Effects of photoperiod and light spectra on growth and pigment composition of the green macroalga Codium tomentosum

Rúben Marques,Rui Pereira,Paulo Cartaxana,Helena Abreu,Bárbara Pitarma,Sónia Cruz,Ana Lillebø,Ricardo Calado,Jorge Marques Da Silva

doi:10.1007/s10811-020-02289-9

Rúben Marques, Rui Pereira + Show 7 more

Open Access

https://doi.org/10.1007/s10811-020-02289-9

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Abstract

Codium tomentosum is a marine green macroalga with multiple value-added applications that is being successfully used as an extractive species in sustainable integrated multi-trophic aquaculture systems. Nonetheless, growth conditions of this species at an early development phase still require optimization. The present study addresses, under controlled laboratory conditions, the effects of photoperiod (long vs. short-day) and light spectra (white, blue, and red light) on growth and pigment composition of C. tomentosum. Relative growth rate was approximately 2× higher under long-day photoperiod (average of 39.2 and 20.1% week−1 for long and short-day, respectively). Concentrations per dry weight of major pigments such as chlorophyll a (Chla) and siphonoxanthin (Siph) were significantly higher under long-day photoperiod. Relative growth rates were higher under red light, intermediate under white light, and lower under blue light. These last results were rather surprising, as Siph-Chla/Chlb light harvesting complexes of Codium have increased absorption in the blue-green region of the light spectra. Changes in carbon allocation patterns caused by the spectral composition of light and overgrowth of green microalgae in blue light cultures could explain the differences recorded for relative growth rate. Long-day photoperiod and light sources with preferential emission at the red region of the light spectra were identified as optimal for growth of C. tomentosum at early development stages. These lighting conditions can reduce the time required to reach the necessary biomass before transfer to grow-out systems. Overall, these findings can shorten production time, increase macroalgal productivity, and enhance aquaculture revenues.

Highlights

Environmental concerns related to traditional fish aquaculture practices include oxygen depletion, eutrophication, and algal blooms, resulting from nutrient-enriched effluent discharges to adjacent aquatic environments (Pillay 2004)
The relative growth rate (RGR) of C. tomentosum under long-day (16 h light:8 h dark; LD) photoperiod was significantly higher (F1,8 = 129.8, p < 0.001) than that recorded under short-day (8 h light:16 h dark; SD) conditions (Fig. 2)
Along the 5-week growth period, C. tomentosum cultures growth rates decreased from week 1 to week 3, but the Relative growth rate (RGR) values leveled on week 4 and 5

Summary

Introduction

Environmental concerns related to traditional fish aquaculture practices include oxygen depletion, eutrophication, and algal blooms, resulting from nutrient-enriched effluent discharges to adjacent aquatic environments (Pillay 2004). ECOMARE, CESAM, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal. Present address: A4F Algae for Future, Estrada do Paço do Lumiar, Campus do Lumiar, Edif. BioISI and Department of Plant Biology, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal multi-trophic aquaculture (IMTA) approaches have emerged, as these include extractive species from different trophic levels to uptake available nutrients in effluent waters. This practice is perceived as more environmentally friendly and economically sustainable (Granada et al 2016). Macroalgae are important natural resources explored for a variety of purposes, mainly as food and feed, and as biofuels, biostimulants, and cosmetics (Samaraweera et al 2011; Abreu et al 2014; Santos et al 2015)

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