Antarctica is a land of mysteries and profound beauty. The unfathomable depths of this frozen continent are filled with sounds that are reminiscent of spaceships
, along with a variety of other impressive
hums and drones. These are the sounds used to study the diverse marine life that calls this icy wilderness home, according to Colombian scientist Andrea Bonilla, who recently embarked on an expedition to the farthest reaches of Antarctica.
As a biologist from Cornell University in New York, Bonilla took a submersible hydrophone, encased in titanium and attached to a buoy, and submerged it in the midst of the vast ocean that is surrounded by ice floes. The location chosen was the archipelago of the South Shetland Islands.
This hydrophone – a device designed to pick up sound waves underwater – will enable Andrea to explore and understand the behavior patterns of marine mammals, and track their movements across the area during the harsh southern winter. During this time, Antarctica transforms into a place that is nearly uninhabitable. This device functions similarly to a camera trap but serves an auditory purpose and is specifically designed for an aquatic environment.
“The species found here produce sounds that are truly remarkable, akin to something you might hear in a science fiction film like Star Wars, similar to spaceships. Not many ears are fortunate enough to experience these species,” the 32-year-old scientist shared with AFP while on board the ship ARC Simón Bolívar, belonging to the Colombian Navy.
Bonilla, who is currently pursuing a PhD in marine acoustics, along with fellow scientists from Colombia’s 10th Antarctic expedition, have a two-fold mission. They are not only tasked with retrieving hydrophones that were left behind by a Turkish mission last year for further analysis, but also with submerging new devices.
The research they conduct also serves as a gauge of the impact human activity, environmental pollution, and other threats pose to these mammals. This remains a concern despite these creatures inhabiting one of the most well-preserved regions on Earth.
During the expedition, a colony of penguins could be seen sauntering across a massive block of ice shaped like a slide. Close by, the team of researchers observed a humpback whale breaching the surface of the water for a gulp of air, before retreating towards the warmer waters of the Pacific Ocean in a bid to escape the imminent winter.
Bonilla shared a poignant memory – My first encounter with a whale was one that sang and I think that changed my life.
After gorging themselves in the Antarctic Peninsula and Strait of Magellan in Chile for months, thousands of these colossal cetaceans set off on a long voyage to the balmy waters of the tropics. Between June and October, they breed along a marine corridor that stretches from the south of Costa Rica to the north of Peru.
But, as the scientist explains, there are species that are only found here
. For instance, the Weddell and leopard seals emit high-pitched songs of differing tones. These harmonious compositions provide valuable insights into their behaviors.
According to Bonilla, In a marine environment, sound is of paramount importance
. Noise pollution or disturbances in hearing can interfere with the communication of species, or even hinder the normal progression of natural activities such as hunting, she adds.
Throughout the course of the expedition, the scientists installed a total of three microphones. Two were placed in Bransfield Strait and one in Drake Passage.
Using predefined coordinates as a guide, the team traced the path of the buoy that Bonilla had left in the sea a year ago.
When they came within approximately a 300-meter radius of the pinpointed location, Bonilla was able to start remotely signaling the hydrophone in order to locate it using a command box. Once submerged at roughly 500 meters, the device responds to the signals transmitted by Bonilla, followed by the command to detach itself from the anchor and resurface.
Upon witnessing this impressive feat, Bonilla’s colleagues responded with enthusiastic pats on the back, recognizing the scientific value of what had just been accomplished.
Bonilla expressed her excitement, saying, Super thrilled because it was the first time we performed this maneuver in these waters (…) Everything went exceedingly well,
after successfully completing the procedure, which took eight minutes.
Once back on dry land, the Colombian scientist will meticulously analyze a year’s worth of recordings, which have miraculously survived countless risks such as device loss or technical issues.
This research also serves a secondary purpose, which is to support the proposal
that has been promoted by Chile and Argentina since 2012 to designate the Antarctic Peninsula as a protected marine area
.
Bonilla works with spectrograms, which are visual representations of sound frequencies. Her findings will not only be utilized for monitoring marine mammals, but will also contribute to geophysical research.
The microphones are capable of capturing low frequencies such as earthquakes and melting ice, up to medium and high ranges that record animals of different sizes.
For the final phase of the mission, Bonilla attached a new hydrophone to a buoy adorned with a red flag, which will allow her to identify it in the future. After making the final adjustments, she cast it into the water, where it will remain until her return next year.
