Throughout an extensive deep-sea expedition conducted off the coast of Argentina in the South Atlantic, researchers achieved several remarkable discoveries. Employing the remotely operated underwater vehicle (ROV) SuBastian, which was deployed from the research vessel Falkor, scientists documented what is currently the largest known reef system built by the white, stony coral Bathelia candida. Furthermore, they successfully recorded the presence of approximately three dozen living organisms strongly suspected to be species entirely new to science.
The expedition was headed by Dr. Maria Emilia Bravo from the University of Buenos Aires. High-definition video footage confirmed that the reef structure extends well beyond previously mapped limits and supports a far more diverse collection of life forms. One surveyed section alone measured at least 0.4 square kilometers, an area comparable to the size of Vatican City. The robust calcareous skeleton formed by Bathelia candida provides a solid foundation for numerous marine animals seeking refuge from harsh underwater currents. Experts emphasize that such reefs are considered highly vulnerable ecosystems due to their extremely slow growth rates and almost negligible capacity for post-damage recovery.
Moving further south, the research team identified comparable reef formations situated roughly 600 kilometers from previously charted locations. Significant attention during the voyage was also dedicated to studying so-called cold seeps—underwater zones where chemically rich fluids emanate from the seafloor. The released methane and other compounds sustain microbial communities, which, in turn, form the base of local food webs. Back in 2024, Dr. Bravo’s team had published findings reporting the first confirmed seepage of radioactive materials from such sources in Argentinian waters, alongside describing the mixed diets of nearby fauna. The active seep discovered during this recent mission covered an area of about one square kilometer, presenting new inquiries for scientists regarding potential links between these seeps and neighboring coral reef habitats.
At depths approaching four kilometers, the ROV’s cameras captured footage of a whale carcass resting on the seabed—a first for this geographical area. Such “whale falls” can sustain successive deep-sea communities for decades. Moreover, at a depth of approximately 250 meters, researchers managed to film a giant phantom jellyfish. According to the Monterey Bay Aquarium Research Institute, its tentacles can stretch up to ten meters long. This extremely rare deep-sea jelly, known to science for just over a century, was observed in its natural setting, an event of high rarity. The researchers also noted small fish accompanying the jellyfish bell, utilizing its tentacles as a safe haven from predators.
The dives also yielded sobering findings: discarded plastic nets, bags, and even an antique video cassette were spotted on the bottom, preserved in nearly pristine condition due to the cold temperatures and the slow rate of decay in the deep-sea environment. These observations serve as a stark reminder of the increasing human impact on fragile ecosystems. The scientists pointed out that some hydrocarbon vent areas on the seafloor overlap with regions currently under consideration for industrial exploitation. Detailed documentation of these biological communities, as argued by the authors from the University of Buenos Aires, provides regulatory bodies with strong, scientific evidence to consider when granting permits for commercial activities.
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