Focused experiments demonstrated that the Sri Lankan Land Mass (SLLM), situated in the southeastern part of the Indian peninsula, actively blocks long-period swell waves from the Southern Ocean from reaching India’s southeast coast. Photo: Google Maps

Schools and colleges in Puducherry and parts of Tamil Nadu will remain closed tomorrow, with the possibility of a cyclone hitting the coastal areas.

Here are the top 10 points in this story:

Bhubaneswar/Kolkata:

A deep depression over east-central Bay of Bengal intensified into cyclonic storm ‘Dana’ on Wednesday morning, the India Meteorological Department (IMD) said.

The storm is likely to move in a northwestward direction, intensify further into a severe cyclonic storm over northwest Bay of Bengal and cross the Odisha-West Bengal coasts between Puri and Sagar Island in the early hours of October 25 with wind speeds of up to 120 kmph, the IMD added.

The system lay 560 km southeast of Paradip and 630 km south-southeast of Sagar Island at 5.30 am, it said.

Advising fishermen not to venture into the sea from October 23 to 25, the Met warned that wind speed is likely to reach 60 kilometres per hour (kmph) along and off Odisha-West Bengal coasts from October 23 and gradually increase to 100-110 kmph, gusting to 120 kmph, from October 24 night till October 25 morning.

More than 150 express/passenger trains running through South Eastern Railway jurisdiction have been cancelled in view of the severe cyclonic storm, an SER official said.

The trains cancelled were scheduled to depart their originating stations between October 23 and 25, the SER official said and added that more trains running through the SER zone may be cancelled if the situation demands.

The Kolkata-headquartered SER zone is spread over the states of West Bengal, Odisha and Jharkhand.

The Indian Coast Guard (ICG) said it is on high alert and has mobilised its vessels and aircraft to respond swiftly to any contingency over the Bay of Bengal.

It said the ICG has mobilised its vessels and aircraft, positioning them strategically to respond swiftly to any emergency situations. The NDRF said it has deployed 13 teams so far across south Bengal to respond to any emergency situation.

The storm is likely to bring very heavy rainfall in south Bengal districts on October 24 and 25, the IMD said.

Heavy to very heavy rainfall with extremely heavy downpour at one or two places is likely in the coastal districts of South 24 Parganas, Paschim Medinipur, Purba Medinipur and Jhargram districts.

Heavy to very heavy rainfall is likely in Kolkata, Howrah, Hooghly, North 24 Parganas, Purulia and Bankura districts between October 24 and 25, the Met said. 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

New Delhi:

A low-pressure system over the Bay of Bengal has intensified into cyclonic storm ‘Remal’ and is expected to make landfall between West Bengal’s Sagar Island and Bangladesh’s Khepupara at midnight on Sunday, the IMD said.

This is the first cyclone in the Bay of Bengal this pre-monsoon season.

The deep depression over the east-central Bay of Bengal intensified into a cyclonic storm ‘Remal’ and was centred approximately 360 km south-southeast of Khepupara and 350 km south-southeast of Sagar Island, according to an update issued by the India Meteorological Department (IMD) at 7:50 pm on Saturday.

The storm is likely to intensify further into a severe cyclonic storm by Sunday morning and is expected to cross the West Bengal and adjoining Bangladesh coasts between Sagar Island and Khepupara with wind speeds of 110 to 120 km/hr, gusting to 135 km/hr around midnight on Sunday, the IMD said.

The Met Office has warned of extremely heavy rainfall in the coastal districts of West Bengal and north Odisha on May 26-27. Parts of northeast India may also experience extremely heavy precipitation on May 27-28.

A storm surge of up to 1.5 meters is expected to inundate low-lying areas of coastal West Bengal and Bangladesh at the time of landfall.

The weather office advised fishermen not to venture into the sea in the north Bay of Bengal until the morning of May 27.

A red alert was issued for the coastal districts of South and North 24 Parganas in West Bengal for May 26-27, where extremely heavy rain is expected in some areas.

An orange alert is in place for Kolkata, Howrah, Nadia, and Purba Medinipur districts, warning of wind speeds of 80 to 90 km/hr, gusting to 100 km/hr, and heavy to very heavy rainfall at some places on May 26-27.

In north Odisha, the coastal districts of Balasore, Bhadrak, and Kendrapara will receive heavy rains on May 26-27, while heavy precipitation is likely in Mayurbhanj on May 27.

The IMD has warned of localised flooding and significant damage to vulnerable structures, power and communication lines, kutcha roads, crops, and orchards in South and North 24 Parganas districts of West Bengal.

People in the affected areas have been advised to remain indoors. 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Needle, spindle, bullet and spearhead shape-magnetofossils.
| Photo Credit: Kadam, N et al/Nature

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. 

What are magentofossils?

Magnetofossils are the fossilised remains of magnetic particles created by magnetotactic bacteria, also known as magnetobacteria, and found preserved within the geological records.

Magnetotactic bacteria are mostly prokaryotic organisms that arrange themselves along the earth’s magnetic field. These unique creatures were first described fairly recently, 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. The crystals help them navigate the changing oxygen levels in the water body they reside in.

The fossils left behind by the crystal-creating bacteria help scientists glean conditions that prevailed millions of years ago and which contributed to “the sediment magnetic signal”.

What makes the Bay of Bengal sediment special?

In 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.

In fact, the origin of giant magnetofossils has stayed a mystery. Most giant magnetofossils have been found in sediments dating to the late Palaeocene period, some 56 million years ago, suggesting they formed only during periods of extreme warming.

But in the new study, published in the journal Nature in February, the scientists found the sediment in the Bay of Bengal to be from the late Quaternary period, or about 50,000 years ago, making it the youngest giant magnetofossil to have been found found yet.

What did the study find?

In the study, scientists at the CSIR-National Institute of Oceanography, Goa, combined magnetic analyses and electron microscopy to study the sediment sample.

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.

High-resolution transmission electron microscopy revealed the fossil to be in the shape of needles, spindles, bullets, and spearheads. 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.

Earlier, studies of sediments suggested that nearly 29,000 to 11,700 years ago, during the last Glacial Maximum-Halocene period, the northeast and southwest monsoon strengthened and resulted in significant weathering and sedimentation.

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 scientists also suggested 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.

Needle, spindle, bullet and spearhead shape-magnetofossils.
| Photo Credit: Kadam, N et al/Nature

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. 

What are magentofossils?

Magnetofossils are the fossilised remains of magnetic particles created by magnetotactic bacteria, also known as magnetobacteria, and found preserved within the geological records.

Magnetotactic bacteria are mostly prokaryotic organisms that arrange themselves along the earth’s magnetic field. These unique creatures were first described fairly recently, 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. The crystals help them navigate the changing oxygen levels in the water body they reside in.

The fossils left behind by the crystal-creating bacteria help scientists glean conditions that prevailed millions of years ago and which contributed to “the sediment magnetic signal”.

What makes the Bay of Bengal sediment special?

In 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.

In fact, the origin of giant magnetofossils has stayed a mystery. Most giant magnetofossils have been found in sediments dating to the late Palaeocene period, some 56 million years ago, suggesting they formed only during periods of extreme warming.

But in the new study, published in the journal Nature in February, the scientists found the sediment in the Bay of Bengal to be from the late Quaternary period, or about 50,000 years ago, making it the youngest giant magnetofossil to have been found found yet.

What did the study find?

In the study, scientists at the CSIR-National Institute of Oceanography, Goa, combined magnetic analyses and electron microscopy to study the sediment sample.

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.

High-resolution transmission electron microscopy revealed the fossil to be in the shape of needles, spindles, bullets, and spearheads. 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.

Earlier, studies of sediments suggested that nearly 29,000 to 11,700 years ago, during the last Glacial Maximum-Halocene period, the northeast and southwest monsoon strengthened and resulted in significant weathering and sedimentation.

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 scientists also suggested 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.

Bhubaneswar (Odisha):

The Indian Meteorological Department (IMD) on Tuesday said that the Cyclonic Storm ‘Hamoon’ has now intensified into a severe cyclonic storm over the Northwest Bay of Bengal.

As per the information from IMD, the Cyclonic Storm ‘Hamoon’ over Northwest and adjoining Westcentral Bay of Bengal moved northeastwards with a speed of 18 km per hour during the past 6 hours.

The cyclonic storm after moving for six hours, intensified into a severe cyclonic storm and lay centred, at 2:30 am on October 24, over the northwest Bay of Bengal, near latitude 19.3°N and longitude 88.4°E, about 210 km east-southeast of Paradip (Odisha), 270 km south-southeast of Digha (West Bengal) and 350 km south-southwest of Khepupara (Bangladesh).

The cyclonic storm is very likely to move nearly north-northeast wards and cross the Bangladesh coast between Khepupara and Chittagong around noon on October 25 as a Deep Depression.

Earlier, on Monday, the Municipal Administration in Odisha had put all Urban Local Bodies (ULB) on alert in view of the formation of cyclonic storm ‘Hamoon’ in the Bay of Bengal.

Director Municipal Administration Sangramjit Nayak, in an official statement, issued a directive to all ULB Chiefs, sensitising them about the impending danger due to the formation of cyclonic storm ‘Hamoon’ in the Bay of Bengal, which will culminate in huge rainfall, wind, and inclement weather.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)