Why Are Deep Water Currents Important?

Why Are Deep Water Currents Important?
••• péninsule antarctique image by Pollarys from Fotolia.com

Deep water ocean currents are formed when cold, nutrient-rich water sinks and flows away from the surface. There are sources of deep water currents in the northern and southern hemispheres. Deep water currents return nutrients to the surface by a process known as upwelling. Upwelling brings nutrients back into sunlight, where plankton can use the nutrients to provide energy that drives an ocean's ecosystem.

Ocean Layers

Plankton provide food energy that's the basis of a food chain.
••• Moon from deep Ozean image by Stefan Kuhn from Fotolia.com

The oceans consist of layers of water with different qualities. The energy for ecosystems is generated by plankton, mostly in the upper layer known as the photic zone (the region where light penetrates the ocean). Plankton use light and nutrients in the water to generate food energy. Larger organisms feed on the plankton, providing the basis for a food chain or ecosystem that includes invertebrates like shrimp and krill, larger fish, sharks, marine birds and marine mammals. Deeper layers of oceans are colder and dead organisms provide nutrients that fall out of the photic zone into these deeper layers.

Sources

Even the largest whales rely on plankton for food energy.
••• Blue Whale diving for krill off Orange County California image by ADMIRAL BENBOW from Fotolia.com

Deep water currents are formed when surface waters are cooled, become more dense and sink below the surface. Major areas where this occurs are around Antarctica and in the North Atlantic. Water becomes more dense when it has a higher salt content or becomes colder. Both of these processes occur at deep water current sources through a combination of cooling and evaporation.

Nutrient Cycle

Plankton require sunlight and nutrients to produce food energy. Plankton produce most of the food energy in the uppermost layers of the ocean. As this food energy is consumed by larger organisms in the food chain, nutrients are lost as dead organic matter sinks into deeper water. Some of the nutrients are lost forever in ocean sediments, but some of the nutrients are recycled when deep water currents reach surface regions.

Upwelling

Upwelling is a process that causes deep, nutrient-rich waters to rise to the surface where plankton can use the nutrients to produce new food energy. Upwelling can be caused by wind and weather that pushes warm surface waters away from land, causing deeper, nutrient-rich waters to come to the surface. This allows plankton to use the nutrients and the sun's energy to produce new food energy.

Temperature

Deep water currents redistribute cold water from the northern and southern hemispheres back to more temperate regions on Earth. These currents, in combination with warmer surface currents, are sometimes likened to a conveyor belt that moves warm surface waters to the poles and redistributes cold water back toward the Equator. This has the effect of moderating global temperatures.

Related Articles

What Are Deep Currents?
Types of Water Currents
Why Is Hot Water Less Dense Than Cold Water?
What Are Deep Water Currents?
What Are Water Currents?
What Happens Underground During an Earthquake?
How Do Ocean & Wind Currents Affect Weather & Climate?
Four Factors That Create Ocean Currents
How Does Plate Tectonics Affect the Rock Cycle?
What Causes Convection Currents on the Mantle?
Freshwater Biome Abiotic Factors
What Are Surface Currents Caused By?
Density & Temperature of the Lithosphere
How Does Water Affect Weather Patterns?
The Geology of the Earth's Internal Processes
The Effects of Temperature Inversion
What Are Convection Currents?
How Does Salinity Impact Oceans Currents?
Why Is the Uneven Heating of Land and Water Responsible...
Where Does Nearly All of the Earth's Energy in the...