Evidence suggests that marine and freshwater zooplankton generally experience food levels above subsistence values in terms of carbon. However, the quality of this food may be poor due to an insufficiency of other essential nutrients. In this review, we examine recent progress in three main areas of food quality research: (1) elemental (especially P) limitation, (2) digestion resistance, and (3) biochemical (especially fatty acids) limitation. We evaluate laboratory and field evidence in each of these areas, look at new evidence about the life history implications of the elemental limitation hypothesis, and suggest future avenues for research. From a rather large number of seemingly heterogeneous studies, a single consistent picture of food quality emerges: both P and essential fatty acids are predicted to be important dietary factors, but at different places and times. Nevertheless, despite an abundance of valuable laboratory studies, our knowledge of food quality limitation in the field is still poor.
Bibliographical noteFunding Information:
We thank Ramesh Gulati for the invitation to write this review, and for organizing an earlier symposium on the subject of food quality in zooplankton, which helped greatly stimulate discussion in this field. He and Bill DeMott shared unpublished work. Amy Galford, Bill DeMott, and two anonymous reviewers read the manuscript and provided helpful comments. We thank Bill DeMott, Jim Elser and Jotaro Urabe for numerous discussions. The National Science Foundation provided financial support.
Copyright 2004 Elsevier Science B.V., Amsterdam. All rights reserved.
- Fatty acid
- Food limitation
- Life history