Health & Wellbeing

Bacteria in the ocean can significantly alter your skin microbiome after a short swim

Bacteria in the ocean can significantly alter your skin microbiome after a short swim
After a 10-minute swim, all subjects in a new study displayed significantly altered skin microbiomes for up to 24 hours
After a 10-minute swim, all subjects in a new study displayed significantly altered skin microbiomes for up to 24 hours
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After a 10-minute swim, all subjects in a new study displayed significantly altered skin microbiomes for up to 24 hours
After a 10-minute swim, all subjects in a new study displayed significantly altered skin microbiomes for up to 24 hours

A small but striking study has found that a short swim in the ocean can dramatically alter the composition of a person's skin microbiome for at least 24 hours. It is unclear what the implications of these microbiome changes are but the researchers hypothesize the alterations could leave a person more susceptible to infection.

The new study was inspired by recent research finding people who swim in the ocean have a higher risk of contracting a variety of illnesses and infections. Other work has suggested the large population of microorganisms that live on our skin, often referred to as the skin microbiome, can play a role in our susceptibility to infection.

Marisa Chattman Nielsen, from University of California, Irvine, set out to investigate whether swimming in the ocean can directly alter the composition of our skin microbiome, and if so, for how long? Nine subjects were recruited, and their skin microbiomes were tracked before, immediately after, and 24 hours after, a 10-minute ocean swim.

The results revealed a short ocean swim distinctly altered all the participants' skin microbiomes. Following the swim all nine subjects showed similar bacterial communities on their skin, and very different compositions from what was there pre-swim. The alterations remained for up to 24 hours, although in most subjects the microbiome did consistently return to a pre-swim composition after about a day.

"One very interesting finding was that Vibrio species – only identified to the genus level –were detected on every participant after swimming in the ocean, and air drying," explains Nielsen, lead author on the study. "While many Vibrio are not pathogenic, the fact that we recovered them on the skin after swimming demonstrates that pathogenic Vibrio species could potentially persist on the skin after swimming."

It's important to note that the primary goal of the study was to simply investigate how ocean water can affect the human skin microbiome, and there is no evidence that this microbiome disruption enhances a person's receptivity to infection. This study is also not yet published or peer-reviewed, as the researchers only just presented initial data at the recent annual meeting of the American Society for Microbiology.

It is also reasonable to ask how this exposure to ocean water disrupts the skin microbiome any more significantly than a thorough shower or bath. The implication in the study is that while any water exposure will obviously slightly disrupt the skin microbiome, it is this process, in addition to the major volume of bacterial pathogens present in ocean water, that makes a swim in the sea more potentially harmful.

In the end, this research should not fundamentally scare people off a swim in the ocean. There is a large array of science pointing to an assortment of health benefits that can be garnered from a dip in the sea. However, this is a solid reminder that the ocean is not akin to a sterile salt water bath, but in fact it can be filled with a large volume of different opportunistic and pathogenic microbes.

Source: American Society for Microbiology

It is mind blowing to think about all of the microorganisms in a single drop of water. I checked out my pond water several times under 1500 and 2000 magnification. Too think about the amount that is in that pond or a river or ocean. The human body is incredibly resilient to these microbes.
Bill S.
I grew up on the beach in Southern California and surfed and swam just about everyday for 40 some years. I have been sick twice in my life, both times from the flu. This study just proves the human body is tougher than people give it credit for.
So non peer-reviewed non-published research states the following: That individuals who had differing skin microbiomes previous to an experiment were then placed in a common external environment and came out with similar skin microbiomes. Additionally, the external environment they were exposed to consisted of a fluid environment which would remove the previous microbiomes and then replace them with ones that were in the environment. This is like saying that people who were dirty from a variety of activities (concrete pouring, dirt bike riding, gym work-out, plumbing repair, HVAC install, etc) were then all asked to shower for 15 minutes with the same soap and then their skin showed remarkable similarities in microbiomes. This one may win the award for most obvious research. Of course individuals who were in the ocean (or any other aquatic environment) would come out with the microbiomes they had on their skin removed and the microbiomes present in the aquatic environment present.
As another individual noted, anecdotal evidence from those who spend a lot of time in the ocean would suggest that spending time in the ocean makes one healthier. This article seems to be a "red herring" attempt to draw attention to ocean environmental issues. Not that we don't have concerns- but maybe this isn't an acutal significant event.
"Ocean" means different things in different places.
In a lot of those places, it means "Sewage outfall".
These researchers should work out if there's a correlation between their results and chosen swimming locations proximity to pollution, before broadly blaming "the ocean" here.
They offered the "potential pathogen" speculation, which is reasonable. But, why not also speculate that these organisms could be protective.
It sounds like another study done by people, who needs to find jobs in a new field. Or perhaps it is the author of the press release chose to omit that alternative speculation. It takes a good imagination to be a good scientist, and someone who is willing to look at both sides of the coin.
And did they take these very same people, let these microbiomes normalize without showers for a few days, and then check them before and after a shower, with hair shampoo, antimicrobial soap, and such? If not, why not?