Carbon content, dark respiration and mortality of the mixotrophic planktonic ciliateStrombidium capitatum
✍ Scribed by D. W. Crawford; D. K. Stoecker
- Publisher
- Springer-Verlag
- Year
- 1996
- Tongue
- English
- Weight
- 891 KB
- Volume
- 126
- Category
- Article
- ISSN
- 0025-3162
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✦ Synopsis
Carbon content and rate of dark respiration was determined on individual Strombidium capitatum (Leegard) Kahl cells uniformly labelled with 1~C in culture. Isolated individuals were incubated in sterile medium in the dark for periods of up to 24 h, and cumulative respired 24CO 2 was retained in an alkaline trap. Cell carbon varied by more than an order of magnitude and followed a bi-modal distribution. "Small" cells of 2 to 7 ng C cell-1 respired at specific rates of ~ 3 to 5% cell C h-2, whereas "large" cells of 7 to 25 ng C cell-~ respired at ~ 1 to 2% cell C h-2. Mortality was greater for small cells than for large ones, and was greatest during the first few hours. Small cells accounted for 40% of all cells at initial time, To, whereas none of these survived a 16 h incubation. It is proposed that the rates of carbon-specific dark respiration observed for small cells compromise their ability to survive more than a few hours in the dark without food. The combination of influence of size (carbon content) together with differential proportions of small cells resulting from mortality contributed to considerable variance in carbon-specific respiration rates. When smaller and larger modal groups were considered separately, this variance was significantly reduced for both groups. Using this "refined" data, there was no significant starvation-induced reduction in carbon-specific Communicated by M. F.