Food for Thought: Connecting Ocean Acidification to Global Food Scarcity

Alissa Matus, Fullerton College, Chemistry

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Initial Publication Date: August 6, 2024

Summary

In this activity, students explore the connection between ocean acidification, food resources and related climate impacts on humans and local ecosystems. Chemistry connections include acids, bases, weak acid equilibrium, Le Chatlier principle, Henry's Law, buffers, common ion effect, and/or equilibrium. Before engaging in this activity, students should already be familiar with balancing equations, stoichiometry, the basics of acid and base neutralization reactions. Student tasks include watching a couple short videos, short readings, online and in-class discussion assignments, and civic engagement components where students practice their science literacy and communication skills.

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Learning Goals

1. Apply equilibrium chemistry (Le Chatelier's principle and other potential chemistry connections) and acid-base equilibria to ocean acidification.

2. Describe the downstream effects of the chemistry of ocean acidification on humans worldwide.

3. Practice clearly communicating chemistry and science topics with a non-science audience.

4. Describe how scientists are addressing the problems faced by coral reefs due to ocean acidification.

Context for Use

This is a short and informal activity appropriate for an introductory preparatory chemistry class to help students connect the chemistry they are learning in class with real-world issues of climate change and social justice. The activity aims to build students' confidence in their STEM-identity and empower them to become comfortable with science communication. This activity was designed to take place during parts of lab and classroom sessions in a small (26 person) in-person class that prepares students to take the General Chemistry series for STEM majors. Most students who take this class have either never taken a chemistry class or have not taken a college-level chemistry class. This activity took place towards the end of the quarter or semester, and prior to students conducting a weak-acid titration lab. This activity is appropriate for high school through college level general chemistry. The chemistry topics this activity connects well with include acids, bases, weak acid equilibrium, Le Chatlier principle, Henry's Law, buffers, common ion effect, and/or equilibrium. Before engaging in this activity, students should already be familiar with balancing equations, stoichiometry, the basics of acid and base neutralization reactions.

Description and Teaching Materials

About one hour of class time is needed to implement this activity with a class of about 26 students.

Instructor Class Preparation: I check documentary links, create an online discussion post for students to reflect on their science communication, civic engagement assignment.

Step 1: (20 minutes) Online and In-Person.

Pre-class work: I assign this video before students begin this activity, which provides a broad overview of ocean acidification and its implications for the future: https://www.youtube.com/watch?v=OVWZyDz--30.

In Class: Students watch two short (1-2 minute) videos in class:

  1. A short clip (only from 8:35 to 10:36) from the same video in class to show how human livelihoods can be directly impacted by ocean acidification(https://www.youtube.com/watch?v=OVWZyDz--30).
  2. A 2- minute video of Hannah Barkley discussing coral reef research (vimeo.com/181102864).

Following watching the videos, I lead the class through balancing the chemical equation for the dissolution of carbon dioxide into seawater water to form carbonic acid, as follows:

  1. CO2 + H2O -> H2CO3
  2. H2CO3 -> H ++ HCO3-

I then ask the students to check that the equation is balanced (atoms and charges) and emphasize that the above equations represent ocean acidification. I also share data and information on how an estimated 20% of the global population's primary nutrition source is ocean life. Finally, students brainstorm to come up with as many communities as they can think of who rely on ocean life for their nutrition. Students then come up to the board to write down their ideas. Here, I expect my students to draw from what they've learned from the videos we've watched together, and their own general knowledge.

Step 2:  (approximately 10 to 15 minutes, asynchronous) Online: Students read one of the following articles and respond to the following prompts in an online discussion.

Articles to choose from:

  1. Reversing Ocean Acidification: https://www.calacademy.org/explore-science/reversing-ocean-acidification
  2. Re-Carbonizing the Sea: https://news.mongabay.com/2023/01/re-carbonizing-the-sea-scientists-to-start-testing-a-big-ocean-carbon-idea/#:~:text=Oceans%2C%20Planetary%20Boundaries-,Re%2Dcarbonizing%20the%20sea%3A%20Scientists%20to%20start%20testing,a%20big%20ocean%20carbon%20idea&text=Ocean%20alkalinity%20enhancement%20(OAE)%20involves,%2C%20albeit%20temporarily%2C%20ocean%20acidification.
  3. Great Barrier Reef Alkalinity: https://iopscience.iop.org/article/10.1088/1748-9326/ac002d 

Discussion Prompts:

  1. Describe ocean acidification in your own words.
  2. Summarize the article you selected to read and relate it to the chemical reaction of ocean acidification we discussed in class (100 words or less).
  3. What feelings or emotions does the article you read evoke in you? How does this new information relate to our in-class discussions on ocean acidification?  

Step 3:  (30 minutes) In Person.

In class, students learn what science communication is, what its aims are, where/how people can access it, and what role politics sometimes plays in science communication.  I help students consider what they can learn and interpret with their new chemistry knowledge from the class and how they can use that knowledge.  I also ask them to identify friends or family members with whom they can share this information.  We explore ways to convey this information to people in their lives in ways that don't distress or burden the person they are sharing with. I suggest that students choose a person they feel comfortable speaking with, and who, ideally, has not taken a chemistry class.

Another civic or community engagement option is for students to contact a legislator and/or invite a legislator to visit class in person or online. Students could call, submit a letter, or make public comments on local legislation related to ocean acidification and/or fisheries, such as commenting on California's ocean acidification action plan (https://www.opc.ca.gov/oa-action-plan/).

An example template to support student letter writing is linked here: https://docs.google.com/presentation/d/1JO0v0nNv79lVZNkOZc6zbZNxVRqVuw6tqLL5fH5M5ig/edit#slide=id.p1 .

In person, I usually return to the video students watched at the outset, and share how it is a good example of a positive story of change. Hannah Barkley Video: vimeo.com/181102864  This video gives the audience a sense of community, hope for protecting and repairing coral reefs harmed by climate change, and is informational regarding scientific research related to coral reefs and climate change. This video is also a good example of science communication that communicates the science clearly and ends on a positive, hopeful note.

I also summarize and make optional the following Katharine Hayhoe TED talk on the importance of talking about climate change and how to have a positive discussion with the people in your life:  https://www.ted.com/talks/katharine_hayhoe_the_most_important_thing_you_can_do_to_fight_climate_change_talk_about_it?trigger=5s

Teaching Notes and Tips

For class discussions, I introduce students to "think-pair-share discussions" both in class and online prior to this activity. If this is your first activity that includes discussion in class and/or online, I recommend taking time to brainstorm with students what makes a positive and safe discussion space. Students usually come up with these guidelines and more Discussion Guidelines (serc pub).docx (Microsoft Word 2007 (.docx) 16kB Jul17 24). For example, the guidelines used in my classroom are adapted from the Inclusive STEM Teaching Project:

  • Strive for intellectual humility. Write and engage in a humble, meaningful way. Be open to new ideas that might challenge your lived experiences.
  • Assume that your classmates are speaking, writing, or sharing with the best intentions. We must give the benefit of the doubt to each other when we communicate online, especially because our communications take time to write and think about. From the Inclusive STEM Teaching Project: "we offer this guideline to encourage us to think about the impact of our words before we speak them so that we can aspire to assume that people are speaking, writing, or sharing with the best intentions."
  • Respect confidentiality. What is said stays here. What you learn here leaves here. Give other students the same amount of privacy that you expect for yourself and the information you share here.
  • Recognize how your own social positionality (e.g., race, class, gender, sexuality, ability) informs your perspectives and reactions to others. No two people have the same lived experiences. We must always respect the identities of others, no matter what. We are also owed that respect from everyone we interact with.
  • Differentiate between your opinions and informed knowledge. Informed knowledge comes from lived experience, study, and practice. Be willing to engage with new research or ideas.

Assessment

1. Apply equilibrium chemistry (Le Chatelier's principle and other potential chemistry connections) and acid-base equilibria to ocean acidification.

I do an informal, formative assessment of the class, observing the process they follow in balancing the ocean acidification chemical equation.

2. Describe the downstream effects of the chemistry of ocean acidification on humans worldwide.

Following students' watching the videos, I formatively assess their understanding of the material through their think-pair-share, brainstorm part of Step 1 of the activity, for students' understanding of the ways people and communities experience injustice related to ocean acidification and how they can address the challenges they face.

3. Practice clearly communicating chemistry and science topics with a non-science audience.

To assess this, I observe student learning and understanding as they take part in online discussions and/or in class conversations using a summative assessment, and for the summative assessment I grade the students' letter or comment to policy makers. For a satisfactory grade, students should mention the impact of ocean acidification on human life and how that may impact our local communities.

4. Describe how scientists are addressing the problems faced by coral reefs due to ocean acidification.

To assess this, I observe student learning and understanding as they take part in watching the videos and taking part in the online discussions and/or in class conversations using an informal formative assessment. I expect students to be able to summarize their conversations and present their ideas clearly. I look for the changes they make in their comments or discussion posts, and expect them to develop more as we continue to discuss ocean acidification.

References and Resources

This work is supported in part by NSF-IUSE grant (DUE 2043535).

List of suggested readings and videos to assign or show in class:

  1. Reversing Ocean Acidification (Article) https://www.calacademy.org/explore-science/reversing-ocean-acidification
    1. Scientist Rebecca Albright describes her research efforts in modifying coral reef pH to combat ocean acidification.
  2. Re-carbonizing the sea: Scientists start testing a big ocean carbon idea (Article) https://news.mongabay.com/2023/01/re-carbonizing-the-sea-scientists-to-start-testing-a-big-ocean-carbon-idea/#:~:text=Oceans%2C%20Planetary%20Boundaries-,Re%2Dcarbonizing%20the%20sea%3A%20Scientists%20to%20start%20testing,a%20big%20ocean%20carbon%20idea&text=Ocean%20alkalinity%20enhancement%20(OAE)%20involves,%2C%20albeit%20temporarily%2C%20ocean%20acidification
    1. The benefits of ocean alkalinity enhancement are introduced by California scientists.
  3. Reversing Ocean Acidification (Article)https://iopscience.iop.org/article/10.1088/1748-9326/ac002d
    1. The alkalinity of the Great Barrier Reef is discussed and future projections are made.
  4. California Ocean Acidification Action Plan (Resource) https://www.opc.ca.gov/oa-action-plan/
    1. California's ocean acidification action plan.
  5. Scientific Writing Skills for Climate Action (Template) https://docs.google.com/presentation/d/1JO0v0nNv79lVZNkOZc6zbZNxVRqVuw6tqLL5fH5M5ig/edit?usp=sharing
    1. An example template to support student letter writing.
  6. Ocean Acidification (Resource) https://www.coastal.ca.gov/publiced/oa.html
    1. California state government's description of ocean acidification.