Comparing seasonal dynamics of the Lake Huron zooplankton community between 1983–1984 and 2007 and revisiting the impact of Bythotrephes planktivory

Lake Ontario zooplankton in 2003 and 2008: Community changes and vertical redistribution

“…This species is known to have large impacts on North American pelagic zooplankton (Yan et al, 2011) and has been implicated in declines in cladocerans in Lake Michigan (Lehman and C aceres, 1993;Schulz and Yurista, 1995;Barbiero and Tuchman, 2004;Vanderploeg et al, 2012), Lake Huron (Bunnell et al, 2011;Bunnell et al, 2012), and smaller lakes (Wahlstr€ om and Westman, 1999;Yan et al, 2001Yan et al, , 2011Hoffman et al, 2001;Strecker and Arnott, 2008). In addition, Bythotrephes is known to induce vertical migration in daphniids and some copepods in the laboratory (Pangle et al, 2007;Bourdeau et al, 2011); an effect also observed in field studies from Lake Michigan (Bourdeau et al, 2011) and elsewhere (Hessen et al, 2011;Jokela et al, 2011).…”

Mercury biomagnification and contemporary food web dynamics in lakes Superior and Huron

“…that were introduced in the Great Lakes beginning in the late 1980s, have been implicated in the dramatic and rapid alterations in the food web structure of the affected ecosystems, especially in Lake Huron (Barbiero et al, 2009;Bunnell et al, 2012;Schaeffer et al, 2005;Vanderploeg et al, 2002). The sequestration of particulate nutrients driven by the efficient filtering of seston from the water column by Dreissena spp.…”

Improved estimates of calanoid copepod biomass in the St. Lawrence Great Lakes

“…Total wet settled volume can be used to measure total community biomass, but to obtain taxon or specieslevel information it is common to measure animal lengths and then to use allometric models called length-weight regressions to estimate weights (Strickland and Parsons, 1968;Dumont et al, 1975;Bottrell et al, 1976;Downing and Rigler, 1984;Culver et al, 1985). Estimates of zooplankton biomass thus obtained are routinely used to assess changes in species composition and food web relations (e.g., Vanderploeg et al, 1992Vanderploeg et al, , 2012Barbiero et al, 2009Barbiero et al, , 2012Bunnell et al, 2012).…”

“…A series of papers report notable changes in the zooplankton communities of Lakes Michigan and Huron, with increases in calanoid copepod biomass and decreases in cyclopoid copepods and Cladocera in both lakes (Barbiero et al, 2009;Doubek and Lehman, 2011;Bunnell et al, 2012;Vanderploeg et al, 2012). Unfortunately, there does not appear to be consensus about the scaling metrics used to predict individual biomass from individual size.…”