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Atmosphere, Biosphere, Climate, Energy, Geosphere, Hydrosphere, Oceans



It is estimated that humans have put 244 billion metric tons of carbon dioxide in the Earth's Atmosphere. The carbon dioxide comes from the burning of fossil fuels and the making of cement. The atmospheric concentration of carbon dioxide has risen from the pre-industrial 280 parts per million to the current 402.80 parts per million. For some time, scientists had been trying to determine where the extra carbon dioxide from humans emissions went. Fortunately, it turns out, the oceans serve as a major sink in absorbing carbon dioxide. National Geographic (2004) summarized prominent researchers' findings that oceans absorb half of all man-made carbon dioxide. The question is whether the oceans can continue to scrub the air of carbon dioxide. Is there a limit?

A concern is that the current rate of warming and acidification is faster than Earth has ever experienced. "Because carbon dioxide is an acid, ocean surface pH is falling," (pH is a measure of acidity in solutions) said Richard Feeley, a marine chemist with NOAA. The increased acidity makes growth more difficult for corals, plankton and other invertebrates. Marine life find it difficult to create calcium carbonate shells in the highly acidic water.

One geoengineering solution to increased atmospheric carbon dioxide is the idea of deliberate carbon sequestration in the deep ocean. Strategies for storing excess carbon dioxide in the oceans include enhancing the growth of carbon-fixing (i.e. photosynthesizing) organisms or injecting carbon dioxide directly into the deep ocean. In the first case, one suggested approach is to seed the oceans with iron (a nutrient) to increase the growth of phytoplankton. The hypothesis is that the phytoplankton would then bloom, extracting carbon dioxide from the ocean/atmosphere during photosynthesis, and would eventually sink to the seafloor taking much of the fixed carbon with them.



Basic: Your state senators have requested that your group brief them on the impact of increased ocean dissolved CO2 concentrations. Your ESS analysis will play a key part in your senators' plans for ocean-related research initiatives. You have available to you NOAA's Ocean Acidification Observations and Data to assist in your research.

Comprehensive: Geoengineering has been suggested as one possible solution for reducing atmospheric CO2. Because of your group's interest in ocean acidification, you have been asked to analyze the impacts of ocean-based geoengineering proposals on the specific problem of ocean acidification. Your task will be to choose a specific geoengineering proposal, perform an ESS analysis on that proposal and provide feedback to policy makers on how that geoengineering proposal will impact ocean acidification.


Date: 10/26/2011

Scenario Images:

Ocean Carbon Connections
Ocean's Role in Carbon Cycle Click here for larger graphics and more climate change information. Credit Philippe Rekacewicz, UNEP/GRID-Arendal.

For more climate related graphics, go here.


"The figure shows the changes in surface ocean (50 m) chemistry at the Hawaiian Ocean Time-Series over the last 20 years. The top panel shows a decline in carbonate ion concentration, the middle panel shows a trend of decreasing pH, and the bottom graph shows a concomitant CO2 increase in the water and the atmosphere."

Credit NOAA.



NOAA Introduction to Ocean Acidification (Cycle A)
The rate of CO2 concentration increase in the atmosphere has been faster in the past two hundred years than at any time in the past 650,000 years. "The global oceans are the largest natural reservoir for much of this excess CO2, absorbing approximately one-third of that attributed to human activities each year [Sabine et al., 2004]."


NOAA, NSF USGS: Impacts of Ocean Acidification on Coral Reefs (Cycle A)
Impacts of Ocean Acidification on Coral Reefs
and Other Marine Calcifiers: A Guide for
Future Research. A report from a workshop sponsored by the National Science Foundation, the National Oceanic and Atmospheric Administration, and the U.S. Geological Survey.


NOAA: New Study Details Ocean Acidification in the Caribbean (Cycle A)
"A new study, which confirms significant ocean acidification across much of the Caribbean and Gulf of Mexico, reports strong natural variations in ocean chemistry in some parts of the Caribbean that could affect the way reefs respond to future ocean acidification."


PMEL (NOAA) Ocean Acidification Home Page (Cycle A)
A series of links to the Pacific Marine Environmental Laboratory (PMEL) and NOAA research articles and sites to Ocean Acidification. See also this link to PMEL's CO2 Program.


Scripps Institution of Oceanography: "Acidic Ocean: Why Should We Care?" (Cycle A)
"The ocean absorbs almost half of the carbon dioxide emitted by human activities, changing its chemistry in ways that may have significant effects on marine ecosystems. Join Scripps marine chemist Andrew Dickson as he explains what we know --- and what we don't --- about this emerging problem." (video lecture on the topic)


Seawater, Sea Urchins and Stress (Cycle A)
How does ocean acidification impact sea life? From the American Museum of Natural History, scientist Gretchen Hofmann analyzes global warming's impact on sea urchins.


The Carbon Cycle and How It Influences Climate (Cycle A)
From the American Museum of Natural History. "The long-term carbon cycle involves the movement of carbon between the solid Earth and the ocean and atmosphere...This carbon, which ends up mainly in the form of bicarbonate ions (HCO3-) along with ions of calcium and other elements dissolved in river water, eventually washes in the ocean."


CO2 Figures May Point Toward A Need for Geoengineering (Cycle B)
New Scientist article in May 2009 states: "The amount of carbon dioxide absorbed by plankton in the world's oceans is far less than previously thought, according to a first-of-its-kind global ocean health assessment.

The study, which relied on satellite imagery to measure plankton productivity, suggests current estimates of C02 absorption are off by more than 2 billion tons, or 4 per cent, per year."


Ecosystem Impacts of Climate Change and Ocean Acidification (Cycle B)
Ocean acidification from the European project on Ocean Acidification (EPOCA). "Climate change causes ocean warming and acidification on global scales. In contrast to well established effects of warming, evidence for the effects of rising carbon dioxide (CO2) on marine ecosystems is only just emerging. However, future scenarios indicate threats to marine life through combinations of rising CO2, warming and more frequent hypoxia events."


How Long Can the Ocean Slow Global Warming? (Cycle B)
A very pertinent article from the Woods Hole Oceanographic Institute: "The oceans have slowed greenhouse warming by absorbing excess heat-trapping carbon dioxide from the atmosphere. But how much can we depend upon the ocean to continue to act as a brake on ever-accumulating CO2 in the future? And will the buildup of CO2 in the ocean change its chemistry, making it more acidic and threatening marine life?"
See also:
Ocean Acidification: A Risky Shell Game.


Pulse of the Planet (comprehensive) (Cycle B)
Taking the Pulse of our Changing Planet: A public lecture and professional development series at Liberty Science Center. From Rutgers University: "What happens to the carbon dioxide introduced by fossil fuels into our world's atmosphere? Estimates are that half of all carbon dioxide produced by humans since the industrial revolution has dissolved into the world's ocean. These increased inputs of carbon dioxide are changing the ocean today and are affecting the ocean's chemistry and the organisms that call it home."

This site contains many carbon related links, plus geoengineering and ocean acidification.


U.S. Global Change Research Program (Cycle B)
Search on "Ocean Acidification" to get an expanded set of documents.


UNESCO-Intergovernmental Oceanographic Commission Webpage on the Ocean (Cycle B)
"In May 2004, the Scientific Committee on Oceanic Research (SCOR) and the Intergovernmental Oceanographic Commission of UNESCO (UNESCO-IOC) co-hosted an international symposium, "The Ocean in a High-CO2 World", to evaluate what is known about these issues. This symposium brought together 120 of the world's leading scientists from 18 countries with expertise from different branches of marine biology, chemistry and physics to piece together what is known about the impacts of ocean acidification on marine ecosystems, and to identify urgent research priorities to understand the mechanisms, magnitude and time scale of these impacts." Click here Click here for another set of links to this symposium. This site provides the program and abstracts to this symposium.


Acid Test: The Global Challenge of Ocean Acidification (Cycle C)
"ACID TEST, a film produced by the Natural Resources Defense Council (NRDC), was made to raise awareness about the largely unknown problem of ocean acidification, which poses a fundamental challenge to life in the seas and the health of the entire planet. Like global warming, ocean acidification stems from the increase of carbon dioxide in the earth's atmosphere since the start of the Industrial Revolution."

A video well worth watching; don' miss it. The site has links to research and related material.


Classroom Video on Ocean Acidification (Cycle C)
From ABC Australia, a video on ocean acidification.


Ocean Literacy Principles (Cycle C)
"An understanding of the oceans influence on you and your influence on the ocean." contains links to the Ocean Literacy Principles.


Video from National Resources Defense Council (Cycle C)
This is a visibly appealing, well done video narrated by Sigourney Weaver with spots from scientists. This would be a good introduction to a class or PBL on ocean acidification.


Sample Investigations:


Concept Map Builder (Cycle A)
Go to the COSEE concept map builder for a tool that will assist your study of science, e.g., global climate change or ocean science.
Difficulty: beginner


Coral Sand and Vinegar: Investigating Ocean Acidification (Cycle A)
An activity with vinegar to demonstrate concepts involved in ocean acidification.
"...increased levels of carbon dioxide in the atmosphere are resulting in global climate change and an accompanying sea level rise. Global climate change is a serious problem, but it's not the only problem caused by excess CO2. When human activities put excess CO2 in the atmosphere, some of this CO2 gets absorbed in the ocean. In the ocean, CO2 combines with water (H2O) to form carbonic acid (H2CO3)."
Difficulty: beginner


Marine Scientist Abby Smith Discusses Ocean Acidification (Cycle A)
Our oceans are absorbing about one-third of the carbon dioxide in the atmosphere. As a result, they are becoming more acidic. Associate Professor Abby Smith, from the University of Otago, is researching the role that bryozoans can play in monitoring these changes in pH. Includes a video to show your students about curiosity in science and Dr. Smith's research into the impacts of ocean acidification.
Difficulty: beginner


NOAA's Coral Reef Watch and Ocean Acidification (Cycle A)
This site contains NOAA visualizations on ocean acidification in the Caribbean. Watch the time series and check the charts for levels associated with CO2 and other variables. See also this animation from the NOAA Environmental Visualization Laboratory on ocean acidification. This site also has five images showing model output of ocean acidification from the years 1765 to 2100. (be sure to type "ocean acidification" into the search prompt box.)

Difficulty: beginner


Acid Ocean Lab (Cycle B)
An online virtual lab to research the impacts of Ocean Acidification. Be sure to click far enough in the slides to get to the lab.
Difficulty: beginner


Monterey Bay Aquarium Research Institute Iron Fertilization Activities (Cycle B)
"This Web slide show will take students step-by-step through the processes that are involved the biological pump. Students will be encouraged to think about how the pump will react to various changes in the environment, and how availability of nutrients such as nitrate and iron affect the amount of carbon dioxide that is eventually sequestered in the deep oceans."
Difficulty: beginner


Ocean Acidification: High School (Cycle C)
From NOAA, a series of lessons and demonstrations on Ocean Acidification.
Difficulty: beginner


Understanding Ocean Acidification (Cycle C)
"These hands-on activities will help you demonstrate and explore the effects of increasing carbon dioxide on the acidity of the ocean and learn about impacts an acidic ocean has on marine organisms, the ocean food web, and humans."
Difficulty: beginner




  • Science
    National Science Education Standards - Science Content Standards The science content standards outline what students should know, understand, and be able to do in the natural sciences over the course of K-12 education.
      The understandings and abilities associated with the following concepts and processes need to be developed throughout a student's educational experiences:
      • Systems, order, and organization
      • Evidence, models, and explanation
      • Constancy, change, and measurement
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