PARENT SESSION
Symposium 1: In the Footsteps of Lewis and Clark: Rediscovering Earth From Land to Sea - A Biogeoscience Perspective.
Organized by: PV Sundareshwar and J Elser
Monday, August 2, 8:00 AM to 11:30 AM, Oregon Ballroom 202.

Updating Redfield Relationships for oceans and lakes.

Sterner, Robert^*,1, ¹ University of Minnesota, St. Paul

ABSTRACT- Particulate C:N:P ratios have been a cornerstone of ecological stoichiometry. Years ago, Alfred Redfield suggested that plankton have a composition of 106:16:1 and in more recent times different ratios for freshwater systems have been proposed. Here, I will report on a compilation of particulate C:N:P ratios for offshore and nearshore marine samples as well as freshwater lakes. Globally, C:N:P is closer to 150:17:1 than to Redfield's values, suggesting the "Redfield Ratio" needs to be updated. More interestingly, however, C:N:P shifts consistently with production in both marine and freshwaters, so the ratios are not constant (plus or minus some variation) but rather are better represented as power functions. Across the entire global data set, however, those shifts are not observed. Hypotheses for these differences in ratio shifts within and across systems will be discussed.

Key words: lake, C:N:P, stoichiometry, ocean