Feb 23, 2014
STELLA 10.0.3Table 3 Species parameters used in the model simulations
Parameter Description Microcystis Diatoms Green algae Units
mmax(Topt) Maximum specific growth rate at optimum
temperature
0.80(1) 1.00*(2) 0.63* day1
a Initial slope of light-dependent growth 0.01* 0.035* 0.035* day1
(mmolm2 s1)1
Topt Optimum temperature 28.2(1) 20.0(2) 17.0* 1C
b Coefficient in optimum curve 5.77(1) 4.68(2) 18.61* –
R1 Coefficient in optimum curve 1.30(1) 1.02(2) 1.02* –
R2 Coefficient in optimum curve 1.37(1) 1.15(2) 1.04* –
m(20) Specific loss rate at 20 1C 0.08(3) 0.08* 0.06* day1
Q Temperature dependence of specific loss rate 2.16(3) 1.63(3) 1.63* –
k Specific light attenuation coefficient 3.4(4) 70(4) 70* mm2 cell1
v Sinking or flotation velocity 0.500(4) 0.06* 0.04* mh1
N(0) Initial population density 5108* 0.5108* 0.5108* cellsm3
dissolved N is treated as a global variable that is mixed throughout the water column and depleted by growth, and increased by the loss of APFA
the slices are 20 cm dep with the center being at 10, 30, 50, 70 and 90
environmental data are generated separately and imported from a table "met-data-1"
incident light (already corrected for reflection)
slice temperature
inter-slice mixing rate - expressed as from shallow to deeper as positive
cell count is in terms of nitrogen per liter
KAFPA is around 5 um2 cell^-1 and to convert that to nitrogen per cell
assume that a million cells per liter = 1000 u mol N /liter in the cells
(5 x 10^-6 m^2 /cell )*1000 cells/umol N = .005 m^2/umolN
growth rates in hours .8 d^-1 = .033 hr^-1
added sin curve to light
if sin((time-6)*PI/12 >0 then 2000*sin((time-6)*PI/12) else 0
dawn is 6 am, noon is max light
constant light vs sin light check
constant 100 --> APFA decline Diatom10 up to about 200
constant 500 --> slower loss of APFA
constant 1000 --> initial increase in APFA
constant 1500 --> all levels of APFA do well for first 5 days
sin max = 2000: diatoms10 to 250, APFA slight decline
sin max = 2500, 1500, 1000: no difference in pattern
change mixing profile from .04, 0.3, 0.1, 0.1
mix profile 0.05, 0.04, 0.03, 0.02 - no difference
mix profile 0.04 all the way down
nighttime loss seems to be the biggest issue
reduce temperature of surface
lowering extinction coefficiencts allows APFA to grow and dominate (APFA to .001 and diatoms to .01)
something very bizzare going on with diatoms 90 - gets a super spike for no reason
changing the k1/2 from 10 to 20 moderated, but didn't eliminate it