The Salt Marsh
Created By:  Caroline Leggett
               Nancy Vest
                       Jennifer Williams


Goal:  Process of Science--To enable students to demonstrate the process of science by posing questions and investigating phenomena through language, methods and instruments of science.

Objectives:  1.  The students will compare and contrast the different components of the salt marsh.
                           Theme 1.3: The acquiring, recording, arranging and storing of information must be performed
                            in a complete, accurate, concise, and user friendly manner.
                      2.  The students will present a component of the salt marsh and describe its
                            structure and function.
                           Theme 1.5:  An essential aspect of science is the at of accurately and effectively
                            conveying oral, written, graphic, or electronic information from the preparer to the user.


Engage:  Take five minutes and write everything you can think of about salt marshes.

Explore:  Look at the following picture and predict why it is a salt marsh.



Explain:
Coastal salt marshes develop along the intertidal shores of bays and estuaries. Estuaries occur where a river meets the sea, and
the water is somewhat brackish. In general, salt marshes along the Northern California coast have a relatively low salinity
because of substantial river runoff, whereas those along the southern coast, where there are fewer rivers and less runoff, are of
higher salinity. San Francisco Bay contains the largest and one of the most complex salt marsh systems in the state.

Salt marsh plants are adapted to a harsh, semi-aquatic environment and saline soils. Species diversity is low. Stout stems, small
leaves, and physiological adaptations for salt excretion and gas exchange characterize the inhabitants of the salt marsh, which
are mostly grasses and low perennial herbs. The tangle of marsh plant roots and stems helps to stabilize the muddy bottom, as
well as to trap debris and dissolved nutrients with each tidal cycle. Bacteria convert this oasis of detritus into food resources for
microscopic algae, invertebrate larvae, and larger animals. Salt marshes are about twice as photo-synthetically productive as
corn fields and provide critical nursery grounds for numerous organisms.

Species composition and zonation in the salt marsh are governed by salinity gradients in combination with the amount of
intertidal exposure. Eelgrass, Zostera marina, for example, occupies the lowest or most marine zone. It cannot tolerate a
freshwater environment or intertidal conditions that would expose its roots to air. Cordgrass, Spartina foliosa, occurs in the
marine-to-terrestrial transition zone, characterized by lower salinity and periodic exposure to the air. Shoreward, where
conditions are even drier, pickleweed species belonging to the genus Salicornia are common. On higher ground, where tidal
intrusions are rare, the wiry, prickly-leaved succulent jaumea, Jaumea carnosa, is common, as are the bushy shoregrass,
Monanthochloe littoralis; tall and slender sea arrowgrass, Triglochin maritima; and endangered salt marsh bird's beak,
Cordylanthus maritimus. The green, wiry-leaved saltgrass, Distichlis spicata, is widespread, occurring from the middle to
high marsh, as well as in dunes and on salt flats. An unusual salt marsh plant is the orange, parasitic dodder, Cuscuta salina. Its
tiny, scale-like leaves and thread-like stems frequently invade and cover large areas of vegetation.


Elaborate:  Click on the following link and take the salt marsh field trip.  www.tramline.com/tours/salt/_tourlaunch2.htm

Evaluate:  What do you know about salt marshes?

                   How would you explain the components of a salt marsh?

                   What do you know about plants living in salt marshes?


Glossary:  Estuaries:  type of wetland that consists of a delicated mixture of salt water and freshwater

                 Salt Marsh:  type of wetland that consists of salt water and a variety of grassy hydrophytic vegetation

                  Spartina alterniflora:  a type of cord grass found in salt marshes


References:  Tennessee State Science Framework

                       www.ils.unc.edu/parkproject/maritime.html

                      www.tramline.com/tours/salt/_tourlaunch2.htm

                      Olsen, Margaret M.  "Sapelo Island-Geogria's Coastal Treasure".