When the Royal Society for the Protection of Birds (RSPB) of Great Britain established the marking of binoculars, their goal was to track their behavior and movement along the coast of North Wales. Tag data showed that at night, these seabirds spent free time on the surface of the sea. “We saw this as an opportunity to reuse data and test if the birds can drift with the tidal current,” says Matt Cooper, Master of Oceanography, who graduated from Bangor University in Wales. It turns out that they were, according to a new study under the leadership of Cooper, which shows the potential of using seabirds to measure ocean currents. The results were published today in the journal European Geosciences Union Ocean Science,
Using seabirds to tell us about this can be especially useful for marine renewable energy. The generation of tidal energy requires detailed knowledge of current speeds. Scientists and engineers traditionally measure tides using radar or deploying anchors and buoys with scientific instruments. However, these intelligence methods are complex and expensive. If marked seabirds can provide tidal data over a large area, they can help identify areas that would be good sources of tidal energy.
Cooper's leaders at Bangor University were aware of his interest in tidal energy and data collection, so they suggested that he examine the seabird data collected by the RSPB to see if tidal data could be extracted from it. A few years ago, from 2011 to 2014, aRSPBteam installed GPStags on razors on Puffin Island, North Wales, to study their behavior in distribution and breeding and feeding. These black-and-white seabirds, like dead ends and blue-eyed seabirds, only come ashore to breed. They spend most of their time at sea, feeding or resting on the surface of the ocean.
The data collected when the birds sat on the surface of the sea for several hours in a row was interesting in terms of bird behavior, but researchers from Bangor University saw another potential use. “We took the data that was dropped from the original study and applied it to test the hypothesis in another field of study,” says Cooper. “As far as we know, this article for the first time describes the use of tagged seabirds to measure currents of any type,” the researchers write in Ocean Science study of.
The non-invasive GPS tags on the laces recorded their position every 100 seconds. With a set of positions and a known time between each of them, scientists could calculate the speed and direction of movement of birds. After sunset, the birds rested for a long time on the surface of the sea, falling passively with the passage. "[At these times] their change of position will reflect the movement of water on the surface of the ocean, ”explains Cooper.
At speeds of more than 1 meter per second, the average tidal currents in the Irish Sea region, which the researchers focused on, are very fast, faster than shaving filler, but much slower than the speeds reached by birds during flight. This means that the team can filter the time when the birds fly. In addition, the filtered data showed that when the birds drift, the direction of movement changed during times of low and high tide, when it is expected that the currents in this area changed from low tide to flow and vice versa. Therefore, the team could be sure that they track the speed and direction of sea currents, and not the independent movements of birds.
The use of seabirds to measure tidal currents has its limitations. “We need to remember that these birds behave naturally, and we cannot determine where they go,” says Cooper. But Ocean Science The study shows that there is potential for this low-cost method to provide important tidal information over a wide area. By studying other tagged seabirds, we could learn more about our oceans, especially in more remote areas where it is difficult to collect oceanographic data.
Cooper also hopes that this method can reduce the cost of creating tidal renewable energy, "which has become an obstacle to the development of this much-needed industry."
European Union geoscience, ,