Eruption poses threat to huge penguin colony

chinstrap penguin
A chinstrap penguin on Deception Island. @bberwyn photo.

British Antarctic Survey scientists to monitor impacts of ash deposits

Staff Report

A volcanic eruption in the remote South Sandwich archipelago, near the tip of the Antarctic Peninsula, may threaten the largest known colony of chinstrap penguins, according to scientists with the British Antarctic Survey who have been monitoring the eruption.

The Mt. Curry volcano on Zavodovski Island has been erupting since March, sending ash toward the penguin enclave. The uninhabited island is part of the British Overseas Territory of South Georgia and the South Sandwich Islands. After reports of a 7.2 magnitude earthquake last month, researchers confirmed from satellite imagery that not one, but two volcanoes are erupting in the South Sandwich Islands — Mt. Curry on Zavodovski Island to the north of the archipelago and Mt. Sourabaya on Bristol Island to the south.

Photos taken by fishing boats in the area show the main volcanic vent is on the western side of the island, but the prevailing wind is blowing the smoke and ash to the east, and depositing much of it on the lower slopes of the volcano. These are home to the chinstraps, closely packed in great numbers. In addition there are around 180,000 macaroni penguins.

Satellite images have confirmed that between one third and one half of the island has so far been covered in ash. At the time photos were taken, the adult chinstraps were moulting, shedding their old feathers for new ones and therefore unable to leave the island.

Geographer Dr. Peter Fretwell from BAS who was involved in the remapping of the archipelago said, “We don’t know what impact the ash will have on the penguins. If it has been heavy and widespread it may have a serious effect on the population. It’s impossible to say but two scientific expeditions are scheduled to visit the region from later this year and will try to assess the impact of the eruption.”

“As the images were captured during the moult period for the chinstraps, the consequences could be very significant,” said penguin ecologist Mike Dunn, with the BAS. “When the penguins return to breed later in the year, it will be interesting to see what impact this event has on their numbers.”

Chinstrap penguins (Pygoscelis Antarctica) are one of the brush-tailed penguin species common around the Antarctic Peninsula and Scotia Sea. The global adult population of Chinstraps was estimated at over seven million pairs in 2013.

The South Sandwich Islands are the emergent parts of volcanoes forming the volcanic arc of a subduction system in the Scotia Sea, a compact ocean gateway region of global significance for interactions between tectonics, oceanographic flow, climate and biodiversity during Cenozoic to recent times.

This is the first time that Zavodovski Island has been witnessed erupting, although there is evidence that it erupted in the 1970s, possibly in the 1980s and as late as 2012, although the nature of those eruptions is unknown.

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