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The effect of ocean acidification on the shell sizes of Ammonia beccarii

The effect of ocean acidification on the shell sizes of Ammonia beccarii. Valentin Lazar Spring Valley High School. Research Problem. Carbon dioxide in the atmosphere is increasing rapidly. About half of the carbon dioxide gets absorbed by the oceans (Doney, 2006).

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The effect of ocean acidification on the shell sizes of Ammonia beccarii

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  1. The effect of ocean acidification on the shell sizes of Ammonia beccarii Valentin Lazar Spring Valley High School

  2. Research Problem • Carbon dioxide in the atmosphere is increasing rapidly. • About half of the carbon dioxide gets absorbed by the oceans (Doney, 2006). • The oceans are absorbing too much carbon dioxide, and it is changing the pH of the oceans.

  3. Diagram by Orr, J et al., 2005

  4. Ocean acidification • Ocean acidification is defined as the process in which the pH of the oceans decrease. • This results from carbon dioxide entering the oceans. • The carbon dioxide is changing the chemistry of the oceans.

  5. Atmospheric Carbon Dioxide CO2 Carbonic Acid Hydrogen Ions CO2 + H2O H2CO3 H+ Carbon Dioxide + Water HCO3-1 CO3-2 Bicarbonate Ions Carbonate Ions

  6. Problems of ocean acidification • Some organisms use calcium carbonate (CaCO3) for shells and exoskeletons (Doney, 2006). • Calcium carbonate can dissolve in low pH environments. • Many of the organisms are important food sources (ex. plankton, foraminifers, corals)

  7. Oceans • The pH of the oceans is normally in the range of 8.3 and 7.9 (Doney, 2006). • The pH of the oceans varies with location and depth. • This study will focus on both extremes of the pH range, 8.3 and 7.9.

  8. Picture from http://www.royalsoc.ac.uk/displaypagedoc.asp?id=13539

  9. Ammonia beccarii • Ammonia beccarii are foraminifers that live in estuarine environments and stay near the bottom of shallow waters near the coast. • Ammonia beccarii eat algae and they reproduce asexually about every 30 days. • They have shells made of calcium carbonate about 300 μm in diameter.

  10. Photograph taken by Valentin Lazar

  11. Chambers Photograph taken by Valentin Lazar

  12. Why Ammonia beccarii? • They consist of calcium carbonate • They were readily available. • They are easy to manage and measure. • It is better to test live organisms because it is a real-world scenario.

  13. Previous Research • Coral was placed at pH of 8 and 7.2, and calcification was reduced (Marubini & Atkinson, 1999). • Coral was grown in ocean water with increased CO2 pressure, and calcification was reduced (Leclercq, Gattuso & Jaubert, 2002). • E. huxleyi was grown in seawater with different CO2 concentrations and deformations were visible. (Riebesell et al., 2000).

  14. Pictures taken by Riebesell et al., 2000

  15. Purpose • To identify whether ocean acidification has a significant effect on marine organisms at the oceans’ current pH range. (8.3-7.9) • To provide insight as to how serious ocean acidification is to marine organisms that use calcium carbonate.

  16. Hypothesis • As the pH of the water decreases, the shell sizes of the Ammonia beccarii will also decrease.

  17. Materials • Ammonia beccarii • Instant Ocean • LabPro pH probe • LoggerPro • Motic Images 1.2 • Algae • Hydrometer • Reef Buffer • Motic Microscope • Petri dishes • Mud • Pipettes • Air Pumps • Minitab 14 • Straws • 7 and 9 pH buffers

  18. IV: The pH of the seawater 8.3 (control) 7.9 23 23 Experimental Design Diagram DV: The diameters of the A. beccariishells (μm) C: Magnification when measuring, salinity, calibration method of pH probe, food given to each group amount of seawater in each dish/container.

  19. Methods Make seawater Measure shell sizes Mix with mud Two-sample t-test Adjust pH and salinity 15-day pH treatment Grow Ammonia beccarii Measure shell sizes Separate into two groups Two-sample t-test

  20. Pictures taken by Valentin Lazar

  21. Variable 8.3-pH (um) 7.9-pH (um) Mean 242.72 243.56 StDev 44.73 44.88 Variance 2001.16 2014.44 Minimum 158.40 172.10 Maximum 308.90 323.60 Range 150.50 151.50 Initial Descriptive Statistics

  22. Variable 8.3-pH (um) 7.9-pH (um) Mean 273.87 236.50 StDev 36.68 40.35 Variance 1345.68 1628.05 Minimum 201.30 179.70 Maximum 327.40 327.40 Range 126.10 147.70 Experimental Descriptive Statistics

  23. Initial two-sample t-test Experimental two-sample t-test

  24. Discussion • The hypothesis was accepted. • There is a significant difference between the 8.3-pH dish and the 7.9-pH dish. • Ammonia beccarii are at risk from ocean acidification today, at 7.9-pH. • The mean 7.9-pH shell size in the experiment was less than the initial mean.

  25. Variable 8.3-pH (um) 7.9-pH (um) Mean 242.72 243.56 StDev 44.73 44.88 Variance 2001.16 2014.44 Minimum 158.40 172.10 Maximum 308.90 323.60 Range 150.50 151.50 Initial Descriptive Statistics

  26. Variable 8.3-pH (um) 7.9-pH (um) Mean 273.87 236.50 StDev 36.68 40.35 Variance 1345.68 1628.05 Minimum 201.30 179.70 Maximum 327.40 327.40 Range 126.10 147.70 Experimental Descriptive Statistics

  27. Sources of Uncertainty • Conditions may not have simulated Ammonia beccarii habitat. • Did not specifically control pressure, temperature, and luminosity. • The pH or salinity may have been altered in the small petri dishes after a certain period of time.

  28. Future Research • There need to be more studies on the effects of ocean acidification on other marine organism that are of more importance to ocean ecosystems. • Long-term studies on ocean acidification in ocean ecosystems. • A way of dealing with ocean acidification before it gets any worse is also important.

  29. Acknowledgements • Dr. Chris Hintz from USC for providing me with Ammonia beccarii and giving suggestions for better improving the methodology. • My teachers from Spring Valley High School. • My parents for their encouragement and guidance.

  30. Literature Cited • Doney, S. C. (2006, March). The dangers of ocean acidification. Scientific American, 294(3), 58-65. • Leclercq, N., Gattuso, J.P., & Jaubert, J. (2002). Primary production, respiration, and calcification of a coral reef mesocosm under increased CO2 partial pressure [Electronic version]. Limnology and Oceanography, 47, 558-564. • Marubini, F., & Atkinson, M.J. (1999). Effects of lowered pH and elevated nitrate on coral calcification. Marine Ecology Progress Series, 188, 117-121. • Riebesell, U. et al. (2000, September 21). Reduced calcification of marine plankton in response to increased atmospheric CO2 [Electronic version]. Nature, 407, 364-367.

  31. The effect of ocean acidification on the shell sizes of Ammonia beccarii Valentin Lazar Spring Valley High School

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