Zodiac cruising is one of the best activities you can do on a South Georgia cruise. Each trip is a shoreline safari, where you can be surrounded by rafts of penguins coming and going from the water, immense elephant seals lying in the surf like deflated bouncy castles and more fur seals claiming their spot on the beach than you can imagine. It’s not uncommon for the wildlife to be so dense that it’s simply impossible to land, making a zodiac cruise the only available option.
But what if you were to take a zodiac cruise in South Georgia and really slow things to look at it from a new perspective? And collect important scientific data at the same time? That’s what I did when I took part in the South Georgia Big Seaweed Survey.
Citizen science in South Georgia
I was sailing on Seaventure, an expedition cruise ship with a strong offering of citizen science projects for its passengers to get involved in. While most of these are centred on the Antarctic Peninsula, like collecting plankton samples for the FjordPhyto project, or carrying out seabird surveys or cloud observations while at sea, joining Swoop’s South Georgia, Antarctica and Falklands Explorer gave me the opportunity to try something entirely new.
But why look at seaweed? At first glance, travelling all the way to a remote island famed for its enormously noisy and colourful king penguin colonies and to spend time looking past the birds to the plants growing on the coast could seem a little quixotic. But as with all citizen science projects, changing the focus of your gaze promised to shed light on wider issues affecting its ecosystem.
Seaweed certainly isn’t glamorous, but it can tell us important things about the health of a marine ecosystem. South Georgia is facing impacts from climate change that we don’t understand yet, from ocean warming and acidification to the spread of non-native species. But it’s such a remote place that scientists just don’t have the base data yet to look at the bigger picture.
This is where the Big Seaweed Survey comes in, run by the Natural History Museum in London in conjunction with the Government of South Georgia & the South Sandwich Islands. And we were promised that we’d still see all the penguins we could ever wish for.
The first seaweed survey
I took part in one of the first surveys with Annette, Seaventure’s citizen science coordinator and one of co-founders of the Polar Citizen Science Collective. The procedure was pretty simple. When our visit to a location coincided with low tide, while everyone else headed out for a zodiac cruise or to attempt a landing, we’d tour the shoreline making recordings.
It felt like having our own private zodiac cruise, getting close to bull fur seals sitting imperiously on the rocks and then scanning the waterline and comparing what we could see to the laminated identification card that laid out all the different types of seaweed.
At some locations there would be enormous ropes of bull skelp swaying with the tide, while in other places I was soon able to quickly pick out Antarctic turf foot from bladder weeds and palm weeds. We took photos of calcified crusts in rock pools and noted bands of bleaching above the high tide mark – the possible signs of warming waters. It was all strangely compelling, and I searched for seaweed as intensely as I’d looked for whale spouts on the crossing to South Georgia.
At each location, we carefully recorded what we’d seen along with a GPS reading and reference photos so that the researchers back at the Natural History Museum could check what we’d collected. And then, with our data neatly collected for the seaweed of Fortuna Bay, we turned our zodiac around and went to see the penguins.
The next day we went out again at Elsehul, a bay almost completely surrounded by cliffs, where we constantly shifted our gaze from the albatrosses nesting in colonies above us to the kelp and weed on the waterline.
It’s something of a cliche to say that a trip to South Georgia makes you feel as if you’re in the middle of a David Attenborough wildlife documentary. But taking part in the survey was the first time I felt like I was in the segment at the end of the film where they go behind the scenes with the camera crew and scientists to show how they made it.
Seaweed survey results
Back at home, I was eager to find out what had happened to the data I helped collect. I reached out to Professor Juliet Brody and Dr Ron Mrowicki, the research leads for the project at the museum, to get some more insight.
In 2021, they carried out survey work in South Georgia and recorded the first instances of a non-native seaweed on the island, after collecting samples of sea lettuce in Grytviken. By comparing it to samples in the museum collection collected before the First World War, it’s thought that this species was accidentally introduced by whaling ships – just as rats and mice had been brought to the island. The data collected by citizen scientists would help the museum build a bigger picture of the island’s ecology.
Mrowicki shared a map showing all the data that had been collected that season. ‘With the more coastal surveys where people are recording different key species of seaweeds on the shore, these produced 39 new records of these different species along the entire north coast of South Georgia, which was big improvements to the data that we had already,’ he said.
In addition, there had been a raft watch, photographing seaweed rafts at sea between South Georgia, the Falklands and Antarctica, which had generated over 150 data points.
All the photos taken by participants in the project – including my own snaps – are now archived at the Natural History Museum. ‘The photographs have been amazing,’ Mrowicki said. ‘They allow us as scientific experts to validate people’s observations of seaweeds, which are very tricky to identify – even for us. They’re also an important record in themselves, having photos from South Georgia where not many people have the chance to go and observe. As well as the data that people record on their forms, having the photos gives us an important baseline to monitor change over time.’
Building up that baseline of data is exactly where citizen science has the power to have a big effect. ‘We’ll be able to start looking more closely at trends over time, in terms of seaweed diversity and distribution of species, the numbers of rafts at different times throughout the season, or in different years,’ he said. ‘The more data that we build up over time from the project, the more insights we will be able to get.’
The big (seaweed) picture
South Georgia remains one of the most incredible places I’ve ever visited. The scale of its wildlife is staggering. Like many others, I was drawn there by the king penguins, the fur seals and the albatrosses – and they didn’t disappoint. But taking part in a project like this made me appreciate them even more, as being on the outermost arms of a complicated ecological web, where every species plays its own role, even if it’s not always well understood.
Being able to contribute to building a picture of the island’s baseline biodiversity felt like a great extra to add on to my trip, especially at a time when we know that ecosystems like South Georgia’s are facing extreme challenges. So if you find yourself down in the Subantarctic, don’t skip the penguins and the seals but do spare a thought for the seaweed as well.
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