Supplementary material to "Nutrients attenuate the negative effect of ocean acidification on reef coral calcification in the Arabian Sea upwelling zone (Masirah Island, Oman)"

2021 ◽  
Author(s):  
Philipp Michael Spreter ◽  
Markus Reuter ◽  
Regina Mertz-Kraus ◽  
Oliver Taylor ◽  
Thomas Christian Brachert
Keyword(s):  
Ocean Acidification ◽  
Arabian Sea ◽  
Reef Coral ◽  
Coral Calcification ◽  
Negative Effect ◽  
Supplementary Material ◽  
Arabian Sea Upwelling

scholarly journals Nutrients attenuate the negative effect of ocean acidification on reef coral calcification in the Arabian Sea upwelling zone (Masirah Island, Oman)

2021 ◽  
Author(s):  
Philipp Michael Spreter ◽  
Markus Reuter ◽  
Regina Mertz-Kraus ◽  
Oliver Taylor ◽  
Thomas Christian Brachert
Keyword(s):  
Ocean Acidification ◽  
Bulk Density ◽  
Arabian Sea ◽  
Reference Data ◽  
Reef Coral ◽  
Extension Rate ◽  
Data Set ◽  
Reef Corals ◽  
Negative Effect ◽  
Arabian Sea Upwelling

Abstract. Tropical shallow-water reefs are the most diverse ecosystem in the ocean. Its persistence rests upon adequate calcification rates of the reef building biota, such as reef corals. Optimum calcification rates of reef corals occur in oligotrophic environments with high seawater saturation states of aragonite (Ωsw), which leads to increased vulnerability to anthropogenic ocean acidification and eutrophication. The calcification response of reef corals to this changing environment is largely unknown, however. Here, we present annually and sub-annually resolved records of calcification rates (n = 3) of the coral Porites from the nutrient rich and low Ωsw Arabian Sea upwelling zone (Masirah Island, Oman). Calcification rates were determined from the product of skeletal extension and bulk density derived from X-ray densitometry. Compared to a reference data set of coral skeletons from typical reef environments (Great Barrier Reef, Hawaii), mean annual skeletal bulk density of Porites from Masirah Island is reduced by 28 %. This density deficit prevails over the entire year and probably reflects a year-round low saturation state of aragonite at the site of calcification (Ωcf), independent of seasonal variations in Ωsw (e.g. upwelling). Mean annual extension rate is 20 % higher than for the reference data set. In particular, extension rate is strongly enhanced during the seasons with the lowest water temperatures, presumably due to a high PO43−/NO3−-ratio promoting rapid upward growth of the skeleton. Enhanced annual extension attenuates the negative effect of low density on calcification rate from −25 % to −11 %, while sub-annual calcification rates during the cool seasons even exceed those of the reference corals. We anticipate optimal nutrient environments (e.g. high PO43−/NO3−-ratios) to have significant potential to compensate the negative effect of ocean acidification on reef coral calcification, thereby allowing to maintain adequate rates of carbonate accumulation, which are essential for preserving this unique ecosystem.

Variability, trend and controlling factors of Ocean acidification over Western Arabian Sea upwelling region

2019 ◽  
Vol 209 ◽  
pp. 14-24 ◽  
Author(s):  
Mohanan Geethalekshmi Sreeush ◽  
Saran Rajendran ◽  
Vinu Valsala ◽  
Sreenivas Pentakota ◽  
K.V.S.R. Prasad ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Arabian Sea ◽  
Controlling Factors ◽  
Arabian Sea Upwelling

scholarly journals Evolution of the Arabian Sea Upwelling from the Last Millennium to the Future as Simulated by Earth System Models

Climate ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 72
Author(s):  
Xing Yi ◽  
Birgit Hünicke ◽  
Eduardo Zorita
Keyword(s):  
Arabian Sea ◽  
Positive Trend ◽  
Last Millennium ◽  
Earth System ◽  
System Models ◽  
Sediment Records ◽  
The Future ◽  
Water Stratification ◽  
Arabian Sea Upwelling ◽  
Earth System Models

Arabian Sea upwelling in the past has been generally studied based on the sediment records. We apply two earth system models and analyze the simulated water vertical velocity to investigate coastal upwelling in the western Arabian Sea over the last millennium. In addition, two models with slightly different configurations are also employed to study the upwelling in the 21st century under the strongest and the weakest greenhouse gas emission scenarios. With a negative long-term trend caused by the orbital forcing of the models, the upwelling over the last millennium is found to be closely correlated with the sea surface temperature, the Indian summer Monsoon and the sediment records. The future upwelling under the Representative Concentration Pathway (RCP) 8.5 scenario reveals a negative trend, in contrast with the positive trend displayed by the upwelling favorable along-shore winds. Therefore, it is likely that other factors, like water stratification in the upper ocean layers caused by the stronger surface warming, overrides the effect from the upwelling favorable wind. No significant trend is found for the upwelling under the RCP2.6 scenario, which is likely due to a compensation between the opposing effects of the increase in upwelling favorable winds and the water stratification.

scholarly journals Thermal stress reduces pocilloporid coral resilience to ocean acidification by impairing control over calcifying fluid chemistry

2021 ◽  
Vol 7 (2) ◽  
pp. eaba9958
Author(s):  
Maxence Guillermic ◽  
Louise P. Cameron ◽  
Ilian De Corte ◽  
Sambuddha Misra ◽  
Jelle Bijma ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Ocean Acidification ◽  
Pocillopora Damicornis ◽  
Carbonate Chemistry ◽  
Negative Interaction ◽  
Saturation State ◽  
Stylophora Pistillata ◽  
Coral Calcification ◽  
Influence Of Temperature On ◽  
Different Time Scales

The combination of thermal stress and ocean acidification (OA) can more negatively affect coral calcification than an individual stressors, but the mechanism behind this interaction is unknown. We used two independent methods (microelectrode and boron geochemistry) to measure calcifying fluid pH (pHcf) and carbonate chemistry of the corals Pocillopora damicornis and Stylophora pistillata grown under various temperature and pCO2 conditions. Although these approaches demonstrate that they record pHcf over different time scales, they reveal that both species can cope with OA under optimal temperatures (28°C) by elevating pHcf and aragonite saturation state (Ωcf) in support of calcification. At 31°C, neither species elevated these parameters as they did at 28°C and, likewise, could not maintain substantially positive calcification rates under any pH treatment. These results reveal a previously uncharacterized influence of temperature on coral pHcf regulation—the apparent mechanism behind the negative interaction between thermal stress and OA on coral calcification.

scholarly journals Supplementary material to "Overcalcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high CO<sub>2</sub> waters are not pre-adapted to ocean acidification"

2017 ◽  
Author(s):  
Peter von Dassow ◽  
Francisco Díaz-Rosas ◽  
El Mahdi Bendif ◽  
Juan-Diego Gaitán-Espitia ◽  
Daniella Mella-Flores ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Emiliania Huxleyi ◽  
Supplementary Material

scholarly journals Reviews and Syntheses: Responses of coccolithophores to ocean acidification: a meta-analysis

2015 ◽  
Vol 12 (6) ◽  
pp. 1671-1682 ◽  
Author(s):  
J. Meyer ◽  
U. Riebesell
Keyword(s):  
Ocean Acidification ◽  
Dissolved Inorganic Carbon ◽  
Meta Analysis ◽  
Physiological Responses ◽  
Total Alkalinity ◽  
Adaptive Responses ◽  
Negative Effects ◽  
Ecological Fitness ◽  
Negative Effect ◽  
Gephyrocapsa Oceanica

Abstract. Concerning their sensitivity to ocean acidification, coccolithophores, a group of calcifying single-celled phytoplankton, are one of the best-studied groups of marine organisms. However, in spite of the large number of studies investigating coccolithophore physiological responses to ocean acidification, uncertainties still remain due to variable and partly contradictory results. In the present study we have used all existing data in a meta-analysis to estimate the effect size of future pCO2 changes on the rates of calcification and photosynthesis and the ratio of particulate inorganic to organic carbon (PIC / POC) in different coccolithophore species. Our results indicate that ocean acidification has a negative effect on calcification and the cellular PIC / POC ratio in the two most abundant coccolithophore species: Emiliania huxleyi and Gephyrocapsa oceanica. In contrast, the more heavily calcified species Coccolithus braarudii did not show a distinct response when exposed to elevated pCO2/reduced pH. Photosynthesis in Gephyrocapsa oceanica was positively affected by high CO2, while no effect was observed for the other coccolithophore species. There was no indication that the method of carbonate chemistry manipulation was responsible for the inconsistent results regarding observed responses in calcification and the PIC / POC ratio. The perturbation method, however, appears to affect photosynthesis, as responses varied significantly between total alkalinity (TA) and dissolved inorganic carbon (DIC) manipulations. These results emphasize that coccolithophore species respond differently to ocean acidification, both in terms of calcification and photosynthesis. Where negative effects occur, they become evident at CO2 levels in the range projected for this century in the case of unabated CO2 emissions. As the data sets used in this meta-analysis do not account for adaptive responses, ecological fitness and ecosystem interactions, the question remains as to how these physiological responses play out in the natural environment.

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