Bringing kelp forests back to life

Bringing kelp forests back to life

Wed, 17/08/2022 - 13:52
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Kelp forest ecosystems are declining around the world. In response, marine managers are working to restore and counteract these declines.

Macrocystis pyrifera, commonly known as giant kelp or bladder kelp, is the largest of all algae.

Giant kelp grows in dense stands known as kelp forests. Kelp forests, defined here as habitat-forming brown algae in the orders Laminariales, Fucales, and Desmarestiales, are globally distributed habitats which have declined around the world

Kelp forests, defined here as habitat-forming brown algae, have a really important job in maintaining water quality in coastal areas. Thriving stands of giant kelp, which grows up to 40 metres high and at a pace of up to half a meter a day, provide habitat for fur seals, seahorses, weedy sea dragons, rock lobsters, abalone and fish.

Killed off

In Tasmania the once thick underwater forests off the east coast used to be so dense they were marked as shipping hazards on nautical charts. But since the 1960s, Tasmania’s giant kelp has all but vanished. Most of it has been killed off by warm waters pushed southwards by the east Australian current.

Restoration efforts provide hope the precious habitats can be rejuvenated along with their associated ecosystem services. According to a recent analysis of kelp projects spanning 1957 to 2020, restoration efforts around the world are increasing in frequency.

Coral reefs and the Great Barrier Reef get a lot of attention, and a lot of funding,” Dr Cayne Layton, of the University of Tasmania’s Institute of Marine and Antarctic Studies, told the Guardian. “Kelp forests and many other temperate, or cold water, marine ecosystems really suffer from an ‘out of sight, out of mind’ kind of mentality.”

Heat-tolerant plants

Dr Layton's team has grown and planted giant kelp that is naturally more tolerant of warm water – up to 4C more heat-resistant than average. He hopes the heat-tolerant plantings could be more resilient to low nutrients.

In addition to their ecological benefits, kelp forests are also economically and culturally significant.  Kelp is estimated to generate $100,000 USD a hectare a year, amounting to billions of dollars annually. It is harvested and refined to yield alginates, compounds used widely as a thickener in foods and cosmetic products.

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