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Protecting our vast underwater forests

11 June 2021

The world's giant kelp forests – vital marine wildernesses as important to Earth’s ecology as rainforests and coral reefs – are being mapped by a team of international scientists.

University of Queensland PhD candidate Nur Arafeh-Dalmau is leading the project to map and identify potential sanctuaries for giant kelp forests, which are increasingly threatened by climate change.

“Marine kelp forests are found off 25 per cent of the planet’s coastlines,” Mr Arafeh-Dalmau said.

“They’re one of the most productive and magnificent ecosystems on Earth, but they’re disappearing because of an increase in human activities and marine heatwaves.

“Giant kelp is the fastest growing organism on Earth, and when we lose a forest, we’re losing incredible carbon store, habitat for marine biodiversity, breeding grounds for fish stocks and an erosion buffer for coastal communities.

“As marine heatwaves increase in frequency and severity, we need to work out how and where to best protect them.

“We’re working hard on this very problem, monitoring where kelp forests thrive over time and quantifying how much of these persistent kelp habitats are fully protected.”

The research team analysed 35 years of satellite data information – identifying areas where giant kelp forests act as potential climate refuges and calculating how much protection is needed.

The mapped region covers thousands of kilometres along the USA and Mexico coastline and islands of the Northeast Pacific Ocean.

“We found there’s an alarmingly uneven level of protection of kelp forests inside marine reserves in the region, with less than one per cent protected off Mexico’s Baja California coast,” Mr Arafeh-Dalmau said.

“This region is subject to episodes of higher sea surface temperatures and lower availability of nutrients, limiting the kelp’s biomass and spread.”

The study methods will now be used worldwide to map the persistence of giant kelp and other canopy forming kelp species in countries like Chile and South Africa, and Australia and New Zealand.

Mr Arafeh-Dalmau believes one of the biggest barriers to kelp forest conservation is the lack of awareness, particularly when compared to similar ecosystems such as coral reefs.

“We need the public and policymakers to know these mysterious underwater forests exist, they’re being threatened globally by human activities, and we need to protect them now.”

Co-author Dr Fiorenza Micheli from Stanford University said governments needed to ensure 30 per cent of oceans were fully protected by 2030, including large portions of kelp forests.

“Protecting persistent kelp forests and determining where forests can act as climate refuges is imperative,” Dr Micheli said.

“But other measures will be necessary including restoration of degraded kelp forests, identification of genetically resilient kelps for targeted protection and restoration, and a reduction of other anthropogenic stressors like overfishing and pollution.”

The international team includes Associate Professor Kyle Cavanaugh and PhD Candidate Kate Cavanaugh from the University of California - Los Angeles, Professor Hugh Possingham from The University of Queensland, Dr Adrian Munguia-Vega from the University of Arizona, Professor Gabriela Montaño-Moctezuma from Universidad Autónoma de Baja California, and Dr Tom Bell from the Woods Hole Oceanographic Institution.

The research is published in Communications Earth & Environment (DOI: 10.1038/s43247-021-00177-9).

Mr Arafeh-Dalmau has support from The University of Queensland, the Fundación Bancaria ‘la Caixa’ under a Postgraduate Fellowship, and a Estate Winifred Violet Scott research grant.

Image above: Kelp underwater.