‘Deforestation of the Sea: A closer look at valuable kelp forests in shallow seas around Britain’ by Jess Fisher.
‘I can only compare these great aquatic forests… with the terrestrial ones in the intertropical regions. Yet if in any country a forest was destroyed, I do not believe nearly so many species of animals would perish as would here, from the destruction of the kelp’
Charles Darwin (1834) Tierra del Fuego, Chile
Kelp forests: the rainforests of the ocean
A few weeks ago, I settled happily into Finding Dory on a Saturday night. Towards the end, the little blue fish drifts through the giant kelp forests, devoid of life, and sadly proclaims ‘…there’s nothing here but kelp!’. Having studied this oceanic plant, I can confirm that this is 100% scientifically incorrect: well done Pixar.
Kelp forests actually have around the same levels of biodiversity as a tropical rainforest. But why should you care?
Because kelp can do everything: it’s home to hundreds of thousands of marine species, it can be used as a fertiliser and a biofuel, it can be extracted to use in cosmetics like make-up and toothpaste, amongst many more uses. In 1908, Japanese biochemist Professor Ikeda isolated monosodium glutamate (or MSG – one of the things that makes Asian food so great) from kelp. Who knew science could be so delicious?!
Why is kelp disappearing?
Unfortunately, kelp is reported to be disappearing. This is mostly because of climate change making the oceans uninhabitable for some species, but also that more people are harvesting kelp from the wild. Lots of people are even beginning to call it a superfood. While its rapid growth rate (up to half a metre per day in some species) suggests that harvesting kelp should not really be a problem, conservation scientists are worried that all the marine life living in kelp forests will take quite a bit longer to return. Britain is especially important for kelp (because of the variation in habitats and rocky shores) which is why I started working on a project looking to test novel monitoring methods for kelp, so we can potentially measure what is actually happening.
How our project works
Kayaking into the open ocean near Plymouth, we fought through choppy waves into a prevailing wind, whilst I continually threw cold seawater with my paddle onto my kayak-partner, who was sitting behind me! Lots of kelp lives in the subtidal zone (beneath the sea surface even at low tide), and so the plan was to beam sonar onto the seabed from a kayak, look at the graph that the sonar gives back, and then use a GoPro camera to visually verify assumptions that we were making about which graphic patterns denoted kelp. For example:
This was one of four kayak trips the team made to test the method. Amongst some other objectives, the main aim is to ask whether sonar can be used to monitor kelp at a Britain-wide scale. The findings will be given to our funder, The Crown Estate, who manages development on the British coastline (The Crown Estate is owned by the Queen of the United Kingdom). They would like to eventually create some guidelines for sustainably harvesting wild kelp, so that this valuable seaweed resource (and its associated flora and fauna) will be available for future generations for years to come. Some kelp snapshots from the seabed:
Counting the cost of losing kelp forests
Kelp forests are reported to be worth billions of pounds. In the northeast Atlantic, young lobster live in the kelp, and are eventually fished by a lobster industry worth £30 million alone. Is it worth keeping? Certainly. Is it worth monitoring incase of declines? Definitely.