Salt Marsh

Salt
Marsh

Listed below are ecologically important organisms that are commonly found in a salt marsh near Point Judith, RI (approximately 10 miles from the URI campus). Click on each thumbnail to view an enlarged image! Note that the precise composition of organisms may vary for other marshes.

Spartina alterniflora Cordgrass Tall, stiff-stemmed grass, growing throughout the low marsh. Taller specimens (up to 1.2 m) are found closer to water's edge. Possesses a round stem with flat, alternate leaves. Thrives in poorly flushed semidents by transporting oxygen to its roots through its leaves and stems.
Spartina patens Salt-meadow hay Soft, light green grass that forms thick mats in the high marsh. Grows up to 30 cm, with rolled, rounded leaves. Possesses a ball joint at the base of the stem to prevent breakage during tidal flow. This species was once mown for hay, hence the name.
Juncus gerardii Black rush Deep green grass forming dense turfs up to 40 cm tall. Dominates the upper high marsh, where it is flooded only by the most extreme tides of each month. The stems and leaves of this species are round and sharp enough to puncture skin.
Distichlis spicata Spikegrass Grey-green, widely-spaced grass up to 30 cm tall with flat, short leaves. This plant rapidly colonizes new areas through below ground runners. Forms patches in the lower high marsh, often with Salicornia.
Limonium carolinianum Sea lavender 60 cm tall branching stem with several spoon-shaped basal leaves at base. Possesses numerous tiny purple flowers from July to September. Grows individually in the upper intertidal zone.
Salicornia europaea Slender glasswort Succulent green annual, which turns deep red in the fall. Extremely tolerant of high salinity, it is often the first plant to colonize bare patches of the high marsh. It is very salty to the taste and is often added to salads or pickled.
Phragmites australis Giant reed 3 m tall reed with a brown stem and 3 cm wide green leaves. Possesses a tuft at the top when mature. An introduced species, it dominates brackish to fresh water marshes, especially in areas disturbed by man. It has spread to the point of becoming a nuisance.
Zostera marina Eel grass Subtidal flowering plant with true roots, stems and leaves. Green leaves grow to 1 m long and 1 cm wide. Plays a vital role in the estuary by providing sediment stability and habitat for numerous species.
Ulva lactuca Sea lettuce Bright green, translucent sheet, often with ruffled edges. Blades are two cell layers thick and may grow to 1 m, although usually shorter. Thrives in disturbed and polluted waters.
Littorina littorea Common periwinkle Snail with brown, black, or gray shell that is rounded and up to 3 cm long. Shell spire usually worn and rounded in larger specimens, pointed in smaller ones. Found at base of saltmarsh plants grazing on thin algal films.
Crepidula fornicata Common Atlantic slipper snail A scoop-shaped shell up to 5 cm long with a shelf extending half-way across the opening. In living organisms, the shelf is obscured by tissue. Found in shallow water in stacks one on top of the other with the larger females on the bottom, hermaphrodites in the middle and smaller males on top.
Ilyanassa obsoleta Eastern mudsnail Grey, black, or dark brown snail 2.5 cm long, often covered with a fuzzy or mold-like covering. Patrols mudflats for dead organisms and may congregate to feed by the dozens.
Mya arenaria Soft-shelled clam Oval-shaped, white bivalve up to 4 cm long. Siphon is very long and cannot be retracted into shell. Commercially known as steamers, this clam is frequently steamed and eaten.
Mercenaria mercenaria Quahog A heavy-shelled bivalve with concentric rings, which wear down with age. Shell is white to gray and up to 13 cm long. Burrows in soft sand or mud bottoms, exposing only its siphons to filter water for microorganisms and small food particles. They are called littlenecks or cherrystones when small.
Geukensia demissa Ribbed mussel Yellow-brown mussel with radiating ribs, up to 10 cm long. Found partially buried in salt marshes attached to peat and roots of Spartina alterniflora. Their feces are a significant source of fertilizer to Spartina.
Crassostrea virginica Eastern oyster A filter-feeding bivavle with an irregular, asymmetrical, grayish shell up to 15 cm long. Attaches to rocks, pilings, and other oysters in brackish often polluted waters. Has supported a large commercial fishery for over 100 years.
Argopecten irradians Bay scallop Bivalve with ribs radiating from hinge toward opposite edge of shell, up to 8 cm long. Possesses very strong adductor muscle, which it uses to open and close its shell to "jet" away from predators. Adductor muscle is sought after as food. Attaches to Zostera marina during the early part of its life cycle.
Uca spp. Fiddler crab Small, semi-terrestrial crab, up to 3 cm in width, which digs burrows in the mud under Spartina. Male has an enlarged claw, which he slowly waves in the air to attract females. Feeds on detritus and aerates the marsh sediments with their burrows.
Limulus polyphemus Horseshoe crab Olive-green to brown crab up to 60 cm long with long spike-like tail. Female is larger than male. An ancient species harmless to man, it is often used to bait lobster and fish traps.