Response of foundation macrophytes to near-natural simulated marine heatwaves

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Non
Statut de publication : Publié
Année de publication : 2020
Auteurs (12) : SAHA Mahasweta BARBOZA Francisco,r SOMERFIELD Paul,j AL-JANABI Balsam BECK Miriam BRAKEL Janina ITO Maysa PANSCH Christian NASCIMENTO-SCHULZE Jennifer,c JAKOBSSON THOR Stina WEINBERGER Florian SAWALL Yvonne
Revue scientifique : Global Change Biology
Volume : 26
Fascicule : 2
Pages : 417-430
DOI : 10.1111/gcb.14801
URL : -
Abstract : Marine heatwaves have been observed worldwide and are expected to increase in both frequency and intensity due to climate change. Such events may cause ecosystem reconfigurations arising from species range contraction or redistribution, with ecological, economic and social implications. Macrophytes such as the brown seaweed Fucus vesiculosus and the seagrass Zostera marina are foundation species in many coastal ecosystems of the temperate northern hemisphere. Hence, their response to extreme events can potentially determine the fate of associated ecosystems. Macrophyte functioning is intimately linked to the maintenance of photosynthesis, growth and reproduction, and resistance against pathogens, epibionts and grazers. We investigated morphological, physiological, pathological and chemical defence responses of western Baltic Sea F. vesiculosus and Z. marina populations to simulated near-natural marine heatwaves. Along with (a) the control, which constituted no heatwave but natural stochastic temperature variability (0HW), two treatments were applied: (b) two late-spring heatwaves (June, July) followed by a summer heatwave (August; 3HW) and (c) a summer heatwave only (1HW). The 3HW treatment was applied to test whether preconditioning events can modulate the potential sensitivity to the summer heatwave. Despite the variety of responses measured in both species, only Z. marina growth was impaired by the accumulative heat stress imposed by the 3HW treatment. Photosynthetic rate, however, remained high after the last heatwave indicating potential for recovery. Only epibacterial abundance was significantly affected in F. vesiculosus. Hence both macrophytes, and in particular F. vesiculosus, seem to be fairly tolerant to short-term marine heatwaves at least at the intensities applied in this experiment (up to 5 degrees C above mean temperature over a period of 9 days). This may partly be due to the fact that F. vesiculosus grows in a highly variable environment, and may have a high phenotypic plasticity.
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Citation :
Saha M, Barboza FR, Somerfield PJ, Al-Janabi B, Beck M, Brakel J, Ito M, Pansch C, Nascimento-Schulze JC, Jakobsson Thor S, Weinberger F, Sawall Y (2020) Response of foundation macrophytes to near-natural simulated marine heatwaves. Global Change Biol 26: 417-430 | doi: 10.1111/gcb.14801