Obligate mixotrophy inLaboea strobila, a ciliate which retains chloroplasts

Stoecker, Diane K.; Silver, Mary W.; Michaels, Ann E.; Davis, Linda H.

doi:10.1007/bf02112135

Cited by 146 publications

(147 citation statements)

References 23 publications

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“…The prey Ceratium lineatum is a photosynthetic organism, and it was therefore necessary to separate predators from prey prior to photosynthesis measurements. Inspired by Rivkin & Seliger (1981) and Stoecker et al (1988), this was done by picking individual Fragilidium subglobosum cells with a drawn-out Pasteur pipette and rinsing each cell in Whatmann GF/F-filtered B-medium. The cells were then transferred to 20 ml capacity glass scintillation vials containing 2 ml freshly GF/F-filtered B-medium.…”

Section: Methodsmentioning

confidence: 99%

Physiology of the mixotrophic dinoflagellate Fragilidium subglobosum. I. Effects of phagotrophy and irradiance on photosynthesis and carbon content

Skovgaard¹,

Hansen²,

Stoecker³

2000

Mar. Ecol. Prog. Ser.

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Photosynthesis was measured for the mixotrophic dinoflagellate Fragilidium subglobosum grown with and without prey (Ceratium lineatum), at 5 different irradiances. Photosynthetic rates were measured in phototrophically and mixotrophically grown cultures by use of the single-cell 14 C uptake technique. Photosynthetic rates were reduced by 48 to 69% and cellular chlorophyll a (chl a) content was reduced by 13 to 67% in food-replete mixotrophic cultures as compared with strictly phototrophic cultures grown at the same irradiances. Under the same conditions, chl anormalized photosynthetic rates were thus 7 to 49% lower in mixotrophic cultures than in strictly phototrophic cultures. It is, therefore, suggested that either the photosynthetic apparatus becomes less efficient when the cells are phagotrophically active or the chl a-normalized photosynthesis is reduced because fed cells contain photosynthetically inactive chl a in their food vacuoles. When food is abundant, the greater part of the gross carbon uptake of F. subglobosum is acquired through phagotrophy even at irradiances saturating for photosynthesis.

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Section: Methodsmentioning

confidence: 99%

Physiology of the mixotrophic dinoflagellate Fragilidium subglobosum. I. Effects of phagotrophy and irradiance on photosynthesis and carbon content

Skovgaard¹,

Hansen²,

Stoecker³

2000

Mar. Ecol. Prog. Ser.

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“…Whether marine ciliates can synthesise long chain polyunsaturated fatty acids has not been established. However, it has been confirmed that some marine ciliates, particularly those of the genus Mesodiniurn, contain algal symbionts which can contribute significantly to the host organism's nutrition (Taylor 1982, Stoecker et al 1988, Wilkerson & Grunseich 1990) and they can contribute up to 20% of microplankton primary productivity in coastal waters (Stoecker 1991. It is also possible that the 22:6(n-3) associated with the ciliates is derived from their microplanktonic prey, particularly small flagellates and dinoflagellates (Azam et al 1983, Leakey et al 1992 as these organisms are known to be a rich source of 22:6(n-3) (Sargent et al 1995a, b).…”

Section: Microplanktonmentioning

confidence: 99%

Environmental and nutritional factors determining seasonal variability in the fecundity and egg viability of Calanus helgolandicus in coastal waters off Plymouth, UK

Pond¹,

Harris²,

Head³

et al. 1996

Mar. Ecol. Prog. Ser.

199

180

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Fecundity of the copepod Calanus helgolandicus was monitored at a coastal station in the western English Channel during January to September 1994 and varied seasonally from 3 to 33 eggs female-' d-l (mean 17 eggs female-' d-'). Particulate fatty acid levels, particularly in the <20 pm size fraction, were more highly correlated with fecundity than either chl a, particulate carbon or nitrogen. and this reflected the size and species composition of the microplankton. Diatoms, dinoflagellates and ciliates all sustained high fecundity. The mean volume of eggs produced by C. helgolandicus was inversely related to both food availability and fecundity, with increased numbers of smaller eggs produced during per~ods of high food availability. Female C helgolandicus with the highest body nitrogen and carbon produced eggs with the highest carbon and nltrogen contents, although these eggs were also smaller. Hatching viability was consistently high with a seasonal mean of 83% and both viability and the incidence of deformed nauplii were negatively correlated with the carbon and nitrogen content of females and eggs. Hatching viability was not correlated with the abundance of diatoms, but was closely correlated with the levels of 18:2(n-6) and 20:4(n-6) fatty acids in both the environment and in the eggs. Particulate concentrations of the polyunsaturated fatty acids 20:5(n-3) and 22:6(n-3), although abundant in the environment and therefore good indicators of food availability, were not correlated with either egg viability or naupliar survival. The levels of saturated and monounsaturated fatty acids in the eggs were important factors determining naupliar survival under starvation conditions. Although food availability limited fecundity, female recruitment was possibly limited by predation pressure. particularly during the late summer. This study highlights the value of seasonal and nutritional based studies in understanding variability in zooplankton fecundity.

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“…Here the plastids are placed at the periphery of the cell, probably for effectiveness in light-harvesting, and are often quite constant in number (Laval-Peuto 1992). The plastids have only a limited lifespan within the ciliate cell, before they are either diluted out, digested or egested (Stoecker et al 1988, Stoecker & Silver 1990. In many cases, it is not known whether the relationship is facultative or obligatory.…”

Section: Introductionmentioning

confidence: 99%

“…In many cases, it is not known whether the relationship is facultative or obligatory. Obligate mixotrophy has been demonstrated in only 1 chloroplast-retaining ciliate, Laboea strobila (Stoecker et al 1988).…”

Section: Introductionmentioning

confidence: 99%

Growth and grazing responses of two chloroplast-retaining dinoflagellates: effect of irradiance and prey species

Jakobsen¹,

Hansen²,

Larsen³

2000

Mar. Ecol. Prog. Ser.

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Obligate mixotrophy inLaboea strobila, a ciliate which retains chloroplasts

Cited by 146 publications

References 23 publications

Physiology of the mixotrophic dinoflagellate Fragilidium subglobosum. I. Effects of phagotrophy and irradiance on photosynthesis and carbon content

Physiology of the mixotrophic dinoflagellate Fragilidium subglobosum. I. Effects of phagotrophy and irradiance on photosynthesis and carbon content

Environmental and nutritional factors determining seasonal variability in the fecundity and egg viability of Calanus helgolandicus in coastal waters off Plymouth, UK

Growth and grazing responses of two chloroplast-retaining dinoflagellates: effect of irradiance and prey species

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