Intraspecific variations in responses to ocean acidification in two branching coral species

Sekizawa, Ayami; Uechi, Hikaru; Iguchi, Akira; Nakamura, Takashi; Kumagai, Naoki H.; Suzuki, Atsushi; Sakai, Kazuhiko; Nojiri, Yukihiro

doi:10.1016/j.marpolbul.2017.06.061

Cited by 19 publications

(11 citation statements)

References 42 publications

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“…• s −1 during the light periods. Although the light intensity in the experiment was much lower than that in the natural environment, we considered the light intensity to be acceptable in our experiment because the nubbins of the two species grew positively, as in previous similar experiments (Iguchi et al, 2012;Iguchi et al, 2014;Ohki et al, 2013;Kavousi et al, 2015;Sekizawa et al, 2017). The temperature and light intensity were manually measured every day using a thermometer (CT-450 WR; CUSTOM, Osaka, Japan) and quantum meter (QSL2100; Biospherical Instruments, Inc., San Diego, CA, USA).…”

Section: Ow Experimentsmentioning

confidence: 94%

Responses of branching reef corals Acropora digitifera and Montipora digitata to elevated temperature and pCO₂

Manullang

Millyaningrum

Iguchi

et al. 2020

PeerJ

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Anthropogenic emission of CO2 into the atmosphere has been increasing exponentially, causing ocean acidification (OA) and ocean warming (OW). The “business-as-usual” scenario predicts that the atmospheric concentration of CO2 may exceed 1,000 µatm and seawater temperature may increase by up to 3 °C by the end of the 21st century. Increases in OA and OW may negatively affect the growth and survival of reef corals. In the present study, we separately examined the effects of OW and OA on the corals Acropora digitifera and Montipora digitata, which are dominant coral species occurring along the Ryukyu Archipelago, Japan, at three temperatures (28 °C, 30 °C, and 32 °C) and following four pCO2 treatments (400, 600, 800, and 1,000 µatm) in aquarium experiments. In the OW experiment, the calcification rate (p = 0.02), endosymbiont density, and maximum photosynthetic efficiency (Fv/Fm) (both p < 0.0001) decreased significantly at the highest temperature (32 °C) compared to those at the lower temperatures (28 °C and 30 °C) in both species. In the OA experiment, the calcification rate decreased significantly as pCO2 increased (p < 0.0001), whereas endosymbiont density, chlorophyll content, and Fv/Fm were not affected. The calcification rate of A. digitifera showed greater decreases from 30 °C to 32 °C than that of M. digitata. The calcification of the two species responded differently to OW and OA. These results suggest that A. digitifera is more sensitive to OW than M. digitata, whereas M. digitata is more sensitive to OA. Thus, differences in the sensitivity of the two coral species to OW and OA might be attributed to differences in the endosymbiont species and high calcification rates, respectively.

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Section: Ow Experimentsmentioning

confidence: 94%

Responses of branching reef corals Acropora digitifera and Montipora digitata to elevated temperature and pCO₂

Manullang

Millyaningrum

Iguchi

et al. 2020

PeerJ

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“…Although some decreases in calcification rates in acidified seawater have been observed among coral species (Ries et al 2009;Comeau et al 2014;Iguchi et al 2014;Sekizawa et al 2017), some species are insensitive to acidified seawater under certain conditions (e.g., Holcomb et al 2010;Rodolfo-Metalpa et al 2010;Chauvin et al 2011;Ohki et al 2013;Takahashi and Kurihara 2013;Nakamura et al 2017). It is suggested that increased pCO 2 may facilitate the onset of photosynthesis by increasing HCO 3 − levels in acidified seawater (Marubini et al 2008;Comeau et al 2013).…”

Section: General Features Of the Response Of Coral To Ocean Acidificamentioning

confidence: 99%

Perspective on the response of marine calcifiers to global warming and ocean acidification—Behavior of corals and foraminifera in a high CO2 world “hot house”

Kawahata

Fujita

Iguchi

et al. 2019

Prog Earth Planet Sci

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The CO 2 concentration of air has increased over the last two centuries and recently surpassed 400 ppm. Carbon cycle models project CO 2 concentrations of 720 to 1000 ppm for the IPCC intermediate scenario (RCP 6.0), resulting in an increase in global mean temperature of~2.6°C and a decrease in seawater pH of~0.3. Together, global warming and ocean acidification are often referred to as the "evil twins" of climate change, potentially inducing severe threats in the near future. In this paper, our discussion is focused on the response of two major calcifiers, foraminifera and corals, which contribute much to the global carbonate burial rate. Photosymbiosis is regarded as an adaptive ecology for living in warm and oligotrophic oceans, especially for reef-building corals and larger reefdwelling benthic foraminifera. As a consequence of global warming, bleaching may be a global threat to algal symbiont-bearing marine calcifying organisms under conditions of high temperature and light intensity. If CO 2 is dissolved in seawater, the partial pressure of CO 2 in seawater (pCO 2) and dissolved inorganic carbon (DIC) increases while pH and the saturation state of carbonate minerals decreases without any change in total alkalinity. Generally, marine calcifying organisms show decreases in calcification rates in response to acidified seawater. However, the response often differs depending on situations, species, and life-cycle stage. Some benthic foraminifera showed a positive response to low pH conditions. The Acropora digitifera coral calcification of adult branches was not reduced markedly at higher pCO 2 conditions, although calcification tended to decrease versus pCO 2 in both aposymbiotic and symbiotic polyps. New analytical technologies help identify important constraints on calcification processes. Based upon Ca isotopes, the transport path of Ca 2+ and the degree of its activity would predominantly control the carbonate precipitation rate. Visualization of the extracellular pH distribution shows that proton pumping produces the high internal pH and large internal-external pH gap in association with foraminiferal calcification. From the perspective of a long-term change in the Earth's surface environment, foraminifera seem to be more adaptive and robust than corals in coping with ocean warming and acidification but it is necessary to further understand the mechanisms underlying variations in sensitivity to heat stress and acidified seawater for future prediction. Since CO 2 is more soluble in lower temperature seawater, ocean acidification is more critical in the polar and high-latitude

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“…We used the calcification rate of corals as an indicator of stress sensitivity, in accordance with previous studies (Davies, 1989;Anthony et al, 2008;Iguchi et al, 2012;Sekizawa et al, 2017). In the OW experiment, the calcification rate of both coral species showed the greatest decrease at the highest temperature (32 • C) compared to that at lower temperatures (Figs.…”

Section: Discussionmentioning

confidence: 87%

Supplemental Information 8: Photosynthetic efficiency (Fv/Fm) in the ocean warming treatment raw data

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Intraspecific variations in responses to ocean acidification in two branching coral species

Cited by 19 publications

References 42 publications

Responses of branching reef corals Acropora digitifera and Montipora digitata to elevated temperature and pCO₂

Responses of branching reef corals Acropora digitifera and Montipora digitata to elevated temperature and pCO₂

Perspective on the response of marine calcifiers to global warming and ocean acidification—Behavior of corals and foraminifera in a high CO2 world “hot house”

Supplemental Information 8: Photosynthetic efficiency (Fv/Fm) in the ocean warming treatment raw data

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Intraspecific variations in responses to ocean acidification in two branching coral species

Cited by 19 publications

References 42 publications

Responses of branching reef corals Acropora digitifera and Montipora digitata to elevated temperature and pCO2

Responses of branching reef corals Acropora digitifera and Montipora digitata to elevated temperature and pCO2

Perspective on the response of marine calcifiers to global warming and ocean acidification—Behavior of corals and foraminifera in a high CO2 world “hot house”

Supplemental Information 8: Photosynthetic efficiency (Fv/Fm) in the ocean warming treatment raw data

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Responses of branching reef corals Acropora digitifera and Montipora digitata to elevated temperature and pCO₂

Responses of branching reef corals Acropora digitifera and Montipora digitata to elevated temperature and pCO₂