Scientists finally uncovered the source of the enigmatic underwater sound known as the bloop, recorded in the remote South Pacific in 1997
In 1997, a mysterious and incredibly loud underwater sound, dubbed the Bloop, captivated the scientific community. Recorded by the National Oceanic and Atmospheric Administration’s (NOAA) underwater microphones, the ultra-low frequency noise was detected across a vast distance, over 5,000 kilometres apart, with its origin traced to a remote point in the South Pacific Ocean near the southern tip of South America.
For years, the source of the Bloop remained a puzzle, with various theories proposed, including the possibility of an unknown deep-sea creature or geological events. Dr. Christopher Fox, leading a team of NOAA oceanographers, initially considered the involvement of large marine animals such as blue whales but eventually turned his attention to geological explanations.
Further investigation and comparison of the Bloop’s recording with sounds of ice calving, or breaking off from glaciers, led researchers to a breakthrough. NOAA and Oregon State University seismologist Robert Dziak proposed that the sound was likely caused by an icequake—a seismic event involving the cracking and breaking of ice.
Supporting this theory, Dziak pointed out the similarities between the Bloop’s characteristics and those of icequake signals recorded off Antarctica. The southern ocean’s natural soundscape is dominated by the noises of ice breaking and cracking, with tens of thousands of icequakes occurring each year as sea ice melts and glaciers calve.
By 2005, scientists had gathered enough evidence to confirm that the Bloop was indeed the result of an icequake, specifically an iceberg cracking and separating from an Antarctic glacier. This conclusion put to rest the more fantastical theories and highlighted the dynamic and often surprising nature of Earth’s cryosphere.
The resolution of the Bloop mystery underscores the importance of continued monitoring and research in understanding the complex interactions between the ocean and the polar ice
