Describing the physical aspects of the Bay

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Getting Acquainted with the Chesapeake Bay

• Describing the physical aspects of the Bay
• Natural History
• Estuary
• The Bays Watershed

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Criteria that define Estuaries

• Semi- enclosed coastal area
• Free access to open ocean
• Fresh water derived from land drainage
  (measurably diluted)

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Chesapeake Bay Watershed
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Natural History of the Chesapeake Bay
11,000 ybp

• Formation of the Bay began 17,000 ybp with the
  end of the Pleistocene Ice Age

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Tributaries of the Chesapeake

• The Rivers of the Western Shore perform a very
  different function than those of the Eastern Shore

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Chesapeake Bay as an Ecosystem

• Biotic components all living organisms
• Interactions among organisms
• Abiotic components non-living, chemical and
  physical factors
• Temperature, light, nutrients, water

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Habitats of the Bay

• Habitat is any part of the environment where
  organisms live
• Forests
• Wetlands
• Islands
• Rivers and Streams
• Shallow water areas
• Open water
• Aquatic Reefs

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• All organisms have certain habitat requirements
  and display adaptations that suit them to live in
  those habitats
• Adaptation structural, physiological,
  biochemical, and behavioral characteristics or
  organisms that promote survival and reproduction
  under a particular set of environmental
  conditions.
• Adaptations originate during biological evolution
• Because organisms are adapted to their habitats
• Habitat loss jeopardizes species

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Biotic Components of the BayHome to some 2000
species

• Bacteria
• Cyanobacteria
• Marsh and soil bacteria
• Protists
• Phytoplankton
• Zooplankton
• Plants
• Aquatic vegetation
• Marsh plants
• Forest species

• Animals
• Invertebrates
• insects
• crabs, snails, clams
• Vertebrates
• Fish
• Amphibians
• Reptiles
• Mammals
• Birds
• Fungi

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How deep is the Bay?

• The Bay is characterized as a marine ecosystem

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• Diverse aquatic habitats are essential to species
  diversity
• Notice the species which occupy each habitat

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Food Web of the Chesapeake
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Primary Producers The Plankton Soup

• Phytoplankton
• Habitat Open and Shallow waters
• Primary Producers in the Estuary
• Cyanobacteria
• Diatoms
• Green algae
• Brown algae
• Dinoflagellates
• SAVs

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Primary producers and Decomposers detritivores
Marsh Muck A rich community of bacteria, algae,
and protozoans
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• Zooplankton are primary consumers Single celled
  animals
• Invertebrates
• Copepods
• Jellyfish
• Comb jellies
• juvenile stages of blue crabs oysters

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Habitats Shallow Waters

• Provide resources and conditions for survival for
  many species
• Light, temperature, mud, proximity to wetlands
• Includes the benthos and its species

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Submerged Aquatic Vegetation

• Importance of SAVs
• Habitat for shrimp, blue carbs, juvenile fish
• Clarify the water by slowing down currents
• Root systems stabilize bottom sediment,
• Dissipate wave energy, preventing erosion
• Absorb nitrogen and phosphorus therefore reducing
  the chance of an algal bloom

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Aquatic Animals

• Invertebrates
• Insects
• Crabs
• Crustaceans
• Clams
• Snails
• Oysters

• Primary Consumers
• and Detritivores
• Many exist in the shallow water community

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Aquatic Secondary Consumers

• Nekton of the Pelagic Zone
• Anchovies
• Menhaden
• Herring
• Shad

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Aquatic Tertiary Consumers

• Occupy the pelagic zone
• Mergansers
• Striped Bass
• Bluefish
• Sturgeon

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Terrestrial Secondary ConsumersReptiles and
Amphibians

• 13 species of frogs/toads
• 8 species of Turtles
• 14 species of snakes
• Predators of insects and rodents
• Prey for Eagles, Osprey, Owls, Herons, and
  Racoons

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Terrestrial Secondary Consumers Reptiles

• Northern Diamond back terrapin
• Red-bellied turtle
• Eastern Mud turtle
• Eastern Painted turtle

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Birds Terrestrial Tertiary and Quaternary
Consumers

• Herons and Egrets
• Osprey (Sea Hawks)
• Bald Eagles
• http//www.friendsofblackwater.org/camcentral.html

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Tertiary and Quarternary Consumers Mammals

• Raccoons
• Muskrat
• Nutria
• Otters

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Energy flow in Ecosystems
Available Energy
Productivity
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How the abiotic components of the bay affect
organisms

• Circulation patterns
• Salinity
• Temperature
• Oxygen content
• Sediment load
• Nutrient load
• Toxic chemical load

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About Limiting Factors

• Abiotic Factors can limit the
• Distribution
• Abundance
• Growth of organisms
• Remember that organisms are adapted to their
  particular environment or habitat
• They have a range of tolerance for abiotic
  conditions
• Abiotic factors can limit the types of organisms
  that survive in a habitat

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1. Water Circulation

• Transports plankton
• Eggs
• Larvae
• Sediments
• Dissolved gases
• Minerals
• Nutrients

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• Water Circulation
• Water fluctuation changes seasonally
• Spring and summer
• Fresh water from the northern part of the Bay
  forms a layer over the colder, more dense salt
  water coming up from the southern part of the Bay
• No mixing
• Fall and Winter
• Less fresh water from the north
• Atmosphere cools the upper layer of water
• More mixing

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Water Circulation in the Bay

• Some fish use the zones where fresh water and
  salt water collide as a nursery
• Turbidity increases nutrient cycling
• Increases phytoplankton growth
• Great food for young fish

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2. Salinity (g/L) ppt Fresh 0-0.5 ppt
oligohaline 0.5-5 ppt mesohaline 5-18
ppt polyhaline 18-32 ppt Ocean gt32 ppt

• Salinity affects the behavior of Animals
• Fish spawn in fresh water
• White perch and striped bass
• Eels spawn in ocean water
• Plant communities

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Limiting Factors
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• 3. Temperature
• Temperature affected seasonally
• 0-32 º F
• Up to 84 º F
• Shallow or Deep waters
• Influences feeding
• Reproduction
• Movement of Organisms

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4. Oxygen Content

• Layering of water prevents mixing
• Anoxic conditions tend to occur in the summer
• In the lower water levels of the Bay (organisms
  use up all the O2)
• Crab jubilee
• Fish kills
• Phytoplankton Blooms (Algal blooms) occur in the
  upper water levels of the Bay

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Nutrient Loading

• Nitrogen and Phosphorus are often limiting
  factors for plant growth
• Addition of fertilizers
• Excessive inputs of nitrogen and phosphorus lead
  to nutrient overloading
• Agricultural fertilizers
• Sewage
• Live stock facilities
• Result in Algal blooms

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Algal Blooms

• Phytoplankton grow rapidly
• Oxygen depletion
• Water turns green, brown, or even red
• The red tide
• The cell from hell Pfiesteria piscicida
• Dinoflagellate that produces a toxin that
  paralyzes fish and causes open sores
• Affects people too

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• River flow strongly influences nutrient loading
  and oxygen content
• Climatic factors influence yearly and decadal
  variations

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Preventing Nutrient Loading

• In 1987 Pennsylvania, Maryland, and Virginia
  agreed to reduce nutrient loading by 40 by
  2000.
• Controlling run-off from agriculture
• Suburbs and urban areas
• Removing more nutrients from sewage and
  industrial facilities
• Banning phosphorus containing detergents
• Reducing fertilizer use
• Some changes happened, but nutrient loading was
  reduced by only 21
• A new agreement for reducing levels by the year
  2010

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The Bay as a Tragedy of the Commons

• Once supported a multi-million sports and
  commercial fish industry for striped bass
• 1980 MD and VA banned striped bass fishing
• Millions of pounds of herring once caught in the
  bay, 1970s catch was down 90
• Same fate for shad, yellow perch, white perch and
  other fish

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• Vast areas of shallow water habitats have
  disappeared. So have the SAVs. Down to 20 in
  1984
• Development, marinas, pollution
• Anoxic conditions in the summer are not uncommon
  in some parts of the Bay
• Dead Zones of the Chesapeake

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A Keystone Species of the Bay
Crossostrea virginicus

• Oysters filter impurities out of water
• Scientists calculate that in earlier days when
  they were more numerous, they could have filtered
  the whole Chesapeake Bay in six days.
• The same oyster can be male or female at
  different times in its life cycle.
• Americans eat more oysters than any other people
  in the world.

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Why is this happening to the Bay?

• Population doubled within 50 years
• 8 million in 300 years
• 16 million in the last 50 years
• High resource-consuming and high-waste producing
  lifestyle
• Chesapeake Bay Foundation (CBF) evaluates the Bay
  is operating at 27 of its capacity

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The State of the Bay 2007

• shows modest improvement, with the health index
  up two points to 28 this year
• Much of the improvement was driven by Mother
  Nature,
• with near record low spring rains.
• Even with the improvement, the health of the Bay
  gets an unacceptable D grade.

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The Good News

• Were at a stasis point, we have stopped the
  decline
• Striped Bass population is recovering. Limited
  fishing is now permitted
• SAVs are returning!
• Biology Dept. at the Essex campus
• Native species are returning

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Local and State Efforts to Restore the Bay

• Smart Growth sustainable development
• CBF pushing for a new Bay governance that would
  have the authority and means to set firm limits
  on pollution

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