Pictures of the week: The Oldest Living Things In The World, by Rachel Sussman

It was while Rachel Sussman was eating Thai food with friends in SoHo, New York, that inspiration struck – an unlikely setting to conceive the idea of shooting the oldest living things in the world. “I was telling them a story about my travels in Japan,” Sussman says. “I’d been in Kyoto, visiting temples that were supposed to be ancient, but they also had a Starbucks around the corner. It just felt uncomfortable.” Friends in Japan told her about a 7,000-year-old tree on the island of Yakushima. A train ride, a ferry boat and a two-day hike later, she found herself standing in front of that tree. Photograph: Rachel Sussman

Over the next two years, she went through a process of “creative churn”, trying to think of a project that combined art, science and philosophy. Telling this tale over that dinner, it all clicked. Photograph: Rachel Sussman

Sussman spent the next 10 years pursuing her project across the world. She began with Google searches – “I had to figure out what I was looking for” – and moved on to contacting the scientists behind research papers on specific organisms. “Nine times out of 10 they were happy to help,” she says. “They were excited that someone outside their field was interested.” Photograph: Rachel Sussman

She also followed rumours, shooting the Posidonia oceanica seagrass in the Balearic Islands (above) before it was proved, with genetic testing, to be about 100,000 years old. “I love the dissonance between this ancient grass beneath the sea and the hungover sunbathers on the Ibiza scene on the shoreline.” Photograph: Rachel Sussman

Sussman wants her project to add to the environmental debate. The 9,550-year-old spruce gran picea (above) is, she says, “a portrait of climate change”: as the plateau upon which it lives has warmed up, the tree has grown taller. Photograph: Rachel Sussman

Asking Sussman to choose her favourite organism is “a bit like asking a parent to choose their favourite child” but she admits llareta (above), more than 2,000 years old, has become something of a poster child for the project, because it “looks like topiary on steroids”. Photograph: Rachel Sussman

A decade spent on this project has not quelled Sussman’s sense of adventure. “I’ve got plenty more I want to photograph. It’s just that access to some of these things requires a submarine,” she says. “So if James Cameron is reading, I’ve got some ideas." Photograph: Rachel Sussman

The Oldest Living Things In The World, by Rachel Sussman, is published by the University of Chicago Press. To order a copy for £31.50, including UK mainland p&p, call 0330 333 6846 or go to theguardian.com/bookshop Photograph: Rachel Sussman