OCEAN ACIDIFICATION

Presented by Nabiilah Naraino MajieDate: 26th February 2016

Table of Content• Introduction• CO2 and ocean chemistry• Impact of ocean acidification• Mitigation• Conclusion• References

INTRODUCTION

Introduction• Ocean acidification: ongoing decrease in the pH of the

Earth's oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere.

• Oceans play a critical role in the global carbon cycle by absorbing about a quarter of the CO2 emitted to the atmosphere from human activities.

• CO2 emissions acidity of the world’s oceans– Affects marine plants and animals especially those that require

calcium carbonate to grow and survive, and other species that rely on these for food.

CO2 and ocean chemistry

CO2 and ocean chemistry• Ocean absorbed 1⁄4 of CO2 from the atmosphere.

• This CO2 would otherwise have accumulated in the atmosphere leading to greater climate change.

• However, the absorption of this CO2 has affected ocean chemistry– oceans (slightly alkaline) more acidic.

• The average pH of oceanic surface waters has been lowered by 0.1 units since the pre-industrial period.

• This represents a 30% increase in hydrogen ion activity

Impact of ocean acidification

BIOLOGICAL PROCESSES AFFECTED BY OCEAN ACIDIFICATION

• Increasing acidity, combined with other environmental stressors like increasing ocean temperature and pollution, has the potential to affect many biological processes.– Building shells– Maintaining metabolism– Boosting photosynthesis– Obtaining essential minerals & nutrients

Building Shells

• Many animals and some algae use carbonate ions to make calcium carbonate shells and skeletons.

• Ocean acidification: CO32-

– Organisms work harder to produce shells.

Maintaining metabolism• Many physiological processes operate

within a narrow pH range; outside of that range,– biochemical reactions may be too slow or – in efficient to keep the organism healthy.

• Species can adjust to changes in their surroundings by – actively maintaining a constant internal

environment, – this maintenance requires a significant

expenditure of energy.

Boosting photosynthesis• Carbon dioxide can stimulate plant

growth by boosting the rate of photosynthesis.

• growth of seagrasses under elevated carbon dioxide conditions.

• Seagrasses provide valuable habitat, but if these plants overgrow– reduce the ecosystem’s biodiversity

Obtaining Essential Minerals and Nutrients• Ocean acidification could make

it harder for marine organisms to absorb nitrogen, phosphorus, iron, and other elements essential for growth.

• For example, when seawater becomes more acidic, iron attaches to organic compounds, preventing marine life from using this essential element.

EFFECTS ON SHELLFISH, CORALS, AND OTHER CALCIFIERS

• Calcifiers—organisms with shells or skeletons made from calcium carbonate—are among the most abundant forms of marine life.

• Ocean acidification decreases the availability of carbonate ions– Dissolving pteropod shells– Neurological effects

DISSOLVING PTEROPOD SHELLS• Tiny sea snail- called the pteropod. • Despite their small size, pteropods

are an important source of food for many species, including fish, seals, and whales.

• But pteropods have delicate calcium carbonate shells that are vulnerable to ocean acidification.

NEUROLOGICAL EFFECTS• Ocean acidification can affect fishes’ sense of smell and

alter their behaviour. • In more acidic conditions, young clownfish loses the ability

to navigate home using their sense of smell. • Fish are attracted to odours they normally avoid, such as the

scent of predators, and displayed uncharacteristically bold behaviours such as roaming far from their home reef.

POTENTIAL EFFECTS ON ECOSYSTEMS AROUND THE GLOBE

• The Effects of ocean acidification will vary – from place to place, depending on the habitat and – the types of organisms in the ecosystem.

The Open Ocean Tropical Coral Reefs Polar Ecosystems Deep Water Coral Reefs

THE OPEN OCEAN• Tiny free-floating plants and animals

– live and grow in sunlit surface waters and – serve as the foundation of the marine food chain.

• Planktonic species need carbonate ions to build their shells.

• If ocean acidification increases, these carbonate-based plankton species may decline.

• Range of species, including fish, seals, and whales, could lose their preferred foods, or have less food altogether.

TROPICAL CORAL REEFS• Corals must grow rapidly to outpace predation by fish and

other organisms, and to compete for space with algae and sea grasses.

• Ocean acidification prevents reef building corals from growing fast enough to escape predation and competition, or to repair physical damage sufficiently.

• Slowed growth is not the only impact that ocean acidification could have on coral reefs– coral bleaching.

POLAR ECOSYSTEMS• The polar waters of the Arctic and Southern oceans

– harbor many protected and endangered marine mammals and – support some of the most productive fisheries in the world.

• Carbon dioxide dissolves more readily in cold water, acidifying polar waters faster than in lower latitudes.

• Ocean will begin to become corrosive to some types of carbonate structures by the year 2050 if carbon dioxide emissions continue to increase at the current rate.

DEEP WATER CORAL REEFS• Corals are also found in the deep sea, up to 1000 meters

below the surface of the ocean, where they create habitat for many species of fish.

• Ocean acidification will take longer to reach the deeper waters, – but for tropical reefs, over time it could reduce calcification,

decreasing the rate of growth of deep-water corals.• Deep-water species may be

– less able to tolerate changing conditions than their shallow water counterparts.

– less able to cope with an increasing ocean acidity.

Mitigation

MitigationCombating Acidification requires:• Reducing carbon dioxide emission and

improving the health of the ocean.• Creating marine protected areas and

stopping destructive fishing practices.• Addition of Alkali to the Oceans.• Adding of lime stone carbonate

material.• Plantation of trees.• Green belt around the industries.

Conclusion

Conclusion• Due to ocean acidification , the

ocean’s capacity as carbon store house is diminishing.

• If nothing is done to help curb ocean acidification , its negative impact may be felt on the marine environment , local communities , and all the way up through the global economy.

REFERENCES• Elen Barla, 2012, Ocean Acidification, Slideshare. Available at: http://www.slideshare.net/ElenBarla/ocean-acidification-14866953 Accessed on 25th Feb

2016• Bankoku Shinryokan, 2011, IPCC Workshop on Impacts of Ocean Acidification on Marine Biology and Ecosystems, Intergovernmental Panel on Climate

Change. Available online at: https://www.ipcc-wg2.gov/meetings/workshops/OceanAcidification_WorkshopReport.pdf Accessed on 25th Feb 2016• Sebastian Hennige, J. Murray Roberts and Phillip Williamson, 2014, An Updated Synthesis Of The Impacts of Ocean Acidification On Marine Biodiversity,

CBD Technical Series No. 75. Available online at: https://www.cbd.int/doc/publications/cbd-ts-75-en.pdf Accessed on 25th Feb 2016• Prof John Raven FR, Dr Ken Caldeira, Prof Harry Elderfield FR, Prof Ove Hoegh-Guldberg, 2005, Ocean acidification due to increasing atmospheric

carbon dioxide, The Royal Society-Report. Available at: http://www.us-ocb.org/publications/Royal_Soc_OA.pdf Accessed on 25th Feb 2016• Great Barrier Reef, 2016, Impacts of ocean acidification on the Reef. Managing the reefs. Available online at:

http://www.gbrmpa.gov.au/managing-the-reef/threats-to-the-reef/climate-change/how-climate-change-can-affect-the-reef/ocean-acidification Accessed on 25th Feb 2016

• The National Oceanic and Atmospheric, 2010, Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean, NASA, the National Science Foundation, and the U.S. Geological Survey. Available online at: http://dels.nas.edu/resources/static-assets/materials-based-on-reports/booklets/OA1.pdf Accessed on 25th Feb 2016

• Orr, J.C., K. Caldeira, V. Fabry, J.P. Gattuso, P. Haugan, P. Lehodey, S. Pantoja, H.O. Pörtner, U. Riebesell, and T. Trull, M. Hood, E. Urban, and W. Broadgate. 2009. Research Priorities for Ocean Acidification, report from the Second Symposium on the Ocean in a High-CO2 World, Monaco, October 6-8, 2008, convened by SCOR, UNESCO-IOC, IAEA, and IGBP, 25 pp. Available online at: http://www.nap.edu/read/12904/chapter/13#185 Accessed on 25th Feb 2016

• Kelvin Boot, Jacqueline Alder, Marcella Carew, 2010, Environmental Consequences Of Ocean Acidification: A Threat To Food Security, UNEP Emerging Issues. Available online at: http://www.unep.org/dewa/Portals/67/pdf/Ocean_Acidification.pdf Accessed on 25th Feb 2016

• Chen Zu, Howard Alper, 2009, Iap Statement On Ocean Acidification, Interacademy Panel On International Issues. Available online at: http://www.interacademies.net/10878/13951.aspx Accessed on 25th Feb 2016

Thank You