NutrientLimited Algae Growth: Intracellular v's' Extracellular Kinetics

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Topic

• Nutrient-Limited Algae Growth Intracellular v.s.
  Extracellular Kinetics
• BY Li, Lanhai

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Process of Algae Growth
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Problem

• Nutrients ? Algae growth
• External nutrient limitation
• Internal nutrient limitation

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Objective

• To compare algae dynamic behavior through two
  different nutrient-limitation methods

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Assumptions

• Totally mixing within aquatic system
• Same uptake rate of inorganic nutrients under
  internal and external limitations.

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Components of the Model

• External inorganic nutrients (IN,IP)
• Internal nutrients (PN,PP)
• Phytoplankton biomass (PC)
• Zooplankton (ZC, ZN, ZP)
• Detritus (DC,DN,DP)
• Exogenous factors (Temperature, Light)

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Mathematical FormulationPhytoplankton Biomass
(PC) dPC/dt Production - PC Loss PRPC -
(GRPC REPC SEPC DEPC)
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• Rate equations
• PRPC µF(I)F1(T)F1(N,P)PC
• GRPC µz F2(T)(1/F(PC))ZC
• REPC µr PC
• SEPC µs F2(N,P) PC
• DEPC µd F2(N,P) PC
• µ are the coefficient. F2(T), F(PC) and F2(N,P)
  are temperature, nutrient and algae dependence
  functions for grazing.

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Production (PRPC)

• PRPC µF(I)F1(T)F1(N,P)PC
• Light function (F(I))
• I/IK IltIK
• F(I)
• 1 IgtIK
• Temperature Function (F1(T))
• F1(T) ?g(T-20)
• Where
• µ Max. growth coefficient at 20C I Actual
  irradiation
• IK light saturation T Temperature ?g Temp
  coefficient

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• Internal Nutrient dependence function F1(N,P)
• Where PPmin, PPmax, PPmin, Ppmax are Min. and
  Max. internal N and P content, respectively.
• KC Half saturation constant for phosphorus in
  phytoplankton

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• External Nutrient dependence function F1(N,P)
• hn, hp are half N and P saturation constant

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Inorganic nutrient concentration
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Internal nutrients

• dPN/dt (PRPC - REPC - GRPC - SEPC - DEPC)
  (PN/PC)
• dPP/dt (PRPC - REPC - GRPC - SEPC - DEPC)
  (PP/PC)

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• Zooplankton
• dZC/dt PRZC - REZC - DEZC
• dZN/dt (PRZC - REZC - DEZC) (ZN/ZC)
• dZP/dt (PRZC - REZC - DEZC) ZP/ZC

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• Detritus
• dDC/dt GEDC - SEDC - MIDC
• dDN/dt GEDN - SEDN - MIDN
• dDP/dt GEDP - SEDP - MIDP

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Inorganic nutrients

• dIN/dt MIIN - UPPN
• UPPN min(VKNINPC, PRPCPNmax)
• MIIN REPN MIDN REZN RESN
• RESN KSN F5(T) (SEDN SEPN)
• (Mineralization of Sediment)
• dIP/dt MIIP - UPPP
• UPPP min(VKPIPPC, PRPCPPmax)

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Model and Behavior

• Details of the model using VisSim

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Limitation expression
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Uptake rate of IN IP
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Lets go to VisSim
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Discussion and Conclusion

• Parameter calibration
• Difference in Quantity.

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Further work

• To compare models behavior with field results.
• Quantitative evaluation using statistics

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• END