Rukwa

From being under the high point of Africa, Mt Kilimanjaro, I am now at Kipili beside the low point. The Great Rift Valley here is submerged by Lake Tanganyika, (named from Tanganika, "the great lake spreading out like a plain",) whose bottom in this southern basin lies 642 meters below sea level; a depth of 1470 m. About 18% of the world’s unfrozen surface freshwater is held in it.

The area first came to the attention of Europeans when the famous Welsh actor, Richard Burton stumbled upon it with his fellow thespian, Richard Speke, whilst making "Mountains of the Moon". More recently, you might have seen a Monty Python version called "Pole to Pole" where a slightly stunned Michael Palin sails the length of the lake on the ferry, MV Liemba. Rumour has it that David Livingstone was also on location here, but I can find no mention of any film of that in IMDb.

The scenery is as pleasant as you would expect; but doesn't reveal it's uniqueness, so here are some "fun facts" for the next Trivial Pursuits game in your local pub.
⦁ It is the longest fresh water lake in the world and the second deepest after lake Baikal in Russia.
[depth = 1433 m / 4700 ft; length = 677 km / 420 miles; width = 50 km/ 31 miles]
⦁ its somewhere between 9 to 12 million years old, though some claim the bottom waters may be over 20 million
⦁ the Rift Valley here has formed three basins without any drainage: the contents either evaporates or overflows
⦁ the lake surface may have fluctuated up to 300 meters lower at than it is today: with the high evaporation rate it rarely overflowed into the 320 km Lukuga tributary of the Congo River and the sea. On average water remains in the lake for 440 years.
⦁ Tanzania’s second largest river, the 475 km Malagarasi River, is older than the lake. It used to flow directly into the Congo River from the East but now is captured by the lake.
⦁ Life has not yet been found in the bottom 1200 meters of the lake as it is too high in hydrogen sulphide or too low in oxygen. But I'm haven't found anybody who has looked.
⦁ Unusually, the water in the lower depths is only 3° C colder than the 25° C surface temperature. Nobody knows why.
⦁ Winds can stir things up a bit, even causing 6m waves during storms; which helps stop bilharzia snails spreading but doesn't mix the layers of water up very much.
⦁ The nutrient carried into the lake is negligible; fish rely on algae fed by nutrients rising from the bottom.
⦁ There are over 350 species of fish, 95 % endemic, (4 predatory and 2 types of sardine,) as well as indigenous snails, shrimps and crabs. The lake's incredible diversity makes it an important resource for the study of speciation in evolution.
⦁ The locals say that the crocodiles - freshies not salties luckily - and hippos generally don't cause a problem except perhaps at dawn and dusk.
⦁ All the usual invasive plants, such as lantana, duckweed and the toon tree, can be found choking the shoreline. Surely some, like the coffee senna, the castor oil plant and my favourite, the Nile Cabbage could be harvested?Read more