Net primary production (NPP) = f [biomass, physiology, g (I0)]

NPP = f [chlorophyll, Zeu, Pbopt, g (I0)]

{0.02 to 30 mg m-3}

{120 m}

{0 to 30 mg C mgChl-1 h-1}

{0 to 1}

{2 to 300 mg m-2}

NPP = f [Carbon, Zeu, , g (I0)]

{5 to 100 mg m-3} {0 to 2 div. d-1}

Light scattering # particles

Common measures of scatter: particulate beam attenuation (cp)particulate backscatter coeff. (bbp)

Open—ocean particle size spectra relatively conserved

cp is:

dominated by particles in the phytoplankton size domain

sensitive to inorganic particles in the 0.5 to 20 m size range

insensitive to submicron bacteria, ‘pure water’ values are measured when 106 bacteria are present

(1) (2)

(3)

(4)

10-1

100

101

102

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

s ize [µm]

beam

atte

nuat

ion

/ pa

rticl

e vo

lum

e

Detrital-like (n=1.04+i*0.0001)

P hytoplankton-like (n=1.05+i*0.005)

10-1 101 102100

0.4

0.3

0.2

0.1

0

beam

atte

nuat

ion

/ par

ticle

vol

ume

size (um)

detrital particles

planktonic particles

14 Steps

Particle # cp per particle

cp covaries with POC

Bishop, J.K.B. 1999. Deep-Sea Res. I. 46:353-369.Bishop, J. K. B., S. E. Calvert and M. Y. S. Soon (1999) Deep-Sea Res. II 46:2699-2733.Claustre, H., A. Morel, M. Babin, C. Cailliau, D. Marie, J-C Marty, D. Tailliez and D. Vaulot (1999) J. Geophys. Res. 104:3401-3422.Gardner, W. D., I. D. Walsh and M. J. Richardson (1993) Deep-Sea Res. II. 40:171-195.Gardner, W. D., S. P. Chung, M. J. Richardson and I. D. Walsh (1995) Deep-Sea Res. II. 42:757-775.Loisel, H. and A. Morel (1998) Limnol. Oceanogr. 43: 847-858.Walsh, I. D., S. P. Chung, M. J. Richardson and W. D. Gardner (1995) Deep-Sea Res. II 42:465-477.

Therefore – cp should be a better estimate of phytoplankton carbon than POC

If true – then the ratio of cp:chlorophyll should track phytoplankton C:Chl,which is a common index of physiological variability that sharesenvironmental dependencies with Pbopt and Ek

(5)

(6)

(7)

(8)

0.1 1 10 100 1000 m

Practical POC

Particulate beam attenuation (cp)

cp:chl tracks changes in Pbopt and Ek

Behrenfeld & Boss (2004) Deep-Sea Res.50:1537-1549

(9)

0 10 20 30 40 50

0

3

6

9

12

15

18

0.0

0.3

0.6

0.9

1.2

1.5

1.8

0 10 20 30 40 50 60 70

0

3

6

9

12

15

18

0.0

0.3

0.6

0.9

1.2

1.5

1.81992 1993 1994 1995 1996 1997

* *

1994199319921991 19961995

April May June

0

2

4

6

8

0.0

0.2

0.4

0.6

0.8

1.0

653 4130 2 272523201886 312927 292625

NABE Time Series

Sequential Observation

Mea

sure

d Pb

opt

Measured c

p :Chl ratio

NABE

BATS

HOT

Mea

sure

d Pb

opt

cp :C

hl ratio

0.0 0.2 0.4 0.6 0.8 1.00

100

200

300 OliPac

cp:Chl ratioM

easu

red

E k

Ocean color inversion algorithms give us bbp , not cp

Mie calculations indicate that bbp is dominated by submicron particles, but in field populations bbp likely has a significant tail in the phytoplankton size domain.

Satellite bbp covaries with POC

Loisel, H., E. Bosc, D. Stramski, K. Oubelkheir, and P.-Y. Deschamps (2001) Geophys. Res. Lett., 28:4203-4206.Stramski, D., R. A. Reynolds, M. Kahru, and B. G. Mitchell (1999)

Science, 285:239-242.

Therefore – bbp should be a better estimate of phytoplankton carbon than POC

If true – then the ratio of chlorophyll:bbp should track phytoplankton Chl:C

and thus phytoplankton growth rates ( )

{once a correction of the background bacterial population is accounted for}

(10)

(11)

(12)

(13)

(14)

0.1 1 10 100 1000 m

Practical POC

Particulate beam attenuation (cp)

Particulate backscatter (bbp)

0 5 10 15 20 25 300.01

0.04

0.07

0.10

0.13

0.16

0.19

0 1 2 3

0.005

0.020

0.035

0.050

0.065

0.080

0.20.40.60.81.00.001

0.006

0.011

0.016

Chl

:C (m

g m

g-1 )

Light (moles m-2 h-1)

Temperature (oC)

Chl

:Cm

ax

Growth rate (div. d-1)

Chl

:Cm

in

Low Nutrient stress High

3 primary factors

Light

Temperature

Nutrients

Chl:C physiologyLa

bora

tory

Chl:Cmax

Chl:Cmin

Dunaliella tertiolecta20 oCReplete nutrientsExponential growth phase

Geider (1987) New Phytol. 106: 1-34

16 species = Diatoms

= all other species

Laws & Bannister (1980) Limnol. Oceanogr. 25: 457-473

Thalassiosira fluviatilis = NO3 limited cultures

= NH4 limited cultures

= PO4 limited cultures

0.0 0.2 0.4 0.6 0.80.000

0.001

0.002

0.003

0.004

0.005

75o

0o

15o

30o

90o

60o 45o

60o

75o90o

15o

30o

45o

75o

0o

15o

30o

90o

60o 45o

60o

75o90o

15o

30o

45o NP

SP SA

NANP

SP

CP

SA

NA

SI

NI CA

SO

L0L1L2L3L4

SO-all

Chlorophyll

Variance L

evel

excluded

28 Regional Bins

b bp (

m-1

)

Chlorophyll (mg m-3)

‘physiology domain’

‘biomass domain’

Intercept = bbp from stable component of the bacterial population

C = scalar (bbp – intercept) = 13,000 (bbp – 0.00035)

Intercept = 0.00017 m-1 Stramski & Kiefer (1991) Prog. Oceanogr. 28, 343-383 Cho & Azam (1990) Mar. Ecol. Prog. Ser., 63, 253-259

Phytoplankton Carbon = 25 – 35% POC Eppley et al. (1992) J. Geophys. Res., 97, 655-661 DuRand et al. (2001) Deep-Sea Res. II, 48, 1983-2003 Gundersen et al. (2001) Deep-Sea Res. II 48, 1697-1718

0

0.1

0.2

0.3

0.4

0.5

0.6

0 0.2 0.4 0.6 0.8

0.0 0.2 0.4 0.6 0.80.000

0.001

0.002

0.003

0.004

0.005b b

p (m

-1)

Satellite bbp vs field cp

Same bilinear pattern

Anticipated intercept bbp > 0 cp = 0

Ratio of slopes = 0.0008

{phytoplankton = 0.0005 – 0.0009}c p (m

-1)

Chlorophyll (mg m-3)

South Atlantic

0 5 10 15 20 25 300.01

0.04

0.07

0.10

0.13

0.16

0.19

0 5 10 15 20 25 300.01

0.02

0.03

0.04

0.05

0 1 2 3

0.005

0.020

0.035

0.050

0.065

0.080

0 1 2 3

0.005

0.007

0.009

0.011

0.013

0 5 10 15 20 25 300.001

0.006

0.011

0.016

0.20.40.60.81.00.001

0.006

0.011

0.016

Chl

:C (m

g m

g-1 )

Light (moles photons m-2 h-1)

Temperature (oC)

Chl

:Cm

ax

Growth rate (div. d-1)

Chl

:Cm

in

Low Nutrient stress High

Labo

rato

ry

Temperature (oC)

Low Nutrient stress High

Chl:C

(mg m

g-1)

Chl:C

max

Chl:C

min

Space

{median r2 = 0.85}

75o

0o

15o

30o

60o 45o

60o

75o90o

15o

30o 45o

75o

0o

15o

30o

60o 45o

60o

75o90o

15o

30o 45o NP

SP SA

NANP

SP

CP

SA

NA

SI

NI CA

SO90o90o

0.02

0.03

0.04

0.05

0.06

0.003

0.005

0.007

0.08

0.10

0.12

0.14

0.007

0.010

0.013

0.016

0.04

0.07

0.10

0.13

0.005

0.008

0.011

0.014

0.0

0.1

0.2

0.3

0.4

0.01

0.02

0.03

1998 1999 2000 2001 2002

0.10

0.15

0.20

0.25

0.30

0.008

0.012

0.016

0.020

Year

Phyt

opla

nkto

n C

hlor

ophy

ll (

) a

nd sc

aled

Car

bon

(

)

Satellite Chl:C

Ratio ( )

The 5 basic patterns

Growth rate ( ) = max f (nuts, temp) g (light)

2 divisions d-1

Banse (1991)

Chl:Csat

( Chl:CN,T-max ) Light

range = 0 to 1 range = 0 to 1

0 1 2 30.00

0.01

0.02

0.03

0.04

0.05

Light (moles photons m-2 h-1)

Chl

:C (m

g m

g-1 )

1 – exp -3light

0 0.5 1.0 1.5 2.0

Growth rate (division d-1)

Boreal Summer

Boreal Winter

Growth rate (divisions d-1)0.0 0.5 1.0 1.5 2.0

Rel

ativ

e Fr

eque

ncy

0.0

0.2

0.4

0.6

0.8

1.0

Rel

ativ

e fr

eque

ncy

Bor

eal W

inte

r

Chlorophyll basedCarbon based

Bor

eal S

umm

er

Net Primary Production (mg m-2)0 1200800400 1500

Backup Slides

0 5 10 15 20 250

5

10

15

20

25

0

5

10

15

20

25

0 5 10 15 20 25

Balch et al. 1992 Antoine et al. 1996

Megard 1972 Behrenfeld & Falkowski 1997

Net primary production (NPP) = f [biomass, physiology, g (I0)]

NPP = f [chlorophyll, Zeu, Pbopt, g (I0)]

{0.02 to 30 mg m-3}

{120 m}

{0 to 30 mg C mgChl-1 h-1}

{0 to 1}

{2 to 300 mg m-2}

NPP = f [Carbon, Zeu, , g (I0)]

{5 to 100 mg m-3} {0 to 2 div. d-1}

Measured Pbopt

Mod

eled

Pb o

pt40% 40-50%

Model #1

Model #4Model #3

Model #2

Growth Irradiance0 1 2 3

Phot

osyn

thes

is

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Ligh

t-sat

urat

ed P

hoto

synt

hesi

s (P

* max

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.01 0.03 0.05 0.070.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Light-limited Photosynthesis (Nmax)0.01 0.03 0.05 0.07 0.01 0.03 0.05 0.07

Ek = 146r2 = 0.63

n = 17o.d. = 0.2 - 0.5

Ek = 138r2 = 0.73

n = 14o.d. = 0.7 - 1.0

Ek = 118r2 = 0.95

n = 16o.d. = 1.4 - 1.9

Ek = 95r2 = 0.91

n = 16o.d. = 2.1 - 2.6

Ek = 59r2 = 0.79

n = 20o.d. = 2.7 - 3.3

Ek = 42r2 = 0.80

n = 19o.d. = 3.6 - 4.3

Ek = 27r2 = 0.75n = 17o.d. = 4.5 - 5.0

Ek = 21r2 = 0.50n = 14o.d. = 5.3 - 5.8

Ek = 12r2 = 0.77n = 25o.d. = 6.2 - 10.6

Optical Depth0 1 2 3 4 5 6 7

E k

0

40

80

120

160

Observed

Calculated

CBA

D

IHG

FE

J K

Sequential hours of Experiment0 20 40 60 80

Car

bon

Fixa

tion

& Ac

cum

ulat

ion

Rat

e

-6

-4

-2

0

2

4

6

Time of Day0 4 8 12 16 20 24

FLS

0.10

0.12

0.14

0.16

0.18

0.20

N:C

0.15

0.17

0.19

0.21

Time of Day0 4 8 12 16 20

rbcL

0

5

10

15

Sequential hours of Experiment0 20 40 60 80

Pbm

ax

0

2

4

6

8

10

12

"b

0.00

0.01

0.02

0.03A

D

CB