Transcript PowerPoint Presentation - Chesapeake Bay

Chesapeake Bay Water
Pollution
Rob Douglas
John Misamore
Geography of the
Chesapeake Bay
“The largest and most
complex estuary in the
continental United
States”
It’s drainage basin
encompasses 64,000
square miles
It’s 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
Ocean.
Chesapeake Bay-The
Problem
The bay operates at about
one quarter of it’s potential
due to water pollution.
The bay has lost about 98%
of it’s oysters, 90% of it’s
grasses and 50 of it’s
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 Smith’s records
of the bay during the 1600’s.
A score of 100 describes what John Smith
recorded.
His records indicate that during the 1600’s
reefs were a threat to navigation.
The bay is believed to have been operating at
it’s full potential during the time John Smith
explored.
So how bad is it?
In the 2003 State of
The Bay report the
bay scored a 26 out
100.
Water quality was
at it’s 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.
Example:On the eastern
shore chickens outnumber
people 1000:1
Acid Rain Affecting the
Bay
FACTS:


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 utilities
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 Chesapeake’s estuary make-up also promotes
phytoplankton growth because the freshwater
circulation brings nutrients and affects the bay’s
Climate Changes
High levels of flow from tributaries creates
stratification in the bay.
Dense ocean water sinks to the bottom and
becomes anoxic.
Climate winds can push anoxic waters into
the tributaries.
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 more
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 amounts
 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 accelerated
 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
Tributaries
The Choptank River



the largest tributary on the eastern shore of the Chesapeake Bay
approximately 15,000 ha was vegetated with Ruppia maritima
around 1% of the Choptank River is less than 2m deep
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 70’s
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 vegetation
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 fecescontaminated estuarine waters.
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 72°C to render it noninfectious, or
freeze at -20 °C . Cooking is recommended over freezing.
The Chesapeake Bay
and Submersed Aquatic
Vegetation
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
waterfowl.
What does it do?
Provides food for waterfowl and critical habitat for shellfish
and finfish. It also affects nutrient cycling, sediment stability
and water turbidity.
What’s wrong with the
Aquatic Vegetation?
There has been a decline in
submersed aquatic
vegetation since the 1960’s 70’s.
This decline was related to
increasing amounts of
nutrients and sediments from
development of the bay’s
shoreline and watershed
There are approximately
25,000 ha of submersed
aquatic vegetation in the
Chesapeake which is only
10% of the historical
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 penetration.
 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
bay’s 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 what’s 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 waters;“dead
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 years.
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 systems.
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 amounts:
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
Agriculture
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
efficiency.
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 Pennsylvania.
 Maryland has adopted strict standards for development in a
1,000ft strip of land on the shoreline of the tidal Chesapeake
Bay and its tributaries
 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 regulated.
Sources:
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://www.cbf.org/site/PageServer?pagename=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.
Sources
D'Elia, Christopher F.. Nutrient Enrichment of the Chesapeake Bay, Enviornment.
Mar 87. Vol 29 Issue 2. P 6-11 and 30 -33
Dennison, 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 4-5
Fayer, 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 601(1)