The phenomenon of ocean acidification provides a great topic for the geography classroom, as it shows a clear link between an increase in atmospheric carbon dioxide levels and widespread environmental change. Here, as part of TES Geography Week, Jamie Buchanan-Dunlop explains how a trip to the Arctic got him thinking about ways to teach about ocean acidification:
It’s definitely colder near the glacier. We are in a small research vessel sampling the water of the Arctic Ocean towards the head of Kongsfjorden in the Norwegian archipelago of Svalbard. At 79 degrees north, the nearby town Ny Ålesund is the most northerly permanent settlement. Digital Explorer is here as part of a two-week live Arctic education event #FrozenOceansLive.
Joining us on the trip is Dr Helen Findlay of Plymouth Marine Laboratory, who has been studying ocean acidification in the polar regions for many years.
Ocean acidification is the process by which atmospheric carbon dioxide is absorbed into the oceans and increases ocean acidity through chemical processes. The change is felt most keenly in the cold waters of the polar seas.
When I taught geography, it never struck me that the structure of the curriculum almost entirely ignored the oceans. Our oceans cover 72 per cent of the planet’s surface, provide 50 per cent of the oxygen we breathe, regulate the climate, are the number one source of protein for one billion people and, with the help of a new curriculum, are now slowly creeping into geography classrooms.
Ocean acidification in a region such as the Arctic can fit into many topic areas: extreme environments, human impact, environmental change and more. The basic concepts can be taught in a relatively easy way and data sets and current research are readily available to bring the topic to life.
The study of carbon dioxide emissions mostly focuses on atmospheric impact. Yet there is 50 times as much carbon in the oceans as in the atmosphere. Since the industrial revolution, the rapid increase in atmospheric carbon dioxide has been having a significant impact on ocean chemistry.
The average ocean pH has dropped from pH 8.2 to pH 8.1 over the past 250 years. This may seem like a small amount, but it represents a 30 per cent increase in ocean acidity. Current models indicate that the average ocean pH will drop further to pH 7.8 by the end of this century.
The best longitudinal data linking atmospheric carbon dioxide, ocean carbon dioxide and ocean pH is from the Hawaii Ocean Time-series.
The Arctic acts as a bellwether for acid levels in our seas and their impact on the marine ecosystem, because acidification is thought to happen here faster than anywhere else.
Dr Findlay explains: “Within only a few decades, an increase in ocean acidity may impact the health and abundance of the smaller marine creatures that are so numerous in our ocean ecosystems, with potentially serious consequences for both them and the larger marine fish and mammals that rely on them for food.”
In teaching ocean acidification in the geography classroom, there are a number of steps:
1.) Provide an overview of the issue, as the topic may be unfamiliar to many students.
A good introductory video has been made by the National Resource Defence Council and another by Plymouth Marine Laboratory.
2.) Cover some of the basic concepts and processes behind ocean acidification.
This could be as simple as adding a pH indicator to still and sparkling water and looking at the difference. You may have to talk to the science department to borrow some pH indicators and might even get brownie points for your cross-curricular endeavours!
3.) For Key Stage 3 students, look at possible impacts on the marine food web.
Details of an Arctic food web lesson can be found in the Frozen Oceans Key Stage 3 geography booklet, including the classic experiment of putting shells in vinegar.
4.) For GCSE classes, conduct a data case study.
You can use the Frozen Oceans GCSE geography booklet, which includes a data case study containing an Excel spreadsheet as well as offline versions of over 20 years of ocean acidification data from the Pacific.