The nutrition of radiolarians: Trophic activity of some solitary Spumellarial

• Main Authors: Neil R. Swanberg, Roger Anderson
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Planktonic foraminifera
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.550.5626; http://www.aslo.org/lo/toc/vol_30/issue_3/0646.pdf

Four species of radiolarians were kept in the laboratory under different feeding regimes. Spon-godrymus sp. and two species of Thalussicolla showed no difference in survivorship between herbivorous, carnivorous, omnivorous, or nonfed conditions as long as they were kept in the light. The longest surviving individuals of the three species lived 32,44, and 34 d. All these species bear copious numbers of algal symbionts, suggesting a significant algal role in host nutrition. A fourth species, Physematium muelleri, survived significantly longer on an omnivorous diet and was found to feed omnivorously in nature, with a diet reflecting the locally available microplankton. Protozoa are often very abundant among the tropical marine surface plankton and the Rhizopoda are frequently the most notice-able. Foraminifera, acantharia, and radi-olaria are so common and abundant in the tropical and subtropical plankton that their numbers can seemingly overwhelm most other groups (BE: et al. 1977; Swanberg 1979, 19 8 3; Anderson 19 8 3). An understanding of the trophic interactions of these groups with other components of the plankton is essential to any complete planktonic model. Considerable advances have been made in our understanding of the biology of the planktonic foraminifera (Be et al. 1977; An-derson et al. 1979), but since less is known about other planktonic protista we cannot at present make many generalizations about comparative biology. Recent work with co-lonial and solitary Spumellaria (Anderson