Hi Bob, is it real?

Thirty years ago, Bob and I did a simple experiment to investigate how the LIGHT-NUTRIENT BALANCE affects secondary production by changing the chemical quality of the primary producers. In that experiment, we found that when the supply of nutrients such as phosphorus was low, high light conditions reduced the growth rate of Daphnia species despite an increase in algal food abundance. We hypothesized that high light and low nutrient supply would reduce daphnia growth rate because the amount of phosphorus relative to carbon in the algal food was low compared to the requirements of daphnia for healthy growth. But was daphnia growth really reduced by a lack of phosphorus?  Bob and I wondered if there was a “smart” way to answer this question. One day I learned that Daphnia are good animals because they have the ability to drink water from their anus! So, Bob and I decided that we would use this ability to confirm that the low growth rate of daphnia was due to phosphorus deficiency. Bob and I, along with Jessica Clasen who was a summer student in the Sterner labs at the time, set up experiments in which we immersed daphnia individuals in a solution of highly concentrated phosphorus for a few hours a day to allow them to enjoy anal drink.  Here I will talk about how that experiment went and what happened afterwards with some eipsodes on Bob Sterner.

Primary Presenter: Jotaro Urabe, Tohoku University (urabe@tohoku.ac.jp)

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