Barren Island: India’s Lone Volcano and its Adjacent Underwater World
Photo StoryPublished : Feb 24, 2023Updated : May 02, 2023
Underwater life around this desolate and actively volcanic island in the Andamans is colourful and diverse
Text by: Nitya Prakash Mohanty and Adhith Swaminathan
Underwater life around this desolate and actively volcanic island in the Andamans is colourful and diverse
Through the ages, volcanoes have captured the human imagination and assumed almost mythical grandeur in history. From the fall of Pompeii due to Mount Vesuvius erupting to the under-glacier volcano in Iceland that brought air travel in Europe to a grinding halt for almost a week in 2010, volcanoes inspire awe as much as they wield devastation. Scientific research has shown that the Indian Ocean is the theatre of the longest period of volcanic activity in Earth’s history, with a network of volcanoes erupting for nearly 30 million years, releasing lava that could fill 5.5 trillion Olympic-sized swimming pools. Several active volcanoes still reign over the Indian Ocean, and those that erupt regularly are found off Reunion Island, and closer to home, on Barren Island, in the Andaman Sea.
Barren Island lies 70 km to the east of the Andaman Islands and 130 km away from the capital city of Port Blair. With its first-recorded volcanic activity in 1787, Barren Island got its name due to the scorched-earth appearance of most of its land area. The volcano rises two kilometres from the sea floor but is only 350 m above sea level. Although not as prolific in eruptions as its other Indian Ocean counterparts, such as the Piton de la Fournaise in La Reunion, which is active most years, Barren Island remains significant as the only active volcano on the north-south volcanic arc between Sumatra and Myanmar, a region that witnessed the devastating tsunami of 2004. Given the fact that volcanic activity and tsunamis can occur together, it is important to monitor this volcano. The other volcanic island in this region, Narcondam Island, lies 130 kilometres north of Barren but it has not seen any volcanic activity for thousands of years.
Being the lone active volcano in the region, Barren Island holds immense attraction for geologists. Recent geological surveys have uncovered several missing pieces of this island’s ancient origin, including dating the birth of this volcano to 1.8 million years ago. While volcanoes are fascinating in themselves, the surrounding underwater landscape includes caves and sheer drops that run several hundred metres with unpredictable down currents. There is an incredible diversity of marine life surrounding the island. It could be a haven for photographers, game fishers, snorkellers and scuba divers who come to the Andamans in the hope of exploring the hidden treasure of the sea, but fortunately for the pristine region, travel permits are hard to obtain and accessibility is difficult.
Barren Island is a roughly circular island, three square kilometres in size, with a starkly barren west front, which is the usual route its lava flow takes. This volcanic zone is devoid of vegetation and covered in sharp basaltic rocks that cover nearly half its area. The only human-made structure on this island used to be a lighthouse on the western side which was obliterated when the volcano sprung to life in 1991. The southern aspect of the island is much more forgiving, harbouring a forest and cold springs. Photo: Dhritiman Mukherjee
The active volcano on Barren Island erupts frequently, the lava flow leaving in its wake charred earth and specs of lime green sulphur. However, the volcano was not always covered with tufts of smoke, as it had lay dormant for 159 years, until 1991. Since then, the island has witnessed numerous eruptions, with the last one in 2020. Lava flows of the many eruptions appear starkly different and have created unique terrain such as rainbow-coloured caves and steep walls. The dramatic lava flows, down the 350-m slope, can also be traced underwater, apparent in the blackened and cracked rocks — an eerie sight indeed. Photos: Dhritiman Mukherjee (1), Adhith Swaminathan (2,3)
Life underwater is not as barren as on the surface. Unlike other parts of the Andaman and Nicobar Islands, where the seabed is predominantly white, the colourful and abundant coral life here pops out against the dark ash-like black sand. On the western part of the island, where lava has historically been directed, there are vast patches of hard coral. The nutrient-rich surrounding water supports extensive coral forests with a variety of hard and soft corals, which are probably resilient to extreme water temperatures. Photos: Dhritiman Mukherjee
The Andaman archipelago is home to an abundance of marine life. The life underwater around Barren Island is colourful and very diverse. Scuba divers spot giant clams (1), sea kraits, schooling fish, sharks, and manta rays (2), while deeper waters bring a wide array of pelagic species of fish, whales, dolphins, and sharks. As the island is surrounded by open sea, giant oceanic mantas (Mobula birostris), not commonly sighted across the archipelago, are known to make an appearance. Giant mantas are the largest rays (can grow up to nine metres) and often undergo long migration in search of plankton. Photo: Dhritiman Mukherjee; video: Umeed Mistry
Open-sea birds such as the (1) white-bellied sea eagle (Haliaeetus leucogaster) and the (2) black-naped tern (Sterna sumatrana) are a common sight along Barren Island. However, little is known about the biodiversity on the island. The few expeditions to the island have reported pied-imperial pigeons, parakeets, fruit bats, and human-introduced rats and goats that have become feral. The case of the feral goats of Barren Island is a curious one, and there was once much speculation about their introduction to and survival on the desolate island, possibly without any freshwater source. However, it is now known that the goats were left on the island by a steamer in 1891; and the mystery of goats living without any potential source of water was solved when geologists found cold springs with the goats grazing around them. Goats have been introduced in islands the world over, as in the past, they served as food sources for voyagers. Apart from goats, introduced herbivores on the other islands of the Andaman chain (not Barren) include the spotted deer (Axis axis) and barking deer (Muntiacus muntjak). Photos: Dhritiman Mukherjee (1), Adhith Swaminathan (2)
India’s lone active volcano has the potential to draw tourists but there are lots of restrictions for visitors, driven in part by considerations of safety which prohibit any landing on the island. While the seas around Barren Island were used for game fishing, scuba diving and snorkelling in the past, with even a government-run ferry service in place a few years ago, this is not the case anymore. This enigma in the Indian Ocean remains one of the least explored of the archipelago. Photo: Umeed Mistry
About the contributors
Nitya Prakash Mohanty
Nitya is a researcher interested in the ecology of sleep, animal behaviour, invasive species and all things fascinating in the natural world.
Adhith Swaminathan
has been working with sea turtles since the age of 10 and is currently working with Dakshin Foundation conducting research on leatherback turtles in the Andaman and Nicobar Islands.
