What is the news?

Scientists from the CSIR-National Institute of Oceanography, Goa have found in the Bay of Bengal a 50,000-year-old sediment containing giant magnetofossils, shedding light on ancient geological conditions.

What are Magnetofossils?

• Magnetofossils are fossilized magnetic particles created by magnetotactic bacteria, aiding scientists in understanding past environmental conditions.
• Described initially in the 1960s and 1970s, magnetotactic bacteria utilize iron-rich minerals to navigate the Earth’s magnetic field, leaving behind distinctive fossil remnants.
• These unique creatures were first described in 1963, by Salvatore Bellini, an Italian doctor and then again in 1975 by Richard Blakemore of the Woods Hole Oceanographic Institution, Woods Hole, Massachusetts.
• These organisms were believed to follow the magnetic field to reach places that had optimal oxygen concentration.
• Using an electron microscope, Blakemore found the 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, aiding them in navigating changing oxygen levels in the water body they reside in.

Special Attributes of Bay of Bengal Sediment

• Previous studies on magnetofossils often ascertained their origins to be hyperthermal vents, comet impacts, changes in oceanic ventilation, weathering or the presence of oxygen-poor regions.
• Sediments deposited at the core site originate from the Godavari, Krishna, and Penner Rivers, highlighted on the map.

Findings of the Study

• Scientific Approach: In the study, combined magnetic analyses and electron microscopy to study the sediment sample.
• Sediment Characteristics: The three-metre-long sediment core from the southwestern Bay of Bengal consisted mainly of “pale green silty clays,” they wrote in their paper. They also reported finding abundant benthic and planktic foraminifera — single-celled organisms with shells found near the sea bed and free-floating in water.
• Microscopic Revelations: High-resolution transmission electron microscopy revealed the fossil to be in the shape of needles, spindles, bullets, and spearheads.
• Environmental Insights: Earlier, studies of sediments suggested that nearly 29,000 to 11,700 years ago, during the last Glacial Maximum-Holocene period, the northeast and southwest monsoon strengthened and resulted in significant weathering and sedimentation.

PYQ:

Consider the following kinds of organisms:

1. Copepods
2. Cyanobacteria
3. Diatoms
4. Foraminifera

Which of the above are primary producers in the food chains of oceans?

1. 1 and 2
2. 2 and 3
3. 3 and 4
4. 1 and 4

Practice MCQ:

Which of the following statements is correct about the ‘Magnetofossils’?

1. They are fossilized magnetic particles created by magnetotactic bacteria.
2. They follow the magnetic field to reach places that have optimal oxygen concentration.
3. They are tiny crystals made of the iron-rich minerals magnetite or greigite.
4. All of these.

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