Influence of local environmental conditions on the seasonal acclimation process and the daily integrated production rates of Laminaria digitata (Phaeophyta) in the English Channel

Abstract

International audienceTwo populations of Laminaria digitata (Hudson) Lamouroux (Ann Mus Hist Nat Paris 20:21-47, 1813) were examined for their seasonal photosynthetic acclimation to clear and turbid-light environments along the French coast of the English Channel. Photosynthesis-irradiance curves, pigment concentrations and the daily in situ integrated oxygen production rates were measured in both populations. Despite the great differences in light attenuation between the sites, the two populations achieved similar oxygen production rates in the field, in relation to high maximal photosynthetic rates, total pigment concentrations and antenna (fucoxanthin + chlorophyll c)/chl a pigment ratios in sporophytes from the turbid environment. Environmental conditions (i.e. light, temperature and nitrogen availability) changed throughout the year in both sites. While the seasonal acclimation trends were evident in the clear-light environment, the strategy in the turbid-light environment differed, tending to maximize light capture throughout the year. This study highlights the diversity of the response of a single species to contrasted light environments

The cultivation of European kelp for bioenergy: Site and species selection

“…Macroalgae grown in either high or low light environments employ different light use strategies to either reduce or increase the absorption of light to optimise their growth [126]. For example, this may be acclimation based on their phenotypic range, such as has been reported in L. digitata, or there may be adaptation resulting in light ecotypes, as has been found in S. latissima [127].…”

“…It is commonly only found down to 5 m [92], but can extend down to 40 m [32]. This species displays a high level of phenotypic plasticity allowing it to acclimate to this wide range of light conditions [126]. Growth of juvenile sporophytes is maximised at 20e30 mmol m À2 s À1 with photosynthesis apparatus saturated at 2e3 times this value [128].…”

Status, trends and drivers of kelp forests in Europe: an expert assessment

“…Other local factors reported to negatively affect kelp forest abundances are kelp harvesting (Christie et al 1998;Lorentsen et al 2010), decline of water quality (e.g. pollution, eutrophication, sedimentation) (Airoldi 2003;Delebecq et al 2013;Strain et al 2014), diseases and presence of non-native and invading species (Ellertsdóttir and Peters 1997;Williams and Smith 2007).…”

Morphology and photosynthetic response of the kelp Ecklonia radiata across a turbidity gradient

“…However, relatively little is known about how the morphology of E. radiata is influenced by variation in benthic irradiance, and how morphological variation is related to photoacclimation responses at a cellular and physiological level (but see Miller et al ; Rodgers et al ). In general, the effects of increased turbidity, and resulting low light environments, on individual kelp functioning are relatively unstudied (Gerard ; Delebecq et al ), yet are important to understanding how turbidity compromises overall reef productivity.…”