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THE NUTRIENT SINK:
There are several factors that form the nucleus of this miracle and help solve the mystery of the Kalahari. A few of the most important ones are:
Water: There is nowhere that the old adage of ‘water brings life’ is more relevant than here in the Okavango, a wet eco region smack in the middle of the Kalahari drylands. Interestingly however, water here is not purely for hydration, it creates the platform essential for the uptake, dispersal and activation of nutrients. Perhaps just as importantly, it also houses zooplankton, the building block component of the delta that allows all life to thrive.
Dust: Believe it or not, an estimated 250 000 tonnes of dust is blown in over the Okavango annually, bringing with it vital deposits of nitrogen and phosphorous, building blocks of life that are represented poorly in the delta.
Papyrus: Papyrus is perhaps one of the most important ecosystem engineers of the Okavango Delta. It is not only the gatekeeper of the Okavango’s nutrients, but it plays a significant role in hydrological dynamics and the deviation of channels and flow rates. Perhaps even more than tectonic activity, papyrus may play a significant role in how the main arteries and their respective flow rates affect the rest of this alluvial fan. It ‘locks’ valuable nutrients within its waterproof stems through the uptake of water and helps filter out any sediments that enter the deep peat beds of the uppermost Okavango panhandle. These nutrients remain unavailable to most species until the plants eventually die and are decomposed by anaerobic bacteria, releasing the locked nitrogen and phosphorous which then become available for other organisms downstream.
Below: Large Buffalo herds are a lifeline for the delta. They play an important ecological role for the environment of the Okavango.
Facing page right: When winter falls over the Kalahari, the difference between temperatures can be extreme. A simple example when mammal breath turns to steam in the early morning light.
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