Effects of feeding frequency on life processes of the planktonic foraminifer Globigerinoides sacculifer in laboratory culture

Abstract

Globigerinoides sacculifer (Brady), a common planktonic foraminifer collected by SCUBA off Barbados, was maintained under six feeding regimes at constant light and temperature conditions. Five groups of 63 specimens each were fed 1-day-old Anemia at the rate of one nauplius per specimen every 1, 2, 3, 4 or 7 days. A starved control group received no Anemia. The rate of chamber formation and shell size increased proportional to the feeding frequency. However, an inverse correlation existed between survival time and feeding frequency. Normally, survival time ends with gametogenesis which terminates the life of the mother cell. Organisms fed more frequently reached maturity and underwent gametogenesis more rapidly than those fed less frequently. The average survival time of G. sacculifer in culture ranged from 7 days for the daily-fed group to 11 days for the group fed every 7 days. While the latter grew more slowly they eventually reached maturity. Starved individuals rarely formed chambers and often died without undergoing gametogenesis. Symbiotic zooxanthellae presumably prolonged survival of starved organisms. Extrapolation of survival data suggests G. sacculifer has a variable life span of 2 to 4 weeks depending on food availability.