Neuse Estuary Eutrophication Model

Cause and Effect Relationships NeuBERN Bayes Net Estuary Model Nitrogen Inputs Cause and Effect Relationships River Flow Algal Density Chlorophyll Violations Carbon Production Sediment Oxygen Demand Harmful Algal Blooms Frequency of Hypoxia Duration of Stratification NeuBERN Bayes Net Estuary Model Number of Fishkills Fish Health Shellfish Abundance

Model proposed by Chen and Orlob (1972)

Phytoplankton (Algae) Mass Balance (equation from the model proposed by Chen and Orlob (1972)) where: V = segment volume (m3) C1 = phytoplankton concentration (g/m3) Q = flow volume (m3/t) E = diffusion coefficient (m2/t) A = segment surface/bottom area (m2) µ1 = phytoplankton growth rate (t-1) R1 = phytoplankton respiration rate (t-1) s1 = phytoplankton settling rate (t-1) M1 = phytoplankton mortality rate (t-1) µ2 = zooplankton growth rate (t-1) C2 = zooplankton concentration (g/m3) F2,1 = fractional feeding preference

(Chapra and Reckhow 1983, Chapter 14) Parameter Selection Example: Phytoplankton Settling For phytoplankton settling, another common approach is to treat phytoplankton settling as a velocity term with an areal loss: (Chapra and Reckhow 1983, Chapter 14) phytoplankton settling (mass/time) = v1AC1

Table 1. Phytoplankton settling velocities (Bowie et al. 1985)