The CO2-boosted trophic transfer from primary producers to herbivores has been increasingly discovered at natural CO2 vents and in laboratory experiments. Despite the emerging knowledge of this boosting effect, we do not know the extent to which it may be enhanced or dampened by ocean warming. We investigated whether ocean acidification and warming enhance the nutritional quality (C:N ratio) and energy content of turf algae, which is speculated to drive higher feeding rate, greater energy budget and eventually faster growth of herbivores.
Hizikia fusiforme (Harv.) Okamura (brown seaweed) was cultured using aeration with two CO2 conditions: outdoor air (actual atmospheric CO2 concentration, averaging 360 $μ$l l-1) and CO2-enriched air (averaging 700 $μ$l l-1), to investigate the possible adjustments of elevated atmospheric CO2 to the growth, photosynthesis and nitrogen metabolism in this mariculture species. Aeration with CO2-enriched air reduced the pH in the culture medium in comparison with aeration with air. The mean relative growth rate was enhanced when H. fusiforme was grown at high CO2 with respect to normal CO2.
Ulva spp., an increasingly important food, are the dominant species of the large-scale green tides. In this study, both the growth and the physiological responses of the Ulva prolifera were studied after cultured in three different light and dark regimes (12:12, 14:10 and 16:8-h light/dark) in combination with current (420 $μ$atm; LC) and increased (1000 $μ$atm; HC) levels of atmospheric CO2. Grown rate of U.