Earth’s oceans are home to some of the most extensive forests found anywhere on the planet. Hidden underwater are huge kelp and seaweed plantations, whose lush canopies are home to huge numbers of marine species. One of the most notable is the giant kelp forests of Australia’s Great Southern Reef, which straddle five states and are the habitat of fairy penguins, octopuses, jellyfish, sea lions, leafy seadragons and red handfish, among many other species. But unlike the iconic Great Barrier Reef, most people have never heard of it.
These magnificent giants once swayed in vast numbers with the ocean’s currents, flickering gold in the sunlight and skimming along the water’s surface. Giant kelps can grow up to 40 m high; however, they have slowly disappeared, declining by over 95 per cent in Tasmania since the 1970s.
Here’s all you need to know about this fragile ecosystem and how new forms of technology—like artificial intelligence (AI)—are helping them thrive.
Underwater forests are formed by seaweeds, which are types of algae. Like other plants, seaweeds grow by capturing the Sun’s energy and carbon dioxide through photosynthesis. Over 70 per cent of the world's oxygen comes from seaweeds and algae.
Seaweeds are grouped into three main colours: red, green and brown. There are more than 800 species of red seaweed in the world, with over 75 per cent of them found nowhere else but on the Great Southern Reef.
The giant kelp (Macrocystis pyrifera) is a species of brown seaweed. It grows in cold, shallow seas around the world, from California to New Zealand. At its base, the giant kelp has a holdfast that attaches to rocks or hard substrates on the sea floor. Long stems, called stipes, grow toward the surface, while leaf-like blades grow along the stipes, with gas bladders at their base to help them float.
Where there is kelp, there is marine life. Thousands of species depend on these underwater rainforests for food, nurseries and shelter. These include sea otters; abalone, a type of marine snail; sea dragons; the giant Pacific octopus; harbour seals, who can be found playing among the kelp forests; and cuttlefish.
The climate crisis is threatening the few remaining strongholds of giant kelp in Tasmania, bringing warmer, nutrient-poor waters to the island. This is a problem because the species is susceptible to warmer water and vulnerable to attack by a sudden imbalance of sea urchins. Today, the giant kelp forest is listed as an endangered marine community type.
But, there is hope. The Commonwealth Scientific and Industrial Research Organisation (CSIRO), the Institute for Marine and Antarctic Studies (IMAS), The Nature Conservancy, the Great Southern Reef Foundation, the Kelp Forest Alliance and technology giant Google announced a new project and partnership in 2024 to help preserve and restore Australia’s giant kelp forests using AI.
The project will utilise Google Earth Engine and Google Cloud’s AI platform Vertex AI to locate and analyse kelp forests in more than 7,000 sq km of satellite imagery for the first time. This will provide researchers with a complete picture of these forests so that they can build an efficient, reliable and long-term monitoring strategy.
In addition to this, the CSIRO, IMAS and Google researchers will use AI to analyse the surviving giant kelp to understand what makes some of it heat resistant. Using two Google AI tools—DeepConsensus and DeepVariant—they will aim to identify the genetic patterns that lead to heat resistance, allowing scientists to grow these varieties and ultimately restore the kelp forests.
As a first-of-its kind, this research project won’t just make a difference in Australia, but could have a positive impact globally. To support the restoration of giant kelp forests nationwide, the geospatial map will be accessible to all scientists, while the AI research tools used are already available open-source.
Besides this, scientists are building a biobank of giant kelp gametophytes to grow strains that are naturally more tolerant of warmer waters. Like growing plants in a nursery, the giant kelps are grown in the lab until they are ready to be planted on lengths of string in the ocean.
During the first trial, tiny babies of giant kelp less than one mm long were planted in the ocean at sites off Tasmania's south-east coast. One year later, they were 12 m tall. The result was a giant kelp forest—a new home for the sea creatures that live in this once vast habitat.
The restoration of giant kelps is crucial to increasing the habitat for many of Tasmania’s marine species. It will also help recreational user groups, like local dive operators and commercial fisheries, by supporting job creation in regional coastal areas.
