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Gulf
of California
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Marine
Discovery focuses on marine biology and conservation of
the Gulf of California, also known as the Sea of Cortez.
The Gulf of California is the closest ocean to Tucson, only
a four-hour drive away (160 miles). The University of Arizona
has been actively involved with the Gulf of California for
thirty years; graduate students and professors have published
a large body of research on the Gulf and undergraduates
take frequent field trips to CEDO. The Gulf of California
has some very special environments and many species of organisms
found nowhere else on earth. Some interesting facts are
listed below. |
- The Gulf
of California is approximately 1,500 km long and 160 km wide.
It has mixed semi-diurnal tides and one of the greatest tidal
ranges on earth. The difference between the highest tide and
lowest tide covers up to 2 miles horizontally and as much
as 9 meters vertically in the northern gulf. The Gulf of California
is one of the youngest ocean bodies, probably having been
formed by the separation of the North American Plate and the
Pacific Plate by plate tectonic movement.
- The Gulf
of California is generally studied as two regions: the northern
gulf and the southern gulf, with the border between the two
near Guaymas. The northern portion of the gulf is shallow
(up to 200 m deep) due to a large amount of siltation from
Colorado River run-off. The northern gulf has many endemic
species including populations of the vaquita (the endangered
harbor porpoise) and the totoaba (a large endangered fish).
Because the Colorado River once flowed into the Gulf, but
now rarely does, many changes are occuring in the estuarine
environment at the far northern end. The sedimentation and
changes in the environment brought on by the loss of the inflow
from the Colorado River both favor the isolation of species
and their consequent speciation.
- The Southern
basin is much deeper, and includes the Guaymas trench, which
is approximately 2000 m deep. The trench has volcanic and
hydrothermal vents, which support biotic communities based
on hydrogen sulfide for energy, rather than sunlight. Tidal
ranges are not as great in the southern Gulf, making the northern
basin better for studying the intertidal zone. The S. Gulf
is similar to the marine environment south of the Gulf; many
of the species seen in the Pacific Ocean have made their way
into the Gulf of California.
- Throughout
the Gulf, winds and tidal action cause upwelling. The large
amount of sunlight, combined with the nutrients provided by
upwelling, allow high primary productivity throughout the
Gulf. The high primary productivity supports numerous invertebrates,
fish and large marine mammals, including the awesome fin whale!
Pods of dolphins and orcas are seen regularly, and the migration
of elephant seals into the Gulf of California is currently
being studied. Ed Ricketts (Between the Tides), John
Steinbeck (Log from the Sea of Cortez), Richard Brusca
(Common Intertidal Invertebrates of the Northern Gulf of
California) and Donald A. Thomson (Reef Fishes of the
Sea of Cortez) are just a few of the people who have written
about the richness and diversity of the Sea of Cortez.
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