How geographical position impacts life in the Savannah

SCIENTISTS say big lakes such as Victoria join hands with other bigger water bodies on earth such as Pacific, Atlantic and Indian Ocean to make 361.132 square kilometres which occupy about 70.08 per cent of the total area of planet earth.

With about 1.3 billion cubic kilometres of water, streams, rivers, lakes, seas and oceans play a big of preserving water in liquid form for longer period than any parts in and around the planet Earth.

Scientists estimate before evaporating into the sky one litre of water spend more than 3,200 years moving from one part to another inside large water bodies such as Pacific, Atlantic and Indian ocean but this period lasts up to more than 20,000 years in Antarctic and Arctic.

While depending on supply from different streams and rivers, big lakes such as Victoria, Tanganyika and Nyasa are capable of preserving one litre of water for a period which lasts between 50 to 100 years before it is discharged into the sea through big rivers such Nile which empty its content into Mediterranean Sea.

Unlike streams and rivers such as Wami, Ruaha and Rufiji which pass under forest canopies, the rate of evaporation on big water bodies such Victoria is bigger because of most of its surface is exposed to sunrays from the sky.

Scientists say hot sunrays hit water on the surface of a lake and heat its molecules into a boiling point where they are transformed into vapours which through a process called evaporation escape into the sky where they form rainy clouds.

Scientists say rain are droplets of water falling from the atmosphere after condensation process has taken place.

When water vapour rises, it cools at high altitude until dew point is reached.

Dew point is the temperature at which the atmosphere is saturated with water vapour.

Condensation takes pales after dew point has been reached to from water droplets.

These droplets combine to form larger drops which fall as Sun.

There are three types of rainfall which are convectional rainfall, relief or orographic rain and cyclonic rain.

Meanwhile, scientists say different factors affect this process but the number of molecules and good amount of oxygen in a single drop of water on the surface of a water body play an important role in evaporation on big lake such as Victoria.

Scientists say Lake Victoria receive its supply through convectional rainfall which is formed through vertical of moist air currents.

Here convectional currents rise due to differential heating of the earth’s surface. Covering more than 69,484 square kilometres, Lake Victoria is surrounded by Uganda, Kenya and Tanzania which occupies 49 per cent or 33,700 square kilometres of the total water body.

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Lake Victoria has Kagera River which supplies about 6.4 billion cubic metres of water a year.

Scientists say the inflow from Kagera River is about 28 per cent of the lake’s outflow which makes Lake Victoria to be a unique water body in the world where it is considered to be the second largest freshwater lake by surface area.

In terms of volume, Lake Victoria is the world’s ninth largest continental lake, containing about 2,750 cubic kilometres of water.

Scientists say most lakes lie in the Northern Hemisphere at higher latitudes, the average annual temperature in the Northern Hemisphere is15.2 Celsius while in the Southern Hemisphere is 13.3 Celsius, Lake Victoria is found in the middle part of these two parts of the world where the Equator line divides it into two parts.

The equator is one of the five notable circles of latitude on Earth, the other four are the two polar circles which also known as the Arctic Circle and the Antarctic Circle and the two tropical circles which are the Tropic of Cancer and the Tropic of Capricorn.

The equator is the only line of latitude, which is also a great circle, scientists from different perspective say it is the one whose plane passes through the centre of the globe.

Scientists say the equatorial plane runs through the Sun twice a year on equinoxes in March and September.

Locations on the equator experience the shortest sunrises and sunsets because the Sun’s daily path is nearly perpendicular to the horizon for most of the year, this makes the length of daylight to be almost constant throughout the year.

At the same time when rate of fresh air that enter into a water body become bigger it accelerates the rate of evaporation on the surface of a lake or ocean, while gravitation force which upon molecules may bring down the rate of evaporation on the surface water.

At a long process of the big hydrological cycle, the evaporation stage plays a crucial role to purify water before sending it to the sky where it stay in form of clouds before it turns into rain which nourish lives of animals, birds, insects and vegetation on the Earth.

With these facts in their minds, scientists say the average annual temperature in the Equator is 31 Celsius which impact the weather on the surface of the lake, covering more than 69,484 square kilometres with average annual temperature of 23 Celsius on the surface.

This impact weather on the surface of the lake and in the area around this biggest water body in Africa.

Scientists define rain as is liquid water in the form of droplets that have condensed from atmospheric water vapour and then precipitated that is, become heavy enough to fall under gravity.

Scientists say Lake Victoria receives 80 per cent of its water from direct rainfall, this is true because the average evaporation on the lake is between 2.0 and 2.2 metres per year which is almost double the precipitation of the whole area that is exposed to the direct sunrays.

Meanwhile Enyangala is the name for Agama lizards among the Waikuzu of Bunda while Sukuma people of Mwanza and Shinyanga call these fast-moving lizards Zare.

Unlike the Sukuma, in Mara the Wanata, Waikoma and Wangureme people of Serengeti believe that the red headed agama lizard has magical power of deterring thunder and lightning from striking them.

Scientists say it’s the male agama lizard who have bright colours which they use to attract female during breeding season.

Agama Lizards are active in early hours break at noon and come out in the afternoon hours because they can’t tolerate high temperatures, so to see them please observe their schedules.

Every day there are hundreds if not thousands of these lizards roaming on rocks standing around Lake Victoria. Agama Lizards may be easily recognised by their nodding and speedy running habit, but they have incisor-like front teeth designed for quick cutting and chewing of their prey.

Like Chameleons the teeth of Agama Lizard are on the outer rim of the mouth instead of inner jaws like other species of Lizards. Generally, they feed on insects, flowers grass, berries, seeds and even the eggs of smaller lizards and other smaller species too.

With a long tail, Agama Lizard has body size of 12.5 to 30 cm with strong legs capable of running very fast into hidings whenever they are caught in open areas.

During breeding seasons male nod their head rhythmically and change their body appearance from brown to different bright colours to attract female for a courtship.

They normally change into bright orange and dark shining blue colours which make female to fake a sexual arouse by turning their hind part toward male who will chase them until catch and mount them.

At this point sometime male will node their head vigorously, chase and fight each other by using their long tails as weapons until losers are pushed away from territories.

Males claim an area as a territory whereby other mature males are not allowed in, but juveniles and six or more females may stay with him in the same location.

Although it’s not common but during hutching female may fight or chase an intruding fellow in order to protect her eggs. Agama Lizard are sometime called Dragon Lizard and there found in different species such as Agama aculeata, Agama agama and Agama lionotus.

At the same time scientists say about 20 per cent of all amounts of water that is available on the earth accumulate on the Aquifer, this is an underground storage which receive water through infiltration on porous underground rock and accumulate one big area.

The upper part of an Aquifer is called water table as scientists say the precious liquid may be stored into this underground storage for a period which lasts between 100 to 10,000 years before coming out through underground stream and springs.

After a rain season, good amount of rainwater accumulates on valleys, flood plains and other wetlands which become source of water for different animals in different parts in and around Mount Kilimanjaro national park.

Scientists estimate that all these reservoirs may store water for a period which lasts for more than three months while providing water for animals in Mkomazi national park at the time when there is no rain.

Through the same process of hydrological cycle, water from these storages allow water to go through evaporation and escape into sky as vapour while between 1 per cent and 0.5 per cent all surface water is used by different plants through their roots.

During dry season through a process called transpiration plants allow 99 per cent of water which go into the sky in the form of vapour from stomata which their numbers on a leaf affect the rate of evaporation from that particular plant.

Temperature also affects the rate of evaporation from a leaf because during dry season stomata are opened frequently forcing different vegetation in a hector inside Mkomazi national park to lose about 11,400 litres of vapour a day while large trees lose 151,000 litres or 40,000 gallons of vapour in a year.

Speed and rate of hydrological cycle on big water bodies is fast and large because of shape and numbers of molecules in water on the surface of a lake, sea and ocean is good for attaining boiling point without the presence of fire.

Different scientific research indicates that the presence of salty vapour in the air accelerate the rate of evaporation from a water body and enable the water vapour to hang on the sky where they are condensed to form a cloud.

The cloud is formed from nuclei which are obtained during condensation whereby droplets are combined together to form a frosty cloud that hangs in troposphere zone with different width according to their position in the sky.

The troposphere zone occupies more than 75 per cent of the atmosphere and accumulates about 99 per cent of all amounts of vapour in the sky and it is the major source of natural forces which affect the weather on the planet because it from this zone where water is turned back to earth.

It is from this zone where droplets are formed from vapour before embarking into another long and complex journey to the earth, this is what scientists call Precipitation which happens when the weight of droplets on the sky become unbearable due to gravitational force from the ground.

During precipitation a droplet with a circumference measuring up 3.01 millimetres is pulled down at the top speed of 8 metres per seconds, before reaching the ground their size is reduced to 0.5 millimetre although during heavy downpour some escape with 2.0 and 2.5 millimetres to affects leaves of different vegetation on the ground.

The rate of rainfall in one area also affects growth of vegetation in different area and influence lives of humans and animals in the wild whereby different species of primate prefer tropical forests while most felids dwell in the savannah.