Bringing the Ocean to Society
17 Apr 2020
How surfers are turning into citizen scientists
Surfboards are being equipped with tiny sensors to monitor seawater temperature.

As reported by MagicSeaWeed, the coastal water temperature is something that has an impact on surfers every day. But it also affects the coastal ecosystem; the carbon and nutrient cycles, the prime production, and the lives of the fish, mammals, plants and algae that live in coastal waters. The water temperature is controlled by things like coastal upwelling and climatic cycles such as El Niño, and is both a cause and an effect of climate change.

Therefore, getting good measurements of the water temperature along the coastlines of the world is really important. Real-time measurements are not as straightforward to obtain as you might think. Remote sensing measurements using satellites can cover vast areas, but they are not as accurate as they could be. In-situ measurements using buoys and ships are highly accurate, but they can’t cover such large areas.

So there is still a need to fill the gap with as many more measurements as possible. Scientists are continually coming up with ways of doing this. One method is tagging coastal mammals with miniature sensors, and letting them do the data collecting for us.

Of course, there is one species of coastal mammal that is ideal for this purpose; surfers. Every day of the year, when not in lockdown, surfers are immersed in coastal waters all over the world, so it would be a no-brainer to get us to carry tiny sensors, as long as they don’t interfere with our surfing. Moreover, we have a vested interest in the water temperature because it affects them directly.

In fact, a really interesting experiment has been done recently, comparing two methods of surfer-driven data collection. Between July 2017 and July 2018, data was logged using both methods during 148 surf sessions in the southwest UK and in Southern California. You can download the original paper here.

The first method used commercially available temperature sensors attached to the surfers’ leashes. The second method used some specially modified fins. You might have heard of them – they are called Smartfins and are being developed as a collaboration between the Surfrider Foundation and Scripps Institute of Oceanography.

The Smartfin is a similar size and weight to a normal fin, but contains sensors that record temperature, motion, and geo-location. In the future, the designers plan to integrate biological and chemical sensors as well.

With the leash-mounted sensors, this varied between about 1 cm and 1.5 m; whereas with the Smartfin it varied between about 5 and 50 cm, depending on the type of board. Also, the leash sensors were more exposed to sunlight than the fins were, which meant falsely-high temperature readings that had to be compensated for. It turned out that both methods were very accurate, which means that the general idea of making measurements this way works well.

The results also highlighted a couple of important issues. For example, the distance below the sea surface at which the temperature is sampled is really important.

In general, the technique has great potential for the future. In fact, Smartfin data collection is already ongoing, with hundreds of data points being collected around the world. To improve things further, the sensors need to be made more easily accessible to surfing communities, and surfers need to be more motivated to use them.

Perhaps adding some software to log your surf session and calculate performance statistics might encourage more surfers to them.

Lastly, all this is a great example of citizen science – using large numbers of people to collect and analyse data in a sort of remote, global collaboration. It symbolises cooperation instead of competition, and proves how great things can be achieved – not just in science, but in many aspects of life – by a large number of people each contributing a small amount of effort.