The seaweed Gracilaria lemaneiformis is largely maricultivated in China, for use as food and as a material in the agar industry. This alga experiences ocean acidification caused by rising atmospheric CO2 levels, and experiences changing light levels caused by self-shading during the later period of mariculture. In this study, growth and amino acid (AA) content responses of G. lemaneiformis to different CO2 levels (the present and the predicted increased levels) and varying light levels at 28 (±1)°C temperature conditions were investigated. The results showed that a higher light level enhanced algal growth and decreased water loss, but reduced AA accumulation. Decreased pH levels (as a result of CO2 elevation) also enhanced algal growth and reduced AA contents, but the decreases in the AA score at the lower pH levels were not significant under the two light level treatments. In this study, the light treatments had greater influences on growth and AA contents than CO2 levels. The results suggest that G. lemaneiformis quality will be negatively affected during the later mariculture production period as levels of CO2 rise and global temperatures increase.
Chen B., Zou D., Zhu M. & Yang Y., in press. Effects of CO2 levels and light intensities on growth and amino acid contents in red seaweed Gracilaria lemaneiformis. Aquaculture Research. Article (subscription required).
