Lab 2 Ocean Acidification and Global Warming lab Samantha Oliveira 10 12 2022 Materials and Methods The purpose of this lab was to observe and test the ocean s acidity levels and if it had any effect on coral reefs Five identical tubes were placed in the ocean containing two different types of corals Acropora Intermedia Nobilis and Porites lobata Over a period of six months these corals were observed Tube 1 was the control tube and no changes were made to it throughout the six month period Each tube was equipped with an Underwater Pulse Amplitudes Modulated Fluorometer Fv Fm that took measurements during the experiment There was also an Underwater Digital Microscope placed inside each tube to observe and record the symbiosis occurring A pH meter was also used to measure ocean acidification changes as the variables were altered along with a transect to measure coral bleaching percentages Tube 1 control started at 400 ppm and 25 degrees Celsius Tube 2 s temperature was increased by three degrees and Tube 3 s ppm was increased to 750 Tube 4 s temperature was also increased by three degrees but the CO2 exposure was changed to 750 Lastly Tube 5 s temperature remained at 25 degrees but the ppm was changed to 1500 Table 1 measurements taken during observations including temp CO2 concentrations Fv Fm measurements pH levels bleaching and calcite dissolution for both Acropora and Porite Tubes Time pCO2 temp pH Acropora porites Acropora Porites Acropora Porites months ppm Fv Fm Fv Fm bleach bleach Cal Dis Cal Dis control 400 25 8 05 green green 0 N A N A 0 6 6 6 6 6 Control Tube 2 Tube 3 Tube 4 Tube 5 400 400 25 28 8 05 green green 0 8 05 yellow yellow 15 750 25 7 82 yellow yellow 7 750 28 7 82 red red 29 1500 25 7 55 red red 30 0 0 8 3 22 20 No Change No Change No Change No Change Small Change Small Change Small Change Small Change Large Change Large Change Table 2 Measurements taken during observations including the changes in temperature CO2 concentration pH level Fv Fm measurements bleaching percentage and calcite dissolution for both Acropora and Porites Tubes Time temp pH Acropor a porites Acropor a Porites Acropor a Porites pCO 2 months ppm Fv F m Fv F m bleach bleach Cal Dis Cal Dis control 400 25 8 05 green green 0 N A N A Control 400 25 8 05 green green 750 25 7 82 yellow yellow 0 0 3 0 7 1500 25 7 55 red red 30 20 400 28 8 05 yellow yellow 15 8 750 28 7 82 red red 29 22 No Change No Change Small Change Small Change Large Change Large Change No Change No Change Small Change Small Change 0 6 6 6 6 6 Tube 3 Tube 5 Tube 2 Tube 4 Figure 1 A measure of how pH balance changes as CO2 concentration increases Figure 2 bleaching of Acropora and Porites Figure 3 bleaching of Acropora and Porites as a function of pH levels at two different temperatures Blue Acropora at 25 C Gray Acropora at 25C Orange Porites at 25C Yellow Porites at 28C Discussion and Conclusions Coral reefs are the building blocks for the entire marine ecosystem they provide shelter and food for fish and many other marine life Often referred to as the rainforest of the sea due to its importance and diversity the amount of coral in the ocean is rapidly declining due to ocean acidification Our ocean is one of if not the largest carbon pools on the planet and is becoming more and more acidic as time goes by Because of human driven increased levels of carbon dioxide in the atmosphere there is more CO2 dissolving into the ocean The ocean s average pH is now around 8 1which is basic or alkaline but as the ocean continues to absorb more CO2 the pH decreases and the ocean becomes more acidic NATO The increasing pCO2 decreases the pH The water becomes more basic due to the acid dissociation into carbonate ions and hydrogen ions that eventually form H3O ions an increase in CO2 will cause a decrease in pH because the solution is getting more acidic When pCO2 increases regardless of the temperature it increases the bleaching Looking at the data we can see that pCO2 affects the Acropora a little bit more than it does the Porites For example when the pCO2 was at 750 the acroporas bleaching was at 29 and the Porites was at 22 We can see that when the pH is lower the bleaching in both the acropora and porites is higher The porites seem to be affected less than the acropora when the pH is lower The Porites bleaching was 20 with a pH of 7 55 and the Acroporas bleaching was at 30 at the same pH When the pCO2 increases the calcite dissolution changes It does not affect the Acropora and Porites differently According to the table the results were exactly the same for both species The data shows that the lower the pH the more the calcite dissolution changed Like the previous question about the pCO2 affecting both species the acropora and porites were affected the same way due to the pH being lower When the temperatures are higher 28C it seems that the bleaching is also higher compared to when it s 25C The only time we see a higher bleaching at 25C is when the pCO2 is at 1500 which makes sense due to how high it is compared to 400 and 750 pCO2 The effects of increasing pCO2 and increasing temperature seem to have a synergistic effect on the bleaching because we see that when both the temperature and pCO2 levels increase the bleaching is higher than when just one or the other increases Both of the species are significantly affected by these factors We see that even though the temperature change was only 3 degrees any temperature rise impacts the health of both the Acropora and Porties It can be concluded that environments that are warmer and have more CO2 have a negative effect on the coral ecosystem This leads to us having more acidic ocean coral bleaching and the potential extinction of coral If we do not take action to reduce the amount of CO2 in the ocean we risk losing a vital part of the marine ecosystem We also have to think about how this affects us directly as humans Many people rely on fishing as their main source of income and if the coral reefs all die then many fish and other marine life will cease to exist The protection of coral reefs not only benefits our marine life but ours as well