Food Web Structure and Phosphorus Cycling in Lakes
- 1 September 1993
- journal article
- Published by Oxford University Press (OUP) in Transactions of the American Fisheries Society
- Vol. 122 (5) , 756-772
- https://doi.org/10.1577/1548-8659(1993)122<0756:fwsapc>2.3.co;2
Abstract
We assessed the effects of trophic structure on phosphorus (P) recycling by fishes, Chaoborus, and zooplankton in lakes with different food web configurations. Fishes in a piscivoredominated system recycled little P compared to that regenerated by zooplankton and Chaoborus. In a plan ktivore-dominated lake, excretion by fishes (especially young of year) dominated P recycling to algae; Chaoborus and zooplankton recycling was decreased due to intense predation by fishes. The sum of P incorporated into primary production and lost to sedimentation in the piscivore-dominated lake was only 77% of that in the planktivore-dominated lake, Our analyses suggest that the 30% greater primary production in the planktivore-dominated system may be accounted for by the greater than 40% increase in estimated P recycling that was directly due to differences in food web structure, Diel vertical migrations by Chaoborus concentrated P excretion in the epilimnion during night hours. In the plan ktivore-dominated system...Keywords
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