Changes in phytoplankton community structure during the zebra mussel (Dreissena polymorpha) invasion of the Hudson River (New York)

We analyzed differences in the cell density and taxonomic composition of phytoplankton assemblages in the tidal, freshwater portion of the Hudson River to assess the impact of the recent zebra mussel invasion. In order to assess this change, phytoplankton genera were identified and counted during two representative periods, 1987-88 (before zebra mussel invasion) and 1993-94 (after invasion) and major groups in 199S and 1996. Average cell density of phytoplankton declined -17-fold from 25.6 x 10 6 cells H before invasion to 1.5 x 10 6 cells I"1 after invasion. Dominance of the phytoplankton (by cell density, assessed on an annual scale) shifted from cyanobacteria before the invasion to diatoms during the invasion; cyanobacterial density decreased 778-fold and diatoms decreased by a factor of only 2.5. Samples from 1995 and 1996, counted only to class, confirm the patterns from the more detailed counts in 1993 and 1994: a major decline in cell numbers and a dramatic decline in cyanobacteria relative to diatoms. The taxonomic composition of assemblages based on relative abundances of both genera and divisions showed significant shifts from colonial and unicellular cyanobacteria to large, colonial or benthic diatoms. Also, the large decline in cyanobac- teria and some diatom genera, which had been abundant in late summer, dampened the seasonal variation in the taxonomic composition of phytoplankton following the zebra mussel invasion.

[1]  M. Moran,et al.  The Hudson River Ecosystem , 1986 .

[2]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[3]  M. Sprung.  Field and laboratory observations of Dreissena polymorpha larvae: abundance, growth, mortality and food demands , 1989, Archiv für Hydrobiologie.

[4]  David L. Strayer,et al.  Projected Distribution of the Zebra Mussel, Dreissena polymorpha, in North America , 1991 .

[5]  B. K. Sullivan,et al.  Interactions with the benthos alter pelagic food web structure in coastal waters , 1991 .

[6]  M. Pace,et al.  Weak coupling of bacterial and algal production in a heterotrophic ecosystem: The Hudson River estuary , 1991 .

[7]  B. L. Peierls,et al.  Can phytoplankton maintaina positive carbon balance in a turbid, freshwater, tidal estuary? , 1992 .

[8]  K. Nicholls,et al.  Recent Changes in Lake Erie (North Shore) Phytoplankton: Cumulative Impacts of Phosphorus Loading Reductions and the Zebra Mussel Introduction , 1993 .

[9]  R. Holland,et al.  Changes in Planktonic Diatoms and Water Transparency in Hatchery Bay, Bass Island Area, Western Lake Erie Since the Establishment of the Zebra Mussel , 1993 .

[10]  T. Nalepa,et al.  Zebra mussels : biology, impacts, and control , 1993 .

[11]  R. Lowe,et al.  Shifts in Benthic Algal Community Structure and Function Following the Appearance of Zebra Mussels (Dreissena polymorpha) in Saginaw Bay, Lake Huron , 1995 .

[12]  T. Nalepa,et al.  Dreissena polymorpha in the Saginaw Bay, Lake Huron Ecosystem: Overview and Perspective , 1995 .

[13]  Wayne S Gardner,et al.  Ecosystem-Level Effects of Zebra Mussels (Dreissena polymorpha): An Enclosure Experiment in Saginaw Bay, Lake Huron , 1995 .

[14]  Gregory A. Lang,et al.  Effects of Zebra Mussel (Dreissena polymorpha) Colonization on Water Quality Parameters in Saginaw Bay, Lake Huron , 1995 .

[15]  H. MacIsaac,et al.  Potential Abiotic and Biotic Impacts of Zebra Mussels on the Inland Waters of North America , 1996 .

[16]  R. Howarth,et al.  Metabolism and organic carbon fluxes in the tidal freshwater Hudson River , 1996 .

[17]  M. Pace,et al.  Arrival, spread, and early dynamics of a zebra mussel (Dreissena polymorpha) population in the Hudson River estuary , 1996 .

[18]  N. Caraco,et al.  Carbon dioxide concentration and atmospheric flux in the Hudson River , 1997 .

[19]  David L. Strayer,et al.  ZEBRA MUSSEL INVASION IN A LARGE, TURBID RIVER: PHYTOPLANKTON RESPONSE TO INCREASED GRAZING , 1997 .

[20]  Jonathan J. Cole,et al.  Experimental measurements of zebra mussel (Dreissena polymorpha) impacts on phytoplankton community composition , 1998 .

[21]  M. Pace,et al.  Effects of an invasive bivalve on the zooplankton community of the Hudson River , 1998 .

[22]  David L. Strayer,et al.  Transformation of Freshwater Ecosystems by Bivalves A case study of zebra mussels in the Hudson River , 1999 .