Light-dependent phagotrophy in the freshwater mixotrophic chrysophyte Dinobryon cylindricum |
| |
Authors: | David A. Caron Robert W. Sanders Ee Lin Lim Celia Marrasé Linda A. Amaral Sheri Whitney Rika B. Aoki Karen G. Porters |
| |
Affiliation: | (1) Biology Department, Woods Hole Oceanographic Institution, 02543 Woods Hole, Massachusetts, USA;(2) Division of Environmental Research, Academy of Natural Sciences of Philadelphia, 19103 Philadelphia, Pennsylvania, USA;(3) Institut de Ciències del Mar, Passeig Nacional, s/n, 08003 Barcelona, Spain;(4) NASA/Ames Research Center, MS 242-4, 94035-1000 Moffett Field, California, USA;(5) Department of Zoology, University of Georgia, 30602 Athens, Georgia, USA |
| |
Abstract: | The mixotrophic (bacterivorous), freshwater chrysophyte Dinobryon cylindricum was cultured under a variety of light regimes and in bacterized and axenic cultures to investigate the role of phototrophy and phagotrophy for the growth of this alga. D. cylindricum was found to be an obligate phototroph. The alga was unable to survive in continuous darkness even when cultures were supplemented with high concentrations of bacteria, and bacterivory ceased in cultures placed in the dark for a period longer than one day. Axenic growth of the alga was poor even in an optimal light regime. Live bacteria were required for sustained, vigorous growth of the alga in the light. Carbon (C), nitrogen (N), and phosphorus (P) budgets determined for the alga during growth in bacterized cultures indicated that bacterial biomass ingested by the alga may have contributed up to 25% of the organic carbon budget of the alga. Photosynthesis was the source of most (75%) of the organic carbon of the alga. D. cylindricum populations survived but did not grow when cultured in a continuous low light intensity (30 E m–2 sec–1), or in a light intensity of 150 E m–2 sec–1 for only two hours each day. Net efficiency of incorporation of bacterial C, N, and P into algal biomass under these two conditions was zero (i.e., no net algal population growth). We conclude that the primary function of bacterivorous behavior in D. cylindricum may be to provide essential growth factor(s) or major nutrients for photosynthetic growth, or to allow for the survival of individuals during periods of very low light intensity or short photoperiod.Offprint requests to: David A. Caron |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|