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Chesapeake Bay Water Pollution


Virginia Carter, Stan Koller, Peter W.Bergstrom and Robert A. Batiuk. Assessing ... Fayer, Ronald, Earl J. Lewis, James M. Trout, Thaddeus K. Garczyk, Mark C. ... – PowerPoint PPT presentation

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Title: Chesapeake Bay Water Pollution

Chesapeake Bay Water Pollution
  • Rob Douglas
  • John Misamore

Geography of the Chesapeake Bay
  • The largest and most complex estuary in the
    continental United States
  • Its drainage basin encompasses 64,000 square
  • Its main stem stretches 190 miles from the
    head at the Susquehanna flats in MD to the mouth
    in tidewater VA where it meets the Atlantic

Chesapeake Bay-The Problem
  • The bay operates at about one quarter of its
    potential due to water pollution.
  • The bay has lost about 98 of its oysters, 90
    of its grasses and 50 of its buffers.
  • The health of the bay is maintained by natural
    filtering mechanisms that have been destroyed in
    the past several years.

Types Of Pollution
  • Nitrogen and Phosphorus are most problematic to
    the bay
  • Nitrogen causes algae blooms which reduces the
    amount of dissolved oxygen
  • Algae also blocks out sunlight inhibiting
    underwater grasses.
  • Approximately 300 million pounds of nitrogen
    enters the bay every year.

How water quality is measured
  • Bay water quality is given a point value based on
    a 100 point scale.
  • The scale is based on John Smiths records of the
    bay during the 1600s.
  • A score of 100 describes what John Smith
  • His records indicate that during the 1600s reefs
    were a threat to navigation.
  • The bay is believed to have been operating at
    its full potential during the time John Smith

So how bad is it?
  • In the 2003 State of The Bay report the bay
    scored a 26 out 100.
  • Water quality was at its lowest in 1983 when the
    bay reached a low of 23.
  • A rating of 70 is considered to be healthy.

Water Quality Ratings
  • Habitats
  • Wetlands-42
  • Forest Buffers-54
  • Underwater Grasses-12
  • Resource Lands-30
  • Fish
  • Crabs-40
  • Rockfish-75
  • Oysters-2
  • Shad-7

Water Quality-Pollution
  • Toxics-28
  • Water Clarity-16
  • Phosphorus-16
  • Nitrogen-16
  • Dissolved Oxygen-15

Where is it coming from?
  • Most common cause is from human sources
  • Agriculture, smoke stacks, septic systems,
    roadways and water treatment plants
  • Agriculture contributes to 40 percent of Nitrogen
    and 50 percent of phosphorus runoff.
  • ExampleOn the eastern shore chickens outnumber
    people 10001

Acid Rain Affecting the Bay
  • Threatens marine life by acting as a fertilizer
  • Accounts for 1/4 of the nitrogen load in the
    Chesapeake Bay
  • contributes as much as point sources like raw
    sewage and industrial plants
  • Congressional action has taken place to control
    acid rain (the National Acid Precipitation
    Assessment Program or NAPAP)

Cause and Effect of Acid Rain
  • Causes
  • Emissions from cars, trucks and midwestern
  • Effects
  • increases acidity of water
  • acts as fertilizer to promote algal growth that
    causes oxygen depletion in the bay
  • dead zones of no oxygen kill plant and other
    marine life

The Role of Phytoplankton
  • To grow, phytoplankton need nutrients. Nutrients
    found on fertilizers are the most helpful in
    phytoplankton growth.
  • When runoff from surrounding farms and new
    construction enter the bay and its river systems
    it promotes phytoplankton growth.
  • This problem is of course becoming more and more
    apparent as the population in Maryland and its
    surrounding states grow and cause more
    construction and runoff into the bay and its
    river systems
  • The Chesapeakes estuary make-up also promotes
    phytoplankton growth because the freshwater
    circulation brings nutrients and affects the
    bays salinity.

Climate Changes
  • High levels of flow from tributaries creates
    stratification in the bay.
  • Dense ocean water sinks to the bottom and becomes
  • Climate winds can push anoxic waters into the
  • A proven link between climate changes and water
    quality would mean that changes in water quality
    could be predicted months in advance.

Effects of Pollution Runoff from Rain
  • Adversely affect the underwater bay grasses that
    support a great variety of bay life
  • High levels of nitrogen and phosphorus accumulate
    in watershed to contribute to the algae bloom
  • Algae in shallow waters of the Chesapeake Bay
    block out light in the daytime and starve the
    water of dissolved oxygen at night
  • When algae dies it washes into deeper waters and
    decomposes and reduces the oxygen amount even
  • Low oxygen levels are hurtful to other aquatic
    life (crabs and fish)

Seasonal Changes Effect the Water Too
  • Late winter and early spring
  • the period of highest freshwater flow
  • nitrogen-rich non-point sources (runoff) from the
    land is high and causes increasing nitrogen
  • there is a net flux of phosphorus from the water
    to the sediments because of the settling of
    phosphorus-containing particles.
  • Oxygen levels increase due to low biological
    activity and cold water temperatures which favor
    phosphorus accumulation
  • Late spring and early summer
  • runoff decreases as well as nitrogen input
  • as water temperature increases the metabolism of
    organisms in the sediments increase and the
    concentration of oxygen in the water decreases
  • Phosphorus amounts are also low

Seasonal Changes Effect the Water Too (cont.)
  • Late summer and early fall
  • oxygen is severely depleted from both the water
    column and the sediments
  • under conditions of low oxygen concentration the
    liberation of phosphorus by chemical processes is
  • the nitrogen concentration remains low enough to
    limit the growth of phytoplankton that are
    obligated to use bound nitrogen
  • Late fall and early winter
  • nitrogen concentration decreases with the
    decrease in amount of nitrogen-enriching runoff
  • phosphorus increases due to environmental
    sediment accumulation

Spring Showers do not bring May flowers
  • The heavy amounts of rain from the spring of 2003
    hurts the aquatic life more than it helps it
  • Sent large amounts of pollutants into waterways
    from New York to Virginia all to end up in the
    Chesapeake Bay
  • Fertilizers, sewage, sediments and garbage were
    all carried downstream with the increased rains
    adversely affecting the Bay
  • This increased runoff also brings amounts of
    nitrogen and phosphorus nutrients as well that
    cause increases in phytoplankton production

  • The Choptank River
  • the largest tributary on the eastern shore of the
    Chesapeake Bay
  • approximately 15,000 ha was vegetated with Ruppia
  • around 1 of the Choptank River is less than 2m
  • The York River
  • in 1971 there was an abundance of submersed
    aquatic vegetation along the shoals of the river
    covering around 820ha.
  • There has been a decline in this since the 70s
  • Since 1990 a significant regrowth has occurred in
    the downriver areas leaving the upriver area
    still unvegetated
  • Approximately 15 of the York River is less than
    2m deep which is covered in submersed aquatic

Cryptosporidium parvum oocysts
  • What is it?
  • A zoonotic waterborne pathogen
  • Where does it come from?
  • Human, wildlife, pets and livestock feces that
    enters surface waters through wastewater, leaky
    septic tanks or runoff
  • What is its effect on the Chesapeake Bay?
  • Can be retained on gills and in hemolymph of
    oysters in the bay and causes them to be
    infectious to humans

Deadly Oysters being tested
  • Tests have found these infected oysters in all
    seven commercial oyster harvesting sites sampled
    in the Chesapeake Bay
  • locations were from the Wicomico River, Nanticoke
    River, Fishing Bay, Potomic River, Patuxent
    River, and two locations on the Tangier Sound
  • 30 oysters were examined from each site and the
    gill tissue and hemolymph were washed and dried
    and made into slides to look for green
    fluorescing walls. The pooled hemolymph and gill
    washings were given to mice to test for
    infectious affect.
  • The concentrations of oocysts at each site ranged
    from 8-79oocysts/L with a mean of 32oocysts/L.

What did the results say about these oysters?
  • The tests concluded that bivalve mollusks can
    effectively remove and retain oocysts of
    Cryptosporidium from feces-contaminated estuarine
  • Only human and bovine genotypes of
    Cryptosporidium parvarum were recovered from the
    oysters tested.
  • These findings indicate that water at these
    oyster harvesting sites contained human or animal
    feces when oysters were filtering and that
    oocysts excreted in those feces were acquired by
    the oysters. Because they can be infectious for
    humans you need to cook oysters at above 72C to
    render it noninfectious, or freeze at -20 C .
    Cooking is recommended over freezing.

The Chesapeake Bay and Submersed Aquatic
  • What is it?
  • Rooted flowering plants that have colonized
    primarily soft sediment habitats in coastal,
    estuarine, and freshwater.
  • What kinds are found in our bay?
  • Both marine angiosperm and freshwater
    macrophytes. They have been one of the
    contributing factors to the high productivity of
    the Chesapeake, especially the abundance of
  • What does it do?
  • Provides food for waterfowl and critical habitat
    for shellfish and finfish. It also affects
    nutrient cycling, sediment stability and water

Whats wrong with the Aquatic Vegetation?
  • There has been a decline in submersed aquatic
    vegetation since the 1960s -70s.
  • This decline was related to increasing amounts of
    nutrients and sediments from development of the
    bays shoreline and watershed
  • There are approximately 25,000 ha of submersed
    aquatic vegetation in the Chesapeake which is
    only 10 of the historical distribution

What is needed for survival?
  • It requires light for photosynthesis, growth,
    survival and depth penetration.
  • The maximum depth at with submersed plants can
    survive increases with increasing light
  • This is measured with a Secchi disc. This black
    and white disc is dropped into the water as far
    as it can be seen. When it can no longer be seen
    you have found the end of the light penetration
    depth (pretty simple eh?)
  • The depth limit for angiosperms in freshwater is
    17m. Submersed aquatic vegetation tend to have
    limits that exceed the higher Secchi depths.
  • In the Chesapeake Bay the Secchi depths are
    usually 1-2m.
  • This makes the submersed aquatic vegetation
    limited to shallow water depths (less than 3m)

More life More death
  • Phytoplankton is growing abundantly and these
    microscopic floating cells are responsible for
    the increasing murkiness of the bays water
  • Phytoplankton are natural components of the
    Chesapeake Bay, yet they are growing faster than
    they can be consumed by other organisms in the
    food chain (oysters).
  • They cloud the waters and whats worse is when
    they settle to the depths of the bay where they
    lie from lack of light.
  • When they die they are food for bacteria and
    these bacteria consume virtually all of the
    oxygen dissolved in the water.
  • This results in anoxia, or oxygen depleted
    watersdead zones
  • without oxygen bottom-dwelling organisms cannot
    survive and other organisms are displaced from
    this habitat

The Dead Zone
  • Hundreds of square miles of anoxic bottom waters.
  • Amount of anoxic waters has tripled over last 40
  • Anoxic conditions can last in the bay for up to
    10 months
  • Recent studies have shown that wind currents push
    anoxic waters into tributaries and kill off crabs
    and fish that are unable to escape.

What can be done?
  • Upgrade sewage treatment plants and septic
  • Conserve energy to reduce amount of nitrogen
    released into the atmosphere.
  • Replace and maintain natural filters.
  • Low density housing in buffer areas.

What needs to be done?
  • In order to increase submersed aquatic vegetation
  • tests on nutrient loading and nutrient reduction
    may need to be bay wide
  • increased water clarity
  • the re-establishment of plant communities
  • transplanting

How do you control Phytoplankton?
  • Most evidence is showing that Nitrogen is the
    major cause of excessive Phytoplankton in some of
    the tributaries of the Chesapeake Bay.
  • This means a phosphorus control strategy would be
    inadequate to decline phytoplankton amounts but
    is still a necessary task
  • Reducing nitrogen inputs to the bay is the most
    important goal

  • Nutrient Management Plans
  • Control Pollution from manure
  • Install and maintain buffer strips in fields
  • At least 25,000 acres of Riparian buffer zones in
    watershed area.

Possible Regulations
  • Water Treatment facilities should release no more
    than 3mg/L of nitrogen.
  • Water Treatment facilities should reduce
    contribution by 42 million pounds annually.
  • Only 70 plants have been upgraded to 8mg/L
  • Future upgrades are at an approximate cost of 4.4
    billion over 10 years.

What is being done to help?
  • An innovative biological process is now being
    tested in Virginia on the York River to find a
    cost-effective and reliable alternative to the
    chemical addition process
  • A recently established Critical Area Protection
    Program is taking place in Maryland and
  • Maryland has adopted strict standards for
    development in a 1,000ft strip of land on the
    shoreline of the tidal Chesapeake Bay and its
  • Pennsylvania has taken the same strict controls
    on land around the Susquehanna River aimed in
    restoring the Chesapeake
  • These steps are currently being taken to evaluate
    and cause stricter controls on land use and its
    effect on nutrient loading that causes
    phytoplankton growth

High Tech Tools
  • Computer Simulations can determine where
    pollution is coming from
  • Computers simulate how air moves and how nitrogen
    interacts with other airborne compounds
  • Models suggest that 25 of nitrogen is being
    carried through the air from over 500 miles away.
  • Helps to determine point sources that need to be

  • Cooper, Sheeri R. Chesapeake Bay Watershed
    Historical Land Use Impact on Water Quality and
    Diatom Communities. Ecological Applications 5
    (1995) p703.
  • Chesapeake Bay Foundation. Save The Bay 22 Sept.
    2003 http//
    sotb_2001 _index.
  • Simon, C. Oxygen Changes in the Chesapeake.
    Science News Jan. 1984 p6.
  • Nemecek, Sasha. Virtual Pollution. Scientific
    American Jan. 1996 p24.
  • Weisburd, S. Climate conspires against oxygen
    and oysters. Science News Mar. 1986 p204.

  • D'Elia, Christopher F.. Nutrient Enrichment of
    the Chesapeake Bay, Enviornment. Mar 87. Vol 29
    Issue 2. P 6-11 and 30 -33Dennison, William C.
    Robert J. Orth, Kenneth A. Moore, J. Court
    Stevenson. Virginia Carter, Stan Koller, Peter
    W.Bergstrom and Robert A. Batiuk.
    Assessing Water Quality with Submersed Aquatic
    Vegetation. Bio Science. Feb 1993 Vol 43 p 86(9)
  • The Washington Post (no author). Spring Showers
    Bring Pollution. Enviornment. Sept 2003 Vol 45
    number 7 p 4-5Fayer, Ronald, Earl J. Lewis,
    James M. Trout, Thaddeus K. Garczyk, Mark
    C. Jenkins, James Higgins, Lihua Xiao and Altak
    A. Lal. "Cryptosporidium Paurvem in Oysters from
    Commerical Harvesting Sites in the Chesapeake
    Bay. Emmerging Infectious Diseases. Sept - Oct
    1999. Vol 5 Issue 5 p 706(5)
  • Sun, Marjorie. Acid Rain Said to Treaten Bay.
    Science. April 29, 1988. vol 240 n 4852 pg