Assessment of Eutrophication in Estuaries and Coastal Waters Eutrophication.pdf · Periodic Periodic Periodic Periodic Episodic Episodic Episodic Unknown Any Frequency High High Moderate

Assessment of Eutrophication inEstuaries and Coastal Waters

S.B. Bricker1, B. Buddemeier6, J.G. Ferreira2, D. Lipton5, A. Mason1,B. Maxwell4, A. Nobre2, P. Pacheco1, T. Simas2, S. Smith3

NJ Water Monitoring Coordinating CouncilDelaware River Basin Commission, W. Trenton, New Jersey

February 2, 2005

Neuse River Estuary, North Carolina, USA Ria Formosa coastal lagoon, Portugal

1 2 34

5Swarthmore College 6

The Problem – The Model

High algal productionLoss of water clarity Epiphyte problems

Macroalgal problems

Fish killsLoss of habitat

Human health risksLoss of Tourism

Closed fishing grounds

Loss of SAVLow D.O

Nuisance/Toxic Blooms

IncreasedN and Pconcentration

Symptoms and Consequences of Nutrient Enrichment

Nutrient Inputs Primary Secondary Consequencesand Processing Impacts Impacts of Symptoms

The ContextUS Clean Water Act of 1972, and US HarmfulAlgal Bloom and Hypoxia Research and ControlAct of 1998, EU Water Framework Directive(2000/60/EC), EU UWWTD and NitratesDirectives – Definition of Sensitive Areas andVulnerable Zones

Eutrophication is a process rather than a state

Elevated nutrient concentrations may or maynot be associated to human loading

Eutrophication may or may not be associated tohigh nutrient loads or concentrations (e.g.Cloern, Howarth et al, Tett et al)

Eutrophication is a significant problemworldwide (US, EU, Baltic, Mediterranean,Japan, Australia and elsewhere)

Key Aspects of the NEEA/ASSETS approach

The NEEA/ASSETS approach may bedivided into three parts:

Division of estuaries into homogeneous areas

Evaluation of data completenessand reliabilityApplication of indices

Tidal freshwater (<0.5 Tidal freshwater (<0.5 psupsu)) Mixing zone (0.5-25 Mixing zone (0.5-25 psupsu)) Seawater zone (>25 Seawater zone (>25 psupsu))

Spatial and temporal quality Spatial and temporal qualityof datasets (completeness)of datasets (completeness) Confidence in results Confidence in results(sampling and analytical(sampling and analyticalreliability)reliability)

Overall Human Influence (OHI) indexOverall Human Influence (OHI) indexOverall Eutrophic Condition (OEC) indexOverall Eutrophic Condition (OEC) indexDetermination of Future Outlook (DFO) indexDetermination of Future Outlook (DFO) index

PressurePressure StateState

ResponseResponse

S.B. Bricker, J.G. Ferreira, T. Simas, 2003. An integrated methodology for assessmentof estuarine trophic status. Ecological Modelling, 169: 39-60.

Overall Human Influence (OHI) - Pressure

Susceptibility Nutrient Inputs* (as %) Region H M L >50% NPS 1o from Ag

North Atlantic 0 6 12 78 0Mid Atlantic 15 7 0 91 60South Atlantic 8 9 4 100 81Gulf of Mexico12 23 2 100 85Pacific 14 18 7 89 50US Total 49 63 25 92 56Portugal 0 5 5 89 67

(Barnegat Bay – High susceptibility: low dilution and moderate flushing potentials,Nutrient inputs: ~100% nonpoint, 40% atmosp., 24% ag, 35% urban)

*as percentage of 130 US, 9 PT systems ; US:SPARROW model estimates, PT: Ferreira et al 2003

Susceptibility + Nutrient Inputs = Overall Human Influence dilution & flushing land based or oceanic

Overall Eutrophic Conditions (OEC) - State

?

??

?

?

?

?

??????????

TagusSado

Mira

MinhoMinhoLimaLima

DouroDouro

Ria de AveiroRia de Aveiro

MondegoMondego

RiaFormosa

Guadiana

Spa

inS

pain

??

?

?

OEC US PTHigh 12 0Mod. High 10 0Moderate 28 10Mod. Low 23 30Low 5 20Unknown 12 40as percent of 139 US and 10 PT systems

? UnknownHighModerate High

Moderate LowLow

Moderate

TagusSado

Mira

MinhoLima

Douro

Ria de Aveiro

Mondego

RiaFormosa

Guadiana

Spa

inS

pain

?

?

? UnknownNo ChangeWorsenImprove

DFO US PTImprove 6 40No Change 32 40Worsen 62 0Unknown 0 20as percent of 139 US and 10 PT systems

Determination of Future Outlook (DFO) - Response

Calculate mh, the expected nutrientconcentration due to land based sources(i.e. no ocean sources);

Calculate mb, the expected backgroundnutrient concentration due to the ocean(i.e. no land-based sources);

Calculate OHI as the ratio of mh/(mh+mb);

Equations are based on a simple Vollenweider approach, modified toaccount for dispersive exchange:

o

eseab s

smm =

Anthropogenic inputs Ocean inputs

Estuary

Class Thresholds

Low 0 to <0.2Moderate low 0.2 to <0.4Moderate 0.4 to < 0.6Moderate high 0.6 to < 0.8High >0.8

( )o

eoinh s

ssmm −=

Bricker et al. 2003 and Ferreira, Bricker and Simas. Application and sensitivity testing ofan eutrophication assessment method on US and EU coastal systems. Submitted L&O.

Overall Human Influence (OHI) - Pressure

Overall Eutrophic Condition (OEC) - State

1) Determine level of expression for Chl a, macroalgae,epiphytes, D.O., SAV loss and HABs for each zone(combines concentration/observance, spatialcoverage, frequency of occurrence) by logic tree

2) Determine and overall estuary expression for primary(average symptom values) and secondary (highestsymptom value) symptoms

3) Combine overall primary and secondary for overallestuary by matrix

NEEA Methodology

ASSETS Adaptations to OECExpert knowledge replaced by:• Data: Level of expression is based on data, cumulative frequency (Chl a = 90th percentile; DO = 10th percentile)

• Spatial area : determined by GIS or Grid

∑

=

n

le

zl E

AAS

1

Where:Az: Surface area of zoneAe: Total estuarine surface areaEl: Expression value at each zonen: Number of estuarine zones

Seawater zone

050

100150200250300350400450

0%10%20%30%40%50%60%70%80%90%100%

FrequencyCumulative %

Freq

uenc

y

5 10 15 20 25 3530 40 45 5550 more

Cum

ulat

ive

perc

enta

ge

Chlorophyll a concentration (µg l-1)

Seawater zone

050

100150200250300350400450

0%10%20%30%40%50%60%70%80%90%100%


Freq

uenc

y

5 10 15 20 25 3530 40 45 5550 more

Cum

ulat

ive

perc

enta

ge

Seawater zone

050

100150200250300350400450

0%10%20%30%40%50%60%70%80%90%100%


Freq

uenc

y

5 10 15 20 25 3530 40 45 5550 more5 10 15 20 25 3530 40 45 5550 more

Cum

ulat

ive

perc

enta

ge

Chlorophyll a concentration (µg l-1)

IF AND THENANDConcentration Spatial Coverage Expression ValueFrequency

Hypereutrophic

or

High

High

Moderate

Low

Very Low

High

Moderate

Low/Very Low

Any Spatial Coverage

Unknown

Periodic

Periodic

Periodic

Periodic

Episodic

Episodic

Episodic

Unknown

Any Frequency

High

High

Moderate

Moderate

High

Moderate

Low

Flag A

Flag A

1

1

0.5

0.5

1

0.5

0.25

0.5

0.5

Flags are used to identify impacts for which not enough data was available for the components. In these cases, assumptions were made based on conservative estimates that unknown spatial coverage is at least 10 percent of the zone, unknown duration is at least days, and unknown frequency is at least episodic.

Decision/Logic Example for Chl a

Matrix for Determining Overall Eutrophic ConditionOverall level of expression of eutrophic conditions

MODERATEPrimary symptoms high but problems with more

serious secondarysymptoms still not being

expressed

MODERATE HIGHPrimary symptoms high

and substantial secondary symptoms

becoming more expressed, indicating

potentially serious problems

levels indicate serious

MODERATELevel of expression of eutrophic conditions is

substantial

conditionsin causing the conditions

LOWLevel of expression of eutrophic conditions is

minimal

Low secondary symptoms

Moderate secondary symptoms

High secondary symptoms

0 0.3 0.6 1

Low

prim

ary

sym

ptom

sM

oder

ate

prim

ary

sym

ptom

sH

igh

prim

ary

sym

ptom

s

0.3

0.6

1



expressed






HIGHHigh primary and

secondary symptom

eutrophication problems


secondary symptom



substantial

HIGHSubstantial levels of eutrophic conditions

occuring with secondary symptoms indicating

serious problems



serious problems

MODERATE HIGHHigh secondary

symptoms indicate serious problems, but low primary indicates other factors may also be involved in causing





minimal




0 0.3 0.6 1

Low

prim

ary

sym

ptom

sM

oder

ate

prim

ary

sym

ptom

sH

igh

prim

ary

sym

ptom

s

0.3

0.6

1

factors may be involved factors may be involved

MODERATE LOWModerate secondary symptoms indicate

substantial eutrophic conditions, but low

primary indicates other




MODERATE LOWPrimary symptoms

beginning to indicate possible problems but still very few

secondary symptoms expressed




Overall level of expression of eutrophic conditions



expressed







substantial



minimal




0 0.3 0.6 1

Low

prim

ary

sym

ptom

sM

oder

ate

prim

ary

sym

ptom

sH

igh

prim

ary

sym

ptom

s

0.3

0.6

1



expressed







secondary symptom



secondary symptom



substantial



serious problems



serious problems







minimal




0 0.3 0.6 1

Low

prim

ary

sym

ptom

sM

oder

ate

prim

ary

sym

ptom

sH

igh

prim

ary

sym

ptom

s

0.3

0.6

1
















expressed







substantial



minimal




0 0.3 0.6 1

Low

prim

ary

sym

ptom

sM

oder

ate

prim

ary

sym

ptom

sH

igh

prim

ary

sym

ptom

s

0.3

0.6

1



expressed







secondary symptom



secondary symptom



secondary symptom



secondary symptom



substantial



serious problems



serious problems



serious problems



serious problems





conditions











minimal




0 0.3 0.6 1

Low

prim

ary

sym

ptom

sM

oder

ate

prim

ary

sym

ptom

sH

igh

prim

ary

sym

ptom

s

0.3

0.6

1







primary indicates other factors may be involved factors may be involved













Determination of Future Outlook (DFO) - Response

Future outlook is based on susceptibility and projected changes innutrient pressures:

Susceptibility is thecapacity of a system todilute or flush nutrients

Nutrient pressurechanges are based onexpected populationchanges, future treatmentand remediation plansand changes inwatershed use(particularly agricultural)

Improve High

ImproveLow

ImproveLow

NoChange

NoChange

NoChange

WorsenLow

WorsenHigh

Worsen High

Future Outlook For Eutrophic Conditions

Future Nutrient PressuresDecrease No Change Increase

Hig

hM

oder

ate

Low

Susc

eptib

ility

Grade 5 4 3 2 1OHI Low Moderate

lowModerate Moderate

highHigh

OEC Low Moderatelow

Moderate Moderatehigh

High

DFO Improve high Improvelow

No change Worsen low Worsen high

Metric Combination matrix Class

P

S

R

5 5 5 4 4 45 5 5 5 5 55 4 3 5 4 3

High (5%)

P

S

R

5 5 5 5 5 5 5 4 4 4 4 4 3 3 3 3 3 35 5 4 4 4 4 4 5 5 4 4 4 5 5 5 4 4 42 1 5 4 3 2 1 2 1 5 4 3 5 4 3 5 4 3

Good (19%)

P

SR

5 5 5 5 5 4 4 4 4 4 4 4 3 3 3 3 3 3 3 2 2 2 2 2 2 2 2 2 1 13 3 3 3 3 4 4 3 3 3 3 3 5 5 4 4 3 3 3 4 4 4 4 4 3 3 3 2 3 32 1 5 4 3 2 1 5 4 3 2 1 2 1 2 1 5 4 3 5 4 3 2 1 5 4 3 5 5 4

Moderate(32%)

P

S

R

4 4 4 4 4 3 3 3 3 3 3 3 2 2 2 2 2 2 1 1 1 1 12 2 2 2 2 3 3 2 2 2 2 2 3 3 2 2 2 2 3 3 3 2 25 4 3 2 1 2 1 5 4 3 2 1 2 1 4 3 2 1 3 2 1 5 4

Poor (24%)

P

S

R

3 3 3 3 3 2 2 2 2 2 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1 2 2 2 1 1 1 1 15 4 3 2 1 5 4 3 2 1 3 2 1 5 4 3 2 1

Bad (19%)

Grades for OHI, OECand DFO arecombined into agrade of High, Good,Moderate, Poor andBad with color codingto match the EU WFDconvention.

Combinations weredistributedheuristically andimpossible orimprobablecombinations wereexcluded.

Additional Adaptation: Synthesis of OHI - OEC - DFO

Barnegat Bay – NEEA/ASSETS ApplicationIndices

Overall HumanInfluence (OHI)

ASSETS: 1

OverallEutrophicCondition (OEC)

ASSETS: 1

Determination ofFuture Outlook(DFO)ASSETS: 4

Methods

Susceptibility

Nutrient inputs

Primary

Secondary

Future nutrientpressures

Parameters Rating Level ofexpression

Dilution potential Low Highsusceptibility

Flushing potential Moderate

High nutrient input

Chlorophyll a HighEpiphytes No Data High Macroalgae Moderate

Dissolved Oxygen No Problem Submerged Aquatic Moderate HighVegetationNuisance and Toxic HighBlooms

Future nutrient pressures decrease

Index

HIGH

HIGH

IMPROVELOW

ASSETS: BAD

Chlorophyll aHABs

Macroalgae

Population (X 103) 588- 800Nutrient loading (tN y-1) 720Mean depth (m) 1.4Mean tidal range (m) 0.9Water residence time (d) 27-71

Main impacts:Estuary Characteristics:

Ria Formosa – NEEA/ASSETS ApplicationIndices

Overall HumanInfluence (OHI)

ASSETS: 3


ASSETS: 4

Determination ofFuture Outlook(DFO)ASSETS: 4

Methods

Susceptibility

Nutrient inputs

Primary

Secondary

Future nutrientpressures

Parameters Rating Level ofexpression

Dilution potential High Moderatesusceptibility

Flushing potential Low

Moderate nutrient input

Chlorophyll a LowEpiphytes Moderate ModerateMacroalgae High

Dissolved Oxygen No ProblemSubmerged Aquatic LowVegetation LowNuisance and Toxic No ProblemBlooms

Future nutrient pressures decrease

Index

MODERATE

MODERATELOW

IMPROVELOW

ASSETS: GOOD

MacroalgaeIntertidal O2

Bivalve mortality

Population (X 103) 124-211Nutrient loading (tN y-1) 1028Mean depth (m) 1.9Mean tidal range (m) 2Water residence time (d) 0.5-2

Estuary Characteristics: Main impacts:

Classification based on physical andhydrologic characteristics – nutrients will beprocessed differently in systems that flush wellor flush poorly and management strategies willbe different

A top-down classification resulted in 7 types.DISCO gives 6 types but semi-enclosedlagoons were not included

TagusSado

Mira

MinhoLima

Douro

Ria de Aveiro

Mondego

RiaFormosa

Guadiana

Spa

inS

pain

A top-down classification resulted in 14 types.DISCO gives 10 types (120 of 138 within 6 types).Characteristics: Mean depth; % open mouth; Tide height;log (freshwater flow/area); Mean air temperature.

Typology: DISCO Cluster Results

Typology: Ecosystem Reality

Symptom level

Freq

uenc

y(s

patia

l/tem

pora

l var

iabi

lity)

Naturalconditions

Stressors(pressure)

Threshold A

A

B

C

Threshold C

A

B

C

Typology: Reference Conditions

14 small tidally flushed embayments in Maine arecategorized and normalized for residence time.

Thresholds for nutrient loading (TN) and referenceconditions for D.O. are different for different systems

depending upon residence time.

Similarly, Chl a ranges for classification ofstatus vary by type

Chlorophyll a (ug/l) Sensitive NEEA SystemsHypereutrophicHypereutrophic >60 >5High 20 - 60 2 - 5Medium 5 - 20 1 - 2Low 0 - 5 0 - 1

NEEA/ASSETS applied Chl a ranges universally, however, for sensitive systems, e.g. Florida Bay,5 ug/l indicates severe problems.

From: Latimer and Kelly. 2003. Proposed classification for predictingsensitivity of coastal receiving waters to effects of nutrients. US EPA.

Socioeconomic Pilot: Fish Catch & Water Quality

This indicator will provide insight to the consequences of eutrophication andprovide justification for management action

Premise: Fish catch will decrease as water quality declines, economic losses resultStudy: Compares fish catch among 13 sites (9 in Gulf of Maine, Narragansett, LongIsland Sound, Patuxent and Potomac Rivers) with different water quality (D.O.)

Nitrogen Loading to LIS

60000

70000

80000

90000

100000

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

Tota

l Nitr

ogen

(Kg/

day)

90,248

65,852

~30% reduction

Long Island Sound DO (Corrected Oxygen) 10th %

3

4

5

6

7

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

YEAR

DO (C

orre

cted

O

xyge

n)

DO (Corrected Oxygen) 10th %

3.8

6.4~40% increase

~30% Reduction in Nitrogen Loading~40% Increase of DO 10th PercentileSignificant Increase in Striped Bass Catch Rate

Long Island Sound Mean Striped Bass Catch Rate

y = 0.112x + 0.7776 R2 = 0.6451

0

0.5

1

1.5

2

1993 1994 1995 1996 1997 1998 1999 2000

YEARM

ean

Cat

ch (f

ish

catc

h pe

r fis

herm

an p

er tr

ip) Mean Striped Bass Catch

No

Dat

a

From A. Mason ASLO 2004 presentation: Improving indicatorsof water quality degradation impacts for management ofestuaries and coastal

Modelgreenscenari

o

Ria Formosa –ASSETS validation & model scenariosIndex


ASSETS OEC: 4


ASSETS OEC: 4


ASSETS OEC:

Methods

PSM

SSM

PSM

SSM

PSM

SSM

Parameters Value Level ofexpressionChlorophyll a 0.25Epiphytes 0.50 0.57Macroalgae 0.96 Moderate

Dissolved Oxygen 0Submerged Aquatic 0.25 0.25Vegetation LowNuisance and Toxic 0Blooms

Chlorophyll a 0.25Epiphytes 0.50 0.58Macroalgae 1.00 Moderate


Chlorophyll a 0.25Epiphytes 0.50 0.42Macroalgae 0.50 Moderate


Field data

Researchmodel

Index

MODERATELOW

MODERATELOW

MODERATELOW

28% lower

4(5)

Nobre, Ferreira, Newton, Simas, Icely, Neves. Managing eutrophication: Integration of field data,ecosystem-scale simulations and screening models. Submitted L&O. (www.eutro.org)

TagusSado

Mira

MinhoLima

Douro

Ria de Aveiro

Mondego

RiaFormosa

Guadiana

Spa

inS

pain

?

?

? UnknownNo ChangeWorsenImprove

DFO US PTImprove 6 40No Change 32 40Worsen 62 0Unknown 0 20as percent of 139 US and 10 PT systems

Determination of Future Outlook (DFO) - Pressure

Response: Management, Monitoring & Research

• NEEA/ ASSETS is a transferable methodology to evaluate eutrophicationstatus, influencing factors, and future outlook for guidance and prioritizationof management resources

• Improvements have been made to the original method, however, additionalmodifications are necessary and are in progress

•Application of the method shows Barnegat Bay to be highly eutrophic (Bad)

• Additional improvements will improve accuracy: -- development of typology, -- re-evaluation of thresholds for indicator variables and inputs for

different types of estuaries, -- re-evaluation of variables, use core for all systems, additional

variables as appropriate by type, -- addition of socio-economic indicator, -- development of models/tools to predict the impact of different management scenarios

Concluding Remarks

Concluding Remarks

Assessment method improvements are the focus ofNOAA’s National Estuarine Eutrophication Assessment Update Program

which includes national and international partners

http://www.eutro.org

Documents

Assessment of Eutrophication in Estuaries and Coastal Waters Eutrophication.pdf · Periodic Periodic Periodic Periodic Episodic Episodic Episodic Unknown Any Frequency High High Moderate