Patterns of nutrient distributions in the Patterns of nutrient distributions in the St. Croix and Upper Mississippi Rivers: St. Croix and Upper Mississippi Rivers:

Preliminary evaluation of variation among Preliminary evaluation of variation among channels, flowing backwaters and isolated channels, flowing backwaters and isolated

backwatersbackwaters

William RichardsonWilliam Richardson11, Lynn Bartsch, Lynn Bartsch11, Michelle Bartsch, Michelle Bartsch11, Richard , Richard KieslingKiesling22, Brenda Moroska, Brenda Moroska--LaFrancoisLaFrancois33, Kathy Lee, Kathy Lee22

11 USGS Upper Midwest Environmental Sciences Center, La Crosse, WiUSGS Upper Midwest Environmental Sciences Center, La Crosse, Wisconsinsconsin22 USGS Minnesota Water Science Center, USGS Minnesota Water Science Center, MoundsviewMoundsview, Minnesota, Minnesota33 National Park Service, Midwest Region, St. Croix Watershed ReseNational Park Service, Midwest Region, St. Croix Watershed Research arch

Station, MinnesotaStation, Minnesota

Flood plain river characteristics of interest:

Main Channels• high water column (wc) nutrient concentrations• short hydraulic retention time• low sediment carbon concentrations• high sediment oxygen concentrations

Flowing backwaters (side channels)• intermediate wc nutrient concentrations• intermediate hydraulic retention times• intermediate sediment carbon• variable sediment oxygen concentrations

Isolated backwaters• potentially depleted wc nitrogen/potentially elevated phosphorus concentrations via internal cycling processes• long hydraulic retention times• elevated sediment carbon• low sediment oxygen concentrations

Lawrence Lake, Pool 8, flooded in summer 2004 with Mississippi River water.

Lawrence Lake

m3 s

-1

0

500

1000

1500

2000

2500

3000

3500

4000

June July August

Study period

16June04

18June04

21June04

23June04

25June04

28June04

30June04

NO

3-N

m

g L-1

0

1

2

3

4

5

6

7

8

Main Channel

Lake

Peak Discharge~3500 m3/s

Max. NO3- concentration

~7 mg/l during flood

N-loss during flood ~18 mt (in ~ 14 days)

Hypothetical spatial distribution of N and P across the floodplain at base and flood stage

Hypothetical Phosphorus Concentrations

River StageBase flow Flood

Con

cent

ratio

n

0

1

2

3

4

5

6SRP Main ChannelSRP FloBWSRP IsoBWTP Main Channel TP FloBWTP IsoBW

Hypthetical Nitrogen Concentrations

River StageBase flow Flood

Con

cent

ratio

n

0

1

2

3

4

NO3 Main ChannelNO3 FloBWNO3 IsoBWTN Main ChannelTN FloBWTN IsoBW

Base flow (~ 900 m3 s-1)

Flood (6500 m3s-1)

UMR Pool 8, 2001

Close Slough

MC - MNRA

1. Characterize nutrient conditions at sites in SACN and MISS.

2. Investigate biogeochemical processes affecting nitrogen cycling (sed. ammonia accumulation, denitrification, nitrification, mineralization, NO3

- uptake [chambers and flow path]).

3. Explore spatial differences in nutrient concentrations and cycling in main channel versus backwater habitats.

4. Quantify effects of nutrient enrichment on key indicator biota and ecological processes (nutrient diffusing substrates, juv. mussel growth, community metabolism).

Project Goals – 3 yr study, 2007 – 2009

- In the St Croix (clean river) and Upper Mississippi (not so clean river).

- In Main Channels, Isolated backwaters, Flowing backwaters:

MayMay--June June 20082008

2007 (low flow only)- Site selection- Nutrient diffusing substrates- N & P concentrations

MN WRD team-Metabolism-Instantaneous loads (nutrients & sediment) -Chlorophyll

2008 (high and low flow)- N & P concentrations- N-Biogeochem- NO3 uptake (chambers)- NO3 uptake (flowpath)-Nutrient Diffusing substrates-Mussel growth chambers

MN WRD team-Metabolism-Instantaneous loads-Chlorophyll

2009 (low flow only)- N & P concentrations- N-Biogeochem- NO3 uptake (chambers)- NO3 uptake (flowpath)-Nutrient Diffusing substrates-Mussel growth chambers

MN WRD team-Metabolism-Instantaneous loads-Chlorophyll

JulJul--Aug 2007Aug 2007 JulJul--Aug Aug 20082008

JulJul--Aug Aug 20092009

Low flowLow flow Low flow Low flow Low flow Low flow R

iver

Sta

geHigh flowsHigh flows

Sampling time line and tasks

SACN Study Sites

FY08 Design- 2 non-flowing BW

(Sites 7&8);

-2 flowing BW(Sites 1&10),

-2 main channel(Sites 5 & 6)

X

Site 7 & 8

X

XSite 5

Site 6

Site 1

Site 10

X

XX

X

NO3 uptake chambers

NO3 depletion

Biogeochemistry

Mussel cages

NDS samplers

Samples

MNRA Study Sites

FY08 Design- 2 non-flowing BW

(Sites 3&4);

-2 flowing BW(Sites 8&9),

-2 main channel(Sites 5 & 6)

X

NO3 uptake chambers

NO3 depletion

Biogeochemistry

Mussel cages

NDS samplers

Samples

X

X X

XMR 6

MR 3

MR 4MR 5

MNRA Study Sites

FY08 Design- 2 non-flowing BW

(Sites 3&4);

-2 flowing BW(Sites 8&9),

-2 main channel(Sites 5 & 6)

X

NO3 uptake chambers

NO3 depletion

Biogeochemistry

Mussel cages

NDS samplers

Samples

XMR 6

X

XMR 8

MR 9

Dis

char

ger (

CFS

)

0

5000

10000

15000

20000

SACNUMR

Sampling periods

2007

DateMay Jun Jul Aug Sep

Dis

char

ge (C

FS)

0

5000

10000

15000

20000

25000

30000

UMRSACN

Sampling periods

2008

Sampling events and river discharge

2007July 23-26 -> SACN 1410 cfs, UMR1399 cfsAugust 23-25 -> SACN1440 cfs, UMR 2217 cfs

2008 May 26-28 -> SACN 4260 cfs, UMR 11070 cfsJuly 27-30 -> SACN 2430 cfs, UMR 5420 cfsAugust 24-27 -> SACN 1340 cfs, UMR 1607 cfs

Nitr

ate

(mg

L-1)

0

1

2

3

R iverSAC N U M R

Amm

oniu

m (m

g L-1

)

0

1

2

3

Tota

l N (

mg

L-1)

0

1

2

3

4

M ain Channel JulyFlow BW JulyIsoBW JulyM ain Channel AugustFlow BW AugustIsoBW August

2D Graph 7

RiverSACN UMR

NH

4- (m

g L-1

)

0

1

2

3

4

2D Graph 8

NO

3- (mg

L-1)

0

1

2

3

4

Tota

l N (

mg

L-1)

0

1

2

3

4

5

MC May 08FBW May 08IBW May 08MC Jul 08FBW Jul 08IBW Jul 08MC Aug 08FBW Aug 08IBW Aug 08

D a t eM a y J u n J u l A u g S e p O c t

Dis

char

ger (

CFS

)

0

5 0 0 0

1 0 0 0 0

1 5 0 0 0

2 0 0 0 0

S A C NU M R

S a m p l i n g p e r i o d s

2 0 0 7

D a t eM a y J u n J u l A u g S e p

Dis

char

ge (C

FS)

0

5 0 0 0

1 0 0 0 0

1 5 0 0 0

2 0 0 0 0

2 5 0 0 0

3 0 0 0 0

U M RS A C N

S a m p l i n g p e r i o d s

2 0 0 8

NitrogenNitrogenJuly and August 2007 May, July and August 2008

PhosphorusPhosphorusTo

tal P

(m

g L-1

)

0 .00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Main Channel JulyFlowBW JulyIsoBW JulyMain Channel AugFlowBW AugIsoBW Aug

RiverSACN UMR

Solu

ble

P (m

g L-1

)

0 .00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

R iverS AC N U M R

SRP

(mg

L-1)

0 .00

0 .05

0.10

0.15

0.20

0.25

Tota

l P (m

g L-1

)

0 .00

0 .05

0.10

0.15

0.20

0.25

0.30

M ain C hannel M ay 08F low BW M ay 08IsoBW M ay 08M ain C hannel Ju l 08F loB W Ju l 08IsoBW Ju l 08M ainC hannel Aug 08F loB W A ug08IsoBW A ug 08

M ay July

Aug

July and August 2007 May, July and August 2008

D a t eM a y J u n J u l A u g S e p O c t

Dis

char

ger (

CFS

)

0

5 0 0 0

1 0 0 0 0

1 5 0 0 0

2 0 0 0 0

S A C NU M R

S a m p l i n g p e r i o d s

2 0 0 7

D a t eM a y J u n J u l A u g S e p

Dis

char

ge (C

FS)

0

5 0 0 0

1 0 0 0 0

1 5 0 0 0

2 0 0 0 0

2 5 0 0 0

3 0 0 0 0

U M RS A C N

S a m p l i n g p e r i o d s

2 0 0 8

X Data

SACN UMR

Amb.

Den

itrifi

catio

n( μ

g N

cm

-2 h

r-1)

0

5

10

15

20 MC May 08FBW May 08 IBW May 08

MC Jul 08FBW Jul 08IBW Jul 08

X Data

SACN UMR0

5

10

15

20

+ C

Den

itrifi

catio

n( μ

g N

cm

-2 h

r-1)

X Data

SACN UMR

+N D

enitr

ifica

tion

( μg

cm-2

hr-1

)

0

5

10

15

20

RiverSACN UMR

+C+N

Den

itrifi

catio

n( μ

g cm

-2 h

r-1)

0

5

10

15

20

Sediment Denitrification(NO3

- N2O, N2)

Ambient denitrification low in all habitats

Carbon (glucose) additions have little effect

Nitrate additions strong effect, esp. in IsoBW, esp. Miss. River

Addition of both C and N not greater response than nitrate alone (no interaction effect)

May and July 2008

Summary (mid-study arm waving)

• Nutrient concentrations across the flood in the St.Croix not as expected; Upper Mississippi conformed better to the expected nutrient patterns.

• River discharge over-rides habitat-specific variation in nutrient dynamics

• Local nutrient inputs (groundwater) may play major role in backwater/side channel nitrogen dynamics

• Primary production and oxygen dynamics likely plays secondary role in nitrate and soluble phosphorus dynamics in backwaters.

Questions? Questions?

moderate NO3-very low NO3

-

higherdenitrification

low denitrification, limited by low C sedimentsand NO3

- penetration into sediments

lateral plant beds

organic-richsediment

Main ChannelBackwaters

High Flow

high NO3-low / moderate NO3

-

higherdenitrification

low denitrification, limited by low C sedimentsand NO3

- penetration into sediments

lateral plant beds

organic-richsediment

Normal & Low Flow

low low denitrificationdenitrification fueled by fueled by NONO33

-- produced via nitrificationproduced via nitrification

Current working model for hydrologic control of nitrate cycling in the UMR

moderate moderate denitrificationdenitrification fueled by fueled by NONO33

-- supplied in high watersupplied in high water

SACN

MNRA

2007D

isso

lved

Oxy

gen

(mg

L-1)

0

10

20

30

40

50

Main Channel JulyFlowBW JulyIsolatedBW JulyMain Channel AugFlowBW AugIsoBW Aug

RiverSACN UMR

PCT

Satu

ratio

n (%

)

0

100

200

300

RiverSACN UMR

+C+N

Den

itrifi

catio

n( μ

g cm

-2 h

r-1)

0

5

10

15

20

Amb.

Den

itrifi

catio

n( μ

g N

cm

-2 h

r-1)

0

5

10

15

20 MC May 08FBW May 08 IBW May 08MC Jul 08FBW Jul 08IBW Jul 08

2008

Tota

l N (

mg

L-1)

0

1

2

3

4

5

MC May 08FBW May 08IBW May 08MC Jul 08FBW Jul 08IBW Jul 08MC Aug 08FBW Aug 08IBW Aug 08

NO

3- (mg

L-1)

0

1

2

3

4

RiverSACN UMR

NH

4- (m

g L-1

)

0

1

2

3

4

DateMay Jun Jul Aug Sep Oct

Dis

char

ger (

CFS

)

0

5000

10000

15000

20000

SACNUMR

2007

DateMay Jun Jul Aug Sep

Dis

char

ge (C

FS)

0

5000

10000

15000

20000

25000

30000

UMRSACN

2008

SACN UMR

Dis

solv

ed O

xyge

n (m

g L-1

)

0

2

4

6

8

10

12

14

16

MC MayFloBW MayIsoBW MayMC JulyFloBW JulyIsoBW JulyMC AugFloBW AugIsoBW Aug

RiverSACN UMR

Dis

solv

ed O

xyge

n (m

g L-1

)

0

10

20

30

40

50

Main Channel JulyFlowBW JulyIsolatedBW JulyMain Channel AugFlowBW AugIsoBW Aug

Variation in Mississippi River discharge at La Crosse, WI

1-Sep

-991-N

ov-99

1-Jan

-001-M

ar-00

1-May

-001-J

ul-00

1-Sep

-001-N

ov-00

1-Jan

-011-M

ar-01

1-May

-011-J

ul-01

1-Sep

-011-N

ov-01

Dis

char

ge (m

3 s-1

)

0

1000

2000

3000

4000

5000

600032-year median discharge (1970-2001) actual dischargesampling events

Base flow (~ 900 m3 s-1)

Flood (6500 m3s-1)

Nutrient “Spiraling” in Streams (a cycle moving downstream)

Atom of nutrient (N, P, C) is transported downstream until uptake (and assimilation) by biota.

Upon release (excretion, dissociation) atom continues movement downstream until re-assimilated (Newbold, 1992).

Biologically diverse and productive streams have shorter spiraling lengths (Sw).

Streams with fast water velocity generally have longer Sw.

S = spiral length: average distance nutrient atom travels downstream in 1 “cycle”.

Sw = transport distance in water

SB = transport distance in biota

U = uptake

Nitrate example NO3-

Two compartment nutrient spiraling model:

NN

N

NN

Nitr

ate

(mg

L-1)

0

1

2

3

R iverSAC N UM R

Amm

oniu

m (m

g L-1

)0

1

2

3

Tota

l N (

mg

L-1)

0

1

2

3

4

M ain C hannel JulyFlow BW JulyIsoBW JulyM ain C hannel AugustFlow BW AugustIsoBW August

20072007To

tal P

(m

g L-1

)

0 .00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

M ain Channel JulyFlow BW JulyIsoBW JulyM ain Channel AugFlow BW AugIsoBW Aug

R iverSACN UM R

Solu

ble

P (m

g L-1

)

0 .00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

D a teM a y J u n J u l A u g S e p O c t

Dis

char

ger (

CFS

)

0

5 0 0 0

1 0 0 0 0

1 5 0 0 0

2 0 0 0 0

S A C NU M R

S a m p lin g p e r io d s

2 0 0 7

Phosphorus Nitrogen

2D Graph 7

RiverSACN UMR

NH

4- (m

g L-1

)

0

1

2

3

4

2D Graph 8

NO

3- (mg

L-1)

0

1

2

3

4

Tota

l N (

mg

L-1)

0

1

2

3

4

5

MC May 08FBW May 08IBW May 08MC Jul 08FBW Jul 08IBW Jul 08MC Aug 08FBW Aug 08IBW Aug 08

DateMay Jun Jul Aug Sep

Dis

char

ge (C

FS)

0

5000

10000

15000

20000

25000

30000

UMRSACN

Sampling periods

2008

RiverSACN UMR

SRP

(mg

L-1)

0.00

0.05

0.10

0.15

0.20

0.25

Tota

l P (m

g L-1

)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Main Channel May 08FlowBW May 08IsoBW May 08Main Channel Jul 08FloBW Jul 08IsoBW Jul 08MainChannel Aug 08FloBW Aug08IsoBW Aug 08

May July

Aug

Phosphorus Nitrogen

Phosphorus in rivers –

Distribution tends to be tightly linked to delivery of sediment particles

Backwater concentrations likely determined by sediment oxygen dynamics and redox conditions

Release of soluble P under anoxic conditions- backwater sediments as source of soluble P esp. during low flow conditions.

MNRA

SACN

Channel – flood plain connectivity: role of floods

-Replenishment of consumed solutes (esp. nitrate)

-Redistribution of sediments and associated nutrients (esp. soluble and sediment sorbed P)

-Redistribution of lipid-rich food particles

www.lbl.gov/Science-Articles/Archive/Nov-15-2002/flood_corn.jpg