|Nitzschia albicostalis: an apochloritic diatom worthy of ecological consideration|
Rogerson, A.; Hannah, F.J.; Wilson, P.C. (1993). Nitzschia albicostalis: an apochloritic diatom worthy of ecological consideration. Cah. Biol. Mar. 34(4): 513-522
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723, more
|Authors|| || Top |
- Rogerson, A.
- Hannah, F.J.
- Wilson, P.C.
The obligate heterotrophic diatom, Nitzschia albicostalis, was isolated from the surfaces of Fucus seratus between October 1991 and April 1992 but was not detected in samples taken between April and August (1992). This suggests that diatoms were only numerically significant over the winter months when they averaged 10.8 cells cm super(-2) of algal surface. Peak abundances, up to 35.4 cells cm super(-2) were noted in March. These apochloritic diatoms compete with bacteria for carbon and nutrients and consequently showed reduced growth rates and yields when cultured with bacteria. In the laboratory, the presence of bacteria stimulated diatoms to burrow down into agar and carrageenan, presumably through the localised release of diatom ectoenzymes. This tunnelling behaviour may be an adaptation to spatially separate competing microbial populations. Moreover, in some monoxenic cultures, the release by Nitzschia of a probable antimicrobial agent was noted. The ecological significance, and value of these laboratory observations is discussed.