Migration or photoacclimation to prevent high irradiance and UV-B damage in marine microphytobenthic communities

Aquatic Microbial Ecology

Mireille Consalvey¹  Rupert Perkins¹  Sébastien Lefebvre¹  Jean-Luc Mouget¹ 

关键词: Microphytobenthos;    Migration;    Photodamage;    Photoinhibition;    Ultraviolet radiation;   

DOI  :  10.3354/ame01218

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Microphytobenthos (MPB) on intertidal mudflats is a major component of primary producers in some estuarine ecosystems. To sustain photosynthesis, MPB migrate through the upper sediment layer and form transient biofilms during emersion periods, and thus may be exposed to high irradiance and ultraviolet radiation (UV-R), possibly resulting in photodamage to the photosynthetic apparatus. In contrast, downard migration could allow cells to optimize position in the photic zone, avoiding photoinhibitory light levels. Engineered biofilms with inhibited migratory capacity were used to distinguish between possible strategies (photoacclimation or migration) evolved by MPB to cope with photoinhibitory irradiances, when a series of UV filters with different cut-off wavelengths was used to estimate the respective contribution of visible light and UV-R. Engineered biofilms with full migratory capacity maintained a high relative electron transport rate (rETR), in contrast to engineered non-migratory biofilms, which showed a decrease in rETR under high irradiance, with a greater decrease under UV-B radiation. Migration thus appeared to be the principal short-term mechanism allowing MPB to avoid or minimize UV-R and high PAR photodamage in situ. Nevertheless, physiological acclimation processes to different light levels (‘light-shade’ patterns) seem to occur in the long term, and probably superimpose on migratory capacity, making light history an important component of MPB photoacclimation strategies.

【 授权许可】

Unknown