8 Questions
What is the net result of wind blowing across the surface of the water and the Coriolis Effect?
Transportation of a layer of water 90 degrees to the direction of the wind
What drives the slow circulation of water at great depths?
Density differences
Thermohaline circulation is driven by density differences caused by temperature and salinity in water.
True
What is the density range of sea water due to the presence of salts and other substances?
1.027 to 1.028 gm/cm^3
What are the three major factors that affect sea water density?
Temperature, Salinity, Pressure
Greater salinity leads to lower sea water density.
False
In deep layers of sea water, lower temperature leads to higher ___________.
density
Match the layers of sea water density with their descriptions:
Surface Layer = Density lower due to thermal expansion Deep Layer = Contains 80% volume of sea water with higher density Pycnocline Layer = Depth of 300 - 1000 m, boundary separating different density layers
Study Notes
Relationship between Densities
- Density of sea water indicates the mass per unit volume, usually in grams per cubic meter (g/cm³)
- Density of distilled water at 4°C is 1.00 g/cm³, while sea water density ranges from 1.027 to 1.028 g/cm³, 2-3% higher due to salts and other substances
- A substance will float or sink based on its density, with less dense substances floating upwards and denser ones sinking
- Vertical circulation on a large scale changes sea water density
Factors Affecting Sea Water Density
- Temperature: density of sea water changes with temperature, with warmer water being less dense and colder water being more dense
- Energy of water molecules increases with heat, leading to thermal expansion and lower density
- Cold water has a higher density due to molecules being closer together
- Salinity: positive relationship between sea water density and salinity, with higher salinity leading to higher density
- Pressure: directly related to sea water density, with high pressure leading to increased density due to closer packing of water molecules
Vertical Distribution of Sea Water Density
- Three distinctive layers of sea water density:
- Surface Layer (2% of sea water volume, 100-200m deep): lower density due to thermal expansion
- Deep Layer (80% of sea water volume, 100m-4000m deep): higher density due to lower temperature
- Pycnocline Layer (18% of sea water volume, 300-1000m deep): boundary between two liquid layers of different densities, with a rapid change in density with depth
Upwelling and Sinking
- Upwelling: process in which cold water from the bottom comes to the surface, rich in nutrients
- Sinking: process in which surface water moves to the bottom, often due to convergence of surface waters
- Ekman Transport: responsible for upwelling and sinking, where surface water moves parallel to the wind direction, and wind-driven ocean circulation
Significance of Upwelling and Sinking
- Upwelling:
- Provides nutrients for phytoplankton growth, supporting marine food webs
- Supports large fisheries in upwelling regions
- Influences weather, contributing to fog banks and cool summers
- Sinking:
- Supplies dissolved gases and nutrients to deeper ocean regions
- Affects biological productivity in the surface layer
- No direct effect on climate
This quiz covers the study material for CSIR Earth Sciences Physical Oceanography. It includes questions on various topics related to ocean sciences and physical oceanography.
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