Transcript Marine Grasses

Marine
Grasses
By: Megan Schmelzle, Mitch Woods, and Kelly Cohen
Marine Grasses
• It is in the plant kingdom.
• Marine grasses typically grow along the shores
of protected bays and inlets along the coasts of
the Atlantic Ocean, the Pacific Ocean, and the
Gulf of Mexico.
• There are two predominant types of marine
grasses;
» Marsh Grasses
» Sea Grasses
Marine
Grasses
Marsh
Grasses
Reed grass
Cordgrass
(spartina)
Phragmites
Spartina
alterniflora
Sea
Grasses
Glasswort
Spartina
patens
Eel Grass
Turtle
Grass
Marsh Grasses
• Marsh grasses grow in calm bays and along sandy
beaches.
• Marsh creeks, sounds, and inlets are all part of
estuaries, where seawater meets and mixes with fresh
water from the coastal rivers and runoff from the
surrounding uplands.
• There are two common types: reed grass and cordgrass.
Reed grass
Cord grass
Environmental Impact
• Short life cycle  much of the salt marsh contains dead
and decaying marsh grasses.
 The products formed from the decay enrich the water with
important nutrients.
 Plankton feed on these nutrients.
• These plankton are a major food source for other
organisms and therefore marshes are the most
biologically productive ecosystems in the world.
Reed Grass
• One abundant type of reed grass is
called Phragmites australis, (the
common reed).
• It is a large perennial found in wetlands
throughout temperate and tropical
regions of the world.
– (perennials are plant that grows through all
seasons rather than dying in the winter and
regenerating.)
• They are easily identified by their fluffy
brown tassels.
• They grow in extensive stands (known
as reed beds) and usually in damp
ground at the upper edges of estuaries
and in other wetlands.
Cordgrass
•
Cordgrass is a type of marine grass found along the water’s
edge in the intertidal zone.
•
Grows in the lower intertidal zone which means that it is
covered by water during periods of high tides and it can tolerate
changes in salinity and temperature.
•
Species of cordgrass have adaptations that enable them to
survive in water that is salty
•
Special glands are able to excrete salt through the leaves.
Salt crystals can be seen and tasted on the surface of cordgrass
leaves.
Spartina Alterniflora
 Also known as Smooth Cordgrass or Salt
marsh Cordgrass.
It is native to the Atlantic coast of the
Americas from Newfoundland, Canada
south to northern Argentina, where it forms
a dominant part of brackish coastal salt
marshes.
 Fiddler crabs and mussels live on and
around its roots.
 It can transport oxygen from its leaves
through the stems to the roots through a
system of air spaces called aerenchyma.
Besides providing a supply of oxygen to
the roots, it also oxygenates the soil
immediately surrounding the plant.
 The oxygen allows bacteria to live in the
soil near the plant's roots, and the bacteria
supply nutrients (nitrates, phosphates,
sulfates, potassium…) to the cordgrass.
•[This is called a symbiotic relationship]
Environmental Impact
• Invasiveness
– Spartina alterniflora can become an invasive plant,
either by itself or by hybridizing with native species
and preventing continuation of the pure native strain.
– However, Common reed can also become invasive
and is harmful to the Spartina alterniflora. This is
detrimental to the environment because it is not as
productive or beneficial to a salt marsh as cordgrass.
• It also has the ability to break down industrial
pollutants that flow into the marshes, releasing
the chemicals as a harmless gas.
Spartina Patens
• It is a shorter, more slender species of
cordgrass
• It is found in the upper intertidal zone
– It gets flooded only during
periods of very high tides.
• It produces flowers and seeds. The
flowers are a deep purple from June to
October and turn brown in the winter
months.
• It is also less tolerant of saltwater than
some other marsh grasses.
Glasswort
• It is another type of marsh grass that is salt-tolerant and
grows in the upper intertidal zone of beaches from
Massachusetts to the Gulf Coast.
• The short, thick waxy stems store the fresh water that the
plant needs to survive.
• They have a high salt content in their cytoplasm, which
dispels the need to eliminate salt
• A common variety of the glasswort is Salicornia.
Dune Grasses
• Dune grasses are
planted to retain or
increase sand volume.
• These plants stabilize
the sand that already
exists by reducing the
ability of wind to move it
elsewhere
• In addition, the plants
will – over time - cause
more sand to be
deposited.
Sea Grasses
• They grow in the shallow subtidal zones along shore.
• Sea grass beds are highly diverse and productive
ecosystems. They can harbor hundreds of animals.
• There are four commonly recognized species:
» Eel grass
» Turtle grass
» Shoalgrass
» Widgeongrass
Sea Grass Ecology
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The sheltering canopy of sea grass creates a calm, stable and protected habitat
for a wide assortment of marine life. Grass beds are especially important as
nursery areas for young life stages of marine fish, shrimp and crabs.
Healthy green sea grasses provides numerous grazers, such as manatees, sea
urchins, and green sea turtles with their main source of food. Most of the sea
grass, however, becomes part of the food chain as decaying matter. Microbes,
shrimp, many fish and invertebrates feast upon the decaying sea grass. Predators
visit grass flats in their search for food.
Sea grasses help other organisms by recycling nutrients, improving water clarity
and cleaning marine waters of pollutants, aiding the growth of other marine life, &
stabilizing sediments
They have leaves, stems and flowers, as well as roots. In healthy sea grass beds,
when leaves are lost to storms, grazing, or other natural disturbances, they grow
back quickly, But when sea grass roots are damaged, often by motorboat
propellers, they may not grow back for years, if ever...
Sea Grass Ecology 2
• They are called this because their leaves are long and
narrow and are very often green. They often grow in large
"meadows” which look like grassland.
• They are photosynthetic, thus limited to growing in the
photic zone. They mostly occur in shallow and secluded
coastal waters anchored in sand or mud bottoms. They
pollinate and complete their entire life cycle underwater.
• Sea grass is crucial to the food-chain: dugongs, manatees,
fish, geese, swans, sea urchins and crabs feed on it.
Sea grass distribution shown in red
Sea Grass Reproduction
• Sea grasses produce flowers (small structures located at
the base of the plant.)
• Pollen from the flowers is dispersed in long threads in
the water.
• When the egg cells are fertilized by pollen, seeds are
produced and shed into the water
• If they settle on a suitable
substrate, the seeds will germinate.
Eel Grass
• Grows in protected bays and inlets of the subtidal zone.
• The individual plants grow close together forming beds that
provide shelter for mollusks, arthropods, and fish.
• Eelgrass is widely distributed in temperate and subtropical
regions. Found along Atlantic coast from Maine to Florida
and Pacific coast from Washington to California.
Zostera Marina
• A.k.a common eelgrass
• Grows mainly on sand or fine
gravel in the subtidal zone.
They are found in sheltered
shallow inlets, bays, estuaries
and lagoons.
• Grass like flowering plant with
dark green, long, narrow,
ribbon shaped leaves 20-50
cm in length with rounded tips
Zostera Continued
• Zostera beds are important for:
–
–
–
–
sediment deposition
substrate stabilization
as substrate for epiphytic algae and micro-invertebrates
as nursery grounds for many species of economically important
fish and shellfish.
• Zostera often beds in bay mud in an estuarine
setting.
• It is an important food source for several species
of birds as well as marine animals.
Turtle Grass
• Large beds grow in the bays and inlets of warmer waters, along the
coasts of Florida and the Gulf of Mexico
• Has underground stems
Called rhizomes
– They form an interlocking
mat that helps to stabilize the
sandy seafloor.
• They are also home to a variety of sea animals
• It is an important source of food for sea turtles
•
Turtle grass is often washed ashore in such quantities following storms at
sea that it is collected and used as a fertilizer.
Shoalgrass
Halodule wrightii
•Shoalgrass ranges from North Carolina, south along the
Atlantic and Gulf of Mexico coasts, to the Caribbean. It is also
found off of portions of South America, northwestern Africa,
Indian Ocean, and the west coast of Mexico.
•It is a colonizer of disturbed area where turtle grass and
manatee grass cannot grow. It is often found in waters too
shallow or too deep for other sea grasses to grow. Of all the
sea grasses shoal grass can withstand the widest range of
temperatures and salinities.
•Ecologically the important thing about Shoal Grass is that its
roots penetrate an average of four inches into the substrate,
thus stabilize offshore sand.
Widgeongrass
Ruppia maritima
• Widgeon grass is a completely submerged perennial
plant with single or multi-branched stems up to 3 feet
long. Leaves are alternate, simple, and thread-like up to
4 inches long with sheaths. Flowers and fruits in clusters
at the end of individual stalks. Widgeon grass can live in
fresh or brackish water.
• Widgeon grass is a very important wildlife plant with the
stems and leaves being heavily utilized by many duck
species, especially after its death and decomposition. In
addition, many animals call this grass home:
amphibians, reptiles, etc.
In Conclusion…
These amazing and unusual marine plants
are clearly crucial to the environment of
the true “Final Frontier.” Without any type
of marine grass, it is evident that not only
would the oceans cease to function, but so
would life outside the water. It is important
to keep our oceans healthy, as we
continue to not only learn, but grow as a
world.
Sources
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http://www.kingston.ac.uk/international/guidance-and-advice/your-home-country/overseasrepresentatives/
http://www.birdwatchersdigest.com/blog/archive/2007_11_01_archive.html
http://commons.wikimedia.org/wiki/File:Spartina_alterniflora.jpg
http://oceanworld.tamu.edu/students/fisheries/fisheries2.htm
http://aquat1.ifas.ufl.edu/node/482
http://www.dcr.virginia.gov/natural_heritage/ncEId.shtml
http://www.armofthesea.info/flora_fauna/ff_kingdomspp/plantae.htm
http://www.mesa.edu.au/friends/seashores/ewtz.html
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http://www.worldatlas.com/aatlas/infopage/gulfofmexico.htm
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http://www4.ncsu.edu/~dbeggles/education/synergy/bluecrab/bssgrass.html
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