Fossil Spines Reveal the Deep Sea’s Past

In the ocean’s depths, primitive life likely originated eons ago. Nowadays, the deep sea is renowned for its peculiar and unusual marine life. Researchers are actively investigating how species’ diversity on the ocean floor has evolved over time. Some theories suggest that deep-sea ecosystems have repeatedly developed after multiple mass extinctions and significant shifts in oceanic conditions. Consequently, the current deep-sea life may be relatively recent in the Earth’s history. However, mounting evidence suggests that some areas of this environment are much older than previously assumed.

Göttingen researchers find evidence of deep-sea invertebrates’ stable presence for 104 million years through fossilized sea urchin spines. These findings have been documented in the journal PLOS ONE.

Fossil spines reveal the deep sea’s past: Deep-Sea Fossils Reveal Millennia of Irregular Echinoid Evolution

The scientists analyzed more than 1,400 sediment samples obtained from boreholes situated in the Pacific, Atlantic, and Southern Oceans, representing past water depths ranging from 200 to 4,700 meters. So, they identified over 40,000 fragments of spines, classifying them as irregular echinoids based on their structure and form. To make comparisons, the researchers documented the morphological characteristics of the spines, including their shape and length, and measured the thickness of approximately 170 spines from two distinct time periods. To gauge the total mass of sea urchins in their habitat, known as their biomass, they assessed the quantity of spiny material within the sediments.

Deep-Sea Fossils Uncover Ancient Survival Strategies

Fossilized spines suggest continuous deep-sea habitation by irregular echinoids for 104 million years. Additionally, these spines provide historical insights: the mass extinction event, tied to a meteorite impact 66 million years ago, altered spine morphology, resulting in the “Lilliput Effect,” favoring smaller species after the extinction. Consequently, this could be attributed to a scarcity of food at the deep-sea floor.

The research project also included the University of Heidelberg, the University of Frankfurt, and the Museum für Naturkunde Berlin.

Read the original article on ScienceDaily.

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