Marine heatwave duration and intensity interact to reduce physiological tipping points of kelp species with contrasting thermal affinities.
Ann Bot
; 133(1): 51-60, 2024 Mar 08.
Article
em En
| MEDLINE
| ID: mdl-37946547
ABSTRACT
BACKGROUND AND AIMS:
Marine heatwaves (MHWs) are widely recognized as pervasive drivers of ecosystem change, yet our understanding of how different MHW properties mediate ecological responses remains largely unexplored. Understanding MHW impacts on foundation species is particularly important, given their structural role in communities and ecosystems.METHODS:
We simulated a series of realistic MHWs with different levels of intensity (Control 14 °C, Moderate 18 °C, Extreme 22 °C) and duration (14 or 28 d) and examined responses of two habitat-forming kelp species in the southwest UK. Here, Laminaria digitata reaches its trailing edge and is undergoing a range contraction, whereas Laminaria ochroleuca reaches its leading edge and is undergoing a range expansion. KEYRESULTS:
For both species, sub-lethal stress responses induced by moderate-intensity MHWs were exacerbated by longer duration. Extreme-intensity MHWs caused dramatic declines in growth and photosynthetic performance, and elevated bleaching, which were again exacerbated by longer MHW duration. Stress responses were most pronounced in L. ochroleuca, where almost complete tissue necrosis was observed by the end of the long-duration MHW. This was unexpected given the greater thermal safety margins assumed with leading edge populations. It is likely that prolonged exposure to sub-lethal thermal stress exceeded a physiological tipping point for L. ochroleuca, presumably due to depletion of internal reserves.CONCLUSIONS:
Overall, our study showed that exposure to MHW profiles projected to occur in the region in the coming decades can have significant deleterious effects on foundation kelp species, regardless of their thermal affinities and location within respective latitudinal ranges, which would probably have consequences for entire communities and ecosystems.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Kelp
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Algas Comestíveis
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Laminaria
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article