EstuariesEstuaries

Maia P. McGuire, PhDMarine Extension

Agent

A partially enclosed body of water formed where fresh water from rivers and streams mixes

with salty water from the ocean.

What is an Estuary?

Why are estuaries important?

They are very productive ecosystems which provide

habitats for wildlife

• To find shelter• To find food

• As breeding grounds

Salt marsh

Mangroves

Oyster bars

Mud flats

Beach and open water

Horseshoe crab

Blue crab

Fiddler crab

White shrimp

Striped hermit crab

Jellyfish & comb jellies

Moon snail

Ribbed mussel

Crown conch

Marsh periwinkl

e

Spinner

Scalloped hammerhead

Bonnethead

Butterfly ray

Stingray

Estuaries provide:

• Water filtration• Flood control

• Recreational enjoyment

How do estuaries benefit humans?

• Water filtration

Water draining off the uplands through salt marsh has much of the sediment and nutrients filtered out. This filtration process creates cleaner and clearer water.

• Flood control:

Wetlands absorb flood waters and dissipate storm surges.

• Recreational enjoyment:People love estuaries for their beauty and for fishing, swimming, boating, diving, wildlife viewing, hunting, learning, and working.

• Accidental and deliberate actions

Human Impacts on Coastal Environments

• Ballast water • Release of aquarium

specimens• Deliberate introduction of

plants• Introduction of plants by birds

etc.

Introduced/exotic species

• Direct competition with local species– Native species may be displaced

• Habitat modification• Health impacts on wildlife and

humans

Problems with exotics

• Some red tide algae• Brazilian pepper• Walking catfish • Zebra mussel • Green mussels• Lionfish

Examples of introduced species

• Alteration of water flow patterns– Agricultural use– Residential/drinking water use– Flood control

• Filling of wetlands for construction and pest control (mosquito)

• As human population grows, so does stress on coastal areas

Habitat modification

• As percent increase from 1990-2000

– Nassau County— 31%– Duval County—16%– St. Johns County—47%– Flagler County—74%

– Florida average—24%

Local population growth

• Almost 60% of Florida’s freshwater marshlands have been destroyed since 1936 (mostly in the Kissimmee-Everglades region)

• About 30% of the remaining natural areas in Florida (upland and wetland) are protected

Wetland losses

• Filling for construction– Alters drainage patterns– Removes habitats– May isolate wetland areas – May introduce sediment into

coastal areas

Physical alteration of wetlands

• Misuse/overapplication of fertilizers

• Use of wetland areas as biofilters

• Acid rain• Runoff from

urban/agricultural areas– Pesticides– Petroleum

Chemical alteration of wetland areas

Point-source vs. non point-source pollution

• 51% of oil entering the oceans comes from runoff– 5% is from big spills– 19% is from routine maintenance– 2% is from offshore drilling– 13% is from burning fuels (e.g.

car exhaust)– 10% is from natural seeps

Oil pollution

• The typical American discards 5 lbs of garbage per day– 40% is paper– 17.5% is yard waste– 8.5% is metals– 8% is plastic– 7% is glass

Duval county = 311,000 lbs of plastic per day

Trash in the coastal environment

Fishing line/rope/nets

Balloons/plastic bags

Bottles/containers

Plastics

…what you can do to help protect the coastal environment

Is It All Hopeless?

• Pay attention to labels and what you put down the drain– Dispose of hazardous materials

properly– Call the county solid waste

department if you are unsure how to dispose of something safely

At home

• In the garden– Read and follow instructions on

fertilizers and pesticides; use natural methods as much as possible

– Use mulch to reduce the need to water

– Use native, drought-tolerant plants

– Use sprinklers conservatively

• When working on the car– Most fluids that come out of

the car are hazardous—take them to a recycling center (auto shop)

– Repair leaks promptly– Do not wash oil/gas/antifreeze

into the street—absorb spills using kitty litter or special oil absorbing pads

• Know the environment– Don’t run aground/avoid shallow water– Observe speed limits and no wake zones

• Fuel responsibly– Don’t overfill—spilled gas will go straight

into the estuary

– Don’t discharge bilge water into the estuary unless you have an oil-absorbing product in your bilge

When boating

• Dispose of wastes properly– Collect garbage on the boat and dispose of

it when you return to shore– Use pumpouts

•Clean your boat responsibly–Use small amounts of biodegradable soap or use natural cleaners–Don’t let paint chips get into the water

• Don’t leave monofilament fishing line in the environment– Cut it into small pieces and

put it in the garbage– Look for monofilament

recycling stations

When fishing

• When visiting coastal areas, pick up garbage that you see, especially plastics

• Participate in organized cleanup events/volunteer

• Try to avoid trampling vegetated areas (dunes, saltmarsh)

• Don’t feed wild birds/animals• Educate others

Do your part