Metabolic activity of intertidal Fucus spp. communities: evidence for high aerial carbon fluxes displaying seasonal variability

Abstract

To cite this version:François Bordeyne, Aline Migné, Dominique Davoult. Metabolic activity of intertidal Fucus spp. communities: evidence for high aerial carbon fluxes displaying seasonal variability.

Variation of fucoid community metabolism during the tidal cycle: Insights from in situ measurements of seasonal carbon fluxes during emersion and immersion

“…To our knowledge, this study is the first one to investigate the in situ metabolism of an intertidal macroalgal community, during both emersion and immersion, and throughout the year. Results highlighted that the F. serratus community displayed, during both tidal periods, high rates of primary production and respiration that fluctuated throughout the year according to a seasonal pattern well‐established for such communities in temperate areas (e.g., Cheshire et al ; Golléty et al ; Bordeyne et al ). Accordingly, either when exposed to the air or immersed in seawater, the metabolism of this community was at its highest in summer, when both light availability and temperature were at their highest annual levels, and at its lowest in winter.…”

“…Emersion periods are thus essential for the organic carbon requirements of photosynthetic organisms, especially in winter when intertidal communities rapidly encounter a low‐light environment with the rising of the tide. Without these periods of air exposure, intertidal algae in temperate regions would completely drain their organic carbon stocks (Bordeyne et al ). Thus, while Maberly and Madsen () calculated that emersion periods can substantially contribute to the overall energy budget of a single species inhabiting high shore levels (i.e., Fucus spiralis ), our results support the idea that they can also substantially contribute to the energy budget of whole intertidal communities, even those spending most of their time underwater.…”

“…The CR : GCP ratio also showed a significant seasonal trend when calculated from measurements during emersion. The values of this ratio and its seasonal trend are in agreement with those previously observed for the same community (Bordeyne et al 2015), indicating that the underlying processes are highly conserved from year to year. The ratio between GCP and CR may thus depend on the combination of the seasonal fluctuations of two main elements: algal biomass and temperature.…”

“…This study falls in with previous investigations which have as common purpose to improve our understanding of the in situ metabolism of intertidal macroalgae communities (e.g., Goll ety et al 2008;Tait and Schiel 2011;Bordeyne et al 2015). For the first time, a comparison between aerial and underwater CR and GCP has been performed for such community.…”

“…Although intertidal macroalgal systems have been recognized as highly productive for several decades (Mann 1973), their metabolism has not been extensively studied to date. Only a few studies have investigated community metabolism in situ, but only either during emersion periods (e.g., Goll ety et al 2008;Bordeyne et al 2015) or during immersion (e.g., Tait and Schiel 2010), and there are no direct comparisons of aerial and underwater community metabolism (Mign e et al 2015a). However, such comparisons can provide insight into the relationship between environmental constraints and community metabolism (Pedersen et al 2013), and therefore into the functioning and dynamics of such communities.…”