Lesson 5c – Using Ocean Acidification Models to Make Predictions

Description: The purpose of Lesson 5c is for students to model systems approaches as they learn about today’s scientific process. Specifically, students will use mathematical and computer-based modeling to make predictions. The following Lesson 5C is being Field Tested. If you are interested in field testing these materials, please contact SEE (email see@isbscience.org) for information and to provide feedback on the new version.


Course:  Life Science, Integrated Science, STEM, BioChem, Marine Science
Unit:  Ocean Acidification, Ecology, Biogeochemical Cycling

See the NGSS buttons on the upper left and the Standards Addressed page for all NGSS, WA State (Science, Math and Literacy), and NOAA Ocean Literacy Education Standards connections. For this lesson, due to the variety of experiments students conduct preceding the lesson, students will approach these models with various levels of preparation and understanding. In addition, for this lesson, here is a breakdown of:

What Students Learn
  • The ocean is an intricate network of abiotic (nonliving) and biotic (living) factors. Systems research helps us understand and predict changes and/or reverberating effects that are likely to move through this network.
  • Research and collaboration are used by scientists as part of the scientific process. As scientists engineer and develop experiments, research helps them understand what they observe and helps them develop solutions to a problem.
  • Systems models can be used to evaluate complex situations such as ocean acidification and/or changes in biogeochemical cycling.
  • Ecosystems are dynamic, responsive, and often marked by many processes being in equilibrium.  Scientific research helps us predict how ecosystems will respond to changes within its subsystems.
What Students Do
  • Students connect their experimental work from Lesson 5A to other scientific research through using systems models and scientific reading.
  • Students use models to predict future outcomes in ocean systems.
  • Students use models to make predictions about how changes in nodes and/or edges can affect an ocean system.


Two 50-min periods for Model simulation and reading activity

Purpose: The purpose of this lesson is for students to practice the scientific process of using modeling to make predictions, to learn associated content, and to develop systems thinking. The two models used in the lesson are developed from current research on ocean acidification at the internal genetic level and the external ocean ecosystem level. Students should be guided in choosing the model activity, based on their interest and background knowledge. Lesson 5C modeling activities can be completed concurrently with the students’ data collection plan (Lesson 5A). Lesson 5C may also be taught independently following the completion of Lesson 5A.

Background needed: Knowledge of carbon and nitrate cycles and cell systems.

Lesson Sequence:

There are two available models and two scientific documents to interpret. With some initial scaffolding, the chosen activity should dovetail with the focus of their interest group.  All activities help students explore the question: What is happening to specific organisms, and the energy and resources they exchange, as part of the ocean system when CO2 levels rise?  For example, students who are measuring the change in mass of sea shells in marine water at various pH levels would benefit from the Ocean Acidification model. The Nutrient and Light model helps students explore changes in the diatom’s internal system when CO2 affects the resources available to them.


Day 1: Students start with using one of the models. Models are a tool used by scientists that help investigate changes observed through the process of analyzing scientific data. Science today is very collaborative. While all oceanographers are not able to go to Antarctica to directly analyze ice core samples, they are able to benefit from that data.  The data scientists record and share is freely available to scientists and the public alike and can be used to make models.

  • Step 1: Before Class use the “Download_NetLogo instructions” (see Resources for the model you choose), and save the NetLogo simulation model to a public folder for students to access. Hand out the instructions for students to download the NetLogo website and open the simulation model.
  • Step 2: Have students think first about what they predict will happen to shelled creatures as pH is altered in experimentation in Lesson 5A. (Experiments may still be in progress, but they should have an idea of the outcome). Ask students “When carbon dioxide levels rise what effect will the change in ocean pH have on not only shellfish and coral but also phytoplankton and the other organisms in the ocean ecosystem?” Then ask “How could the change in pH of the ocean affect students as they sit in their classroom?”
  • Step 3: Students will remember the role of phytoplankton in producing over 40% of the world’s oxygen. If the pH in ocean water brings about changes in population it affects where and how much carbon is available and also affects oxygen. But how? And how much? The models you are about to use can help make these connections and also predictions for the future. Each NetLogo simulation model could be approached from the same question: What are the mechanisms in ocean chemistry that can cause global shifts in carbon and oxygen? The worksheet for the model will ask you to change the carbon dioxide levels to test how acidity affects diatoms. The model is used to make predictions and to see the outcomes in phytoplankton (diatoms).

Day 2: The predictions they tested in the modeling activity are followed by integrating knowledge gained from a scientific reading on a particular scientific question. As further research brings new observations the dynamic nature of the models is revealed.

  • Step 4: Students participate in the close reading of a scientific article as a team. Assign students to groups of 2-4 to read together. They learn as they construct a more complete understanding of the reverberating effect to the ocean system network.
  • Step 5: Have groups discuss and report (using a network diagram) what they have found. This can be done as a round-robin, or as short presentations. (If time is short, this can be assigned as individual reading.) Throughout all steps, they are using scientific skills that help develop solutions that are a benefit to all. When a model is made, predictions of future outcomes can begin to take shape.

1 – Ocean Acidification Model and Guided Scientific Reading:


Phytoplankton are organisms responsible for over 40 percent of the total photosynthesis of the planet. They play a critical role in the global carbon cycle and ultimately in global climate. Use the model to deepen understanding of how carbon and pH might impact silica-shelled diatom and coccolithophore populations. The Ocean Acidification activity illustrates how changes in the system may affect the interactions among phytoplankton, nutrients, oxygen and carbon in the ocean system. Complete the OA_Model Investigation_ws_student worksheet using the NetLogo Ocean Acidification simulation model. Review what they learned– phytoplankton populations respond differently to changes in ocean pH. An important step is for students to see at what point the two populations switch places and one begins to recede and the other dominates as a population. This not only affects where and how much carbon is available it also affects oxygen and nutrients available in the ecosystem. But why? how? And how much? Assign groups of 2-4 to read one of the sections (A,B,C,D) in Blooming Diatoms: Ocean gardens a nutrient balancing act.pdf. Use the Close Reading guide_“Blooming diatoms…”ws_student to help students construct a system network diagram as they read. Depending on level, use Scientific Meaning_Building_Vocabulary. Each group discovers a different part of how nutrients and other changes to the system reverberate in the phytoplankton populations and the possible outcomes. And how what survives, in turn, affects earth’s oxygen producers. Have individual groups report what they have found. Combine what they learned to build a comprehensive group network diagram. Through this students gain broader understanding of the nodes’ effect on the populations of phytoplankton and the possible outcomes. (If time is short, this can be assigned as individual reading.)

NetLogo model-1: Ocean Acidification
Scientific reading jigsaw 1: Ocean Acidification

2 – Nutrient and Light Model and Guided Scientific Reading:


The Nutrient and Light model activity helps students explore how the internal changes in diatoms come about when CO2 affects the resources available to them. Students get a feel for how the amount of light and/or nutrients affect silica-shelled diatoms in an ocean system. The worksheet Nutrients, Light Effect on Diatoms Model ws-Student-2 is used to explore the model simulation. Next, the scientific reading “Diatom acclimation to elevated CO2 via cAMP signaling and coordinated gene expression” (see links below) help determine how ocean acidification affects one population. Students discover the key to why, under specific conditions, this is so. Focus on the question — If they do react differently in which conditions will the population increase or decrease? Begin by introducing the concepts of reading scientific papers with this short animated guide from Purdue Libraries: see Introduction-Purdue Libraries animation (teacher resource). Introduce the article “Diatom acclimation to elevated CO2 via cAMP signaling and coordinated gene expression”: (current research paper ) using current research paper-Intro for student jigsaw. Next, divide students into two groups and assign worksheets for current research paper-Results A for student jigsaw and current research paper-Results B for student jigsaw. The groups will report to each other what they find. Finally, use current research paper-discussion for student jigsaw At the end wrap up their findings with a discussion guided by current research paper-Whole Group for jigsaw wrap-up. Ask students to think: How does this reverberate throughout the ocean ecosystem affecting other populations and ultimately available oxygen and carbon?

NetLogo model-2: Nutrients and Light
Scientific reading Jigsaw-2: Nutrients And Light

You completed Instructional Activities. Please move to the Assessment tab for information on assessing your students’ learning.


How will I know they know?

  • Completed Worksheets and/or Notebook and Discussion Participation:
    • Were students able to appropriately and accurately complete their worksheets with thoughtful responses?
    • Were students able to appropriately participate in the discussion?  Consider a rubric or tally to track student involvement if necessary.
    • Were students able to complete the system network diagram, and connect the parts of the system together during the jigsaw?
    • Were students able to make a reasoned prediction about oxygen increases/decreases based on changes to the nodes of the system?

Mini-Surveys:  As part of our effort to ensure quality STEM learning experiences, we invite you to participate in short, but informative surveys. You can complete one, all or any variation between. Here is a downloadable Teacher Overview to guide you through all surveys.

  • A mini-survey is a short survey (1-3 minutes) that students and teachers will use several times over the course of the module. The questions are identical each time, so the same link can be used each time.
  • Student Mini-survey link (https://www.surveymonkey.com/r/OA_StudentSurvey). Please provide 2-4 minutes for students to complete the mini-survey while in class. It should take most students one minute or so, especially after the first survey or two (because the questions remain the same).
    • When prompting students to take this survey at this timepoint (#4), please remind students that this survey covers information taught over the entirety of Lesson 5 (which includes experimentation of 5a, and the supplemental materials found in 5b and 5c).  Here is an example prompt for students: Take this mini-survey while thinking of the lessons we completed on [Tuesday through Friday] that allowed you to:
      • work on your experiment,
      • use online data, websites, videos, and
      • use models to further explore and understand OA
    • Please complete the teacher survey while students are taking the mini-survey, or at the end of the day. Please take it on the same day the students take theirs (https://www.surveymonkey.com/r/OA_TeacherSurvey).
  • Here is the entire Survey Teacher Guide that you can use when implementing these surveys.  Thank you!


In this lesson, students are able to complete one modeling activity that is pertinent to them. If further scaffolding is needed select activities from Lesson 5B, such as the Global Carbon Atlas ws-Student (Global Carbon Atlas ws-Teacher) activity prior to attempting the Ocean Acidification model and prediction activity. This is an opportunity to accommodate each student’s needs. For students who need to explore things multiple times to internalize content, activities here with online data give them opportunities to learn things in different ways. For students who benefit from more content, at deeper levels, guide them to the Nutrient & Light Modeling activity and scientific paper “Diatom acclimation to elevated CO2 via cAMP signaling and coordinated gene expression” Gwenn M. M. Hennon1, et al.”

Students can have a difficult time grasping the connectedness of our land, atmosphere, and water.  This NASA model and video provide a way to visualize available data to help students understand the connectedness of an Earth with a disrupted carbon cycle.

For students who have little, or no chemistry background, this 4-minute NOAA video does a nice job explaining the basic chemistry in simple, pictorial terms:  http://www.youtube.com/watch?v=MgdlAt4CR-4

Extension Activities

Earth System Research Laboratory’s Global Monitoring Division website at NOAA  has real-time data for students to examine. NOAA’s Data Viewer is useful when looking at data trends. The Student Worksheet (Teacher Key) can help lead students to answer questions related to real-time data.

How do scientists get data? This video Inches of Snow and Tide is a good precursor to the data collection worksheet. The video from Olympic National Park discusses sea-level rise and climate change research. Minutes 10.00 to 13.00 show two scientists at work downloading a year’s worth of intertidal zone temperature data. The visual on the sensors, the STEM process and scientists getting their hands dirty are terrific examples. For more phenomenal videos of this sort, see WA SeaGrant’s page. Their 2020, Coast as Sentinel: Tribal Communities at the Forefront of Ocean Change video is especially powerful at showcasing the impact of OA in tribal communities.


Many teachers and scientists participated in the creation of these lessons and content.  Please view the list of credits for this work.