Water Planet Challenge

Dead Zones for Dinner

Introduction

Dead zones are formed as a result of an accumulation of nitrogen and phosphorus compounds which cause a process known as eutrophication. Nitrogen and phosphorus can be carried hundreds of miles from their source to dead zone areas where they are concentrated. The most famous dead zone in the United States is just off the coast of Louisiana. This portion of the Gulf of Mexico is just below the outlet of the Mississippi River. The nitrogen and phosphorus which causes the dead zone is the result of what happens in the areas which drain into the Mississippi River. Fertilizers used on crops and manure from livestock can both runoff into waterways where the nitrogen and phosphorus they contain contribute to algal blooms, eutrophication and dead zones.The Mississippi watershed drains most of the United States and that the area within this watershed is a major farming area contributing nitrogen and phosphorus which is concentrated in the Gulf of Mexico dead zone.

Objectives

1. Understand the causes and processes of eutrophication and their relation to the occurrence of dead zones.

2. Understand the methods for generating a map of dead zones in our oceans.

3. Determine the area of hypoxia, or low dissolved oxygen levels, off the coast of Louisiana, which is one of the most studied dead zones in the world.

4. Appreciate the scale of the dead zones.  The area of the dead zone determined in Objective #3 will be compared to areas of states in order to better visualize the scale the dead zone represents. 

5. Understand the limits of data and examine ways to improve the data sets.

6. Make predictions about the effects of other variables on the size of the dead zone.

Materials

• Photocopies of the student reading
• Photocopies of the student activity handout
• Photocopies or transparencies of 0.5 cm graph paper
• Colored pencils or markers in order to transfer the map area to the graph
• Calculators
• Computer with internet resources
• Library and/or classroom resources

Vocabulary

• Cellular Respiration - A chemical process that all living cells undergo that converts oxygen to carbon dioxide and releases energy to the organism and the surrounding environment.
• Dead Zone – A region of the ocean where most life is unable to survive because of inadequate dissolved oxygen, usually below 2 ppm O2.
• Dissolved Oxygen – The amount of oxygen gas that is dissolved in a unit of water. This is a standard indicator of an aquatic ecosystem’s health, and is measured in parts per million (ppm) or the equivalent unit of mg/l.
• Eutrophication – A process whereby excessive nutrient enrichment of an aquatic system leads to the system becoming oxygen-depleted.
• Hypoxic - When an aquatic system has less oxygen than that particular system requires to sustain itself, it is hypoxic or lacking in oxygen.
• Photosynthesis – A process that transforms the sun’s radiative energy into chemical energy and releases oxygen as a product.
• Phytoplankton – Single-celled organisms in open water that undergo photosynthesis and release oxygen to their environment.
• Runoff - Surface water that eventually flows into nearby rivers; it carries dissolved nutrients, sediments and other pollutants.
• Tributary - Any smaller branch of a river that drains into that river.
• Watershed - Total land area that a particular river system drains.

Key Questions

• What are dead zones and where are they located?
• How are dead zones formed?
• Why should we care that dead zones exist?
• How might what we eat be linked to the Gulf of Mexico?
• What are the environmental consequences to the dead zones?
• How can we prevent the formation of the dead zones?

Engage

1. Show a photo similar to this one and ask the students what they think it is and what they think might have caused it. (You may be able to find similar pictures from your own region by searching for “fish kill”+the name of your state or region.)? http://news.nationalgeographic.com/news/2010/09/photogalleries/100916-fish-kill-louisiana-suffocated-oil-pictures/

2. Show http://www.gulfhypoxia.net/Overview/hypoxia_flash.asp , a 15-second looping Flash video that describes the basics behind the creation of a dead zone. (This is from  http://www.gulfhypoxia.net/default.asp , a site that specializes in the Gulf of Mexico region that offers basic information regarding dead zones as well as links to information on other dead zones around the world)

3. Show the 5-minute video clip http://www1.coseecoastaltrends.net/modules/dead_zones/get_started/

4. Add any discussion questions that would be relevant.

Lesson Activity

1. Have students read “Dead Zones and Eutrophication: How Food We Eat Is Connected to Water Pollution” (Student Reading) and complete the mapping activity on the Gulf of Mexico Dead zone (Student Handout).

2. Have students complete the analysis questions at the end of the mapping activity.

3. Discuss their results and brainstorm ways the students could become further involved and educated about their local watershed and its connection to oceans.

Elaboration

Additional websites:
http://oceanservice.noaa.gov/education/tutorial_estuaries/media/supp_est10a_temp.html
http://oceanservice.noaa.gov/education/tutorial_estuaries/media/supp_est10d_dis.html
http://oceanservice.noaa.gov/education/tutorial_estuaries/media/supp_est10g_nutr.html
http://www.gulfhypoxia.net/Research/
http://www.gulfhypoxia.net/Research/Shelfwide%20Cruises/2011/SatelliteImage.pdf
http://science.howstuffworks.com/environmental/earth/oceanography/dead-zone1.htm
http://www1.coseecoastaltrends.net/modules/dead_zones/learn_about/
http://toxics.usgs.gov/definitions/hypoxia.html
http://toxics.usgs.gov/hypoxia/hypoxic_zone.html
http://www.gulfhypoxia.net/default.asp

Connections to National Science Content Standards, Grades 9-12

Life Science Content Standard C
The Interdependence of Organisms: Students will understand through example the interrelationships and interdependencies of organisms in ecosystems and destruction that can ensue when humans also interact with these ecosystems.
Matter, Energy, and Organization in Living Systems: Without the continuous addition of energy to an ecosystem, the ecosystem could not sustain their chemical and physical organization.  When our oceans experience a major disruption of their Chemical and Physical systems through input by humans, vast dead zones are the result.

Environmental Quality in Personal and Social Perspectives Content Standard F
Environmental Quality: Ecosystems provide services for humans in the form of clean oxygenated air, nutrient rich soils and clean water.  Students will have opportunities to study agricultural practices that are detrimental to ecosystems as well as practices that enhance the natural systems.  They will appreciate the many factors that can be impacted positively or negatively.
Science and Technology in Local, National and Global Challenges: By understanding how use of land resources by humans impacts marine organism even though they may be more than a thousand miles downstream, students can be a part of the imagination and innovations that can lead to solutions to this unintended impact.