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Clean-up of Boston Harbor

BENTHIC COMMUNITY STRUCTURE AND BIODIVERSITY FOLLOWING SEWAGE ABATEMENT PROGRAMS IN BOSTON HARBOR By James A. Blake, Nancy J. Maciolek ENSR Marine & Coastal Center, Woods Hole, MA & Kenneth Keay Massachusetts Water Resources Authority, Boston, MA. Clean-up of Boston Harbor.

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Clean-up of Boston Harbor

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  1. BENTHIC COMMUNITY STRUCTURE AND BIODIVERSITY FOLLOWING SEWAGE ABATEMENT PROGRAMS IN BOSTON HARBOR ByJames A. Blake, Nancy J. Maciolek ENSR Marine & Coastal Center, Woods Hole, MA&Kenneth KeayMassachusetts Water Resources Authority, Boston, MA

  2. Clean-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

  3. Benthic 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

  4. Nitrogen Loading and Sewage Abatement in Boston Harbor (after Taylor, 2006)

  5. Benthic Sampling Stations in Boston Harbor1991−2007 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

  6. Deployment of the Ted Young grab sampler 0.04-m2 surface area

  7. Looking 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)

  8. Changes in Faunal Abundance

  9. Long-term Trends in Species Richness

  10. Long-term Trends in Species Diversity: alpha

  11. Benthic parameters summarized by time periods defined by Taylor (2006)

  12. Changes to Boston Harbor Benthos in 2005 Amphipod mats entirely absent in 2005 Shifted from a biologically to physically dominated sediment surface

  13. Ampelisca Abundance: 1991–2007

  14. Some benthic invertebrates in Boston Harbor

  15. Nephtys cornuta Adults

  16. Nephtys cornuta larvae

  17. Amphipod 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

  18. Long-Term Results for Individual Stations 1991−2007 T01 Deer Island Flats: significant improvement in species diversity and complete change in community structure

  19. Total Abundance at Station T01 (1991−2005)

  20. Diversity (log-series alpha) at Station T01 (1991−2006)

  21. PCA-H analysis of T01: 1991–2007

  22. Euclidean Distance BiplotStation T01 Deer Island Flats(1991–2007)

  23. Overall Conclusions Relative to Sewage Diversion from Boston Harbor to Massachusetts 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

  24. Acknowledgements 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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