The Pacific coast of Mexico extends from 14° to 33°N, and from 92° to 117°W.
This includes the Baja California Peninsula, the second largest in the world (about
1,600 km in length), numerous islands and the eastern coast of the Gulf of California; the Gulf of Tehuantepec, making a total coast line well above 8,000 km in
length (Fig. 2.1).
The Gulf of California (GC) has several oceanographic features that make it
unique among semi enclosed seas of similar latitude and dimensions, the most
important being strong tidal mixing, some of it close to the deep stratified oxygen
concentration zone. The GC is 1,400 km long and its width in the inner region is
150–200 km, with an area of 177,000 km
2 , a mean depth of 818 m, and a volume
of 145,000 km
3 . The GC is an evaporative basin, but in general it gains heat
through the surface. Lacking a sill at the point of connection with the Pacific
Ocean, the GC is constantly affected by a wide spectrum of signals coming from
the Pacific Ocean, including tides and El Niño, which is the most important
interannual anomaly (Lavin and Marinone 2003) (Fig. 2.1).
The Revillagigedo Archipelago or Revillagigedo Islands are a group of four
volcanic islands off the Mexican Pacific coast, known for their unique ecosystem.
They have been part of the Mexican State of Colima since 1861, but are under
Mexican federal jurisdiction. They lie 386 km southwest of Cabo San Lucas, the
southern tip of Baja California and between 720 and 970 km west of Manzanillo.
They are located around 18°49
0 N and 112°46
0 W. The Revillagigedo Islands are
home to many endemic plant and animal species and often are called Mexico’s
‘‘little Galapagos’’. They are recognized as a distinct terrestrial ecoregion, part of
the Neotropic ecozone. Socorro Island is the largest and has the most diverse flora,
fauna, and topography (Fig. 2.1).
The Gulf of Mexico (GM) consists of several ecological and geological provinces, such as the continental shelf, the continental slope, and the abyssal plain.
The coastal zone consists of tidal marshes, sandy beaches, mangrove-covered
areas, and many bays, estuaries, and lagoons. The continental shelf forms an
almost continuous terrace around the margin of the GM. Its width varies from a
maximum of more than 320 km to a minimum of about 40 km. Off the coast of
Campeche and the Yucatan Peninsula, the continental shelf consists of a broad
area composed primarily of carbonate material. Off the states of Campeche and
Yucatan, the bank of Campeche extends from 198 and 238 N, and 898 and 938W in
the southern GM (Gore 1992). It is delimited in the north by the Campeche slope;
in the south by the shoreline of the states of Campeche, Yucatan and Quintana
Roo; in the west by the Campeche canyon; and in the east by the Yucatan strait.
This area is an almost flat carbonate plateau that has an average depth of about
51 m (Fig. 2.1).
The remainder of the GM shelf consists of sand, silt, and clay sediments. On the
shelf and the slope that dips downward to the abyssal plain, buried salt domes
occur at various depths. The abyssal plain, which forms the floor of the gulf,
consists of a large triangular area near the centre, bounded by abrupt fault scarps
toward Florida and the Yucatan Peninsula and by more gentle slopes to the north
2 The Echinoderms of Mexico
13
This includes the Baja California Peninsula, the second largest in the world (about
1,600 km in length), numerous islands and the eastern coast of the Gulf of California; the Gulf of Tehuantepec, making a total coast line well above 8,000 km in
length (Fig. 2.1).
The Gulf of California (GC) has several oceanographic features that make it
unique among semi enclosed seas of similar latitude and dimensions, the most
important being strong tidal mixing, some of it close to the deep stratified oxygen
concentration zone. The GC is 1,400 km long and its width in the inner region is
150–200 km, with an area of 177,000 km
2 , a mean depth of 818 m, and a volume
of 145,000 km
3 . The GC is an evaporative basin, but in general it gains heat
through the surface. Lacking a sill at the point of connection with the Pacific
Ocean, the GC is constantly affected by a wide spectrum of signals coming from
the Pacific Ocean, including tides and El Niño, which is the most important
interannual anomaly (Lavin and Marinone 2003) (Fig. 2.1).
The Revillagigedo Archipelago or Revillagigedo Islands are a group of four
volcanic islands off the Mexican Pacific coast, known for their unique ecosystem.
They have been part of the Mexican State of Colima since 1861, but are under
Mexican federal jurisdiction. They lie 386 km southwest of Cabo San Lucas, the
southern tip of Baja California and between 720 and 970 km west of Manzanillo.
They are located around 18°49
0 N and 112°46
0 W. The Revillagigedo Islands are
home to many endemic plant and animal species and often are called Mexico’s
‘‘little Galapagos’’. They are recognized as a distinct terrestrial ecoregion, part of
the Neotropic ecozone. Socorro Island is the largest and has the most diverse flora,
fauna, and topography (Fig. 2.1).
The Gulf of Mexico (GM) consists of several ecological and geological provinces, such as the continental shelf, the continental slope, and the abyssal plain.
The coastal zone consists of tidal marshes, sandy beaches, mangrove-covered
areas, and many bays, estuaries, and lagoons. The continental shelf forms an
almost continuous terrace around the margin of the GM. Its width varies from a
maximum of more than 320 km to a minimum of about 40 km. Off the coast of
Campeche and the Yucatan Peninsula, the continental shelf consists of a broad
area composed primarily of carbonate material. Off the states of Campeche and
Yucatan, the bank of Campeche extends from 198 and 238 N, and 898 and 938W in
the southern GM (Gore 1992). It is delimited in the north by the Campeche slope;
in the south by the shoreline of the states of Campeche, Yucatan and Quintana
Roo; in the west by the Campeche canyon; and in the east by the Yucatan strait.
This area is an almost flat carbonate plateau that has an average depth of about
51 m (Fig. 2.1).
The remainder of the GM shelf consists of sand, silt, and clay sediments. On the
shelf and the slope that dips downward to the abyssal plain, buried salt domes
occur at various depths. The abyssal plain, which forms the floor of the gulf,
consists of a large triangular area near the centre, bounded by abrupt fault scarps
toward Florida and the Yucatan Peninsula and by more gentle slopes to the north
2 The Echinoderms of Mexico
13