Photosynthetic activity estimated as in vivo chlorophyll a fluorescence in calcareous red macroalgae

Abstract

Photosynthetic activity was estimated, in 2 different sets of experiments, as in vivo chlorophyll a fluorescence in 2 calcareous red macroalgae: Neogoniolithon brassica-florida, which forms vermetid reefs with Dendropoma petraeum, and the rhodolith-forming Lithophyllum margaritae. In the first set of experiments, vermetid reefs collected from the Cabo de Gata-Níjar Natural Park (Almería, Spain) were incubated for 6 months in outdoor mesocosms at 2 different temperatures: ambient temperature (T) and ambient temperature plus 2 ºC (T+). Daily variations in effective quantum yields were related to the increase in solar radiation. Electron transport rate (ETR) was higher at T+ than at T. Oxygen production, estimated from ETR, was higher in N. brassica-florida growing in vermetid reefs in the coastal area than in those incubated in mesocosms or under laboratory conditions. In the second set of experiments, L. margaritae specimens with or without attached epifauna (mainly sponges) were collected at 2 sites (Pedregoso and CFE) on the Baja California Peninsula, Mexico, and at 2 depths (1 and 2 m). ETR values for rhodoliths collected at 1 m depth and with attached epifauna were higher than those for rhodoliths collected at 2 m depth, indicating the importance of greater incident radiation on photosynthetic activity. Photosynthetic activity was higher in L. margaritae collected from Pedregoso, the site with better water quality (high transparency and low pollution) and rocky substrate availability. In the CFE samples, the photosynthetic efficiency ( ETR) was highest in rhodoliths with attached epifauna. The highest ETR values for N. brassica-florida at T+ and the highest  ETR or ETR values for L. margaritae with attached sponges may be explained by the increase in CO 2 available for photosynthesis due to the respiration of the associated fauna. The usefulness of in vivo chlorophyll a fluorescence for estimating photosynthetic production in calcareous macroalgae under multifactorial experiments is discussed.

Primary production assessment on eco-engineering infrastructures: English Channel case study

“…The data were spectrally corrected and brown algae showed a high absorption at 474 nm with high efficiency for the major lightharvesting complex of photosystem II at this wavelength while red algae had a poor light transfer to PSII at this wavelength. The value of ETR are in accordance with literature [30] but calculation of this parameter is very heterogeneous in literature. Beside relative ETR (rETR) [31] measurements, calculation of ETR per unit surface as a function of time are conducted in different ways in literature [26,27,30,32].…”

“…The value of ETR are in accordance with literature [30] but calculation of this parameter is very heterogeneous in literature. Beside relative ETR (rETR) [31] measurements, calculation of ETR per unit surface as a function of time are conducted in different ways in literature [26,27,30,32]. The way how to calculate the absorption can change or a standard factor can be applied [32], FII can be considered as variable as a function of pigment groups ([17, 19, 20, 30] or constant for all groups [26,32].…”

Acclimation of a rocky shore algal reef builder Neogoniolithon sp. to changing illuminations

“…Crustose calcareous algae such as Neogoniolithon sp. inhabiting vermetid reefs are often exposed to harsh and stressing conditions, but despite their ecological importance, little is known about their responses to the ambient conditions and changes therein (Delphin et al ; Figueroa et al ; Cornwall et al ; Fine et al ). Likely, this is related to technical difficulties involved in the assessment of their performance, given the porous rocky habitat in the abrasion platforms.…”

“…Apparently, the organisms inhabiting the reef can cope with the harsh natural conditions including hydration–desiccation cycles in the intertidal zones, mechanical stress imposed by the waves, rapid pH shifts during photosynthesis and respiration, fluctuating light intensity, et al, but the mechanisms involved are poorly understood ( see Figueroa et al ; Cornwall et al ; Donald et al ; Fine et al ; Gomez‐Lemos and Diaz‐Pulido ; and references therein). Despite the importance of the CCAs, information on their acclimation to the large range of light intensities in their habitat, and changes therein, is scarce.…”

“…This was also the case in Neogoniolithon sp. (Campbell et al ; Baker ; Kalaji et al ; Figueroa et al ; Cornwall et al ; Fine et al ; Williamson et al ; and references therein). However, simultaneous fluorescence and O 2 evolution measurements performed on many organisms representing various groups showed an apparent "decoupling" between the two parameters, particularly under stressing conditions.…”