Орчин үеийн дэвшилтэт дүрслэлийн технологи ашиглан хийсэн судалгаагаар 540 сая жилийн настай олдворууд нь амьтны мөр бус, харин бичил биетний үлдэгдэл болохыг тогтоожээ.
Бразилын Мату-Гросу-ду-Сул мужаас олдсон, Эдиакарын галавын үед хамаарах эдгээр бичил олдворыг өмнө нь амьтдын нүүж байсан мөр гэж таамаглаж байв. Энэхүү таамаглал нь амьтны аймаг “Кембрийн тэсрэлт”-ээс өмнө үүссэн байж болзошгүй гэсэн дүгнэлтэд хүргэж байсан юм. Гэвч “Gondwana Research” сэтгүүлд нийтлэгдсэн шинэ судалгаагаар эдгээр бүтцийг микротомограф болон спектроскопийн аргаар дахин шинжилж, өөр дүгнэлтэд хүрчээ.
Харвардын их сургуулийн судлаач Бруно Бекер-Кербер болон түүний баг Бразилын Эрчим хүч, материалын судалгааны төвийн (CNPEM) Sirius бөөмийн хурдасгуурыг ашиглан олдворуудыг нарийн судалсан байна. Шинжилгээгээр эдгээр бүтцэд эсийн хана, эсийн хуваагдал болон органик материалын ул мөр илэрсэн нь тэдгээрийг амьтан бус, харин бактери эсвэл замаг байсныг баталжээ.
Судалгааны багийнхны мэдээлснээр, олдворууд нь гурван өөр хэмжээтэй бүлэгт хуваагдаж байгаа нь тухайн үед эдгээр бичил биетүүд нэгдмэл экосистемд зэрэгцэн оршиж байсныг харуулж байна. Тухайлбал, хамгийн том бүтэц нь замагтай төстэй бол зарим нь хүхэр исэлдүүлэгч бактери байж болзошгүй аж. Ийнхүү 540 сая жилийн өмнөх эдгээр олдвор нь амьтны идэвхтэй үйл ажиллагааны ул мөр бус, харин эртний микробын цэцэглэн хөгжиж байсан орчин болох нь тогтоогдлоо.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Long considered possible evidence of some of the earliest animal activity ever recorded, these tiny fossils discovered in Brazil have sparked renewed debate after being reexamined with powerful modern imaging techniques.
These mysterious structures come from rocks in Mato Grosso do Sul that formed about 540 million years ago during the Ediacaran Period. Earlier studies suggested the markings were burrows made by meiofauna, tiny invertebrates less than a millimeter long.
That interpretation attracted attention because it would have pushed evidence of these animals further back in time, before the Cambrian explosion, when animal life rapidly diversified. A new study published in Gondwana Research revisited the fossils using modern imaging tools and reached a very different conclusion.
Ancient Cells Preserved for Millions of Years
To reexamine the fossils, researchers used microtomography and spectroscopy, techniques that can reveal details invisible under traditional analysis. Lead author Bruno Becker-Kerber said the team found clear signs of cellular structures, along with traces of organic material preserved inside some specimens.
“Using microtomography and spectroscopy techniques, we observed that the microfossils have cellular structures, sometimes with preserved organic material, consistent with bacteria or algae that existed during that period. These aren’t traces of animals that may have passed through the area,” he said.
Much of the work was carried out at the MOGNO beamline of Sirius, the particle accelerator operated by the Brazilian Center for Research in Energy and Materials (CNPEM). There, scientists performed micro- and nanotomography, allowing them to examine structures ranging from a few micrometers down to the nanoscale.
The technology also allowed researchers to zoom in on specific features inside larger rock samples without destroying them. Becker-Kerber also noted that the earlier study proposing an animal origin did not have access to this level of imaging. Researchers also used Raman spectroscopy to identify organic material retained in the fossil structures.
A 540-Million-Year-Old Mystery Got a New Explanation
If the structures had really been burrows, they would have represented evidence that tiny invertebrates were already active on the seafloor during the Ediacaran. The new findings challenge that interpretation. Instead of marks left by moving animals, the fossils contain features expected in preserved microorganisms, , including cell walls, cell divisions, organic remains, and filament-like structures.
The distinction matters because the Ediacaran Period came just before the Cambrian explosion, a time when rising oxygen levels are linked to the emergence and diversification of more complex animal life.
Researchers say the Brazilian fossils no longer support the idea that meiofauna were already present in these environments. Confirmed records of such organisms come from Cambrian rocks, which are younger.
An Ancient Microbial Neighborhood
The team also found that the fossils fall into three distinct size groups, suggesting they may represent different organisms living in the same microbial community. The largest structures resemble green or red algae. Smaller forms could be algae, cyanobacteria, or sulfur-oxidizing bacteria.
Some samples contain pyrite, an iron-sulfur mineral that may be linked to sulfur-oxidizing bacteria. These microorganisms use sulfur as part of their metabolism and can be surprisingly large.
“This group of bacteria is surprising. Some of the largest ever recorded belong precisely to this category,” Becker-Kerber noted. “Unlike the common image we have of microscopic bacteria, certain species can reach diameters larger than a strand of hair and are visible to the naked eye.”
Researchers also identified coiled filaments, concave and convex partitions, and cells containing organic matter.
“This evidence is much closer to bacteria or algae than to mere marks of disturbance caused by animals.”
Rather than documenting early animal activity, the fossils appear to preserve a thriving microbial world that existed hundreds of millions of years ago.
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