The influence of UV radiation on number and ultrastructure of the endosymbiotic dinoflagellates in the sea anemoneCereus pedunculatus (Anthozoa: Actiniaria)

Hannack, K.; Kestler, P.; Sicken, O.; Westheide, Wilfried

doi:10.1007/bf02908729

Cited by 6 publications

(4 citation statements)

References 59 publications

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“…Such a response is generally evident within 10 d and involves loss of algae (Steen & Muscatine 1987, Hannack et al 1997. Assurance that the responses of the Montastraea franksi colonies transferred from the field to the high irradiance conditions of the laboratory wet bench were not confounded by a generalised stress response comes from the finding that the algal densities in colonies from different depths were maintained during acclimation for at least 14 d. Constant algal densities have also been observed in other studies of photoacclimation (Falkowski & Dubinsky 1981, Muller-Parker 1985, Harland & Davies 1994.…”

Section: Montastraea Franksimentioning

confidence: 57%

On the functional significance of molecular variation in Symbiodinium, the symbiotic algae of Cnidaria: photosynthetic response to irradiance

Savage¹,

Trapido-Rosenthal²,

Douglas³

2002

Mar. Ecol. Prog. Ser.

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The photosynthetic response to irradiance (PI response) of dinoflagellate algae of the genus Symbiodinium was quantified immediately after isolation from symbiosis with 9 species of corals and allied taxa on Bermuda. Significant variation in PI parameters was identified among the algal isolates, but no consistent differences between representatives of different Symbiodinium phylotypes were obtained. In a parallel analysis of Montastraea franksi, a dominant Bermudian coral species, colonies from 4 to 16 m (all bearing Symbiodinium of Phylotype B) were acclimated to high light conditions. The photoacclimatory response was slight. It included an increase in the dark respiration rate by algae from all collection depths, increased light use efficiency and decreased saturating irradiance of algae from 4 m, and increased maximal photosynthetic rate per unit chlorophyll (chl), but not per cell, for algae from 8 and 16 m. We conclude that generalisations about differences between the photosynthetic traits between Symbiodinium phylotypes are not valid, and that the wide depth distribution of M. franksi cannot be attributed to either depth-dependent association with multiple Symbiodinium phylotypes with different photosynthetic properties or strong photoacclimatory capabilities of its complement of Symbiodinium. These data suggest that Symbiodinium phylotype is not generally an important determinant of the abundance and distribution of symbioses on coral reefs. KEY WORDS: Symbiosis · Symbiodinium · Zooxanthellae · PI response · Molecular diversity Resale or republication not permitted without written consent of the publisher

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Section: Montastraea Franksimentioning

confidence: 57%

On the functional significance of molecular variation in Symbiodinium, the symbiotic algae of Cnidaria: photosynthetic response to irradiance

Savage¹,

Trapido-Rosenthal²,

Douglas³

2002

Mar. Ecol. Prog. Ser.

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“…their growth, mortality, symbioses, behaviour, population dynamics, metabolism and synthesis of UV-absorbing compounds. Ultraviolet light has been shown to be a signi¢cant potential stressor for these organisms; for instance, the bleaching phenomenon (in corals) is increasingly being ascribed in part to an action of ultraviolet (Gleason & Wellington, 1993;Shick et al, 1996;Hannack et al, 1997). Observations and previous laboratory experiments on UV e¡ects have been carried out over relatively short periods of time, a limitation which in itself constrains the speci¢c parameters that can be considered and excludes, for example, those associated with reproductive biology.…”

Section: Discussionmentioning

confidence: 99%

Influence of sublethal long-term UV irradiation on body mass, reproduction and behaviour of north European Actinia equina

et al. 1999

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Two strains of 6–8-y old Actinia equina (Anthozoa: Actiniaria) asexually derived from two individuals collected on the coast of Brittany were artificially UV irradiated in long-term experiments in the laboratory. After the animals had been allowed to adjust to the test aquaria for 15 months, a programme of UV irradiation and multiparameter analysis continued for 24 months. Ultraviolet irradiated sea anemones obtained in addition a quasi-solar UV irradiation at intensities representing the daily and annual cycles. Of the three modes of UV irradiation tested (1X, 2X and 4X), the one with the lowest intensity and duration (1X) corresponded approximately to the irradiation to which sea anemones are exposed in their natural habitat in the tidal zone of the southern North Sea. In all three modes all the actinians showed a similar, highly significant quasi-exponential weight loss immediately after the onset of UV irradiation. The more the animals were irradiated, the later juveniles were released from the gastrovascular cavity. At 2X the number of active animals gradually decreased after 18 months, whereas with the 4X irradiation mode the amount of activity fell abruptly and significantly after only eight months and remained at a very low level. Detachment from the substrate was also induced by UV irradiation. The experiments showed genotype-specific differences in body mass and migration. The crucial findings were that A. equina individuals that had adjusted to the laboratory for a long time did give clear responses to UV doses and intensities corresponding approximately to the irradiation in their natural intertidal environment or by radiation increased severalfold. The responses were immediate and sometimes irreversible to UV even in naturally occurring intensities and doses. The genotype specificity of some responses provides evidence that the stressor UV could induce genetic modifications of the population.

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“…So far individuals of five species have been studied for over 6 years in laboratory and semi-field experiments to assess the influence of UV radiation on a considerable number of parameters, and this work has been complemented by field observations (Hannack et al 1997;Westholt et al 1999). Of the many biological effects noted here, the only ones found to be irreversible over the entire duration of artificial UV radiation were the body mass reduction in one of the two investigated strains of Actinia equina (Westholt et al 1999) and three parameter changes in the white morph of Metridium senile.…”

Section: Introductionmentioning

confidence: 99%

Effects of long-term ultraviolet radiation: the white form of Metridium senile (Anthozoa: Actiniaria) as a potential biological indicator for ultraviolet

et al. 2001

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Genetically identical individuals of the white form of Metridium senile were kept in the laboratory for 40 months, during almost 2 years of which they were irradiated with ultraviolet (UV) radiation simulating the shape of the solar UV spectrum. The living and experimental conditions were largely matched to the conditions in the sea anemones' natural habitat on the North Sea coast. Controls were shielded from direct radiation or irradiated with only the visible range of the spectrum; for the UV tests, the UV component corresponded either to the conditions in the natural habitat or to twice or 4 times this dose. All experiments were preceded by a severalmonth settling-in period, and UV irradiation was always begun at a low intensity. Under these conditions UV was not lethal but produced many parameter changes, of which only those that were irreversible for the entire duration of the experiment, from September 1992 to August 1994, are described here. The body mass fell significantly in all three UV-radiation modes. All irradiated animals positioned themselves so as to be less exposed to the radiation, and all changed colour from white to brown. These responses are discussed with reference to the potential of M. senile as an indicator or monitor for UV in the northern European coastal region. Field analyses are currently being conducted to demonstrate the extent to which the present results apply to field conditions.

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The influence of UV radiation on number and ultrastructure of the endosymbiotic dinoflagellates in the sea anemoneCereus pedunculatus (Anthozoa: Actiniaria)

Abstract: The influence of UV radiation on number and ultrastructure of the endosymbiotic dinoflagellates in the sea anemone Cereus pedunculatus

Cited by 6 publications

References 59 publications

On the functional significance of molecular variation in Symbiodinium, the symbiotic algae of Cnidaria: photosynthetic response to irradiance

On the functional significance of molecular variation in Symbiodinium, the symbiotic algae of Cnidaria: photosynthetic response to irradiance

Influence of sublethal long-term UV irradiation on body mass, reproduction and behaviour of north European Actinia equina

Effects of long-term ultraviolet radiation: the white form of Metridium senile (Anthozoa: Actiniaria) as a potential biological indicator for ultraviolet

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