Ecological Archives E095-014-A5

Nicole L. Goebel, Christopher A. Edwards, Michael J. Follows, Jonathan P. Zehr. 2014. Modeled diversity effects on microbial ecosystem functions of primary production, nutrient uptake, and remineralization. Ecology 95:153–163. http://dx.doi.org/10.1890/13-0421.1

Appendix E. Functional-group–productivity relationship calculations.

We tested the relationship between the number of functional groups and regionally averaged productivity for each model simulation in the baseline experiment. Averaged productivity increased monotonically with the number of functional groups, although the most productive two-functional group experiment was as productive as the most productive experiment with three functional groups (Fig. E1). Variance among functional group number ensembles decreased with increase in number of functional groups; the variance for the three-functional group ensemble was an order of magnitude lower than that for the ensemble with two functional groups. The absence of DIA was reflected in model runs with lower productivity, indicating the crucial role of DIA for optimizing modeled primary production. The combination of DIA with PLP and/or SNP functional types increased ecosystem productivity by optimizing resource use and facilitating the remineralization of high inputs of organic matter to reduced forms of nitrogen favored by small phytoplankton types.

FigE1

Fig. E1. Relationship between the number of phytoplankton functional groups and primary productivity of each model run in the baseline experiment. Productivity is spatially and temporally averaged, and vertically integrated. Legend indicates the functional groups present in each model simulation, whereby more than one phytoplankton type within each functional group may be included.


 

Table E1. (A) General characteristics and environmental preferences resulting from randomized and fixed model parameters for functional groups included in the initial model run of 78 phytoplankton types. (B) Randomly drawn parameters for the ten dominant phytoplankton types (and numbers, based on the original phytoplankton pool numbered 1 through 78) used in the baseline experiment. Values governing randomized parameters were randomly drawn from uniform and Gaussian distributions across ranges shown for Prochlorococcus-like (PLP), small non-Prochlorococcus-like (SNP), large non-diatom (LND), and diatom functional groups in (A). The parameters are applied to equations as documented in Goebel et al. (2010).

 A)

Name

Symbol

unit

PLP

SNP

LND

DIA

General Characteristics and Environmental Preferences

Low maximum growth rate, Low nutrients, Utilizes NH4 and NO2 (not NO3), High and low light

Low maximum growth rate, Low to intermediate nutrients, Utilizes all three nitrogen forms, High and low light

Intermediate maximum growth rate, High Nutrients, Utilizes all three nitrogen forms, High light

Fast maximum growth rate, High Nutrients, Utilizes all three nitrogen forms, Requires silicate, High light

Values governing randomized parameters

Phosphate half saturation constant (min, max)

KPO4

μM P

0.010, 0.015

0.015, 0.035

0.035, 0.055

0.035, 0.005

Nitrate half saturation constant (min, max)

KNO3

μM N

0.16, 0.24

0.24, 0.56

0.56, 0.88

0.56, 0.88

Nitrite half saturation constant (min, max)

KNO2

μM N

0.16, 0.24

0.24, 0.56

0.56, 0.88

0.56, 0.88

Ammonium half saturation constant (min, max)

KNH4

μM N

0.08, 0.12

0.12, 0.28

0.28, 0.44

0.28, 0.44

Silicic acid half saturation constant

Ksi

μM Si

-

-

-

1

PAR half-saturation constant (mean, standard deviation)

KPAR

(μEin m-1·s-1)-1

0.012,  0.02

0.012, 0.02

0.012, 0.006

0.012, 0.006

PAR inhibition constant (mean, standard deviation)

Kinh

(μEin m-1·s-1)-1

0.006, 1e-4

0.006, 1e-4

0.006, 5e-5

0.001, 5e-5

Temperature optimum coefficient (min, max)

To

°C

5, 25

5, 25

5, 25

5, 25

Other fixed parameters

 

Maximum growth rate

μmax

d-1

2.86

2.86

4.00

5.00

Temperature coefficient a

A

-

0.333

0.333

0.333

0.333

Temperature coefficient b

B

-

0.0010

0.0010

0.0003

0.0003

Temperature decay exponent

τ

-

4.0

4.0

4.0

4.0

Temperature decay scale

τd

°C

5.62

5.62

7.60

7.60

Temperature normalization coefficient

τn

-

0.3

0.3

0.3

0.3

Ammonium inhibition coefficient

σA

(μM N)-1

4.6

4.6

4.6

4.6

Si:P elemental ratio

rSiP

mol Si:mol P

-

-

-

16

N:P elemental ratio

rNP

mol N:mol P

16

16

16

16

C:Chl

rcchl

g C:g Chl

300

300

100

50

Phytoplankton sinking rate

w(p)

d-1

0.0

0.0

0.5

0.5

Phytplankton mortality rate

m(p)

d-1

0.1

0.1

0.1

0.1

Fraction of P mortality exported to particulates

E(p)

-

0.2

0.2

0.5

0.5

Palatability by microzooplankton

π(p)

-

1.00

1.00

0.40

0.28

Palatability by mesozooplankton

π(p)

-

0.2

0.2

1.0

0.7

Assimilation efficiency by microzoo

α(p)

-

0.5

0.5

0.2

0.2

Assimilation efficiency by macrozoo

α(p)

-

0.7

0.7

0.5

0.5

 B)

Name

PLP_05

PLP_23

PLP_77

SNP_39

SNP_31

SNP_47

DIA_69

DIA_32

DIA_46

DIA_24

Values governing randomized parameters

Phosphate half saturation constant

0.0190

0.0150

0.0410

0.0360

0.0450

0.0220

0.0230

0.0400

0.0140

0.0100

Nitrate half saturation constant

0.3010

0.2370

0.6530

0.5730

0.7220

0.3480

0.3680

0.6440

0.2260

0.1670

Nitrite half saturation constant

0.3010

0.2370

0.6530

0.5730

0.7220

0.3480

0.3680

0.6440

0.2260

0.1670

Ammonium half saturation constant

0.1505

0.1185

0.3265

0.2865

0.3610

0.1740

0.1840

0.3220

0.1130

0.0835

Silicic acid half saturation constant

-

-

-

-

-

-

1

1

1

1

PAR half-saturation constant

0.0092

0.0667

0.0184

0.0175

0.023

0.0287

0.0587

0.025

0.0404

0.0343

PAR inhibition constant

0.0059

0.0059

0.001

0.0011

0.001

0.0062

0.0058

0.0011

0.0061

0.0061

Temperature optimum coefficient

16.3

17.6

11.5

11.3

15.4

13.3

11.4

17.1

16.1

21.1

 

Literature Cited

Goebel, N. L., C. A. Edwards, J. P. Zehr, and M. J. Follows. 2010. An emergent community ecosystem model applied to the California Current System. Journal of Marine Systems 83:221–241.


[Back to E095-014]