Scientists from Göttingen University have made a groundbreaking discovery about the deep-sea ecosystem. According to a recent study published in the journal PLOS ONE, they have found fossil evidence of higher invertebrates, specifically irregular echinoids or sea urchins, colonizing the deep sea for at least 104 million years since the Cretaceous period.
The research team analyzed over 40,000 spine fragments from sediment samples, providing insights into the evolutionary changes of sea urchins over time, particularly after major extinction events. The findings also shed light on the potential impacts of future global warming on deep-sea ecosystems.
The deep sea has always been a mysterious realm, believed to have harbored the earliest life forms on Earth. The species diversity in this environment has been subject to various hypotheses, suggesting that it has undergone repeated rebirth following mass extinctions and marine disturbances. However, the recent study challenges this assumption.
The team from Göttingen University has presented the first fossil evidence of deep-sea colonization by higher invertebrates, specifically irregular echinoids, stretching back 104 million years. Through the analysis of fossil spines, they have revealed the long-standing existence and evolution of sea urchins in the deep sea floor.
To gather these findings, the researchers examined over 1,400 sediment samples from different depths in the Pacific, Atlantic, and Southern Oceans. More than 40,000 spine fragments were discovered, which were identified as belonging to irregular echinoids based on their structure and shape.
By comparing the morphological characteristics of the spines from different time periods, the scientists observed notable changes in shape, length, and thickness. Particularly intriguing was the Lilliput Effect, seen after the devastating meteorite impact at the end of the Cretaceous period, which caused a worldwide mass extinction. The spines became thinner and less diverse in shape, suggesting that smaller species had a survival advantage in the deep sea. The researchers hypothesized that the lack of food at the bottom of the deep sea may have contributed to this phenomenon.
Dr. Frank Wiese, the lead author of the study, emphasized the constant evolution and emergence of new species in the deep sea based on these findings. He also highlighted the relationship between the biomass of sea urchins in the deep sea and water temperature. A spike in sea urchin biomass occurred around 70 million years ago when the water cooled down. This correlation raises concerns about the potential impact of human-induced global warming on the deep-sea ecosystem.
The research project involved collaboration between Göttingen University, Heidelberg University, Frankfurt University, and the Museum für Naturkunde Berlin.
This study adds significant knowledge to our understanding of the deep sea and the ancient history of its inhabitants. It also serves as a reminder of the delicate balance of these ecosystems and the potential threats they face from human activities.