Underlying Barrier in the Atlantic Ocean Separates Odd Deep-Sea Jelly Relatives
In a groundbreaking study published in the online version of Deep Sea Research on July 3, a team of researchers led by Javier Montenegro, a biologist at the University of Western Australia, have discovered an oceanic barrier preventing some deep-sea jellyfish of the subspecies Botrynema brucei ellinorae from reaching the Atlantic Ocean.
The study reveals that this barrier is located within the North Atlantic Drift, a warm ocean current that extends northward from the Gulf Stream. This discovery could help scientists better understand evolutionary relationships and dispersal patterns among marine species.
The subspecies of B. brucei ellinorae jellyfish can be divided into two groups based on whether individual specimens have a knob on their umbrella-like bell structure. Jellyfish with a distinctive knob live across all oceans and latitudes, while those without a knob have only ever been documented in the Arctic and sub-Arctic. The genetic data indicated that specimens of B. brucei ellinorae with and without knobs in the Arctic and sub-Arctic were almost identical to specimens with knobs in the western Atlantic. This suggests that the barrier could keep B. brucei ellinorae jellyfish without a knob confined to the north while allowing those with a knob to travel further south.
Montenegro and his colleagues examined observational and photographic records of B. brucei ellinorae going back more than 120 years. Their research shows that certain Arctic animals, likely including some species of sharks such as the white-spotted smooth-hound shark (white-spotted smooth-hound), might be prevented from spreading into the Atlantic Ocean by this mysterious oceanic barrier.
The differences in the shape of Botrynema brucei ellinorae jellyfish, despite strong genetic similarities, suggest the existence of a deep-sea bio-geographic barrier in the Atlantic Ocean. The study highlights the need to study more about the biodiversity of gelatinous marine animals, particularly those with distinctive shapes within a single genetic lineage.
However, the North Atlantic Drift may not be the only obstacle for knobless B. brucei ellinorae jellyfish. There may be predators lurking beyond it that knobless jellies aren't equipped to escape. Further research is required to fully understand the implications of this discovery and the role of the North Atlantic Drift in shaping marine ecosystems.
