Tag Archives: Delesseriaceae

Vanvoorstia bennettiana (Harvey) Papenfuss

Bennett’s Seaweed (Vanvoorstia bennettiana 

Bennett’s Seaweed is probably the first marine algae species that was officially declared extinct.  

This very small red alga species was described in 1859, it may probably always only have occurred on two places within the harbor of Sydney at the coast of New South Wales, where it apparently was still quite common at the time when it was discovered.  

The extinction of this species was caused by various human activities that led to a pollution of the water with suspended sediments which again were blocking the very fine clathrate branches of the algae, resulting in the inhibition of photosynthesis and causing the dead of the plants.  

The last living examples were found in 1886.  


Depiction from: ‘William Henry Harvey: Phycologia Australica; or, A History of Australian Seaweeds; comprising coloured figures and descriptions of the more characteristic marine algae of New South Wales, Victoria, Tasmania, South Australia, and Western Australia and a synopsis of all known Australian algae. London, L. Reeve 1858-63’  

(not in copyright)


edited: 21.03.2018

Phycodrina elegans (Setchell & N. L. Gardner) M. J. Wynne

Elegant Red Alga (Phycodrina elegans)

The elegant Red Alga was a marine algae species that was endemic to the ocean surrounding the Galápagos Islands, and it appears to have been very common in former times.

The species disappeared after or during a devastating El Niño event that took place between 1982 and 1983. However, the removal of lobsters and other fish predators from the environment by local fishers lead to a cascade of direct and indirect effects involving explosive population expansion of grazing (algae-feeding) sea urchins.

This again lead to the complete extinction of several endemic marine algae species from the waters around the Galápagos archipelago that happened almost unnoticed by the public.



[1] Graham J. Edgar; Stuart A. Banks; Margarita Brandt; Rodrigo H. Bustamantes; Angel Chiriboga; Lauren E. Garske; Peter W. Glynn; Jack S. Grove; Scott Henderson; Cleve P. Hickman; Kathy A. Miller; Fernando Rivera; Gerald M. Wellington: El Niño, grazers and fisheries interact to greatly elevate extinction risk for Galapagos marine species. Global Change Biology 16: 2876-2890. 2010

Photo: Macroalgal Herbarium

(under creative commons license (3.0))


edited: 29.11.2018