Metabolic cost of calcification in bivalve larvae under experimental ocean acidification

Abstract Physiological increases in energy expenditure frequently occur in response to environmental stress. Although energy limitation is often invoked as a basis for decreased calcification under ocean acidification, energy-relevant measurements related to this process are scant. In this study we focus on first-shell (prodissoconch I) formation in larvae of the Pacific oyster, Crassostrea gigas. The energy cost of calcification was empirically derived to be ≤ 1.1 µJ (ng CaCO3)−1. Regardless of the saturation state of aragonite (2.77 vs. 0.77), larvae utilize the same amount of total energy to complete first-shell formation. Even though there was a 56% reduction of shell mass and an increase in dissolution at aragonite undersaturation, first-shell formation is not energy limited because sufficient endogenous reserves are available to meet metabolic demand. Further studies were undertaken on larvae from genetic crosses of pedigreed lines to test for variance in response to aragonite undersaturation. Larval families show variation in response to ocean acidification, with loss of shell size ranging from no effect to 28%. These differences show that resilience to ocean acidification may exist among genotypes. Combined studies of bioenergetics and genetics are promising approaches for understanding climate change impacts on marine organisms that undergo calcification.

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

Science Advances ◽

10.1126/sciadv.aba9958 ◽

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.

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Benthic buffers and boosters of ocean acidification on coral reefs

Biogeosciences ◽

10.5194/bg-10-4897-2013 ◽

2013 ◽

Vol 10 (7) ◽

pp. 4897-4909 ◽

Cited By ~ 45

Author(s):

K. R. N. Anthony ◽

G. Diaz-Pulido ◽

N. Verlinden ◽

B. Tilbrook ◽

A. J. Andersson

Keyword(s):

Ocean Acidification ◽

Benthic Communities ◽

Time Of Day ◽

High Flow ◽

Net Community Production ◽

Reef Environment ◽

Saturation State ◽

Low Co2 ◽

Coral Reef Environment ◽

Community Production

Abstract. Ocean acidification is a threat to marine ecosystems globally. In shallow-water systems, however, ocean acidification can be masked by benthic carbon fluxes, depending on community composition, seawater residence time, and the magnitude and balance of net community production (NCP) and calcification (NCC). Here, we examine how six benthic groups from a coral reef environment on Heron Reef (Great Barrier Reef, Australia) contribute to changes in the seawater aragonite saturation state (Ωa). Results of flume studies using intact reef habitats (1.2 m by 0.4 m), showed a hierarchy of responses across groups, depending on CO2 level, time of day and water flow. At low CO2 (350–450 μatm), macroalgae (Chnoospora implexa), turfs and sand elevated Ωa of the flume water by around 0.10 to 1.20 h−1 – normalised to contributions from 1 m2 of benthos to a 1 m deep water column. The rate of Ωa increase in these groups was doubled under acidification (560–700 μatm) and high flow (35 compared to 8 cm s−1). In contrast, branching corals (Acropora aspera) increased Ωa by 0.25 h−1 at ambient CO2 (350–450 μatm) during the day, but reduced Ωa under acidification and high flow. Nighttime changes in Ωa by corals were highly negative (0.6–0.8 h−1) and exacerbated by acidification. Calcifying macroalgae (Halimeda spp.) raised Ωa by day (by around 0.13 h−1), but lowered Ωa by a similar or higher amount at night. Analyses of carbon flux contributions from benthic communities with four different compositions to the reef water carbon chemistry across Heron Reef flat and lagoon indicated that the net lowering of Ωa by coral-dominated areas can to some extent be countered by long water-residence times in neighbouring areas dominated by turfs, macroalgae and carbonate sand.

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Assessing the Impacts of Ocean Acidification on Adhesion and Shell Formation in the Barnacle Amphibalanus amphitrite

Frontiers in Marine Science ◽

10.3389/fmars.2018.00369 ◽

2018 ◽

Vol 5 ◽

Cited By ~ 4

Author(s):

Jessica A. Nardone ◽

Shrey Patel ◽

Kyle R. Siegel ◽

Dana Tedesco ◽

Conall G. McNicholl ◽

...

Keyword(s):

Ocean Acidification ◽

Shell Formation

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Benthic buffers and boosters of ocean acidification on coral reefs

Biogeosciences Discussions ◽

10.5194/bgd-10-1831-2013 ◽

2013 ◽

Vol 10 (2) ◽

pp. 1831-1865 ◽

Cited By ~ 6

Author(s):

K. R. N. Anthony ◽

G. Diaz-Pulido ◽

N. Verlinden ◽

B. Tilbrook ◽

A. J. Andersson

Keyword(s):

Ocean Acidification ◽

Time Of Day ◽

High Flow ◽

Net Community Production ◽

Reef Environment ◽

Saturation State ◽

Low Co2 ◽

Coral Reef Environment ◽

Co2 Level ◽

Community Production

Abstract. Ocean acidification is a threat to marine ecosystems globally. In shallow-water systems, however, ocean acidification can be masked by benthic carbon fluxes, depending on community composition, seawater residence time, and the magnitude and balance of net community production (pn) and calcification (gn). Here, we examine how six benthic groups from a coral reef environment on Heron Reef (Great Barrier Reef, Australia) contribute to changes in seawater aragonite saturation state (Ωa). Results of flume studies showed a hierarchy of responses across groups, depending on CO2 level, time of day and water flow. At low CO2 (350–450 μatm), macroalgae (Chnoospora implexa), turfs and sand elevated Ωa of the flume water by around 0.10 to 1.20 h−1 – normalised to contributions from 1 m2 of benthos to a 1 m deep water column. The rate of Ωa increase in these groups was doubled under acidification (560–700 μatm) and high flow (35 compared to 8 cm s−1). In contrast, branching corals (Acropora aspera) increased Ωa by 0.25 h−1 at ambient CO2 (350–450 μatm) during the day, but reduced Ωa under acidification and high flow. Nighttime changes in Ωa by corals were highly negative (0.6–0.8 h−1) and exacerbated by acidification. Calcifying macroalgae (Halimeda spp.) raised Ωa by day (by around 0.13 h−1), but lowered Ωa by a similar or higher amount at night. Analyses of carbon flux contributions from four different benthic compositions to the reef water carbon chemistry across Heron Reef flat and lagoon indicated that the net lowering of Ωa by coral-dominated areas can to some extent be countered by long water residence times in neighbouring areas dominated by turfs, macroalgae and potentially sand.

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Quantifying the influence of CO<sub>2</sub> seasonality on future ocean acidification

Biogeosciences Discussions ◽

10.5194/bgd-12-5907-2015 ◽

2015 ◽

Vol 12 (8) ◽

pp. 5907-5940

Author(s):

T. P. Sasse ◽

B. I. McNeil ◽

R. J. Matear ◽

A. Lenton

Keyword(s):

Ocean Acidification ◽

North Pacific ◽

Dissolved Inorganic Carbon ◽

Marine Ecosystem ◽

Global Ocean ◽

Saturation State ◽

The North ◽

Data Limitations ◽

The Future ◽

The North Pacific

Abstract. Ocean acidification is a predictable consequence of rising atmospheric carbon dioxide (CO2), and is highly likely to impact the entire marine ecosystem – from plankton at the base to fish at the top. Factors which are expected to be impacted include reproductive health, organism growth and species composition and distribution. Predicting when critical threshold values will be reached is crucial for projecting the future health of marine ecosystems and for marine resources planning and management. The impacts of ocean acidification will be first felt at the seasonal scale, however our understanding how seasonal variability will influence rates of future ocean acidification remains poorly constrained due to current model and data limitations. To address this issue, we first quantified the seasonal cycle of aragonite saturation state utilizing new data-based estimates of global ocean surface dissolved inorganic carbon and alkalinity. This seasonality was then combined with earth system model projections under different emissions scenarios (RCPs 2.6, 4.5 and 8.5) to provide new insights into future aragonite under-saturation onset. Under a high emissions scenario (RCP 8.5), our results suggest accounting for seasonality will bring forward the initial onset of month-long under-saturation by 17 years compared to annual-mean estimates, with differences extending up to 35 ± 17 years in the North Pacific due to strong regional seasonality. Our results also show large-scale under-saturation once atmospheric CO2 reaches 486 ppm in the North Pacific and 511 ppm in the Southern Ocean independent of emission scenario. Our results suggest that accounting for seasonality is critical to projecting the future impacts of ocean acidification on the marine environment.

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Shell mineralogy of a foundational marine species, Mytilus californianus, over half a century in a changing ocean

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2004769118 ◽

2021 ◽

Vol 118 (3) ◽

pp. e2004769118

Author(s):

Elizabeth M. Bullard ◽

Ivan Torres ◽

Tianqi Ren ◽

Olivia A. Graeve ◽

Kaustuv Roy

Keyword(s):

Ocean Acidification ◽

Historical Data ◽

Mineralogical Composition ◽

Marine Species ◽

Mytilus Californianus ◽

Negative Effects ◽

Saturation State ◽

Long Term Changes ◽

Time Periods

Anthropogenic warming and ocean acidification are predicted to negatively affect marine calcifiers. While negative effects of these stressors on physiology and shell calcification have been documented in many species, their effects on shell mineralogical composition remains poorly known, especially over longer time periods. Here, we quantify changes in the shell mineralogy of a foundation species, Mytilus californianus, under 60 y of ocean warming and acidification. Using historical data as a baseline and a resampling of present-day populations, we document a substantial increase in shell calcite and decrease in aragonite. These results indicate that ocean pH and saturation state, not temperature or salinity, play a strong role in mediating the shell mineralogy of this species and reveal long-term changes in this trait under ocean acidification.

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Improvement of monodispersity and shape symmetry of silica shell for PbS quantum dots by introducing surface silanization and adjusting reverse micelle size

Japanese Journal of Applied Physics ◽

10.35848/1347-4065/ac3d19 ◽

2021 ◽

Author(s):

Kohki MUKAI ◽

Kosuke Ikeda ◽

Reo Hatta

Keyword(s):

Reverse Micelle ◽

Reverse Micelles ◽

Silica Coating ◽

Silica Shell ◽

Raw Material ◽

Shell Formation ◽

Shell Size ◽

Surface Control ◽

Micelle Size ◽

Pbs Quantum Dots

Abstract Increasing the thickness of the quantum dot silica coating layer reduces monodispersity and shape symmetry. This paper reports three effective ways to solve this problem and achieve a large silica-coated QDs, i.e., proper silanization on the QD surface, control of reverse micelle size by adjusting the amount of QD solvent, and two-step formation of silica shell. Proper substitution of ligands on the QD surface in the early stages of silica shell formation was important for uniform coating reaction. An amount of toluene as QD solvent determined the size of reverse micelles during the silica shell formation. There was an optimum combination of inverse micelle size and silica shell size to obtain silica-coated QDs with good monodispersity and high shape symmetry. We succeeded in growing the thick silica shell with expanding reverse micelle size by additionally supplying toluene with the raw material using the optimum silica-coated QDs as growth nucleus

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5. Climate change impacts

10.1093/actrade/9780198867869.003.0005 ◽

2021 ◽

pp. 64-89

Author(s):

Mark Maslin

Keyword(s):

Climate Change ◽

Health Policy ◽

Ocean Acidification ◽

Human Health ◽

Extreme Events ◽

Climate Change Impacts ◽

Climate Science ◽

Policy Makers ◽

Shifting Baseline ◽

Dangerous Climate Change

‘Climate change impacts’ assesses the potential impacts of climate change and how these alter in scale and intensity with increasing warming by breaking down the potential impacts into sectors: extreme heat and droughts, storms and floods, agriculture, ocean acidification, biodiversity, and human health. Policy-makers should identify what dangerous climate change is. We need a realistic target concerning the degree of climate change with which we can cope. Fortunately, the societal coping range is flexible and can change with the shifting baseline and the more frequent extreme events—as long as there is strong climate science to provide clear guidance on what sort of changes are going to occur.

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