relationship WC i (Ti) between WC and Ti; after differentiating the equation WC(Ti) with respect to Ti, the effect E of the weathering of magnesium-containing silicate rock on the microalgae biological carbon sink can be obtained Bi , that is E Bi = d(WC(Ti)) / d(Ti) Among them, the calculation formula of Cpi is: Cpi = Cp0 + i×(Cp T - Cp0) / T where Cp0 is the magnesium ion content per unit chlorophyll a of the thallus on day 0, and Cp T is the magnesium ion content per unit chlorophyll a of the thallus on day T, and is calculated according to the following formula: Cp T = C Mg / Cchl-a The calculation formula of Ti is: Ti = (C i - C0) + (RChi × Cp i - RCh0 × Cp0) wherein, Cp i represents the content of magnesium ions in the chlorophyll a of the algal thallus at the i-th time point; Cp0 represents the content of magnesium ions in the chlorophyll a of the algal thallus at the initial time point, C i is the concentration of magnesium ions in the culture solution at the i-th time point, C0 is the concentration of magnesium ions in the culture solution at the initial time point; RChi is the concentration of chlorophyll a in the culture solution at the i-th time point, and RCh0 is the concentration of chlorophyll a in the culture solution at the initial time point; C Bi(R-M) The calculation formula is as follows: C Bi(R-M) = 0.74(RChi - RCh0) In the formula, RChi is the chlorophyll a concentration in the culture solution at the i time point of the experimental group, and RCh0 is the chlorophyll a concentration in the culture solution at the initial time point of the experimental group.

2. The method for determining the effect of weathering of magnesium-containing silicate rock on the microalgae biological carbon sink according to claim 1, characterized in that The method of separating magnesium silicate rock and microalgae samples by multiple low-speed centrifugations is as follows: Take the mixed sample of the experimental group and place it in a centrifuge tube. After shaking well, set the rotation speed below 500 r / min, centrifuge to collect the supernatant, and discard the precipitate; repeat the low-speed centrifugation of the supernatant twice; take an appropriate amount of the supernatant and centrifuge it at 4000 r / min to collect the algal bodies, add ethanol to extract chlorophyll a and measure the chlorophyll a concentration to obtain Cchl-a; wash the ethanol extraction solution and the precipitate with ethanol, volatilize the ethanol on a hot plate below 80 °C until the last drop, and after cooling, add the HNO3 and H2O2 digestion system for digestion, and measure the magnesium ion concentration C of the digestion solution Mg .

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