Development of a Phytoplankton Index of Biotic Integrity for

Chesapeake Bay

• Richard V. Lacouture – MSUERC

• Claire Buchanan – ICPRB

• Harold G. Marshall – ODU

• Jacqueline Johnson – ICPRB

• Lots of others

“Biological Integrity”

• Biological Integrity- “the capability of supporting and maintaining a balanced,

integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of the natural (minimally impaired) habitat...”

(Karr and Dudley 1981)

• Index of Biotic Integrity - a set of metrics devised for a specific assemblage of

organisms which describes habitat condition for that assemblage

- serves as an integrative approach to resource or ecosystem management

Steps in the Development of the PIBI

• Data compilation and standardization• Classification of reference and degraded

habitat conditions• Metric selection – power to discriminate• Establish scoring criteria for individual

metrics - thresholds• Aggregate and score multimetric index• Validate the index using independent data

Potential Reference Community

Habitat Classification THE WATER QUALITY BINNING TECHNIQUE

Most Degraded Least Degraded Water Quality Conditions

Water Quality

Conditions

DIN

PO4

SECCHI DEPTH

Habitat Classification - A Look at the Real Data

Reference Condition CriteriaPhytoplankton

• Must Pass All Criteria to Be Reference• Must Fail All Criteria to Be Impaired

Spring Summer

Secchi Depth (meters)

TF >0.9 > 0.8

OH >0.7 > 0.6

MH > 1.8 > 1.45

PH > 2.15 > 1.85

PO4 (mg liter-1)

TF < 0.038 < 0.027

OH < 0.028 < 0.074

MH < 0.011 < 0.007

PH < 0.007 < 0.007

DIN (mg liter-1)

TF < 2.11 < 1.91

OH < 1.77 < 1.22

MH < 0.96 < 0.07

PH < 0.07 < 0.07

Metric Selection

0

1

2

3

4

5

6

7

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

VALUE OF IBI SCORES

FR

EQ

UE

NC

Y

DEGRADED SITES

REFERENCE SITES

ALL DATA

The Ideal Metric

Metric Discrimination

Metric Discrimination

Meets Expectations

Establishing Metric Scoring Thresholds

Parameters Selected for PIBI - SpringMETRIC TF OH MH PH

C:Chl Ratio X X X X

Surface Chlorophyll a X X X X

% Cryptophyte Biomass X

Cyanophyte Biomass X

Diatom Biomass X

Dinoflagellate Biomass X

DOC X X X X

Pheophytin X X X X

P. minimum abundance X X

Total Biomass X X X X

Parameters Selected for PIBI - Summer

METRIC TF OH MH PH

C:Chl Ratio X X

Surface Chlorophyll a X X X X

% Cryptophyte Biomass X

Cyanophyte Biomass X X

Diatom Biomass X X X

Dinoflagellate Biomass X X

DOC X X X X

M. aeruginosa Abundance X

Pheophytin X X X X

Picoplankton Abundance X X

Total Biomass X X

PIBI Scoring Criteria – Spring Polyhaline

METRIC 1 3 5

C:Chl <71.0 71.0 & 107.5

>107.5

Surf. Chl a >4.0 2.8 & 4.0 <2.8

% Crypto Biom >7.1 4.9 & 7.1 <4.9

DOC >2.61 2.50 & 2.61 <2.50

Pheophytin >0.90 0.55 & 0.90 <0.55

P. min. Abund >7,488 672 & 7,488

<672

Total Biomass >1,062 NULL NULL

Discrimination Efficiencies of Individual PIBI Metrics Summer - Percentage of Correct Classifications

TF

Deg

Ref

C:Chl S. Chl a

80.2

76.6

CyanC

62.2

63.6

DiatC

68.4

71.2

DinoC DOC

90.7

91.4

Pheo

72.6

81.3

TotC

68.4

74.2

OH

Deg

Ref

69.0

70.1

63.7

63.9

72.9

75.6

72.0

70.0

71.8

75.9

MH

Deg

Ref

57.9

58.7

76.1

75.2

60.0

64.0

61.7

68.0

71.4

74.6

PH

Deg

Ref

77.4

79.6

59.3

66.7

66.7

61.4

71.9

54.9

64.3

66.7

74.1

73.2

63.2

63.2

Cell chlorophyll content adjusts to

ambient light levels. In turbid waters, cells

have high chlorophyll -biomass ratios which

are indicative of sediment pollution

PROCESS INDICATOR Chlorophyll : Carbon

High concentrations of Prorocentrum minimum cause mortality and minimal growth rates in juvenile oysters. The frequency of these high concentrations (>3,000 cells/ml) increases as chlorophyll levels increase.

SPECIES INDICATOR Prorocentrum minimum

Validation - Classification EfficienciesThis was run on 2003 Monitoring data and 1998-

2002 Pfiesteria Monitoring data

SPRING SUMMER

TF 70.0% TF 78.4%

OH 70.5% OH 75.5%

MH 78.1% MH 77.8%

PH 84.4% PH 79.8%

Application of the P-IBI

• Spatial look at Chesapeake Bay Water Quality Monitoring Program’s phytoplankton sampling stations, 2004

• Temporal look at mainstem Chesapeake Bay stations – spring and summer

• Establishing a Restoration Goal based on the P-IBI

CB5.2LE2.2

RET2.2

TF2.3

TF1.5

TF1.7

LE1.1

CB4.3C

ET5.2 ET5.1

CB3.3C

W T5.1

CB2.2

CB1.1

CB6.2

LE3.6

RET3.1

TF3.1

CB6.4

CB7.3EW E 4.2

RET4.3

TF4.2

CB7.4LE5.5

RET5.2TF5.5

SBE 2

SBE 5

CHESAPEAKE BAY WATERQUALITY MONITORING PROGRAMPHYTOPLANKTON STATIONS

Overall Scoring CriteriaAdd Up, Average and Scale

1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25 3.5 3.75 4 4.25 4.5 4.75 5

Good

Fair-Good

Fair

Fair-Poor

Poor

Goal

Marginal

Degraded

Severely Degraded

Pla

ntkt

on &

Zoo

plan

kton

Ben

thos

PHYTOPLANKTON IBI SPRING 2004

BAD (1 - 2.0)

FAIR-BAD (>2.0 - 2.67)

FAIR (>2.67 - 3.33)

FAIR-GOOD(>3.33-4.0)

GOOD (>4.0 - 5)

1.9

2.4

2.1

2.4

2.5

1.5

3.3

1.6

2.3

2.1

2.2

2.1

2.9

3.8

2.2

3.4

4.6

2.3

2.5

2.9

1.7

2.6

2.32.1

2.73.0

2.7

PHYTOPLANKTON IBI SUMMER 2004

BAD (1- 2.0)

FAIR-BAD (>2.0- 2.67)

FAIR (>2.67- 3.33)

FAIR-GOOD(>3.33- 4.0)

GOOD (>4.0- 5)

2.5

3.5

1.6

2.5

1.1

1.9

3.3

1.9

3.1

3.0

2.4

1.2

1.7

2.0

2.7

2.6

3.0

1.7

3.21.7

2.2

1.2

1.0

2.7

3.8

1.62.3

MEAN SPRING PHYTOPLANKTON IBI SCORES MD MAINSTEM CHESAPEAKE BAY 1985-2004

1

1.5

2

2.5

3

3.5

4

4.5

5

85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04

P-IB

I SCO

RE

CB2.2 CB3.3C CB4.3C CB5.2

MEAN SPRING PHYTOPLANKTON IBI SCORES VA MAINSTEM CHESAPEAKE BAY 1985-2004

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04

P-IB

I SC

OR

E

CB6.1 CB6.4 CB7.3E CB7.4

MEAN SUMMER PHYTOPLANKTON IBI SCORES MD MAINSTEM CHESAPEAKE BAY 1985-2004

1

1.5

2

2.5

3

3.5

4

4.5

5

85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04

P-IB

I SCO

RE

CB2.2 CB3.3C CB4.3C CB5.2

MEAN SUMMER PHYTOPLANKTON IBI SCORES VA MAINSTEM CHESAPEAKE BAY 1985-2004

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04

P-IB

I SCO

RE

CB6.1 CB6.4 CB7.3E CB7.4

MEAN SPRING PHYTOPLANKTON IBI SCORES POTOMAC RIVER 1985-2004

1

1.5

2

2.5

3

3.5

4

4.5

5

85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04

P-IB

I SCO

RE

LE2.2 RET2.2 TF2.3

MEAN SUMMER PHYTOPLANKTON IBI SCORES POTOMAC RIVER 1985-2004

1

1.5

2

2.5

3

3.5

4

4.5

5

85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04

P-IB

I SCO

RE

LE2.2 RET2.2 TF2.3

Establishing a P-IBI Goal Relative to Chlorophyll a Criteria

P-IBI > 4.0 - typically associated with chlorophyll a levels lower than those in P-IBI > 3.0 (*, p<0.05; **, p<0.01)

- median levels overlap model-simulated mean chlorophyll a levels that support attainment of all Chesapeake dissolved oxygen criteria

Establishing a P-IBI Goal Relative to Water Clarity Criteria

PIBI > 4.0 - typically associated with Secchi depths greater than those in PIBI > 3.0 (*, p<0.05; **, p<0.01)

- more closely overlaps Secchi depths habitat requirements of SAV and attainment of Chesapeake Bay water clarity criteria

Establishing a P-IBI Goal Relative to Dissolved Oxygen Criteria

PIBI > 4.0 and PIBI > 3.0- no significant differences in above-pycnocline (AP) waters & spawning/nursery areas; both meeting

DO criteria in these areas- low tails of DO distributions in PIBI > 4.0 are slightly higher (better) than those for PIBI > 3.0.

Future Directions for the Phytoplankton Monitoring Programs

• Continue to refine and lobby for using P-IBI as a viable indicator of habitat quality by state and Federal managers of Chesapeake Bay

• Ultimately, use the P-IBI results in an Ecosystem Index of Biotic Integrity

• Document taxonomic changes in the phytoplankton populations of Chesapeake Bay relative to changing water quality conditions, introduced taxa, etc. and the impact that these shifts may have on higher trophic levels

• Continue to serve as a sentinel for HAB species and to maintain a historical record of bloom events in Chesapeake Bay