Riparian zone control on doc kevin bishop

2013‐11‐10

1

Department of Aquatic Science and Assessment

Riparian zone control on DOC in boreal streams: ”Does this amplify the climate response?”

Photo: Erkki Oksanen, Met

Kevin Bishop, Thomas Grabs, Hjalmar Laudon, Jan Seibert

Dissolved Organic Carbon (DOC)Natural Organic Matter

– A nasty beast

Photo: Stefan Löfgren

2013‐11‐10

2

DOC in

Fenno‐Scandian

Surface Water

There is lots –defines

aquatic life,

impactsdrinking water

10

1

0.1DO

C (

mg

L-1)

DOC is increasing!

• 50%‐100% increase 1990‐2005

Monteith, et al. 2007 NatureHyttebörn et al. in prep

2013‐11‐10

3

C. Freeman, et. al. Nature (2001)

• Temperature first explanation

• Other Suggestions:Acidification RecoveryRainfall, Ionic strength, N‐dep, CO2

Still looking for mechanism(s)…

-2

-1

0

1

2

3

198

8

198

9

199

0

199

1

199

2

199

3

199

4

199

5

199

6

199

7

199

8

199

9

200

0

Sta

nd

ard

ise

d D

OC

co

nc

en

tra

tio

n

Why is DOC is Rising?

Lakes

Streams

Year

1970 1980 1990 2000

CO

D (

KM

nO4

[mg/

l])

20

25

30

35

40

45

50

55

60

Future Climate: 25% increase in runoff6% higher DOC

Flow and Sulfate Predict DOC in 28 Swedish Rivers 1970-2005

Erlandsson et al., Global Change Biology (2007)

2013‐11‐10

4

Year

1970 1980 1990 2000

CO

D (

KM

nO4

[mg/

l])

20

25

30

35

40

45

50

55

60

Future Climate: 25% increase in runoff6% higher DOC Erlandsson et al.,

Global Change Biology (2007)


2013‐11‐10

5

Shallow Groundwater has low DOC (< 2 mg/L), Streams are 10, 20, 30 mg/L

Runoff DOC comes from ”Connected” Organic Soils in the Near‐Stream/Rpiarian Zone and Wetlands


Painting the boreal waterscape brown

Origins of DOC in the Riparian Zone

2013‐11‐10

6

Oxic conditions

Biological Activity

µ-bial Decomposition

Anoxic conditions

Biological Activity

µ-bial Decomposition

Respired CO2

Fixed

CO2Respired CO2

Fixed

CO2

Hillslope/Upland,

Various Soils (often podsols in SE)

Depth to Gw-Table

Riparian Zone,

Hydromorphic Soils

Respired CO2

Fixed

CO2Respired CO2

Fixed

CO2

C

CCC

Carbon storage

Carbon storage

Hillslope/Upland,

Various Soils (often podsols in SE)

Riparian Zone,

Hydromorphic Soils

2013‐11‐10

7

C

C

C

C

C

C

C

C

C-TransportGW-Flow

Hillslope/Upland,

(More) Vertical drainage

Riparian Zone,

Lateral drainage

C

C

C

C

C

C

C-TransportGW-Flow

C

C

C

C

C

C

short term

Hillslope/Upland,

(More) Vertical drainage

Riparian Zone,

Lateral drainage

longterm

2013‐11‐10

8

Riparian Concentration Integration Model (RIM)

0 20 40 60 80

TOC [mg/L]

1

0.8

0.6

0.4

0.2

0

De

pth

be

low

sur

face

[m]

0

0.2

0.4

0.6

0.8

1

Gro

und

wat

er le

vel [

m b

elo

w s

urfa

ce] 0 2 4 6 8 10

Runoff [mm/d]

Seibert et al. 2009 (Hess)

Load

dz c(z)q(z)

2013‐11‐10

9

Chemostat – whatever passes gets the same ”color” -- Instantaneous, no storages involved- Vertically differentiated

Riparian Chemostat

Static

Landscape/Catchment Water≠ Runoff Chemistry

The Riparian Zone is:1. A Solution2. A Panacea3. The Ultimate Black Box4. One zone to Rule them all…

2013‐11‐10

10

Riparianobservatory

13 Sites

5 Depths/ Site

2 Lysimeters/ Depth

1 Gw-Well/ Site

9 Sampling Campaigns

TOC*, pH, absorbance, anions, cations, O18

+ lots of help!

15

45

75

30

60

Krycklan Riparian ObservatoryTesting the Riparian Hypothesis/Dream

wet

moraine

fluvial

sediment

dry

moraine

Riparian Soils: Temporal Variations(with soil temperature)

2013‐11‐10

11

Riparian Chemostat

Varying with: Depth Season

Seasonally Variable Chemostat [sic]

Temperature Sensitivity of DOC profile – captures seasonality, improves fit!

2013‐11‐10

12

Modeling a decade of DOC Dynamics

Aneboda –Southern Sweden

Gammtratten –Northern Sweden


Why does the Riparian Zone Amplify Climate Change effects on DOC?

• Warmer

• More rain

• Less snow

• More runoff all year

2013‐11‐10

13

Seasonal Chemostat and Climate Change‐ less snowmelt, more autumn flow‐more flows when soils warm


Statistical Regression a

RiparianModel b

Mean TOC Increase ~1 mg/L (6%) ~4 mg/L (25%)

Autumn peak difference … ~10 mg/L

IPCC Hadley A Scenario, 1.5 C temperature increase, 25% more runoff (HBV modeling).

TOC increases in a future climate

aErlandsson et al., 2008 Global Change Biology ; bWinterdahl et al., 2011, Water Resources Research.

2013‐11‐10

14

Year

1970 1980 1990 2000

CO

D (

KM

nO4

[mg/

l])

20

25

30

35

40

45

50

55

60

Future Climate: 25% increase in runoff6% higher DOC


Erlandsson et al., Global Change Biology (2007)


Warmer, wetter climate amplifies DOC export from the Riparian Zone:

Shift flow from Spring flood (cold soil)to rain events through warmer soils

2013‐11‐10

15

Thanks for your time!

…and all these years to dig into the RZ with friends and colleagues.

©Bill Waterson

Technology

Riparian zone control on doc kevin bishop