Production of CO2-tolerant microalgae have received much attention as well as physicochemical fixation of CO2 in industrial flue gas. Although many microalgae that are tolerant to high levels of CO2 have been found and evaluated, the CO2 concentration for their good growth is generally lower than their maximum tolerable CO2 level. In the present study, we attempted to isolate microalgae capable of growing in high levels of CO2 (high-level-CO2-preferring microalgae, HCP-microalgae). We used a CO2-permeable polystyrene bottle for the enrichment of HCP-microalgae in environmental samples.
Anthropogenic carbon dioxide (CO2) emissions simultaneously increase ocean temperatures and reduce ocean surface pH, a process termed ocean acidification (OA). OA is expected to negatively affect the growth and physiology of many calcified organisms, but the response of non-calcified (fleshy) organisms is less well understood. Rising temperatures and pCO2 can enhance photosynthetic rates (within tolerance limits). Therefore, warming may interact with OA to alter biological responses of macroalgae in complicated ways.
The effects of elevated CO2 and temperature on photosynthesis and calcification in the calcifying algae Halimeda macroloba and Halimeda cylindracea and the symbiont-bearing benthic foraminifera Marginopora vertebralis were investigated through exposure to a combination of four temperatures (28°C, 30°C, 32°C, and 34°C) and four CO2 levels (39, 61, 101, and 203 Pa; pH 8.1, 7.9, 7.7, and 7.4, respectively). Elevated CO2 caused a profound decline in photosynthetic efficiency (FV : FM), calcification, and growth in all species. After five weeks at 34°C under all CO2 levels, all species died.
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.
In this paper, we demonstrated that ocean acidification (OA) had significant negative effects on the microscopic development of Saccharina japonica in a short-term exposure experiment under a range of light conditions. Under elevated CO2, the alga showed a significant reduction in meiospore germination, fecundity, and reproductive success. Larger female and male gametophytes were noted to occur under high CO2 conditions and high light magnified these positive effects.
During mariculture period, maricultured macroalga Gracilaria lemaneiformis experienced seasonal temperature changes. In this study, we examine the effects of predicted ocean acidification on carbon and nitrogen accumulation and amino acids (AA) contents in G. lemaneiformis under different temperature levels. The results showed that G. lemaneiformis exhibited higher growth rates under high temperature conditions than under low temperature conditions, regardless of CO2 levels. Moreover, compared with low temperature, the culture conditions of high temperature enhanced N accumulation in G.
Human-induced ocean acidification and warming alter seawater carbonate chemistry reducing the calcification of reef-building crustose coralline algae (CCA), which has implications for reef stability. However, due to the presence of multiple carbonate minerals with different solubilities in seawater, the algal mineralogical responses to changes in carbonate chemistry are poorly understood. Here we demonstrate a 200% increase in dolomite concentration in living CCA under greenhouse conditions of high pCO2 (1,225 muatm) and warming (30 degrees C).
The absorption of anthropogenic CO2 by the oceans is causing a reduction in the pH of the surface waters termed ocean acidification (OA). This could have substantial effects on marine coastal environments where fleshy (non-calcareous) macroalgae are dominant primary producers and ecosystem engineers. Few OA studies have focused on the early life stages of large macroalgae such as kelps. This study evaluated the effects of seawater pH on the ontogenic development of meiospores of the native kelp Macrocystis pyrifera and the invasive kelp Undaria pinnatifida, in south-eastern New Zealand.
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.