Oneida Lake: Long-term Dynamics of a Managed Ecosystem and Its Fishery

Chapter 9: The Zebra Mussel Invasion of Oneida Lake: Benthification of a Eutrophic Lake

Christine M. Mayer, Bin Zhu, and Rebecca Cecala

doi: https://doi.org/10.47886/9781934874431.ch9

Zebra mussels Dreissena polymorpha have expanded their range throughout much of the eastern United States since they were introduced to Lake St. Clair in 1986 (Hebert et al. 1989) and the conspecific quagga mussel D. bugensis has since spread across much of the Great Lakes (Stoeckmann 2003). Dreissena spp. have been accredited with a variety of ecological impacts but the two most consistent effects in lakes are: 1) a local increase in benthic invertebrate density in mussel druses and 2) a decrease in the standing crop of phytoplankton and subsequent increase in water clarity. The effect of mussel druses on invertebrate density operates on a local spatial scale whereas the alteration of water clarity operates on a system-wide spatial scale (Mayer et al. 2002). However, both of these phenomena are best described as ecosystem engineering (sensu Jones et al. 1997) because they cause physical state changes in the system and alter the flow of organic materials and energy. We use the term “benthification” for the combined local and system-wide effects of zebra mussels increasing the importance of benthic relative to pelagic processes in lakes (Zhu et al. 2006).

The increase in water clarity associated with the establishment of a zebra mussel population (Mayer et al. 2000; Idrisi et al. 2001) is likely to propagate a series of alterations in ecosystem structure (e.g., species composition, spatial distribution of organisms) and ecosystem function (e.g., primary production, benthic-pelagic flux). When phytoplankton concentration is high, it shades benthic habitats and limits light to primary producers in deeper areas. Increasing water clarity will affect the lake in a manner similar to cutting down trees in a forest, restructuring the spatial distribution of primary production, organic material and energy flow. As lakes shift from turbid to benthified, a predictable suite of changes should arise (Figure 1). The spatial extent of potential benthic primary production (algae and macrophytes) will increase because sufficient light reaches a greater proportion of the bottom. Pelagic primary production may or may not change as standing crop declines, but the amount of detrital rain to the profundal zones of lakes should decrease, whereas direct importation of organic material will increase due to Dreissena filtering. Further, the rate of flux of materials from benthic to pelagic zones should increase, as visually feeding fish will be more efficient foragers on benthic invertebrates due to greater light penetration. The overall effect of benthification will be to increase the production and flux of organic material from the lake’s bottom.