Ocean Acidification Studies in Coral Reefs of Japan

2018 ◽  
pp. 63-70
Author(s):  
Shoji Yamamoto
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification

scholarly journals Experimental reef communities persist under future ocean acidification and warming

2021 ◽  
Author(s):  
Christopher Jury ◽  
Keisha Bahr ◽  
Evan Barba ◽  
Russell Brainard ◽  
Annick Cros ◽  
...  
Keyword(s):  
Experimental Study ◽  
Species Richness ◽  
Coral Reef ◽  
Coral Reefs ◽  
Ocean Acidification ◽  
Community Composition ◽  
Functional State ◽  
Reef Communities ◽  
Paris Climate Agreement

Abstract Coral reefs are among the most sensitive ecosystems affected by ocean acidification and warming, and are predicted to shift from net accreting calcifier-dominated systems to net eroding algal-dominated systems over the coming decades. Here we present a long-term experimental study examining the responses of entire mesocosm coral reef communities to acidification (-0.2 pH units), warming (+ 2°C), and combined future ocean (-0.2 pH, + 2°C) treatments. We show that under future ocean conditions, net calcification rates declined yet remained positive, corals showed reduced abundance yet were not extirpated, and community composition shifted while species richness was maintained. Our results suggest that under Paris Climate Agreement targets, coral reefs could persist in an altered functional state rather than collapse.

scholarly journals Sensitivity of Future Ocean Acidification to Carbon Climate Feedbacks

2017 ◽  
Author(s):  
Richard J. Matear ◽  
Andrew Lenton
Keyword(s):  
Surface Water ◽  
Coral Reefs ◽  
Ocean Acidification ◽  
Co2 Emissions ◽  
Atmospheric Co2 ◽  
Climate Feedbacks ◽  
The Future ◽  
Emissions Scenarios ◽  
Atmospheric Co2 Concentrations ◽  
The Impact

Abstract. Carbon-climate feedbacks have the potential to significantly impact the future climate by altering atmospheric CO2 concentrations (Zaehle et al., 2010). By modifying the future atmospheric CO2 concentrations, the carbon-climate feedbacks will also influence the future trajectory for ocean acidification. Here, we use the CO2 emissions scenarios from 4 Representative Concentration Pathways (RCPs) with an Earth System Model to project the future trajectories of ocean acidification with the inclusion of carbon-climate feedbacks. We show that simulated carbon-climate feedbacks can significantly impact the onset of under-saturated aragonite conditions in the Southern and Arctic Oceans, the suitable habitat for tropical coral and the deepwater saturation states. Under higher emission scenarios (RCP8.5 and RCP6.0), the carbon-climate feedbacks advance the onset of under-saturation conditions and the reduction in suitable coral reef habitat by a decade or more. The impact of the carbon-climate feedback is most significant for the medium (RCP4.5) and low emission (RCP2.6) scenarios. For RCP4.5 scenario by 2100, the carbon-climate feedbacks nearly double the area of surface water under-saturated respect to aragonite and reduce by 50 % the surface water suitable for coral reefs. For RCP2.6 scenario by 2100, the carbon-climate feedbacks reduce the area suitable for coral reefs by 40 % and increase the area of under-saturated surface water by 20 %. The high sensitivity of the impact of ocean acidification to the carbon-climate feedbacks in the low to medium emissions scenarios is important because our recent commitments to reduce CO2 emissions are trying to move us on to such an emissions scenario. The study highlights the need to better characterise the carbon-climate feedbacks to ensure we do not excessively stress the oceans by under-estimating the future impact of ocean acidification.

The coral reef-dwelling Peneroplis spp. shows calcification resilience to ocean acidification conditions - results from culture experiments

2021 ◽  
Author(s):  
Laurie Charrieau ◽  
Katsunori Kimoto ◽  
Delphine Dissard ◽  
Beatrice Below ◽  
Kazuhiko Fujita ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification ◽  
Sea Water ◽  
General Structure ◽  
Ion Concentration ◽  
Large Benthic Foraminifera ◽  
Carbonate Ion ◽  
Short Period

<p>Ocean acidification is a consequence of current anthropogenic climate changes. The concomitant decrease in pH and carbonate ion concentration in sea water may have severe impacts on calcifying organisms. Coral reefs are among the first ecosystems recognized vulnerable to ocean acidification. Within coral reefs, large benthic foraminifera (LBF) are major calcium carbonate producers.</p><p>The aim of this study was to evaluate the effects of varying pH on survival and calcification of the symbiont-bearing LBF species <em>Peneroplis</em> spp. We performed culture experiments to study their resistance to ocean acidification conditions, as well as their resilience once placed back under open ocean pH (7.9).</p><p>After three days, small signs of test decalcification were observed on specimens kept at pH 7.4, and severe test decalcification was observed on specimens kept at pH 6.9, with the inner organic lining clearly appearing. After 32 days under pH 7.4, similar strongly decalcified specimens were observed. All the specimens were alive at the end of the experiment. This result demonstrates the resistance of <em>Peneroplis </em>spp. to an acidified pH, at least on a short period of time.</p><p>After being partially decalcified, some of the living specimens were placed back at pH 7.9. After one month, the majority of the specimens showed recalcification features, mostly by addition of new chambers. The trace elements concentrations of the newly formed chambers were analysed by LA-ICPMS. Interestingly, more chambers were added when food was given, which highlights the crucial role of energy source in the recalcification process. Moreover, the newly formed chambers were most of the time abnormal, and the general structure of the tests was altered, with potential impacts on reproduction and in situ survival. In conclusion, if symbiont-bearing LBF show some resistance and resilience to lowered pH conditions, they will remain strongly affected by ocean acidification.</p>

scholarly journals THE ECONOMIC IMPACT OF OCEAN ACIDIFICATION ON CORAL REEFS

2012 ◽  
Vol 03 (01) ◽  
pp. 1250002 ◽  
Author(s):  
LUKE M. BRANDER ◽  
KATRIN REHDANZ ◽  
RICHARD S. J. TOL ◽  
PIETER J. H. VAN BEUKERING
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification ◽  
Economic Impact ◽  
Economic Value ◽  
Future Research ◽  
Atmospheric Concentration ◽  
Value Transfer ◽  
Rapid Economic Growth ◽  
Order Of Magnitude ◽  
Coral Reef Area

Because ocean acidification has only recently been recognized as a problem caused by CO2 emissions, impact studies are still rare and estimates of the economic impact are absent. This paper estimates the economic impact of ocean acidification on coral reefs which are generally considered to be economically as well as ecologically important ecosystems. First, we conduct an impact assessment in which atmospheric concentration of CO2 is linked to ocean acidity causing coral reef area loss. Next, a meta-analytic value transfer is applied to determine the economic value of coral reefs around the world. Finally, these two analyses are combined to estimate the economic impact of ocean acidification on coral reefs for the four IPCC marker scenarios. We find that the annual economic impact rapidly escalates over time, because the scenarios have rapid economic growth in the relevant countries and coral reefs are a luxury good. Nonetheless, the annual value in 2100 in still only a fraction of total income, one order of magnitude smaller than the previously estimated impact of climate change. Although the estimated impact is uncertain, the estimated confidence interval spans one order of magnitude only. Future research should seek to extend the estimates presented here to other impacts of ocean acidification and investigate the implications of our findings for climate policy.

scholarly journals Progressive seawater acidification on the Great Barrier Reef continental shelf

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Katharina E. Fabricius ◽  
Craig Neill ◽  
Erik Van Ooijen ◽  
Joy N. Smith ◽  
Bronte Tilbrook
Keyword(s):  
Coral Reefs ◽  
Continental Shelf ◽  
Great Barrier Reef ◽  
Ocean Acidification ◽  
Seawater Temperature ◽  
Barrier Reef ◽  
Saturation State ◽  
Seawater Acidification ◽  
Seawater Ph ◽  
Seawater Samples

Abstract Coral reefs are highly sensitive to ocean acidification due to rising atmospheric CO2 concentrations. We present 10 years of data (2009–2019) on the long-term trends and sources of variation in the carbon chemistry from two fixed stations in the Australian Great Barrier Reef. Data from the subtropical mid-shelf GBRWIS comprised 3-h instrument records, and those from the tropical coastal NRSYON were monthly seawater samples. Both stations recorded significant variation in seawater CO2 fugacity (fCO2), attributable to seasonal, daytime, temperature and salinity fluctuations. Superimposed over this variation, fCO2 progressively increased by > 2.0 ± 0.3 µatm year−1 at both stations. Seawater temperature and salinity also increased throughout the decade, whereas seawater pH and the saturation state of aragonite declined. The decadal upward fCO2 trend remained significant in temperature- and salinity-normalised data. Indeed, annual fCO2 minima are now higher than estimated fCO2 maxima in the early 1960s, with mean fCO2 now ~ 28% higher than 60 years ago. Our data indicate that carbonate dissolution from the seafloor is currently unable to buffer the Great Barrier Reef against ocean acidification. This is of great concern for the thousands of coral reefs and other diverse marine ecosystems located in this vast continental shelf system.

scholarly journals The other ocean acidification problem: CO 2 as a resource among competitors for ecosystem dominance

2013 ◽  
Vol 368 (1627) ◽  
pp. 20120442 ◽  
Author(s):  
Sean D. Connell ◽  
Kristy J. Kroeker ◽  
Katharina E. Fabricius ◽  
David I. Kline ◽  
Bayden D. Russell
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification ◽  
Atmospheric Carbon Dioxide ◽  
Environmental Changes ◽  
Kelp Forests ◽  
Direct Effects ◽  
Species Dominance ◽  
Tropical Conditions ◽  
Near Future

Predictions concerning the consequences of the oceanic uptake of increasing atmospheric carbon dioxide (CO 2 ) have been primarily occupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks direct and indirect effects of CO 2 on non-calcareous taxa that play critical roles in ecosystem shifts (e.g. competitors). We present the model that future atmospheric [CO 2 ] may act as a resource for mat-forming algae, a diverse and widespread group known to reduce the resilience of kelp forests and coral reefs. We test this hypothesis by combining laboratory and field CO 2 experiments and data from ‘natural’ volcanic CO 2 vents. We show that mats have enhanced productivity in experiments and more expansive covers in situ under projected near-future CO 2 conditions both in temperate and tropical conditions. The benefits of CO 2 are likely to vary among species of producers, potentially leading to shifts in species dominance in a high CO 2 world. We explore how ocean acidification combines with other environmental changes across a number of scales, and raise awareness of CO 2 as a resource whose change in availability could have wide-ranging community consequences beyond its direct effects.

scholarly journals Predicting the impact of ocean acidification on coral reefs: evaluating the assumptions involved

2015 ◽  
Vol 73 (3) ◽  
pp. 550-557 ◽  
Author(s):  
Paul L. Jokiel
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification ◽  
Bulk Water ◽  
Ion Concentration ◽  
Calcification Rate ◽  
Saturation State ◽  
Simplifying Assumptions ◽  
Reef Decline ◽  
Highly Correlated ◽  
The Impact

Abstract Predictions of future impact of climate change on coral reefs indicate that bleaching mortality due to higher temperature will be the major factor in the decline of coral reefs. Ocean acidification (OA) is increasingly considered to be an important contributing factor, but estimates of its importance vary widely in the literature. Models of future reef decline due to OA generally involve four simplifying assumptions that can lead to contradictions. The assumptions are: (i) Oceanic conditions of Ωarag control or are at least highly correlated with net calcification rate (Gnet) on coral reefs. (ii) Calcification rate is driven by bulk water carbonate ion concentration [CO32−] expressed as Ωarag. (iii) Changes in coral calcification rate can be used to estimate future changes in coral reef calcification rate. (iv) The impact of OA is additive and not synergistic with other environmental factors such as increased temperature. The assumption that aragonite saturation state (Ωarag) of seawater drives calcification is the most widely used and needs to be further evaluated. An alternate hypothesis is that calcification is limited by the ability of the system to rid itself of the protons generated by calcification. Recent studies allow further testing of the assumptions and point the way to resolving shortcomings in our understanding of how OA impacts coral reefs.

scholarly journals Coral Reefs and Ocean Acidification

Oceanography ◽  
2009 ◽  
Vol 22 (4) ◽  
pp. 108-117 ◽  
Author(s):  
Joan Kleypas ◽  
Kimberly Yates
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification
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