Bottom Water Temperature

The temperature of water is a physical attribute that expresses how hot or cold it is. Because hot and cold are arbitrary concepts, temperature can also be defined as a measurement of a substance’s average thermal energy 5. Because thermal energy is the kinetic energy of atoms and molecules, temperature is the average kinetic energy of atoms and molecules. 5. Heat is a form of energy that may be transmitted between substances. 

Oceanology

Bottom water is near the ocean floor in oceanology. It differs significantly from the top layer in terms of oxygen content, salinity, bulk temperature (characteristic temperature), and thus density. The Antarctic Bottom Water is the source of the majority of bottom water in the Pacific, Indian and Atlantic Oceans, as well as areas of the North Atlantic. Bottom waters flow relatively slowly, driven mostly by slope topography and temperature and salinity differences, especially when contrasted to wind-driven surface ocean currents. Because of the topography of the Arctic Ocean floor and the adjacent Arctic shelf, the bottom water of the Arctic Ocean is more isolated.

Estuaries

Bottom water in a river estuary draining into a saline body demonstrates unusual mud transfer. Because of the estuary’s intermixing of fresh and saltwater, a horizontal isohels gradient is formed, with lower salinity levels upstream, resulting in the upstream flow of bottom water. As the river’s current and turbulence decrease, mud particles begin to settle. When the particles reach the floor, they are carried back to the estuary’s head, where they collect until the salinity of the surface and bottom waters becomes comparable and the bottom flow declines. At this point, the procedure produces a distinct pile of mud. 

Lake Hydrograph

Lake bottom water may have low amounts of oxygen, even to the point of no dissolved oxygen (i.e., anaerobic), as well as significant levels of chlorinity and organic-induced acidity. Summer heating and winter cooling in many lakes, particularly in continental climate zones, create large vertical temperature gradients that impede water intermixing, resulting in summer and winter thermal lake stratification. Bottom water overturning occurs in fall (autumn overturn) and spring (spring overturn) due to temperature gradient equalisation and the subsequent easier intermixing by wind and other causes of turbulence.

Factors affecting water temperature

Many environmental factors can influence water temperature. Sunlight/solar radiation, heat transmission from the atmosphere, stream confluence, and turbidity are examples of these elements. These elements have a greater influence on shallow and surface waters than on deep water 

Sunlight affects water temperature

Solar radiation has the most impact on water temperature. The most significant source of heat transmission to water temperature is sunlight. Sunlight, often known as solar radiation, is a type of thermal energy. This energy is subsequently transported to the surface of the water as heat, raising the temperature of the water. As a result, the temperature of the water varies daily depending on the quantity of sunlight it receives. Sunlight will only transmit heat via the photic zone if a body of water is deep enough to stratify (light-reaching). The majority of this energy (more than half) is absorbed in the first two metres of water. This energy will be absorbed at an exponential rate until the light is gone. The depth of the photic zone varies, but it can reach up to 200 m in the oceans. 

Atmosphere\scold air over warm water makes fog

When cooler air travels over warmer water, rivers might appear to steam in the winter. Photographer: Anthony DeLorenzo/Flickr At the water’s surface, atmospheric heat transfer occurs. Because heat always travels from a higher to a lower temperature, this transfer can occur in both directions. 6. When the air is cold, warm water transfers energy to it, causing it to cool. This conduction is frequently observed as fog or a “steaming” river. If the air is warm, cold water will absorb the heat and warm up. 

Turbidity increases water temperature

Monitoring turbidity during the Passaic River dredging project. Turbidity can raise the temperature of water. Increased turbidity raises the temperature of the water. The amount of suspended particulates in water is measured as turbidity. These suspended particles absorb solar radiation heat more effectively than water 47. The heat is subsequently transferred from the particles to the surrounding water molecules, raising the temperature 47.

Confluence\river lake temperature

The temperature of the lake might change as the river flows into it. Photographer: Roberto Groundwater, streams, and rivers have the ability to change the temperature of the bodies of water into which they flow. If a spring or groundwater source is colder than the river into which it flows, the river will cool. Using heat transfer principles (energy flows from hot to cold), the river loses energy to the cooler water as it heats it 6. If the inflow is high or quick enough, the water’s equilibrium temperature will be near to the inflow temperature. 

Man-made Influences\thermal pollution increases water temperature

Thermal pollution caused by municipal and industrial effluents can have a negative impact on water quality. Vmenkov’s photo is courtesy of Wikimedia Commons. Groundwater, streams, and rivers have the ability to change the temperature of the bodies of water into which they flow. If a spring or groundwater source is colder than the river into which it flows, the river will cool. Using heat transfer principles (energy moves from hot to cold), the river loses energy to cooler water. Man-made effects on water temperature include thermal pollution, runoff, deforestation and impoundments. 

Pollution from Heat

Thermal pollution is defined as any discharge that significantly alters the temperature of a natural water source 48.  This pollution is frequently caused by municipal or industrial effluents. 1. If the discharge temperature is much higher than the natural water temperature, it might have a negative impact on water quality. Groundwater, streams, and rivers have the ability to change the temperature of the bodies of water into which they flow. If a spring or groundwater source is colder than the river into which it flows, the river will cool. Using heat transfer principles (energy travels from hot to cold), the river loses energy to the cooler water. Thermal pollution has a number of serious repercussions, including decreased dissolved oxygen levels, fish mortality, and invasive species influxes. 

Deforestation

Water temperature can be influenced by factors other than man-made additions. Water that is shaded by vegetation and other things will not absorb as much heat as water that is exposed to the sun 14. A body of water can become extremely warm when trees or riparian canopies are removed, changing its natural cycle and ecosystems 

Dams, for example, can have a significant impact on water temperature cycles. While a dam does not directly add heat to the water, it can have an impact on the natural patterns of water temperature warming and cooling. 9. A working dam without a sliding gate assembly can change the temperature of the water downstream, affecting local fish population behaviours. 

Conclusion

This article briefly explained about water temperature and terms associated with it. Also it gave a brief overview about the factors affecting it. Water’s temperature can be changed by the transfer of heat by sources like air, thermal pollution, sunlight, another water source.

Bottom water is the lowest water mass in a body of water, defined by its bottom, and has distinct physics, chemistry and ecology features.