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Abstract

The photosynthetic productivity of tropical microphytobenthos (MPB) is largely driven by changes in light intensities and temperature at the surface of sediment flats during emersion. Here, the response of the MPB community to temperature and light was examined. Changes in temperature and irradiance during tidal cycles in the Tanjung Rhu estuary, Langkawi, Malaysia, in 2007 significantly affected the photosynthetic capacities of the MPB. Higher photosynthetic parameters, such as the maximum relative electron transport rate (rETRmax), photosynthetic efficiency (α), maximum quantum yield (Fv/Fm), and effective quantum yield (ΔF/F′m), were recorded at high tide when the temperatures were lower. However, when the community was experimentally exposed to irradiances of 1800 µmol photons m−2 s−1, it was only able to photosynthesize at temperatures −3±0.002 s−1 and decreased to 1.01×10−5±0.001 s−1 at 60 ∘C, indicating irreversible damage to Photosystem II (PSII). These characteristics suggest that the MPB communities in this estuary were able to adapt to temperature variation. However, enhanced photoinhibition would result if exposed to elevated temperatures, especially during low tide where in situ temperature was already 43 ∘C. Hence, if in situ temperature were to further increase during tidal emersion, 50 ∘C could be a temperature threshold for photosynthetic performance of tropical estuarine benthic microalgal communities.

Item Type:	Article
Authors/Creators:	Salleh, S and McMinn, A
Keywords:	tropical marine diatom, MPB, temperature
Journal or Publication Title:	Biogeosciences
Publisher:	Copernicus GmbH
ISSN:	1726-4170
DOI / ID Number:	10.5194/bg-18-5313-2021
Copyright Information:	© Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 International (CC BY 4.0) License. (https://creativecommons.org/licenses/by/4.0/)
Related URLs:	Google Scholar: McMinn, A UTAS Profile: McMinn, A
Item Statistics:	View statistics for this item

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