'KelpWatch' - Monitoring Giant Kelp Forests in Tasmania
Photo by: Jon BryanPhoto by: Jon BryanPhoto by: Jon BryanPhoto by: Jon Bryan

About 'KelpWatch'
Kelp Survey Form
Kelp Facts
Kelp Forests
Kelp in Tasmania
Decline of Kelp
What are Kelps?
Biology of Kelp
Ecology of Kelp
Kelp Inhabitants
Other Kelp Sites

Kelp Harvesting  

Biology of Giant Kelp

Giant Kelp (or Macrocystis) has the distinction of being the largest marine plant (and seaweed) in the world; with the largest attached plant recorded being 65m long. The kelp plant has a root-like holdfast that fixes to rocky surfaces; a long slender stalk or stipe; and long, leaf-like blades or fronds, that are the major site of photosynthetic activity.

The kelp plant is supported in the water by gas-filled bladders on each frond called pneumatocysts. The holdfast is cone-shaped and can grow up to 60 cm in diameter in large plants.

Kelp Morphology

Diagram of Kelp Morphology


Giant Kelp have an unusual life history - a hetermorphic alternation of generations - comprising a diploid (2n) sporophyte generation (which forms the large leafy plants), which produces spores that develop into the microscopic haploid (n) gametophyte generation (comprising male and female gametophytes). These microscopic plants on the seafloor fertilise to give rise to the leafy sporophyte.

Kelp Life Cycle

Kelp Life Cycle

The spores are found in sori located on the blades, within special blades called sporophylls, located at the base of the plant (branching off the stipes just above the holdfast). A single adult plant can produce many sporophylls, each sporophyll containing billions of spores.

Photo by M. Readdie
Kelp sprophyll
(Photo by: John Heine)


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Enquiries and feedback: Karen.Edyvane@utas.edu.au
URL: http://www.geol.utas.edu.au/kelpwatch/   Last modified: 10. December 2001