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Lower trophic levels and alewife in Onondaga Lake 2011 Presentation for OLTAC meeting Halloween 2012. Phytoplankton in 2011. Synedra. Cyclotella. Bluegreens 2011. Biovolume 1998-2011. Phytoplankton 1998-2011. N:P ratio. Zooplankton. Daphnia. Calanoids. Cladocerans. Copepods. Bosmina.
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Lower trophic levels and alewife in Onondaga Lake 2011 Presentation for OLTAC meeting Halloween 2012
Phytoplankton in 2011 Synedra Cyclotella
Zooplankton Daphnia Calanoids Cladocerans Copepods Bosmina Cyclopoid
Alewife Daphnia
Cascading interactions in the food chain Alewife Zooplankton Algae
2010 – 60% from the 2009 year class 2011 - 74% from the 2009 year class 26% from the 2010 year class 2012 28% 2009, 13% 2010, 52% 2012
Water Quality Effects • Smaller zooplankton • “Top-down” trophic cascades: increasing algae
Secchi 2008-2012 2008 2009 2010 2011 2012
Density # /m2 • Oneida 1995 – 2009: 6300 (3600 – 9400) • Onondaga 2007 – 2011: 13000-18000
Trophic Cascades 2008 - 2011 Alewife Algae and Water Clarity Nutrients
Winter Mortality Champlain January 2008