Physiological response to warming in intertidal macroalgae with different thermal affinity

Díaz-Acosta, Laura; Barreiro, Rodolfo; Provera, Isabella; Piñeiro‐Corbeira, Cristina

doi:10.1016/j.marenvres.2021.105350

Cited by 2 publications

(1 citation statement)

References 30 publications

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“…The degree shift in the GPP from NP optimal temperature arise from the increase of respiration with temperatures without reaching a clear optimum (Collier et al, 2017;Piñeiro-Corbeira et al, 2018). The respiration rates we measured exponentially increased with the temperature as it was shown in other seaweed species (Piñeiro-Corbeira et al, 2018;Dıáz-acosta et al, 2021) and it could indicate a possible shift towards heterotrophic metabolism (Brown et al, 2004;Bennett et al, 2022b). Studies conducted on other representatives of the order Fucales showed marked signs of tissue necrosis at higher temperatures (Flukes et al, 2015;Graiff et al, 2015;Urrea-Victoria et al, 2020).…”

Section: Thermal Vulnerabilitysupporting

confidence: 61%

Thermal vulnerability of the Levantine endemic and endangered habitat-forming macroalga, Gongolaria rayssiae: implications for reef carbon

et al. 2022

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Ocean warming is a major threat to marine ecosystems, especially to species with a narrow thermal niche width and narrow biogeographic distribution, like some habitat-forming seaweeds. Declines of marine forests have been reported for several canopy-forming species in temperate regions, including the Mediterranean Sea, where they are dominated by species from the order Fucales, but most of the information on their ecology and status comes from the western basin. Here, we studied the thermal vulnerability and metabolic functioning of the endemic Gongolaria rayssiae located in fast-warming waters of the Israeli Mediterranean coast. We followed seasonal changes in phenology and ecology of G. rayssiae and its associated community during 2018-2020. Its highest biomass, density and thallus length were documented in spring-early summer (March-mid June). When seawater temperature exceeded 25°C, it shed its branches until February, when re-growth normally occurred. The thermal performance curve of G. rayssiae was determined by exposing it to 11 temperature levels in the range 15-35°C. The thermal optimum temperature for gross oxygen production, determined from the fitted curve, was 24.5°C. This relatively low thermal optimum suggests marked sensitivity to warming and supports the notion that G. rayssiae is a temperate relict species in the area. Additionally, we conducted seasonal ex-situ incubations during daytime and nighttime and recorded the highest primary productivity in spring, when it is at its peak of growth. In this season, its net inorganic carbon uptake was 42 ± 11 µmol C g dw-1 h-1 ( ± SD), while in its branchless form during late summer, it decreased six-fold. Due to the fast ocean warming conditions of the area, we hypothesize that the growth season of the species will shrink, and the species may eventually disappear. Finally, when exposed to high temperatures in natural and manipulative conditions, G. rayssiae exhibited a dramatic decline in its carbon sequestration rates with important implication for the carbon budget of the reef. This study highlights the importance of establishing a species phenology and environmental sensitivity (and especially that of endemic ones) in rapidly warming ecosystems, to estimate its potential fate due to climate change.

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Section: Thermal Vulnerabilitysupporting

confidence: 61%

Thermal vulnerability of the Levantine endemic and endangered habitat-forming macroalga, Gongolaria rayssiae: implications for reef carbon

et al. 2022

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The north–south divide? Macroalgal functional trait diversity and redundancy varies with intertidal aspect

Amstutz,

Firth,

Foggo

et al. 2023

Annals of Botany

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Background and Aims Marine macroalgae (‘seaweeds’) are critical to coastal ecosystem structure and function, but also vulnerable to the many environmental changes associated with Anthropogenic Climate Change (ACC). The local habitat conditions underpinning observed and predicted ACC-driven changes in intertidal macroalgal communities are complex and likely site-specific, in addition to more commonly reported regional factors like sea surface temperatures. Methods We examined how the composition and functional trait expression of macroalgal communities in SW England varied with aspect (i.e., north-south orientation) at four sites with opposing Equator- (EF) and Pole-facing (PF) surfaces. Previous work at these sites had established that average annual (low tide) temperatures vary by 1.6°C and that EF surfaces experience six-fold more frequent extremes (i.e., > 30°C). Key Results PF macroalgal communities were consistently more taxon rich; eleven taxa were unique to PF habitats, with only one restricted to EF. Likewise, functional richness and dispersion were greater on PF surfaces (dominated by algae with traits linked to rapid resource capture and utilization, but low desiccation tolerance), although differences in both taxon and functional richness were likely driven by the fact that less diverse EF-surfaces were dominated by desiccation-tolerant fucoids. Conclusions Although we cannot disentangle the influence of temperature variation on algal ecophysiology from the indirect effects of aspect on species interactions (niche pre-emption, competition, grazing etc), our study system provides an excellent model for understanding how environmental variation at local scales affects community composition and functioning. By virtue of enhanced taxonomic diversity, PF-aspects supported higher functional diversity, and consequently, greater effective functional redundancy. These differences may imbue PF-aspects with resilience against environmental perturbation, but if predicted increases in global temperatures are realised, some PF-sites may shift to a depauperate, desiccation-tolerant seaweed community with a concomitant loss of functional diversity and redundancy.

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Physiological response to warming in intertidal macroalgae with different thermal affinity

Cited by 2 publications

References 30 publications

Thermal vulnerability of the Levantine endemic and endangered habitat-forming macroalga, Gongolaria rayssiae: implications for reef carbon

Thermal vulnerability of the Levantine endemic and endangered habitat-forming macroalga, Gongolaria rayssiae: implications for reef carbon

The north–south divide? Macroalgal functional trait diversity and redundancy varies with intertidal aspect

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