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Titel |
Release of hydrogen peroxide and antioxidants by the coral Stylophora pistillata to its external milieu |
VerfasserIn |
R. Armoza-Zvuloni, Y. Shaked |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 11, no. 17 ; Nr. 11, no. 17 (2014-09-01), S.4587-4598 |
Datensatznummer |
250117569
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Publikation (Nr.) |
copernicus.org/bg-11-4587-2014.pdf |
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Zusammenfassung |
Hydrogen peroxide (H2O2), a common reactive oxygen species, plays
multiple roles in coral health and disease. Elevated H2O2
production by the symbiotic algae during stress may result in symbiosis
breakdown and bleaching of the coral. We have recently reported that various
Red Sea corals release H2O2 and antioxidants to their external
milieu, and can influence the H2O2 dynamics in the reef.
Here, we present a laboratory characterization of H2O2 and
antioxidant activity release kinetics by intact, non-stressed
Stylophora pistillata. Experimenting with bleached and non-bleached
corals and different stirring speeds, we explored the sources and modes of
H2O2 and antioxidant release. Since H2O2 is produced and
degraded simultaneously, we developed a methodology for resolving the actual
H2O2 concentrations released by the corals.
H2O2 and antioxidant activity steadily increased in the water
surrounding the coral over short periods of 1–2 h. Over longer periods of
5–7 h, the antioxidant activity kept increasing with time, while
H2O2 concentrations were stabilized at ~ 1 μM by
1–3 h, and then gradually declined. Solving for H2O2 release,
corals were found to release H2O2 at increasing rates over 2–4 h,
and then to slow down and stop by 5–7 h. Stirring was shown to induce the
release of H2O2, possibly since the flow reduces the thickness of
the diffusive boundary layer of the coral, and thus increases H2O2
mass flux. Antioxidant activity was released at similar rates by bleached and
non-bleached corals, suggesting that the antioxidants did not originate from
the symbiotic algae. H2O2, however, was not released from bleached
corals, implying that the symbiotic algae are the source of the released
H2O2. The observed flow-induced H2O2 release may aid
corals in removing some of the internal H2O2 produced by their
symbiotic algae, and may possibly assist in preventing coral bleaching under
conditions of elevated temperature and irradiance. |
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