Vertical Distribution of Phytoplankton

Understanding spatial heterogeneity is a key question in ecology in general and biological limnology and oceanography in particular. In lakes and the ocean horizontal mixing rates are orders of magnitude greater than vertical mixing rates, causing the vertical axis to be the primary axis of heterogeneity. The most prominent vertical aggregations of phytoplankton are Deep Chlorophyll Maxima (DCMs), benthic layers and surface layers, where up to 90% of total biomass is concentrated in a relatively thin layer. Poor mixing and the opposing gradients in light and nutrient are thought to contribute to the formation of algal vertical aggregations. Even in well-mixed water columns, there is an unavoidable vertical gradient in light. Vertical structure in aquatic ecosystems has many implications, affecting primary productivity, controlling sedimentation fluxes of carbon, and modifying zooplankton feeding and mating rates. Deep chlorophyll maxima may make the remote sensing estimates of primary production inaccurate, as the depth of DCM is usually below the optical depth of chlorophyll detection. In this project we combine laboratory experiments in plankton towers and modeling to examine what mechanisms are responsible for the formation and maintenance of vertical heterogeneity in phytoplankton.

Jarad counting algae on CASY counter

Personnel

Lab Members

Elena Litchman, Christopher Klausmeier, Kohei Yoshiyama, Jarad Mellard, Ally Hutchens and Pam Woodruff

Collaborators

Sebastian Diehl, Christoph Jäger and Silvia Bartholmé (LMU, Germany)

Publications

Yoshiyama, K., J.P. Mellard, E. Litchman and C.A. Klausmeier. In press. Phytoplankton competition for nutrients and light in a stratified water column. American Naturalist.

Klausmeier, C.A. and E. Litchman. 2001. Algal games: the vertical distribution of phytoplankton in poorly mixed water columns. Limnology and Oceanography, 46: 1998-2007.

Reprint (693KB PDF) :: Web Appendix (83KB PDF)

Financial Support

Litchman, E., and C. A. Klausmeier. 2005-2008. Vertical Distribution of Phytoplankton. NSF, Ecology Program (DEB-0610531)

Last updated: March 13, 2009