Abstract
Transmission of topโdown control from fish to phytoplankton via crustacean mesozooplankton is a cornerstone of limnetic plankton ecology. Such trophic cascades are less frequently reported from the marine pelagic. In this article a case is made for consideration of scale issues and for the distinction between full (affecting entire trophic levels) and partial (affecting only some functional groups) trophic cascades. Partial cascades are more widespread while the full cascades are either ephemeral or depend on the suppression of compensatory growth of the predationโresistant sizeโfractions of phytoplankton. This suppression can only be achieved if there is a persistent coexistence between zooplankton feeding on different parts of the phytoplankton size spectrum. This condition is fulfilled in plankton communities where microphageous cladocerans (mainly Daphnia) and microphageous copepods coexist (many lake communities) or where krill and copepods coexist (high latitude marine communities). It is not fulfilled in many temperate and lowโlatitude marine communities where copepods effectively suppress filterโfeeding appendicularians. Thus, the observed difference in the frequency of marine and limnetic pelagic cascades is considered real.
Are all trophic cascades wet?
Strong et al., 1992 (ยฉ 2008 WILEYโVCH Verlag GmbH & Co. KGaA, Weinheim)