The Chesapeake The Chesapeake Bay’s “Dead Zone”Bay’s “Dead Zone”

Created by Jeff DeHartCreated by Jeff DeHart

October 2007October 2007

The Chesapeake Bay:The Chesapeake Bay:A Little Bit of BackgroundA Little Bit of Background

•The Chesapeake Bay The Chesapeake Bay is North America's is North America's largest estuary (an largest estuary (an area where fresh and area where fresh and salt water mix) and salt water mix) and the world's third the world's third largest. largest.

• The Chesapeake Bay The Chesapeake Bay watershed watershed encompasses parts encompasses parts of six states: of six states: Delaware, Maryland, Delaware, Maryland, New York, New York, Pennsylvania, Pennsylvania, Virginia, and West Virginia, and West Virginia as well as Virginia as well as the District of the District of Columbia. Columbia.

• The watershed The watershed covers 64,000 covers 64,000 square miles and is square miles and is home to about 17 home to about 17 million people. The million people. The population is population is expected to increase expected to increase to more than 18 to more than 18 million residents by million residents by 2020.2020.

The History of the BayThe History of the Bay•The Chesapeake Bay was formed about The Chesapeake Bay was formed about 12,000 years ago when glaciers melted 12,000 years ago when glaciers melted and flooded the Susquehanna River and flooded the Susquehanna River valley. valley. •The archeological record shows that The archeological record shows that humans have lived in the watershed humans have lived in the watershed since 8,000 B.C. Mammoth, mastodon, since 8,000 B.C. Mammoth, mastodon, bison, elk, camel, horse, and peccary bison, elk, camel, horse, and peccary roamed the Chesapeake watershed roamed the Chesapeake watershed during this era. during this era. •The name Chesapeake is derived from The name Chesapeake is derived from the Native American word the Native American word "Tschiswapeki" meaning "great shell fish "Tschiswapeki" meaning "great shell fish bay." bay."

Facts About the BayFacts About the Bay• The Chesapeake Bay watershed The Chesapeake Bay watershed

supports more 3,600 species of plant supports more 3,600 species of plant and animal life, including about 350 and animal life, including about 350 species of fish. species of fish.

Facts continued…Facts continued…• From north to south, the Bay is roughly 200 From north to south, the Bay is roughly 200

miles long. miles long. • The narrowest part of the Bay is 3.4 miles at The narrowest part of the Bay is 3.4 miles at

Aberdeen, Maryland. It is four miles wide near Aberdeen, Maryland. It is four miles wide near Annapolis, Maryland, and it is the widest near Annapolis, Maryland, and it is the widest near the mouth of the Potomac River - 35 miles. the mouth of the Potomac River - 35 miles.

• The Bay has an average depth of 21 feet. The Bay has an average depth of 21 feet. There are a few deep holes that are more than There are a few deep holes that are more than 170-feet deep, including "The Hole" that is 170-feet deep, including "The Hole" that is 174 feet deep and located off Bloody Point, 174 feet deep and located off Bloody Point, Maryland. Maryland.

• The Bay has more than 11,600 miles of The Bay has more than 11,600 miles of shoreline, including all tidal wetlands and shoreline, including all tidal wetlands and islands. That's more shoreline than the entire islands. That's more shoreline than the entire West coast of the United States. The vast West coast of the United States. The vast majority of shoreline is privately owned.majority of shoreline is privately owned.

• The Chesapeake Bay is a valuable The Chesapeake Bay is a valuable resource for us humans as well!resource for us humans as well!

• But there is a slight problem occurring But there is a slight problem occurring in the bay…in the bay…

WARNING!WARNING!

You are about to enter…You are about to enter…

The DEAD The DEAD ZONEZONE

Imagine what life would be like, if for months at a time the air we breathe contained very little oxygen…

or NO oxygen at all!

The Chesapeake The Chesapeake Bay’s “dead zone,” Bay’s “dead zone,” which stretches for which stretches for hundreds of square hundreds of square miles during the miles during the summer, has too little summer, has too little oxygen to support a oxygen to support a healthy ecosystem.healthy ecosystem.

• The dead zone The dead zone affects affects approximately 40% approximately 40% of the Chesapeake of the Chesapeake Bay’s main stem.Bay’s main stem.

• Starting at the Starting at the Patapsco River Patapsco River near Baltimore, the near Baltimore, the dead zones dead zones extends more than extends more than 100 miles south to 100 miles south to York River, near York River, near Hampton Roads, Hampton Roads, Virginia.Virginia.

• Low dissolved oxygen (DO)Low dissolved oxygen (DO) levels, levels, called called hypoxiahypoxia, can affect the growth , can affect the growth and reproduction as well as the and reproduction as well as the health of the Chesapeake’s living health of the Chesapeake’s living resources.resources.

• Some areas have no oxygen at all Some areas have no oxygen at all and are called and are called anoxicanoxic. Anoxic waters . Anoxic waters will kill most aquatic animals.will kill most aquatic animals.

Like animals on land, nearly all of the Like animals on land, nearly all of the Chesapeake Bay’s aquatic life depend on Chesapeake Bay’s aquatic life depend on oxygen to survive, oxygen to survive,

to perch and striped bass above to perch and striped bass above

and underwater grasses in betweenand underwater grasses in between

from worms and crabs on the bottomfrom worms and crabs on the bottom

Cause and EffectCause and Effect• Low dissolved oxygen levels in the Bay are a Low dissolved oxygen levels in the Bay are a

result of nutrient pollution, mainly nitrogen result of nutrient pollution, mainly nitrogen and phosphorous.and phosphorous.

• Nitrogen and phosphorous wash into the water Nitrogen and phosphorous wash into the water from fertilized farm fields, gardens, and lawns.from fertilized farm fields, gardens, and lawns.

• Chemical fertilizers from factories and Chemical fertilizers from factories and automobile exhaust bond with water droplets automobile exhaust bond with water droplets in clouds and fall back into the Bay with rain in clouds and fall back into the Bay with rain showers.showers.

• Human sewage from sewage treatment plants Human sewage from sewage treatment plants also enters the Bay, adding more nutrients.also enters the Bay, adding more nutrients.

Cause and Effect Cause and Effect continued…continued…

• This nutrient pollution in the Bay This nutrient pollution in the Bay causes huge algal blooms (algae).causes huge algal blooms (algae).

• When this algae dies, it sinks to the When this algae dies, it sinks to the bottom of the Bay and then starts to bottom of the Bay and then starts to decompose. During decomposition, decompose. During decomposition, bacteria work overtime to eat the bacteria work overtime to eat the decaying algae, using up the oxygen decaying algae, using up the oxygen supply. supply.

• This decomposition process removes This decomposition process removes oxygen from the water, making it oxygen from the water, making it extremely hard for organisms to extremely hard for organisms to survive.survive.

August, 2007August, 2007

Algal bloom near Algal bloom near

Hampton, VAHampton, VA

June, 2007June, 2007

Close up of the leading edge Close up of the leading edge of a red algal of a red algal

bloom at the mouth bloom at the mouth of the Potomac Riverof the Potomac River

The Problem in the The Problem in the MainstemMainstem

• In the deep waters of the Chesapeake Bay, In the deep waters of the Chesapeake Bay, the decomposition of algal blooms causes the decomposition of algal blooms causes anoxia or hypoxia during much of the anoxia or hypoxia during much of the summer. summer.

• The bottom areas of the Bay suffer from The bottom areas of the Bay suffer from these low dissolved oxygen levels for these low dissolved oxygen levels for roughly 10 months out of the year.roughly 10 months out of the year.

• The dead zone can also reach into shallow The dead zone can also reach into shallow waters, hurting habitat and forcing fish waters, hurting habitat and forcing fish and crabs to leave the area. Many fish and crabs to leave the area. Many fish and crabs are unable to leave these areas and crabs are unable to leave these areas and have died as a result.and have died as a result.

June, 2007June, 2007

Fish Kill near Fish Kill near Weems Creek, MDWeems Creek, MD

September, 2007September, 2007

Fish Kill in Fish Kill in

South River, MDSouth River, MD

What can we do?What can we do?• The best thing we can do to help solve the low The best thing we can do to help solve the low

dissolved oxygen problem is to address nutrient dissolved oxygen problem is to address nutrient pollution of the Bay.pollution of the Bay.

• We need to reduce nitrogen pollution from We need to reduce nitrogen pollution from farmland runoff, vehicles and power plants and farmland runoff, vehicles and power plants and sewage treatment plants.sewage treatment plants.

• Restoration of the Bay’s natural defense Restoration of the Bay’s natural defense systems such as forestlands, wetlands, oysters, systems such as forestlands, wetlands, oysters, and underwater grasses will help the Bay and underwater grasses will help the Bay protect itself. These natural features of the Bay protect itself. These natural features of the Bay will help to filter nutrients and sediment from will help to filter nutrients and sediment from bay water and rainfall.bay water and rainfall.

• Spread the word about the importance of the Spread the word about the importance of the Chesapeake Bay!Chesapeake Bay!

Images courtesy of:Images courtesy of:www.nationalgeographic.com

www.cbf.orgwww.cbf.org

www.fws.govwww.fws.gov

www.audubon.orgwww.audubon.org

www.outdooralabama.comwww.outdooralabama.com

www.dnr.metrokc.govwww.dnr.metrokc.gov

www.olesouthusa.comwww.olesouthusa.com

www.mcintoshcounty.comwww.mcintoshcounty.com

www.visitannapolis.comwww.visitannapolis.com

www.bobrooks.comwww.bobrooks.com