Advanced New Zealand
Fiordland
A dark layer of fresh water over the sea, and black coral at ten meters
It rains so much on these mountains that the fresh water, stained brown by the vegetation, forms a permanent layer several meters thick over the sea. That layer blocks the light, and underneath it, organisms that anywhere else in the world live at hundreds of meters grow at just ten.
In this profile you'll find out what deep-water emergence is and why it makes Fiordland a unique case, what it's like to cross the fresh water layer, what you'll see below it, how cold the water really gets, and what training the destination requires.
It's one of the few places on the planet where deep-sea communities are accessible to a recreational diver, and for that very reason a site of enormous scientific value and extreme fragility.
Geography and access
Fiordland occupies the southwest of New Zealand's South Island: a system of glacier-carved fiords, with rock walls that plunge straight down from the mountains to hundreds of meters underwater.
The region receives some of the highest rainfall on the planet. All that rain runs down the rock, carrying tannins from the vegetation, and settles on top of the salt water, which is denser, forming a tea-colored surface layer of fresh water.
That layer can be several meters thick and blocks much of the light. Below it, the salt water sits in permanent dim light even at shallow depth.
The resulting phenomenon is called deep-water emergence: organisms adapted to darkness and normally found at hundreds of meters, such as black coral colonies, grow here at just ten to fifteen meters.
Access is difficult: a long road to the reachable fiords, or a boat crossing. There are few operators, and much of the diving is done on multi-day trips.
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