In the freezing depths of the Atlantic Ocean, over a thousand meters from the surface, there is an invisible and impenetrable barrier, at least for some jellyfish of the species Botrynema Brucei Ellinorae. This is what emerges from a study by the University of Western Australia, which has mapped the distribution of these animals in waters all over the globe, identifying a line of demarcation along the 47th North parallel, beyond which only the specimens with a specific morphological characteristic are ventured. A small ethological mystery, of which for now it is not possible to explain the cause.
Botrynema Brucei Ellinorae It is a subspecies of jellyfish that includes specimens with two very different forms: some present a characteristic knob -shaped protuberance on the upper part of the bell, others do not. “Both types are found in arctic and subartic regions-explains Javier Montenegro, the marine biologist who guided the research-but the specimens without protuberance have never been signed south of the North-Atlantic current region, which extends from large benches off the past of Terranova east, to north-western Europe”.
This is, therefore, the impenetrable demarcation line that holds the jellyfish without protuberance in arctic waters, instead allowing others to spread to all latitudes. To find out, the authors of the study studied hundreds of specimens collected by research ships and remote controlled submarine vehicles, and have integrated their observations by studying multiple photographic archives and similar analyzes made in the past.
The line traced by the North-Atlantic current is similar to other geographical boundaries without physical barriers that delimit the distribution of animal species in different regions of the globe. A classic example is the so -called Wallace line, which separates Asian ecosystems from Oceania on the islands south of the Borneo. To make the case of jellyfish in some way Botrynema Brucei Ellinorae However, it is the fact that the line that runs along the 47th north parallel separates two populations belonging to the same species, and is located in the open sea. For this reason, it is difficult to imagine what prevents some specimens, but not to others, to spread in the southern waters.
Impossible, for example, to call into question temperatures or other environmental characteristics, given that animals belong to the same subspecies and should therefore have identical adaptability characteristics. Montenegro, however, advances an intriguing hypothesis: “The pommel – reasoning – could confer a selective advantage against predators outside the arctic and subartic regions”.
For now, it is impossible to confirm the hypotheses of Montenegro, and the mystery of the Botrynema Brucei Ellinorae It is therefore destined to remain such. However, the discovery reminds us how little we know about the ocean abysses, distant and aliens environments that we have started to explore only in recent decades. And it suggests the possibility that other similar barriers scattered throughout the globe exist, invisible borders that shape the distribution of marine life in ways that we still do not fully understand.
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