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Acclimation of a rocky shore algal reef builder Neogoniolithon sp. to changing illuminations
Author(s) -
GefenTreves Shany,
Kedem Isaac,
Weiss Gad,
Wagner Dirk,
Tchernov Dan,
Kaplan Aaron
Publication year - 2020
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.11245
Subject(s) - reef , thallus , crustose , coral reef , acclimatization , rocky shore , photosynthesis , algae , light intensity , ecology , chlorophyll fluorescence , oceanography , biology , botany , geology , intertidal zone , physics , optics
Vermetid reefs and rocky shores are hot spots of biodiversity, often referred to as the subtropical equivalent of coral reefs. The development of the ecosystem depends on the activity of several reef builders, including red crustose coralline algae (CCA) such as Neogoniolithon brassica‐florida . Despite its importance, little is known about Neogoniolithon sp. acclimation to rapid changes in light intensity and corresponding photosynthetic activity. To overcome the large spatial variability in the light field (due to location and the porous nature of the rocks) we grew Neogoniolithon sp. on glass slides and characterized its photosynthetic performance in response to various light intensities by following O 2 exchange and fluorescence parameters. This was also performed on rock‐inhabiting thalli collected from the east Mediterranean basin. Generally, maximal photosynthetic rate was reached when Neogoniolithon sp. thalli grown under low illumination (such as in protected niches where the light intensity can be as low as 1% of surface illumination) were examined. When exposed to light intensities higher than those experienced during growth, Neogoniolithon sp. activates adaptive/protective mechanisms such as state transition and nonphotochemical fluorescence quenching and increases the dark respiration thereafter. We find that the Fv/Fm parameter (variable/maximal fluorescence) is not suitable to assess photosynthetic performance in Neogoniolithon sp. and propose using instead an alternative parameter recently developed. Our findings help to clarify why Neogoniolithon sp. is usually observed in shaded niches along the reef surfaces.