An innovative device called HMS OCToPUS being trialled by conservation scuba divers has shown “promising signs of success”, following years of searching for effective techniques to restore seagrass meadows, says UK charity the Ocean Conservation Trust (OCT).
The OCT focuses on seagrass conservation through its Blue Meadows Programme, aiming to protect existing beds and, in the longer term, restore the many that have been lost in recent decades.
It says it took inspiration for HMS OCToPUS from hydroseeding, a terrestrial planting process designed to spread seeds rapidly. Its own Hydro Marine Seeding (HMS) is a technique whereby seagrass seeds are injected directly into the seabed.
The OCT commissioned Plymouth company Absolute Product Design to engineer a spring-loaded handheld device based on a caulking gun, the latter part of the OCToPUS name deriving from “pressurised underwater seeder”. The gun's 1.5-litre chamber is filled with Zostera marina seeds suspended in a carrying media.
In the course of one 20-minute dive a single diver can use an OCToPUS unit to inject 2,000 seagrass seeds, says the OCT. Its Ocean Habitat Restoration team have now used the guns to seed 1.5 hectares of seabed in the Solent Maritime and two hectares in Plymouth Sound National Marine Park.
While continuing to monitor the restoration sites, they report that preliminary signs of regeneration of the seagrass beds have been positive.
“We focus entirely on subtidal seagrass, and with that there are a variety of additional challenges that come with working below the waves,” said Amelia Newman, OCT seagrass aquaculture technician lead. “So we are really excited to be at this stage with our new device and starting to see how it could revolutionise the way OCT goes about restoring this vitally important habitat.
“We are so grateful for the support of one of our key partners, Ørsted, and the engineers at Absolute Product Design, who have been fundamental in the development of this innovative device.”
“Seagrass meadows are highly efficient carbon-sinks, which improve water quality and provide food and shelter to numerous important species such as sand-eel and herring,” said Samir Whitaker, biodiversity lead specialist for Ørsted, a green energy company. “The UK has lost up to 90% of its seagrass, but groups like the Ocean Conservation Trust have shown that we can bring it back.”
In partnership with Sonardyne, MarineSee, Voyis and Blue Robotics, the OCT says that it has also developed a specialised ROV to further extend its conservation efforts. The vehicle enables it to map seagrass in what it says is unprecedented detail by producing high-resolution photogrammetry to track restoration efforts and monitor established beds.
The ROV's precision will also enable the OCT to better understand seasonal and annual changes in the seagrass meadows, it says.
“We’re very fortunate to spend a lot of time in and on the water but this technology promises a much more accurate, detailed and efficient way we can monitor some of the main metrics of seagrass health,” said OCT conservation projects manager Andy Cameron. “Which also means we can use divers differently for things the ROV can’t do.”
Also on Divernet: ‘I’ve been listening to seagrass meadows’, Seagrass lifts ‘blue carbon’ hopes in Cornwall, Seagrass boost in Cornwall, brainwave in Australia, Be The Champ! – Seagrass Beds
