More people live within 100 kilometers of a coastline than in almost any other climate on Earth. There are more than three times as many folks who spend their lives by the sea than farther away from it, and that proportion is only going to grow along with the global human population. Marine biodiversity is highest near the coast, and per unit of area, the coastline is the most economically productive. Most of the fish that ends up on dinner tables comes from coastal waters, and coastal tides provide a fair amount of energy. Coasts are also playgrounds for people who like to enjoy the ocean, from surfers to sailors to swimmers. Human activities at coastlines can be linked to overfishing, habitat degradation, climate change, harmful algal blooms, hypoxia, and toxic runoff. Taken together, coastal ecosystems are among the most valuable – and vulnerable – on the planet.

As a result, coastal ecosystems need to be carefully monitored so that land managers can make the best, most well informed decisions possible. Along the world’s coastlines, that means they need physical data, like water temperature, current patterns, salinity, and turbidity, along with chemical information like pH or nutrient concentrations, and biological information, like plankton abundance and diversity. Physical data are perhaps the easiest to measure because they can be collected without much human intervention. Unfortunately, it can also become quite expensive. That’s because that data is usually collected by research vessels or by buoys. Not only are those methods expensive, but they also come with some reliability concerns. Tides can affect readings from buoys, for example.

Satellite imaging can alleviate some of those concerns. For one thing, it’s affordable. But satellite images lack the spatial resolution that a research vessel would have, and the need to correct imaging for atmospheric distortion introduces a certain amount of uncertainty into the data. Sensors mounted on aircraft improve upon those problems, but are more costly. In some places, researchers have mounted video camera in fixed positions to watch the sea surface, but they’re obviously immobile and can only view some two kilometers from their permanent locations.

Given those problems, a Plymouth Marine Laboratory researcher named Robert J. W. Brewin, and his colleagues, realized that citizen science could help. Hundreds of thousands of folks already take to coastal waters every day. In the UK alone, some 5.4 million people spend time in contact with the ocean every year, including around 800,000 kayakers, 624,000 sailors, 518,000 surfers, 271,000 scuba divers, and 4.8 million swimmers. If they were equipped with small devices to collect simple information, like sea surface temperature, then researchers would have more useful data than they could ever get from all the buoys, satellites, aircraft, and video cameras combined.

The question is if the data collected from surfers could be both reliable and unobtrusive enough to not interfere with the surfing itself.

An avid surfer, Brewin decided that he would be his own case study. First, he found a lightweight temperature logger that he affixed to his surfboard’s ankle leash with a pair of cable ties. By putting it on the leash, he could ensure that the device stayed out of the way and would always remain submerged. Then, to keep track of his location, he used a small GPS unit housed inside of a waterproof container that he strapped to his waist.

For an entire year, from January 5, 2014 through January 4, 2015, he surfed with the GPS and temperature logger. In all he surfed 85 times; nearly three quarters of his surfing episodes were at the same beach. That gave him almost weekly temperature readings from the same spot on England’s southwestern coastline. To verify the accuracy and reliability of the temperature readings, he compared the data derived from the temperature logger with those from a nearby buoy and with satellite data.

Brewin found that his own data agreed quite nicely with those from the buoy. The sea surface temperature information he collected while surfing captured both the general seasonality of water temperature (lower in the winter; higher in the summer) as well as smaller, abrupt changes, just as the buoy does. However, there were still some differences between the two measurement strategies. The researchers suspect that’s because the buoy is positioned a bit farther away from the coast than surfers tend to stay, and therefore is not in a position to track extremely localized variations in water temperature adjacent to the shoreline due to things like run-off from rainfall.

The GPS data also proved quite informative. Most importantly, the GPS information was linked with the temperature data so that the researchers could localize their sea surface temperature readings. However, Brewin also used his geolocation data to assess his surfing performance. He and his team reasoned that citizen science efforts can be made more successful if an air of competition is involved, essentially turning data collection into a game, much as smartphone apps use their data to assess walking, running, or biking performance, allowing users to compare their performance with others via social media. Over the year, the GPS information revealed that Brewin caught 2012 waves, surfed for 90.6 hours, and covered a distance of 375.8 kilometers of which nearly a third were covered while riding waves. On a scale of 1-10, Brewin’s performance was rated 5-6.

The researchers acknowledge that their system would have to be modified if it was to be implemented more broadly. For example, it took a bit more time to offload the data from both devices after each surfing session than they think most surfers would be willing to spend. However in general they concluded that it is quite “feasible to use surfers as a platform to acquire high-quality data on environmental indicators in the coastal environment.” If they reached a suitable number of surfers, they estimate that some 40 million measurements could be taken every year just in the UK. Even if only one percent of UK surfers participated in their data collection efforts, they could still take in some 400,000 measurements each year, which is far more than is currently being measured by conventional methods.

Even more promising, the researchers point out that surfing is enjoyed worldwide, and often on beaches that are inaccessible to conventional data collection methods because they’re too remote or are located near vulnerable reef environments. And some of the best surfing in the world occurs in countries with little coastal monitoring to begin with, especially in parts of Asia, Africa, and South America.

Surfers are probably more motivated to help assess environmental quality than others as well. After all, they have an intrinsic motivation to protect the ecosystems they rely on for their entertainment. – Jason G. Goldman | 10 July 2015



Source: Brewin RJW, de Mora L, Jackson T, Brewin TG, Shutler J (2015) On the Potential of Surfers to Monitor Environmental Indicators in the Coastal Zone. PLoS ONE 10(7): e0127706. DOI: 10.1371/ journal.pone.0127706.



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