2) “Temperature, salinity and density differences in ocean water are the prime causes of ocean water circulation.” Elaborate.

Topic: Salient features of World’s Physical Geography

2) “Temperature, salinity and density differences in ocean water are the prime causes of ocean water circulation.”  Elaborate. (200 Words)

NCERT

  • Words: ~225

    The deep ocean, devoid of wind, was assumed to be perfectly static by early oceanographers. However, it has been found with modern instrumentation that movement in deep water masses is frequent. In contrast to the wind over land, the major driving forces of ocean currents are differences in density and temperature.

    Circumstances of ocean water circulation:

    Role of Density: The ocean water is constantly churning underneath, bringing nutrients up to the top. The difference in density of cold water versus density of warmer water is responsible for ocean currents and up-welling. Warm seawater floats and cold (4°C ), dense (1 g/cm3), seawater sinks, so ocean temperatures also vary across the surface and into the depths.

    Role of Salinity: Seawater is saturated with salts at 35 ppt and at 4°C the salinity causes the density to actually be 1.0278 g/cm3. This slightly heavier density is another contributing factor to up-welling as it causes the water molecules to roll over each other.

    Role of Temperature: Temperatures range from -2°C to 28°C in most cases, but are hotter near hydro-thermal vents or closer to land. Salinity is usually 35 ppt (parts per thousand), but can range from 28-41 ppt and is highest in the northern Red Sea.

    Thus, density, temperature and salinity provides for shuffling of layers which tries to balance into their most stable positions provides a driving force for ocean water circulation.

    • Joseph Stalin

      Friend I am Impressed
      Well structured , Neatly explained and best summed Up.
      I wish i could too remember the Value upto 3 decimal places 😀

      • Its easy, we can remember mobile numbers.

      • naren

        joseph .whenever u get time review my answer . I follow your guidance and today I wrote three answer of ques 1 ,2 ,8 .

    • Madhu Babu

      good

    • naren

      well answer with very impressive data .

    • waytoias

      nice answer…btw don’t u think we should give some examples of the ocean current based on the given reasons….

  • Guest

    temperature ,Density and Salinity all are related to each other and
    causes water to circulate vertically ,they are the initiator of movement of
    water , This along with other factors like wind direction, Coriolis force
    ,orientation of land and ocean boundary and gravity causes water to flow in
    horizontal direction and causes ocean currents.

    Temperature is the prime force for movement of water .

    Warm water is lighter and floats
    over the cool water and causes vertical flow or mixing . when water is warmed it expand and creates a void
    in which cold and nutrient rich water from bottom of the ocean fills up.

    Ocean water near the equator receives more insolation and expands up
    to a level around 8 cm above the mean sea level creating a gradient by which water
    flows from the equatorial region to pole wards as major surface currents. On
    the other hand cold water from the polar regions sing below the warm surface
    water and upwells to fill up the vacancy
    near the equator.

    Density and salinity is inter related . Water with higher salinity
    have higher density and the vice-versa . water with higher density in heavier and
    sinks to the bottom .this not only causes the vertical mixing ,with temperature
    difference between the latitudes causing
    change in density in the surface level ,water from denser region flows to the less
    dense regions causing horizontal flow.

  • The Imp

    temperature ,Density and Salinity all are related to each other and
    causes water to circulate ,they are the initiator of movement of water , This
    along with other factors like wind direction, Coriolis force ,orientation of
    land and ocean boundary and gravity causes water to flow in horizontal
    direction and causes ocean currents.

    Temperature is the prime force for movement of water .

    Warm water is lighter and floats
    over the cool water and causes vertical flow or mixing . when water is warmed it expand and creates a void
    in which cold and nutrient rich water from bottom of the ocean fills up.

    Ocean water near the equator receives more insolation and expands up
    to a level around 8 cm above the mean sea level creating a gradient by which water
    flows from the equatorial region to pole wards as major surface currents. On
    the other hand cold water from the polar regions sing below the warm surface
    water and upwells to fill up the vacancy
    near the equator.

    Density and salinity is inter related . Water with higher salinity
    have higher density and the vice-versa . water with higher density in heavier and
    sinks to the bottom .this not only causes the vertical mixing ,with temperature
    difference between the latitudes causing
    change in density in the surface level ,water from denser region flows to the less
    dense regions causing horizontal flow.

    • VictimOfIas

      simple and good answer

      • The Imp

        Thanks …

  • Ravinder Singh

    Ocean water circulations has a major impact on the climatic and
    socio-economic conditions of a country. These circulations are
    episodic and zonal and are caused due to following factors:-

    Temperature: Oceanic currents moves from higher temperature
    to the lower temperature if other things remains constant. But if
    increase in temperature causes increase in evaporation then
    displacement shall take place from low temperature(where evaporation
    is less) zone to high temperature zone.

    Salinity: Higher density causes the oceanic water to sink
    and therefore displacement starts from low saline area towards the
    higher saline zone.

    Density: Difference in density drives the oceanic current as
    a higher density zone tends to subdued therfore current moves from
    lower densuty zone to higher density zone.

    Apart from these factors precipitation, pressure, and rotation of
    earth also plays prominent role in driving these currents and any
    change in any of the above factors can lead to disasterous
    consequences.

    • prateek

      Good

      • Ravinder Singh

        thanks….keep reviewing

  • Anit ifs

    Ocean circulation is depedent on a host of factors in which temperature, salinity and density differnces are the major ones.

    The temperature of the oceans is regulated by a continual churning of the waters. mainly it’s the surface water that flows with speeds in drifts averaging 5knots. North atlantic drift for example carries warm waters to the western Europe and raises the temperature of the waters there by atleast a degree. The lower levels beyond the thermocline are mostly constant in temperature near 0 degrees and water flow is slow in these areas.

    Salinity is dependent on the amount of evaporation of water. This in turn depends on the insulation received, the amount of fresh water that comes in the area and the winds flowing in the area. Water would flow from areas of high salinity to that of high salinity. Thus fresh waters from ice melts in artic readily mixes with the surrounding oceans.

    The movement of earth creates a buldge in the equatorial areas and water flows down the slight incline of 8cm towards poles. The water at poles is colder and thus denser than the water from the equator, and thus sinks below the warmer incoming waters. This also creates clockwise currents in northern hemisphere and opposite in southern. This system is further affected by phenomenons like monsoon, flow of winds and temperature anomalies.

    • Alok Singh

      Water would flow from areas of high salinity to that of high salinity

      pls clarify.

      • Anit ifs

        Low salinity…. my mistake

  • Aish

    The important components in ocean water circulation is temperature and salinity which directly controls the density and density is an important governing factor for the vertical movement of the ocean waters. The trio factors role in ocean water circulation are :
    -> The temperature of the surface of the ocean is fixed by heat exchange.Heat is transferred from low to high latitudes by winds in the atmosphere and surface currents in the ocean. The infrared radiation heat loss is constant with the latitude which means that the water is much warmer in the tropical regions.But the main mechanism to transfer heat to deeper layers of the ocean is through turbulent mixing of wind and waves and this is known as mixed surface layer.The vertical distribution of temperature on the deep ocean is controlled by density driven movements of water.

    -> The salinity of ocean water is a usually the balance between evaporation and precipitation i.e,. it excludes the salt from vapor. Salinity along with temperature determines the density of ocean water and hence its vertical flow patterns which determine the thermohaline circulation.

    -> Density varies depending upon the salinity and temperature. The surface layer of the ocean is less dense as compared to the bottom.It gets more dense due to drop in temperature and concentration in salinity.The ocean circulation in depths is horizontal that is the water moves along the layers with same density.

    Therefore salinity,temperature and density are important in thermohaline circulation.

  • Sneha Goley

    guys, please review thanks

    • rahul

      It would better if you provide some examples of ocean water circulations e.g .North Atlantic cold current etc.

      • Sneha Goley

        thanks, I will surely add examples 🙂

  • naren

    The oceans are not a single , homogenous body of water . They actually consist of a number of distinct water masses due to variation in temperature , salinity and pressure . Temperature , salinity ,pressure differences helps in ocean water circulation such as

    – changes in salinity , temperature and pressure causes differences in density resulting in the layering we sea in water .

    -vertical circulation in the ocean is usually the result of surface density .

    -density will increase with decreasing temperature . increasing salinity and increasing pressure or depth , at the depth Coriolis force is not more effective results deep sea water not move easily .

    -the denser water will sink , or downwell and the lighter water will rise , moon attract more easily light water results more high tide occurs .

    -if salinity is high ocean water movement by winds is difficult .

    -if temperature is high ocean water move easily by winds such Mediterranean sea water are more warm move faster .
    Please review friends

  • shanky

    Ocean water moves between latitudes having impact on the climatic and socio-economic conditions of the countries like warm water moves from equator towards poles and in turn cold water from poles to equator.The prime causes of ocean water circulation are:
    1.Temperature difference : High temperature creates low pressure at sea which lead to in crease in the sea level and force the water to move towards low sea level.Therefore water moves from high temperature to low temperature for example equator to sub tropical high.
    2.Salinity difference: Ocean water is saline and salinity varies over the ocean horizontally as well as vertically.Low salinity makes water less dense and increase the sea level which lead to movement of water towards high saline water with low sea level.
    3.Density difference: More the water is dense less is the sea level and difference in the density creates difference in the sea level which lead to movement of water from high density to low density.
    pressure belts,planetary winds are also responsible for the ocean currents .

    plz review my ans.
    thank you.

  • Bhanu Saurabh

    The Ocean that seems unstable at the surface is equally churning at the bottom. The surface unrest is due to planetary winds, moon’s gravity and pressure belt over it but the lower disturbance is due to several other reasons, few of them are:
    1. Temperature: The high temperature heats up the water and evaporates them which causes a low pressure belt over it; forcing winds to rush in, dragging cold water from surrounding high pressure zones. To fill in the temporary vacuum the deep down cold water rises in the high pressure zone, thus dragging water from Deep Ocean of low pressure zone, thus creating a convection belt.
    2. Salinity: The salinity of water is the result various causes including rivers deposits and anthropogenic causes. Salinity makes the water denser and heavier which sinks it to the bottom forcing an upwelling of lesser saline water.
    3. Density: The density of water is a composite effect of temperature and salinity. Water is denser in low temperature and high salinity. The greater the density the heavier is the water. This again pushes the denser water down and upwelling of less denser water takes place.
    Indeed the movements of high depth water of ocean bring about stability in the Oceans near poles by taking warmer water from equatorial Indian Ocean, which also affects the climate. We call this current as “The Global Conveyor Belt”.

  • Roshan Tiwari

    Guys plz review:
    ————————
    Density is the prime mover for the ocean water. Density is affected by Temperature and Salinity of the Ocean water hence all three are main factors in movement of ocean water.

    Effect of Temperature:
    Increase in temperature decreases the density and this less dense water move towards high density ocean water as surface current while high density water sinks and moved as subsurface water and completes the cycle like water from equatorial region moves towards high latitudes.

    Effect of Salinity:
    Salinity increases then density also increases which again moved as mentioned above e.g. water from Atlantic ocean moves towards Mediterranean sea because salinity of Mediterranean sea is much higher than adjoining Atlantic Ocean.Same is the case when ocean water from Red Sea moves toward Arabian Sea via Babel Man deb strait.Salinity of Baltic sea decreases due to freshwater mixing from rives and density decrease and then this water moves toward Northern Sea and subsurface current moves towards Baltic Sea.

    Effect of Density:
    Water moves from low density to high density as in case of polar water where density is decreased by melting ice and then it moves towards lower water as cold surface currents.

  • Ajitesh89

    The circulation of oceanic water originate due to the combined effect of several factors acting internally as well as externally. Temperature, salinity and density difference are the internal factor that is present in ocean.

    >– Temperature Difference

    There are two way motion of water, that is, one of surface water and other of sub-surface water. Due to higher temperature at equatorial region, the density of surface water is low. While the density of water in polar region is high. Hence the surface water flow from the equatorial to polar region. On the other hand, the sub-surface water move from polar to equatorial region in order to balance the loss of water.

    >– Salinity Difference

    Salinity increases the density of water. Hence oceanic water will flow from the more saline water to the less saline water when the temperature of the regions are same. For example, the current flow from the Atlantic ocean to Mediterranean sea via Gibralter strait is caused due to salinity difference.

    >– Density Difference

    As we know that the water move from the low density to higher density. In addition to the temperature and salinity, fresh water influx due to melting of glaciers also change the density. This addition of fresh water decrease the density of water. East Greenland cold current is supposed to be caused by this reason.

    Hence the oceanic water circulation depends on the factors such as temperature, Salinity and density. One should consider these factors together and not separately.