Since 1973, tenacious sailors have competed in the Volvo Ocean Race, which is often described as the longest and toughest professional sporting event in the world. The nine-month journey crosses 45,000 nautical miles and consists of 11 segments that touch six of the world’s continents and 12 different host cities.
This year’s race began in Alicante, Spain in October 2017. The seven teams competing on the journey have collected valuable scientific data along the way, measuring microplastic particle pollution and other meteorological and oceanographic data in some of the world’s most remote stretches of the high seas.
One of the race boats, named “Turn the Tide on Plastic”, carried a special instrument equipped with filters that captured and measured microplastic particles from samples of ocean water. Meanwhile, the other six race vessels deployed 28 drifter buoys from NOAA at different points along the sailing route to collect data on sea surface temperatures and other oceanographic measurements. These buoys, which are about the size of a large beach ball, contain a sea anchor extending up to 15 meters beneath the ocean surface. NOAA's Global Drifter Lab and Ocean Observing and Monitoring Division coordinated to get the drifters sent to the sailors in order for them to be deployed.
Turning the tide on plastic
Small particles and fragments of plastic are plentiful across the world’s oceans and often come from plastic bottles, bags, and other land-based pollution flowing down rivers and bays that get caught in the global ocean circulation. Though microplastics are extremely tiny - sometimes invisible to the naked eye - they can take thousands of years to degrade, making them harmful to marine life. Fish and other marine organisms easily ingest these small particles, some of which contain chemical additives that ultimately end up in the human food chain. The data collected during the Volvo Ocean Race is helping scientists learn more about the prevalence of microplastics as well as their movement through the world’s oceans.
So far, the highest concentrations of these small plastic particles (360 particles per cubic meter) were found during Leg 6 of the race in the South China Sea - between Hong Kong and the northern Philippines. This region feeds into the North Pacific Ocean Gyre, where large amounts of plastic and other debris are caught in the wider circulation of the Pacific Ocean. High concentrations of microplastics were also found where the Mediterranean Sea meets the Atlantic Ocean (307 particles per cubic meter), one of busiest shipping lanes in the world.
More than just microplastics
While microplastics are a key focus of this year’s ocean race, the expedition has also been a valuable opportunity to collect other useful meteorological and oceanographic measurements. Data such as sea surface temperatures, sea surface salinity, chlorophyll concentrations, and carbon dioxide concentrations (partial pressure of CO2) will help scientists learn more about Earth’s climate. About one-third of human CO2 emissions are absorbed by the oceans, making accurate measurements a key component to understanding the exchange of carbon between Earth’s oceans and atmosphere.
Working with data producers at the Helmholtz Centre for Ocean Research, NOAA scientists are archiving and uploading the ocean data to the NOAA NCEI Global Thermosalinograph Database, where they are available to the public in a standardized, searchable format. This database, which will also include the new microplastic measurements, aims to provide well-organized, quality-controlled datasets on the world’s oceans.
The value of on-site measurements
With oceans covering more than 70 percent of Earth’s surface, data from the oceans is critical to our understanding of Earth’s climate and marine ecosystems. While Earth-orbiting satellites provide remotely sensed data that teach us about sea surface temperatures, ocean currents, and coral bleaching events, on-site (‘in situ’) measurements are just as important due to their high spatial resolution. By taking readings directly in the water at high frequency, scientists can map out ocean features in mere meters, rather than large blocks of kilometers seen from other data sources like satellites.
Scientists can also calibrate ocean data measured by satellites and cross-check it with direct in-water measurements. This ensures that remotely sensed ocean data from satellites is as accurate as possible.
Furthermore, while satellite data is extremely useful, there are limits to what we can measure from space. The newly archived microplastic data, for example, is only available through direct surface measurements from ships and buoys.
The Volvo Ocean Race is now entering the home stretch. While scientists will continue to study this newly collected ocean data for years to come, researchers have already gained valuable insights into the prevalence of microplastic pollution around the world. Scientists at NOAA NCEI hope that this first-year support of the Volvo Ocean Race will begin a long collaboration in future ocean research.