Organic Matter Metabolism in a Coastal Ocean Ecosystem

Patricia MatraiMike SierackiNicole Poulton

Carlton Rauschenberg

Bigelow Laboratoryfor Ocean Sciences

W. Boothbay HarborMaine

NASA OCRT 4/11-13/06 Newport, RI

In Collaboration with: University of New Hampshire

Center for Coastal Ocean Observation and Analysis

Janet CampbellJoe Salisbury

Talk outline

•Project objectives

•Study site and measurements

•Some first year results

•Respiration models

•Preliminary remote sensing results

•Conclusions

Project Objectives•Primary Objectives:

•Can microbial respiration be modeled by temperature, chlorophyll, primary production, and DOM?

•If so, how well can surface water respiration be estimated by satellite remote sensing?

•Secondary Objectives:•What is the balance of planktonic microbial respiration to primary production in a river plume system?

•How does planktonic food web structure relate to the system metabolic balance?

Gulf of Maine Primary Study Area

(GoMOOS C)

(GoMOOS B)

Study Methods• Monthly cruises from Kennebec River (Bath,

Maine) to Portsmouth, NH• 5 Stations, surface samples• Respiration (24h O2 incubations)• Primary production (12h 14C incubations)• Microplankton and particle analysis

• FlowCAM, flow cytometry, microscopy• Size spectra, 0.2 - >200 µm

• Chlorophyll, T, S, TOC, POC, ∆13C, nutrients

• Bacterial single-cell respiration (CTC)

Temperature and Salinity

0

5

10

15

20

25

Feb-05 Mar-05 May-05 Jun-05 Jul-05 Sep-05 Oct-05 Dec-05

Tem

pera

ture

°C

Stn1

Stn2

Stn3

Stn4

Stn5

Temperature pattern similar at all stations

River and plume stations show spring and fall runoff peaks (low salinity)

0

5

10

15

20

25

30

35

Feb- 05 Mar- 05 May- 05 J un- 05 J ul- 05 Sep- 05 Oct- 05 Dec- 05

Salin

ity p

su

Stn1

Stn2

Stn3

Stn4

Stn5

Bacteria and <20µm Phytoplankton Abundances

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

Feb-05 Mar-05 May-05 J un-05 J ul-05 Sep-05 Oct-05 Dec-05

Tota

l Euks (

mL-1

)

Stn1Stn2Stn3Stn4Stn5

0

50000

100000

150000

200000

250000

Feb-05 Mar-05 May-05 J un-05 J ul-05 Sep-05 Oct-05 Dec-05

Synechococcus (

mL-1

)

Stn1Stn2Stn3Stn4Stn5

0

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

Feb-05 Mar-05 May-05 J un-05 J ul-05 Sep-05 Oct-05 Dec-05

Bacte

ria (

mL-1

)

Stn1Stn2Stn3Stn4Stn5

Eukaryotes

Synechococcus

HeterotrophicBacteria

Microphytoplankton Abundance(15 - 200 µm, FlowCAM)

Apr Jun Oct Dec

0

1

2

3

4

5

6

7

Feb-05 Mar-05 May-05 Jun-05 Jul-05 Sep-05 Oct-05 Dec-05

Chl

orop

hyll

ug/L

Stn1Stn2Stn3Stn4Stn5

0

100

200

300

400

500

600

700

800

Feb-05 Mar-05 May-05 Jun-05 Jul-05 Sep-05 Oct-05 Dec-05

Prim

ary

Prod

uctio

n ug

C/L

/d

Stn1Stn2Stn3Stn4Stn5

Chl

1° Prod

0

20

40

60

80

100

120

140

160

Feb-05 Mar-05 May-05 Jun-05 Jul-05 Sep-05 Oct-05 Dec-05

Mic

robi

al R

espi

ratio

n Ra

te m

l O2

/L /

d

Stn1

Stn2

Stn3

Stn4

Stn5

Seasonal Trends in Chlorophyll, Primary Production, and Respiration

Resp

Chl

1° Prod

Resp

Seasonal Trends in POC, Nutrients, and δ 13C/12C

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Feb-05 Mar-05 May-05 Jun-05 Jul-05 Sep-05 Oct-05 Dec-05

PO

C u

g/

L

Stn1

Stn2

Stn3

Stn4

Stn5

POC

-32.0

-30.0

-28.0

-26.0

-24.0

-22.0

-20.0

Feb-05 Mar-05 May-05 Jun-05 Jul-05 Sep-05 Oct-05 Dec-05

δ1

3/C

12C

Stn1

Stn2

Stn3

Stn4

Stn5

δ 13C/12C

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Feb-05 Mar-05 May-05 J un-05 J ul-05 Sep-05 Oct-05 Dec-05

PO4u

M

Stn1

Stn2

Stn3

Stn4

Stn5

PO4

0

1

2

3

4

5

6

7

8

9

10

Feb-05 Mar-05 May-05 Jun-05 Jul-05 Sep-05 Oct-05 Dec-05

NO

3 +

NO

2

uM

Stn1

Stn2

Stn3

Stn4

Stn5

NO3 + NO2

Annual Station Means

Downstream:Chlorophyll declines

1° Production declines

Respiration increases

0

1

2

3

1 2 3 4 5

Station

Mean C

hlo

rophyll

(µg/L

)

050

100150200250

1 2 3 4 5

Station

Prim

ary

Pro

duct

ion

(µgC

/L/d

)

0

2

4

6

8

1 2 3 4 5

Station

Mean R

esp

irati

on

rate

(µM

O2/d

)

River Coast

Chl

Resp

PP

Surface respiration vs. primary production (µgC L-1

d-1)Primary production vs. respiration

-20

0

20

40

60

80

100

120

140

160

0 200 400 600 800

Primary production (µgC/L/d)

Resp

irati

on (

µgC

/L/d

)

1:1

Overall system mean:R is 30% of P

Surface respiration vs. primary production (µgC L-1

d-1)Primary production vs. respiration

-20

0

20

40

60

80

100

120

140

160

0 200 400 600 800

Primary production (µgC/L/d)

Resp

irati

on (

µgC

/L/d

)

River + plumeAug, Sept

Spring bloomMay, June

1:1

Ecosystem relationships

Cole et al. 1988, White et al. 1991, del Giorgio et al. 1997

Rivkin & Legendre 2001

Method #1 BA = f(Chl)

BR = f(BA, T)

Method #2 BP = f(BA, T)

BR = f(BP, T)

Method #3 BR = f(NPP)

Example Gulf of Maine Respiration Images13 May 2005

SST CHL

BR1 (BA) BR2 (BP)

Conclusions

• Kennebec River plume/Gulf of Maine system is dynamic, biologically rich, and productive

Primary production exceeds respiration most of the year, R was 30% of P for the whole system over 1 year.

Preliminary estimates of respiration from remote sensing data using ecosystem relationships are within an order of magnitude of in-water measurements, but further analysis and validation are needed.

And Thanks to:

Kay Kilpatrick, RSMAS, U. Miami

Ben Tupper, Bigelow LaboratoryPaul Pelletier, Capt. R/V Gulf ChallengerChris Hunt, Mike Novak, UNH Coastal Transect crew

Carbon Cycle Science