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Lake Natron

Lake Natron – One of a Kind

19 January 2009

Text and Photography By Greg du Toit

Flamingo Remains

Straddling a remote border of East Africa, lies a lunar frontier that constitutes one of the most hostile environments on planet earth. Situated just two degrees south of the equator, the surface temperatures of this lake regularly soar above 60 degrees Celsius (140 degrees Fahrenheit). The PH of the water is almost equal to that of pure ammonia and the rate of evaporation is approximately ten times that of the region’s rainfall. Photographed from space, the blistering red surface of this caustic habitat continuously changes its demeanor, looking more at home on Mars than on our own blue planet. Yet, it is in this seemingly inhospitable environment that one of mother nature’s most marvelous and discreet spectacles is hosted. Lake Natron may be the most alkaline lake in the world but it is also home to the largest breeding colony of Lesser Flamingo on planet earth.


The great discovery of the largest breeding colony of Lesser Flamingo in the world, belongs to an ornithologist by the name of Leslie Brown, who discovered the site in 1954 (also an indication as to how remote the lake is). Reading about Brown’s intrepid explorations in the book ‘Pink Africa’, the author tells the story of how Brown discovered the breeding colony, using the following words: ‘Leslie Brown nearly paid very dearly for his discovery of the Lesser Flamingoes’ breeding grounds. On his first attempt to reach a colony in Lake Natron, he burnt his feet so badly that he came close to needing a double amputation. He was disabled for six weeks and underwent numerous skin grafts’. The story goes on to say that Brown reserved a particular invective for Lake Natron and he referred to the dreadful heat to be, ‘Such as to make one wish one had never been born’! He goes on to describe the lake as being filled with ‘appalling smells, treacherous surfaces and sheer daunting size’. Both before his discovery and after his discovery, he used the following words to describe the lake: ‘evil, fetid, foul, frightful, ghastly, horrible, horrid, leprous, stinking and vile’.

Placing Brown’s ‘infectious love’ for Natron aside, residing in the southern part of Kenya’s Great Rift Valley for close on two years, I was afforded the unique opportunity of exploring and documenting Natron from her northern shores. The lake is readily photographed from space by NASA and is heralded as one of the most dynamic landforms on the planet. Images from the shore of Natron are however rare, and I set out to document this wonderfully rugged wilderness with my tripod in hand and my feet firmly planted in volcanic mud.

Natron Moran 2
Lake Natron and her surrounding piece of the Great Rift Valley are like no other place you have ever seen. The mere name is misleading as to describe this landmark as a ‘lake’ is somewhat of a misnomer and no doubt Mr Brown will concur. No, Natron is not the kind of Sunday picnic destination, associated with many other lakes. A casual swim in this lake could prove fatal and sun tanning promises to deliver third degree burns. Natron is definitely not the stereotypical oasis associated with freshwater lakes, but rather a caustic soda lake of the highest order. She is located in the far north of Tanzania and old maps may still depict part of the lake residing in Kenya. If one were to try and find the lake on a map, you would roughly aim at the chunk of wilderness lying between Mount Kilimanjaro and the Masai Mara, along the Kenyan/Tanzanian border. The lake basin itself does in fact stretch across the Kenyan border, but this constitutes nothing more than vast and empty mudflats. Lying 2001 feet above sea level, the lake is also situated in one of the more dramatic parts of Kenya’s portion of the Geat Rift Valley (to be me more precise, one should refer to this section of the valley as the Gregorian Rift).

Standing on the shore of Lake Natron, one is offered a phenomenally vast vista and almost guaranteed of being all alone (except on Tuesdays and Thursdays when passing Maasai warriors traverse their way to or from a weekly market on the Kenyan side of the border). Looking to the North, one sees Oldoinyo Shompole, an extinct volcano resembling a large mountain of molten wax. Shompole itself, has been heralded as the most unpleasant mountain in East Africa to climb. Although its summit is a mere 5131 ft above sea level, the sides of the mountain are covered in Acacia mellifera shrubs. These Acacias are the proverbial ‘wag n bietjie’ or ‘wait a bit’ thorn and promise to cling to any form of life passing by. With no distinct pathways and no defined route, it is rumoured that the Kenyan Mountaineering Club has, on previous occasions, abandoned the eight-hour summit. Shompole is therefore best viewed from the lakeshore, where its mirrored reflection provides a breathtakingly tranquil canvas. Turning to the east one sees the Gelai Caldera (another extinct volcano), while due south lies a modern day anomaly in the form of Oldoinyo Lengai, the only active volcano in the eastern arm of the Great Rift Valley. Lengai, as the volcano is affectionately called, means ‘Mountain of God’ and is also the only active volcano of its kind in the world! It is a rare carbonatite volcano producing a unique larva containing a lower silica content than other conventional volcanoes. From the northern shores of Natron, and on clear day, one can see the white larva spilling down Lengai’s face, where its reaction with atmospheric water has turned it an ashy white colour. The Maasai believe that lengai (or god) resides in high places and that the streaming larva is in fact his beard. Oldoinyo Lengai’s last spectacular eruption took place in 1967 and the crater floors have, over the past few years, been steadily rising. Currently, the volcano is almost devoid of a northern crater, signaling the labour pains of a spectacular eruption in the not too distant future?

Ol'doinyo Lengai copy
To the West of the Lake lies the impressive wall of the Great Rift Valley where the escarpment plunges 1700 metres (5576 feet) to the valley floor below. The segment of the wall that looms over the lake, is a spectacularly steep triangular mountain known by the local Maasai as Oldoinyo Sampu. This translates to mean ‘Mount of Stripes’ which describes the ancient furrows of erosion running down its wrinkled face. The same forces of erosion that have aged the face of Sampu have, for millions of years, eroded the walls of all the extinct volcanoes surrounding the lake. These erosive processes have carried large quantities of volcanic salts into the basin below, thereby securing Natron’s status, as the most alkaline lake on the planet. Initially, the lake’s main source of volcanic salts came from the violent eruptions of the then still active volcanoes, which spewed vast amounts of ash into the air, before coming to rest on the basin floor. This ancient process might indeed be repeated if Oldoinyo Lengai decides once again to erupt and the evidence no doubt points to this happening in the relatively near future!

Thousands of tons of volcanic salts are indeed only half the recipe that comprises the formation of a soda lake. The second mandatory characteristic is that the lake itself must have no outlet. This lack of an outlet is essentially what separates soda lakes from freshwater lakes in the Great Rift Valley. Lake Natron is simply a volcanic cul-de-sac, facilitating the accumulation of vast quantities of salts, creating a caustic soup ideal for algal blooms. Added to this, the lake is shallow throughout and at certain times of the year, the formation of inaccessible mudflats, make it the ideal breeding ground for flamingoes.

The lake receives some of its fresh water from underground springs and rainfall, but it relies on a single river, the Ewaso N’giro River, for its main source of fresh water. The Ewaso is birthed in the Mau Escarpment on the Kenyan Highlands and snakes its way onto the Rift floor, before spilling its contents into the Ewaso Swamps. Emerging from the swamps as a mere trickling stream, the water clings to the floor of the rift, fighting its evaporative tendencies before ending its journey on the shallow Natron basin. With nowhere to drain, the freshwater fast changes its PH status, becoming a part of the lake. Standing on the shore, the smell of this caustic water permeates the air, adding a strange olfactory dimension to this timeless wilderness. This same clinical aroma travels on the hot dry winds up the valley, depositing its strange volcanic odour many miles away. The water in the centre of Natron is alkaline in the extreme and painful soda burns await any intrepid explorers who choose to wade into the caustic soup. The only vertebrate able to thrive in this hostile environment is the White-Lipped Tilapia (Oreochromis alcilicus). The scientific name of which points to its ability to survive in water that would kill a thirsty Zebra! This beautiful little Tilapia does indeed have white lips, but it is the high PH level of its body fluids, to which it owes its caustic existence. By matching the alkaline levels of the lake, this species avoids Natron’s osmotic obsessions.

It is however, not just the White-Lipped Tilapia that thrive in such basic conditions, but also a blue-green algae belonging to the genus Spirulina. Flying over the lake, it becomes very apparent, that these algae might go by the name ‘Blue Green’ but its their coral red pigments that stand out! From above, the algal blooms resemble the lunar surface of Mars! Viewing NASSA’s satellite photographs of Lake Natron, one begins to understand the dynamic nature of algal blooms as no two photographs are the same. On areas of the basin where the water has evaporated, large pink soda flats form, radiating a pink reflection that can be viewed on the surface of overhead clouds. This same algae forms the staple diet of the Lesser Flamingoes, and is also responsible for the beautiful colouration of their plumes. The East African population of Lesser Flamingo spends most of its time on Lake Nakuru and Bogoria, where the algal blooms are unrivalled. However, when it comes time to breed, the flamingoes choose Lake Natron to be their only East African breeding ground, and indeed the largest breeding ground in the world. Numbers in excess of 2 million birds have been recorded breeding at Natron, a wilderness that affords the birds maximum safety and privacy. Standing on the shore, one cannot view the mud-cone nests of the flame-birds as they choose to breed in parts of the lake that are completely inaccessible to any form of terrestrial predator. From the eastern bank of Natron, one can however witness thousands of birds making their way to the shore where they drink and bath in freshwater, emerging from hot underground springs. These flamboyant processions of birds, offset against the strewn chunks of jet-black volcanic rock, are indeed a spectacular sight.

Flamingos taking flight
Bathing Flamingos
The flamingoes’ window for breeding is erratic and very difficult to predict. They normally breed between August and November after the long rain monssons have subsided, helping form the necessary mudflats needed for the building of nests. The lake is however incredibly temperamental and even a slight rise in water levels can cancel a breeding attempt. The lake is also incredibly shallow and too little water leaves the birds stranded with no mud to construct their nests. Therefore, while Lake Natron might be the largest breeding ground in the world for Lesser Flamingo, it is also possibly the most temperamental. Should the mudflats dry or the water rise, then the breeding attempt is certain to fail. This highly volatile breeding strategy does not afford the birds the luxury of breeding every year and it is no wonder that on the 4th July 2001, this precious pearl of Africa was given RAMSAR status. Despite this status, the delicate lake faces an uncertain future! The most recent threat to both the lake and the breeding colony is the already well-documented, proposed plan for TATA Chemicals to extract and mine soda ash (See Africa Birds and Birding Vol. 12, No. 4). While this is a glaringly obvious threat, there are many more seemingly subtle yet equally devastating and less publicised threats facing the lake:

Not only do older maps depict the lake spanning across the Kenyan border but if one visits these lake remnants today, you will find an aggressive saline grassland sneaking its way south towards the current day Natron. The lake seems to be in a pattern of recession and this becomes glaringly obvious when driving in from the Kenyan side, whereby one drives on the dry lakebed for many kilometers and far into Tanzania, before reaching any water. The lake no longer reaches the Kenyan border except during exceptional floods as experienced in the El Nino of 2000. The big question to ask is, “What is causing this pattern of recession”?

Natron Landscape
Natron Dawn
This is indeed a complicated one to answer but let us start by looking at Natron’s only significant source of freshwater. Should this be compromised, the entire lake would die, reverting to saline grassland and significantly impacting the already ‘near threatened’ global population of Lesser Flamingo. Conservation of the Ewaso N’giro River is therefore of imperative importance. In the past there have been rumoured notions of the Kenyan government possibly wanting to use the river to generate hydroelectric power, to help solve the country’s power issues. This would be a grave mistake as although the breeding birds do not directly attract tourists to the lake itself (as they breed out of sight), they do offer a major drawing card when feeding on other lakes like Nakuru. In fact, Lake Nakuru is one of the largest drawing cards on Kenya’s safari circuit, which is also the country’s number one foreign revenue earner. Therefore, assuming the Kenyan government never proceeds with the hydroelectric plant, the Ewaso N’giro is still of large concern:

The river has its source many miles away on the Mau Escarpment and towards the interior of Kenya. From there, the river snakes its way through numerous towns and villages not least of which is Narok, the largest and most prominent town on the border of the Masai Mara. The Ewaso’s banks boast some of the most beautiful Sycamore Fig forests in East Africa, and it should be a large perennial river. Both the informal take-off by people in the villages needing water to live, as well as ecologically unsound irrigation practices used to grow vegetables, are of concern. These factors combined with the vast cattle herds drinking from the river when it reaches the floor of the Rift Valley (also trampling the banks and adding silt), is also of concern. The Ewaso is at times so low and carries so much sediment, that sand banks form making it impossible to even canoe down! It is sometimes hard to believe, when viewing the Ewaso as a trickle entering Natron, that the lake exists at all. The river does however, nearing the end of its journey, contain a few deep channels closer to the Ewaso Swamps. Here too there is an issue, as the Maasai need to cross these channels with their livestock and to do so, they have built bridges using logs. These man-made logjams do not completely halter the flow, but it is hindered and with the Flamingoes’ breeding requirements being as delicate as they are, even this could adversely affect the colony. As with other areas in Africa, rivers pose a major conservation challenge as they flow across vast tracks of land and often across international boundaries. To save Natron and other ecosystems there is a real need for effective international treaties protecting rivers, which after all act as critical arteries supporting life! No more so than the Ewaso N’giro, Lake Natron’s only lifeline.

Rift Valley Wall
Sand Storm
Desertification is another major factor affecting Natron’s steady retreat. The effects of this are harder to quantify but living close to the lake’s northern shores for nearly two years, I witnessed, and on numerous occasions, a strange and yet potentially devastating phenomenon. The winds before a seemingly massive storm would pick up tons of dust, so much so that the approaching wall of dirt would resemble something out of Armagedon! This dust would then seemingly choke the rain clouds and not a drop of water would fall. Normal raindrops are formed by water vapour condensing on particles in the clouds. Excessive dust however, means that the same amount of water vapour is spread across more particles, preventing it from coalescing and forming water droplets. Upon investigation, the signs of excessive over-grazing in the Rift Valley just north of the lake are painfully evident. There are vast tracks of land that are nothing more than massive dust sinks. In fact, the dust is so severe that my 4x4 on occasion even got stuck in nothing but mere dust. This process of desertification is as a result of overgrazing and trampling, inflicted by cattle belonging to the Maasai. This is a complex problem as the Maasai are traditional pastoralists who used to roam from Mount Kenya to southern Tanzania. The tribe has, over the years, been forced into a minute area straddling the border of Kenya and Tanzania and are no longer considered to be nomadic. Adding to this conundrum, the Maasai in the area now have more access to money than in the past through employment at lodges and the soda-ash plant in the nearby town of Magadi. As a result, the Maasai tribesman in the area have probably never had so many livestock as they do today, and certainly never on such a small piece of land. Lake Natron being a large flat and shallow body of water lying close to the equator is susceptible to the minutest decrease in annual rainfall or change in climate. If the thousands of tons of volcanic dust are in fact choking rain clouds, then this will no doubt significantly impact the amount of rainfall reaching the lake. Having viewed this phenomenon on dozens of occasions, I fear that this might indeed be the case.

Another alarming and highly unnecessary threat to the breeding birds, comes in the form of charter pilots flying foreign clients and photographers over the lake, thereby potentially disrupting breeding colonies of birds. Many of these cowboy pilots enter the Tanzanian airspace illegally from the Kenyan side and carry out their aerial acrobatics with ignorance and insensitivity. I have even witnessed a helicopter flying over the breeding birds and when it came to land on the shore, an American lady leapt out exclaiming with glee that when the birds flew off she could even see the eggs!

Lastly, as with so many other ecosystems but none more so than Lake Natron - where the balance between water and evaporation is by nature already delicately critical - Global Warming offers the proverbial ‘nail in the coffin’. The slightest increase in global temperature will desiccate this shallow wilderness potentially taking 75% of the world’s entire Lesser Flamingo population with it!

I believe that while the problems facing the lake are complex, they are not insurmountable. It is not too late for Natron! Placing mining projects and hydroelectric schemes aside, there are a few practical steps that could halt Natron’s demise: The Ewaso N’giro River needs to be better conserved, ensuring that irrigation practices are environment friendly and that designated stable points of the river’s bank are set aside to water livestock, thereby helping limit the excessive silt currently carried in the river. The logjams nearer the swamps must also be removed and replaced with suitable footbridges to allow the river to flow unhindered. The Maasai north of the lake, although no longer nomadic, can be taught rotational grazing techniques and the rehabilitation of currently overgrazed tracts of land should be prioritized. Charter companies, pilots, photographers and tourists alike need to take responsibility, and not fly close to the birds when on route in the area! Lastly, each one of us 6 billion plus human beings, by decreasing our own personal carbon footprints, can help save over 2 million Lesser Flamingoes, by allowing them to continue breeding on Natron’s delicate mudflats.

After my time on the shores of Natron I would like to add the following words to Brown’s repertoire when describing Natron: ‘splendid, isolated, timeless, wilderness, invigorating and surreal’. Might I suggest that Mr Brown would agree had he not risked life and limb to make his wonderful discovery!

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