From the Marine Scientist

Seaweeds are either green, brown, or red algae and have a multitude of forms ranging in size from microscopic filamentous to the largest: Macrocystis pyrifera which has been reported to reach lengths of more than 30m.

 

Southern Australian temperate waters are characterised by an exceptionally diverse benthic seaweed flora with over 1400 species recognised. Of these, approximately 16% are green, 24% are brown and 60% are red algal species. So far, more than a third of these species have been identified in the Tasmanian flora with a number of endemics making macroalgal communities here very diverse and deserving of special recognition.

 

Within the last 30 years, the Japanese macroalga Wakame (Undaria pinnatifida) has become part of the Tasmanian flora. The alga was first identified at Orford in 1988. The alga can be abundant on rocky reefs in wave sheltered waters and its distribution now extends from the south of Tasmania to Victoria on the Australian mainland. This alga is cultured in Japan where it is valued as a food. In Tasmania, Marinova has established a market for fucoidans, bioactive polymers extracted from this alga. The alga is harvested from established wild populations.

 

Other recent and more significant changes to the flora include the loss of String kelp (Macrocystis pyrifera) forests from Tasmania's east coast and the devastation to kelp bed communities in Tasmania's north east as a result of the increasing abundance of the long spined sea urchin: Centrostephanus rodgersii. Both these changes are believed to be due to warming waters as a result of global warming and will impact on dependent animal species such as commercially harvested abalone and rock lobster.

 

Seaweed species are generally an unappreciated and integral part of marine ecosystems. This picture book presents some of Tasmania's seaweed species in their best light. Enjoy.

 

 

Dr Craig Sanderson

Senior Marine Biologist, Institute for Marine and Antarctic Studies, Tasmania