Mighty Waters Week: Day #5

Greetings,

We hope that you have been enjoying this amazing heatwave that all of the UK is experiencing! What have you been up to on these lovely summer days picnics? because we have been enjoying our precious sunbathing minutes. For those of you who do not know it is Mighty Waters Week and in the  spirit of this week and this heatwave we just wanted to remind you that it is so, so important to stay HYDRATED! to make this clear we are not talking about a coke (though we know how tempting one of those are on a hot day) but with actual water. In order to avoid scary things like heat stroke or you know DEATH! keep hydrated.  

Anyways, today’s post isn't about keeping hydrated it is in fact one of the sources of all our bottled water freshwater lakes, why we hear you say? Because when thinking about any type of freshwater system we found that lakes isn’t really the first or second thought in your mind and we hope to change that. So here it goes…

Lets begin with the worlds largest lake shall we? well there’s a problem with that the worlds largest lake is actually saline it is in fact the Caspian Sea… no we didn’t get that wrong, it’s one of those things in science that doesn’t make sense (as there are many) the Caspian Sea is actually a lake not a sea. A lake. And so we rephrase the question to… what is the worlds largest freshwater lake? This title is owned by none other than Lake Superior, how aptly named. Lake Superior is part of the great lakes of North America forming the biggest continuous mass of freshwater on Earth.

Lake Superior covers an area larger then the UK!

Just a few lakes that support amazing wildlife:

Lake Victoria is located in east central Africa along the equator,  it supports 350 species of fish, some of which are thought to be unique to this lake. Many of these fish come from the Cichlid family. 

This is just 1 member of the Cichlid family

As seen by Lake Victoria, Lakes hold the ability to cater to many marine life, and these can be often deadly members of the oceanic world. Lake Nicaragua in Central America is home to one of the worlds deadliest sharks, this lake is home to the big bad bull shark. Bull sharks are known for its temper and aggression, it is also the only specie of its kind that is able to tolerate the changes in salinity from salt-fresh. 

Did you know that it was the Bull Shark that may have been the true inspiration behind the movie hit JAWS.

 Lakes may support a great diversity of animals but other than the nature that they have lakes have plenty of other characteristics that make them amazing, take Lake Tanganyika and Lake Malawi they both have a distinctive feature called a thermocline. A thermocline is a  200m permanent barrier separating the warmer water from the colder water and preventing any mixture of oxygen and nutrients thus creating what is called a bottom dead zone. In Lake Malawi little is able to survive in the dead zone apart from the larvae of a lake fly, these ingeneous creatures have adapted to remain in the oxygen deprived region (the dead zone) in the day thus avoiding predators and once the night takes over they spawn towards the surface.

Interestingly both these lakes are smaller than the one previously mentioned, Lake Tanganyika is 33,000sq km and Lake Malawi is 30,000sq km, thought they are smaller they have been found to harbor a greater diversity of fish, as a cause of the species richness that both Lakes contain they are often seen as diving hotspots!

The Mother Of All Lakes:

The picture above is showing the oldest lake in the world from space. This lake is between 25-30 million years old. This is the Lake Baikal. At Biobunch we love to celebrate the natural marvels of the world whether they be big or small, when reading more about this lake we were amazed at the beauty and the diversity so we were buzzing to share it with you guys to. The lake Baikal is in eastern Siberia and there it is known as the sacred sea it holds a fifth of the our planets surface water. Similar to the stories of other lakes such as that of Tanganyika the Baikal is only where it is due to the movements of  tectonic plates. 

We don’t need to tell you about the severity of a Siberian winter, needless to say, it is harsh with winter temperatures averaging -20 degrees, this plummeting temperature causes the lake to freeze over for more than 5 months. At this point, two ton trucks exploit this 1.2 m thick continuous ice sheet by using it as a highway. 

Underneath this thick layer of ice lies the definition of a winter wonderland, ice sculptures pierce the water and life is found in profusion. The Baikal is isolated and as such this ancient beauty has experienced evolutionary explosions!! It now contains 1200 species of animals, 1000 species of plants, all of which 80% are found nowhere else. Many of the animals found in this lake resemble marine creatures which is strange for a lake (in other words salt water creatures ). Amongst this vast diversification there are 225 species of amphipods that call this lake home, and they play a very important role in maintaining the hygiene of the lake. Baikal proudly holds 40% of the worlds amphipods which resemble shrimp and can often be as big as mice they scavenge on the dead in conditions that decomposition bacteria even find hard to function properly in.

A Freshwater seal...you bluffing:

These seals are smaller than most other seals they grow to 1.2-1.4m in length.

We bluff you not introducing the worlds only freshwater seal! And they happen to only call the Baikal home (just another reason why Lakes are awesome). The Nerpa were  thought to have migrated to the lake 22 million years ago from the Arctic Ocean along rivers that went extinct ages ago. The population is stable at around 50,000. 

Females give birth during the winter in ice lairs. In order to breath they must maintain breathing holes in the ice and they do this by scraping the edges with sharp claws or by gnawing at the ice, as spring finally arrives the ice starts to melt causing the pups to become increasingly exposed to wandering bears and even the odd crow.  

These protruding ice segements from the ice lairs for the Nerpa go give birth in.

 Adult Nerpa like all other seal are amazing divers, they dive down 300m and can remain underwater for at least 70 minutes at a time. The diet constitutes mainly of an oily fish that is only found in Lake Baikal called Golomyanka seriously this is a real thing, they contain about 35% oil and are one of the most commonest fish in the lake. These fish are amazing they are able to cope with the bone breaking pressure 1400m down and if taken out they literally melt (don’t try it though poor strange looking things). 

Two pretty awesome discoveries were made on this lake. One of them was that unlike Lake Tanganyika and Malawi that has a thermocline to sepreate the oxygen out form the bottom layer, Lake Baikal’s water is constantly being mixed meaning that oxygen is always plentiful right at the bottom which means that there are possibly even more animals that have not been spotted yet at the very depths of Lake Baikal. Number two was that at 400m down scientists were amazed to find hydrothermal vents! As you may or may not know these vents are only thought to exist in the deep oceans. Thriving around this vents are small communities of sponges, bacterial mats , snails, fish and even transparent shrimps. 

And that marks the end of this post, if you are interested there are new extreme wildlife expeditions that are being offered to explore the Lake Baikal, we aren't one for the cold but we caught ourselves even considering it... what about you are you tempted to brave a Siberian winter and what would you bring with you? (it should be ok you would only need a really, really big coat and gloves... right?) 

BioBunch.

Over and out.