What are Magentofossils?

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What are Magentofossils? Blog Image


In the depths of the Bay of Bengal, scientists have discovered a 50,000-year-old sediment — a giant magnetofossil and one of the youngest to be found yet.

About Magentofossils

  • These are the fossilised remains of magnetic particles created by magnetotactic bacteria, also known as magnetobacteria, and found preserved within the geological records.
  • What are Magnetotactic bacteria?
    • These are mostly prokaryotic organisms that arrange themselves along the earth’s magnetic field.
    • These organisms were believed to follow the magnetic field to reach places that had optimal oxygen concentration.
    • These bacteria contained “novel structured particles, rich in iron” in small sacs that essentially worked as a compass.
    • These magnetotactic bacteria create tiny crystals made of the iron-rich minerals magnetite or greigite. The crystals help them navigate the changing oxygen levels in the water body they reside in.

What did the study find?

  • The three-metre-long sediment core from the southwestern Bay of Bengal consisted mainly of “pale green silty clays,”.
  • Researchers reported finding abundant benthic and planktic foraminifera — single-celled organisms with shells found near the sea bed and free-floating in water.
  • The microscopy also confirmed the presence of ‘conventional’ magnetofossils along with giant ones. 
  • At a depth of around 1,000-1,500 m, the Bay of Bengal has a distinctively low oxygen concentration.
  • Analysis of the sediment sample confirmed fluctuations in the monsoon took place as the scientists found particles of magnetic minerals from the two distinct geological periods.
  • The rivers Godavari, Mahanadi, Ganga-Brahmaputra, Cauvery, and Penner, which empty into the Bay of Bengal, played a crucial role in the formation of the magnetofossils.
  • The nutrient-rich sediment carried in by these rivers provided a sufficient supply of reactive iron, which combined with the available organic carbon in the suboxic conditions of the Bay of Bengal to create a favourable environment for the growth of magnetotatic bacteria.
  • The freshwater discharge from these rivers along with the other oceanographic processes, like eddy formation, rendered the oxygen content in these waters that isn’t usually found in other low-oxygen zones.
  • The scientists also said the presence of the magnetofossils showed that the suboxic conditions of the Bay of Bengal persisted for a long time, allowing the bacteria to thrive.

Q1) What are Prokaryotes?

These are organisms whose cells lack a nucleus and other organelles. Prokaryotes are divided into two distinct groups: the bacteria and the archaea, which scientists believe have unique evolutionary lineages. Most prokaryotes are small, single-celled organisms that have a relatively simple structure.

Source: Goa scientists find 50,000-year-old magnetic fossils in Bay of Bengal