Lesson Title: Understanding The Harmful Effects of Ocean Acidification on Marine Life through simulation
Grade Level: 11-12
Prepared by: Molly Nation Subject Area(s): Marine Science Associated with: Chemistry Unit
Time Required: 1 class period (beginning and end of experiment)
Background For tens of millions of years, Earth's oceans have maintained a relatively stable level of acidity. It is within this steady environment that the rich and varied web of life in today's seas arose and flourished. But scientific research done by NOAA (National Oceanic and Atmospheric Administration) shows that a recent and rapid drop in the pH of the water near the surface of the ocean could undo this ancient balance, which can have devastating global consequences.
Since the beginning of the industrial revolution in the early 1800s, fossil fuel-powered machines have driven an unprecedented burst of human industry and advancement. The unfortunate consequence, however, has been the emission of billions of tons of carbon dioxide (CO2) and other heat trapping gases into Earth's atmosphere.
Scientists now know that about half of this anthropogenic, or man-made, CO2 has been absorbed by the oceans. This has benefited us by slowing the climate change these emissions would have instigated if they had remained in the atmosphere. The result of this is that the massive amounts of CO2 that the oceans have already absorbed has altered the water chemistry, which affects the life cycles of many marine organisms, particularly those at the lower end of the food chain. Carbonic Acid
When carbon dioxide dissolves in the oceans, carbonic acid (H2CO3) is formed. This leads to higher acidity (lower pH), mainly near the surface, which has been proven to inhibit shell growth in marine animals and is suspected as a cause of reproductive disorders in some fish.
On the pH scale, which runs from 0 to 14, solutions with low numbers are considered acidic and those with higher numbers are basic. Seven is neutral. Over the past 300 million years, the pH of the oceans has been slightly basic, averaging about 8.2. Today, it is around 8.1, a drop of 0.1. Because pH is a logarithmic scale, this small numeric change represents a 25% increase in acidity since the beginning of the industrial revolution in the early 1800s.
July 2016 Carbon Storehouse The oceans currently absorb about a third of human-created CO2 emissions, roughly 22 million tons per day. Projections based on these numbers show that by the end of this century, continued emissions could reduce ocean pH to 7.6, a decrease of 0.5. Shell-forming animals including corals, oysters, shrimp, lobster, many planktonic organisms, and even some fish species could be gravely affected.
Equally worrisome is the fact that as the oceans continue to absorb more CO2, their capacity as a carbon storehouse could diminish. That means more of the carbon dioxide we emit will remain in the atmosphere, further aggravating global climate change.
Scientific awareness of ocean acidification is relatively recent, and researchers are just beginning to study its effects on marine ecosystems. Fossil and other evidence indicate that for tens of millions of years the Earth's oceans have maintained a relatively stable level of acidity. It is within this steady environment that the rich and varied web of life in today's seas has arisen and flourished. However, as the oceans acidify, marine species will be under increasing pressure to adapt to their habitat's changing chemistry or become extinct. (Source: National Geographic)
Learning Objectives: 1. Students will be able to define ocean acidification. 2. Students will be able to understand and apply a simulation of the effects of ocean acidification on marine life. 3. Students will understand why is important to understand the effects of dissolved CO2 in our oceans. 4. Students will be able to link ocean acidification to its effects on marine life.
5. Students will be able to explain the relationship among the human production of CO2, ocean acidification, and climate change.
Procedure:
Teacher leads discussion about the effects of Global Climate Change and the addition of CO2 into our atmosphere and how it can relate to Ocean Acidification. To simulate the negative effects of lower pH ocean water on marine life the students will create a simulation using household acids or chemicals available to them in their classrooms.
July 2016 Lesson Title: Understanding The Harmful Effects of Ocean Acidification on Marine Life through simulation
What factors Influence Ocean Acidification? ______
Procedure: 1. Obtain 2 shells and find the mass of each shell. 2. Place 100 mL of vinegar in a beaker and a shell. Label the beaker. Make observations. (Does it fizz/bubble/nothing/move/etc.) 3. Place 100 mL of water in a beaker and a shell. Label the beaker. Make observations. (Does it fizz/bubble/nothing/move/etc.) 4. Recheck each shell. Make observations. 5. Graph your data.
Data: Solution Mass Day 1 Mass Day ______Mass Day ______Observations Observations Observations
100 mL vinegar
100 mL
H2O Conclusions and Data Analysis: 1) How is ocean acidification happening in our oceans?
2) What sorts of negative effects does ocean acidification have on marine animals? (Specifically those made of Calcium Carbonate)
3) How could climate change factors influence the future of marine life in our oceans?
4) What future impacts could these changes have on our oceans and ocean life?
5) How did your final and initial weight of your Calcium Carbonate sample change? What do you think happened to the material and why do you think this happened?
6) What can be done to help slow the process of ocean acidification? How can you personally influence this change?