Download Salt Marsh Ecology

Salt Marsh Ecology
HOBCAW BARONY
THE BELLE W. BARUCH FOUNDATION
Lesson Description
Students begin this adventure in the Hobcaw Barony Discovery Center. Using the salt marsh exhibit,
1200 gallon fish tank and shell midden, students listen to the instructor talk about plants, animals, tides,
and other facts about the marsh. Many questions regarding the lesson are asked and the answers are
clues to the riddles the students will be solving. At the salt marsh trail, students will work in groups
answering six riddles pertaining to plants and animals in the salt marsh. Each will draw and describe the
plant/animal and discover its adaptations based on the riddle.
SC State Standards covered
Standards
Standard 4-2: The student will demonstrate an understanding of the characteristics and patterns
of behavior that allow organisms to survive in their own distinct environments. (Life Science)
Indicators
4-2.2 Explain how the characteristics of distinct environments (including swamps, rivers and
streams, tropical rain forests, deserts, and the polar regions) influence the variety of organisms
in each.
4-2.3 Explain how humans and other animals use their senses and sensory organs to detect signals
from the environment and how their behaviors are influenced by these signals.
4-2.4 Distinguish between the characteristics of an organism that are inherited and those that
are acquired over time.
4-2.5 Explain how an organism’s patterns of behavior are related to its environment (including the
kinds and the number of other organisms present, the availability of food and other resources,
and the physical characteristics of the environment).
4-2.6 Explain how organisms cause changes in their environment.
Salt Marsh Ecology
HOBCAW BARONY
THE BELLE W. BARUCH FOUNDATION
Focus Questions
1.
2.
3.
4.
What is an estuary?
What are three plants that live in the salt marsh?
What are three animals that live in the salt marsh?
What special adaptations do the plants and animals you listed above exhibit that enable them to
live in the salt marsh?
5. What is detritus and its role in the estuarine ecosystem?
Teachers need to provide:




Pencils (one per student)
Clipboards (one per student)
2-page Blank Riddle Sheet (attached)
o (one copy per student per page)
o Look for the
“Circle Zone” sheet
o (one copy per student)
o Look for the
Instructor will provide:



Plant/Animal cards
Riddles written by Richard Camlin
Laminated field guide for leaders
Lesson Plan
Part One: The Saltwater Aquarium
Students will be seated in front of the 1200-gallon saltwater aquarium inside the Hobcaw Barony
Discovery Center for a discussion on the different species of plants and animals found in the salt marsh
ecosystem. With each species, specific adaptations they have in order to live in the salt marsh and how
each plant or animal reacts to different things in the marsh will be introduced by the instructor.
Part Two: Salt Marsh Trail
After traveling to the salt marsh trail, students will be immersed into the salt marsh ecosystem as they
read riddles describing the adaptations previously discussed and see examples of the plant and animal
species in their natural habitat. The instructor and other guides will lead groups of students to
different locations where they will see a variety of salt marsh species including fiddler crabs, cordgrass,
periwinkle snails, bearded mussels and more!
Part Three: Circle Zones
This part of the lesson still takes place at the salt marsh trail and focuses more on the variety of
species found in each of the four zones of the marsh. With the students being more familiar with the
salt marsh species after completing the riddles, they will go on to drawing what they see inside a hoola
hoop placed on the ground in each of the four zones of the marsh.
Salt Marsh Ecology
HOBCAW BARONY
THE BELLE W. BARUCH FOUNDATION
Teacher Preparation:
An estuary is the thin zone along a coastline where freshwater systems and rivers meet, mix with a salty ocean,
and become brackish. An estuary begins where fresh river water flows into coastal bays and inlets. These areas of
transition between the land and the sea are driven by tides, like the sea, but sheltered from the full force of
ocean wind and waves, like a river. When fresh water meets salty seawater, both liquids combine turning into a
brackish mixture.
Estuaries are unique places that are valuable to the environment and to society.
characteristics, they all play vital roles in the environment and in our lives.
Each having its own specific
Estuaries change constantly, and this change is necessary for an estuary’s health. Estuarine organisms have
adapted to tolerate the changing conditions of estuaries. Tides, depth and location, weather patterns, seasonal
cycles, and climate change all lend to the ever changing characteristics of an estuary. Tides are necessary for
healthy estuaries as they flush the systems and provide nutrients to keep the food webs functional. However,
tides create constantly changing conditions of exposure to air and inundation to water. The depth and location of
an estuary affects and changes conditions such as temperature and number of organisms present. The Earth’s
climate is warming at a faster rate than normal. This warming is causing sea level to rise, which may ultimately
result in flooded and lost estuaries.
A common estuarine habitat found here in South Carolina is coastal marshes. Coastal marshes along the oceans are
called salt marshes, or tidal marshes. Salt marshes prefer cool, temperate climates (winter temperatures near or
below 10o C). They occur in areas that are directly affected by tidal waters.
Many different types of plants such as marsh grasses, rushes and sedges grow in salt marshes. These different
types of plants require different water levels, oxygen content and salinity which determine where they grow in the
lower, middle or upper marsh. Salt marsh plants are highly tolerant of the salty waters. They absorb the estuary
waters through their roots, and special plant cells concentrate the salt ions, freeing up freshwater to be used by
the plant.
Salt marshes can filter small amounts of pollutants and runoff while the marsh grass filters and traps silt.
However, too much nutrient or sediment input will create an unbalanced situation causing the health of the marsh
to decline.
Salt marshes provide important protection and nursery areas for fish, shellfish and crustaceans. Small fish and
other animals live in the shallow waters and dense grasses and hide here from predators. Salt marshes also trap
decaying organic matter (detritus) that is used as food by some estuarine animals. Salt marshes provide food,
fresh water and shelter for migrating birds on their long journey between nesting and wintering habitats.
Salt marsh plants have strong root systems that help them withstand surges of water that come from storms.
Many winding creeks and channels snake through salt marshes. They carry detritus and deposit sediment, replacing
what storms, floods and tides flush out. Salt marshes develop in low energy waters, meaning that there is usually
only a small amount of wave action in the area. Decaying plants, fish and animals are broken down by bacteria and
fungi helping produce the ripe, rotten egg smell common in salt marsh mudflats.
*Excerpted from estuaries.noaa.gov
Salt Marsh Ecology
HOBCAW BARONY
THE BELLE W. BARUCH FOUNDATION
SALT MARSH ECOLOGY VOCABULARY LIST
Adaptation (adapt): a genetically-based body feature or behavior that allows an organism to be better
suited to its environment.
Anaerobic: without air, no oxygen.
Benthic: relating to the ocean bottom.
Brackish: slightly salty water with salinity between 0.5 ppt and 32 ppt. (ppt = parts per thousand)
Conservation: careful preservation and protection of ecological processes and biodiversity of the
environment
Detritus: newly dead or decaying organic matter coated with bacteria.
Estuary: a semi-enclosed body of water which has a free connection to the open sea and within which
seawater is measurably diluted by fresh water derived from land drainage. Some unique Great Lakes
coastal wetlands are referred to as freshwater estuaries. They occur where rivers and Great Lakes
water mix in shallow wetlands located near the mouth of a river.
High marsh: the area of the marsh flooded infrequently by the high tides associated with new and full
moon.
Intertidal: estuary habitat flooded by high tide waters only.
Invasive species: non-native species of plants or animals that out-compete native species in a specific
habitat.
Low marsh: the area of marsh flooded twice daily by tides and dominated by Spartina alterniflora.
Pelagic: of or in the open ocean or open water; in the water column.
Salinity: the concentration of salts dissolved in salt water.
Tides: periodic rise and fall of ocean waters due to gravitational pull of sun and moon, and rotation of
earth.
Wrack line: a string of debris stranded by last high tide; cast ashore seaweeds, isolated sources of
food and shade support an important community of isopods and amphipods as well as providing food for
birds.
Salt Marsh Ecology
HOBCAW BARONY
THE BELLE W. BARUCH FOUNDATION
Background:
Salt Marsh Values
Salt marshes in the United States occur along the Atlantic Coast from New Jersey to Northern Florida and along
the Gulf of Mexico. These coastal estuaries are considered some of the most fertile ecosystems in the world.
South Carolina alone contains over 400,000 acres of protected salt marsh. These marshes help to protect the
mainland during storms, filter pollutants entering wetlands and oceans, and act as a nursery for numerous species
of fish, shrimp, crabs. Salt marshes are also an area full of commercial and recreational opportunities.
Cultural
While salt marshes were long considered of no value, strictly in terms of agricultural dollars, they have been part
of the lifeblood of many living along the coast for centuries. Native Americans harvested oysters and clams,
throwing them into “trash” piles that we now call shell middens. Colonists fished the same areas and rice planters
spent summers at the salt marsh because of the lack of mosquitoes that carried malaria. Due to unique networks of
tide-controlled fresh water rivers and rich, loamy, marshy areas, the planting of rice here was ideal. Winyah Bay, the
third largest estuary on the east coast, was also the location of the historic commercial fishing of sturgeon for
caviar, and our estuaries still offer a cultural connection to our coastal communities of today with a variety of
recreational activities.
Ecological
Salt marshes are extremely fertile; there are over 900 of species of fish and invertebrates living in tidal creeks,
estuaries and nearshore areas in South Carolina. Our coast’s twice daily tides (2 high and 2 low) are necessary for
healthy estuaries as they flush the systems and provide nutrients to keep the food webs functional. The cycling of two
nutrients, nitrogen and phosphorus, is especially important in estuaries. In the water cycle, estuaries serve as places
where evaporation of water occurs, and also serve to recharge ground water.
Economic
Healthy estuaries and salt marshes are critical to ocean dependent industries such as tourism and commercial
fisheries. In a 2009 economic report for Horry and Georgetown Counties in South Carolina, tourism accounted for
over 98% of almost 25,000 ocean dependent jobs. According to the South Carolina Department of Natural
Resources, commercially important species of shrimp, oysters, clams and blue crabs were valued at $14.81 million in
2011. Recreational fisheries also provide millions of dollars to the state’s economy each year.
Response to Climate Change
Research conducted at Hobcaw Barony has shown that there are effects of climate change in our area. According
to current research by Dr. Dennis Allen with the Belle W. Baruch Institute for Marine and Coastal Sciences, since
the 1980’s the winter water temperature has increased by 2 degrees Celsius. Long term monitoring of North Inlet
estuary indicates that sea level is rising in our area at an average rate of 3 millimeters per year and the projection
is that this rise will escalate. For North Inlet, this means that areas of the salt marsh could drown and convert to
less productive open waters.