Flathead at Shelly Beach, NSW by Gergo RugliOriginal Source: www.rugliphoto.com
What is a seaweed?
Seaweed is a diverse group of photosynthetic, plant-like marine algae that provide essential habitats and food for many ocean creatures.
Seaweed Diversity and Southern Rock Lobster by Stefan AndrewsOriginal Source: @ocean_imaging
Did you know?
Australia's Great Southern Reef has the highest level of species richness and endemism of seaweed flora in the world.
Seaweed Diversity by Stefan AndrewsOriginal Source: @ocean_imaging
The colour of seaweed
Seaweeds are grouped into three main colours: red, green and brown.
Red
The most diverse of the seaweeds, there are more than 800 species of red seaweed in the world, and over 75% of them are found nowhere else but on Australia's Great Southern Reef.
Green
Green seaweed thrives in shallow water where they are able to absorb red light and reflect their green chlorophyll pigment.
Brown
Brown seaweeds, like giant kelp (macrocystis) and golden kelp (ecklonia radiata) are canopy forming and are the backbone of the Great Southern Reef, the temperate reef system spanning over 8000km of Australia's southern coastline.
Kelp and Fish by Stefan AndrewsOriginal Source: @ocean_imaging
Kelp: A firm foundation
Scientists refer to kelp as a 'foundation' species because they create habitats that benefit other organisms.
Bull Kelp in Motion by Stefan AndrewsOriginal Source: @ocean_imaging
Bull Kelp
Attaching to rocky reefs by a large disc-shaped holdfast, the brown leathery branches of Bull Kelp (Durvillaea potatorum) can reach a lengths in excess of eight metres. Individual bull kelps can weigh up to 75kg!
Golden Kelp
The golden kelp (ecklonia radiata) form the backbone of the Great Southern Reef.
With strong holdfasts gripping tightly to the shallow, rocky surfaces, these highly productive algae dance gracefully in the high swell conditions where they flourish.
Golden Kelp. Australia's Great Southern ReefGreat Southern Reef Foundation
Giant Kelp
Giant kelp (macrocystis) is the iconic canopy forming seaweed that grows over 35 metres long and up to half a metre each day.
Like trees in a forest, giant kelp modifies the environment and the resulting conditions favour a huge diversity of other species.
Golden kelp washup on beach by Stefan AndrewsOriginal Source: @ocean_imaging
Seagrass vs. Seaweed
Do you know the difference?
Seagrass
Seagrasses are the only flowering plants that grow in marine environments.
Similar to plants on land, seagrasses have roots, stems and leaves, and produce flowers and seeds.
Seaweed
Seaweeds don't have leaves or roots – instead, every part of the seaweed can absorb nutrients and take in energy from the sun.
Instead of being rooted in the ground, they are anchored to rocky reefs or hard substrate with a root-like claw called a holdfast.
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Imagery by Stefan Andrews and Gergo Rugli.
