Seasonal relative influence of food quantity, quality, and feeding behaviour on zooplankton growth regulation in coastal food webs

• Published in: Journal of the Marine Biological Association of the United Kingdom 2010-09, Vol.90 (6), p.1189-1201
• Main Authors: Vargas, C.A., Martínez, R.A., Escribano, R., Lagos, N.A.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Bacillariophyceae; Biological and medical sciences; Biomass; Carbon; Coastal ecosystems; Copepoda; Crustaceans; diatoms; dinoflagellates; Energy transfer; Environmental effects; Experiments; Fatty acids; Feeding behavior; Food chains; Food quality; food quantity; Food webs; Fundamental and applied biological sciences. Psychology; Growth factors; Ingestion; Mammalia; Marine; Oceans; Plankton; Sea water ecosystems; Seasonal variations; Synecology; Trophic levels; upwelling; Vertebrata; Zooplankton; zooplankton growth
• ISSN: 0025-3154; 1469-7769
• DOI: 10.1017/S0025315409990804

In aquatic food webs zooplankton constitutes an important link between primary producers and higher trophic levels. Copepods often dominate the zooplankton in coastal oceans and are the prey of the majority of planktivorous fish. Feeding behaviour, as well as the food quantity and quality are recognized factors that affect copepod growth, and therefore, the energy transfer efficiency throughout food webs. The natural occurrence and magnitude of these growth factors and their combined effects on marine copepods, as keystone grazers in the pelagic marine realm, are poorly understood. Here, we assessed how these different factors vary throughout the year, and then examine their relative influence upon copepods maximal growth rates. A multiple regression model, including all variables previously selected, and the inclusion of the sea temperature allowed us to estimate the pure influence of the studied factors, and the environmental effect on copepod growth rates. The results imply that ingestion of diatoms may induce a positive effect on specific growth rates of copepods, and the quality of this food item (high PUFA and HUFA availability) might explain such effect. Therefore, seasonal variability in diatom abundance, possibly driven by changes in the oceanographic regime, should be considered a critical factor controlling copepod growth in productive coastal ecosystems.