Part 1: The Practice of Science
In this series, educator Deb Greene walks us through some of the science on the ship. She explores the practices of science and how they fit in with the Next Generation Science Standards. Deb has taught and been involved in curriculum development in both the public and private sector. She currently works in the Curriculum and Instruction Department for the Anchorage School District in Alaska.
A Balancing Act: CO2 in the atmosphere and hydrosphere
Studying the marine environment is more than looking at salt and water.
The balance between carbon dioxide (CO2) in our atmosphere and oceans drives global climate. If we can better understand the relationship between the two, we’ll have a better grasp on how our planet works. And that is part of what the scientists on the Sikuliaq are out here to do.
Our seas are thriving with life and clues to the ever-changing environment as it strives to maintain a balance of CO2 between the atmosphere and the oceans.
As the scientific community studies the increased amount of CO2 in the atmosphere, we see a huge increase in CO2 in the marine environment. There is an equilibrium at the interface between air and water. This means that as more CO2 is released into the atmosphere from both natural and manmade sources, the oceans have the ability to draw down these molecules, ‘dumping’ the CO2 into the water. This is how oceans get the name of CO2 dumps or sinks.
The problem is, the oceans can only hold so much CO2 before the increased levels start to cause ecological changes in the seas. So the question then arises, how will the oceans handle all this CO2? Do the oceans have the ability to take this CO2, metabolize it or break it down chemically so that carbon can be packed away in the sediments and oxygen given off to support organic processes? And can this impact productivity in the marine environment, thus providing more food at the base of the food web? And if this can happen in our oceans, how does it happen? Is it biological in nature (i.e. is nitrogen being washed into our oceans at an increased rate from coastal areas as more organic matter is eroded away) or is it chemical in nature?
An example: Calcium Carbonate
A critical concern as more CO2 is absorbed by the oceans is that through a chemical process, the CO2 breaks apart and instead of the carbon being pulled out of circulation and buried as huge deposits eventually forming coal and oil, it breaks apart and chemically recombines with other elements to form a number of given compounds.
For example, calcium carbonate is used by oysters and other shellfish to make their shells. This means that the carbon remains active in the system, recombining as it is given off as a waste product and it never reaches the seafloor bottom to be buried.
As more atmospheric CO2 is drawn down into the water (the ocean and atmosphere maintain an equilibrium of CO2), the more bicarbonate is prevalent. As these break apart to form carbonates, it creates more acidic conditions. More acidic conditions dissolve the calcium carbonate that the organisms are synthesizing for shell material. This is a large area of research within ocean acidification. Herein lies a problem for any organism that makes its home in the protective covering of a calcium exterior (think crabs, clams, oysters, mussels, scallops, etc). More acidic conditions create a stressful living situation by impeding calcification. This may result in the organism becoming easier prey or, more likely, unable to sustain life and grow into reproductively viable mature organisms.
So, is the Earth able to adjust to these changes? Students in science classes learn that as animals respire, they breathe out CO2. We also know that as plants go through the photosynthetic process, they take in CO2 and release a by-product of oxygen. But CO2 is a product of other natural physical sources too. The balance is disrupted when the planet has more sources giving off CO2 than can be utilized by the ecosystem.
On the Sikuliaq, scientists are looking not only at the relationship between the atmosphere and the oceans, but also at the connections between the terrestrial (organic material/sediment runoff) and the marine environment. Is it possible that increased runoff from land in the Arctic due to rivers, increased glacial melt, permafrost melt, and coastline erosion may be contributing usable nitrogen into coastal waters from dissolved organic matter carried along these water systems? Could this nitrogen be added to the oceans to increase the productivity of marine phytoplankton and therefore break down carbon molecules that are contributing to ocean acidification? Or are organisms in the upper strata of the marine environment just breaking apart CO2 in the presence of sunlight?
Using a compilation of specialized equipment to collect sediment and water samples, scientists begin to unravel the mysteries of how the different spheres interact and respond to the changing climatic conditions planet Earth is experiencing.
Scientists using the Practices of Science
What has been taught in schools for generations as ‘the’ scientific method is a simplification of what scientists are doing on this research project.
As learning is facilitated in classrooms, teachers recognize that the world is changing fast and students of the 21st century are savvy in finding answers to most questions using their personal hand held devices. Opportunities in the science classroom expand with this seemingly infinite amount of information at student’s fingertips. The need for memorization of facts and figures has been pushed aside for a greater need to allow students to delve into the practices of science used by investigators seeking to understand the world in which we live.
Because scientists practice science, the Next Generation Science Standards (NGSS) has synthesized and outlined these practices to guide instruction as:
- Asking questions and defining problems
- Developing and using models
- Planning and carrying out investigations
- Analyzing and interpreting data
- Using mathematics and conceptual thinking
- Constructing explanations and designing solutions
- Engaging in argument from evidence
- Obtaining, evaluating, and communicating information
Teachers want students to be aware of the world around them and become global citizens. In an effort to prepare students for the 21st century, we need to encourage the growth of observant youth who can look at situations and begin asking focused questions in order to carry out investigations, build models, and construct explanations, and communicate their understandings.
Providing opportunities in coastal waters, local estuaries, even a creek side or pond close to the school is one of many ways to get students looking at our dynamic planet. The practices of science can be encouraged in all aspects of the sciences at all grade levels. The key is to engage students fully. Sitting on the ‘sidelines’ as the wonder of the world slips through their fingers raises no level of responsibility or caring for global citizenship.