scholarly journals Modelling coral polyp calcification in relation to ocean acidification

2012 ◽  
Vol 9 (11) ◽  
pp. 4441-4454 ◽  
Author(s):  
S. Hohn ◽  
A. Merico
Keyword(s):  
Ocean Acidification ◽  
Carbonate System ◽  
Co2 Diffusion ◽  
Coral Abundance ◽  
Coral Polyp ◽  
Polyp Tissue ◽  
Atmospheric Co2 Concentrations ◽  
The Impact ◽  
Fluid Diffusion ◽  
Seawater Pco2

Abstract. Rising atmospheric CO2 concentrations due to anthropogenic emissions induce changes in the carbonate chemistry of the oceans and, ultimately, a drop in ocean pH. This acidification process can harm calcifying organisms like coccolithophores, molluscs, echinoderms, and corals. It is expected that ocean acidification in combination with other anthropogenic stressors will cause a severe decline in coral abundance by the end of this century, with associated disastrous effects on reef ecosystems. Despite the growing importance of the topic, little progress has been made with respect to modelling the impact of acidification on coral calcification. Here we present a model for a coral polyp that simulates the carbonate system in four different compartments: the seawater, the polyp tissue, the coelenteron, and the calcifying fluid. Precipitation of calcium carbonate takes place in the metabolically controlled calcifying fluid beneath the polyp tissue. The model is adjusted to a state of activity as observed by direct microsensor measurements in the calcifying fluid. We find that a transport mechanism for bicarbonate is required to supplement carbon into the calcifying fluid because CO2 diffusion alone is not sufficient to sustain the observed calcification rates. Simulated CO2 perturbation experiments reveal decreasing calcification rates under elevated pCO2 despite the strong metabolic control of the calcifying fluid. Diffusion of CO2 through the tissue into the calcifying fluid increases with increasing seawater pCO2, leading to decreased aragonite saturation in the calcifying fluid. Our modelling study provides important insights into the complexity of the calcification process at the organism level and helps to quantify the effect of ocean acidification on corals.

scholarly journals Effects of seawater <i>p</i>CO<sub>2</sub> changes on the calcifying fluid of scleractinian corals

2012 ◽  
Vol 9 (3) ◽  
pp. 2655-2689 ◽  
Author(s):  
S. Hohn ◽  
A. Merico
Keyword(s):  
Anthropogenic Emissions ◽  
Carbonate System ◽  
Coral Abundance ◽  
Coral Polyp ◽  
Polyp Tissue ◽  
Calcification Process ◽  
Atmospheric Co2 Concentrations ◽  
The Impact ◽  
Fluid Diffusion ◽  
Seawater Pco2

Abstract. Rising atmospheric CO2 concentrations due to anthropogenic emissions induce changes in the ocean carbonate chemistry and a drop in ocean pH. This acidification process is expected to harm calcifying organisms like coccolithophores, molluscs, echinoderms, and corals. A severe decline in coral abundance is, for example, expected by the end of this century with associated disastrous effects on reef ecosystems. Despite the growing importance of the topic, little progress has been made with respect to modelling the impact of acidification on coral calcification. Here we present a model for a coral polyp that simulates the carbonate system in four different compartments: the seawater, the polyp tissue, the coelenteron, and the calicoblastic layer. Precipitation of calcium carbonate takes place in the metabolically controlled calicoblastic layer beneath the polyp tissue. The model is adjusted to a state of activity as observed by direct microsensor measurements in the calcifying fluid. Simulated CO2 perturbation experiments reveal decreasing calcification rates under elevated pCO2 despite strong metabolic control of the calcifying fluid. Diffusion of CO2 through the tissue into the calicoblastic layer increases with increasing seawater pCO2 leading to decreased aragonite saturation in the calcifying fluid of the coral polyp. Our modelling study provides important insights into the complexity of the calcification process at the organism level and helps to quantify the effect of ocean acidification on corals.

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.

scholarly journals Ocean Acidification Amplifies the Olfactory Response to 2-Phenylethylamine: Altered Cue Reception as a Mechanistic Pathway?

2021 ◽  
Author(s):  
Paula Schirrmacher ◽  
Christina C. Roggatz ◽  
David M. Benoit ◽  
Jörg D. Hardege
Keyword(s):  
Climate Change ◽  
Ocean Acidification ◽  
Hermit Crabs ◽  
Ecological Interactions ◽  
Ecological Processes ◽  
Mechanistic Pathway ◽  
Sea Lampreys ◽  
Pagurus Bernhardus ◽  
Decreasing Ph ◽  
The Impact

AbstractWith carbon dioxide (CO2) levels rising dramatically, climate change threatens marine environments. Due to increasing CO2 concentrations in the ocean, pH levels are expected to drop by 0.4 units by the end of the century. There is an urgent need to understand the impact of ocean acidification on chemical-ecological processes. To date, the extent and mechanisms by which the decreasing ocean pH influences chemical communication are unclear. Combining behaviour assays with computational chemistry, we explore the function of the predator related cue 2-phenylethylamine (PEA) for hermit crabs (Pagurus bernhardus) in current and end-of-the-century oceanic pH. Living in intertidal environments, hermit crabs face large pH fluctuations in their current habitat in addition to climate-change related ocean acidification. We demonstrate that the dietary predator cue PEA for mammals and sea lampreys is an attractant for hermit crabs, with the potency of the cue increasing with decreasing pH levels. In order to explain this increased potency, we assess changes to PEA’s conformational and charge-related properties as one potential mechanistic pathway. Using quantum chemical calculations validated by NMR spectroscopy, we characterise the different protonation states of PEA in water. We show how protonation of PEA could affect receptor-ligand binding, using a possible model receptor for PEA (human TAAR1). Investigating potential mechanisms of pH-dependent effects on olfactory perception of PEA and the respective behavioural response, our study advances the understanding of how ocean acidification interferes with the sense of smell and thereby might impact essential ecological interactions in marine ecosystems.

The impact of CO 2 -driven ocean acidification on early development and calcification in the sea urchin Strongylocentrotus intermedius

2016 ◽  
Vol 112 (1-2) ◽  
pp. 291-302 ◽  
Author(s):  
Yaoyao Zhan ◽  
Wanbin Hu ◽  
Weijie Zhang ◽  
Minbo Liu ◽  
Lizhu Duan ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Early Development ◽  
Sea Urchin ◽  
Strongylocentrotus Intermedius ◽  
The Impact

scholarly journals Ocean acidification and molluscan shell taphonomy: Can elevated seawater pCO2 influence taphonomy in a naticid predator–prey system?

2018 ◽  
Vol 507 ◽  
pp. 145-154 ◽  
Author(s):  
Jeff C. Clements ◽  
Michael R.S. Coffin ◽  
Romain Lavaud ◽  
Thomas Guyondet ◽  
Luc Comeau
Keyword(s):  
Ocean Acidification ◽  
Predator Prey ◽  
Prey System ◽  
Molluscan Shell ◽  
Seawater Pco2

scholarly journals A short history of ocean acidification science in the 20th century: a chemist's view

2013 ◽  
Vol 10 (11) ◽  
pp. 7411-7422 ◽  
Author(s):  
P. G. Brewer
Keyword(s):  
Ocean Acidification ◽  
20Th Century ◽  
Fossil Fuel ◽  
Trade Offs ◽  
History Of ◽  
Chemical Knowledge ◽  
The Creation ◽  
Ph Scale ◽  
The Impact

Abstract. This review covers the development of ocean acidification science, with an emphasis on the creation of ocean chemical knowledge, through the course of the 20th century. This begins with the creation of the pH scale by Sørensen in 1909 and ends with the widespread knowledge of the impact of the "High CO2 Ocean" by then well underway as the trajectory along the IPCC scenario pathways continues. By mid-century the massive role of the ocean in absorbing fossil fuel CO2 was known to specialists, but not appreciated by the greater scientific community. By the end of the century the trade-offs between the beneficial role of the ocean in absorbing some 90% of all heat created, and the accumulation of some 50% of all fossil fuel CO2 emitted, and the impacts on marine life were becoming more clear. This paper documents the evolution of knowledge throughout this period.

scholarly journals Heterogeneous CO<sub>2</sub> and CH<sub>4</sub> content of glacial meltwater from the Greenland Ice Sheet and implications for subglacial carbon processes

2021 ◽  
Vol 15 (3) ◽  
pp. 1627-1644
Author(s):  
Andrea J. Pain ◽  
Jonathan B. Martin ◽  
Ellen E. Martin ◽  
Åsa K. Rennermalm ◽  
Shaily Rahman
Keyword(s):  
Greenhouse Gas ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Mineral Weathering ◽  
Atmospheric Co2 ◽  
The Arctic ◽  
Co2 Concentrations ◽  
Geochemical Models ◽  
Atmospheric Co2 Concentrations ◽  
The Impact

Abstract. Accelerated melting of the Greenland Ice Sheet has increased freshwater delivery to the Arctic Ocean and amplified the need to understand the impact of Greenland Ice Sheet meltwater on Arctic greenhouse gas budgets. We evaluate subglacial discharge from the Greenland Ice Sheet for carbon dioxide (CO2) and methane (CH4) concentrations and δ13C values and use geochemical models to evaluate subglacial CH4 and CO2 sources and sinks. We compare discharge from southwest (a sub-catchment of the Isunnguata Glacier, sub-Isunnguata, and the Russell Glacier) and southern Greenland (Kiattut Sermiat). Meltwater CH4 concentrations vary by orders of magnitude between sites and are saturated with respect to atmospheric concentrations at Kiattut Sermiat. In contrast, meltwaters from southwest sites are supersaturated, even though oxidation reduces CH4 concentrations by up to 50 % during periods of low discharge. CO2 concentrations range from supersaturated at sub-Isunnguata to undersaturated at Kiattut Sermiat. CO2 is consumed by mineral weathering throughout the melt season at all sites; however, differences in the magnitude of subglacial CO2 sources result in meltwaters that are either sources or sinks of atmospheric CO2. At the sub-Isunnguata site, the predominant source of CO2 is organic matter (OM) remineralization. However, multiple or heterogeneous subglacial CO2 sources maintain atmospheric CO2 concentrations at Russell but not at Kiattut Sermiat, where CO2 is undersaturated. These results highlight a previously unrecognized degree of heterogeneity in greenhouse gas dynamics under the Greenland Ice Sheet. Future work should constrain the extent and controls of heterogeneity to improve our understanding of the impact of Greenland Ice Sheet melt on Arctic greenhouse gas budgets, as well as the role of continental ice sheets in greenhouse gas variations over glacial–interglacial timescales.

scholarly journals Assessing the impact of static and fluctuating ocean acidification on the behavior of Amphiprion percula

2021 ◽  
Author(s):  
Matthew A. Vaughan ◽  
Danielle L. Dixson
Keyword(s):  
Coral Reef ◽  
Ocean Acidification ◽  
Reef Fishes ◽  
Amphiprion Percula ◽  
Behavioral Abnormalities ◽  
Negative Impacts ◽  
Ground Truthing ◽  
Chemosensory Behavior ◽  
The Impact

AbstractCoral reef organisms are exposed to both an increasing magnitude of pCO2, and natural fluctuations on a diel scale. For coral reef fishes, one of the most profound effects of ocean acidification is the impact on ecologically important behaviors. Previous behavioral research has primarily been conducted under static pCO2 conditions and have recently come under criticism. Recent studies have provided evidence that the negative impacts on behavior may be reduced under more environmentally realistic, fluctuating conditions. We investigated the impact of both present and future day, static (500 and 1000 μatm) and diel fluctuating (500 ± 200 and 1000 ± 200 μatm) pCO2 on the lateralization and chemosensory behavior of juvenile anemonefish, Amphiprion percula. Our static experimental comparisons support previous findings that under elevated pCO2, fish become un-lateralized and lose the ability to discriminate olfactory cues. Diel-fluctuating pCO2 may aid in mitigating the severity of some behavioral abnormalities such as the chemosensory response, where a preference for predator cues was significantly reduced under a future diel-fluctuating pCO2 regime. This research aids in ground truthing earlier findings and contributes to our growing knowledge of the role of fluctuating conditions.

scholarly journals Variation in brachiopod microstructure and isotope geochemistry under low pH–ocean acidification–conditions

2018 ◽  
Author(s):  
Facheng Ye ◽  
Hana Jurikova ◽  
Lucia Angiolini ◽  
Uwe Brand ◽  
Gaia Crippa ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Ocean Acidification ◽  
Isotope Geochemistry ◽  
Shell Growth ◽  
Low Ph ◽  
Secondary Layer ◽  
Ph Conditions ◽  
One Year ◽  
The Impact ◽  
Δ13c And Δ18o

Abstract. Throughout the last few decades and in the near future CO2–induced ocean acidification is potentially a big threat to marine calcite-shelled animals (e.g., brachiopods, bivalves, corals and gastropods). Despite the great number of studies focusing on the effects of acidification on shell growth, metabolism, shell dissolution and shell repair, the consequences on biomineral formation remain poorly understood, and only few studies addressed contemporarily the impact of acidification on shell microstructure and geochemistry. In this study, a detailed microstructure and stable isotope geochemistry investigation was performed on nine adult brachiopod specimens of Magellania venosa (Dixon, 1789), grown in the natural environment as well as in controlled culturing experiments at different pH conditions (ranging 7.35 to 8.15 ± 0.05) over different time intervals (214 to 335 days). Details of shell microstructural features, such as thickness of the primary layer, density and size of endopunctae and morphology of the basic structural unit of the secondary layer were analysed using scanning electron microscopy (SEM). Stable isotope compositions (δ13C and δ18O) were tested from the secondary shell layer along shell ontogenetic increments in both dorsal and ventral valves. Based on our comprehensive dataset, we observed that, under low pH conditions, M. venosa produced a more organic-rich shell with higher density of and larger endopunctae, and smaller secondary layer fibres, when subjected to about one year of culturing. Also, increasingly negative δ13C and δ18O values are recorded by the shell produced during culturing and are related to the CO2–source in the culture setup. Both the microstructural changes and the stable isotope results are similar to observations on brachiopods from the fossil record and strongly support the value of brachiopods as robust archives of proxies for studying ocean acidification events in the geologic past.

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