What is Underwater Cultural Heritage? 

UNESCO defines underwater cultural heritage (UCH) as all traces of human existence of a cultural, historical or archaeological nature which, for at least 100 years, have been submerged under water in the ocean, lakes or rivers. This definition covers a range of cultural heritage, but UCH is so much more than a definition and one field of work. 

The stories of our societies and ancestors are wrapped in an intangible connection with the ocean,  preserved on the seafloor as artifacts, shipwrecks, and remains of those lost or buried at sea. Marine global heritage has largely been based on natural features, and the inextricable link between natural and cultural has been ignored. However, UCH functions in a shared natural and cultural heritage space: Ocean Heritage. 

In the follow-up to his seminal work The Unnatural History of the Sea, conservationist Callum Roberts writes in The Ocean of Life that:

‘Impacts [on the ocean] are discussed in isolation at different meetings and by different people, who never quite see the overall picture.’

– Callum roberts, THE OCEAN OF LIFE

He refers to different people within the marine scientific fields, but his point holds true with a group many do not consider: Ocean Heritage professionals. Underwater cultural heritage is an integral part of both cultural heritage and natural heritage, thus making it a shared Ocean Heritage.

A diver explores an underwater shipwreck, with lots of colorful fish around.
Amagisan Maru. Photo credit: Major Projects Foundation, https://majorprojects.org.au/

Underwater Cultural Heritage Spans Disciplines

UCH can take many forms and fits into a variety of other marine science disciplines. From underwater archaeology to anthropology and coastal communities, UCH encompasses it all. On most archaeological excavations, community archaeology and capacity building are a massive component. Additionally, looking towards past relationships with the ocean can help pave the way for a more sustainable future and is a big part of ocean literacy and human understanding of the world around us. Looking to the past is more than just archaeological fieldwork – it can include anything from research in archives to oral history projects. The output of these projects can range from museum exhibitions to magazines, digital platforms, and more. UCH studies allow us to look at voices not traditionally represented, such as women’s or Indigenous peoples’.

UCH and The Ocean Foundation (TOF)

Blue Resilience Initiative: TOF’s Blue Resilience Initiative (BRI) works with communities to strengthen their response to climate change. 

Ocean Science Equity Initiative: TOF’s Ocean Science Equity Initiative works to ensure all countries and communities can monitor and respond to changing ocean conditions.

Plastics Initiative: TOF’s Plastics Initiative works to protect human and environmental health and advance environmental justice priorities in plastics policy.

Teach for the Ocean Initiative: TOF’s Teach For the Ocean Initiative supports a community of marine educators as they work together to advance their approach to teaching and deliver sustained conservation behavior change.

Protecting Underwater Cultural Heritage

UCH protection goes hand-in-hand with many conservation goals shared by marine scientists worldwide. UCH supports ecological marine biodiversity and helps boost sea connectivity. New research indicates that it is beneficial for sites with high UCH and high natural heritage to co-occur and be conserved strategically together. A 2022 paper by Kirstin S. Meyer-Kaiser and Calvin H. Mires coined the term ‘Maritime Heritage Ecology,’ an emerging idea that recognizes the intersection of natural, cultural, historical, and environmental heritage. 

Shipwrecks can function as artificial reefs and provide crucial habitats. They serve as shelters for juvenile species, add hard materials to an otherwise soft seafloor, and can be as indispensable to the seafloor ecology as a natural coral reef or seamount. Waters around protected wrecks have been documented to produce higher fish populations and biomass than in areas of high trawling with no structures on the seafloor. Through this process of ‘spillover’, protected shipwrecks can help increase the strength of surrounding fish stocks. Shipwrecks should not be viewed solely in a culturally significant context – they are part of the natural ocean landscape as well as our Ocean Heritage. 

UCH is also not just the physical remains of the past. Intangible heritage is a large component of the field, as discussed in our work on deep seabed mining and UCH. Watch this conversation with UCH experts on Instagram.

Threats to Ocean Heritage

UCH is under threat from a range of human activities. Bottom trawling threatens UCH as the sea floor gets plowed daily by trawlers, destroying both cultural and natural heritage. There are also future challenges facing UCH.  Deep seabed mining operations, like seafloor drilling, interact with tangible UCH and will destroy heritage by removing it from the seafloor and processing it through a machine before discharge.

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There will also be a negative impact on the intangible cultural heritage in the area. Additional threats to heritage, both natural and cultural,  can come from the material itself, in the form of potentially polluting wrecks (PPWs). While the wrecks from the world wars are part of our cultural heritage, they pose a significant pollution threat to the marine environment, as to fishing and other livelihoods that depend on a healthy ocean.

New Books Released

TOF and Lloyd’s Register Foundation have a UN Decade for Ocean Science-endorsed project to study some of these threats and provide more information on them for the public. Threats to our Ocean Heritage aim to broaden ocean literacy on complex topics across a wide range of stakeholders. Two peer-reviewed books are now available fully open access: Threats to our Ocean Heritage: Bottom Trawling and Threats to Our Ocean Heritage: Potentially Polluting Wrecks. A final book on DSM is being developed as part of the project and will be out in the next year. Stay tuned for updates!