Scottish scientist dives into underwater world of marine life around shipwrecks
Project to look at sealife around watery graves
Scots scientists are spearheading a n international project to monitor marine life around shipwrecks, to better understand the impact of changing underwater environments.
An estimated three million sunken wrecks are scattered across the world’s oceans, rivers and lakes and many have been reclaimed by aquatic life.
Tracking species that make their homes in submerged vessels can offer vital clues about how these lifeforms adapt to survive, according to the study team.
Surveillance of wreck sites could aid future efforts to protect species at risk from shifts in the marine ecosystem, the experts say.
The research is also shedding fresh light on connectivity – the ability of a species to move freely from place to place so they can find food and breed.
It is also aiding understanding of the complex process known as succession – how the mix of species and habitats at a given location changes over time.
And insights are being gained into processes such as disturbance, caused by temporary changes in environmental conditions, and degradation brought about by habitat destruction and commercial fishing.
“Wrecked vessels, from large ships to small dinghies, provide artificial structures and materials that are starkly different from the surrounding ecosystem,” said Dr Georgia Holly, a marine archaeologist at Edinburgh University.
“For the first time, scientists from around the world are collaborating to study the impact of these wrecks, some of which go back hundreds, even thousands of years.
“They provide underwater islands where species are surviving and thriving, and larger creatures such as sharks and whales are also believed to use them as navigational spots to travel between.”
The study team has been observing how shipwrecks can harbour valuable ecological resources and become home to a rich variety of organisms.
Microorganisms, algae and invertebrates, such as corals and sponges, grow on submerged debris and materials.
Small fish and crustaceans often find shelter in the crevices of sunken material, while larger fish and predators use shipwrecks as feeding grounds and rest stops as they swim from place to place.
Yet while shipwrecks can become biodiversity hotspots, they can also harbour harmful invasive species or dangerous materials, the team says. These can cause damage to existing habitats in the surrounding area and introduce harmful substances such as oil.
Many of these often-elusive wrecks are classified as Underwater Cultural Heritage by UNESCO.
Academics believe there is an estimated 50,000 scattered around Britain’s coastline, many of which have been lying on the seabed for well over a century.
Records show vessels have been stranded on the rocky coasts, foundered in bad weather, and sunk by enemy action in the two World Wars.
Technical developments in diving equipment over the past 50 years mean that wrecks now as deep as 100 metres are being opened up to the more adventurous underwater explorers.
Dr Holly was part of a team that studied the world’s oldest intact shipwreck – a 75ft Greek merchant ship dating back more than 2,400 years that was found lying on its side off the Black Sea coast of Bulgaria in 2018.
Next month she travels to the Pitcairn Islands in the southern Pacific Ocean to look at the impact of tourism on the people of the remote islands, sparked by the wreck of the famous Royal Navy vessel the HMS Bounty which sank there in 1789 following a mutiny by its crew.
“While shipwrecks are widely recognised for their cultural significance, they are also often important ecological habitats, forming island-like ecosystems important for both biodiversity, and coastal people’s heritage and livelihoods,” Holly said.
“There is so much still to be
discovered but the biggest dangers to these wrecks are climate change, coastal erosion, the presence of treasure hunters and other human behaviours.
“We are in a in a bit of a race against these threats as many of the wreck sites are difficult to police.”
To help develop this emerging discipline, the study team suggests establishing a global biocultural heritage monitoring network for shipwrecks that are ripe for scientific exploration.
Sensitive use of advanced technologies can help ensure that shipwrecks remain protected as both ecological and cultural resources, Dr Holly added.
The research, published in Bioscience journal, was completed by a team of ecologists and archaeologists from the UK and the US.