Succulent plants that absorb salt into their tissues until they burst. The samphire marshes store carbon in saltwater soils where it can't decompose, creating carbon sinks.
Melburnian, CC BY-SA 3.0, via Wikimedia Commons
The Saltwater Specialists
The salt marshes of Torrens Island, north of Port Adelaide, are dominated by a group of hardy succulents called samphires. These plants, including species from the Tecticornia genus like the Shrubby Glasswort (Tecticornia arbuscula), thrive in conditions that would kill most other vegetation. They are halophytes, or salt-tolerant plants, with a unique strategy for survival in the saline mudflats. Instead of preventing salt from entering their tissues, they actively absorb it and store it in vacuoles, specialized compartments within their cells.
This process allows the plant to maintain a water potential gradient, enabling it to draw water from the salty soil. The salt accumulates in the fleshy, articulate stems. As older stem segments become saturated with salt, they are shed from the plant, effectively removing the excess salt from the organism. This constant cycle of absorption and disposal allows the samphire community to flourish in the intertidal zone, an environment subject to regular inundation by seawater. The plants themselves can grow up to 2 meters tall, forming a low shrubland that is common in the area.
Blue Carbon Powerhouse
Besides their salt-handling abilities, the samphire marshes of Torrens Island perform an important climate-regulating function is a "blue carbon" sink. Blue carbon is the carbon captured and stored by coastal and marine ecosystems. These coastal wetlands can store up to four times more carbon per area than terrestrial forests. The carbon sequestration process happens in the waterlogged, anoxic (oxygen-poor) soils of the marsh.
When the samphire plants die, their organic matter is buried in the sediment. The lack of oxygen slows down decomposition to a near halt, meaning the carbon within the plant tissues becomes trapped in the soil for potentially hundreds or thousands of years. This makes the protection and restoration of these habitats an important tool for climate change mitigation. The Torrens Island Conservation Park, which covers about three-quarters of the island, is a protected area for these valuable saltmarshes and mangrove ecosystems.
The island is part of the Adelaide International Bird Sanctuary, an important stopover point on the East Asian-Australasian Flyway. This migratory route is used by over five million birds annually. Every year between September and March, up to 27,000 shorebirds visit the sanctuary to feed and roost, including vulnerable species like the curlew sandpiper and the red knot. The marshes provide food in the form of worms, shrimp, and other invertebrates, supporting this vast avian population.
💡Fun Facts
The name "samphire" is an English alteration of the French "herbe de Saint-Pierre" (St. Peter's herb), named for the patron saint of fishermen.
Some species of samphire are edible and are also known as sea asparagus; they were pickled and eaten by convicts on their way to Australia to prevent scurvy.
The marshes are important habitat for the vulnerable slender-billed thornbill, also known as the samphire thornbill (*Acanthiza iredalei rosinae*).
Blue carbon ecosystems like saltmarshes can capture and store carbon much faster than terrestrial forests.
There is no public vehicle access to Torrens Island Conservation Park. The island itself is generally closed to the public, though the causeway may be accessible. Access to some parts of the park is possible via small watercraft.
Admission
Free to access surrounding waters.
Accessibility
The terrain of the island is flat, consisting of saltmarsh, mangroves, and coastal dunes. Access is by watercraft and there are no jetties or mooring facilities.
