GB Row: A Unique Blend of Science and Adventure

As if being founder of NatureMetrics isn’t adventure enough, last summer our founder Kat Bruce elected to spend a month at sea in a tiny boat with five men, rowing and resting in 2 hour shifts, 24 hours a day… and collecting eDNA samples of course!

She was taking part in GB Row Challenge, a unique event that combines endurance sports with environmental science and ocean conservation.

First launched in 2005, the event sees teams attempt a non-stop unsupported circumnavigation of the 2,000-mile British coastline in high-tech, but ultimately human-powered rowing boats. Crews set off from Tower Bridge in central London in June, heading down the River Thames to the sea, where they turn right to take a clockwise route, first dodging the heavy boat traffic along the South coast and then rounding Land’s End to row up the middle of the Irish sea, through the Hebrides, around the top of Scotland and back down the other side until they get back to the Thames and finish under Tower Bridge as they started. Much more complex than rowing across an ocean, crews have to learn how to work with the winds and tides, employing rapid decision-making to safely navigate challenging coastal waters while making the fastest possible progress. All while sleeping for just two hours at a time and rowing for twelve hours a day.

Events like this represent a fantastic opportunity to gather extensive environmental data that would cost researchers vast amounts of money to launch scientific expeditions for. From 2022-2025, GB Row Challenge has teamed up with the University of Portsmouth to capitalise on this opportunity and create a ground breaking event with true purpose. The 6-person ocean rowing boats used for GB Row Challenge are adapted to integrate equipment for collecting microplastics, underwater sound recordings and eDNA – with some help from the rowers along the way. With the race running annually and multiple crews taking part each time, the dataset built up over the coming four years promises to be one of the most significant contributions to our knowledge of British coastal waters

Adapting the boats presented a significant engineering challenge long before the rowers began their physical one. Constraints included building equipment into very small, awkward spaces, needing to minimise drag and weight and to avoid any risk of interfering with critical onboard equipment (e.g. for navigation, drinking water, safety). The equipment needed to run for at least a month on a battery that would power a hair dryer for about 30 minutes. Sound from the microplastics pump had to be deadened to minimise its interference with the sound recording, and the eDNA couldn’t be added to the same pump system because the plastic components risked contaminating the microplastics dataset. The brilliant engineers at Porvair, Harwin and RS Aqua built a microplastics sampling set-up into one of the hatches that ran automatically for 3 hours a day, and embedded the hydrophone into the boats’ rudders, which recorded underwater sound throughout the day. For 2022, eDNA samples were collected manually by the rowers, but a separate pumping system is now being integrated into the stern of the boats for this year’s challenge.

The 2022 event started on 12th June with three crews taking part.

• All Systems Row: 5 women
• Sealegs: 3 men, 2 women
• Albatross: 5 men, 1 women

Kat was a member of Team Albatross, which also featured triple Olympic gold medallist rower Andy Triggs-Hodge and GB Row founder William de Laszlo. All three crews enjoyed good conditions along the South coast, giving the rowers the chance to settle into the routine and become adept at their various duties, including (for Kat) scientific ones. This involved changing the microplastics filter each afternoon and collecting eDNA samples each morning and evening.

Because of space limitations and a need to keep waste to an absolute minimum, some compromises on our usual standards of sterility for eDNA sampling had to be made. The kits didn’t include gloves to wear while sampling, and the same plastic container was used to scoop water from the sea surface each time. This container was stored in the cabin – a space about the size of a two-man tent where three rowers ate, slept and went about their chores. Decontamination wasn’t possible and Kat managed to sit on her water bucket at least twice, so it was held together with electrical tape by the time the crew made it back to London. We would like to emphasize that this pained us greatly, but we stalwartly viewed it as an opportunity to stress-test the robustness of the approach. We are delighted that the integration of the pump system means future sampling will be very much cleaner. The rowers will be pleased about that too because having to manually pump water for science in between 2-hour rowing shifts is not viewed with much enthusiasm.

By 25th June, all three boats were in the Irish sea. Team Albatross were approaching the top of Ireland, All Systems Row approaching the bottom of it, with Sealegs in the middle. A Force 8 storm (much stronger than predicted) hit the crews and sadly spelled the end of the journey for two of them.

Team Albatross were forced to come to land for a few days before continuing on – the rowing boats are well able to weather big storms at sea, but proximity to land posed a bigger risk. With the row no longer counting as continuous or unsupported – and records off the table – it was now the scientific mission that made the crew absolutely determined to carry on. 34 days after setting off, they made it back to London with their precious cargo of samples and data (and some impressive beards!).

In Kat’s words:

‘it’s hard to describe the beauty and variety of the British coastline, but the West and North of Scotland just blew us away. Making our way up through the Western Isles, travelling past the wildest of landscapes through sunrises and sunsets, and with dolphins, seals and so many seabirds around us it really was the most incredible immersion in nature. The whole expedition brought home to us how rich our coastal seas are and how vital it is to protect them. We could appreciate some of the threats as well – all the shipping traffic we had to navigate is a hazard for wildlife too, and we saw evidence of bird flu with dead seabirds floating on the water’s surface as we came down the East coast. At the same time we know our rivers are pumping out pollution, many habitats have been damaged by trawling, and climate change threatens major disruption to our ocean systems. We must act decisively to protect this incredible natural wealth in our marine environment, and luckily there are so many brilliant projects and initiatives working hard to do just that. Hopefully the data we collected can help amplify and accelerate that work.’

Speaking of the data, this week sees the release of the first preliminary scientific report from the University of Portsmouth. University researchers have been analysing the microplastics samples and sound recordings, while we analysed the eDNA samples from all three boats at NatureMetrics.

You can read the full report here, but to briefly summarise:

Much greater concentrations of microplastics were recorded than have been reported in other studies. This is likely to be due to the use of finer filters than those used in previous studies, so smaller fragments were picked up. Highest concentrations were recorded in the Thames estuary and the Irish Sea, while areas like the North-West of Scotland were virtually free from microplastics.

Initial analysis of the sound data recorded by the hydrophones identified both noise pollution from sources such as shipping, and some groups of marine wildlife, including cetaceans (whales and dolphins) and snapping shrimps. It isn’t possible to far to make identification to species level but there remains a lot to be discovered in this data, which will be worked on by PhD students over the coming years.

eDNA samples were analysed for vertebrate DNA to identify fish, birds and marine mammals. Even with the fact that the samples were stored at ambient temperature during a heatwave, the dataset still allowed us to start mapping the distribution of over 80 vertebrate species of which more than three-quarters were identified to species level.

• Most of the vertebrate diversity detected was fish, ranging from commercial fisheries species like cod, mackerel and anchovies to those belonging to groups such as gobies, wrasses and clingfish. Undulated rays and conger eels were among some of the most exciting finds, while the most important included several species of sand eels, which are a keystone species in the North Sea, providing a major source of food for colonies of seabirds on the East coast.
• Different patterns of distribution around the coastline can start to be seen, as in the example below for the Clupeidae family (herring, sprat and pilchard). Pilchards were detected only around the southern part of England and Wales, while herring and sprat were recorded right up to the North coast of Scotland.

• Apart from fish, the dataset also contained dolphins and porpoises, grey seals, and several seabird species including puffins, gannets and razorbills that form vast colonies in the cliffs around Scotland and North-East England.

To understand nature, the puzzle must be complete

Ultimately, the real strength of a project like this will be in combining the insights from all the different types of data collected on the boats, in addition to other available data on coastal habitats (e.g. depth, substrate, habitat, protected areas etc) to understand how different factors affect marine biodiversity. Over the coming years all these datasets will be expanded, and PhD students will carry out much more in-depth analyses

“Marine biodiversity isn’t just a nice-to-have,” says Kat. “It’s intrinsic to the functioning of our ocean systems and their ability to reliably deliver the services we value, including commercial fisheries, and carbon sequestration. It’s also vital for maintaining a strong tourism industry. Governments have now committed to reversing the loss of nature within the next decade. If meaningful positive change is to be achieved we have to know the baseline state of biodiversity today so that the outcomes of new policies and conservation interventions can be demonstrated. GB Row Challenge is one of the best opportunities we have to do this.”

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