Abstract
Acclimation of corals to light is known to rely on multiple strategies working at different timescales. Among them, photosynthetic alternative electron flows (AEFs) could act as photoprotective mechanisms under fluctuating light intensities. In this work, we first compared the use of AEFs in shallow and mesophotic colonies of the coral Stylophora pistillata by carrying out joint measurements of oxygen exchange and photosystems quantum yields. We observed similar capacities to re-route photosynthetically derived electrons toward oxygen (Mehler reaction) and to perform cyclic electron flow around photosystem I under high light intensity in both colony types. But in contrast to mesophotic colonies that hosted Cladocopium, the photosynthetic apparatus of Symbiodinium microadriaticum hosted by their shallow counterparts was notably able to drive a higher number of electrons, displayed a higher thermal dissipation of absorbed light energy. Then, a short-term light stress was applied to evaluate the plasticity of the photosynthetic apparatus. Both shallow and mesophotic colonies showed fast acclimation to the low light regime. In contrast, under the high light regime, mesophotic colonies showed a limited capacity to dissipate light energy and were strongly photoinhibited, though their PSI activity was partly preserved and likely involved cyclic electron flow. This study shows how important the photosynthetic alternative electron flows are in acclimation processes to light and how the plasticity of the photosynthetic processes in Symbiodiniaceae may shape the vertical distribution of the coral holobionts.
Original language | English |
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Pages (from-to) | 645-659 |
Number of pages | 15 |
Journal | Coral Reefs |
Volume | 42 |
Issue number | 3 |
DOIs | |
State | Published - Jun 2023 |
Bibliographical note
Publisher Copyright:© 2023, The Author(s), under exclusive licence to International Coral Reef Society (ICRS).
Funding
The European Union’s Horizon 2020 research and innovation program under grant agreement No 730984, ASSEMBLE Plus project (S.R.); the European Research Council (H2020-EU BEAL project No 682580) (P.C.); Belgian Fonds de la Recherche Scientifique F.R.S.-F.N.R.S. (PDR T.0032 (P.C.), and CDR J.0014.18 (JC.P.)). P.C. is Senior Research Associate from Fonds de la Recherche Scientifique—FNRS.
Funders | Funder number |
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Belgian Fonds de la Recherche Scientifique F.R.S.-F.N.R.S. | PDR T.0032, CDR J.0014.18 |
Horizon 2020 Framework Programme | 730984 |
European Commission | 682580 |
Keywords
- Cyclic electron flow
- Mehler reaction
- Mesophotic corals
- Non-photochemical quenching
- Photoacclimation
- Symbiodiniaceae