Density, Temperature, and Salinity | south-park-episodes.info
2) “Temperature, salinity and density differences in ocean water are the prime causes of ocean water circulation.” Elaborate. ( Words). Some generalizations may also be made about the vertical distribution of ocean temperature, salinity, and density. The most dense water is found o the bottom;. Sea water. Density. • Density of Ocean is determined by temperature, the quantity of dissolved salts (also known as salinity), and the pressure to which a parcel.
The force due to gravity is greater on objects that are more massive, or weigh more. The buoyant force B of water pushes up. In the third century B. He observed that the volume of water pushed out of a tub, or displaced, by an object was equal to the volume of the object.
The buoyant force of the water is equal to the weight of the water displaced.
CC.6 Salinity, Temperature, Pressure, and Water Density
An object accelerates when the forces on that object are unequal. Although acceleration is commonly used to describe an object that is speeding up, the scientific definition of acceleration means changing speed.
An accelerating object can be speeding up or slowing down. An object will always move in the direction of the greater force. An object may accelerate downwards sink or upwards rise in a body of water.
If all of the forces on an object are balanced, there is no acceleration. In this case, the object may not move—like a book sitting on a flat table—or the object may move at a constant speed—like a car traveling at a steady 80 kilometers per hour. In the water, an object might remain still either at the surface or within the water column.
Three cubes of the same size, but with different masses and thus different densities, are placed in three beakers of water Fig.
Because the cubes are identical in volume, they displace the same amount of water. Buoyant force is represented in Fig.
These arrows are the same length for each of the cubes, indicating that the strength of the buoyant force acting on each cube is the same. Because the masses of the cubes are not equal, the gravitational force G acting on each cube is different.
Gravitational force is represented in Fig.
The Ocean and Temperature
As temperature increases, the space between water molecules increases—also known as density, which therefore decreases. If the temperature of water decreases its density increases, but only to a point. Salinity and density share a positive relationship.
As density increases, the amount of salts in the water—also known as salinity, increases.
Various events can contribute to change in the density of seawater. Salinity can decrease from the melting of polar ice or increase from the freezing of polar ice.
Evaporation increases salinity and density while the addition of freshwater decreases salinity and density. The Mississippi delta 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 upwelling. This slightly heavier density is another contributing factor to upwelling as it causes the water molecules to roll over each other.
Salinity is usually 35 ppt parts per thousandbut can range from ppt and is highest in the northern Red Sea. The Red Sea When the temperature, density or salinity of a layer changes rapidly, this region is referred to as a cline. Thermoclines, or areas of rapid change in temperature, familiar to most people who enjoy swimming in the ocean, are the most important due to their effect on planktonic ecosystems and primary producers.
Areas of rapid change in density are pycnoclines and areas of rapid change in salinity are haloclines. Thermoclines occur a short distance offshore when the shallow surface water is heated by the sun, resulting in warm, less dense, water staying at the surface and the sinking of cold, dense water. A seasonal thermocline is formed when surface water is cooled, and sinks to the bottom resulting in a mixing of the layers.
Exploring Our Fluid Earth
The approaching cool weather impacts primary production in the euphotic zone by cooling the surface water and bringing phytoplankton with nutrients to the creatures below. Shorter days and lower angles of sunlight limit the growth rate of the phytoplankton, which in turn limits the primary production and growth rate of organisms higher on the food chain.
The waters turn from blue to green as the increase in the number of phytoplankton dissolving inorganic nutrients causes an increase in chlorophyll biomass. Herbivorous zooplankton biomass also begins to increase, providing food for an entire food web above that depend on the energy they provide. During the summer, the phytoplankton absorb most of the dissolved inorganic nutrients from the surface waters and are consumed by the zooplankton, decreasing the rate of photosynthesis.
Vertical mixing ceases and phytoplankton, which remain in the upper layers, become nutrient-limited. The cycle starts all over in the fall when the surface water cools, churning the deeper, nutrient-rich waters into the depleted surface waters. Nutrients become available again and the phytoplankton blooms in great quantity during the spring after the intense winter mixing.
Fall and summer are the least plentiful months due to the less active summer waters. The seasonal cycle of phytoplankton growth is an amazing demonstration of the complex and interwoven physical, chemical and biological processes of the ocean. Sean Chamberlin has described this phenomenon in the following paragraph: This biological process known as phytoplankton photosynthesis affects a chemical process which is the concentration of inorganic nutrients. As photosynthesis proceeds, the concentration of inorganic nutrients diminishes.
In an ironic twist of fate, the chemical processes the rate at which new inorganic nutrients are made available take over the biological processes rates of photosynthesis.