OMSAP Public Meeting September 1999 Water Quality Monitoring Program and Baseline Results OMSAP...

OMSAP Public MeetingSeptember 1999

Water Quality Monitoring Program and Baseline Results

OMSAP Technical MeetingSeptember 22, 1999

Carlton D. Hunt & P. Scott LibbyBattelleDuxbury OperationsDuxbury, MA 02332


Acknowledgements

Numerous scientists, regulators, and citizens from the New England area have contributed to the design, implementation, interpretation and understanding of water quality in the Massachusetts Bay system• Siting studies• Research• Monitoring

Products of this work are included in over 20 major water quality reports available from MWRA at http://www.mwra.state.ma.us/harbor/enquad/trlist.htm and numerous peer reviewed publications

InflowOutflow

Light

ConcernsEcologicalEcological NutrientsNutrients Contaminants Organic MaterialOrganic Material Food ChainFood Chain Community StructureCommunity Structure Living ResourcesLiving Resources

Human Health Contaminants Bacteria Viruses Bioaccumulation

SEDIMENT

Mammals

Infauna

Piscivorous Fish

ZooplanktonZooplankton

PhytoplanktonPhytoplankton

Planktivorous Fish

Epibenthos

Demersal Fish

Regeneration

DetritusParticulateParticulate

MicrobesMicrobes

DissolvedDissolved

WATER COLUMN

Sources Rivers BoundaryBoundary Nonpoint EffluentsEffluents

Gas ExchangeExchangeN2, | O2, CO2

ATMOSPHERE

N, P, Si, ON, P, Si, O22, CO, CO22 Microbes


Presentation Summary

Overview Water Quality Monitoring Program Major Baseline Characteristics Spatial and Temporal Responses

• Nutrients• Chlorophyll• Dissolved Oxygen• Plankton

Thresholds Future expectations


Nutrients, dissolved oxygen, or phytoplankton biomass

Phytoplankton and zooplankton community composition in the nearfield and farfield occur

Phytoplankton production rates in the water column near the outfall and outer Boston Harbor

Water Quality Monitoring Introduction

WQ monitoring program objectives are to determine if changes occur in the nearfield (local) or farfield (regional) to


Water Quality Monitoring Overview

Nutrients, chlorophyll, and dissolved oxygen Harbor signatures and gradients in Mass Bay Plankton communities Thresholds and detection of change Expectations of conditions after the outfall begins

discharging at the Massachusetts Bay location

This presentation focuses on spatial and temporal responses in the following areas


MWRA Monitors 21 Nearfield and 28 Farfield Water Quality Stations in Massachusetts Bay

Water Quality Measurement Program


Water Quality Monitoring Vertical profiles

Continuous vertical hydrographic profiles to within 5 m of the bottom• Temperature• Salinity• Dissolved oxygen• Chlorophyll fluorescence• Beam attenuation (particles)• Irradiance (light)

Discrete samples from 3 or 5 depths (depending on water depth)


Water Quality Monitoring Parameters Measured

Station Type Code1Subsample AnalysisA D E F G R P Z

SampleDepth Class2

Dissolved Inorganic Nutrients A, B, C, D, EDissolved Organic CarbonTotal Dissolved NitrogenTotal Dissolved PhosphorousParticulate Organic CarbonParticulate Organic NitrogenParticulate PhosphorousBiogenic Silica

A, C, E

Urea A, C A, B, C, D, EChlorophyll a and Phaeophytin a

A, C, ETotal Suspended Solids A, C, E

A, B, C, D, EDissolved Oxygen A, C, E

1Defined by Suite of Analyses.2Sample Depth Classes.

A Surface (<3 meters) D Mid-bottomB Mid-surface E Bottom (within 5 m of bottom)C Mid-depth (chlorophyll a maximum) Z Upper 30 m tow through water column


Water Quality Monitoring Parameters Measured

Biological Parameters Sampled by Station Type and Sample Depth

Station TypeCode1

Subsample Analysis

D G R P ZSample

Depth Class2

Zooplankton ZPhytoplankton (whole water) A, CPhytoplankton (screened water) A, CRespiration A, C, EPrimary Productivity A, B, C, D, E

1Defined by Suite of Analyses.2Sample Depth Classes.

A Surface (<3 meters) D Mid-bottomB Mid-surface E Bottom (within 5 m of bottom)C Mid-depth (chlorophyll a maximum) Z Upper 30 m tow through water column


Water Quality Monitoring Data evaluation

To understand spatial and temporal trends and causal relationships

Hydrographic Response to weather (wind and rain) Light fields

PhytoplanktonChlorophyll biomass Species composition Nuisance species

Nutrients Plankton responsesPrimary production

Zooplankton Species composition

Dissolved Oxygen Production /Respiration


Water Quality Baseline Characteristics

Gradients (nutrients, biomass, and dissolved oxygen)• Temporal • Offshore • Vertical

Tidal exchange and export from Boston Harbor

Plankton Communities• Phytoplankton• Zooplankton


Water Quality Gradients

Gradients in the system are examined using• horizontal contours • vertical sections • temporal plots

– individual stations – regions in the Bay

F01

F02

F03

F05

F06

F07

F10

F12

F13

F14 F15

F16F17

F18

F19

F22

F23

F24

F25

F26

F27

F28

F29

F30

F31

F32

F33

N01 N02 N03 N04

N05

N06

N07N08N09N10

N11

N12N13N14N15

N16

N17N18N19

N20N21

BO

UN

DA

RY

MA

RSH

FIE

LD

COHASSET

BOSTON

- NEARFIE

LD

MA

RSH

FIELD

NEA

RFIELD -

NEA

RFI

ELD

42°0

0'

42°00'

42°1

5'

42°15'

42°3

0'

42°30'

71°00'

71°00'

70°45'

70°45'

70°30'

70°30'

70°15'

70°15'

0 5 10 15 Kilometers

F01 Sampling Location Name

Outfall Diffuser

Stellwagen Bank National Marine Sanctuary

LEGEND

N


Water Quality Horizontal Gradients

The gradient offshore of Boston Harbor and along the shore from the Harbor to Plymouth is a persistent feature in the surface waters under the present discharge regime.

0.75

3.68

4.46

4.665.35

5.405.53

5.87

6.056.24

6.27

6.27

6.34

6.41

6.62

6.79

6.856.88

6.88

7.13

7.36

7.49

7.66

7.68

7.82

8.05

8.22

8.31

8.62

8.87

9.06

9.64

9.80

11.29

11.94

14.01

14.85

15.3216.17

21.38

23.45

28.37

1 3 5 7 9 11 13 15 30

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: N o3+no2+nh4Sam pling D epth: SurfaceLast Survey D ay: 2 /2 /99Sam pling Event: W F991M in im um Value 0.75 µM at F02M axim um Value 28.37 µM at F23C ontour In terval =2 µM


Water Quality Temporal ResponsesNitrate

Station N01

0

2

4

6

8

10

12

14

Jan Apr Jul Oct Dec

NO

3(µM

)

Station N04

0

2

4

6

8

10

12

14

Jan Apr Jul Oct Dec

NO

3(µM

)

Station N21

0

2

4

68

10

12

14

Jan Apr Jul Oct Jan

NO

3(µM

)

Bottom Surface

Station N10

0

2

4

6

8

10

12

14

Jan Apr Jul Oct Jan

NO

3(µM

)

N01N02

N03N04

N05

N06

N07N08

N09N10

N11

N12

N13N14

N15

N16

N17N18

N19

N20

N21

USGS

42°1

6'

42°16'

42°2

0'

42°20'

42°2

4'

42°24'

42°2

8'

42°28'

42°3

2'

42°32'

71°00'

71°00'

70°56'

70°56'

70°52'

70°52'

70°48'

70°48'

70°44'

70°44'

USGS Mooring

0 2 4 6 8 Kilometers

LEGEND

N01 Sampling Location Name

Outfall Diffuser

N

Station N07

0

2

4

6

8

10

12

14

Jan Apr Jul Oct JanN

O3(

µM)


N01N02

N03N04

N05

N06

N07N08

N09N10

N11

N12

N13N14

N15

N16

N17N18

N19

N20

N21

USGS

42°1

6'

42°16'

42°2

0'

42°20'

42°2

4'

42°24'

42°2

8'

42°28'

42°3

2'

42°32'

71°00'

71°00'

70°56'

70°56'

70°52'

70°52'

70°48'

70°48'

70°44'

70°44'

USGS Mooring

0 2 4 6 8 Kilometers

LEGEND

N01 Sampling Location Name

Outfall Diffuser

N

Water Quality Temporal ResponsesSilicate

Station N01

0

5

10

15

Jan Apr Jul Oct Dec

SiO

4(µM

)

Station N21

0

5

10

15

Jan Apr Jul Oct Jan

SiO

4(µM

)

Bottom Surface

Station N10

0

5

10

15

Jan Apr Jul Oct Jan

SiO

4(µM

)

Station N07

0

5

10

15

Jan Apr Jul Oct Jan

SiO

4(µM

)

Station N04

0

5

10

15

Jan Apr Jul Oct Dec

SiO

4(µM

)


Water Quality Horizontal GradientsSurface Salinity

30.76

30.4530.7630.78

30.7230.64

30.77

30.8130.76

30.57

30.5630.65

30.58

30.7930.63

30.58

30.76

30.78

30.76

30.71

30.9930.77

30.78

30.75

30.66

30.68

30.55

30.4830.48

30.49

30.77

30.7430.74

29.14

30.53

30.70

30.8530.85

31.86

30.7030.68

30.67

30.55

30.72

30.68

30.56

30.96

30.73

30.42

31.10

2 3 2 4 2 5 2 6 2 7 2 8 2 9 3 0 3 3

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: Salin itySam pling D epth: SurfaceLast Survey D ay: 8 /25/98Sam pling Event: W F98BM in im um Value 29.14 PSU at F23M axim um Value 31.86 PSU at F19C ontour In terval =1 PSU

30.7630.68

31.46 31.82

31.61

31.38

32.27

31.58

31.85

31.85

31.41

31.04

31.65

31.74

30.42

31.82

31.86

32.01

31.70

31.67

32.08

30.35

31.67

30.82

29.38

31.32

31.63 31.98

31.85

30.25

32.08

31.69

31.08

32.02

31.80

31.4831.63

32.09

31.58

31.7231.82

2 3 2 4 2 5 2 6 2 7 2 8 2 9 3 0 3 3

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: Salin itySam pling D epth: SurfaceLast Survey D ay: 2 /2 /99Sam pling Event: W F991M in im um Value 29.38 PSU at F30M axim um Value 32.27 PSU at F27C ontour In terval =1 PSU


Water Quality Horizontal GradientsJune 1998 Storm Response Surface Salinity

30.34

30.21

27.28

30.03

30.44

29.7729.52

29.93

30.56

29.09

28.96

30.11

27.00

30.01

27.80

25.5127.96

25.48

25.4225.1425.66

28.9925.27

29.70

29.00

30.1830.37

30.36

26.19

30.21

22.73

28.2026.93

27.03

26.31

27.60

24.9124.99

27.3324.97

30.36

29.80

2 3 2 4 2 5 2 6 2 7 2 8 2 9 3 0 3 3

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: Salin itySam pling D epth: SurfaceLast Survey D ay: 6 /22/98Sam pling Event: W F987M in im um Value 22.73 PSU at F30M axim um Value 30.56 PSU at F05C ontour In terval =1 PSU


Water Quality Horizontal GradientsSurface Temperature

14.07

14.1416.5017.59

15.9215.23

16.89

15.0917.43

14.41

14.3016.04

16.43

17.5214.79

14.46

16.70

17.40

17.83

17.31

13.6115.88

16.78

16.20

17.78

15.63

13.72

13.5313.53

14.95

15.94

15.5415.54

15.39

11.79

15.62

15.0315.03

15.65

14.7915.78

16.07

16.31

16.20

16.71

15.69

11.16

14.25

15.21

18.30

3 5 7 9 11 13 15 17 21

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: Tem peratureSam pling D epth: SurfaceLast Survey D ay: 8 /25/98Sam pling Event: W F98BM in im um Value 11.16 C at F05M axim um Value 18.30 C at F02C ontour In terval =2 C

2.64

2.74

2.91

2.91

2.94

3.03

3.05

3.05

3.08

3.11

3.13

3.183.193.21

3.24

3.24

3.26

3.31

3.323.37

3.39

3.43

3.473.52

3.55

3.60

3.60

3.60

3.61

3.623.63

3.65

3.66

3.74

3.86

3.87

3.88

3.99

4.14

4.20

4.23

4.23

3 5 7 9 11 13 15 17 21

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: Tem peratureSam pling D epth: SurfaceLast Survey D ay: 2 /2 /99Sam pling Event: W F991M in im um Value 2.64 C at F23M axim um Value 4.23 C at F12C ontour In terval =2 C


Water Quality Horizontal GradientsSurface DIN

11.93 9.63

5.16

6.82

1.76

9.54

4.66

7.80

3.45

2.64

1.16

0.50

6.38

0.40

0.25

2.13

0.43

2.04

1.40

2.06

0.29

0.710.99

1.44

1.64

1.14

1.57

2.05

2.25

0.63

3.07

0.99

0.62

0.36

0.62

1.00

0.90

0.39

0.64

0.31

1.45

1.60

0.69

0.58

0.44

1.67

2.56

1 3 5 7 9 11 13 15 19

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: N o3+no2+nh4Sam pling D epth: SurfaceLast Survey D ay: 8 /18/98Sam pling Event: W F98BM in im um Value 0.26 µM at F14M axim um Value 11.93 µM at F30C ontour In terval =2 µM

0.75

3.68

4.46

4.665.35

5.405.53

5.87

6.056.24

6.27

6.27

6.34

6.41

6.62

6.79

6.856.88

6.88

7.13

7.36

7.49

7.66

7.68

7.82

8.05

8.22

8.31

8.62

8.87

9.06

9.64

9.80

11.29

11.94

14.01

14.85

15.3216.17

21.38

23.45

28.37

1 3 5 7 9 11 13 15 30

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: N o3+no2+nh4Sam pling D epth: SurfaceLast Survey D ay: 2 /2 /99Sam pling Event: W F991M in im um Value 0.75 µM at F02M axim um Value 28.37 µM at F23C ontour In terval =2 µM


Water Quality Horizontal GradientsSurface Silicate

1.15

2.08

2.24

2.372.42

2.93

3.26

3.27

3.33

3.36

3.40

3.49

3.673.73

3.76

3.97

4.00

4.04

4.09 4.134.45

4.76

5.16

5.335.36

5.50

5.85

5.97

6.28

6.31

6.62

6.85

6.89

7.24

8.09

8.29

8.64 8.71

8.81

10.68

13.86 15.81

1 3 5 7 9 11 13 18

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: S ilicateSam pling D epth: SurfaceLast Survey D ay: 2 /2 /99Sam pling Event: W F991M in im um Value 1.15 µM at F02M axim um Value 15.81 µM at F23C ontour In terval =2 µM

0.54

0.571.27

0.01

5.980.43

1.35

0.89

2.85

1.29

2.57

5.41

3.211.15

2.51

1.80

0.26

0.85

3.00

4.85

0.32

1.21

0.200.480.48

1.29

0.25

3.250.15

0.40

0.24

0.90

9.03

0.300.30

0.44

0.80

2.76

1.541.40

4.883.773.77

5.10

1.12

3.57

0.14

0.80

0.72

0.16

1 3 5 7 9 11 13 17

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: S ilicateSam pling D epth: SurfaceLast Survey D ay: 8 /18/98Sam pling Event: W F98BM in im um Value 0.01 µM at N 03M axim um Value 9.03 µM at F30C ontour In terval =2 µM


Water Quality Horizontal GradientsSurface Chlorophyll

0.55

7.50 0.59

1.7711.79

1.000.09

13.03

6.404.24

1.27

1.0810.56

11.99

0.03

0.25

0.41

3.781.04

0.20

0.09

2.60

7.54

3.81

5.955.95

0.54

0.670.67

5.10

9.00

0.19

2.232.23

0.34

4.660.05

0.14

1.86

2.27

0.46

0.83

5.63

3.15

1.58

0.66

1 3 5 7 9 11 15

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: F luorescenceSam pling D epth: SurfaceLast Survey D ay: 8 /25/98Sam pling Event: W F98BM in im um Value 0.03 µg/L at N 04M axim um Value 13.03 µg/L at N 11C ontour In terval =2 µg/L

0.02

0.11

0.25

0.88

0.91

1.051.10

1.66

1.88

2.79

2.94 3.11

3.20

3.293.64

4.054.27

4.39

4.55

4.61

4.62

4.76

4.79

5.24

5.245.26

5.81

6.48

7.06

8.35

13.46

1 3 5 7 9 11 15

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: F luorescenceSam pling D epth: SurfaceLast Survey D ay: 2 /2 /99Sam pling Event: W F991M in im um Value 0.02 µg/L at F13M axim um Value 13.46 µg/L at F27C ontour In terval =2 µg/L


Water Quality Horizontal GradientsBottom Dissolved Oxygen

9.56

10.199.51

9.59

8.2110.22

9.31

8.48

8.999.29

9.19

8.43

9.449.44

9.30

10.06

8.55

10.83

9.19

9.34

7.95

9.76

8.61

9.04

8.15

9.43

8.90

8.35

8.57

9.47

8.41

8.01

8.279.27

9.93

10.1710.17

9.31

7.29

9.309.519.51

8.228.81

9.77

8.31

8.44

8.45

10.378.81

5 6 7 8 9 10 11 12 13

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: In S itu D issolved O xygenSam pling D epth: BottomLast Survey D ay: 8 /18/98Sam pling Event: W F98BM in im um Value 7.29 m g/L at F02M axim um Value 10.83 m g/L at F03C ontour In terval =1 m g/L

9.32

9.329.37

9.479.49

9.57

9.77

9.78

9.81

9.839.95

9.9510.07 10.09

10.18

10.30

10.41

10.4510.60

10.80

10.81

10.81

10.82

10.86

10.91

10.95

10.95

10.96

11.02

11.03

11.05

11.06

11.13

11.14

11.1511.15

11.20

11.23

11.3011.31

12.05

5 6 7 8 9 10 11 12 13

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: In S itu D issolved O xygenSam pling D epth: BottomLast Survey D ay: 2 /2 /99Sam pling Event: W F991M in im um Value 9.32 m g/L at N 07M axim um Value 12.05 m g/L at N 10C ontour In terval =1 m g/L


Water Quality Horizontal GradientsSurface Ammonia

0.24

0.33

0.36

0.42

0.430.44

0.44

0.48

0.48

0.49

0.49 0.490.51

0.51

0.54

0.560.57

0.60

0.61

0.63

0.660.71

0.780.81

0.81

0.83

0.85

0.86

1.10

1.36

1.92

2.34

2.38

3.04

3.13

4.37

5.35

5.576.75

10.00

11.68

14.31

1 3 5 7 9 16

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: Am m oniumSam pling D epth: SurfaceLast Survey D ay: 2 /2 /99Sam pling Event: W F991M in im um Value 0.24 µM at N 08M axim um Value 14.31 µM at F23C ontour In terval =2 µM

0.21

1.440.41

1.32

6.950.20

0.80

0.38

0.85

1.48

0.99

1.23

0.450.24

0.69

0.83

0.19

0.49

0.53

4.66

0.29

1.30

0.990.720.72

0.22

0.34

6.230.98

0.18

0.51

1.53

7.63

0.310.31

0.38

0.69

4.66

2.290.71

2.922.692.69

0.60

1.08

1.94

0.36

1.15

0.14

0.60

1 3 5 7 9 12

71° 00' W 70° 50' W 70° 40' W 70° 30' W 70° 20' W 70° 10' W

41° 50' N

42° 00' N

42° 10' N

42° 20' N

42° 30' N

42° 40' N

0 5 10 15 20

kilom eters

Param eter: Am m oniumSam pling D epth: SurfaceLast Survey D ay: 8 /18/98Sam pling Event: W F98BM in im um Value 0.14 µM at N 19M axim um Value 7.63 µM at F30C ontour In terval =2 µM


Water Quality Harbor Gradient after Secondary Treatment - NH4

(a) Ammonium North Harbor

0

5

10

15

20

25

30

Jan-95 Jul-95 Jan-96 Jul-96 Jan-97 Jul-97 Jan-98 Jul-98 Jan-99

NH

4 (

M)

Station 142

Station F23


Water Quality Harbor Gradient after secondary treatment - NH4

(b) Ammonium South Harbor

0

5

10

15

20

25

30

Jan-95 Jul-95 Jan-96 Jul-96 Jan-97 Jul-97 Jan-98 Jul-98 Jan-99

NH

4 (

M)

Station 141

Station F31


Water Quality Vertical Gradients Boston to GOM Transect - Salinity

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

2 1 2 3 2 5 2 7 2 9 3 1 3 5

Param eter: Salin ityLast Survey D ay: 8 /18/98Sam pling Event: W F98BBoston-N earfie ld T ransectC ontour In terva l =2 PSU

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

2 1 2 3 2 5 2 7 2 9 3 1 3 5

Param eter: Salin ityLast Survey D ay: 2 /27/98Sam pling Event: W F982Boston-N earfie ld T ransectC ontour In terva l =2 PSU


Water Quality Vertical Gradients Boston to GOM Transect - Temperature

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

3 5 7 9 11 13 15 21

Param eter: Tem peratureLast Survey D ay: 8 /25/98Sam pling Event: W F98BBoston-N earfie ld T ransectC ontour In terva l =2 C

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

3 5 7 9 11 13 15 19

Param eter: Tem peratureLast Survey D ay: 2 /27/98Sam pling Event: W F982Boston-N earfie ld T ransectC ontour In terva l =2 C


Water Quality Vertical Gradients Boston to GOM Transect - DIN

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

1 3 5 7 9 11 13 19

Param eter: N o3+no2+nh4Last Survey D ay: 2/27/98Sam pling Event: W F982Boston-N earfie ld T ransectC ontour In terval =2 µM

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

1 3 5 7 9 11 13 26

Param eter: N o3+no2+nh4Last Survey D ay: 8 /18/98Sam pling Event: W F98BBoston-N earfie ld T ransectC ontour In terva l =2 µM


Water Quality Vertical Gradients Boston to GOM Transect - Silicate

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

1 3 5 7 9 11 13 25

Param eter: S ilicateLast Survey D ay: 2 /27/98Sam pling Event: W F982Boston-N earfie ld T ransectC ontour In terva l =2 µM

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

1 3 5 7 9 11 13 19

Param eter: S ilicateLast Survey D ay: 8 /18/98Sam pling Event: W F98BBoston-N earfie ld T ransectC ontour In terva l =2 µM


Water Quality Vertical GradientsBoston to GOM Transect - Chlorophyll

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

1 3 5 7 9 11 13 17

Param eter: F luorescenceLast Survey D ay: 2 /27/98Sam pling Event: W F982Boston-N earfie ld T ransectC ontour In terva l =2 µg/L

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

1 3 5 7 9 11 13 20

Param eter: F luorescenceLast Survey D ay: 8 /18/98Sam pling Event: W F98BBoston-N earfie ld T ransectC ontour In terva l =2 µg/L


Water Quality Vertical Gradients Boston to GOM Transect - Dissolved Oxygen

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

5 6 7 8 9 10 11 12 14

Param eter: In S itu D issolved O xygenLast Survey D ay: 2 /27/98Sam pling Event: W F982Boston-N earfie ld T ransectC ontour In terva l =1 m g/L

0 10 20 30 40 50

D istance (km )

-100

-80

-60

-40

-20

0

Dep

th (

m)

F23 F24 N 20 N 21 N 16 F19 F27

5 6 7 8 9 10 11 12 14

Param eter: In S itu D issolved O xygenLast Survey D ay: 8 /18/98Sam pling Event: W F98BBoston-N earfie ld T ransectC ontour In terva l =1 m g/L


Water Quality Summary Vertical & Horizontal Gradients

Water column is well mixed over the winter Increasing temperature and runoff in early

spring initiates stratification Spring/summer temperature differences

intensify stratification Stratification remains until fall overturn (due to

lower vertical temp gradient and increased storm activity)

Return to winter conditions in early winter


Water Quality Summary Vertical &Horizontal Gradients

Boston Harbor is localized source of nutrients• Sewage effluent comprises 90% of the land source

nutrients added to Boston Harbor (Kelly 1997) Strong inshore/offshore nutrient gradient away

from Harbor in surface waters Gradients are less distinct in the bottom waters Seasonal nutrients cycle (stratification) Upwelling and winds may be a factor in bringing

nutrients to surface waters in the summer


Water Quality Harbor/Nearfield Exchange

A strong physical front is evident off the mouth of Boston Harbor

Front analysis



outfall

outfall


Water Quality Harbor/Nearfield Exchange From Kelly 1997

0.6 - 0.8 N2

6.6 TN(4.5 DIN)

0.2 TN 1.7 DIN

23-25 TN(11-12 DIN)

~15 TN(5.2-6.6 DIN)

<0.6 - 0.8 N2

0.8 TN

<0.2 TN <1.7 DIN

12-16 TN(2.5-3.9 DIN)

Baseline Period Post-Discharge Period

85% of the nutrients from the Deer Island outfall are currently exported into Massachusetts Bay

100% of the nutrients from the Deer Island outfall will be exported into Massachusetts Bay in the future

Units are in 105 kmols/yr

Freshwater

Ocean exchange

Ocean exchange dominates the nutrients mass balance in Boston Harbor


Water Quality Summary Harbor Exchange

Effluent from Deer Island outfall presently enters Massachusetts Bay

Exchange of Boston Harbor waters with nearfield and coastal waters results in a plume of Harbor water extending southward along the coast in western Massachusetts Bay

Harbor plume is primarily in the western nearfield surface waters and coastal waters to the south


Water Quality Regional Responses

Stations in six regions are examined for temporal and spatial responses• Boston Harbor • Coastal • Nearfield • Cape Cod Bay• Boundary with Gulf of Maine• Offshore (south and east of the

nearfield)

F01

F02

F03

F05

F06

F07

F10

F12

F13

F14F15

F16F17

F18

F19

F22

F23

F24

F25

F26

F27

F28

F29

F30

F31

F32

F33

N16

Harbor

Cape Cod Bay

Offshore

Boundary

Coastal

42°0

0'

42°00'

42°1

5'

42°15'

42°3

0'

42°30'

71°00'

71°00'

70°45'

70°45'

70°30'

70°30'

70°15'

70°15'

0 5 10 15 Kilometers

F01 Sampling Location Name

Outfall Diffuser

Stellwagen Bank National Marine Sanctuary

LEGEND

N


Water Quality Chlorophyll

An indicator of phytoplankton biomass Key measurement and indicator in the water quality program

Temporal and regional distribution are variable Responds to light and nutrient fields (see Keller et al. Poster)

• Summer surface water nutrient limitation• Winter light limitation • Influenced by weather and storm events

Results in a generally consistent seasonal progression

Maximum values are in the pycnocline during stratification and in the waters of the western nearfield and outer Boston Harbor


Water Quality Chlorophyll Distribution

Seasonal peaks are observed in the spring, summer, and fall Classic winter/spring bloom does not always occur Frequently observe a major fall boom Large sustained bloom occurred in the winter/spring of 1999 following a

late winter bloom in December 1998

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

1992 1993 1994 1995 1996 1997 1998 1999 2000

Ch

loro

ph

yll

(g

/L)

Asterionellopsis glacialis

Phaeocystis pouchetii

Phaeocystis pouchetii


Water Quality Nearfield Chlorophyll - Fall Blooms

1995

0

2

4

6

8

10

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecCh

loro

ph

yll

(g

/L)

1998

0

2

4

6

8

10


loro

ph

yll

(g

/L)

1993

0

2

4

6

8

10


loro

ph

yll

(g

/L)


Water Quality Nearfield Chlorophyll - Spring Blooms

0

2

4

6

8

10


loro

ph

yll

(g

/L)

1992

0

2

4

6

8

10


loro

ph

yll

(g

/L)

1994

0

2

4

6

8

10


loro

ph

yll

(g

/L)

1996


Water Quality Nearfield Chlorophyll Winter Bloom 1998-1999

Nearfield Chlorophyll 1998 - 1999

0

2

4

6

8

10

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr MayCh

loro

ph

yll

(g

/L)

Satellite imagery suggests chlorophyll levels in the surface waters of Massachusetts

Bay remained elevated between mid-Dec 1998 and early February 1999


Water Quality Annual Chlorophyll Data

COMPARISON OF ANNUAL MEAN CHLORPHYLL DATAYear Mean

mg/LSTDmg/L

n Detectablechange mg/L

1992 2.02 1.65 1,203 0.271993 2.28 2.91 1,669 0.731994 1.94 1.49 1,658 0.191995 1.43 2.34 1,358 0.521996 1.54 1.90 1,247 0.361997 1.06 1.64 1.262 0.271998 1.81 2.69 1,396 0.681999 In progress

Baseline mean1992-1998

1.73 0.41 7 0.23

Thresholds1992-1998

Caution (1.5 times baseline mean) = 2.60 mg/LWarning (2.0 times baseline mean) = 3.45 mg/L


Water Quality Seasonal Chlorophyll Data

COMPARISON OF SEASONAL CHLORPHYLL DATA 1992-1998Season 95th Percentile

mg/Ln Detectable change

mg/LWinter Spring(January - April)

4.76 2,842 0.16

Summer(May -August)

4.50 4,110 0.19

Fall(September - December)

8.95 2,931 0.56

1999 To be added to the estimate of the 95th percentileThresholds Caution = 95th percentile by season


Water Quality Chlorophyll Summary

Spring bloom not as consistent as conventional wisdom would suggest

Fall bloom appears to be a consistent event having occurred in 5 of 7 years Elevated summer concentrations observed

in Nearfield (98 & 99)


Water Quality Dissolved Oxygen

Degradation of particulate organic matter (POM)• water column• deposited POM in sediments

Other factors• duration and strength of stratification• bottom water temperature• initial DO concentration at onset stratification• downwelling/intrusion events

Many factors affect dissolved oxygen levels in the water


Water Quality Dissolved Oxygen

Mean DO in bottom waters has exceeded the caution level once

1999 may have an exceedance in September or October

5

6

7

8

9

10

11

12

13

1992 1993 1994 1995 1996 1997 1998 1999 2000

DO

(m

g/L

)


Water Quality Nearfield Bottom Water DO Distribution September 8,1999

Nearfield DO Thresholds (as a survey mean)• Caution = 6.5 mg/L• Warning = 6.0 mg/L

Survey Mean• 6.66 mg/L

Western Nearfield DO <6.0 mg/L

Eastern Nearfield DO >7.0 mg/L

6.81

7 .11

6.46

6.13

7.48

5.97

7.15

6.83

7.22

5 .94

6 .02

6.24

7 .58

6 .52

5.59

6 .43

7.53

5.99

7.45

6.83

5.7 6.0 6.3 6.6 6.9 7.2 7.5 7.8 7.9

70° 52' W 70° 50' W 70° 48' W 70° 46' W 70° 44' W 70° 42' W

42° 20' N

42° 22' N

42° 24' N

42° 26' N

0 1 2 3 4

kilom eters

Param eter: In S itu D isso lved O xygenSam pling D epth: BottomLast Survey D ay: 9 /8 /99Sam pling Event: W N 99CM inim um Value 5.59 m g/L at N 11M axim um Value 7.58 m g/L at N 06C ontour In terva l =0.3 m g/L


Water Quality Nearfield Surface and Bottom Water DO Distribution September 8,1999

Surface DO shows a maximum in the western nearfield Note contour interval change from the bottom DO image in the

pervious slide to place both images on the same color scale

9.14

11.22

9 .27

9.11

10.88

9.63

9 .718.91

12.17

9 .95

9 .33

8.93

8.94

9.53

10.11

10.55

9.13

10.83

7.76

12.3312.32

5 6 7 8 9 10 11 12 13

70° 52' W 70° 50' W 70° 48' W 70° 46' W 70° 44' W 70° 42' W

42° 20' N

42° 22' N

42° 24' N

42° 26' N

0 1 2 3 4

kilom eters

Param eter: In S itu D issolved O xygenSam pling D epth: SurfaceLast Survey D ay: 9 /8/99Sam pling Event: W N 99CM inim um Value 7.76 m g/L at N 10M axim um Value 12.33 m g/L at N 19C ontour In terva l =1 m g/L

Surface

6.81

7 .11

6.46

6.13

7.48

5.97

7.15

6.83

7.22

5 .94

6 .02

6.24

7 .58

6 .52

5.59

6 .43

7.53

5.99

7.45

6.83

5 6 7 8 9 10 11 12 13

70° 52' W 70° 50' W 70° 48' W 70° 46' W 70° 44' W 70° 42' W

42° 20' N

42° 22' N

42° 24' N

42° 26' N

0 1 2 3 4

kilom eters

Param eter: In S itu D issolved O xygenSam pling D epth: BottomLast Survey D ay: 9 /8/99Sam pling Event: W N 99CM inim um Value 5.59 m g/L at N 11M axim um Value 7.58 m g/L at N 06C ontour In terva l =1 m g/L

Bottom


Water Quality Seasonal DO Decline Nearfield

5

6

7

8

9

10

11

12

Jun Jul Aug Sep Oct Nov

Dis

solv

ed O

xyge

n (m

g/L

)

1992

1993

1994

1995

1996

1997

1998

Linear(1998)Linear(1997)Linear(1996)Linear(1995)Linear(1994)Linear(1992)Linear(1993)

1992

1993

1995

1994

199619971998

Year Slope Intercept* R2

(mg/L/day) (mg/L)

1992 -0.024 11.0 0.808

1993 -0.025 11.1 0.885

1994 -0.031 10.1 0.929

1995 -0.027 9.9 0.932

1996 -0.025 10.3 0.978

1997 -0.020 9.8 0.632

1998 -0.032 11.5 0.938* Predicted DO on June 1st based on:

DO = Slope * Date + Intercept

The rate of decline in the near bottom water DO is relatively constant in the Nearfield


Water Quality Seasonal DO Decline Stellwagen Basin

6

7

8

9

10

11

12

Jun Jul Aug Sep Oct

Dis

solv

ed O

xyge

n (m

g/L

)

1992

1993

1994

1995

1996

1997

1998

Linear(1998)Linear(1996)Linear(1997)Linear(1995)

1

1

1

1

The rate of decline in the near bottom DO in Stellwagen Basin during stratification is also relatively constant

Year Slope Intercept*

(mg/L/day) (mg/L)

1992 -0.023 10.7

1993 -0.023 10.9

1994 -0.021 9.6

1995 -0.017 8.9

1996 -0.014 9.4

1997 -0.012 9.0

1998 -0.028 11.6* Predicted DO on June 1st based on:

DO = Slope * Date + Intercept


Water Quality Seasonal DO Decline Nearfield

Annual Oxygen Minimum: Nearfield & Stellwagen, 1992-98

6

6.5

7

7.5

8

6 6.5 7 7.5 8

Nearfield Annual Minimum DO (mg/L)

Ste

llwa

ge

n B

as

in M

inim

um

DO

(m

g/L

)1994

1995

1998

1997

1992

1996

1993

SB = (0.777*NF) + 1.745 R2 = 0.96

The correspondence between the minimum DO in the Nearfield and in Stellwagen Basin provides a reasonable predictor of the DO in Stellwagen Basin bottom waters


Water Quality Baseline Characteristics

Gradients (Nutrients, biomass, and dissolved oxygen)• Temporal • Offshore • Vertical

Tidal exchange and export from Boston Harbor Plankton Communities

• Phytoplankton• Zooplankton


Water Quality Plankton Species

Phytoplankton• Abundance by species or group• Key taxa

– Diatomsa– Microflagelates– Dinoflagelates– Cryptomonad– Nuisance species

- Alexandrium tamerenses - Phaeocystis pouchetii - Pseudo-nitzschia multiseries

Zooplankton/Meroplankton• Abundance by species, group

or stage (adult, copepodite, nauplii)

• Key taxa – Acartia spp.– Oithona spp.– Calanus spp.– Pseudocalanus spp. – Centropages spp.– Polychaete spp. – Mollusca Gastropoda; Bivalvia – Pteropoda spp. – Opisthobranchia spp. – Cirripedia spp


Water Quality Phytoplankton Variability

Phytoplankton abundance in the nearfield generally ranges between a few thousand to 2 million cells/ L

Abundance can range to over 12 million cells/L

Range for individual samples can be large for any given survey

Reflects variability between surface and pycnocline samples

Total Phytoplankton Abundance - Nearfield

0

2

4

6

8

10

12

14

J M S J M S J M S J M S J M S J M S J M S J M S J

10

6 Ce

lls/L

1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Total Phytoplankton Inter-annual and Regional Comparison

Phytoplankton abundance in the farfield areas is generally similar to the nearfield

Occasionally abundance in CCB and the Harbor are larger on average than in the nearfield

Abundance at the boundary Station F27 are lower on occasion

Seasonal patterns are variable although late summer and fall peaks are frequent

Total Phytoplankton Abundance - Area Mean

0

1

2

3

4

5

6

7

8

9

10


10

6 Ce

lls/L

Boundary Nearfield Harbor Cape Cod Bay Coastal

1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Diatoms Diatom abundance

in the nearfield generally ranges between a few thousand to 1 million cells/ L

Occasionally abundance can range to over 12 million cells/L

Range reflects within survey variability

Seasonal patterns are variable and no one year exactly replicates another

Total Diatoms Abundance - Nearfield

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00


10

6 Ce

lls/L

1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Diatoms Diatom abundance

in the farfield areas is generally similar to the nearfield

Abundances in CCB range higher and lower than in the nearfield and the timing of blooms is often different than the nearfield

Abundance at the boundary Station F27 are lower

Coastal stations and Harbor abundance are often similar

Total Diatoms Abundance - Area Mean

0

1

2

3

4

5

6


106 C

ell

s/L


1992 1993 1994 1995 1996 1997 1998 1999

Seasonal diatom abundance is clearly evident but varies in magnitude and timing


Water Quality Microflagellates Microflagellate

abundance in the nearfield generally ranges between a few thousand to 1 million cells/ L

Occasionally abundance can range to over 12 million cells/L

Range reflects within survey variability

Seasonal abundance patterns are variable and no one year exactly replicates another

Total Microflagellates Abundance - Nearfield

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00


10

6 Ce

lls/L

1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Microflagellates

Abundance in the farfield areas is very similar to the nearfield

Abundances in CCB and Harbor are occasionally higher than in the nearfield and the timing of blooms is often different

Seasonal abundance is clearly evident and peaks in the late summer

Total Microflagellate Abundance - Area Mean

0.00

1.00

2.00

3.00

4.00

5.00

6.00


10

6 Ce

lls/L


1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Phytoplankton Community Composition

% Diatoms and % Microflagellates in Total Phytoplankton Abundance

0

10

20

30

40

50

60

70

80

90

100


(%)

% Microflagelates % Diatoms

1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Phytoplankton Community Carbon-based composition

Concerns over carbon cycling and outfall effects on the major taxa in the Bay have resulted in comparison of the phytoplankton community abundance on a carbon basis

Each species is assigned a carbon per cell value and the carbon-based abundance is calculated from abundance and carbon value

The total phytoplankton carbon in the sample is then calculated by summing the various species

Data presentations are developed as shown for the cell abundance data

Focus is on the relative proportions of diatiom carbon and microflagellate carbon



Patterns in total carbon based abundance are similar to the cell based abundance

Survey means show distinct temporal patterns

Within survey and sample variability is high .

Total Phytoplankton Carbon - Nearfield

0

500

1,000

1,500

2,000

2,500


106 p

g C

/L

1992 1993 1994 1995 1996 1997 1998 1999


Phytoplankton Carbon - Area Mean

0

200

400

600

800

1,000

1,200

1,400


106p

gC

/L


1992 1993 1994 1995 1996 1997 1998 1999




% Diatoms and % Microflagelates in Total Phytoplankton Carbon

0

10

20

30

40

50

60

70

80

90

100


(%)

%Microflagelates %Diatoms

1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Phytoplankton Community Nuisance Species

COMPARISON OF SEASONAL NUISANCE SPECIES DATA1992-1998

Species 95th Percentilecells/L

n Baselinecondition

Alexandrium tamerensesWinter-Spring: 0.27Summer: 5.00Fall: 0.97

474420262

Non zero countsin 31 of 1,156samples

Phaeocystis pouchetii Winter-Spring: 0.961Summer: 0.0004Fall: 0 028

528421262

Non zero countsin 93 of 1,122samples

Pseudo-nitzschiamultiseries a

Seasonal (Winter-Spring,Summer, Fall) meanconcentration of confirmedspecies exceed 500,000 cells/L

Pseudo-nitzschiapungens Nonzero counts in438 of 1,122samples

1999 To be added to the estimate of the 95th percentilea Pseudo-nitzschia pungens counts will trigger a SEM confirmation of P. multiseries


Water Quality Phytoplankton Community Summary

Species composition is generally similar among samples from within surveys and among regions

Total abundance varies among samples, survey, season, and regions Distinct temporal patterns are evident, although variability within surveys is high Diatoms and microflagellates are the numerically dominant plankton groups Carbon-based abundance is dominated by diatoms Nuisance species are present sporadically and at low levels Blooms of Phaeocystis pouchetii have occurred twice during the baseline, once

in the spring of the year and once in the fall of the year Alexandrium tamerenses blooms have not occurred since 1993 (see Keefer and

Anderson poster) although species are occasionally observed in low abundance Massachusetts Bay communities are consistent with broader-scale zooplankton

distributions in the Gulf of Maine and Buzzards Bay (see Turner poster)


Water Quality Zooplankton Variability

Zooplankton abundance in the nearfield ranges between a few thousand to 100,000 individuals/ L

Occasionally abundance can range to 150K individuals/L

The range among individual samples is large for any give survey

Total abundance appears increase since 1994

Total Zooplankton Abundance - Nearfield

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000


Ind

ivid

ua

ls/m

3

1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Total Zooplankton Inter-annual and Regional Comparison

Total zooplankton abundance in the farfield regions are generally similar to the nearfield

Total abundance is often lower in Boston Harbor relative to Massachusetts Bay

The general increase in nearfield total abundance since 1994 is reflected in the other offshore regions

Total Zooplankton Abundance - Area Mean

0

50,000

100,000

150,000

200,000

250,000


Ind

ivid

ua

ls/m

3


1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Total Zooplankton Copepod Abundance

Adult and copepodite stages of the non-Acartia spp. copepods show a clear seasonal pattern

Abundance is generally similar throughout the Bay

Lower abundances are observed in Boston Harbor

Cape Cod Bay and the nearfield are generally similar

The highest baseline abundance since 1992 were recorded in the winter/spring of 1999

Threshold Zooplankton Assemblage Total Abundance - Area Mean

0

10,000

20,000

30,000

40,000

50,000

60,000


Ind

ivid

ua

ls/m

3


1992 1993 1994 1995 1996 1997 1998 1999

Oithona spp., Calanus, Pseudocalanus, and Centropages spp.


Water Quality Total Zooplankton Meroplankton Abundance

Meroplankton form minor component of the zooplankton community

The Harbor, CCB, and Coastal abundance in the winter spring of 1999 were the highest observed during the baseline

Meroplankton Abundance - Area Mean

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000


Ind

ivid

ua

ls/m

3


1992 1993 1994 1995 1996 1997 1998 1999

Polychaete spp.; Gastropoda; mollusca, bivalvia spp.; Cirripedia spp


Water Quality Acartia spp. Abundance

Acartia spp. abundance is higher in the Harbor compared to the nearfield

Seasonal patterns (summer maximum) in the Harbor abundance are evident

Acartia Abundance

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000


Ind

ivid

ua

ls/m

3

Nearfield Area Mean Harbor Area Mean1992 1993 1994 1995 1996 1997 1998 1999


Water Quality Draft Zooplankton Threshold

WINTER-SPRING MEAN THRESHOLD ZOOPLANKTON ABUNDANCE INTHE NEARFEILD BY YEAR

Year N Mean Minimum STD Maximum

1992 18 3,888 1,270 1,892 7,6261993 18 3,543 1,280 1,971 8,0371994 18 3,802 1,391 2,252 9,9561995 10 5,553 1,503 3,623 11,7241996 11 6,754 1,088 4,674 14,8751997 12 8,718 3,434 3,376 14,4141998 11 10,917 211 6,860 20,5131999 11 24,244 17 55,381 184,913

Draft threshold based on the 5th percentile of the baseline means = 3,453 individuals/LBased on the sum of the adult and copepodite stages of two Oithona species, Calanus,Pseudocalanus, and Centropagestypicus


Water Quality Zooplankton Community Summary

Community composition among samples from a survey, within seasons, or among farfield regions are generally similar

Abundance varies among samples, survey, season, and regions

Although variability within surveys is high distinct temporal patterns are evident in the data

Massachusetts Bay communities are consistent with broader scale zooplankton distributions in the Gulf of Maine and Buzzards Bay (see Turner poster)


Water Quality Baseline Monitoring Summary

Baseline data indicate that water parameters are highly variable in the nearfield (esp. western nearfield)

Seasonal and inter-annual variability Inshore/offshore gradients in nutrients, chlorophyll, and DO Plankton populations are similar offshore; Harbor differences

are event relative to offshore populations and abundance Plankton respond in a relatively predictable manner in this

system Ability of the monitoring program to detect change before any

given threshold is reached is high


Expectations of changes in water quality after transfer to Massachusetts Bay

Harbor Response• Nutrients field in the outer Harbor will decrease in

concentration and extent• Chlorophyll levels will decrease in the Harbor and

western nearfield • Abundance of offshore zooplankton in the outer

Harbor may increase if salinity increases• Phytoplankton species composition remain similar to

those present now

Because the new outfall relocates the current discharge to a deeper depth that is generally below the photic zone and will achieve much higher dilution than is currently achieved at the Deer Island outfall, the net ecological impact is likely to be small and limited to the nearfield.


Expectations of changes in water quality after transfer to Massachusetts Bay

Massachusetts Bay Response• total nutrient fields are not expected to change appreciably in the

vicinity of the outfall, although a nutrient signal against a lower offshore background especially for NH4 may be observed

– Plume tracking and nearfield monitoring will evaluate this • Coastal plume will be less distinct and less intense• Chlorophyll levels will decrease in surface waters of the western

nearfield • Little or no change in the zooplankton community composition or

abundance • Phytoplankton species composition will see little or no change• Bottom water DO values are not expected to change substantially

relative to the current baseline history

OMSAP Public Meeting September 1999 Water Quality Monitoring Program and Baseline Results OMSAP...

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