It was the beginning of winter in Namibia, but one did actually feel it in Central-Northern Namibia. In comparison to where I live in Windhoek, the temperature felt like that of early spring or late summer. But it did not matter really, because, in June 2014, I found myself working mostly beneath the ground surface – not in a mine, but in a sinkhole lake.
It was just before the mid-semester exam time, and so I had my doubts of the amount studying that I would be doing once I was up there, but I reasoned that I would be able to study on the road and in my spare time. My main tasks would be to help in setting up camp and to assist with the diving survey that was going to take place there; also I was to help in measuring the depths of the lake, and to help in seeing what biodiversity there was in the subterranean system (the divers would see what critters they could find at the bottom). Not many people actually new about this Aikab sinkhole lake (which in Namibia is second in size to the Dragon’s Breath Cave Lake) mainly due to it being in a part of the National Park that only the staff were allowed to access — and even fewer people (including those that worked in the Park) had actually seen it. So when I was asked to join and help assist (my friend, the Park Warden, thought it would be a good experience for me) I couldn’t believe the luck I had (especially since it fell within my study block week).
When we departed, one couldn’t miss the amount of equipment that was being brought along both in the 4×4 bakkies and the trailers. Besides our equipment and tents, there were other boats, the diving equipment, the oxygen tanks, the makeshift diving platform, etc. It was all necessary, but getting the equipment down to the lake was more of a challenge (getting it up later was even more strenuous). Aikab is not an open sinkhole lake (hemi-cenote) – most of it is covered by the dolomite rock layers that are typical to that area. But there is one small portion of the lake that is open due to the fault-line that runs next to it, but that meant that only less than 5% of the surface water could be seen from the top of the “crater”. Nevertheless, we were able to lower most of the equipment using a pulley that hung directly above the entrance to the lake. And for the next five days, we like others before us, explored on dark clear water of Aikab.
Exploring the lake was, to say the least, a once in a lifetime opportunity. The lake had water so clear, that one could see the divers at the bottom of the lake (which was 40 metres below us). Besides the stalactites that hung from the sides of the cavern, and the bats that constantly flew across the water’s surface, there was the echoing sounds that always created an otherworldly atmosphere – it’s no wonder that the Khoisan people consider these cave systems the entrance to hell itself.
We collected a wealth of information from the lake. We didn’t just measure the width and the height and the depth of the cavern. We had also sampled various species invertebrates (bat parasites mostly it would seem), plant material (from the entrance), and had identified various other bat species. The divers also found species of roundworms and other invertebrates at the bottom of the lake and had successfully mapped portions of the underwater segments – they also apparently found the skeletal remains of both a Kudu and a Python (both probably victims of thirst and the steep embankments).
In a very ironic sense, Aikab is one of various extensive underground wetland systems in a country that is typically semi-arid. Not only is it an essential water supply, but it hosts various species some of which (as it is in Lake Otjikoto, Lake Guinas, and Dragon’s Breath) are endemic; and so their protection will forever be our responsibility.