死亡冰柱 所到之处瞬间冰封

死亡冰柱所到之处瞬间冰封

南极长年冰天雪地，人迹罕至，不少奇怪异象都是世人从未见过，英国广播公司( BBC)摄制队，早前首次在南极海底拍摄到“死亡冰柱”( icicle of death)，冰柱下沉到海床后，所到之处周遭的海水都会凝结，海胆、海星全被冻死，蔚为奇观。

其实这种死亡冰柱自1960年代已开始存在，通常当南极海洋混入了带盐份的水后就会出现，不过今次还是首度有人拍摄到这个奇景。拍摄当日，海底水温只得-2℃，BBC摄影师米勒( Hugh Miller)及安德森( Doug Anderson)在南极罗斯群岛( Ross Archipelago)的小剃刀背岛( Little Razorback Island)海中，亲眼目击死亡冰柱的形成过程。由于冰柱的密度较海水高，因此一直朝海床沉下，并迅速扩张，周遭接触到冰柱的海水随即变冷凝固，但看上去像海绵状多过普通海冰，而附近的海洋生物，如海胆及海星等，因冰柱的温度太低而全被冻死。

米勒忆述当日亲眼目击冰柱沉下并迅速扩张，仍感到有点难以置信，“这情况有点像与时间竞赛，因为没有人真正知道它们形成得有多快。我们一星期前看到的那条冰柱，在我们面前迅速扩张变长，整个过程只用了5、6小时”

Remarkable broadcast moment: The ice begins to expand outwards. The brine is a lot more dense than seawater so sinks to the bottom. It is also a lot colder- causing the freezing

Touchdown: The brinicle reaches the ocean floor.Starfish can be seen. Often the brinicles break up before they become so large

Killer: The ice floods outwards across the ocean surface rapidly, destroying everything in its wake

Destruction: The starfish are frozen by the ice as it expands outwards

Broadcasting feat: Although the existence of brinicles has long been known it is the first time they have ever been caught on camera

Seabed spread: When the seawater freezes as it comes into contact with the brinicle it is a lot more spongelike than normal ice