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Thermal Influence on Algal Resistance to Acid Precipitation

This study investigates the impact of elevated temperature on the survivorship and resistance of algae to decreased pH caused by acid precipitation and acid mine drainage. The results reveal the complex interactions between temperature, acidity, and algal health.

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Thermal Influence on Algal Resistance to Acid Precipitation

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  1. Thermal Influence on Algal Resistance to Acid Precipitation Connor P. Jackson PJAS Central Catholic High School

  2. Thermal Pollution • Often created by industrial processes • Warm water entering normally cold aquatic environment/storm runoff • Lack of shore vegetation • Decrease metabolism of algae • Reduces dissolved oxygen level

  3. Acid Precipitation • Worldwide problem • Caused by pollution of sulfur dioxide and nitrogen oxide • Often originates from smokestacks, vehicle exhaust, and burning fossil fuels • Average pH of 5.6

  4. Acid Mine Drainage • Outflow of acidic water from abandoned metal mines or coal mines • Caused by water flooding the mine and oxidizing metal sulfides • Thus H+ is released and the pH is lowered • The greatest contributor to AMD is pyrite oxidation • The equation is: 2FeS2(s) + 7O2(g) + 2H2O(l) → 2Fe2+(aq) + 4SO42-(aq) + 4H+(aq)

  5. Environmental Problems in Pennsylvania • Acid Precipitation • Average pH of precipitation in PA: 4.5 • Major problem due to industry • Thermal Pollution • Industry introducing hot water into normally cold aquatic environment • Acid Mine Drainage • The many abandoned coal mines in PA create a large problem for the water bodies in the area

  6. Coal Mining Areas in Pennsylvania

  7. Euglena • Protist • Euglenophyte because of chloroplasts • 20-300 μm in length • If photosynthesis is not possible, can absorb nutrients from decaying material • Flagellum propels cell through the water by pulling with a whip-like motion • Has an Eyespot to orient itself towards light • Can also make an inchworm-like movement • Found in nutrient-rich freshwater

  8. Chlamydomonas • Genus of green algae • Has an Eyespot to orient itself to light • Two flagella, and swims with a breaststroke-like motion • 10 μm in diameter • Large,crescent-shaped chloroplasts • Found in freshwater, soil, oceans, and snow

  9. Purposes • Does elevated temperature decrease the survivorship of algae? • Does decreased pH caused by acid precipitation and acid mine drainage decrease the survivorship of algae? • Does elevated temperature influence algae’s resistance to decreased pH? 12

  10. Null Hypotheses • Elevated temperature does not decrease the survivorship of Chlamydomonas reinhardtii and Euglena sp. • Decreased pH caused by acid precipitation and acid mine drainage does not decrease the survivorship of Chlamydomonas reinhardtii and Euglena sp. • Elevated temperature does not influence the resistance of Chlamydomonas reinhardtii and Euglena sp. To decreased pH.

  11. Materials • Chlamydomonas reinhardtii • Euglena sp. • Spectrophotometer • Spring Water • 0.5M Sulfuric Acid • 3 grow lights • 2 Space heaters • 48 Test tubes • 3 test tube racks • Macro and micro pipettes and tips • Sharpie

  12. Procedures • Fill tubes as follows for 3 temperature experimental groups (20°C, 25°C, 33°C)

  13. Procedures • Absorbance readings recorded at 430 nm for all tubes • 20°C tube rack placed in front of grow light. • 25°C tube rack placed in front of grow light and space heater set to maintain water temperature of 25°C. • 30°C tube rack placed in front of grow light and space heater on highest setting to attain highest water temperature possible (attained 33°C). • Absorbance readings recorded on days 1, 3, 5, 8, 11, 13, and 15. • Spring water was added to the tubes as needed to replace water lost due to evaporation. 16

  14. Absorbance 430 nm Day Day

  15. Absorbance 430 nm Day Average Absorbance

  16. Acid/Temperature Interaction (Euglena) p value=0.0037 (Reject Null Hypothesis Mean % Change Absorbance Tube Set • At 20°C,acid slightly decreases % change over no-acidd little to no effect • At higher temperatures, the acid had little to no effect

  17. Acid/Temperature Interaction (Chlamydomonas) p value=0.018761746 (Reject Null Hypothesis Mean % Change Absorbance Tube Set • At 20°C, acid creates a slightly lower % change than no-acid • At 25°C, the difference in % change is more pronounced • At 33°C, there is vary little, if any interaction between the two

  18. ConclusionsResults • The hypothesis that elevated temperature does not decrease the survivorship of algae was REJECTED. • The hypothesis that decreased pH caused by acid precipitation and acid mine runoff does not decrease the survivorship of algae was REJECTED. • The hypothesis that elevated temperature does not influence algae’s resistance to decreased pH was REJECTED. • These null hypotheses were rejected due to the p value being <.05.

  19. ConclusionsFurther Findings • Euglena has a very low tolerance to higher temperatures. • Chlamydomonas has a very low tolerance to acid. • Acid and thermal interaction changes with different temperatures and different models. The effectiveness of the acid depends on the temperature. 22

  20. ConclusionsLimitations • The cultures of algae are not sterile (non-monocultural), thus it is possible for other species to be present. • Algae health may have fluctuated independently of the variables. • Due to nature of the experiment, it was difficult to maintain the exact correct temperature and water level in the tubes over time.

  21. ConclusionsExtensions • Test with natural aquatic waters • Test with different types of algae, or other organisms • Test with different temperatures, some higher, some lower • Test with different concentrations of acid • Test with different chemicals • Longer time for testing • Test with monoculture

  22. ConclusionsAcknowledgements/References • Dr. John Wilson Biostatistician University of Pittsburgh • http://en.wikipedia.org/wiki/Thermal_pollution • http://www.chlamy.org/info.html • http://www.yale.edu/rosenbaum/green_yeast.html • http://en.wikipedia.org/wiki/Chlamydomonas_reinhardtii • http://en.wikipedia.org/wiki/Chlamydomonas • http://www.physics.ohio-state.edu/~kagan/phy367/P367_articles/AcidRain/effects-on-lakes.html • http://www.polmar.com/pollution/thermique_e.htm • http://en.wikipedia.org/wiki/Euglena • http://staff.jccc.net/pdecell/protista/euglena.html • http://www.jracademy.com/~mlechner/archive1999/euglena.html • http://www.maine.gov/dep/blwq/doceducation/nps/thermal.htm • http://www.anr.state.vt.us/site/html/reflect/April5.htm • http://encarta.msn.com/text_1741500922___0/Thermal_Pollution.html • http://www.rpi.edu/dept/chem-eng/Biotech-Environ/Environmental/THERMAL/tte1.htm

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