This module was created to accompany “Understanding the Changing Planet” Chapter 1: How Are We Changing the Physical Environment of Earth’s Surface? Through the use of a free, online image analysis software called Image J, designed by the U.S. National Institute of Health, students will learn what role the geographical sciences have to play in understanding change in the Earth’s physical environment.
This activity should take a total of 45 to 90 minutes for your students to complete depending on the familiarity of your students with digital tools and excel. You can separate these activities into 40-minute segments, choose one of the two activities for a 15- or 20-minute experience, or you can assign the activities for homework. Your students will be able to freely obtain all tools necessary to complete these activities independently should you so choose for them to complete these on their own.
The student will be able to:
Prior to this activity, have the students do their own personal investigation:
Have you ever heard someone from an older generation, such as your grandparents, teachers or other mentors proclaiming what their surroundings were like when they were growing up? What things about the natural environment you remember hearing them say?
Have them write their answers/observations on the Student Answer Sheet.
At the beginning of the activity have students read the “How are we changing the Physical Environment of Earth’s Surface?” section to provide them with some background knowledge of the physical environment of Earth.
“Accelerated human modification of the landscape and human-driven climate changes are fundamentally altering Earth’s surface processes and creating ecological challenges that scientists and policy makers are struggling to address. The environmental impacts of human activity are expected to increase as the climate continues to warm and as the world becomes progressively more populated, industrialized, and urbanized.“ (UCP, 21) “Because natural processes vary spatially and across scales, a geographical perspective is essential to understanding their nature and character. The perspectives and tools of the geographical sciences used by geographers, geologists, ecologists, and others provide insights into soil erosion, flood magnitude and frequency, and ecological adjustments to climate change on both contemporary and paleotimescales.”(UCP, 22)
The Aral Sea exists as a closed basin fed by two rivers: the Syr Darya in the north and Daryu Amu from the south. The Lake itself was an economic asset to the central Soviet Union. At its peak, over 40,000 people were employed producing as much as 1/6 of Russia’s total fish catch. Several towns around its shores processed fish for export, trapped and tanned substantial furs for trade. Aral was the chief city at the delta of the northern river Syr. Moynoq is situated at the mouth of the southern Amu Daryu. The lake and its two large delta grass scrublands were an ecological refuge in the middle of mostly arid desert. Grain crops for food and fodder had been sustainably grown with sustainable irrigation for some time close to both rivers. As early as the 1930s, soviet collectivization of farms was underway and plans were being made to expand the type of goods grown by raising export crops in this arid climate. Starting in 1956 massive irrigation canals were dug and huge quantities of water were delivered to river valleys crops. By 1960 the largest single crop encouraged for growth was cotton. As typical for monocropping, fertilizers and pesticides have been applied regularly to keep up yields. Much of these percolate through the soils back to the river then into the Aral sea where they settle along with the rest of the sediments.
From the completion of the first canals in 1960 water levels started to drop. Towns such as Aral and Moynoq watched as their shoreline receded. At first they compensated by dredging canals themselves to reach the sea. By 1980 the salt in the remaining waters was toxic enough to diminish fish productivity by 75%. By the 1991 and the dissolution of the Soviet Union, all towns had given up on making a living from its waters, leaving their ships to beach on the dry sands. Water control would have to be coordinated between 5 new republics and the political will was just not there.
Local climate began to change. Without the water to absorb and hold heat, winters became colder and summers warmer and drier. As winds blew across the newly exposed sea floor, soils became airborne, spreading highly saline dust west over the towns and fields along the Syr Darya. Because of the years of pesticide and agrichemical use these salts were a toxic combination of chemicals! Croplands in the plume required more water to rinse the fields of the accumulating chemical fallout. With the rise of airborne dust, health of local citizens began to decline. Sore throats, allergies, and increases in cancer rates have appeared in local hospitals.
A regional council met to discuss problems and recommended many possible solutions after the fall of the Soviet Union. Below are listed but a few: An agreement to put aside 1% of the GDP of all nations in 1994 has as of this date resulted in no action. Rebuilding the inefficient leaky canals, lowering amount of land in agriculture, raising less water intense crops appropriate for these latitudes, using genetically engineered lower water demanding agricultural crops, redirecting neighboring rivers, or creating a canal from the Caspian to refill the basin with ocean water. By 2000 Kazakhstan recognized some of their dilemma and worked to dam the northern smaller Aral sea from the larger shallower waters in the south. While this worked well to stop the decline in surface area and reduce the salinity in these waters, it also deprived the southern portion of the more dependable output from the Syr Darya.
Instruct students that they will be exploring the Aral Sea region using the tool ImageJ that will aid them in understanding the change over time in the images. The images they are using span approximately ten years and they are tasked with figuring out how much area the Aral Sea covered in the first image compared with how much area the Aral Sea covered in subsequent images.
In this investigation of the Physical Environment Module, there are three parts.
Part 1: In this part, the students are required to use the basic navigation tools of the image processing software called Image J. They will learn to pan, zoom, and interpret the image information on an image screen.
Part 2: This part provides the students with ten images where they will learn how to measure the pixel data on the ten images provided that span the years 2000 – 2011.
Part 3: This part of the investigation requires the students to aggregate the image information they gather in Part 2 of the activity and to create a scatter plot of the data on Excel.
To conclude this investigation with the students, debrief them on what they learned about analyzing what happens on the physical Earth and the ramifications of the change of the Aral Sea over the past ten years.
All the Aral Sea images:
All data and maps in this lesson are to be used for educational purposes only. It is not to be used for research purposes.
Earth Observatory http://earthobservatory.nasa.gov/Features/WorldOfChange/aral_sea.php
American University Case Study
Authors: B. Duke, A. Palmer & R. Palmer