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Franz Josef Tours – Lake Mapourika: One giant mirror!

Franz Josef Tours – Lake Mapourika: One giant mirror!

by | Aug 30, 2019

Lake Mapourika is a lake like no other. Found on the West Coast only 10 km north Franz Josef Glacier. You may have seen pictures of its famously mirror like surface perfectly reflecting snow capped mountains and rainforest. You may find yourself asking, “How is it so glassy?”

As soon as you get onto Lake Mapourika you will notice the colour of it – a deep black. You may think it’s just dirty, but as you start paddling you’ll find the water is amazingly clear! But why this black appearance?

The answer is: Tannin – a yellowish or brownish bitter-tasting organic substance present in some galls, barks, and other plant tissues, consisting of derivatives of gallic acid.

The term tannin comes from an Old High German word (Tanna) for oak or fir tree. This refers to the use of wood tannins from oak in tanning animal hides into leather. Hence the word “tan” or “tanning” for the treatment of leather.


Tannins in Food

Tannins are either bitter or acidic in taste and present in many commonly found food and drinks worldwide. When drinking red wine or tea, you may come across the dry feeling in the mouth that is caused by tannins.  Most human dietary sources of tannins are tea or coffee. Wines aged in charred oak barrels posses tannins that are absorbed from the wood adding to its bitterness. Also found in beer tannins originate mostly from the malt and hops. Nuts, such as hazelnuts, walnuts or pecans as well as herbs and spices like cloves, cumin, thyme, vanilla and cinnamon.

Importance in Nature

Tannins are widely distributed in many species throughout the plant kingdom. The New Zealand Native ‘Rimu’ and ‘Kamahi’ are known to have high concentrations of tannins. Found throughout the rainforest surrounding Lake Mapourika, it’s believed that they function as pesticides and in plant growth regulation.

Once believed to act as an anti-herbivore defense, tannins are now recognized as important controllers of decomposition and nitrogen cycling processes.

The tannins from decaying vegetation and leaves around Lake Mapourika are washed through rainfall into the lake, giving it its black tan.

Like most things out on the West Coast the weather plays an important role in providing the perfect conditions for those glassy days. Sheltered by the mountains to the east and the rain-forest to the west, Mapourika is well protected from strong gusting onshore coastal winds and alpine storms.

Combine complex biological processes with the right weather conditions, and Lake Mapourika transforms into one giant mirror!

BOOK NOW to come and check out this amazing scenery reflected in one giant mirror!