The use of ASSETS and phytoplankton species The use of ASSETS and - - PowerPoint PPT Presentation

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The use of ASSETS and phytoplankton species The use of ASSETS and - - PowerPoint PPT Presentation

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The use of ASSETS and phytoplankton species The use of ASSETS and phytoplankton species composition to define type- -specific reference specific reference composition to define type conditions for estuarine water quality management conditions

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The use of ASSETS and phytoplankton species The use of ASSETS and phytoplankton species composition to define type composition to define type-

  • specific reference

specific reference conditions for estuarine water quality management conditions for estuarine water quality management

ASLO/TOS 2004, Honolulu Session SS5.13 Eutrophication of Coastal Waters February 17th 2004 http://www.eutro.org J.G.Ferreira

  • T. Simas

S.B. Bricker W.J. Wolff

  • A. Mason
  • A. Nobre
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  • Problem definition

Problem definition

  • Monotype thresholds and problems

Monotype thresholds and problems

  • Examples from a multitype world

Examples from a multitype world

  • Possible improvements to ASSETS

Possible improvements to ASSETS

  • Conclusions

Conclusions

Topics Topics

Slides

1 3 4 12+2 3 1

Guadiana estuary, Portugal

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Problem definition Problem definition

  • Coastal eutrophication assessment has traditionally been based
  • n state
  • The NEEA approach developed a PSR framework, extended by

ASSETS into an integrated PSR, resulting in a single index

  • Overall Eutrophic Condition (OEC), the NEEA/ASSETS index for

state, is based on fixed thresholds

  • NOAA, EPA, OSPAR and others recognize that a fair assessment
  • f state should consider typology
  • Other regulatory instruments such as the EU WFD require the

definition of type-specific reference conditions

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Typology reality check Typology reality check (a) regulatory reality (a) regulatory reality

Symptom level Frequency (spatial/temporal variability) Natural conditions Stressors (pressure) Thresholds

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ASSETS Monotype approach for OEC ASSETS Monotype approach for OEC

Frequency (spatial/temporal variability) Natural conditions Stressors (pressure) Natural conditions Stressors (pressure) Threshold Frequency (spatial/temporal variability) Threshold Symptom 1 Spatial weighting Temporal weighting OEC Symptom 1 level Symptom 2 Spatial weighting Temporal weighting S.B. Bricker, J.G. Ferreira, T. Simas, 2003. An integrated methodology for assessment

  • f estuarine trophic status.

Ecological Modelling, 169(1), 39-60. Symptom 2 level

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SLIDE 6

Classification issues Classification issues NEEA NEEA

  • Florida Bay: Highly sensitive system is severely impacted when

chlorophyll a reaches 5 µg L-1, which is considered Low by the NEEA category definition

  • Narraguagus Bay: Naturally occurring nuisance and toxic blooms

which come into the system from the ocean

  • NW coast: HAB events due to upwelling relaxation occurring
  • ffshore, transported into the coastal bays and estuaries

Others Others

  • Similar issues for HAB, e.g. in the Western Iberian Atlantic region
  • r the Benguela upwelling
  • D.O. thresholds set in absolute terms penalize water bodies with a

naturally lower capacity to dissolve O2, due to higher T and S

  • Short residence times or high natural turbidity favour shifts fr

Short residence times or high natural turbidity favour shifts from

  • m

pelagic to benthic symptoms of eutrophication pelagic to benthic symptoms of eutrophication

  • Use of means instead of medians or a percentile based approach

may misclassify systems subject to short extreme events

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Typology reality check Typology reality check (b) ecosystem reality (b) ecosystem reality

Frequency (spatial/temporal variability) Natural conditions A B C A B C Stressors (pressure) Symptom level Threshold A Threshold C

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Dissolved oxygen in the Dissolved oxygen in the Ria Ria Formosa Formosa Channels and Channels and intertidal intertidal areas areas

D.O in the channels D.O in the tide pools

O2 (mg L-1) Julian day No effluent loads (only ocean inputs) 2X standard model (580 ton N y-1)

50 100 150 200 250 300

2 3 4 5 6 7 8 9 10 More

10 20 30 40 50 60 70 80 90 100 Frequency Cumulative % 50 100 150 200 250 300

2 3 4 5 6 7 8 9 10 More

10 20 30 40 50 60 70 80 90 100 Frequency Cumulative % 10 20 30 40 50 60 70 80 90 100

3 4 5 6 7 8 9 10 11 12 13 14 15 More

Dissolved Oxygen (mg l-1)

10 20 30 40 50 60 70 80 90 100

Cumulative %

Frequency Cumulative % 10 20 30 40 50 60 70 80 90 100

3 4 5 6 7 8 9 10 11 12 13 14 15 More

Dissolved Oxygen (mg l-1) Frequency

10 20 30 40 50 60 70 80 90 100 Frequency Cumulative %

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Long Long-

  • term (~70 years) series of phytoplankton

term (~70 years) series of phytoplankton species species

Key Dinoflagellates Chlorophytes Diatoms Other families Prymnesiophytes

  • 140
  • 120
  • 100
  • 80
  • 60
  • 40
  • 20

20 40 60 80

  • 150
  • 100
  • 50

50 100 150 200 A6 A5 A7 A2 A1

  • L. Óbidos

Mondego A3 A4

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Number of phytoplankton species as a Number of phytoplankton species as a function of water residence time function of water residence time

r = 0.93 p < 0.01 50 100 150 200 250 300 350 400 450 500 5 10 15 20 25 Water residence time (days) Number of phytoplankton species Tejo Mondego Sado Minho

  • R. Aveiro

Guadiana y = 14.79x + 122.6 r = 0.93 p < 0.01 50 100 150 200 250 300 350 400 450 500 5 10 15 20 25 Water residence time (days) Number of phytoplankton species Tejo Mondego Sado Minho

  • R. Aveiro

Guadiana

Species data: 1929-1998

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ASSETS ASSETS multitype multitype approach for OEC approach for OEC

Symptom 1 Spatial weighting Temporal weighting OEC Symptom 2 Spatial weighting Temporal weighting

A, B and C are types Symptoms may be qualitatively type- specific Quantitative or semi-quantitative symptom thresholds are type-specific

Symptom level Frequency (spatial/temporal variability) Natural conditions Stressors (pressure) Threshold A A B C Threshold C A B C

Symptom level Frequency (spatial/temporal variability) Natural conditions Stressors (pressure) Threshold A A B C Threshold C A B C

Normalized scores are as before, but related to type-specific thresholds Symptom 1

Symptom 2

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NEEA/ASSETS chlorophyll a and HAB

Frequency distribution according to required Pmax

OEC Chlorophyll a OEC Nuisance and toxic blooms

10 20 30 40 50 60 70 <1.5 1.5-2 2-4 >4 Frequency (% of each Pmax class) 20 40 60 80 100 120 <1.5 1.5-2 2-4 >4 Frequency (% of each Pmax class) Pmax required for phytoplankton to bloom in the estuary NEEA Grade 1 NEEA Grade 2 NEEA Grade 3

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Residence time and species number

Correlation and ranges

Number of species

Mondego Minho Tejo Ria de Aveiro Sado

Nº species = 14.012Tr + 137.78 r = 0.93 (p< 0.025)

50 100 150 200 250 300 350 400 450 5 10 15 20 25

Residence time (days)

Species data: 1929-1998

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Final Final comments comments

  • Natural conditions are widely variable, due to abiotic and bioti

Natural conditions are widely variable, due to abiotic and biotic factors. This puts into c factors. This puts into question the use of absolute thresholds for eutrophication sympt question the use of absolute thresholds for eutrophication symptoms;

  • ms;
  • Eutrophication assessment currently relies on a PSR approach, th

Eutrophication assessment currently relies on a PSR approach, therefore the distinction erefore the distinction between natural and anthropogenic causes is critical, in order t between natural and anthropogenic causes is critical, in order to define responses

  • define responses

(measures); (measures);

  • Natural variability may be translated into types, which will det

Natural variability may be translated into types, which will determine the reference ermine the reference conditions for eutrophication symptoms. Deviations from a type conditions for eutrophication symptoms. Deviations from a type-

  • specific pristine

specific pristine situation will determine response; situation will determine response;

  • Assessment methods such as NEEA and ASSETS do already accommodat

Assessment methods such as NEEA and ASSETS do already accommodate natural e natural variability, by accounting for vulnerability and susceptibility, variability, by accounting for vulnerability and susceptibility, which are indirectly related which are indirectly related to typology (e.g. more vulnerable systems naturally have higher to typology (e.g. more vulnerable systems naturally have higher symptom expression); symptom expression);

  • Type

Type-

  • specific reference conditions may be defined using (a) Pristine

specific reference conditions may be defined using (a) Pristine systems (b) systems (b) Historical data (c) Heuristics (d) Modeling; Historical data (c) Heuristics (d) Modeling;

  • Research models may be used to explore changes in state (impacts

Research models may be used to explore changes in state (impacts) due to various ) due to various pressure scenarios for different types, to help define meaningfu pressure scenarios for different types, to help define meaningful thresholds. l thresholds.