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BENTHIC COMMUNITY STRUCTURE AND BIODIVERSITY BENTHIC COMMUNITY STRUCTURE AND BIODIVERSITY FOLLOWING SEWAGE ABATEMENT PROGRAMS IN BOSTON FOLLOWING SEWAGE ABATEMENT PROGRAMS IN BOSTON
HARBOR HARBOR
By
James A. Blake, Nancy J. Maciolek ENSR Marine & Coastal Center, Woods Hole, MA
&Kenneth Keay
Massachusetts Water Resources Authority, Boston, MA
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Clean-up of Boston HarborClean-up of Boston Harbor
End Sludge disposal (1991)
Development of New Sewage Treatment Facilities and offshore outfall
Upgrade Sewage to Secondary Treatment (1997–2000)
Transfer Sewage Outfalls from Boston Harbor To Massachusetts Bay (September 2000)
On-going CSO improvement program
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Benthic Community Monitoring in Boston HarborBenthic Community Monitoring in Boston Harbor
Surveys performed for the MDC as part of the 301(h) Waiver Applications: 1978, 1979, 1982
Formal Monitoring by MWRA began in September 1991
April and August Sampling from 1992−2002
August Sampling continued since 2003
Total of 17 Years of Benthic Monitoring: August/September 1991−2007 and continuing
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Nitrogen Loading and Sewage Abatement in Boston Nitrogen Loading and Sewage Abatement in Boston Harbor Harbor (after Taylor, 2006)(after Taylor, 2006)
PERIOD I PERIOD II PERIOD III PERIOD IV
YEAR 1991 1995 1997–2000 1998 2000
Nitrogen SourcesDeer Island and
Nut Island Outfalls
Deer Island and Nut Island Outfalls
Deer Island Outfall Mass Bay Outfall
MILESTONESludge
dumping endsNew primary
treatment at DI
Upgrade to Secondary
Treatment at DI
Nut Island discharge
transferred to Deer Island (Inter-Island
transfer tunnel)
Deer Island Discharge
transferred from Boston Harbor to Mass Bay outfall
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Benthic Sampling Benthic Sampling Stations in Stations in
Boston HarborBoston Harbor19911991−−20072007
T01: Deer Island Flats
T02: Governor’s Island Flats
T03: Long Island
T04: Dorchester Bay
T05A: President Roads
T06: Peddocks Island
T07: Quincy Bay
T08: Hingham Bay
C019: Inner Harbor CSO
Deer Island
Hingham/Hull Bay
Quincy Bay
Dorchester Bay
Presidents Roads
Little Brewsters
Broad Sound
42°2
3'42
°22'
42°2
1'42
°20'
42°1
9'42
°18'
42°1
7'42
°16'
42°1
5'42
°14'
71°00'71°01'71°02'71°01' 70°59' 70°58' 70°57' 70°56' 70°54' 70°53'70°55'
71°00'71°01'71°02'71°01' 70°59' 70°58' 70°57' 70°56' 70°54' 70°53'70°55'
42°23'42°22'
42°21'42°20'
42°19'42°18'
42°17'42°16'
42°15'42°14'
Kilometers
0 1 2 3
NGrab stations
Boston Harbor Stations
T01
T02
T03
T04
T06
T07 T08
T05A
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Deployment of the Deployment of the Ted Young grab Ted Young grab samplersampler
0.04-m0.04-m22 surface area surface area
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Looking for Evidence of ChangeLooking for Evidence of Change Changes in Faunal Abundance (density of organisms)
Changes in Species Richness (numbers of species)
Changes in Species Composition (i.e., opportunistic or stress-resistant species replaced by others)
Changes in Species Assemblages (community structure; functional groups)
Changes in Species Diversity (H′, ESn, Log-series alpha)
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Changes in Faunal AbundanceChanges in Faunal Abundance
Boston Harbor
0
2000
4000
6000
8000
10000
12000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Tota
l Abu
ndan
ce
Mean+/- 1SE
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Long-term Trends in Species RichnessLong-term Trends in Species Richness
Boston Harbor
05
10
1520253035
4045505560
657075
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Nu
mb
er o
f Tax
a
Mean+/- 1SE
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Long-term Trends in Species Diversity: Long-term Trends in Species Diversity: alphaalpha
Boston Harbor
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Log-
serie
s A
lpha
Mean+/- 1SE
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Benthic parameters summarized by time periods Benthic parameters summarized by time periods defined by Taylor (2006) defined by Taylor (2006)
Parameter
Period
I−II III IV
1991–1998 1999–2000 2001–2005
Number of Samples n = 192 N = 47 n = 120
Number of Species 32.3 ± 14.3 32.0±12.5 42.3 ± 18.0
H′ (base 2) 2.3 ± 0.9 2.8 ± 0.8 2.9 ± 0.8
log-series alpha 5.2 ± 2.1 5.9 ± 1.9 7.7 ± 3.0
ESn (rarefaction curves )
low high highest
Fauna
higher abundancesof opportunistic species such as Streblospiobenedicti andPolydora cornuta
Feweropportunists,more oligo-chaetes, somespecies from Massachusetts Bay
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Changes to Boston Harbor Benthos in 2005Changes to Boston Harbor Benthos in 2005
Amphipod mats entirely absent in 2005 Shifted from a biologically to physically dominated sediment surface
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AmpeliscaAmpelisca Abundance: 1991 Abundance: 1991––20072007
Ampelisca spp. Total number sampled by grab at eight Boston Harbor stations each August
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Tota
l Num
ber p
er S
ampl
ing
Dat
e
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Some benthic invertebratesSome benthic invertebrates in Boston Harbor in Boston Harbor
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
To
tal A
bu
nd
an
ce
Ampelisca spp. Nephtys cornuta Polydora cornuta Aricidea catherinae
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Nephtys Nephtys cornutacornutaAdultsAdults
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Nephtys Nephtys cornutacornutalarvaelarvae
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Amphipod Population Crash in 2005Amphipod Population Crash in 2005
– Loss of habitat diversity
– Commensurate decline in species richness and diversity in 2005 and 2006
– Populations stayed low in 2006, but slight recovery is evident in 2007
– Long-term reduction in organic loadings
– Two unusual spring 2005 Nor’easters contributed to amphipod population crash
– Over-wintering adults swim into the water column in the spring and the storms are believed to have caught these individuals and swept them away
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Deer Island
Hingham/Hull Bay
Quincy Bay
Dorchester Bay
Presidents Roads
Little Brewsters
Broad Sound
42°2
3'42
°22'
42°2
1'42
°20'
42°1
9'42
°18'
42°1
7'42
°16'
42°1
5'42
°14'
71°00'71°01'71°02'71°01' 70°59' 70°58' 70°57' 70°56' 70°54' 70°53'70°55'
71°00'71°01'71°02'71°01' 70°59' 70°58' 70°57' 70°56' 70°54' 70°53'70°55'
42°23'42°22'
42°21'42°20'
42°19'42°18'
42°17'42°16'
42°15'42°14'
Kilometers
0 1 2 3
NGrab stations
Boston Harbor Stations
T01
T02
T03
T04
T06
T07 T08
T05A
Long-Term Results Long-Term Results for Individual Stations for Individual Stations
19911991−−20072007
T01 Deer Island Flats: significant improvement in species diversity and complete change in community structure
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Total Abundance at Station T01 (1991−2005)Total Abundance at Station T01 (1991−2005)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
To
tal A
bu
nd
ance
T01 Mean +/- 1 SE
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Diversity (Diversity (log-series og-series alphaalpha) at Station T01 ) at Station T01 (1991−2006)(1991−2006)
0
1
2
3
4
5
6
7
8
9
10
11
12
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
Lo
g-s
erie
s A
lph
a
T01 Mean +/- 1 SE
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22
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PCA-H analysis of T01: 1991–2007PCA-H analysis of T01: 1991–2007
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Euclidean Euclidean Distance Distance BiplotBiplot
Station T01 Deer Island Flats (1991(1991––2007)2007)
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Overall Conclusions Relative to Sewage Overall Conclusions Relative to Sewage Diversion from Boston Harbor to Diversion from Boston Harbor to
Massachusetts BayMassachusetts Bay
Benthic communities in Boston Harbor have improved significantly since the diversion to the new outfall in September 2000
There is no evidence of any adverse impact on the infaunal benthos of Massachusetts Bay or Cape Cod Bay since the new outfall came on-line
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AcknowledgementsAcknowledgements
Massachusetts Water Resources Authority is thanked for supporting this long-term monitoring program and leading the effort to clean up Boston Harbor
Field programs were successfully led by Isabelle P. Williams & Pamela Neubert
Laboratory analyses were managed by Isabelle Williams and Stacy Doner; important taxonomic contributions have been made by Brigitte Hilbig, Russ Winchell, Gene Ruff, Tim Morris, & Nancy Mountford
Interpretation has been enhanced by contributions from Bob Diaz, Don Rhoads, Gene Gallagher & Roy Kropp
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