Đang tải... (xem toàn văn)
ScanGate document
VNU JOURNAL USING OF SCIENCE, THE MARINE SEA Nat Sci, t XVII, n92 - 2001 MATHEMATICAL ECOSYSTEM AREA AND OF TAM MODELS BINH STUDY THUAN-NINH GIANG-CAU Doan TO HAI THE THUAN LAGOON Bo Faculty of Hydro Meteorology and Oceanography College of Natural Sciences, Abstract: The marine Vietnam National Unive Hanoi stem model has been established on the basis mathemat- ical simulation for the material transformation through compounds The phosphor cycle is chosen as an example for eco-hydrodynamic of the system model In the cycle, phosphorus element is transformed through five compounds (Phytoplankton, Zooplankton, Detritus, Dissolved Organic and Inorganic phosphorus) by different bio-chemical processes The eco-hydrodynamic model has been established on the basis turbulent diffuse model in combination with the material transformation model (as phosphor cycle model) The general model is analyzed into simple models, are applied to the sea area of Binh Hai lagoon of Thua Thuan-Ninh Thien-Hue province which Thuan province and Tam Giang-Cau The obtained results are very important to study the biological and ecological characteristics of marine plankton communities, to simulate and predict the variation of living and non-living compounds, especially, to monitor the marine environment and ecosystem Introduction Recently, mathematical models and numerical methods have been widely used for researching the marine ecosystems One of those is to solve the Eco-hydrodynamic prob- lems that have been established on the basis of combination between diffusion model and the model of material transformation in the marine ecosystem The results coming from the application of the model allow us to look totally and optically at the development tendency of the system under the influence of the marine thermo-hydrodynamic condi- tions The results also allow us to determine the basic and general relationship in the marine ecosystem, to predict the variation of living and non-living compounds in the sea, especially to monitor marine environment and ecosystem In this paper, some kinds of marine ecological model and Eco-hydrodynamic model are introduced The applications of these models to Binh Thuan-Ninh Thuan sea area Giang-Cau Hai lagoon in order to study characteristics and variation of com- N and Tam Doan Bo pounds of marine ecosystem, especially primary productivity and in order to study the ecological effects of physical, environmental conditions show that the good results have been obtained Equations of the models Marine Ecological Model The marine ecological model has been established on the basis of mathematical simulation for the material transformation through the compounds of the marine ecosystem, in which the living compounds are only limited by phytoplankton and zooplankton In this study, the phosphorus transformation cycle is chosen as an experiment for application of the Eco-hydrodynamic model In the cycle, the phosphorus (an essential element for life) is transformed five compounds through C{i processes bio-chemical = 5) by different K;(j = 7), fig [1] The cycles for transformation of other elements are considered in the same way Combining the cycles to each other, we have the general model for material transformation in the marine ecosystem Legend: Cy, Cy Cs — Biomass Cy Cay Phytoplankton, — Zooplankton concentration of Detritus, Organic and Inorganic respectively, Ka Ky, Ky - Own of and Dissolved Phosphorus, speeds of respiration, photosvnthesis and natural death of — Phytoplankton population, respectively Ky Ky Ks - Own speed of water filtering, death of respectively, respiration and natural Zooplankton — population, Ko, Ky ~ Own speed of decomposition Phosphorus (C4) « ~ Inorg Diss Phosphorus (C5) Fig is following: model mineralization of — organic by, b3 - Coefficient of selecting compounds, respectively bs Phytoplankton and Detritus as natural food by Zooplankton, lạ(b5) | 1: Schema of phosphorus Mathematical and by bs, be b> ~ Ratio of transformation into different material kinds bs Hae of Phosphorus in organic compounds transformation cycle in marine ecos; to simulate dynamic of material dC; /dt = Rys(i = n) transformation em in the c (1) Using where the mathematical C, is the biomass models to study (or concentration) the marine ecosystem of it? compound; variation of biomass (or concentration) of i” compound cycle, the mathematical model is following: R, - the total speed of For phosphorus transformation dC, /dt = Ry = (Ky — Ko — Ka — b K2C2)Cy dCy/dt = Re{(byCy + b3C3)b2 Kg — Ky — Ks|Cz dCy/dt ~ Ry = KyCy + KxCo + (bxCy + bgCs)(1 — bp)bg oC dC, /dt = Rg = (byCy + b3C3)(1 — b2)(1 — bg )bg K2C2 — b3 K2C2C3 — KeCa + bsbg K3Ce2 + bobs KeC3+ + brbg KoCy — KrCy dCs/dt — Rs = K7C4 + (1 = bs)bgh3C2 + (1 — bg )bg K6C3 + (1 — b7)bgKoCy — bg Ki Cy ‘The speeds of A); depends on environmental conditions, they can be - using some empirical formulae, as follows [4, 5, 6]: Ko(1/day) = PoE xp|Qo(T — 20) — Uo.Ln(MP)| WW (1/day) = Ky max-min|A, B,C, D| i Pi W2(m* /ing.day) if S=0 Kemax-5(2— $/5))/51 if 0