Scientists are launching a study into how surfers are affected when exposed to human sewage in the water - by taking swabs from their bottoms.
A team from the University of Exeter is joining forces with environmental campaign group Surfers Against Sewage to carry out the research.
In the first project of its kind, the Beach Bums study wants to recruit 150 surfers and bodyboarders from across the county who are in the water at least three times a month.
The team is also asking each participant to recruit someone who does not surf, to form a control group.
The swabs will be taken from the participants' rectums and will give researchers an insight into the microbes that are colonising surfers' guts.
They hope that, by comparing samples from those who regularly spend time in seawater with those who do not, they will be able to build a clearer picture of how antibiotic resistance in the environment can affect people.
The rise of antibiotic resistant bacteria has been described as one of the greatest health threats facing humans today, according to researchers.
As microbes become immune to existing antibiotics, our ability to treat common infections is rapidly diminishing and a Government review recently called on the global pharmaceutical industry to create a £1.3 billion innovation fund for new antibiotics research.
Anne Leonard, one of the researchers leading the study at the university's medical school, said: "We know that surfers regularly swallow lots more seawater than other beach users – around 170ml per session, which is more than 10 times that of sea swimmers.
"We've already shown that this water may contain antibiotic resistant bacteria but we have no idea how this might affect the microbes that live in our guts, or how it could impact upon health.
"So we're asking healthy adults who surf or bodyboard at least three times a month to take part in a study that will shed much needed light on the effects of marine pollution."
Surfers Against Sewage campaigns director Andy Cummins said: "Whilst water quality has improved dramatically in the last 20 years, coastal waters can still be contaminated by sewage from both animals and humans, introducing billions of potentially harmful bacteria into the ocean environment.
"We want to build a clearer picture of the risks people face when entering the water, so we can ensure our seas are safe for everyone to enjoy.
"June 8 marks World Oceans Day and we're launching the Beach Bums study today because we truly believe that healthy oceans can lead to a healthy planet."