Method for regulating and controlling competitive evolution mechanism of marine diatom-dinoflagellate by nutritive salt-enzyme activity

Abstract

The invention belongs to the technical field of marine ecological dynamics and biogeochemical process coupling simulation, and particularly relates to a method for regulating and controlling a marine diatom-dinoflagellate competitive evolution mechanism through nutritive salt-enzyme activity, which comprises the following steps: constructing a model according to a nutritive salt and enzyme activity regulated and controlled double-algae ecological niche competitive principle, introducing an enzyme activity regulation and control sub-module, and constructing a model; the processes of growth, metabolism, secretion, death and the like of phytoplankton are regulated and controlled. The model comprises a nutritive salt module, a phytoplankton module and a debris module which are respectively used for simulating a migration and transformation process of nutritive salt, a growth and disappearance process of phytoplankton and a transformation process of debris in a marine environment. Wherein the absorption, assimilation and transformation processes of nutritive salt are regulated and controlled by enzyme activity, meanwhile, debris is divided into cell debris and granular debris, the organic matter loss and debris mineralization processes of dead cell bodies are distinguished, and the cell disintegration process is supplemented. And finally, simulating phytoplankton growth and digesting kinetic parameters through the model, and analyzing a competitive evolution mechanism of marine diatom and dinoflagellate.

Description

Technical Field

[0001] The present invention belongs to the technical field of coupled simulation of marine ecological dynamics and biogeochemical processes, and particularly relates to a method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity. Background Art

[0002] Coastal ecosystems have important ecological, social and economic values. However, the levels and structures of coastal nutrient salts are constantly changing, which may lead to ecological and environmental problems such as the large-scale reproduction of harmful algal blooms, seasonal hypoxia, and seawater acidification in coastal ecosystems, and are not conducive to the health and sustainable development of coastal ecosystems. The large increase in the discharge of land-source nitrogen and phosphorus into the sea, with the increase in nitrogen nutrient salts far higher than that of phosphorus nutrient salts, has led to significant changes in the levels and structural compositions of nitrogen and phosphorus nutrient salts. These changes not only cause the imbalance of the nitrogen and phosphorus nutrient salt structures, but also make the organic nutrient substances the main form, which promotes the evolution of the marine phytoplankton community structure. Quantitatively analyzing the regulatory effect of the transformation of nutrient salt patterns on the competitive evolution of marine diatoms and dinoflagellates is of great significance for clarifying the evolution trend of the marine phytoplankton community structure and marine ecological protection.

[0003] At present, for the quantitative analysis of the competitive evolution mechanism of marine diatoms and dinoflagellates, ecological dynamics models such as NPZD and CoSiNE are mainly used. Among them, the NPZD model, the full name of which is the Nutrient-Phytoplankton-Zooplankton-Detritus ecological dynamics model, is a classic biogeochemical model used to study the dynamics of marine ecosystems, mainly focusing on the interactions between nutrient salts, phytoplankton, zooplankton, and organic detritus; the CoSiNE model, the full name of which is the Carbon-Silicate-Nitrogen ecological dynamics coupling model, is a kinetic model used to study the relevant connections in the cycling processes of phytoplankton and carbon, silicon, and nitrogen in the marine ecosystem; these ecological dynamics models use relatively simple multiple state variables such as nutrient salts, large algae, small algae, and biological detritus, mainly refining the description of the biogeochemical processes of nutrient salts and plankton; although the above analysis methods classify phytoplankton groups, they lack the regulation of the biogeochemical processes of nutrient salts by extracellular enzymes based on gene control in diatoms and dinoflagellates in the model architecture, and the description of the biogeochemical processes of organic nutrient salts is also not fine enough, making it difficult to accurately and quantitatively analyze the evolution process of diatoms and dinoflagellates in the ocean. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity, which is used to analyze the competitive evolution mechanism of diatoms and dinoflagellates.

[0005] The technical solution adopted by the present invention is as follows: The present invention provides a method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity, comprising the following steps: Construct a box model of diatom-dinoflagellate competitive ecological dynamics regulated by nutrients and enzyme activity, namely the NEDF model. The NEDF model includes a nutrient module, a phytoplankton module, and a detritus module; The nutrient module is used to simulate the migration and transformation process of nutrients in the marine environment; the nutrients are nitrogen nutrients, phosphorus nutrients, and silicon nutrients; nitrogen nutrients are ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, reactive dissolved organic nitrogen, and refractory dissolved organic nitrogen; phosphorus nutrients are reactive phosphate, reactive dissolved organic phosphorus, and refractory dissolved organic phosphorus; silicon nutrients are silicate; The phytoplankton module is used to simulate the growth and decline process of phytoplankton in the marine environment, including a diatom sub-module and a dinoflagellate sub-module; the diatom sub-module includes diatom bioactive nitrogen, diatom bioactive phosphorus, diatom bioactive silicon, and diatom biomass; the dinoflagellate sub-module includes dinoflagellate bioactive nitrogen, dinoflagellate bioactive phosphorus, and dinoflagellate biomass; the phytoplankton includes dinoflagellates and diatoms; The detritus module is used to simulate the process of phytoplankton turning into particulate nitrogen, particulate phosphorus, and particulate silicon in cell detritus after death, as well as the mineralization process; the detritus module includes particulate nitrogen in detritus, particulate phosphorus in detritus, particulate silicon in detritus, particulate nitrogen in diatom cell detritus, particulate phosphorus in diatom cell detritus, particulate nitrogen in dinoflagellate cell detritus, and particulate phosphorus in dinoflagellate cell detritus; Among them, according to the principle of competitive ecological niche of two algae regulated by nutrients and enzyme activity, the NEDF model couples the processes of nutrient absorption, assimilation, and secretion with the photosynthesis-metabolism-death process of phytoplankton, and uses the gene regulation of extracellular enzyme secretion by diatoms and dinoflagellates to regulate the absorption and assimilation processes of dissolved organic nitrogen and phosphorus, and simulates the growth, metabolism, secretion, death, and apoptosis of diatoms and dinoflagellates under different nutrient patterns; By detecting the biomass of phytoplankton, studying the growth and decline process of phytoplankton, further obtaining the dependence degree of phytoplankton on nutrients, and using the NEDF model, analyzing the mechanism of the competitive evolution of diatoms and dinoflagellates under different marine nutrients.

[0006] Preferably, the growth and decline process of phytoplankton in the marine environment is combined with the activity of extracellular enzymes regulated by genes. The ecological niche competition mechanism between diatoms and dinoflagellates includes: Diatoms absorb dissolved inorganic nitrogen, reactive phosphate, and silicate according to the R strategy, and absorb and assimilate reactive dissolved organic nitrogen; Dinoflagellates maintain low growth and death rates according to the K strategy and can also absorb and assimilate refractory dissolved organic nitrogen; The process of diatoms and dinoflagellates absorbing and assimilating dissolved organic nutrients is restricted by enzyme activity regulatory factors. Among them, the activity of dissolved organic nitrogen degrading enzyme is regulated by nitrogen-limitation up-regulation control genes, and the activity of dissolved organic phosphorus degrading enzyme is regulated by phosphorus-limitation up-regulation control genes, and diatoms and dinoflagellates are distinguished.

[0007] Preferably, the method refines the detritus module, and the kinetic processes of the detritus module include the apoptosis process of phytoplankton, the decomposition process of apoptotic cells of phytoplankton, and the microbial degradation process of particulate nitrogen and phosphorus in detritus.

[0008] Preferably, the nutrient module constructs a nutrient biogeochemical module according to the bioavailability of nutrients and by introducing enzyme activity regulation factors. The biogeochemical processes of the nutrients include the nitrogen migration and transformation process, the phosphorus migration and transformation process, and the silicon migration and transformation process. The nitrogen migration and transformation process includes the oxidation of ammonium nitrogen, the nitrification of nitrite nitrogen, the enzyme-controlled absorption and assimilation process of reactive dissolved organic nitrogen, the enzyme-controlled secretion process of reactive dissolved organic nitrogen, the degradation process of reactive dissolved organic nitrogen, the enzyme-controlled absorption and assimilation process of refractory dissolved organic nitrogen, the enzyme-controlled secretion process of refractory dissolved organic nitrogen, and the degradation process of refractory dissolved organic nitrogen. The phosphorus migration and transformation process includes the enzyme-controlled absorption and assimilation process of reactive dissolved organic phosphorus, the enzyme-controlled secretion process of reactive dissolved organic phosphorus, the degradation process of reactive dissolved organic phosphorus, and the degradation process of refractory dissolved organic phosphorus. The silicon migration and transformation process includes the absorption and degradation process of silicate.

[0009] Preferably, the nitrogen migration and transformation process includes the oxidation process of ammonium nitrogen, the nitrification process of nitrite nitrogen, the degradation process of dissolved organic nitrogen, the humification process of dissolved organic nitrogen, and the remineralization process of particulate nitrogen in detritus. The phosphorus migration and transformation process includes the degradation process of dissolved organic phosphorus, the humification process of dissolved organic phosphorus, and the remineralization process of particulate phosphorus in detritus. The silicon migration and transformation process is the absorption of silicate and the degradation of particulate matter.

[0010] Preferably, the oxidation process of ammonium nitrogen is as follows: ; The nitrification process of nitrite nitrogen is as follows: ; The degradation process of dissolved organic nitrogen is as follows: ; The humification process of dissolved organic nitrogen is as follows: ; The remineralization process of particulate nitrogen in detritus is as follows: ; The degradation process of dissolved organic phosphorus is as follows: ; The humification process of dissolved organic phosphorus is as follows: ; The remineralization process of particulate phosphorus in detritus is as follows: ; The absorption of silicate and the degradation of particulate matter are as follows: ; wherein, is the ammonium nitrogen oxidation rate constant; is the temperature limitation coefficient; is the ammonium nitrogen concentration; is the nitrification rate constant; is the nitrite nitrogen concentration; is the maximum rate constant for the degradation of active dissolved organic nitrogen to ammonium nitrogen; is the active dissolved organic nitrogen concentration; is the inert dissolved organic nitrogen concentration; is the maximum rate constant for the conversion of active dissolved organic nitrogen to inert dissolved organic nitrogen; is the detrital particulate phosphorus decomposition rate constant; is the phytoplankton detrital particulate nitrogen concentration; is the labile particulate nitrogen fraction in phytoplankton detritus; is the maximum rate constant for the degradation of active dissolved organic phosphorus to inorganic phosphorus; is the active dissolved organic phosphorus concentration; is the inert dissolved organic phosphorus concentration; is the maximum rate constant for the conversion of active dissolved organic phosphorus to inert dissolved organic phosphorus; is the detrital particulate phosphorus decomposition rate constant; is the phytoplankton detrital particulate phosphorus concentration; is the labile particulate phosphorus fraction in phytoplankton detritus; is the maximum silicate uptake rate constant; is the diatom nitrogen limitation coefficient; is the diatom inorganic phosphorus limitation coefficient; is the light limitation coefficient; is the phytoplankton particulate silicon concentration; is the silicon migration and transformation rate constant.

[0011] Preferably, the generation and elimination process includes a growth process, a respiration process, a secretion process, and a death process.

[0012] Preferably, the growth process of diatoms is ; The respiration process of diatoms ; The secretion process of diatoms is ; The death process of diatoms is ; wherein, is the maximum diatom growth rate constant at 0°C; The maximum enzyme-controlled secretion rate constant of diatoms at 0°C; is the maximum death rate constant of diatoms at 0°C; is the nitrogen limitation coefficient of diatoms; is the phosphorus limitation coefficient of diatoms; is the silicon limitation coefficient; is the light limitation coefficient; is the temperature limitation coefficient; is the respiration rate coefficient of diatoms; is the carbon-nitrogen ratio limitation coefficient of diatoms; is the enzyme activity regulation coefficient of diatoms; is the biomass of diatoms.

[0013] Preferably, the growth process of dinoflagellates is ; The respiration process of dinoflagellates is ; The secretion process of dinoflagellates is ; The death process of dinoflagellates is ; Among them, is the maximum growth rate constant of dinoflagellates at 0°C; is the maximum enzyme-controlled secretion rate constant of dinoflagellates at 0°C; is the maximum death rate constant of dinoflagellates at 0°C; is the nitrogen limitation coefficient of dinoflagellates; is the phosphorus limitation coefficient of dinoflagellates; is the light limitation coefficient; is the temperature limitation coefficient; is the respiration rate coefficient of dinoflagellates; is the carbon-nitrogen ratio limitation coefficient of dinoflagellates; is the enzyme activity regulation coefficient of dinoflagellates; is the biomass of dinoflagellates.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a method for regulating the competitive evolution mechanism of marine diatoms-dinoflagellates by nutrient-enzyme activity, comprising the following steps: Construct an NEDF model, the NEDF model includes a nutrient module, a phytoplankton module and a detritus module; The nutrient module is used to simulate the migration and transformation process of nutrients in the marine environment; the nutrients are nitrogen nutrients, phosphorus nutrients and silicon nutrients; nitrogen nutrients are ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, reactive dissolved organic nitrogen and inert dissolved organic nitrogen; phosphorus nutrients are reactive phosphate, reactive dissolved organic phosphorus and inert dissolved organic phosphorus; silicon nutrients are silicate; The phytoplankton module is used to simulate the growth and decay process of phytoplankton in the marine environment, including a diatom sub-module and a dinoflagellate sub-module; the diatom sub-module includes diatom bioactive nitrogen, diatom bioactive phosphorus, diatom bioactive silicon and diatom biomass; the dinoflagellate sub-module includes dinoflagellate bioactive nitrogen, dinoflagellate bioactive phosphorus and dinoflagellate biomass; the phytoplankton includes dinoflagellates and diatoms; The detritus module is used to simulate the process of phytoplankton turning into particulate nitrogen, particulate phosphorus and particulate silicon of cell detritus after death, as well as the mineralization process; the detritus module includes particulate nitrogen of detritus, particulate phosphorus of detritus, particulate silicon of detritus, particulate nitrogen of diatom cell detritus, particulate phosphorus of diatom cell detritus, particulate nitrogen of dinoflagellate cell detritus and particulate phosphorus of dinoflagellate cell detritus; Among them, according to the principle of dual-algae niche competition regulated by nutrients and enzyme activity, the NEDF model couples the processes of nutrient uptake, assimilation and secretion with the photosynthesis-metabolism-death process of phytoplankton, and uses the genes of diatoms and dinoflagellates to regulate the secretion of extracellular enzymes to regulate the uptake and assimilation processes of dissolved organic nitrogen and phosphorus, and simulates the growth, metabolism, secretion, death and apoptosis of diatoms and dinoflagellates under different nutrient patterns; By detecting the biomass of phytoplankton, studying the growth and decay process of phytoplankton, further obtaining the dependence degree of phytoplankton on nutrients, and using the NEDF model, analyzing the mechanism of the competition evolution between diatoms and dinoflagellates under different marine nutrients.

[0015] A method for regulating the competition evolution mechanism of marine diatoms-dinoflagellates by nutrients and enzyme activity according to the present invention describes the changes of phytoplankton through the dynamic interaction of four modules of nutrients-diatoms-dinoflagellates-detritus. Nutrients include nitrogen nutrients, phosphorus nutrients and silicon nutrients. Phytoplankton grows by absorbing and assimilating nutrients, while nutrients also have a limiting effect on the growth of phytoplankton. Due to the differences in the preference for nutrient structure and growth strategies of different phytoplankton, competition and succession occur. Diatoms have a high affinity for inorganic nitrogen and can dominate the environment rich in inorganic nitrogen; while dinoflagellates adapt to the limiting environment of high nitrogen-phosphorus ratio by converting and utilizing organic nutrients. Detritus realizes the remineralization process of nutrients through processes such as microbial decomposition, releases organic nutrients back into the water body to form a regeneration cycle, and phytoplankton will also be converted into detritus through death processes, dissolution processes, etc.

[0016] Compared with the traditional NPZD model, the NEDF model of the present invention removes the zooplankton module, modifies the phytoplankton module and introduces a competition mechanism between two types of algae. The phytoplankton is divided into diatoms and dinoflagellates, and their growth, metabolism, death and other processes are simulated respectively. The nutrient module is not simply divided into dissolved inorganic nitrogen, dissolved organic nitrogen, dissolved inorganic phosphorus and dissolved organic phosphorus; instead, DIN is divided into NH4-N, NO3-N and NO2-N; DON is divided into LDON and RDON; DIP is PO4-P; DOP is divided into LDOP and RDOP. Moreover, the detritus module is refined, and the detritus is divided into phytoplankton cell detritus and particulate detritus, the loss of organic matter in dead cell bodies and the process of detritus mineralization are distinguished, and the process of cell disintegration is supplemented.

[0017] In the NEDF model of the present invention, diatoms rapidly absorb dissolved inorganic nitrogen, reactive phosphate and silicate according to the R strategy; dinoflagellates maintain low growth and death rates according to the K strategy, and they can absorb all forms of nitrogen, PO4 and LDOP. The processes of diatoms and dinoflagellates absorbing and assimilating dissolved organic nutrients are restricted by enzyme activity regulatory factors. Among them, the activity of dissolved organic nitrogen degrading enzymes such as leucine aminopeptidase is regulated by nitrogen-limitation up-regulation control genes, and the activity of dissolved organic phosphorus degrading enzymes such as alkaline phosphatase is regulated by phosphorus-limitation up-regulation control genes, and diatoms and dinoflagellates are distinguished. The absorption strategy adopts the principle of competitive absorption. In addition, the processes of respiration, metabolism and secretion are subdivided in the growth and decay process of phytoplankton. The respiration process and the secretion process are combined into one item and reflected as the proportion item of photosynthesis, and the C, N, P metabolic secretion processes regulated by enzyme activity are supplemented. The larger the proportion of RDON, under the condition of environmental nitrogen deficiency, the nitrogen metabolism and photosynthesis genes of diatoms and dinoflagellate cells are up-regulated, the nitrogen-related extracellular enzyme activity increases, the metabolic rate increases, and the secretion of cell DON and DOC is promoted; for dinoflagellates, the metabolic secretion process under the condition of RDOP limitation is supplemented, that is, the larger the proportion of RDOP, under the condition of environmental phosphorus deficiency, the phosphorus metabolism genes of cells are up-regulated, the phosphorus-related extracellular enzyme activity increases, the metabolic rate increases, and the secretion of cell DOP is promoted.

[0018] The NEDF model of the present invention describes the biogeochemical processes of marine nutrients and the competition and evolution mechanism between diatoms and dinoflagellates more precisely and comprehensively, the logical framework is more perfect, and it is closer to the actual ecosystem. By introducing physiological responses and molecular biological mechanisms, the present invention reveals the driving mechanism of the evolution of the phytoplankton community structure in the Bohai Sea, and provides a scientific basis and application value for the prediction of harmful algal blooms in the Bohai Sea and the health assessment of the ecosystem. Description of the Drawings

[0019] Figure 1The simulation results of phytoplankton and nutrients. a: Chlorophyll simulation results of phytoplankton growth and death; b: Absorption, migration and transformation curve of phosphorus nutrients; c: Absorption, migration and transformation curve of nitrogen nutrients; d: Absorption, migration and transformation curve of silicon nutrients.

[0020] Figure 2 The logical architecture of the nutrient - enzyme activity regulated diatom - dinoflagellate competition ecological dynamics box model described in the present invention. Specific implementation manners

[0021] The present invention is further described below through specific examples, but the scope of the present invention is not limited thereby. Modifications or substitutions can be made to the details and forms of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but these modifications or substitutions all fall within the protection scope of the present invention.

[0022] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention is further described below in conjunction with specific examples. In the description of the present invention, unless otherwise specified, the reagents used are commercially available and the methods used are conventional techniques in the art.

[0023] The abbreviation list of the present invention is shown in Table 1.

[0024] Table 1 Abbreviation list

[0025] Example 1 A method for analyzing the competitive evolution mechanism of marine nutrients - diatoms - dinoflagellates is as follows: The present invention constructs an NEDF model, where the Chinese name of the NEDF model is the nutrient - enzyme activity regulated diatom - dinoflagellate competition ecological dynamics box model.

[0026] The construction process of the NEDF model includes: 1. Construction of the phytoplankton module. Phytoplankton includes the diatom module and the dinoflagellate module, and these two modules belong to the growth and decay process of phytoplankton.

[0027] ; (1a) is the diatom growth kinetic equation, which represents the change of diatom biomass. PDB is the diatom biomass, and the right side of the equation includes the growth process, respiration process, enzyme - controlled secretion process and death process of diatoms; where is the change in biomass of the growth process; is the change in biomass of the respiration process; is the change in biomass of the enzyme - controlled secretion process; is the change in biomass of the death process.

[0028] (1b) is the growth kinetic equation of dinoflagellates, representing the change in dinoflagellate biomass. PFB is the dinoflagellate biomass. The right side of the equation includes the growth process, respiration process, enzyme-controlled secretion process, and death process of dinoflagellates: among them, is the change in biomass during the growth process; is the change in biomass during the respiration process; is the change in biomass during the enzyme-controlled secretion process; is the change in biomass during the death process.

[0029] The growth processes of diatoms and dinoflagellates are affected by temperature and light limitation conditions. The ecological models of the prior art lack the quantification of the respiration process and the secretion process. The present invention reflects the respiration process and the secretion process as the proportion terms of photosynthesis to refine the carbon cycle process inside phytoplankton.

[0030] ; ; (2a) to (2e) are the diatom nitrogen uptake kinetic equation, dinoflagellate nitrogen uptake kinetic equation, diatom phosphorus uptake kinetic equation, dinoflagellate phosphorus uptake kinetic equation, and diatom silicon uptake kinetic equation in sequence. The changes in the biomass of dinoflagellates and diatoms are represented by the changes in different particulate forms of nitrogen and phosphorus in phytoplankton. The material flow of the change in different particulate forms of nitrogen in phytoplankton is molN, and the material flow of the change in phosphorus is molP. The content in the brackets in the formulas of (2a) to (2e) represents the migration and transformation rates of different forms of nutrients inside and outside the phytoplankton cells. Taking as an example: the change in particulate nitrogen during the diatom absorption process: ; the change in particulate nitrogen during the diatom metabolism process: ; the change in particulate nitrogen during the diatom enzyme-controlled secretion process: ; the change in particulate nitrogen during the diatom death process: . Due to the changes in the form and composition of nutrients caused by the growth, respiration, metabolism, and death processes of phytoplankton, the present invention adds an enzyme-controlled nutrient secretion process to better express the absorption and utilization process of organic nutrients by the enzyme activities of diatoms and dinoflagellates. represents the ratio of nitrogen to chlorophyll, represents the ratio of phosphorus to chlorophyll. Among them, PDN, PFN, PDP, PFP, and PDSi use the ratio of biomass to nutrients for the unit conversion of carbon-nitrogen-phosphorus-silicon material flow, has no association with the particulate nitrogen and phosphorus of phytoplankton in this model.

[0031] The relevant light and temperature limitation coefficients in the equation are as follows: ; The photosynthesis of phytoplankton is mainly limited by temperature, light, and nutrients, where temperature is represented in a given exponential form. Light mainly comes from solar radiation, but only a part of the radiation is absorbed by phytoplankton in the ocean surface layer and converted into photosynthetically active radiation. In the model, the light limitation coefficient is calculated from the photosynthetically active radiation and the optimal photosynthetically active radiation. In the equation is the light limitation coefficient; is the temperature limitation coefficient; is the maximum light intensity; is the optimal light intensity, C is a constant, T is the temperature, which represents different environmental factors in the following equation.

[0032] The nitrogen-related limitation coefficients are as follows: ; ; represents the nitrogen-related limitation coefficient, where represent the DON enzyme activity regulatory factor, the nitrogenase activity limitation coefficient of diatoms, and the nitrogenase activity limitation coefficient of dinoflagellates, respectively; represents the activity of the dissolved organic nitrogen degrading enzyme; represent the minimum concentration thresholds of NH4-N and NO3-N, respectively; represents different nitrogen-related half-saturation constants; the form of the enzyme activity-related equation is obtained by linear fitting using culture experiment data through the Michaelis-Menten equation, etc. , are the fitting-related parameters, and the relevant equations in the following text are the same.

[0033] The phosphorus-related limitation coefficients are as follows: ; The growth and absorption processes of phytoplankton are also regulated by nutrient limitation, including the limitation of inorganic nitrogen, inorganic phosphorus, silicate, organic nitrogen, and organic phosphorus. On the basis of the above model, an enzyme activity regulatory factor was further introduced into the organic nutrient limitation term. represents the dissolved organic phosphorus-related limitation coefficient, where represents the dissolved organic phosphorus enzyme activity regulatory factor; represents the activity of the dissolved organic phosphorus degrading enzyme; 、 、 、 represents different phosphorus-related half-saturation constants.

[0034] The silicon-related limitation coefficients are as follows: ; wherein represents the silicon-limited half-saturation constant.

[0035] The other limiting coefficients are as follows: ; represents the phytoplankton nitrogen-phosphorus ratio limiting coefficient to regulate the phytoplankton secretion process; represents the phytoplankton carbon-nitrogen ratio limiting coefficient to regulate the phytoplankton secretion process; , represents the phytoplankton enzyme activity regulation coefficient to regulate the phytoplankton secretion process; 、 、 、 represents the nitrogen-phosphorus ratio and carbon-nitrogen ratio limiting coefficients; , , represents the maximum enzyme-controlled secretion rate constant; 、 、 represents the enzyme activity correction coefficient.

[0036] 2. Construction of the nutrient module, i.e., the nutrient transfer process.

[0037] ; ; ; Equations (8a) to (8e) are the migration and transformation kinetic equations of nitrogen nutrients, which are the migration and transformation kinetic equations of NH4-N, NO2-N, NO3-N, LDON, and RDON in sequence. Equations (8a) to (8e) include the oxidation process of NH4-N: ; The nitrification process of NO2-N: ; The degradation process of DON: ; The humification process of DON: ; The remineralization process of particulate detrital nitrogen: . The process of phytoplankton absorbing nutrients is restricted by light and temperature and regulated by enzyme activity; while the migration and transformation of nitrogen nutrients are regulated by temperature. Wherein 、 、 、 is the nitrogen migration and transformation rate constant, 、 is the proportion of bioavailable organic nitrogen and the proportion of bioavailable components in detritus.

[0038] ; ; Equations (9a) to (9c) are the migration and transformation kinetic equations of phosphorus nutrients, which are the migration and transformation kinetic equation of PO4-P, the migration and transformation kinetic equation of LDOP, and the migration and transformation kinetic equation of RDOP in sequence. Equation (9d) is the migration and transformation kinetic equation of silicon nutrients, which mainly includes the degradation process of DOP: ; the humification process of DOP: ; the remineralization process of particulate nutrient phosphorus: . The process of phytoplankton absorbing phosphorus nutrients is related to light limitation and temperature limitation conditions, while the migration and transformation of phosphorus nutrients are restricted by temperature limitation conditions. Among them 、 is the phosphorus migration and transformation rate constant, 、 is the proportion of reactive organic phosphorus and the proportion of reactive and easily degradable components in detritus.

[0039] Regarding the model of the silicon nutrient migration and transformation process, the processes of silicate absorption and particulate degradation are adopted, is the silicon migration and transformation rate constant.

[0040] 3. Construction of the detritus module.

[0041] ; Equations (10a) to (10g) are the DDN kinetic equation, the PDDN kinetic equation, the PFDN kinetic equation, the DDP kinetic equation, the PDDP kinetic equation, the PFDP kinetic equation, and the DDSi PD kinetic equation in sequence. Equations (10a) to (10g) represent detritus in different particulate forms of phytoplankton. In the present invention, the diatom detrital particulate nitrogen in mainstream ecological kinetic models such as NPZD is divided into diatom cell detrital particulate nitrogen and phytoplankton detrital particulate nitrogen; the diatom detrital particulate phosphorus is divided into diatom cell detrital particulate phosphorus and phytoplankton detrital particulate phosphorus; the dinoflagellate detrital particulate nitrogen is divided into dinoflagellate cell detrital particulate nitrogen and phytoplankton detrital particulate nitrogen; the dinoflagellate detrital particulate phosphorus is divided into dinoflagellate cell detrital particulate phosphorus and phytoplankton detrital particulate phosphorus. Among them and and The detritus area is refined into two parts: the intermediate process in which phytoplankton cells decompose into dead detritus cell bodies and the detritus, in order to distinguish the process of organic matter release by the decomposition of dead cell bodies from the mineralization process of detritus. represents the dead detritus cell bodies of phytoplankton, which is the intermediate process of forming detritus. Its unstable decomposition and mineralization result in detritus and organic nutrients. This is consistent with what some literature has proposed, considering a constant mortality rate or a mortality rate related to the cell's nutritional status, to explain that once cell lysis occurs, there will be a contribution of cells to DOM and to particulate organic matter POM. Among them, the decomposition rate constant related to phytoplankton detritus particulate state: 、 、 、 。 represents the rate constant of silicon migration and transformation. The detritus-related processes in this subsection are restricted by temperature conditions.

[0042] The glossary of terms for the model described in the present invention is shown in Table 2.

[0043] Table 2 Glossary of Model Terms

[0044] The model described in the present invention was simulated and analyzed on the ModelMaker 4.0 platform. The observational data from the in-situ enclosure experiment in Laizhou Bay in 2022 were used for simulation. The observational data on the first day were used as the initial input values for the model, as shown in Table 3. The simulated annealing algorithm combined with Marquardt nonlinear regression was used for parameter optimization. The final optimization goal was to minimize the simulation deviation of total nitrogen, total phosphorus, and silicate concentrations, as Figure 1 shown, and the relevant kinetic parameters in Tables 4 and 5 were finally obtained.

[0045] Table 3 Initial Input Values for the Model

[0046] Figure 1 are the simulation results of the phytoplankton and nutrient salt model. Figure 1 In a of : The black dashed line is the simulated value of the diatom biomass model, and the black circular dots are the measured values of the diatom biomass; the red dashed line is the simulated value of the dinoflagellate biomass model, and the red square dots are the measured values of the dinoflagellate biomass. Figure 1 In b of : The black dashed line is the simulated value of the PO4 model, and the black square dots are the measured values of PO4; the blue dashed line is the simulated value of the DOP model, and the blue circular dots are the measured values of DOP; the red dashed line is the simulated value of the particulate phosphorus model, and the red triangular dots are the measured values of particulate phosphorus. Figure 1In c: The black dashed line is the simulated value of the NH4 model, and the black square points are the measured values of NH4; the red dashed line is the simulated value of the NO3 model, and the red triangle points are the measured values of NO3; the blue dashed line is the simulated value of the DON model, and the blue dot points are the measured values of DON; the green dashed line is the simulated value of the particulate nitrogen model, and the green downward triangle points are the measured values of particulate nitrogen. Figure 1 In d: The black dashed line is the simulated value of the SiO3 model, and the black square points are the measured values of SiO3. Figure 1 The shaded area in the figure represents the standard deviation of the model variables.

[0047] Table 4 Diatom and Dinoflagellate Kinetic Parameters - 1

[0048] Table 5 Diatom and Dinoflagellate Kinetic Parameters - 2

[0049] In Tables 4 and 5, "-" indicates the absence of this item.

[0050] There are regional differences in the community structure of marine phytoplankton. Different regions and different species have different response mechanisms to nutrients and adaptation mechanisms to environmental factors. There is still a lack of precise quantitative analysis methods for the steady-state transformation of the dominant phytoplankton population from diatoms to dinoflagellates and the related nutrient action mechanisms in the Bohai Sea. The present invention constructs an NEDF model to quantitatively analyze the transformation of the dominant phytoplankton population in the Bohai Sea and the related nutrient action mechanisms. The NEDF model includes four major modules: a nutrient module, a diatom module, a dinoflagellate and detritus module; it is composed of 23 state variables including ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, reactive dissolved organic nitrogen, refractory dissolved organic nitrogen, inorganic phosphorus, reactive dissolved organic phosphorus, refractory dissolved organic phosphorus, silicate, particulate nitrogen of diatom phytoplankton, particulate nitrogen of dinoflagellate phytoplankton, particulate nitrogen of diatom cell debris, particulate nitrogen of dinoflagellate cell debris, particulate nitrogen of detritus, particulate phosphorus of diatom phytoplankton, particulate phosphorus of dinoflagellate phytoplankton, particulate phosphorus of diatom cell debris, particulate phosphorus of dinoflagellate cell debris, particulate phosphorus of detritus, particulate silicon of diatom phytoplankton, particulate silicon of detritus, diatom phytoplankton and dinoflagellate phytoplankton, as shown in Figure 2 .

[0051] Figure 2This is the logical architecture of the NEDF model of the present invention, where (1) represents the microbial degradation of dissolved organic nitrogen; (2) represents the oxidation of NH4-N; (3) represents the nitrification of NO2-N; (4) represents the conversion of reactive dissolved organic nitrogen to refractory dissolved organic nitrogen; (5) represents the absorption process and growth process of phytoplankton regulated by enzyme activity; (6) represents the metabolic process of phytoplankton, represented by particulate phytoplankton; (7) represents the death process of phytoplankton, represented by particulate phytoplankton; (8) represents the degradation of dead algal cells into detritus; (9) represents the lysis and release of dead algal cells; (10) represents the microbial degradation of detritus; (11) represents the microbial degradation of dissolved organic phosphorus; (12) represents the conversion of reactive dissolved organic phosphorus to refractory dissolved organic phosphorus.

[0052] On the one hand, the NEDF model of the present invention couples the processes of nutrient uptake, assimilation, and secretion with the photosynthesis-metabolism-death processes of phytoplankton. On the other hand, considering the representativeness of regionality and interdecadal evolution, as well as the coupling of physiological response and molecular biology, it combines the absorption and assimilation of organic matter by extracellular enzyme activity under gene control, and quantitatively analyzes the kinetic parameters of the growth, metabolism, death processes of diatoms-dinoflagellates in the Bohai Sea and the nutrient uptake, assimilation, and secretion processes under different nutrient patterns.

[0053] Subsequently, based on the marine nutrient-diatom-dinoflagellate competition-detritus ecological dynamics model, the present invention obtains the relevant parameters such as the growth and death of phytoplankton and their uptake of nutrients, and analyzes the parameter changes under different conditions; through the changes in light, temperature, and nutrient structure in different decades, it conducts simulation analysis to clarify the nutrient-driven mechanism of the community structure evolution of diatoms-dinoflagellates in the Bohai Sea, providing a basis for further clarifying the steady-state transformation mechanism of the phytoplankton community structure in the Bohai Sea.

[0054] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0055] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the 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 be made, and these all belong to the protection scope of the present invention.

Claims

1. A method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity, characterized in that It includes the following steps: Construct a box model of nutrient - enzyme activity regulated diatom - dinoflagellate competition ecological dynamics. The box model of nutrient - enzyme activity regulated diatom - dinoflagellate competition ecological dynamics includes a nutrient module, a phytoplankton module, and a detritus module; The nutrient module is used to simulate the migration and transformation process of nutrients in the marine environment; the nutrients are nitrogen nutrients, phosphorus nutrients, and silicon nutrients; nitrogen nutrients include ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, reactive dissolved organic nitrogen, and refractory dissolved organic nitrogen; phosphorus nutrients include reactive phosphate, reactive dissolved organic phosphorus, and refractory dissolved organic phosphorus; silicon nutrients are silicate; The phytoplankton module is used to simulate the growth and decay process of phytoplankton in the marine environment, including a diatom sub - module and a dinoflagellate sub - module; the diatom sub - module contains diatom bioactive nitrogen, diatom bioactive phosphorus, diatom bioactive silicon, and diatom biomass; the dinoflagellate sub - module contains dinoflagellate bioactive nitrogen, dinoflagellate bioactive phosphorus, and dinoflagellate biomass; the phytoplankton includes dinoflagellates and diatoms; The detritus module is used to simulate the process of phytoplankton turning into particulate nitrogen, particulate phosphorus, and particulate silicon of cell detritus after death, as well as the mineralization process; the detritus module contains particulate nitrogen of detritus, particulate phosphorus of detritus, particulate silicon of detritus, particulate nitrogen of diatom cell detritus, particulate phosphorus of diatom cell detritus, particulate nitrogen of dinoflagellate cell detritus, and particulate phosphorus of dinoflagellate cell detritus; Among them, the box model of nutrient - enzyme activity regulated diatom - dinoflagellate competition ecological dynamics is based on the principle of dual - algal niche competition regulated by nutrients and enzyme activity. It couples the processes of nutrient absorption, assimilation, and secretion with the photosynthesis - metabolism - death process of phytoplankton, and uses the gene regulation of extracellular enzyme secretion by diatoms and dinoflagellates to regulate the absorption and assimilation process of dissolved organic nitrogen and phosphorus, simulating the growth, metabolism, secretion, death, and apoptosis processes of diatoms and dinoflagellates under different nutrient patterns; By detecting the biomass of phytoplankton, studying the growth and decay process of phytoplankton, further obtaining the dependence degree of phytoplankton on nutrients, and using the box model of nutrient - enzyme activity regulated diatom - dinoflagellate competition ecological dynamics, analyze the mechanism of the competition evolution between diatoms and dinoflagellates under different marine nutrients.

2. The method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity according to claim 1, wherein The growth and decay process of phytoplankton in the marine environment is combined with the activity of extracellular enzymes regulated by genes. The ecological niche competition mechanism between diatoms and dinoflagellates includes: Diatoms absorb dissolved inorganic nitrogen, reactive phosphate, and silicate according to the R - strategy, and absorb and assimilate reactive dissolved organic nitrogen; Dinoflagellates maintain low growth and death rates according to the K - strategy and can also absorb and assimilate refractory dissolved organic nitrogen; The process of diatoms and dinoflagellates absorbing and assimilating dissolved organic nutrients is restricted by enzyme activity regulatory factors. Among them, the activity of dissolved organic nitrogen - degrading enzyme is regulated by nitrogen - limitation up - control genes, and the activity of dissolved organic phosphorus - degrading enzyme is regulated by phosphorus - limitation up - control genes, and diatoms and dinoflagellates are distinguished.

3. The method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity according to claim 1, characterized in that The method refines the detritus module, and the kinetic process of the detritus module is the apoptosis process of phytoplankton, the decomposition process of apoptotic phytoplankton cells, and the microbial degradation process of particulate nitrogen and phosphorus in detritus.

4. The method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity according to claim 1, wherein The nutrient module constructs a nutrient biogeochemical module according to the bioavailability of nutrients and introduces an enzyme activity regulation factor. The biogeochemical processes of the nutrients are nitrogen migration and transformation processes, phosphorus migration and transformation processes, and silicon migration and transformation processes; The nitrogen migration and transformation processes include ammonium nitrogen oxidation, nitrite nitrogen nitrification, enzyme-controlled absorption and assimilation processes of active dissolved organic nitrogen, enzyme-controlled secretion processes of active dissolved organic nitrogen, degradation processes of active dissolved organic nitrogen, enzyme-controlled absorption and assimilation processes of inert dissolved organic nitrogen, enzyme-controlled secretion processes of inert dissolved organic nitrogen, and degradation processes of inert dissolved organic nitrogen; The phosphorus migration and transformation processes include enzyme-controlled absorption and assimilation processes of active dissolved organic phosphorus, enzyme-controlled secretion processes of active dissolved organic phosphorus, degradation processes of active dissolved organic phosphorus, and degradation processes of inert dissolved organic phosphorus; The silicon migration and transformation process is the absorption and degradation process of silicate; 5. The method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity according to claim 4, characterized in that The nitrogen migration and transformation processes include the oxidation process of ammonium nitrogen, the nitrification process of nitrite nitrogen, the degradation process of dissolved organic nitrogen, the humification process of dissolved organic nitrogen, and the remineralization process of detrital particulate nitrogen; The phosphorus migration and transformation processes include the degradation process of dissolved organic phosphorus, the humification process of dissolved organic phosphorus, and the remineralization process of detrital particulate phosphorus; The silicon migration and transformation process is the absorption of silicate and the degradation process of particulate silicon; 6. The method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity according to claim 5, characterized in that The oxidation process of the ammonium nitrogen is as follows: ; The nitrification process of nitrite nitrogen is as follows: ; The degradation process of dissolved organic nitrogen is as follows: ; The humification process of dissolved organic nitrogen is as follows: ; The remineralization process of particulate nitrogen is as follows: ; The degradation process of the dissolved organic phosphorus is as follows: ; The humification process of dissolved organic phosphorus is as follows: ; The remineralization process of particulate phosphorus is as follows: ; The absorption of silicate and the degradation process of particulate silicon are as follows: ； wherein, is the ammonium nitrogen oxidation rate constant; is the temperature limitation coefficient; is the ammonium nitrogen concentration; is the nitrification rate constant; is the nitrite nitrogen concentration; is the maximum rate constant for the degradation of reactive dissolved organic nitrogen to ammonium nitrogen; is the reactive dissolved organic nitrogen concentration; is the inert dissolved organic nitrogen concentration; is the maximum rate constant for the conversion of reactive dissolved organic nitrogen to inert dissolved organic nitrogen; is the detrital particulate phosphorus decomposition rate constant; is the phytoplankton detrital particulate nitrogen concentration; is the labile particulate nitrogen fraction in phytoplankton detritus; is the maximum rate constant for the degradation of reactive dissolved organic phosphorus to inorganic phosphorus; is the reactive dissolved organic phosphorus concentration; is the inert dissolved organic phosphorus concentration; is the maximum rate constant for the conversion of reactive dissolved organic phosphorus to inert dissolved organic phosphorus; is the detrital particulate phosphorus decomposition rate constant; is the phytoplankton detrital particulate phosphorus concentration; is the labile particulate phosphorus fraction in phytoplankton detritus; is the maximum silicate absorption rate constant; is the diatom nitrogen limitation coefficient; is the diatom inorganic phosphorus limitation coefficient; is the light limitation coefficient; is the phytoplankton particulate silicon concentration; is the silicon migration and transformation rate constant.

7. The method for regulating the competitive evolution mechanism of nutrients-enzymatic activity in marine diatoms-dinoflagellates according to claim 1, characterized in that The growth and decay processes include the growth process, the respiration process, the secretion process, and the death process.

8. The method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient salts and enzyme activity according to claim 7, characterized in that The growth process of diatoms is ; Respiration process of diatoms ; The secretion process of diatoms is ; The death process of diatoms is ; Among them, is the maximum growth rate constant of diatoms at 0°C; is the maximum enzyme-controlled secretion rate constant of diatoms at 0°C; is the maximum death rate constant of diatoms at 0°C; is the nitrogen limitation coefficient of diatoms; is the phosphorus limitation coefficient of diatoms; is the silicon limitation coefficient; is the light limitation coefficient; is the temperature limitation coefficient; is the respiration rate coefficient of diatoms; is the carbon-nitrogen ratio limitation coefficient of diatoms; is the enzyme activity regulation coefficient of diatoms; is the diatom biomass.

9. The method for regulating the competitive evolution mechanism of nutrient - enzyme activity in marine diatoms - dinoflagellates according to claim 7, characterized in that, The growth process of dinoflagellates is ; The respiration process of dinoflagellates is ; The secretion process of dinoflagellates is ; The death process of dinoflagellates is ; Among them, is the maximum growth rate constant of dinoflagellates at 0°C; is the maximum enzyme-controlled secretion rate constant of dinoflagellates at 0°C; is the maximum death rate constant of dinoflagellates at 0°C; is the nitrogen limitation coefficient of dinoflagellates; is the phosphorus limitation coefficient of dinoflagellates; is the light limitation coefficient; is the temperature limitation coefficient; is the respiration rate coefficient of dinoflagellates; is the carbon-nitrogen ratio limitation coefficient of dinoflagellates; is the enzyme activity regulation coefficient of dinoflagellates; is the biomass of dinoflagellates.

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