Trapped In Time - Chapter 81

Anthropogenic lakes

Anthropogenic lakes are artificially created lakes formed by human activity. They can be the result of intentional damming of rivers and streams or subsequent filling of abandoned excavations by either groundwater, precipitation, or a combination of both.

Meteorite (extraterrestrial impact/ crater) lakes

Meteorite lakes, which are also known as crater lakes, which have been created by catastrophic extraterrestrial impacts by meteorites or asteroids. An examples of meteorite lakes in your countries are Lonar crater lake, India, Lake El’gygytgyn and Pingualuit crater lake, Quebec, Canada, As in case of Lake El’gygytgyn and Pingualuit crater lake, meteorite (extraterrestrial impact/ crater) lakes can contain unique and scientifically valuable sedimentary deposits associated with long records of paleoclimatic changes.

Other different types of lakes in your world are:-

One of the many artificial lakes in Arizona

Lake Parramatta, an artificial lake in Sydney, Australia

A naturalized former gravel pit lake in northern Croatia

The crater lake of Volcán Irazú, Costa Rica

These kettle lakes in Alaska were formed by a retreating glacier

Ephemeral ‘Lake Badwater’, a lake only noted after heavy winter and spring rainfall, Badwater Basin, Death Valley National Park

Ice Melting on Lake Balaton

In addition to the mode of origin, lakes have been named and classified in various other ways according to their thermal stratification, salinity, relative seasonal permanence, degree of outflow, and other factors. Also, different cultures and regions of the world have their popular nomenclature.

Types of lakes according to thermal stratification

In addition to their origin, there are various other ways of either naming or defining types of lakes. One major way of classification lakes in on the basis of thermal stratification because it is a major control on animal and plant life inhabiting a lake and the fate and distribution of dissolved and suspended material in a lake. For example, the thermal stratification and the degree and frequency of mixing exerts a strong control on the distribution of oxygen within it. In addition, the lake can be classified according to important factors such as seasonal variations in lake volume and level, oxygen saturation, and salinity of its water mass. Finally, the names of types of lakes that are used by the lay public and in the scientific for different types of lakes are often informally derived from either from their morphology of other aspects of their physical characteristics.

F.A. Forel was the first scientist to classify lakes according to their thermal stratification. His system of classification was later modified and improved upon by Hutchinson and Laffler. Because the density of water varies with temperature, with a maximum at +4 DC, thermal stratification is an important physical characteristic of lakes that controls the fauna and flora, sedimentation, chemistry, and other aspects of individual lakes. First, the colder, heavier water typically forms a layer near the bottom, which called the hypolimnion. Second, normally overlying it is a transition zone known as the metalimnion. Finally, overlying the metalimnion is a surface layer of a warmer, lighter water is called the epilimnion. However, this typical stratification sequence can vary widely depending either on the specific lake, the time of the season, or combination of both.

Based upon thermal stratification, lakes are classified as either holomictic lakes or meromictic lakes.

A meromictic lake is a lake which has layers of water which do not intermix. The deepest layer of water in such a lake does not contain any dissolved oxygen. In addition, the layers of sediment at the bottom of a meromictic lake remain relatively undisturbed because there are no living aerobic organisms. The lack of disturbance allows for the development of lacustrine varves.

A Holomictic lake is a lake that has a uniform temperature and density from top to bottom at a specific time during the year. This uniformity temperature and density allow the lake waters to completely mix. Holomictic lakes are non-meromictic lakes. Based upon thermal stratification and frequency of turnover, holomictic lakes are divided into amictic lakes, cold monomictic lakes, dimictic lakes, warm monomictic lakes, polymictic lakes, and oligomictic lakes. The classification of lakes by thermal stratification presupposes lakes with sufficient depth to form a hypolimnion. As a result, very shallow lakes are excluded from this classification system.

The stratification in a lake is not always the result of variation to density because of thermal gradients. Stratification within a lake can also be the result of differences in density resulting from gradients in salinity. In case of a difference in salinity, the hypolimnion and epilimnion are separated not by a thermocline but by a halocline, which is sometimes referred to as a chemocline.

Types of lakes according to seasonal variation of lake level and volume

Lakes are informally classified and named according to the seasonal variation in their lake level and volume. Some of the names include:

The ephemeral lake is a short-lived lake or pond. If it fills with water and dries up (disappears) seasonally it is known as an intermittent lake.

The dry lake is a popular name for an ephemeral lake that contains water only intermediately at irregular and infrequent intervals.

The perennial lake is a lake that has water in its basin throughout the year and is not subject to extreme fluctuations in level.

Playa lake is a typically shallow, intermittent lake that covers or occupies a playa either in wet seasons or in especially wet years but subsequently drying up in an arid or semiarid region.

Vlei is a name used in South Africa for a shallow lake which varies considerably in level with the seasons.

Types of lakes according to water chemistry

Lakes are also informally classified and named according to the general chemistry of their water mass. Some of the types of lakes include:

An acid lake is a lake that has a pH is below neutral (<6.5). A lake is considered highly acidic when the pH drops below 5.5, below which when biological consequences occur. Such lakes include acid pit lakes occupying abandoned mines and excavations; naturally acid lakes of igneous and metamorphic landscapes; peat bogs in northern regions; acid-saline lakes of arid environments; crater lakes of active and dormant volcanoes; and lakes acidified by acid rain.

A salt lake, which also known as a brine lake, is an inland body of water situated in an arid or semiarid region, having no outlet to the sea, and containing a high concentration of dissolved salts (principally sodium chloride). Examples include the Great Salt Lake in Utah and the Dead Sea situated between Israel, Jordan and West Bank.