Irradiance, photosynthesis and elevated pCO2 effects on net calcification in tropical reef macroalgae

McNicholl, C.; Koch, Marguerite S.

doi:10.1016/j.jembe.2020.151489

Cited by 7 publications

(7 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The decline of CCA cover could also be due to the combined effect of decreased light exposure and high sedimentation. Indeed, under OA conditions, CCA growth significantly decreases under the combination of low light and low flow conditions (Comeau et al, 2019), and faces dissolution in shade environments (Martin et al, 2013;Bessell-Browne et al, 2017;McNicholl and Koch, 2021). Although light irradiance was not measured and sedimentation rates in the Bourakélagoon have yet to be comprehensively measured, it has been suggested that high turbidity in Bourakécould attenuate solar radiation (Jacquemont et al, 2022).…”

Section: Shift Between Cca and Turf Algaementioning

confidence: 99%

High Coral Recruitment Despite Coralline Algal Loss Under Extreme Environmental Conditions

et al. 2022

View full text Add to dashboard Cite

The crucial role of crustose coralline algae (CCA) in inducing hard coral larval settlement and ensuring the replenishment of coral reefs is widely accepted, and so are the negative effects of anthropogenic CO2 emissions on both CCA abundance and coral development. However, diversified and well-developed coral reef communities have been recently discovered in natural conditions where CCA and corals would not be expected to thrive. Back-reef pools, volcanic CO2 vents, mangrove estuaries, and semi-enclosed lagoons systems can present seawater pH, temperature, and dissolved oxygen values reaching or even exceeding the conditions currently predicted by the Inter Panel on Climate Change (IPCC) for 2100. In the semi-enclosed lagoon of Bouraké (New Caledonia, southwest Pacific Ocean), seawater pHT, dissolved oxygen, and temperatures regularly fluctuate with the tide reaching respectively minimum values of 7.23 pHT units, 2.28 mg O2 L-1, and maximum of 33.85°C. This study reports the effect of such extreme environmental conditions on hard coral recruitment and CCA originally settled at a forereef on artificial substrates that were transplanted over two years in two fringing reef and at the Bouraké lagoon. Our data emphasize the negative effects of the extreme conditions in our study sites on the CCA, which decreased in cover by ca. 80% and lost in the competition with turf algae, which, in turn, increased up to 162% at the end of the two years. Conversely, hard coral recruitment remained high at Bouraké throughout the study, three-fold higher than at two sites located outside Bouraké where environmental conditions were typical for coastal fringing reefs. Our findings show that while such extreme, climate change like-conditions have a direct and adverse effect on CCA abundance, and despite a certain persistence, coral larvae settlement was not affected. Based on previous findings from Bouraké, and the present observations, both coral recruits and adults seem to be unaffected despite the extreme environmental conditions. This study supports previous research illustrating how extreme natural and variable environments may reveal unexpected and positive insights on the processes underlying coral acclimatization and adaptation to global change.

show abstract

Section: Shift Between Cca and Turf Algaementioning

confidence: 99%

High Coral Recruitment Despite Coralline Algal Loss Under Extreme Environmental Conditions

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Beer and Larkum [64] suggested that calcification in Halimeda discoidea is linked to pH in intercellular spaces controlled by the ratio of photosynthesis to respiration. Recent studies have revealed that higher pH at the diffusive boundary layer in the light in many tropical calcified macroalgae, including Halimeda, is maintained by photosynthetic CCM involving a HCO 3 − -H + symport, OH − antiport and HCO 3 − dehydration catalyzed by external carbonic anhydrase [14,28]. Our study showed that approximately 4.5-4.7 mols of carbon were taken in photosynthesis for every mol carbon fixed into calcification in P. boryana.…”

Section: Discussionmentioning

confidence: 49%

“…Meanwhile, H. macroloba was the most sensitive species, displaying net dissolution after 1 h of darkness at the highest pH (7.74 ± 0.04) among all species. Minimal calcification and dissolution were also observed in species from genus Halimeda in the field condition at nighttime [13,14,75]. Differences in sensitivity to pH between H. opuntia and H. macroloba may be due to different morphological characteristics, such as branching and crystal microstructure [76].…”

Section: Discussionmentioning

confidence: 94%

“…Plants 2021, 10, 2537 2 of 18 Calcifying macroalgae are intriguing organisms and have become a subject of interest for recent marine frontiers research [12][13][14][15] as they are a source of primary production via photosynthesis as well as CaCO 3 production via calcification with relatively fast growth and turnover rates compared to corals [16,17]. However, their role in the carbon economy, whether they act as a net sink or source of carbon, remains a knowledge gap and debatable [18][19][20] mainly due to uncertainties about the fate of carbon associated with calcification.…”

Section: Introductionmentioning

confidence: 99%

“…Differential degrees of calcification and variation in microstructures are expected to be linked with their carbon use, particularly how they modify seawater chemistry and their carbon economy. In addition, the diversity of calcification sites and their proximity to pH-elevating processes (e.g., photosynthesis, H + pumping and carbon concentrating mechanisms (CCMs)) relative to external seawater might affect their response to changing environments [14,28,39,42,43].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calcification in Three Common Calcified Algae from Phuket, Thailand: Potential Relevance on Seawater Carbonate Chemistry and Link to Photosynthetic Process

Buapet

Sinutok

2021

Plants

View full text Add to dashboard Cite

Calcifying macroalgae contribute significantly to the structure and function of tropical marine ecosystems. Their calcification and photosynthetic processes are not well understood despite their critical role in marine carbon cycles and high vulnerability to environmental changes. This study aims to provide a better understanding of the macroalgal calcification process, focusing on its relevance concerning seawater carbonate chemistry and its relationship to photosynthesis in three dominant calcified macroalgae in Thailand, Padina boryana, Halimeda macroloba and Halimeda opuntia. Morphological and microstructural attributes of the three macroalgae were analyzed and subsequently linked to their calcification rates and responses to inhibition of photosynthesis. In the first experiment, seawater pH, total alkalinity and total dissolved inorganic carbon were measured after incubation of the macroalgae in the light and after equilibration of the seawater with air. Estimations of carbon uptake into photosynthesis and calcification and carbon release into air were obtained thereafter. Our results provide evidence that calcification of the three calcified macroalgae is a potential source of CO2, where calcification by H. opuntia and H. macroloba leads to a greater release of CO2 per biomass weight than P. boryana. Nevertheless, this capacity is expected to vary on a diurnal basis, as the second experiment indicates that calcification is highly coupled to photosynthetic activity. Lower pH as a result of inhibited photosynthesis under darkness imposes more negative effects on H. opuntia and H. macroloba than on P. boryana, implying that they are more sensitive to acidification. These effects were worsened when photosynthesis was inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea, highlighting the significance of photosynthetic electron transport-dependent processes. Our findings suggest that estimations of the amount of carbon stored in the vegetated marine ecosystems should account for macroalgal calcification as a potential carbon source while considering diurnal variations in photosynthesis and seawater pH in a natural setting.

show abstract

Systematic review and meta-analysis of ocean acidification effects in Halimeda: Implications for algal carbonate production

Schubert

Álvarez‐Filip

Hofmann

2023

Climate Change Ecology

View full text Add to dashboard Cite

Irradiance, photosynthesis and elevated pCO2 effects on net calcification in tropical reef macroalgae

Cited by 7 publications

References 68 publications

High Coral Recruitment Despite Coralline Algal Loss Under Extreme Environmental Conditions

High Coral Recruitment Despite Coralline Algal Loss Under Extreme Environmental Conditions

Calcification in Three Common Calcified Algae from Phuket, Thailand: Potential Relevance on Seawater Carbonate Chemistry and Link to Photosynthetic Process

Systematic review and meta-analysis of ocean acidification effects in Halimeda: Implications for algal carbonate production

Contact Info

Product

Resources

About