Count down the days until the New Year with the OA-ICC!

Each day of December you will find a short story on the OA-ICC news stream, highlighting an ocean acidification project or effort, demystifying a strange ocean acidification acronym or reminding you of a useful ocean acidification resource!

Look out for the OA-ICC December calendar – coming up December 1st!

Ocean acidification reshapes the otolith-body allometry of growth in juvenile sea bream

The effects of elevated CO2 partial pressure (pCO2) on otolith calcification and on the coupling between somatic and otolith growth were investigated in juvenile gilthead sea bream Sparus aurata. Six-month old individuals were raised during seven weeks under four pCO2 conditions set according to projected future ocean acidification scenarios. Body and otolith biometric parameters were measured throughout the experiment along with the otolith biomineralization monitored using a radiotracer technique based on 45Ca incorporation. Sea bream exhibited somatic growth resilience to all treatments. In contrast, increased growth rate and shape complexity of otoliths were observed with a pHT drop from 8.1 to 7.5. Hypercalcification was observed under lowered pH, with a rate of calcium incorporation increasing by up to 18% between pHT 8.1 and pHT 7.7. This work highlighted an uncoupling of otolith and body growth of juvenile sea bream within 40 days at pHT 7.9 projected to be reached by the end of the century. As the otolith is an essential tool used in reconstructing fish life history, this work suggests that information resulting from otolith studies should be interpreted with caution with respect to the potential impacts that ocean acidification projected modifications could have on otolith biomineralization.

Continue reading ‘Ocean acidification reshapes the otolith-body allometry of growth in juvenile sea bream’

The pH is falling! Oysters and economics on the Hill

That’s right – the pH is falling. The pH of our oceans to be exact.

Yesterday afternoon, WWF-Canada and the All Party Ocean Caucus hosted an Oceans on the Hill event to highlight this global issue, which is generally referred to as ocean acidification.

Ocean acidification takes place when carbon dioxide in our atmosphere is absorbed by the ocean, lowering the pH. This naturally occurring process is accelerated by our fossil fuel emissions, resulting in global oceans that are now 26 per cent more acidic than before the industrial revolution.

Parliamentarians, staffers, industry reps, and NGOs gathered in Centre Block to hear from Bill Dewey, Manager of Public Policy and Communications for Taylor Shellfish Farms. Bill came to Parliament to give us an on-the-ground report of ocean acidification’s impacts on the shellfish industry in the Pacific Northwest. As WWF’s CEO David Miller remarked, Bill helped us to “make the connection between the global and the local.”

Continue reading ‘The pH is falling! Oysters and economics on the Hill’

Behavioural responses to simulated bird attacks in marine three-spined sticklebacks after exposure to high CO2 levels

The rising partial pressure of CO2 (pCO2) in oceanic water, termed ocean acidification, is an impending threat to marine life and has previously been shown to affect several aspects of fish behaviour. We evaluated the behavioural response to a simulated avian predator attack and lateralisation in three-spined sticklebacks (Gasterosteus aculeatus) after 10 and 20 days of exposure to present-day pCO2 (400 μatm) or elevated pCO2 (1000 μatm). We show that elevated pCO2 lead to reduced behavioural lateralisation. However, no major differences in the sheltering response after an overhead avian attack were observed; fish from both treatments exhibited similar and strong responses. Compared to fish exposed to high pCO2, the control fish took longer time to freeze (i.e., stop moving) after attack at day 20 but not day 10. The freezing duration was significantly reduced between day 10 and day 20 in elevated pCO2, whereas no such reduction was observed in the control-group. However, no significant differences between treatment groups were detected at day 20. These results demonstrate that behaviour is indeed altered by high CO2 levels, although the general responses to avian predation stimuli remain similar to those of unexposed fish, indicating that some predator avoidance behaviours of three-spined sticklebacks are robust to environmental disturbance.

Continue reading ‘Behavioural responses to simulated bird attacks in marine three-spined sticklebacks after exposure to high CO2 levels’

Oyster farmers and ocean acidification (text & video)

The ocean is so acidic that it is dissolving the shells of our baby oysters,” says Diani Taylor of Taylor Shellfish Farms in Shelton, Washington. She and her cousin Brittany are fifth-generation oyster farmers, and are grappling with ocean waters that are more acidic and corrosive than their fathers, grandfathers, and great-grandfathers knew.

Continue reading ‘Oyster farmers and ocean acidification (text & video)’

Design, construction, and operation of an actively controlled deep-sea CO2 enrichment experiment using a cabled observatory system

We describe the design, testing, and performance of an actively controlled deep-sea Free Ocean CO2 Enrichment (dp-FOCE) system for the execution of seafloor experiments relating to the impacts of ocean acidification on natural ecosystems. We used the 880 m deep MARS (Monterey Accelerated Research Initiative) cable site offshore Monterey Bay, California for this work; but the Free Ocean CO2 Enrichment (FOCE) system concept is designed to be scalable and can be modified to be used in a wide variety of ocean depths and locations. The main frame is based on a flume design with active thruster control of flow and a central experimental chamber. The unit was allowed to free fall to the seafloor and connected to the cable node by remotely operated vehicle (ROV) manipulation. For operation at depth we designed a liquid CO2 containment reservoir which provided the CO2 enriched working fluid as ambient seawater was drawn through the reservoir beneath the more buoyant liquid CO2. Our design allowed for the significant lag time associated with the hydration of the dissolved CO2 molecule, resulting in an e-folding time, τ, of 97 s between fluid injection and pH sensing at the mean local T=4.31±0.14 °C and pHT of 7.625±0.011. The system maintained a pH offset of ~0.4 pH units compared to the surrounding ocean for a period of~1 month. The unit allows for the emplacement of deep-sea animals for testing. We describe the components and software used for system operation and show examples of each. The demonstrated ability for active control of experimental systems opens new possibilities for deep-sea biogeochemical perturbation experiments of several kinds and our developments in open source control systems software and hardware described here are applicable to this end.

Continue reading ‘Design, construction, and operation of an actively controlled deep-sea CO2 enrichment experiment using a cabled observatory system’

Ocean acidification (audio)

The most serious, debilitating circumstance affecting the ocean today may be acidification, the changing pH or acid balance in the water column with devastating impacts on the marine food chain, species migration and reproduction. In this episode of World Ocean Radio, host Peter Neill will report on the recently-released 20 Facts About Ocean Acidification.

Continue reading ‘Ocean acidification (audio)’

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