Германы RV Polarstern хөлөг онгоцны судлаачид Антарктидын Уэдделлийн тэнгисийн ёроолоос 60 сая орчим мөсөн загасны үүрийг олж илрүүлсэн нь түүхэн дэх хамгийн том үржлийн колони болж байна.
Alfred Wegener Institute-ийн эрдэмтэд далайн ёроолын экосистемийг судлах явцдаа OFOBS камерын тусламжтайгаар 240 хавтгай дөрвөлжин километр талбайг хамарсан энэхүү өвөрмөц бүсийг санамсаргүйгээр олжээ. Neopagetopsis ionah төрлийн мөсөн загас нь гемоглобингүй цустай гэдгээрээ онцлог бөгөөд судалгааны багийн ажигласнаар үүр бүр нь дунджаар 1,700 өндөгтэй, насанд хүрсэн загаснууд тэдгээрийг хамгаалж байв.
Судлаачдын тогтоосноор, уг бүс нутагт далайн гүнээс оргилон гарч ирэх 2 хэмээр дулаан урсгал нь бичил амьтдыг (зоопланктон) авчирдаг нь загас үржих таатай нөхцөлийг бүрдүүлдэг байна. Энэхүү колони нь маш тодорхой хил заагтайгаараа оцон шувууны сүрэгтэй төстэй бөгөөд үүрүүдийн хооронд үхсэн загасныซาก олдсон нь тухайн экосистем дэх хүнсний гинжин хэлхээний чухал хэсэг болохыг харуулж байна.
Одоогоор эрдэмтэд уг газрыг Далайн хамгаалалттай бүс болгох саналыг Commission for the Conservation of Antarctic Marine Living Resources байгууллагад хүргүүлээд байна. Судалгааны баг тус бүсэд камер байрлуулж, мөсөн загасны үржлийн үйл явц болон орчны өөрчлөлтийг үргэлжлүүлэн хянаж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Scientists have found an estimated 60 million icefish nests on the seafloor of Antarctica’s Weddell Sea, revealing the largest fish breeding colony ever recorded. The discovery happened during an expedition aboard the German icebreaker RV Polarstern, where researchers spotted a huge underwater nursery filled with adult icefish protecting their eggs.
The team was not originally looking for a breeding colony. Scientists from the Alfred Wegener Institute were studying the Weddell Sea ecosystem and using an underwater camera system to explore the seafloor. The Ocean Floor Observation and Bathymetry System (OFOBS), a one-ton camera towed behind the ship, captured the unexpected discovery.
The nests belonged to Neopagetopsis ionah, a species of Antarctic icefish known for its unusual biology. These fish do not have hemoglobin in their blood, making them the only known vertebrates with this feature and giving them a ghostly white appearance.
Millions of Nests Covering the Antarctic Seafloor
The discovery unfolded almost by accident during the expedition. Graduate researcher Lilian Böhringer was watching the live camera feed when she started seeing hundreds of nests across the ocean floor. The camera kept moving over the seabed and the nests continued appearing.
“The camera was moving [across the seafloor] and it just didn’t stop. They were everywhere,” she said.
The size of the breeding area surprised the researchers. Before this discovery, the largest groups of icefish nests ever seen contained only a few dozen sites. The newly found colony stretched across around 240 square kilometers (93 square miles) and included an estimated 60 million nests.
The nests were small bowls dug into the muddy seafloor by the fish. Most of them had an adult icefish nearby, guarding the eggs. Researchers estimated that each nest contained around 1,700 eggs, meaning the colony supports an enormous number of developing fish.
Researcher Autun Purser from the Alfred Wegener Institute said the team quickly understood the importance of the discovery after reviewing the data.
“We realized after ringing up the home institute the next day that we had found something spectacular,” he explained.
The colony also had a surprisingly clear edge. Researchers noticed that the dense area of nests suddenly stopped, almost like a border.
“[The colony] went from very, very dense to nothing, much like penguin colonies,” compared Purser. “It was like a line in the sand.”
A Warm Current Creates the Right Conditions
The researchers had been studying an area where warmer water was rising from deeper parts of the ocean. This upwelling was around 2 degrees Celsius warmer than the surrounding water and was located where the icefish colony was found.
The rising water also brought microscopic zooplankton near the surface. These tiny organisms provide food for young icefish after they hatch, allowing them to feed before returning to deeper waters later in life.
Purser said the presence of icefish in the area made sense because of the available food, but the discovery of such a huge breeding colony was unexpected. The researchers believe the warm water area may help explain why so many icefish gathered there.
As reported in a study published in the journal Current Biology, the team also found many dead icefish between the active nests. These remains suggest the colony is an important part of the local ecosystem and may provide a major food source for Weddell seals.
A Discovery That Could Help Save a Species
The discovery has led to efforts to protect the area through the Commission for the Conservation of Antarctic Marine Living Resources. Scientists are working to have the site considered as a Marine Protected Area.
“The area surveyed harbors the most spatially expansive continuous fish breeding colony discovered to date globally at any depth, as well as an exceptionally high Antarctic seafloor biomass,” stated the study team.
Before leaving the region, the RV Polarstern crew placed two cameras near the colony to continue watching the ecosystem. The goal is to learn more about how the icefish breeding ground changes and how the animals use this unusual environment.
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