Method for regulating evolution mechanism of marine diatom and dinoflagellate competition by nutrient salt-enzyme activity

Abstract

The present application belongs to the field of marine ecological dynamics and biogeochemical process coupling simulation technology, and particularly relates to a method for regulating marine diatom-microzooplankton competition evolution mechanism by nutrient salt-enzyme activity, comprising the following steps: constructing a model according to the double-algae niche competition principle of nutrient salt and enzyme activity regulation, introducing an enzyme activity regulation submodule, and regulating the growth, metabolism, secretion and death processes of phytoplankton. The model comprises a nutrient salt module, a phytoplankton module and a detritus module, which are respectively used for simulating the migration and transformation process of nutrient salt in the marine environment, the growth and death process of phytoplankton and the transformation process of detritus. The absorption, assimilation and transformation processes of nutrient salt are regulated by enzyme activity, and the detritus is divided into cell detritus and particulate detritus, so as to distinguish the loss of dead cell organic matter and the mineralization process of detritus, and the cell disintegration process is supplemented. Finally, the phytoplankton growth and death dynamics parameters are simulated by the model, and the mechanism of marine diatom-microzooplankton competition evolution is analyzed.

Description

Technical Field

[0001] This invention belongs to the field of coupled simulation technology of marine ecological dynamics and biogeochemical processes, specifically involving a method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates by nutrient-enzyme activity. Background Technology

[0002] Nearshore ecosystems possess significant ecological and socioeconomic value. However, the constantly changing levels and structure of nutrients in nearshore waters can lead to ecological and environmental problems such as the proliferation of harmful algal blooms, seasonal hypoxia, and seawater acidification, hindering the health and sustainable development of nearshore ecosystems. The substantial increase in land-based nitrogen and phosphorus emissions into the ocean, with nitrogen nutrient increases far exceeding phosphorus nutrient increases, has resulted in significant changes in nitrogen and phosphorus nutrient levels and composition. These changes not only lead to an imbalance in nitrogen and phosphorus nutrient structure but also make organic nutrients the dominant form, driving the evolution of marine phytoplankton community structure. Quantitatively analyzing the regulatory role of nutrient pattern changes in the evolution of marine diatom-dinoflagellate competition is crucial for elucidating the evolutionary trends of marine phytoplankton community structure and for marine ecological conservation.

[0003] Currently, quantitative analysis of the competitive evolutionary mechanisms of marine diatoms and dinoflagellates mainly employs ecodynamic models such as NPZD and CoSiNE. The NPZD model, short for Nutrient-Phytoplankton-Zooplankton-Detritus Ecodynamic Model, is a classic biogeochemical model used to study the dynamics of marine ecosystems, primarily focusing on the interactions between nutrients, phytoplankton, zooplankton, and organic detritus. The CoSiNE model, short for Carbon-Silicate-Nitrogen Ecodynamic Coupled Model, is a dynamic model used to study the relationship between phytoplankton and the cycling processes of carbon, silicon, and nitrogen in marine ecosystems. These ecodynamic models use relatively simple state variables such as nutrients, macroalgae, microalgae, and biodetritus, mainly refining the description of the biogeochemical processes of nutrients and phytoplankton. Although these analytical methods classify phytoplankton groups, their model architecture lacks the regulation of nutrient biogeochemical processes by extracellular enzymes controlled by genes in diatoms and dinoflagellates, and the description of the biogeochemical processes of organic nutrients is not refined enough, making it difficult to accurately quantify and analyze the evolutionary processes of diatoms and dinoflagellates in the ocean. Summary of the Invention

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

[0005] The technical solution adopted in this invention is:

[0006] This 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:

[0007] A box model of diatom-dinoflagellate competition dynamics regulated by nutrient-enzyme activity was constructed, namely the NEDF model. The NEDF model includes a nutrient module, a phytoplankton module, and a detritus module.

[0008] The nutrient module is used to simulate the migration and transformation processes of nutrients in the marine environment; the nutrients are nitrogen nutrients, phosphorus nutrients, and silicon nutrients; the nitrogen nutrients are ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, active dissolved organic nitrogen, and inert dissolved organic nitrogen; the phosphorus nutrients are active phosphate, active dissolved organic phosphorus, and inert dissolved organic phosphorus; the silicon nutrients are silicates.

[0009] The phytoplankton module is used to simulate the life and death processes of phytoplankton in the marine environment, and includes a diatom submodule and a dinoflagellate submodule; the diatom submodule contains diatom bioactive nitrogen, diatom bioactive phosphorus, diatom bioactive silicon and diatom biomass; the dinoflagellate submodule contains dinoflagellate bioactive nitrogen, dinoflagellate bioactive phosphorus and dinoflagellate biomass; the phytoplankton includes dinoflagellates and diatoms;

[0010] The debris module is used to simulate the process of phytoplankton death transforming into particulate nitrogen, particulate phosphorus, and particulate silicon in cell debris, as well as the mineralization process. The debris module includes particulate nitrogen, particulate phosphorus, particulate silicon, particulate nitrogen from diatom cell debris, particulate phosphorus from diatom cell debris, particulate nitrogen from dinoflagellates, and particulate phosphorus from dinoflagellates.

[0011] The NEDF model, based on the principle of dual algal niche competition regulated by nutrients and enzyme activity, couples the processes of nutrient absorption, assimilation, and secretion with the photosynthetic-metabolic-death processes of phytoplankton. It also utilizes the genes of diatoms and dinoflagellates to regulate the secretion of extracellular enzymes to control the absorption and assimilation of dissolved organic nitrogen and phosphorus, thus simulating the growth, metabolism, secretion, death, and apoptosis of diatoms and dinoflagellates under different nutrient configurations.

[0012] By detecting phytoplankton biomass, we can study the phytoplankton growth and decay processes, further understand the dependence of phytoplankton on nutrients, and use the NEDF model to analyze the mechanism of competitive evolution between diatoms and dinoflagellates under different marine nutrient conditions.

[0013] Preferably, the biodiversity and decomposition processes of phytoplankton in the marine environment are combined with gene-regulated extracellular enzyme activity, and the niche competition mechanism between the diatoms and dinoflagellates includes:

[0014] Diatoms absorb and dissolve inorganic nitrogen, reactive phosphates and silicates according to the R strategy, and absorb and assimilate reactive dissolved organic nitrogen.

[0015] Dinoflagellates maintain low growth and death rates according to the K strategy and can also absorb and assimilate inert dissolved organic nitrogen;

[0016] The process by which diatoms and dinoflagellates absorb, assimilate, and dissolve organic nutrients is limited by enzyme activity regulators. Specifically, the activity of nitrogen-degrading enzymes is regulated by nitrogen-limiting ascending control genes, and the activity of phosphorus-degrading enzymes is regulated by phosphorus-limiting ascending control genes. This distinguishes between diatoms and dinoflagellates.

[0017] Preferably, the method refines the debris module, and the kinetic process of the debris module is the phytoplankton apoptosis process, the phytoplankton apoptotic cell decomposition process, and the microbial degradation process of nitrogen and phosphorus in debris particles.

[0018] Preferably, the nutrient module is a nutrient biogeochemical module structured according to the bioavailability of nutrients and by introducing enzyme activity regulatory factors. The biogeochemical processes of the nutrients are nitrogen migration and transformation processes, phosphorus migration and transformation processes, and silicon migration and transformation processes.

[0019] The nitrogen migration and transformation processes are: ammonium nitrogen oxidation, nitrite nitrogen nitrification, enzyme-controlled absorption and assimilation of active dissolved organic nitrogen, enzyme-controlled secretion of active dissolved organic nitrogen, degradation of active dissolved organic nitrogen, enzyme-controlled absorption and assimilation of inert dissolved organic nitrogen, enzyme-controlled secretion of inert dissolved organic nitrogen, and degradation of inert dissolved organic nitrogen.

[0020] The phosphorus migration and transformation process includes the enzymatically controlled absorption and assimilation of active soluble organophosphates, the enzymatically controlled secretion of active soluble organophosphates, the degradation of active soluble organophosphates, and the degradation of inert soluble organophosphates.

[0021] The silicon migration and transformation process is a process of silicate absorption and degradation.

[0022] 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 detrital particulate nitrogen;

[0023] 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 detrital particulate phosphorus.

[0024] The silicon migration and transformation process is a process of silicate absorption and particulate degradation.

[0025] Preferably, the oxidation process of the ammonium nitrogen is as follows: ;

[0026] The nitrification process of nitrite is as follows: ;

[0027] The degradation process of dissolved organic nitrogen is as follows: ;

[0028] The humification process of dissolved organic nitrogen is as follows: ;

[0029] The remineralization process of particulate nitrogen in detritus is as follows: ;

[0030] The degradation process of the dissolved organophosphorus is as follows: ;

[0031] The humification process of dissolved organophosphorus compounds is as follows: ;

[0032] The remineralization process of detrital particulate phosphorus is as follows: ;

[0033] The silicate absorption and particulate degradation process is as follows:

[0034] ;

[0035] in, The rate constant for ammonium nitrogen oxidation; This is the temperature limiting factor; This refers to the ammonium nitrogen concentration; This is the nitration rate constant; Nitrite concentration; The maximum rate constant for the degradation of active dissolved organic nitrogen into ammonium nitrogen; The concentration of active dissolved organic nitrogen; This refers to the concentration of inert dissolved organic nitrogen. The maximum rate constant for the conversion of active dissolved organic nitrogen into inert dissolved organic nitrogen; The decomposition rate constant of phosphorus in detrital particles; This refers to the concentration of particulate nitrogen in phytoplankton debris. It is an easily degradable particulate nitrogen component in phytoplankton debris; The maximum rate constant for the degradation of active dissolved organic phosphorus into inorganic phosphorus; This refers to the concentration of actively dissolved organophosphorus compounds. This refers to the concentration of inert dissolved organophosphorus compounds. The maximum rate constant for the conversion of active dissolved organophosphorus phosphorus into inert dissolved organophosphorus phosphorus; The constant for the phosphorus decomposition rate of detrital particles; This refers to the concentration of particulate phosphorus in phytoplankton debris. It is an easily degradable particulate phosphorus component in phytoplankton debris; This is the maximum absorption rate constant of silicates; The nitrogen limitation factor for diatoms; The inorganic phosphorus limitation factor for diatoms; The light confinement factor; This refers to the concentration of particulate silicon in phytoplankton. is the silicon migration conversion rate constant.

[0036] Preferably, the life-death process includes a growth process, a respiration process, a secretion process, and a death process.

[0037] Preferably, the growth process of diatoms is as follows: ;

[0038] Diatom respiration ;

[0039] The secretion process of diatoms is as follows ;

[0040] The death process of diatoms is as follows ;

[0041] in, This is the maximum growth rate constant of diatoms at 0℃; The maximum enzyme-controlled secretion rate constant of diatoms at 0℃; This is the maximum mortality rate constant of diatoms at 0℃; The nitrogen limitation factor for diatoms; The diatom phosphorus limitation factor; The silicon limitation factor; The light confinement factor; This is the temperature limiting factor; This is the diatom respiration rate coefficient; The carbon-to-nitrogen ratio limitation coefficient for diatoms; The diatomase activity regulatory coefficient; This refers to diatom biomass.

[0042] Preferably, the growth process of dinoflagellates is as follows: ;

[0043] The respiration process of dinoflagellates is ;

[0044] The secretion process of dinoflagellates is as follows ;

[0045] The death process of dinoflagellates is as follows ;

[0046] in, The maximum growth rate constant of dinoflagellates at 0℃; This is the constant of the maximum enzyme-controlled secretion rate of dinoflagellates at 0℃; This is the maximum mortality rate constant of dinoflagellates at 0℃; The nitrogen limitation factor for dinoflagellates; The phosphorus limitation coefficient for dinoflagellates; The light confinement factor; This is the temperature limiting factor; This is the respiration rate coefficient of dinoflagellates; The carbon-to-nitrogen ratio limiting factor for dinoflagellates; This is the regulatory coefficient for dinoflagellate enzyme activity; This refers to the biomass of dinoflagellates.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] This 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:

[0049] Construct a NEDF model, which includes a nutrient module, a phytoplankton module, and a detritus module;

[0050] The nutrient module is used to simulate the migration and transformation processes of nutrients in the marine environment; the nutrients are nitrogen nutrients, phosphorus nutrients, and silicon nutrients; the nitrogen nutrients are ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, active dissolved organic nitrogen, and inert dissolved organic nitrogen; the phosphorus nutrients are active phosphate, active dissolved organic phosphorus, and inert dissolved organic phosphorus; the silicon nutrients are silicates.

[0051] The phytoplankton module is used to simulate the life and death processes of phytoplankton in the marine environment, and includes a diatom submodule and a dinoflagellate submodule; the diatom submodule contains diatom bioactive nitrogen, diatom bioactive phosphorus, diatom bioactive silicon and diatom biomass; the dinoflagellate submodule contains dinoflagellate bioactive nitrogen, dinoflagellate bioactive phosphorus and dinoflagellate biomass; the phytoplankton includes dinoflagellates and diatoms;

[0052] The debris module is used to simulate the process of phytoplankton death transforming into particulate nitrogen, particulate phosphorus, and particulate silicon in cell debris, as well as the mineralization process. The debris module includes particulate nitrogen, particulate phosphorus, particulate silicon, particulate nitrogen from diatom cell debris, particulate phosphorus from diatom cell debris, particulate nitrogen from dinoflagellates, and particulate phosphorus from dinoflagellates.

[0053] The NEDF model, based on the principle of dual algal niche competition regulated by nutrients and enzyme activity, couples the processes of nutrient absorption, assimilation, and secretion with the photosynthetic-metabolic-death processes of phytoplankton. It also utilizes the genes of diatoms and dinoflagellates to regulate the secretion of extracellular enzymes to control the absorption and assimilation of dissolved organic nitrogen and phosphorus, thus simulating the growth, metabolism, secretion, death, and apoptosis of diatoms and dinoflagellates under different nutrient configurations.

[0054] By detecting phytoplankton biomass, we can study the phytoplankton growth and decay processes, further understand the dependence of phytoplankton on nutrients, and use the NEDF model to analyze the mechanism of competitive evolution between diatoms and dinoflagellates under different marine nutrient conditions.

[0055] This invention describes a method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates through nutrient-enzyme activity. It constructs a NEDF model to describe phytoplankton changes through the dynamic interactions of four modules: nutrients, diatoms, dinoflagellates, and detritus. Nutrients include nitrogen, phosphorus, and silicon nutrients. Phytoplankton grow by absorbing and assimilating nutrients, while nutrients also limit their growth. Due to differences in nutrient structure preferences and growth strategies among different phytoplankton species, competition and succession occur. Diatoms have a high affinity for inorganic nitrogen and can dominate environments rich in inorganic nitrogen; while dinoflagellates adapt to environments with high nitrogen-to-phosphorus ratios by converting and utilizing organic nutrients. Detritus undergoes nutrient remineralization through microbial decomposition and other processes, releasing organic nutrients back into the water to form a regenerative cycle. Phytoplankton also transform into detritus through death and dissolution processes.

[0056] Compared to the traditional NPZD model, the NEDF model of this invention removes the zooplankton module and modifies the phytoplankton module to introduce a dual-algal competition mechanism, classifying phytoplankton into diatoms and dinoflagellates, and simulating their growth, metabolism, and death processes 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 into LDON and RDON; DIP into PO4-P; and DOP into LDOP and RDOP. Furthermore, the debris module is refined, dividing debris into phytoplankton cell debris and particulate debris, distinguishing between the loss of organic matter from dead cells and the mineralization process of debris, and supplementing the cell disintegration process.

[0057] In the NEDF model of this invention, diatoms rapidly absorb and dissolve inorganic nitrogen, reactive phosphates, and silicates according to strategy R; dinoflagellates maintain low growth and mortality rates according to strategy K, and can absorb all forms of nitrogen, PO4, and LDOP. The process of diatoms and dinoflagellates absorbing and assimilating dissolved organic nutrients is limited by enzyme activity regulators. For example, the activity of leucine aminopeptidase, an enzyme that dissolves organic nitrogen, is regulated by nitrogen-limited ascending control genes, and the activity of alkaline phosphatase, an enzyme that dissolves organic phosphorus, is regulated by phosphorus-limited ascending control genes, thus distinguishing between diatoms and dinoflagellates. The absorption strategy adopts a competitive absorption principle. Furthermore, the biodiversity of phytoplankton was further subdivided into respiration, metabolism, and secretion processes. The respiration and secretion processes were combined into one item and reflected as the proportion of photosynthesis. The C, N, and P metabolism and secretion processes regulated by enzyme activity were added. Under nitrogen-deficient environmental conditions, diatoms and dinoflagellates upregulated nitrogen metabolism and photosynthesis genes, increased nitrogen-related extracellular enzyme activity, enhanced metabolic rate, and promoted the secretion of DON and DOC. For dinoflagellates, the metabolic and secretion processes under RDOP restriction conditions were added. That is, under phosphorus-deficient environmental conditions, cells upregulated phosphorus metabolism genes, increased phosphorus-related extracellular enzyme activity, enhanced metabolic rate, and promoted the secretion of DOP.

[0058] The NEDF model of this invention provides a more refined and comprehensive description of marine nutrient biogeochemical processes and the competitive evolution mechanism of diatoms and dinoflagellates, with a more complete logical framework and a closer resemblance to actual ecosystems. By introducing physiological responses and molecular biological mechanisms, this invention reveals the driving mechanism of phytoplankton community structure evolution in the Bohai Sea, providing a scientific basis and application value for predicting harmful algal blooms and assessing ecosystem health in the Bohai Sea. Attached Figure Description

[0059] Figure 1 The simulation results for phytoplankton and nutrients are as follows: a: chlorophyll simulation results for phytoplankton growth and death; b: absorption and migration transformation curves of phosphorus nutrients; c: absorption and migration transformation curves of nitrogen nutrients; d: absorption and migration transformation curves of silicon nutrients.

[0060] Figure 2 This is the logical architecture of the box model of nutrient-enzyme-regulated diatom-dinoflagellate competitive ecological dynamics described in this invention. Detailed Implementation

[0061] The present invention will be further illustrated below with specific embodiments, but these embodiments do not limit the scope of the invention. Modifications or substitutions to the details and form of the technical solutions of the present invention may be made without departing from the spirit and scope of the invention, but all such modifications or substitutions fall within the protection scope of the present invention.

[0062] To enable those skilled in the art to better understand and implement the technical solutions of this invention, the invention will be further described below with reference to specific embodiments. In the description of this invention, unless otherwise specified, all reagents used are commercially available, and all methods used are conventional techniques in the art.

[0063] The list of abbreviations for this invention is shown in Table 1.

[0064] Table 1 List of Abbreviations

[0065]

[0066] Example 1

[0067] A method for analyzing the competitive evolution mechanism of marine nutrients, diatoms, and dinoflagellates is as follows:

[0068] This invention constructs a NEDF model, where NEDF stands for Nutrient-Enzyme Activity Regulated Diatom-Dinoflagellate Competition Ecodynamics Box Model.

[0069] The process of constructing a NEDF model includes:

[0070] 1. Construction of the phytoplankton module: Phytoplankton includes the diatom module and the dinoflagellate module. These two modules belong to the phytoplankton biogenesis and decomposition process.

[0071] ;

[0072] (1a) is the diatom growth kinetic equation, representing the change in diatom biomass. PDB The equation represents diatom biomass, and the right side includes the diatom's growth, respiration, enzyme-controlled secretion, and death processes; among which, This refers to changes in biomass during the growth process; This refers to changes in biomass during respiration. This refers to the biomass changes during the enzyme-controlled secretion process; This refers to the biomass changes during the death process.

[0073] (1b) is the kinetic equation for the growth of dinoflagellates, representing the change in dinoflagellate biomass. PFB The equation represents the biomass of dinoflagellates, and the right side includes the growth, respiration, enzyme-controlled secretion, and death processes of the dinoflagellates: where, This refers to changes in biomass during the growth process; This refers to changes in biomass during respiration. This refers to the biomass changes during the enzyme-controlled secretion process; This refers to the biomass changes during the death process.

[0074] The growth processes of diatoms and dinoflagellates are influenced by temperature and light limiting conditions. Existing ecological models lack quantification of respiration and secretion processes. This invention refines the carbon cycle processes within phytoplankton by representing respiration and secretion processes as a proportion of photosynthesis.

[0075] ;

[0076] ;

[0077] Equations (2a) to (2e) represent the kinetic equations for nitrogen absorption by diatoms, nitrogen absorption by dinoflagellates, phosphorus absorption by diatoms, phosphorus absorption by dinoflagellates, and silicon absorption by diatoms, respectively. The changes in nitrogen and phosphorus content in phytoplankton of different particle forms are used to represent the changes in biomass of dinoflagellates and diatoms. The mass flow of nitrogen changes in phytoplankton of different particle forms is represented by molN, and the mass flow of phosphorus changes is represented by molP. The contents in parentheses in equations (2a) to (2e) represent the migration and transformation rates of different forms of nutrients inside and outside phytoplankton cells. For example: Changes in particulate nitrogen during diatom absorption: Changes in particulate nitrogen during diatom metabolism: ;

[0078] Changes in particulate nitrogen during diatom enzymatic secretion: Changes in particulate nitrogen during diatom death: Because the growth, respiration, metabolism, and death processes of phytoplankton lead to changes in the form and composition of nutrients, this invention adds an enzyme-controlled nutrient secretion process to better express the absorption and utilization of organic nutrients by diatoms and dinoflagellates. The ratio of nitrogen to chlorophyll. The ratio of phosphorus to chlorophyll represents the total phosphorus content. PDN, PFN, PDP, PFP, and PDSi are represented by the ratio of biomass to nutrients, indicating the unit transformation of carbon-nitrogen-phosphorus-silicon mass flow. There is no correlation between particulate nitrogen and phosphorus in phytoplankton and this model.

[0079] The relevant illumination and temperature limiting coefficients in the equation are as follows:

[0080] ;

[0081] Phytoplankton photosynthesis is primarily limited by temperature, light, and nutrients, with temperature expressed as a given exponential factor. Light mainly comes from solar radiation, but only a portion of this radiation is absorbed by surface-dwelling phytoplankton and converted into photosynthetically active radiation. In the model, the light limitation factor is calculated using photosynthetically active radiation and optimal photosynthetically active radiation. In the equations... The light confinement factor; This is the temperature limiting factor; This represents the maximum light intensity. For optimal light intensity, C It is a constant. T Here, temperature represents a different environmental factor than in the equation below.

[0082] The nitrogen-related limitation coefficients are as follows:

[0083] ;

[0084] ;

[0085] Represents the nitrogen-related limitation coefficient, where These represent the DON enzyme activity regulatory factor, diatom nitrogenase activity restriction coefficient, and dinoflagellate nitrogenase activity restriction coefficient, respectively. Represents the activity of enzymes that degrade dissolved organic nitrogen; These represent the minimum concentration thresholds for NH4-N and NO3-N, respectively. These represent different nitrogen-related half-saturation constants; the enzyme activity-related equations are obtained using linear fitting techniques such as the Michaelis-Menten equation based on culture experiment data. , To fit the relevant parameters, the correlation equations in the following text are the same.

[0086] The relevant phosphorus limitation coefficients are as follows:

[0087] ;

[0088] Phytoplankton growth and absorption are also regulated by nutrient limitation, including limitations on inorganic nitrogen, inorganic phosphorus, silicates, organic nitrogen, and organic phosphorus. Building upon the above model, enzyme activity regulators were further introduced into the organic nutrient limitation term. Represents the limiting coefficient related to dissolved organophosphorus compounds, where Representative of factors regulating the activity of organophosphorus lysing enzymes; Represents the activity of enzymes that dissolve organophosphorus compounds; 、 、 、 These represent the half-saturation constants associated with different forms of phosphorus.

[0089] The silicon-related constraint factors are as follows:

[0090] ;

[0091] in This represents the silicon-limited half-saturation constant.

[0092] Other limiting factors are as follows:

[0093] ;

[0094] The nitrogen-to-phosphorus ratio limiting coefficient of phytoplankton is used to regulate the secretion process of phytoplankton; The carbon-to-nitrogen ratio limiting coefficient of phytoplankton is used to regulate the secretion process of phytoplankton; , The coefficient representing the regulatory factor of phytoplankton enzyme activity is used to regulate the secretion process of phytoplankton. 、 、 、 Represents the limiting factors for the nitrogen-to-phosphorus ratio and the carbon-to-nitrogen ratio; , , Represents the maximum enzyme-controlled secretion rate constant; 、 、 This represents the enzyme activity correction coefficient.

[0095] 2. The construction of the nutrient module, i.e. the nutrient migration process.

[0096] ;

[0097] ;

[0098] ;

[0099] (8a) to (8e) are the kinetic equations for the migration and transformation of nitrogen nutrients, namely, the kinetic equations for NH4-N, NO2-N, NO3-N, LDON, and RDON, respectively. (8a) to (8e) include the oxidation process of NH4-N: The nitration process of NO2-N: The degradation process of DON: The humification process of DON: Detrital particulate nitrogen remineralization process: The process of phytoplankton nutrient absorption is limited by light and temperature and regulated by enzyme activity; while the migration and transformation of nitrogen nutrients are regulated by temperature. 、 、 、 The nitrogen migration and conversion rate constant is 、 The percentage of bioavailable organic nitrogen and the percentage of bioavailable components in debris.

[0100] ;

[0101] ;

[0102] (9a)~(9c) are the migration and transformation kinetic equations for phosphorus nutrients, namely the PO4-P migration and transformation kinetic equation, the LDOP migration and transformation kinetic equation, and the RDOP migration and transformation kinetic equation, respectively. (9d) is the migration and transformation kinetic equation for silicon nutrients, mainly including 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- and temperature-limited conditions, while the migration and transformation of phosphorus nutrients are limited by temperature-limited conditions. 、 The phosphorus migration and conversion rate constant is... 、 The percentage of active organic phosphorus and the percentage of active and easily degradable components in the debris.

[0103] The model for the migration and transformation of silicon nutrients employed a process involving silicate absorption and particulate degradation. is the silicon migration conversion rate constant.

[0104] 3. Construction of the debris module.

[0105] ;

[0106] (10a)~(10g) are, in order, the kinetic equations of DDN, PDDN, PFDN, DDP, PDDP, PFDP, and DDSi. PD Kinetic equations. (10a)~(10g) represent detritus in different particle forms of phytoplankton. In this invention, the particulate nitrogen of diatom debris in mainstream ecological kinetic models such as NPZD is divided into particulate nitrogen of diatom cell debris and particulate nitrogen of phytoplankton debris; particulate phosphorus of diatom debris is divided into particulate phosphorus of diatom cell debris and particulate phosphorus of phytoplankton debris; particulate nitrogen of dinoflagellates is divided into particulate nitrogen of dinoflagellates and particulate nitrogen of phytoplankton debris; and particulate phosphorus of dinoflagellates is divided into particulate phosphorus of dinoflagellates and particulate phosphorus of phytoplankton debris. and and The detrital zone is further subdivided into two parts: the intermediate process of phytoplankton cell decomposition into dead detrital cell bodies and the detrital material itself. This distinguishes the process of releasing organic matter from the decomposition of dead cell bodies from the mineralization process of the detrital material. The dead phytoplankton cell bodies represent the intermediate process of detrital formation, undergoing unstable decomposition and mineralization into detrital material and organic nutrients. This aligns with some literature suggesting the consideration of a constant mortality rate or a mortality rate related to cellular nutritional status to explain the contribution of cells to the DOM (detrital organic matter) and to particulate organic matter (POM) once cell lysis occurs. The phytoplankton detrital particulate decomposition rate constant is as follows: 、 、 、 . This represents the silicon migration conversion rate constant. The debris-related processes in this section are subject to temperature-limited conditions.

[0107] The glossary of terms for the model described in this invention is shown in Table 2.

[0108] Table 2. Explanation of Model Terms

[0109]

[0110] The model described in this invention was simulated and analyzed on the ModelMaker 4.0 platform. Observational data from a field isolation experiment in Laizhou Bay in 2022 were used for simulation, with the first day's observational data as the initial input values ​​(see Table 3). Simulated annealing combined with Marquardt nonlinear regression was used for parameter optimization. The final optimization objective was to minimize the simulation bias of total nitrogen, total phosphorus, and silicate concentrations. Figure 1 As shown, the relevant dynamic parameters are finally obtained in Tables 4 and 5.

[0111] Table 3 Initial values ​​of model input

[0112]

[0113] Figure 1 The simulation results are for the phytoplankton and nutrient model. Figure 1 In section a: the black dashed line represents the simulated value of diatom biomass model, and the black circular dots represent the measured value of diatom biomass; the red dashed line represents the simulated value of dinoflagellate biomass model, and the red square dots represent the measured value of dinoflagellate biomass. Figure 1In b: the black dashed line represents the simulated value of PO4 model, and the black square dot represents the measured value of PO4; the blue dashed line represents the simulated value of DOP model, and the blue dot represents the measured value of DOP; the red dashed line represents the simulated value of particulate phosphorus model, and the red triangle dot represents the measured value of particulate phosphorus. Figure 1 In c: the black dashed line represents the simulated value of NH4 model, and the black square dot represents the measured value of NH4; the red dashed line represents the simulated value of NO3 model, and the red triangle dot represents the measured value of NO3; the blue dashed line represents the simulated value of DON model, and the blue circle dot represents the measured value of DON; the green dashed line represents the simulated value of particulate nitrogen model, and the green lower triangle dot represents the measured value of particulate nitrogen. Figure 1 In d: the black dashed line represents the simulated value of SiO3 model, and the black square dot represents the measured value of SiO3. Figure 1 The shaded area represents the standard deviation of the model variables.

[0114] Table 4. Dynamic parameters of diatoms and dinoflagellates - 1

[0115]

[0116] Table 5. Dynamic parameters of diatoms and dinoflagellates - 2

[0117]

[0118] In Tables 4 and 5, "-" indicates that this item is not present.

[0119] Marine phytoplankton community structure varies geographically, and different regions and 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 transition of the dominant phytoplankton population in the Bohai Sea from diatoms to dinoflagellates and the related nutrient action mechanisms. This invention uses a NEDF model to analyze and quantify the shift in dominant phytoplankton populations and the related nutrient mechanisms in the Bohai Sea. The NEDF model comprises four modules: nutrient modules, diatom modules, dinoflagellates, and detritus modules. It consists of 23 state variables: ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, active dissolved organic nitrogen, inert dissolved organic nitrogen, inorganic phosphorus, active dissolved organic phosphorus, inert dissolved organic phosphorus, silicates, diatom phytoplankton particulate nitrogen, dinoflagellate phytoplankton particulate nitrogen, diatom cell debris particulate nitrogen, dinoflagellate cell debris particulate nitrogen, detritus particulate nitrogen, diatom phytoplankton particulate phosphorus, dinoflagellate phytoplankton particulate phosphorus, diatom cell debris particulate phosphorus, dinoflagellate cell debris particulate phosphorus, detritus particulate phosphorus, diatom phytoplankton particulate silicon, detritus particulate silicon, diatom phytoplankton, and dinoflagellate phytoplankton. (See [link to NEDF model]). Figure 2 .

[0120] Figure 2The logical architecture of the NEDF model described in this invention is as follows: (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 active dissolved organic nitrogen into inert dissolved organic nitrogen; (5) represents the absorption 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 biodebris; (9) represents the dissolution and release of dead algal cells; (10) represents the microbial degradation of biodebris; (11) represents the microbial degradation of dissolved organic phosphorus; and (12) represents the conversion of active dissolved organic phosphorus into inert dissolved organic phosphorus.

[0121] The NEDF model of this invention couples the processes of nutrient absorption, assimilation, and secretion with the photosynthetic-metabolic-death processes of phytoplankton. On the other hand, considering the representativeness of regional 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. This model quantifies and analyzes the kinetic parameters of the growth, metabolism, and death processes of diatoms and dinoflagellates in the Bohai Sea under different nutrient patterns, as well as the processes of nutrient absorption, assimilation, and secretion.

[0122] Next, this invention uses a marine nutrient-diatom-dinoflagellate competition-detrital ecodynamic model to obtain relevant parameters such as phytoplankton growth and death and nutrient absorption, and analyzes the parameter changes under different conditions. Through simulation analysis of changes in light, temperature and nutrient structure over different years, the nutrient-driven mechanism of the evolution of the diatom-dinoflagellate community structure in the Bohai Sea is elucidated, providing a foundation for further elucidating the steady-state transformation mechanism of the phytoplankton community structure in the Bohai Sea.

[0123] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection 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, Includes the following steps: A box model of diatom-dinoflagellate competitive ecological dynamics regulated by nutrient salts and enzyme activity was constructed. The box model of diatom-dinoflagellate competitive ecological dynamics regulated by nutrient salts and enzyme activity includes a nutrient salt 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; the nitrogen nutrients are ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, active dissolved organic nitrogen and inert dissolved organic nitrogen; the phosphorus nutrients are active phosphate, active dissolved organic phosphorus and inert dissolved organic phosphorus; the silicon nutrients are silicates; the nutrient module includes the migration and transformation kinetic equations (8a)~(8e) of nitrogen nutrients, the migration and transformation kinetic equations (9a)~(9c) of phosphorus nutrients and the migration and transformation kinetic equation (9d) of silicon nutrients. The phytoplankton module, used to simulate the growth and decay processes of phytoplankton in the marine environment, includes a diatom submodule and a dinoflagellate submodule. The diatom submodule contains diatom biomass, diatom phytoplankton particulate nitrogen, diatom phytoplankton particulate phosphorus, and diatom phytoplankton particulate silicon. The dinoflagellate submodule contains dinoflagellate biomass, dinoflagellate phytoplankton particulate nitrogen, and dinoflagellate phytoplankton particulate phosphorus. The phytoplankton includes dinoflagellates and diatoms. The phytoplankton module includes the diatom growth kinetic equation (1a), the dinoflagellate growth kinetic equation (1b), the diatom nitrogen absorption kinetic equation (2a), the dinoflagellate nitrogen absorption kinetic equation (2b), the diatom phosphorus absorption kinetic equation (2c), the dinoflagellate phosphorus absorption kinetic equation (2d), and the diatom silicon absorption kinetic equation (2e). The debris module is used to simulate the process of phytoplankton death transforming into particulate nitrogen, particulate phosphorus, and particulate silicon in cellular debris, as well as the mineralization process. The debris module includes particulate nitrogen, particulate phosphorus, particulate silicon, particulate nitrogen from diatom cell debris, particulate phosphorus from diatom cell debris, particulate nitrogen from dinoflagellates, and particulate phosphorus from dinoflagellates. The debris module includes the kinetic equations for particulate nitrogen from phytoplankton (10a), particulate nitrogen from diatom cell debris (10b), particulate nitrogen from dinoflagellates (10c), particulate phosphorus from phytoplankton (10d), particulate phosphorus from diatom cell debris (10e), particulate phosphorus from dinoflagellates (10f), and particulate silicon from diatom cell debris (10g). The nutrient-enzyme-regulated diatom-dinoflagellate competitive ecological dynamics box model 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 photosynthetic-metabolic-death processes of phytoplankton, and uses the genes of diatoms and dinoflagellates to regulate the secretion of extracellular enzymes to regulate the absorption and assimilation of dissolved organic nitrogen and phosphorus, thus simulating the growth, metabolism, secretion, death, and apoptosis processes of diatoms and dinoflagellates under different nutrient configurations. By detecting phytoplankton biomass, we studied the phytoplankton growth and decay processes, further obtained the degree of phytoplankton dependence on nutrients, and used a box model of diatom-dinoflagellate competition dynamics regulated by nutrient-enzyme activity to analyze the mechanism of diatom-dinoflagellate competition evolution under different marine nutrient conditions. In the above dynamic equations: It is the maximum absorption rate constant of nitrogen. It is the maximum nitrogen-controlled secretion rate constant at 0℃. It is the nitrogen respiration rate coefficient of phytoplankton. It is the maximum rate constant for the degradation of LDON into RDON. It is the maximum rate constant for the degradation of LDON into NH4. It is the rate constant for the release of organic nitrogen through cell lysis. It is the nitrogen decomposition rate constant of detrital particles. It is the rate constant of nitrogen decomposition of phytoplankton particles. It is the ammonium oxidation rate constant. It is the nitration rate constant. It is the maximum absorption rate constant of phosphorus. It is the maximum enzyme-controlled secretion rate constant of phosphorus at 0℃. It is the phosphorus respiration rate coefficient of phytoplankton. It is the maximum rate constant for the degradation of LDOP into RDOP. It is the maximum rate constant for the degradation of LDOP into PO4. It is the rate constant for the release of organophosphates through cell lysis. It is the rate constant of phosphorus decomposition of debris particles. It is the rate constant of phosphorus decomposition of phytoplankton particles. It is the maximum absorption rate constant of silicon. It is the rate constant of silicon decomposition of phytoplankton particles. It is the maximum growth rate constant of phytoplankton at 0℃. It is the maximum mortality rate constant of phytoplankton at 0℃. It is the maximum enzyme-controlled secretion rate constant at 0℃. It is the phytoplankton respiration rate coefficient, It is the N:Chla ratio. It is the P:Chla ratio. It is the rate constant of cell degradation of dead cells. It is the proportion of bioavailable organic nitrogen in detritus degradation. It is the proportion of bioavailable organic phosphorus in detritus degradation. It is an easily degradable particulate nitrogen component in phytoplankton detritus. It is an easily degradable particulate phosphorus component in phytoplankton debris. It is the silicon migration conversion rate constant. ammonium nitrogen oxidation rate constant, ammonium nitrogen concentration, Nitrite concentration, The maximum rate constant for the degradation of active dissolved organic nitrogen into ammonium nitrogen. To determine the concentration of active dissolved organic nitrogen, For inert dissolved organic nitrogen concentration, The maximum rate constant for the conversion of active dissolved organic nitrogen to inert dissolved organic nitrogen. The rate constant for the decomposition of particulate phosphorus, For the concentration of particulate nitrogen in phytoplankton detritus, The maximum rate constant for the degradation of active dissolved organic phosphorus into inorganic phosphorus. To improve the concentration of active dissolved organophosphorus compounds, For inert dissolved organophosphorus concentration, The maximum rate constant for the conversion of active dissolved organophosphorus phosphorus to inert dissolved organophosphorus phosphorus. Phosphatic particulate phosphorus concentration, The maximum absorption rate constant of silicates, Nitrogen limitation factor for diatoms, The inorganic phosphorus limitation factor for diatoms, For phytoplankton particulate silicon concentration, The maximum growth rate constant of diatoms at 0℃ The maximum enzyme-controlled secretion rate constant of diatoms at 0℃ The maximum mortality rate constant of diatoms at 0℃ Diatom phosphorus limitation coefficient, Silicon confinement factor, Diatom respiration rate coefficient, The carbon-to-nitrogen ratio limiting factor for diatoms, Diatomase activity regulation coefficient, For diatom biomass, The maximum growth rate constant of dinoflagellates at 0℃ The maximum enzyme-controlled secretion rate constant of dinoflagellates at 0℃ The maximum mortality rate constant of dinoflagellates at 0℃ Nitrogen limitation coefficient for dinoflagellates Phosphorus limitation coefficient for dinoflagellates The respiration rate coefficient of dinoflagellates The carbon-to-nitrogen ratio limiting factor for dinoflagellates The regulatory coefficient of dinoflagellates enzyme activity, The regulatory coefficient of dinoflagellates enzyme activity, This refers to the biomass of dinoflagellates.

2. 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 biodiversity and decomposition processes of phytoplankton in the marine environment are linked to gene-regulated extracellular enzyme activity. The niche competition mechanism between the diatoms and dinoflagellates includes: Diatoms absorb and dissolve inorganic nitrogen, reactive phosphates and silicates 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 inert dissolved organic nitrogen; The process by which diatoms and dinoflagellates absorb, assimilate, and dissolve organic nutrients is limited by enzyme activity regulators. Specifically, the activity of nitrogen-degrading enzymes is regulated by nitrogen-limiting ascending control genes, and the activity of phosphorus-degrading enzymes is regulated by phosphorus-limiting ascending control genes. This distinguishes between diatoms and dinoflagellates.

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 debris module, whose kinetic processes include phytoplankton apoptosis, phytoplankton apoptotic cell decomposition, and microbial degradation of particulate nitrogen and phosphorus in debris.

4. 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 nutrient module is a biogeochemical module based on the bioavailability of nutrients and by introducing enzyme activity regulators. 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 are: ammonium nitrogen oxidation, nitrite nitrogen nitrification, enzyme-controlled absorption and assimilation of active dissolved organic nitrogen, enzyme-controlled secretion of active dissolved organic nitrogen, degradation of active dissolved organic nitrogen, enzyme-controlled absorption and assimilation of inert dissolved organic nitrogen, enzyme-controlled secretion of inert dissolved organic nitrogen, and degradation of inert dissolved organic nitrogen. The phosphorus migration and transformation process includes the enzymatically controlled absorption and assimilation of active soluble organophosphates, the enzymatically controlled secretion of active soluble organophosphates, the degradation of active soluble organophosphates, and the degradation of inert soluble organophosphates. The silicon migration and transformation process is a process of silicate absorption and degradation.

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 process includes the oxidation of ammonium nitrogen, the nitrification of nitrite nitrogen, the degradation of dissolved organic nitrogen, the humification of dissolved organic nitrogen, and the remineralization of detrital particulate nitrogen. 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 detrital particulate phosphorus. The silicon migration and transformation process is a process of silicate absorption and degradation 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 ammonium nitrogen is as follows: ; The nitrification process of nitrite 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 organophosphorus compounds is as follows: ; The humification process of dissolved organophosphorus compounds is as follows: ; The remineralization process of detrital particulate phosphorus is as follows: ; The process of silicate absorption and degradation of particulate silicon is as follows: 。 7. 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 life and death process includes growth, respiration, secretion, and death.

8. The method for regulating the competitive evolution mechanism of marine diatoms and dinoflagellates according to claim 7, characterized in that, The growth process of diatoms is as follows ; Diatom respiration ; The secretion process of diatoms is as follows ; The death process of diatoms is as follows .

9. 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 dinoflagellates is as follows ; The respiration process of dinoflagellates is ; The secretion process of dinoflagellates is as follows ; The death process of dinoflagellates is as follows .

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