non-conservative doc transformations in maine watersheds ... · 5/9/07 balch et al. nasa ocrt,...

5/9/07 Balch et al. NASA OCRT, Seattle 1

Non-conservative DOCtransformations in Maine watersheds:

“Can you tell the tea by its color?”

W. Balch (Bigelow Lab)C. Roesler (Bigelow Lab)

T. Huntington (USGS Augusta)G. Aiken (USGS Boulder)H. Xue (University Maine)

A. Barnard (Wet Labs)


Range of DOC for Surface Waters (“Tea Quantity”)

6 12 18 24

Everglades, FLSuwannee R

Group 1

Group 2

Group 3

Group 4

Group 2Piscataquis

SebecPleasant

(Ave DOC 6.5)

Group 3No BranchSo Branch

West BranchEast Branch(Ave DOC 8)

Group 1Kennebec

Androscoggin(Ave DOC 7)

Group 4MattawamkeagPassadumkeag

Sunkhaze(Ave DOC 15)

30

Mississippi


Range of SUVA [spec.UV a254] = aromaticity (“Tea flavor”)

1.0 2.0 3.0 4.0

Lake Fryxell, AntWilliams Lk, MN

Flathead R., MT

Santa Ana R., CARio Grande, TXSleepers R., VT

Calcasieu R., LABogue Falaya, LA

Cutoff Slough, CABayou Teche, LA

Everglades, FLSnake R., WA

Shingobee Inlet, MN

Group 1

Group 2

Group 3

Group 4

Group 2Piscataquis

SebecPleasant

(Ave DOC 6.5)

Group 3No BranchSo Branch

West BranchEast Branch(Ave DOC 8)

Group 1Kennebec

Androscoggin(Ave DOC 7)

Group 4MattawamkeagPassadumkeag

Sunkhaze(Ave DOC 15)

Mississippi

Atchafalaya

Colorado

ColumbiaYukon

Aromaticity

Bay & Gulf sampling:Ships, buoys, AUV’s

-Modeling

-Analytical organic chemistry

The “glue” that holds itall together:

-Optical proxies for carbon

Assets used in this study

Upper water shed/riversampling for flow, opticalproxies, chemical analyses

Remote sensing


DOC export from the Penobscot River and Selected Tributaries

2004 through 2005

1000

10000

100000

1000000

10000000

1/1/04 4/1/04 7/1/04 9/30/04 12/31/04 4/1/05 7/1/05 9/30/05 12/31/05

DO

C E

xp

ort

(kg

/day)

Penobscot 7764 sq mi Mattawamkeag 1508 sq mi

East Branch 1118 sq mi West Branch 2115 sq mi


Bogs…DOCrich

Forested/Lumbered


FrankfortFlats

POC changes through river…


y = 1.0492x - 0.2488

R2 = 0.9942

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0 2 4 6 8 10 12

Aiken DOC

Ch

ris

' D

OC

How do our DOC techniques compare to others?

1:1 line

DO

C (m

g L-1

; “m

arin

e ap

proa

ch”)

Osb

orn,

NR

L, W

ash.

D.C

.

DOC (mg L-1; “FW approach”)Aiken, USGS, Boulder, Co


Riveroutfall

BayWMCC

ExtEMCC

Gulf of Maine

Gradual decline

Through the Bay

DO

C (m

g L-1

)How much does DOC quantity change

from Penobscot Bay to the Gulf of Maine?


Flowpath SUVA 10/05

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Edd

ingt

on

Pen

Bay

1

Pen

Bay

2

Pen

Bay

3

Pen

Bay

4

Pen

Bay

5

Pen

Bay

6

Pen

Bay

7

Pen

Bay

8

Gulf -

69.

37

Gulf -

69.

17

Gulf -

GoM

oos

Gulf -

68.

51

Gulf -

68.

28

Gulf -

68.

13

Gulf -

67.

57

Gulf -

67.

38

Gulf -

67.

24

Gulf -

67.

10

Gulf -

66.

43

Gulf -

66.

21

SU

VA 10/14

10/4

Riveroutfall

BayWMCC

ExtEMCC

Gulf of Maine

SUV

A(1

0-3 m

2 mgD

OC

-1; 2

54nm

)

How does the aromaticity of the DOC (“flavor”)change from Bay to Gulf?

BIG TRANSFORMATION AT BAY EXIT TO GOM

{Sargasso


Salinity vs DOC and SUVA

(Oct 2006)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00

Salinity (ppt)

DO

C (

mg

C/L

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0Bay DOC

Gulf DOC

Bay SUVA

Gulf SUVA

Salinity (PSU)

DO

C (m

g C

L-1

)

SUV

A (1

0-3 m

2 mg

DO

C-1

; 254

nm)


DOC

DOM

aCDOM

FCDOM

Dissolved Organic Carbon Proxies


0

0.1

0.2

0.3

0.4

0.5

0.0 5.0 10.0 15.0

DOC

Abs

0

0.02

0.04

0.06

0.08

0.1

254nm

370nm

412nm

Penobscot Bay Transect 10-2006

DOC (mgC L-1)Abs

orba

nce

(254

nm, 3

70nm

)

0

0.1

0.2

0.3

0.4

0.5

0.0 5.0 10.0 15.0

DOC

Abs

0

0.02

0.04

0.06

0.08

0.1

254nm

370nm

412nm

Absorbance (412nm

)


Latit

ude

(deg

)

Fluo

resc

ent c

DO

M (p

pb Q

SE)

Salinity (PSU)

Non-linear cDOM fluorescence vssalinity…


But normalize that cDOM fluorescence tothe maximum observed at any one time…

Salinity (PSU)Fluo

r. cD

OM

/max

cD

OM Frankfort Flats

Latit

ude

(deg

)


Now normalize cDOM to discharge…“How well is the tea steeped?”

Latit

ude

(deg

)

cDO

M /

disc

harg

e (p

pb Q

SE/C

FS)

May

Aug

Jul, Sep, Oct

Salinity (PSU)

spring

fall


δ13C behaves nonconservatively with respectsalinity and DOC concentration

δ13 C

Salinity (PSU)… at ~20-22PSU, there is a transformation

Marine(heavy)

Terrest.(light)

…and a strong transformationbetween buoy F and theGulf…but where?


MF

Y

New transects

Original Line


It is clear that inthe Gulf of

Maine,transformationsare occurring,

too, in [CDOM]and color

Combined GOM cDOM dataa g

412

(m-1

)S g

(nm

-1)

Salinity (PSU)

Marine

Terr.

Nine years of agp412 …2004 through 2006 wereextraordinary years for land-sea C transport

’06‘05‘04‘03‘02‘01’00’99‘98

Portland, ME Yarmouth, NS

#1 WetDry

Usuallysawelevatedvalues inSS watercomingfrom Gulfof StLawrence

Clear influence of Maine rivers

Since 2004, little elevatedSS CDOM observed!

m-1

Dry

#2 Wet

Unprecedented input ofCDOM from Maine rivers


DOC MODELOct to Dec

2004-Dry year

Mg DOC L-1

2005-Wettest year on record

Mg DOC L-1


0.7799

How long does it take for DOC to makeit down to the Gulf of Maine (buoy F)?


‘05

‘04

Mod

elSh

ip O

bsHow doesmodeled andmeasuredDOC comparealong theGoM betweenYarmouth andPortland?

P<0.001

DOC export

XX

XX


Organic CarbonTime Series

• Discharge– Spring freshet

• Ice melt• precipitation

– Autumn rains• Algal Organic Carbon

– (0.5 million kg)• Non-algal Particulate

organic Carbon– (3 million kg)

• Dissolved OrganicCarbon– (40 million kg)

Carbon Export = 43.5 million kg

phyto C: non-phyto C: DOC

1:6:80

2005


DOC (and tea steeping)• You can tell “tea” quantity by its color in these Maine watersheds• Tea color tells less about composition due to nonconservative

changes (e.g. can’t tell if it is a “malty mix with essence of maplebark” vs. a “smokey mix of pine needles and sod)”.

• Beware how long you let your tea steep…seasonal changes instrength.

• Major chemical transforms occurring at 20-22 and 31 PSU.SUCH CHANGES CAN BE MODELED.

• Extremes in precipitation associated with major bio-optical shiftsin GoM as carbon moves from land to sea. DOC export fromsingle watershed is 40% of all GOM primary production.Balance in heterotrophic vs autotrophic production?

• Future: time-series sampling, focus on carbon transformations,with improvements in modeling and optical proxies, use remotesensing to study patterns of C export and GOM production.


THANK YOU!

non-conservative doc transformations in maine watersheds ... · 5/9/07 balch et al. nasa ocrt,...

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