The
California Current is a
Pacific OceanThe Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Tepre Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan. It extends from the Arctic in the north to Antarctica in the south, bounded by Asia and...
currentAn ocean current is a continuous, directed movement of ocean water generated by the forces acting upon the water, such as the wind, Coriolis force, temperature and salinity differences and tides caused by the gravitational pull of the Moon and the Sun...
that moves south along the western coast of
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
, beginning off southern
British ColumbiaBritish Columbia is the westernmost of Canada's provinces and is famed for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . In 1871, it became the sixth province of Canada.The capital of British Columbia is Victoria, the 15th largest metropolitan region in Canada...
, and ending off southern
Baja CaliforniaBaja California is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises the northern half of the Baja California peninsula, north...
. It is a type of current known as an Eastern boundary current and is part of the North Pacific Gyre, a large swirling current that occupies the northern basin of the Pacific. The movement of northern waters southward makes the
coastThe coast is defined as where the land meets the sea. A precise line that can be called a coastline cannot be determined due to the process of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
al waters cooler than the coastal areas of comparable
latitudeLatitude, usually denoted by the Greek letter phi gives the location of a place on Earth north or south of the equator. Lines of Latitude are the imaginary horizontal lines shown running east-to-west on maps that run either north or south of the equator...
on the east coast of the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
The
California Current is a
Pacific OceanThe Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Tepre Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan. It extends from the Arctic in the north to Antarctica in the south, bounded by Asia and...
currentAn ocean current is a continuous, directed movement of ocean water generated by the forces acting upon the water, such as the wind, Coriolis force, temperature and salinity differences and tides caused by the gravitational pull of the Moon and the Sun...
that moves south along the western coast of
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
, beginning off southern
British ColumbiaBritish Columbia is the westernmost of Canada's provinces and is famed for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . In 1871, it became the sixth province of Canada.The capital of British Columbia is Victoria, the 15th largest metropolitan region in Canada...
, and ending off southern
Baja CaliforniaBaja California is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises the northern half of the Baja California peninsula, north...
. It is a type of current known as an Eastern boundary current and is part of the North Pacific Gyre, a large swirling current that occupies the northern basin of the Pacific. The movement of northern waters southward makes the
coastThe coast is defined as where the land meets the sea. A precise line that can be called a coastline cannot be determined due to the process of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
al waters cooler than the coastal areas of comparable
latitudeLatitude, usually denoted by the Greek letter phi gives the location of a place on Earth north or south of the equator. Lines of Latitude are the imaginary horizontal lines shown running east-to-west on maps that run either north or south of the equator...
on the east coast of the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Additionally, extensive
upwellingAn Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water...
of colder sub-surface waters occurs, caused by the prevailing northwesterly winds acting through the Ekman Effect. The winds drive surface water to the right of the wind flow, that is offshore, which draws water up from below to replace it. The upwelling further cools the already cool California Current. This is the mechanism which produces California's characteristic coastal
fogFog is a cloud that is in contact with the ground. A cloud may be considered partly fog; for example, the part of a cloud that is suspended in the air above the ground is not considered fog, whereas the part of the cloud that comes in contact with higher ground is considered fog...
.
The cold water is highly productive due to the
upwellingAn Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water...
, which brings to the surface nutrient-rich sediments, supporting large populations of
whaleWhale is the common name for marine mammals of the order Cetacea. The term whale is sometimes used to refer to all cetaceans, but in more common English usage it generally excludes the members of the Delphinoidea superfamily, such as dolphins and porpoises...
s,
seabirdSeabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s and important fisheries. A narrower, weaker counter current, the
Davidson CurrentIn oceanography, the Davidson Current is a coastal countercurrent of the Pacific Ocean running north along the western coast of the United States from Baja California Mexico to northern California to at least latitude 40°N. It prevails during the winter months, generally from September through...
, occasionally moves somewhat warmer water northwards during the winter months. During El Niño events, the California Current is disrupted, leading to declines in
phytoplanktonPhytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτον , or "plant", and πλαγκτος , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
, resulting in cascading effects up the food chain, such as declines in fisheries, seabird breeding failures and marine mammal mortality. In 2005, a failure in the otherwise predictable upwelling events, unassociated with El Niño, caused a collapse in
krillKrill is a type of shrimp-like marine invertebrate animal. These small crustaceans are important organisms of the zooplankton, particularly as food for baleen whales, manta rays, whale sharks, crabeater seals, and other seals, and a few seabird species that feed almost exclusively on them. Another...
in the current, leading to similar effects.
Further Information
For information on legal statutes and regulations of the California Current Large Marine Ecosystem, see
http://www.cclme.org.