Algal metric approaches for Algal metric approaches for assessingassessing trophic condition trophic condition and organic enrichment in and organic enrichment in U.S. streams and riversU.S. streams and rivers

Stephen D. PorterStephen D. PorterNorman E. SpahrNorman E. SpahrDavid K. MuellerDavid K. MuellerMark D. MunnMark D. MunnNeil M. DubrovskyNeil M. Dubrovsky

NWQMC MeetingNWQMC MeetingMay 10, 2006May 10, 2006

San Jose, CASan Jose, CA

EPA National Water Quality InventoryEPA National Water Quality Inventory (305b Report to Congress)(305b Report to Congress)

Causes of water-quality impairmentCauses of water-quality impairment• SiltationSiltation• NutrientsNutrients• Oxygen-depleting substancesOxygen-depleting substances

Sources of water-quality impairmentSources of water-quality impairment• Nonpoint-source runoff from urban & agricultural landNonpoint-source runoff from urban & agricultural land

EPA Nutrient Criteria – Streams and Rivers EPA Nutrient Criteria – Streams and Rivers (U.S. EPA, 2000)(U.S. EPA, 2000)

Primary VariablesPrimary Variables• Nutrients Nutrients (TN & TP)(TN & TP)• Algal Biomass Algal Biomass (chlorophyll (chlorophyll aa))• Water Clarity Water Clarity (turbidity, transparency, total suspended solids)(turbidity, transparency, total suspended solids)

Secondary Response VariablesSecondary Response Variables• Stream Metabolism—DO, pHStream Metabolism—DO, pH• Biological Attributes Biological Attributes (autecology, nature of response, grazers, IBIs)(autecology, nature of response, grazers, IBIs)

Why are algae important for assessing water quality?Why are algae important for assessing water quality?

Objectives and Scope

1. Which algal metrics are most useful for assessing nutrient and organic enrichment in streams and rivers?

2. How well do these metrics correlate with nutrient concentrations Nationally? Regionally?

3. Do the algal metrics discriminate among land-use categories?

4. How do algal metric scores respond along nutrient and land-use gradients?

5. Does algal biovolume (biomass, chlorophyll) vary significantly with nutrient concentrations, land-use conditions, or among major water-resource regions?

Do algal metrics and nutrient concentrations provide complementary information about the effects of land-use practices on water quality?

How do trophic boundaries derived from USGS How do trophic boundaries derived from USGS biovolume data compare with proposed nutrient criteria?biovolume data compare with proposed nutrient criteria?

NutrientsNutrients• Nitrogen: N-fixing algae, N-heterotrophsNitrogen: N-fixing algae, N-heterotrophs• N & P: eutrophic diatoms and soft (non-diatom) algaeN & P: eutrophic diatoms and soft (non-diatom) algae

Organic EnrichmentOrganic Enrichment• Pollution Tolerance (saprobien system; nutrients+carbon)Pollution Tolerance (saprobien system; nutrients+carbon)• Dissolved oxygen requirements; tolerance to low DODissolved oxygen requirements; tolerance to low DO

Major IonsMajor Ions• Salinity (specific conductance); alkalinity (hardness); certain metalsSalinity (specific conductance); alkalinity (hardness); certain metals

PhyPhysical Propertiessical Properties (pH, temperature, velocity, light, etc.) (pH, temperature, velocity, light, etc.)

Indicators of algal biomassIndicators of algal biomass• Chlorophyll Chlorophyll aa, Ash-free Dry Mass, , Ash-free Dry Mass, BiovolumeBiovolume

Indicators of water quality and trophic conditionIndicators of water quality and trophic condition• QualitativeQualitative – published literature accounts (~ 100 y history) – published literature accounts (~ 100 y history)

Algal MetricsAlgal Metrics......aggregation of species with similar autecological propertiesaggregation of species with similar autecological properties

AutecologyAutecology……physiological requirements or tolerance range of speciesphysiological requirements or tolerance range of species

Periphyton collection methodsPeriphyton collection methods

-1.0 -0.5 0.0 0.5 1.0

PCA (1)

-1.0

-0.5

0.0

0.5

1.0

NF_YS

SL_HB

ON_NH

TR_E

PC_MT

OT_AH

-1.0 -0.5 0.0 0.5 1.0

PCA (1)

-1.0

-0.5

0.0

0.5

1.0

PC

A (

2)

NF_YS

ES_SF

SL_FRTR_OSP_OL

ON_AL

SP_PSOT_VL

OT_AHPT_LB

TR_M

PT_TB

PT_VT

PC_MT

TR_E

SL_FB

PC_LT

ON_AH

OT_MD

EUTROPHIC

SP_AM

ON_NH

SP_BM

PC_SN

OT_FH

SL_HB

PT_LA

OT_LWSP_AP

Which algal metrics are most useful for assessment?Which algal metrics are most useful for assessment?

PC_MTPC_MT Tolerant DiatomsTolerant Diatoms—Indicator of nutrient & organic enrichment—Indicator of nutrient & organic enrichment

ON_NHON_NH Nitrogen HeterotrophsNitrogen Heterotrophs—Indicator of organic nitrogen enrichment—Indicator of organic nitrogen enrichment

TR_ETR_E Eutrophic DiatomsEutrophic Diatoms—Indicator of nutrient enrichment—Indicator of nutrient enrichment

SL_HBSL_HB Halobiontic DiatomsHalobiontic Diatoms—Indicator of dissolved constituents—Indicator of dissolved constituents

NF_YSNF_YS Nitrogen FixersNitrogen Fixers—Indicator of low nitrogen or N:P ratios—Indicator of low nitrogen or N:P ratios

OT_AHOT_AH High DO IndicatorsHigh DO Indicators—Indicator of high dissolved oxygen concentrations—Indicator of high dissolved oxygen concentrations

Geographic regions based on aggregations of Water-Resource RegionsGeographic regions based on aggregations of Water-Resource Regions

Halobiontic DiatomsHalobiontic Diatoms

RegionRegion

0.00.0

0.20.2

0.40.4

0.60.6

0.80.8

1.01.0

Sp

ea

rma

n C

orr

ela

tion

Co

eff

icie

nt

Sp

ea

rma

n C

orr

ela

tion

Co

eff

icie

nt

11 22 33 44 55 66 77 88

912912923923

TNTNTPTP

180180182182

121121120120

248248249249

60607070

81818080

79797979

103103103103

40404040

NatNat

0.00.0

0.20.2

0.40.4

0.60.6

0.80.8

1.01.0

11 22 33 44 55 66 77 88NatNat

TNTP

912923

180182

121120

248249

6070

8180

7979

103103

4040

Tolerant DiatomsTolerant Diatoms

912923

TNTP

180182

121120

248249

6070

8180

7979

103103

4040

0.20.2

0.40.4

0.60.6

0.80.8

1.01.0

Sp

ea

rma

n C

orr

ela

tion

Co

eff

icie

nt

Sp

ea

rma

n C

orr

ela

tion

Co

eff

icie

nt

11 22 33 44 55 66 77 88NatNat

Nitrogen HeterotrophsNitrogen Heterotrophs

912923

TNTP

180182

121120

248249

6070

8180

7979

103103

4040

0.00.0

0.20.2

0.40.4

0.60.6

0.80.8

1.01.0

11 22 33 44 55 66 77 88NatNat

EutrophicEutrophic DiatomsDiatoms

How well do “tolerant” algal metrics correlate with nutrients?How well do “tolerant” algal metrics correlate with nutrients?

Total NitrogenTotal NitrogenTotal PhosphorusTotal Phosphorus

912923

TNTP

180182

121120

248249

6070

8180

7979

103103

4040

Nitrogen FixersNitrogen Fixers

NatNat

RegionRegion

-0.5-0.5

-0.3-0.3

-0.1-0.1

0.10.1

0.30.3

0.50.5

11 22 33 44 55 66 77 88NatNat

RegionRegion

-0.5-0.5

-0.3-0.3

-0.1-0.1

0.10.1

0.30.3

0.50.5

11 22 33 44 55 66 77 88

180182

912923

121120

248249

6070

8180

103103

4040

7979

TNTP

High DO IndicatorsHigh DO Indicators

NatNat

RegionRegion

-0.5-0.5

-0.3-0.3

-0.1-0.1

0.10.1

0.30.3

0.50.5

11 22 33 44 55 66 77 88

High DO IndicatorsHigh DO Indicators

NatNat

RegionRegion

-0.5-0.5

-0.3-0.3

-0.1-0.1

0.10.1

0.30.3

0.50.5

11 22 33 44 55 66 77 88

Nitrogen FixersNitrogen Fixers

NitrateNitrateOrthophosphateOrthophosphate

How well do “sensitive” algal metrics correlate with nutrients?How well do “sensitive” algal metrics correlate with nutrients?

Total NitrogenTotal NitrogenTotal PhosphorusTotal Phosphorus

Sp

ea

rma

n C

orr

ela

tion

Co

eff

icie

nt

Sp

ea

rma

n C

orr

ela

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Co

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nt

Sp

ea

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n C

orr

ela

tion

Co

eff

icie

nt

Sp

ea

rma

n C

orr

ela

tion

Co

eff

icie

nt

What do algal metrics tell us about land use?What do algal metrics tell us about land use?

Undev

Undev

Parti

al

Parti

al

AgAg

Urb

anU

rban

Mix

edM

ixed

Larg

eLa

rge

Land CoverLand Cover

00

2020

4040

6060

8080

100100

ON

_NH

ON

_NH

(re

lativ

e ab

unda

nce)

(re

lativ

e ab

unda

nce)

cc bb aa aa aa aa

Und

ev

Und

evPar

tial

Partia

l

AgAg

Urb

anU

rban

Mix

edM

ixed

Larg

eLa

rge

Land CoverLand Cover

00

2020

4040

6060

8080

100100

TR

_ET

R_E

(re

lativ

e ab

unda

nce)

(re

lativ

e ab

unda

nce)

cc aa aabb aa aabb

Und

evU

ndev

Par

tial

Par

tial

AgAg

Urb

anU

rban

Mix

edM

ixed

Larg

eLa

rge

Land CoverLand Cover

00

2020

4040

6060

8080

100100

SL

_HB

SL

_HB

(re

lativ

e ab

unda

nce)

(re

lativ

e ab

unda

nce)

dd cc aabb bbcc aa aa

Und

evU

ndev

Par

tial

Par

tial

AgAg

Urb

anU

rban

Mix

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ixed

Larg

eLa

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Land CoverLand Cover

00

2020

4040

6060

8080

100100

PC

_MT

PC

_MT

(re

lativ

e ab

unda

nce)

(re

lativ

e ab

unda

nce) dd cc aabb aa aabb bbcc

Nitrogen HeterotrophsNitrogen Heterotrophs Tolerant DiatomsTolerant Diatoms

Halobiontic DiatomsHalobiontic Diatoms Eutrophic DiatomsEutrophic Diatoms

What do nutrient concentrations tell us about land use?What do nutrient concentrations tell us about land use?

Undev

Partial

AgUrban

Mixed

Large

Land Cover

0

5

10

15

20

To

tal

Nit

rog

en

(m

g/L

)

c b a a a a

Undev

Undev

Partia

l

Partia

l

AgAg

Urb

an

Urb

anM

ixed

Mix

ed

Larg

e

Larg

e

Land CoverLand Cover

00

55

1010

1515

Nit

rite

+ N

itra

te N

itro

ge

nN

itri

te +

Nit

rate

Nit

rog

en

(m

g/L

) (

mg

/L)

cc bb aa aa aa bb

Undev

Undev

Partia

l

Partia

lAgAg

Urban

Urban

Mixe

d

Mixe

d

Larg

e

Larg

e

Land CoverLand Cover

00

11

22

33

To

tal

Ph

osp

ho

rus

To

tal

Ph

osp

ho

rus

(mg/

L) (

mg/

L)

dd cc aabb aabb aa bbcc

Undev

Undev

Partia

l

Partia

l

AgAg

Urb

an

Urb

an

Mixe

d

Mixe

dLa

rge

Larg

e

Land CoverLand Cover

0.00.0

0.50.5

1.01.0

1.51.5

2.02.0

Ort

ho

ph

osp

hat

eO

rth

op

ho

sph

ate

(mg/

L) (

mg/

L)

dd cc aabb aabb aa bbcc

Total NitrogenTotal Nitrogen Total PhosphorusTotal Phosphorus

Nitrite + NitrateNitrite + Nitrate OrthophosphateOrthophosphate

Algae = NutrientsAlgae = Nutrients

Nutrients better Nutrients better than Algaethan Algae

Nutrients better Nutrients better than Algaethan Algae

Neither AlgaeNeither Algaenor Nutrientsnor Nutrients

How well do algal metrics & nutrients discriminate betweenHow well do algal metrics & nutrients discriminate betweenundeveloped and developed stream basins?undeveloped and developed stream basins?

00 33 66 99 1212 1515

Total Nitrogen (mg/L)Total Nitrogen (mg/L)

00

2020

4040

6060

8080

100100P

erc

en

tag

e o

f e

utr

op

hic

dia

tom

sP

erc

en

tag

e o

f e

utr

op

hic

dia

tom

s

0 11 22 33 44 55

Orthophosphate (mg/L)Orthophosphate (mg/L)

00

2020

4040

6060

8080

100100

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

0 33 66 99 1212 1515

Nitrite + Nitrate Nitrogen (mg/L)Nitrite + Nitrate Nitrogen (mg/L)

00

2020

4040

6060

8080

100100

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

0 11 22 33 44 55

Total Phosphorus (mg/L)Total Phosphorus (mg/L)

00

2020

4040

6060

8080

100100

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

How do algal-metric scores respond along nutrient gradients?How do algal-metric scores respond along nutrient gradients?

RMSE = 18.7 (94%)RMSE = 18.7 (94%)n = 912n = 912

RMSE = 19.1 (97%)RMSE = 19.1 (97%)n = 973n = 973

RMSE = 19.0 (96%)RMSE = 19.0 (96%)n = 922n = 922

RMSE = 19.2 (98%)RMSE = 19.2 (98%)n = 973n = 973

Per

cent

age

of e

utro

phic

dia

tom

sP

erce

ntag

e of

eut

roph

ic d

iato

ms

0 2020 4040 6060 8080 100100

Percentage of urban land (ag < 25%)Percentage of urban land (ag < 25%)

00

2020

4040

6060

8080

100100

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

0 2020 4040 6060 8080 100100

Percentage agricultural land (urban < 5%)Percentage agricultural land (urban < 5%)

00

2020

4040

6060

8080

100100

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

Pe

rce

nta

ge

of

eu

tro

ph

ic d

iato

ms

RMSE = 16.7 (100%)RMSE = 16.7 (100%)n = 634n = 634

RMSE = 18.7 (118%)RMSE = 18.7 (118%)n = 505n = 505

How do algal-metric scores respond along land-use gradients?How do algal-metric scores respond along land-use gradients?

11 22 33 44 55 66 77 88

RegionRegion

0.00010.0001

0.0010.001

0.010.01

0.10.1

11

1010

100100

10001000

Bio

volu

me

(cm

Bio

volu

me

(cm

33 /m/m

22 ))

AgAgLargeLarge

Mixed

Mixed

Partial

Partial

UndevUndev

UrbanUrban

Land UseLand Use

Algal biovolume relations with geographic Algal biovolume relations with geographic region, water quality, and land useregion, water quality, and land use

MedianMedian

National:National: ( (positive relation) Nitrate (positive relation) Nitrate (= 0.179, p<0.001)= 0.179, p<0.001) (negative relation) Suspended Sediment ((negative relation) Suspended Sediment ( = -0.168, p=0.001) = -0.168, p=0.001)

Regions 4, 7, & 8:Regions 4, 7, & 8: (positive relation) TN, Nitrate, TP ((positive relation) TN, Nitrate, TP ( > 0.3) > 0.3)

Region 5:Region 5: (negative relation) Suspended Sediment, TP ((negative relation) Suspended Sediment, TP ( < -0.4) < -0.4)

11 22 33 44 55 66 77 88

RegionRegion

0.00010.0001

0.0010.001

0.010.01

0.10.1

11

1010

100100

10001000

Bio

volu

me

(cm

Bio

volu

me

(cm

33 /m/m

22 ))

AgAgLargeLarge

Mixed

Mixed

Partial

Partial

UndevUndev

UrbanUrban

Land UseLand Use

EutrophicEutrophicMesotrophicMesotrophicOligotrophicOligotrophic

Estimating trophic boundary conditionsEstimating trophic boundary conditions

OligotrophicOligotrophic--MesotrophicMesotrophic 1.351.35 2121 2020MesotrophicMesotrophic--EutrophicEutrophic 1515 6666 7070

BiovolumeBiovolume(cm(cm33/m/m22))

est.est. CHLa CHLa(mg/m(mg/m22))

Dodds et al. (1998)Dodds et al. (1998)benthic benthic CHLaCHLa

(mg/m(mg/m22))

< 1.35

1.35 – 5.67

5.68 – 15

> 15.01

Distribution of algal biovolumeDistribution of algal biovolume

, cm3/m2

Distribution of eutrophic diatomsDistribution of eutrophic diatoms

Eutrophic Diatoms, percent

Distribution of nitrogen-fixing algaeDistribution of nitrogen-fixing algae

Nitrogen Fixers, percent

Summary & ConclusionsSummary & Conclusions

1. What do algal metrics tell us about water quality?1. What do algal metrics tell us about water quality?

2. What does algal biovolume tell us about water quality?2. What does algal biovolume tell us about water quality?

Strong correlation with nutrient concentrationsStrong correlation with nutrient concentrationsDiscrimination between developed & undeveloped basinsDiscrimination between developed & undeveloped basinsResponses along nutrient and land-use gradientsResponses along nutrient and land-use gradients

Weak correlation with nutrient and sediment concentrationsWeak correlation with nutrient and sediment concentrationsNo significant differences among land-use or regional categoriesNo significant differences among land-use or regional categories

Algal biomass may be controlled more by antecedent hydrologic Algal biomass may be controlled more by antecedent hydrologic disturbance, shading, or biological interactions (e.g. grazers) than disturbance, shading, or biological interactions (e.g. grazers) than land-use practices or nutrient concentrations. Local scale response.land-use practices or nutrient concentrations. Local scale response.

Distribution of algal tolerance indicators corresponds with Distribution of algal tolerance indicators corresponds with major agricultural and urban areas.major agricultural and urban areas.

3. How can algal indicators of stream condition be applied to3. How can algal indicators of stream condition be applied to nutrient and biological criteria? nutrient and biological criteria?

Summary & ConclusionsSummary & Conclusions

Autecological metrics reflect responses to eutrophication processesAutecological metrics reflect responses to eutrophication processesBiovolume (standing crop)—hydrology relations Biovolume (standing crop)—hydrology relations (days of accrual)(days of accrual)

Indicators of organic enrichment Indicators of organic enrichment

Algal data available from NAWQA Data WarehouseAlgal data available from NAWQA Data WarehouseTaxonomic consistency: ANSP Taxonomic consistency: ANSP http://diatom.acnatsci.org/nawqa/Autecology: NAWQA Algal Attributes tableAutecology: NAWQA Algal Attributes tableData Analysis: Algal Data Analysis System (ADAS—T.F. Cuffney)Data Analysis: Algal Data Analysis System (ADAS—T.F. Cuffney)

PhycoAide (ANSP)PhycoAide (ANSP)

Stephen D. PorterStephen D. PorterUSGS—Water ResourcesUSGS—Water ResourcesNAWQA National SynthesisNAWQA National SynthesisBox 25046, MS406, DFCBox 25046, MS406, DFCDenver, CO 80225Denver, CO 80225

sdporter@usgs.govsdporter@usgs.gov303-445-4647303-445-4647

Literature CitedLiterature Cited

Dodds, W.K., Jones, J.R., and Welch, E.B., 1998, Suggested classification of streamDodds, W.K., Jones, J.R., and Welch, E.B., 1998, Suggested classification of streamtrophic state: Distributions of temperate stream types by chlorophyll, total trophic state: Distributions of temperate stream types by chlorophyll, total nitrogen, and phosphorus. Water Resources, v. 32, no. 5, p. 1455-1462.nitrogen, and phosphorus. Water Resources, v. 32, no. 5, p. 1455-1462.

U.S. Environmental Protection Agency, 2000, Nutrient criteria technical guidance manual. U.S. Environmental Protection Agency, 2000, Nutrient criteria technical guidance manual. Rivers and Streams. Washington, D.C.: U.S. Environmental Protection Agency, Rivers and Streams. Washington, D.C.: U.S. Environmental Protection Agency, Office of Water, EPA-822-B-00-002, 240 p.Office of Water, EPA-822-B-00-002, 240 p.