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Mzima Springs: Clear waters and the impact of hippos

Mzima Springs stands out as one of the most remarkable topographical features within the Tsavo Conservation Area, offering a compelling destination for visitors exploring Tsavo West National Park.

The allure of Mzima Springs lies in its crystal-clear waters, providing a unique opportunity for observers to witness hippos and Nile crocodiles in their undisturbed natural habitat.

The crystal clear water of Mzima springs is the outcome of a geological filtration process occurring 50 kilometres north of the springs, in the Chyulu Hills.

Geological Filtration: Origins in the Chyulu Hills

The Chyulu Hills is a mountain range constituting a 100-kilometer-long volcanic field. It is characterized by substrate composed of volcanic rock and ash. Volcanic activity started 1.5 million years ago but the area is still considered active, with two eruptions occurring in 1856.

Rather than flowing on the surface, water percolates through the porous soil. Undergoing a natural filtration and purification process as it flows underground. Remarkably, the water can remain subterranean for up to 25 years, gradually journeying southward, before resurfacing as the pristine waters of Mzima Springs, located 50 kilometres away.

Spanning a length of 2 kilometres, the springs create multiple natural pools and ponds that serve as habitats for hippos and Nile crocodiles, as well as multiple other bird, reptile and mammal species.

This flow continues until the water encounters a solidified lava flow, forcing it underground once again.

The springs, due to their relative isolation from other water sources, play a crucial role as a keystone in the surrounding ecosystem, attracting numerous animals that rely on its clear waters for sustenance.

Ecological Chain: Hippo Dung as a Catalyst

Notably, the hippos inhabiting the springs contribute significantly to the ecosystem dynamics. Acting as nutrient transporters from the land into the springs, their nocturnal grazing habits, where they can consume up to 40 kg of grass in a single night, followed by continuous excretion into the water, profoundly shape the ecosystem surrounding Mzima Springs.

Hippo dung, ceremoniously sprayed in the water and surrounding environment, serves as a crucial fertiliser for algae and microbes while also providing sustenance for scavenger fish. These microorganisms, in a cascading sequence, become a food source for invertebrates, subsequently attracting insectivorous fish.

This intricate ecological chain, initiated by the hippos’ nutrient contribution, leads to the emergence of various bird species. Bee-eaters and herons, among others, engage in hunting fish and insects. Additionally, crocodiles rely on the fish that are dependent on the dung of the hippos.

The transparency of the water provides researchers with a distinctive perspective on the behavioural patterns and social interactions of the aquatic inhabitants. The springs were featured in the 2003 Survival Special “Mzima: Haunt of the Riverhorse,” which presented the first documented hippo infanticide.

Ecosystem Challenge: The Impact of the 2009 Drought

The importance of the springs on the surrounding ecosystem was brutally brought to attention in the year 2009, where a prolonged drought had devastating impacts on the Mzima springs wildlife.

Starving game animals migrated in large numbers to the permanent water sources of Mzima Springs, leading to competition with the resident hippos. The once lush grassland surrounding the spring transformed into a desert, resulting in hippos succumbing to starvation. By September 2009, the hippo population had dwindled to just five, a stark decrease from the 70 recorded in 2003.

Presently, Mzima Springs remains a thriving and picturesque watercourse, pulsing with vibrant life. Visitors have the opportunity to stroll along its banks and, uniquely, venture into an underwater viewing tank. This submerged vantage point allows a rare glimpse of hippos, crocodiles, and fish in their underwater habitat, an experience seldom found elsewhere.

This enduring beauty is a testament to the geological legacy of a volcanic formation dating back 1.5 million years, coupled with water’s 25-year journey through volcanic soil. Thanks to this harmonious blend of nature and geological processes, both animals and humans can enjoy the crystal clear water of Mzima springs

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