Estuaries are bodies of water where freshwater rivers meet saltwater oceans, forming brackish water. They support rich ecosystems but are threatened by pollution and climate change. The Chesapeake Bay estuary is suffering from agricultural and industrial runoff, which is lowering oxygen levels and harming fish and crab populations. Rising sea levels and warmer water temperatures due to global warming are eroding wetlands and stressing native species in estuaries like Delaware Bay. Protecting these vital ecosystems is important for wildlife and coastal communities.

1. Estuaries
Essence Perry

2. Estuary
● An estuary or wetland is a partially closed body
of water in places where freshwater meets salty
ocean water.
● The roots of plants have to be submerged under
water for part of the year.
● The mixed water is brackish and depending on
the flow of freshwater, different types of
estuaries are formed.
● Usually form in river mouths, bays, inlets, gulfs,
and sounds are classified as estuaries.
Klamath River Estuary in OR/CA/WA

3. Types of Estuaries
● Coastal Plain: The most common type of estuary, they are formed when the rising sea
level after the ice age drowned the low lands or river valleys. Ex. Chesapeake Bay in MD of
Columbia River Estuary in Washington.
● Bar-built: The accumulation of sediment forms sand bars or barrier islands. Lagoons that
separate barrier islands from the mainland are bar built. Ex. Pamlico Sound in NC or
Laguna Madre in TX.
● Tectonic: Faulting or folding of rocks creates a restricted area that a river flows into. Ex.
San Francisco Bay formed by San Andreas Fault.
● Fjord (fee-yord): Melting glaciers raise the sea level cutting deep U-shaped valleys on
coasts. Ex. On the coasts of New Zealand, Alaska, Chile, Norway, and Canada.

4. Coastal Plain Estuary
The picture to the left
is Coos Estuary on the
West Coast and the
image to the right
Chesapeake Bay in
Maryland.

5. Function of Estuaries
● Estuaries filter out pollutants and chemicals in
water as it passes through.
● Estuaries can host thousands of species, they
are one of the richest and ecosystems in the
world.
● Migrating birds reproduce, migrate, and feed
in estuaries.
● Estuaries hold water and minimize the impact
of floods.
● Estuaries provide relief to droughts, they often
refill aquifers.
Estuary Map

6. Climate of Estuaries
● The climate of estuaries is varied because their
locations are very different, and every coast
has a different temperature.
○ The average temperature for an estuary is 55℉-
63℉, these temperature are most suitable for
organisms.
○ The average precipitation is about 6.67 inches.
● Some estuaries have four seasons and some
have 2 seasons depending on their location.
○ Part of the year estuaries are under water and the
other part they are emerged in water.

7. Common Estuarine Flora and Fauna Adaptations
● Organisms in estuaries use a lot of energy to resist changes in:
○ Salinity and in temperature, making them euryhaline organisms.
○ Strong currents and storm waves.
○ Varying exposure to sunlight.
○ Low oxygen levels in muddy soil and during low tide.
● The most common adaptation to overcome being
submerged underwater are:
○ Aerenchyma (air holes)
○ Floating leaves
○ Complex root systems
○ Thick and wide. leaves.

8. Examples of Adaptations for Estuarine Flora and Fauna
● Oysters and other bivalves, like mussels and clams,
are extremely adapted for high and low tides.
○ During low tides there is low salinity and oysters close up
their shells and stop feeding. They complete aerobic
respiration through their gills during high tide and anaerobic
respiration during low tides.
● Smooth cordgrass (Spartina alterniflora) is found in
salt marshes, they have special filters on its roots to
remove salts from the water it absorbs. They also
expel excess salt through its leaves. Oysters feeding

9. Seagrass Spike Grass Great Egret Starry Flounder
Sunflower Seastar Skeleton Shrimp Shriner Perch Bald Eagle

10. Apex
Predator
Bullshark Osprey Shore Bird
Tertiary
Consumer
Horseshoe crab Red Drum Catfish
Secondary
Consumer
Worms Fiddler Crabs Red Drum
Primary
Consumer
Oysters Worms Shrimp
Producers Phytoplankton Marsh grass Algae
Typical Organisms in the Food Web (3 Food Chains)
An example of
mutualism in
estuarine ecosystems
are sea slugs and
fish. The slugs
receive nutrients
from the dirt and
debris on the fish,
and in return the fish
is cleaned.

11. Causes of Environmental Disaster in Chesapeake Bay
● Agricultural runoff and wastewater from
treatment plants has entered the water causing
toxic algal blooms of cyanobacteria.
● The land development has caused sediment
and nutrients to enter the water, clouding the
water.
● The chicken farms are inadequately spreading
manure on the land, causing it to leach into the
water.
● The coal-fire plant raised their smokestacks,
sending the emissions towards the estuary.

12. Effects of a Polluted Chesapeake Bay
● Water quality is so poor there is low dissolved oxygen, indicating there are anoxic
conditions part of the year.
● 50% of the striped bass and blue crab population is suffering from an infection
caused by mycobacteria, which attacks the internal organs of the fish.
● Most of the vegetation has disappeared because it couldn’t adapt to the abundance of
sediment on the estuary bottom.
● There are dangerous algal blooms of cyanobacteria:
○ This bacteria can cause death in animals and small children.
○ These blooms dissolved oxygen and block sunlight, which prevents underwater grasses from growing.
○ The zooplankton population is declining because the phytoplankton population is. Most predators of
zooplankton are declining, causing apex predator populations to decline.

13. Effects of Global Warming on Estuaries
● The increasing temperatures of the oceans has made it
difficult for native species to survive. Also parasites
and invasive species thrive in warmer temperatures
● The increase CO2 has dissolved in water, making it
more acidic and native species are rapidly dying off,
and eroding faster, making the water clouded.
● The increase in sea levels has eroded estuaries or it is
sinking the land.
● Floods, droughts and other extreme weather events
will alter water flows, leading to more polluted runoff
and lower water quality.

14. “Domino Effect” Article- Yale 360
● Delaware Bay is similar to the Mississippi delta, muddy
and wet, it provides a clear picture of the impact of global
warming.
● The area has faced storms, increasing sea levels, and
eroding wetlands.
● Trees, marsh grasses, fish, oysters, mussels, crustaceans,
shorebirds, marsh birds, and waterfowl are being
affected.
● Sea levels are now rising at a rate of roughly .14 inches
per year. Kreeger says that by 2100, when that rate is
expected to double or triple, Delaware Bay could lose 90
percent of its wetlands to rising seas, ruining the
complex ecosystem.

15. Works Cited
Williams, Ted . "Domino Effect: The Myriad Impacts of Warming on an East Coast
Estuary." Yale E360. Yale Environment 360, 17 May 2017. Web. 19 May 2017.
Bulletin, Bill Reid For The. "Exploring The Last Green Valley: Long Island Sound an
important estuary." The Bulletin. The Bulletin, 19 May 2017. Web. 20 May 2017.
Bill Monroe | For The Oregonian/OregonLive. "States may consider estuary sturgeon
retention seasons next week." OregonLive.com. OregonLive.com, 19 May 2017. Web. 21
May 2017.