Page 27 - Discover Botswana 2022 ONLINE

When you hold between two fingers a tiny grain of sand picked up somewhere in the Okavango, and analyse it, you may be justifiably confused. The minute quartz grain in
your hand is transparent and mostly devoid of colouration. In truth, what you see is a mirror image of an ecosystem leeched of its nutrients, stripped bare of the building blocks of life that would normally force everything within it to continually search for sustenance. Why then does the Okavango hold so much life, if what we see on the surface indicates just the opposite?
THE NUTRIENT DEFICIENCY:
Geographically, the Okavango is positioned in an ecoregion that has one of the lowest carrying capacities south of the Sahara. If it weren’t for the ancient alluvial nutrient deposits locked into the old riverbeds of the Kalahari, the once numerous herds of ungulates moving across the plains with the cycles of rain would not have existed, and the Kalahari would appear wholly desolate. Clearly, an area of similar poor- quality soil and rainfall would be expected to have a carrying capacity about ten times lower than the Okavango.
The answer may lie simply with water, and the annual cycling of the floodwaters originating upstream in Angola. This water is exceptionally clean. When it eventually reaches the Okavango, it is in fact so pristine that it is 15-20 times purer than what is globally considered ideal drinking water! This may seem like a perfect scenario, but in fact it further reveals the truth of the delta and its nutrient ‘deficiency’. The vast beds of papyrus act as the most perfect filter, and whatever minerals, nutrients and floating solids that are still suspended in the water are trapped by this ancient sedge. Our tiny grain of sand is so clean that the water running over it will only shift its position as there is nothing left to dissolve from it. How then does life thrive in the delta? The answers lie in a few key indicators.
Previous pages: When drying pools scatter across the Okavango during winter, large pools of trapped fish can attract both species of Pelicans which in certain cases fly hundreds of kilometres in search of these hidden gems.
Left: A Okavango lover, Open bill storks wander the shallows mostly in search of Fresh Water Snails which they crack open using their specialized beaks.
OKAVANGO
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