Huge iceberg ‘threatens sea-life’
A vast iceberg that broke off eastern Antarctic earlier this month could disrupt marine life in the region, scientists have warned. They say the iceberg, which is 78km long and up to 39km wide, could have consequences for the area’s colonies of emperor penguins. The emblematic birds may be forced to travel further afield to find food. The iceberg calved from the Mertz Glacier Tongue after it was hit by another huge iceberg, called B9B. “It is a very active area for algae growth, especially in springtime,” explained Dr Neal Young from the Australia-based Antarctic Climate and Ecosystems Co-operative Research Centre. “There are emperor penguin colonies about 200-300km away to the west. They come to this area to feed, and seals in the area also come to get access to the open water,” he told BBC News. He suggested that a change in the availability of open water could affect the rate of food production, which would have an impact on the amount of wildlife it could sustain. “If the area gets choked up (with ice), then they would have to go elsewhere and look for food.” … Before the formation of the iceberg, the Mertz Peninsula provided the right conditions for a polynia – an expanse of open water surrounded by sea-ice – to exist. “Winds blow off the coast and clear anything in that region, including sea ice, exposing open water,” Dr Young explained. He added that as well as providing a feeding site for the region’s wildlife, the polynia also was a key production site of “bottom water”; very cold, dense water that sinks to the ocean floor. “Sea ice is relatively fresh compared to sea water, so the more sea ice you have (in the surrounding area), the more salt that is left in the remaining open water.” The rise in the concentration of salt increases the water’s density, causing it to sink to the bottom of the ocean. “This area around the Antarctic coastline, of which the Mertz Peninsula is one part, produces about one quarter of the Antarctic’s bottom water, but the Mertz polynia is a major contributor,” Dr Young said. He added that the new iceberg had shortened the length of the Mertz Glacier Tongue, which could result in pack ice entering the area and disrupting the polynia. “That means that the bottom water production rate… will decrease. …
