Mark D. Munn NAWQA Nutrient Effects Team Leader USGS Washington Water Science Center Tacoma, WA

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Nutrient-Biota Interactions in Agriculturally Dominated Landscapes: Lessons from the USGS National Water-Quality Assessment (NAWQA) Program. Mark D. Munn NAWQA Nutrient Effects Team Leader USGS Washington Water Science Center Tacoma, WA. Nutrient Enrichment Effects on Stream Ecosystems. - PowerPoint PPT Presentation

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Nutrient-Biota Interactions in Agriculturally Dominated Landscapes: Lessons from the USGS National Water-Quality Assessment

(NAWQA) Program

Mark D. MunnNAWQA Nutrient Effects Team Leader

USGS Washington Water Science CenterTacoma, WA

Nutrient Enrichment Effects on Stream Ecosystems

Determine how biological communities and processes respond to varying levels of nutrient enrichment in streams from contrasting environmental settings.

1. Biological communities: nutrients, habitat, algae and invertebrates

2. Stream metabolism: dissolved oxygen production

3. Nitrogen cycling: transport, transformations, uptake

GeorgiaNebraska

Delaware

Indiana

Washington

EPA Nutrient Indicators

• Chlorophyll a*• Algal AFDW• Community

composition• Community metrics• Production/respiration• Secondary production• pH• DO

• Hydrologic studies• Nitrogen*• Phosphorus*• Nutrient ratios• Sediment composition• Temperature• Transparency/TSS*

Chlorophyll a [rock/wood, silt/sand, or seston]

NUTRIENT GRADIENT

BIO

LO

GIC

AL

RE

SP

ON

SE

Nutrient Gradient – Response Conceptual Model

Threshold

oligotrophic

eutrophic

IN and NE exceeded TP threshold

Phosphorus Gradient (TP mg/L)

0.001 0.01 0.1 1 10

Stu

dy

Un

its

DE

GA

IN

NE

WA

Nitrogen Gradient (TN mg/L)

0.01 0.1 1 10 100

Stu

dy

Un

it

DE

GA

IN

NE

WA

All study units exceeded nitrogen threshold

TN exceeded proposed EPA criteria at 76 to 96% of sites

0.7

1.5

Study Unit

WA NE IN GA DE

TN

(m

g/L

)

0

5

10

20

22

0.880.38 2.18 0.69 0.7176% 96% 87% 83% 96%

Proposed EPA Nutrient Criteria

TP exceeded proposed EPA criteria at 52 to 100% of sites

Study Unit

WA NE IN GA DE

TP

(m

g/L

)

0.0

0.5

1.0

1.5

2.02.53.0

Proposed EPA Nutrient Criteria

0.022 0.067 0.076 0.037 0.03193% 100% 67% 52% 89%

Seston CHLa exceeded proposed EPA criteria at 11 to 93% of sites

10

Study Unit

WA NE IN GA DE

Ses

ton

CH

La

(ug

/L)

0

20

40

60

80Proposed EPA Nutrient Criteria

1.78 3 2.7 0.93 3.7541% 93% 11% 32% 28%

Chlorophyll a varied by substrate

WA NE IN GA DE

Ben

thic

CH

La

(mg

/m2)

0

20

40

60

80

100

Rock-WoodSilt-Sand

National TP-CHLa relationship exists, …

TP (mg/L)

0.001 0.01 0.1 1 10

Ses

ton

Ch

loro

ph

yll

a (u

g/L

)

0.1

1

10

100r2 = 0.11

…but distinct regional differences.

TP (mg/L)

0.001 0.01 0.1 1 10

Ses

ton

Ch

loro

ph

yll a

(u

g/L

)

0.1

1

10

100GAWANEDE IN

Seston CHLa vs TP and TN in GA

0.010

0.100

1.0

10.0

TP (mg/L)

1.0 10.0

1.0

10.0

TN (mg/L)

SE

ST

ON

CH

LO

RO

PH

YL

L A

(u

g/L

)

SE

ST

ON

CH

LO

RO

PH

YL

L A

(u

g/L

)

.04

0.10.10.01

Spearman (rs) correlation matrix (N=142)

Habitat limits CHLa

ROCK/WOOD

CHLa

SILT/SAND

CHLa

SESTON

CHLa

TP 0.24 0.36 0.62

TN 0.14 0.10 0.15

BASE FLOW -0.02 -0.34 -0.34

TEMPERATURE -0.34 0.13 0.23

CANOPY -0.38 -0.43 -0.42

SUBSTRATE 0.44 0.37 -0.10

BFI = Base Flow Index, the ratio of base flow to total flow volume for a given year.

NUTRIENT CONCENTRATION

CH

LO

RO

PH

YL

L A

Nutrients control algae- nutrient limitation

Algae control nutrients-low nutrients due to uptake

Nutrient saturation- possible physical controls

Algae limited by physical processes - stream flow, light, sediment, etc.

oligotrophic

eutrophic

Implications for Nutrient Criteria

1. Nutrient concentrations and chlorophyll may not always provide the best indication of stream status.

2. Agricultural streams can be nutrient saturated and habitat limited.

3. Need sub-regional and/or stream-type specific predictive models that incorporate nutrients, habitat, and biological components.

Contact Information

Mark D. MunnWashington Water Science CenterU.S. Geological SurveyTacoma, WA 98402253-428-3600 x2686mdmunn@usgs.gov

National NAWQA:http://water.usgs.gov/nawqa/

Nutrient Effects Team: http://pubs.usgs.gov/fs/fs11803/

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