With reference to the characteristics of the Ocean Currents, consider ...
Characteristics of Ocean Currents:
Ocean currents are continuous movements of ocean water caused by various factors such as wind, temperature, salinity, and density. They play a significant role in regulating global climate and distributing heat around the Earth. Let's analyze each statement given in the question and determine their correctness.
Statement 1: Cold currents are usually observed on the east coast of continents in the low and middle latitudes.
This statement is correct. Cold ocean currents are generally observed on the eastern coastlines of continents in the low and middle latitudes. This is because of the influence of prevailing winds, which blow from east to west in these regions. The winds push the surface water away from the coast, causing upwelling of cold, nutrient-rich water from the depths of the ocean. Some examples of cold ocean currents include the California Current off the west coast of North America and the Benguela Current off the west coast of Africa.
Statement 2: The mixing of warm and cold currents amplifies the growth of plankton.
This statement is incorrect. The mixing of warm and cold ocean currents does not necessarily amplify the growth of plankton. Plankton growth is primarily influenced by nutrient availability, sunlight, and other factors. While upwelling caused by cold currents can bring nutrient-rich water to the surface, the growth of plankton depends on a complex interplay of multiple factors, including temperature, light, and nutrient concentrations. Therefore, the mixing of warm and cold currents alone does not guarantee the amplification of plankton growth.
Statement 3: Oceanic currents are slow at the surface due to friction with the atmospheric air as compared to depths.
This statement is incorrect. Oceanic currents are generally faster at the surface compared to depths. This is because surface currents are primarily driven by wind stress, which directly impacts the upper layers of the ocean. As wind blows over the surface of the ocean, it imparts its momentum to the water, causing it to move in the same direction as the wind. However, as we go deeper into the ocean, the influence of wind decreases, and other factors like density and thermohaline circulation become more dominant in driving the currents. Therefore, oceanic currents are generally slower at greater depths due to reduced wind stress and increased friction with the ocean floor.
In conclusion, the correct statements are:
1. Cold currents are usually observed on the east coast of continents in the low and middle latitudes.
2. The mixing of warm and cold currents does not necessarily amplify the growth of plankton.
With reference to the characteristics of the Ocean Currents, consider ...
Ocean currents are the most important ocean movements because of their influence on the climatology of various regions. Ocean currents are like river flow in oceans. They represent a regular volume of water in a definite path and direction. Ocean currents can also be classified based on temperature: as cold currents and warm currents.
- Cold currents bring cold water into warm water areas. These currents are usually found on the west coast of the continents in the low and middle latitudes (true in both hemispheres) and on the east coast in the higher latitudes in the Northern Hemisphere. Hence statement 1 is not correct.
- Warm currents bring warm water into cold water areas and are usually observed on the east coast of continents in the low and middle latitudes (true in both hemispheres). In the northern hemisphere, they are found on the west coasts of continents in high latitudes.
- Currents are referred to by their “drift”. Usually, the currents are strongest near the surface and may attain speeds over five knots. At depths, currents are generally slow with speeds less than 0.5 knots. We refer to the speed of a current as of its “drift.” Drift is measured in terms of knots. The strength of a current refers to the speed of the current. A fast current is considered strong. A current is usually strongest at the surface and decreases in strength (speed) with depth. Most currents have speeds less than or equal to 5 knots. Hence statement 3 is not correct.
- The mixing of warm and cold currents help to replenish the oxygen and favour the growth of planktons, the primary food for the fish population. The best fishing grounds of the world exist mainly in these mixing zones. Hence statement 2 is correct.