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The underwater forests of Kelp

Palaeobotany and art to discover an unexpected ecosystem

Alessandra Navazio
a story by
Alessandra Navazio
The underwater forests of Kelp

Kelp forests first appeared more than 32 million years ago. Formed by a specific type of brown seaweed, they are a rich underwater habitat teeming with biodiversity. The Museum of Underwater Sculpture, in Cyprus, recreates this ecosystem, urging us to imagine new sustainable futures.

«I have been working on it for 20 years in different places around the world, it is my favourite thing to do: to go at night among the seaweed, turn off the lights and walk. It feels like I’m in a forest and I forget I’m underwater», says Jason deCaires Taylor, underwater sculptor and photographer, describing kelp forests, one of the most diverse ecosystems on Earth. Capable of absorbing about 20 times more carbon per acre than forests on land, these underwater forests also release oxygen and help mitigate ocean acidification in coastal waters. According to paleobotanist Cindy Looy’s research, kelp forests emerged over 32 million years ago and still today, swaying to the rhythm of the ocean waves, they teach us the art of hospitality and imagination.

The origins of Kelp forests

Kelp is a special type of algae and Kelp forests are formed by these large brown algae of the order Laminariales: 27 different genera that grow in dense stands along rocky shores in shallow, cold, or temperate waters. They are found in latitudinal bands between 40 and 60 degrees in both hemispheres: from the North Atlantic to the South Atlantic, as well as in the Pacific and Indian Oceans, from Alaska to Canada, through Sweden and Norway. The exact distribution of these algae, however, changes annually, expanding or contracting by tens, if not hundreds, of kilometers in a short time. In height, they range from a few meters to 45 meters, forming forests similar to those on land or covering the seabed with “leaves”1.

The underwater kelp forests similar to woodlands are known as canopy kelp, floating thanks to rigid, gas-filled structures, while those covering the seabed are prostrate kelp, which do not float as they lack rigid structures to keep them upright. These 27 genera differ in morphology, height, and distribution but share a common trait: being a single organism and, simultaneously, the habitat for many others. The algae form a three-dimensional structure capable of «forming the foundation of rich marine ecosystems with a variety of animals, including sea otters, fish, sea urchins, crabs, and other invertebrates», says Cindy Looy, a biologist at the University of Berkeley, who discovered the oldest kelp forests.

Cindy Looy is a professor in the Department of Integrative Biology at the University of Berkeley. She studies the response of plants and plant communities to major environmental changes and their evolutionary consequences. Her primary interest is investigating aspects of the terrestrial biotic crisis at the end of the Permian, the last period of the Paleozoic era, and its aftermath.

Scopri la sua ricerca sulle foreste di Kelp

Looy’s discovery came after over a decade of research: «My friend, paleobiologist Steffen Kiel» recalls Looy, «showed me some holdfast fossils», which is a root-like structure to which various aquatic organisms such as seaweed and sponges attach. «These fossils were collected by amateur collector James Goedert on a beach near Jansen Creek in Washington State». Goedert, who had occasionally collaborated with Looy, found something resembling kelp algae in these fossils: «That’s when I started to study these forests, which are incredibly complex because I wanted to find out how and when they originated».

Looy, Goedert, and Kiel authored a study published this year2, demonstrating that the brown algae off the northwestern Pacific coast date back over 32 million years to the Cenozoic era. «Before everything else can emerge», says Looy, «the foundations of the entire system are needed». Long before the appearance of modern marine mammals, sea urchins, birds, and bivalves, the kelp forest already existed.

Some pictures from the Berkeley News Centre website, in order (image 1) a Pacific seal swims in a kelp forest in Monterey Bay, California, photo by Cindy Looy/UC Berkeley; (image 2) the hanging of a kelp from Pacific Grove beach, California, photo by Cindy Looy/UC Berkeley (image 3) the coastal area of Washington’s Olympic Peninsula, where most of the fossil carcasses were collected by palaeontologist James Goedert, photo by Steffen Kiel; (image 4) timeline illustrating the evolution of kelp forests and associated organisms along the Pacific coast over the past 32 million years, along with changes in water temperature. Black bars indicate members of modern, complex kelp ecosystems: sea otters, abalones, sea urchins and, until recently, sea cows. The green bars indicate now-extinct members of early kelp beds, including desmostilians and penguin-like plotopterids, image by Steffan Kiel, Cindy Looy and Rosemary Romero. All rights reserved. Reproduced with permission of the author.

Kelp forests as a refuge

«The number of living creatures of all orders, whose existence intimately depends on algae, is marvelous»: as early as 1845, Charles Darwin3 realised that the evolution of life, and thus the kelp forests themselves, is far more complex and wonderful than biological data alone can estimate. «In the last 32 million years, numerous animals have appeared and disappeared from kelp forests» Looy claims «and only in the last few million years» —a very short time from an evolutionary perspective— «the kelp forest ecosystems we know today have evolved».

The kelp forest ecosystem is like a matryoshka that houses organisms adapted to different levels of light and nutrients on three parts: the leaf, the stem, and the root, which can in turn host other, even smaller organisms. This matryoshka thus forms an environment protected from external disturbances, a refuge of biodiversity compared to the open sea.

«I like how kelp forests interact with light, how they encourage many species to hide within, creating an oasis of life», says environmental sculptor and photographer Jason deCaires Taylor. Drawing inspiration from kelp forests and their “hospitality”, deCaires Taylor conceived MUSAN (Museum of Underwater Sculpture) housing over 96 artworks in Ayia Napa, on the southeastern coast of Cyprus. «Canopy kelp forests are fascinating: there are all the creatures on the seabed, like crustaceans, but also many fish varieties along the water column, living at different heights», Taylor continues. «I’ve been studying them for a while, focusing on their structure, the way they work, the air pockets that keep them afloat. In MUSAN’s underwater installations, I wanted to recreate a kelp forest I saw in the Norwegian Sea». The result was the creation of a marine forest, the first of its kind, where «the same environment of a tropical rainforest is reproduced underwater», the sculptor explains.

Jason deCaires Taylor, born in 1974 to an English father and Guyanese mother, is an award-winning sculptor, environmentalist, and professional underwater photographer. After graduating from the London Institute of Arts in 1998 with a BA Honours in Sculpture, Taylor was the first of a new generation of artists to transfer the concepts of the Land art movement to the marine environment. Over the past 17 years, Taylor has created underwater museums and sculpture parks, submerging over 1,200 living artworks in oceans and seas worldwide.

Discover MUSAN

MUSAN, the result of a joint effort by the Department of Fisheries and Marine Research, the Municipality of Ayia Napa, and the Cyprus Ministry of Tourism, was created within the National Strategy for the Creation of Artificial Reefs4 to enhance fish stocks and safeguard the marine environment. «The idea is rewilding», Taylor explains, meaning transforming a barren stretch of sand into a lush environment rich in life, just like Kelp forests do. Taylor’s sculptures are therefore made of a special type of cement, similar to that used by the Romans hundreds of years ago, reinforced with stainless steel and basalt, a material that does not change its properties over time. In fact, «the longer it stays underwater, the stronger and denser it becomes» Taylor explains

The sculptures don’t break down, they actually grow over time, in the sense that they are enriched with more layers of marine life.

The ph-neutral surface of the sculptures and their positioning creates space for marine life and encourages its colonisation. The problem with many forms of marine life, such as algae, corals, and sponges, is that «they need a fixed substrate to filter nutrients and live» Taylor explains. «On sand or silt, nothing can settle. Even kelp forests struggle. But by providing these platforms, we obtain a large area for marine life settlement».

A series of photos of the underwater installation created and photographed by Jason deCaires Taylor, #jasondecairestaylor. All rights reserved. Reproduced with permission of the author.

The “neverforest”

Taylor sees a kelp forest as «an opaque and unknown silhouette, a huge underwater forest capable of absorbing incredible amounts of CO2 and not very well known». Yet giant kelps, harvested from forests, are used extensively in every area of human life. They are the binding agent in food products such as ice cream and yogurt but also in toothpaste and lotions5, they are the food source for some commercially important animals, such as the mollusc Haliotis midae6. And again, in Asia, they are used in cooking and the most popular species are Saccharina japonica, or kombu seaweed, and Undaria pinnatifida, the famous wakame. It is no coincidence, in fact, that according to data7 held by the European Commission, China cultivated 20.1 million tonnes of seaweed in 2019.

Archaeological excavations8 show, then, that the kelp forests helped human beings survive, as early as 20,000 years ago, during the southward journey of the first peoples of the Americas, providing food for sustenance during migration.

If something does not exist, however, it can easily disappear without a trace, and this is precisely what is happening to the Kelp forests. Rising global temperatures, ocean acidification, and the decline in some areas of natural predators of herbivorous species such as crabs, starfish, seals, and otters are drastically altering their ability to recover and grow. «The installation is located within a natural marine reserve in the Mediterranean, which has been heavily exploited» Taylor points out, and this has led to an alteration of the balance of the ecosystem. The MUSAN sculpture forest has thus become a solution to repopulate the area. But there is more to it.

«Some people come to MUSAN thinking it is an archaeological experience and that they are visiting something ancient. Others arrive expecting a fun snorkeling adventure, but as they dive deeper, they discover something unexpected» Taylor explains.

«On land, when you enter a forest, you experience a range of emotions. There is the extraordinary light filtering through the trees, together with their movement revealing and concealing.

When one cannot, in fact, see the bigger picture, it is the imagination that starts to fill in the blanks.

Underwater, all these elements are amplified». The sculpture forest at MUSAN thus hosts not only «a second forest of marine inhabitants but also a third one» Taylor says «the one that our minds are capable of imagining». In the last series of sculptures one encounters in the museum, FEATHER STAR FOREST, Taylor’s favourite, all this is amplified «with the large root systems, the changing light throughout the day, and the currents blowing like a breeze on land».

In FEATHER STAR FOREST, there are golden oaks with leaves that dance and create light patterns along the water column, much like kelp forests. These are «golden hopes», Taylor says, that we can imagine to support the forest that is not there, that we do not know or see.

But which exists and has been home to a wide variety of marine organisms for more than 32 million years.


  1. For more on this topic see Smale, D. A., Burrows, M. T., Moore, P., O’Connor, N., & Hawkins, S. J. (2013). Threats and knowledge gaps for ecosystem services provided by kelp forests: a northeast Atlantic perspective, Ecology and evolution, 3(11), 4016-4038.

    Reed D. C., Kinlan B. P., Raimondi P. T., Washburn L., Gaylord B., e Drake P. T. (2006). A metapopulation perspective on the patch dynamics of giant kelp in southern California, Elsevier eBooks, 353–386.

    Steneck R. S., Graham M. H., Bourque B. J., Corbett D., Erlandson J. M., Estes J. A., e Tegner M. J. (2002). Kelp forest ecosystems: biodiversity, stability, resilience and future, Environmental Conservation29(4), 436–459. ↩︎
  2. For research by Looy, Goedert and Kiel see Kiel S., Goedert J.L., Huynh T.L., Krings M., Parkinson D., Romero R., and Looy C.V. (2024). Early Oligocene kelp holdfasts and stepwise evolution of the kelp ecosystem in the North Pacific. Proceedings of the National Academy of Sciences of the United States of America121(4). doi:10.1073/pnas.2317054121. The research was subsidized by the Advanced Light Source at Lawrence Berkeley National Laboratory and Deutsche Forschungsgemeinschaft ↩︎
  3. For more on the subject see Darwin, C. (1909). The voyage of the Beagle, P. F. Collier & Son, New York. ↩︎
  4. On the basis of the Artificial Reefs (AR) Strategy and within the framework of the implementation of the Operational Programme Sea 2014-2020, the Department of Fisheries and Marine Research (DFMR) has, through ministerial decrees, established six (6) Marine Protected Areas (MPAs) in which artificial reefs (ARs) have been placed. These areas extend from the coast to a depth of 50 metres and are located in Paralimni, Ayia Napa, Larnaca, Amathoonta, “Dasoudi” of Limassol and Geroskipou. Fishing with any fishing gear is prohibited in these areas. ↩︎
  5. On the use of algae as a binder, see Peteiro C. (2017). Alginate Production from Marine Macroalgae, with Emphasis on Kelp Farming, Springer series in biomaterials science and engineering, 27–66. ↩︎
  6. On the use of algae as a food source for some animals, see Rothman M. D., Anderson R. J., e Smit A. J. (2006). The effects of harvesting of the South African kelp (Ecklonia maxima) on kelp population structure, growth rate and recruitment, Journal of Applied Phycology18(3–5), 335–341. ↩︎
  7. To check the data collected by the European Commission, see Commissione Europea (2022). Comunicazione della commissione al parlamento europeo, al consiglio, al comitato economico e sociale europeo e al comitato delle regioni: verso un settore delle alghe forte e sostenibile nell’UE, Bruxelles. ↩︎
  8. On the aforementioned archaeological excavations, see Erlandson J. M., Graham M. H., Bourque B. J., Corbett D., Estes J. A., e Steneck R. S. (2007). The Kelp Highway Hypothesis: Marine Ecology, the Coastal Migration Theory, and the Peopling of the Americas, Journal of Island and Coastal Archaeology/Journal of Island & Coastal Archaeology2(2), 161–174. ↩︎


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