Page 123 - (DK) Ocean - The Definitive Visual Guide

ESTUARIES AND LAGOONS 121

ATLANTIC OCEAN EAST eastern end, it connects to the Atlantic
via a narrow artificial channel, the
Ebrié Lagoon Vridi Canal, opened in 1951. Abidjan,
the largest city in Ivory Coast, stands
TYPE on several converging peninsulas and
Coastal lagoon of
variable salinity islands in an eastern part of the lagoon;
other communities situated on or in
AREA
200 square miles the lagoon include the town of Dabou
(520 square km) and the village of Tiagba (see below).
The Komoé River provides the main
LOCATION West of Abidjan, Ivory Coast, West Africa input of fresh water. In winter the
lagoon becomes salty, but it turns to
The Ebrié Lagoon is one of three fresh water during the summer rainy
long, narrow lagoons that line the season. Levels of pollution in the lagoon
shores of the West African state of have been high for some years due to INDIAN OCEAN NORTH VEMBANAD LAKE
Ivory Coast. With a length of 62 miles dumping of refuse and discharge of Vembanad, the largest Kerala coastal lagoon,
(120 km) and an average width of untreated industrial effluents and Kerala Backwaters is listed as a Wetland of International
2/2 miles (4 km), it is the largest sewage from the nearby urban areas. Importance under the Ramsar Convention.
1
lagoon in West TYPE Chain of coastal
Africa. Its average saltwater lagoons shielded from the sea by low barrier
depth is 16 ft AREA Approximately islands and spits that formed across the
(5 m). Near its 400 square miles mouths of the many rivers flowing
(1,000 square km)
down from the surrounding hills.
During the summer monsoon rains,
TIAGBA VILLAGE
In the village of LOCATION Southeast of Cochin, Kerala State, the lagoons overflow and discharge
southwestern India
Tiagba, on the sediments into the sea, but toward the
outskirts of a small end of the rains, the seawater rushes
island in the Ebrié The backwaters of Kerala in southern in, altering salinity levels. The aquatic
Lagoon, the buildings India are a labyrinth of lagoons and life in the backwaters, which includes
are raised up on small lakes, linked by 900 miles crabs, frogs, otters, and turtles, is well
wooden piles. (1,500 km) of canals. The lagoons are adapted to this seasonal variation.

PELICANS IN
LAKES AND LAGOON
In this satellite view, the Coorong Lagoon DECLINE
is the narrow blue strip behind the yellow
sand dunes. Above are the lakes The Coorong is home to a large
Alexandrina (left) and Albert (right). breeding colony of Australian
Pelicans, which inhabit a string of
islands in the center of the
lagoon. Since the 1980s, however,
their numbers have fallen
significantly due to reduced flows
of fresh water into the Coorong
from the Murray River. The
resultant higher salt levels in the
lagoon have reduced the growth
of an aquatic weed that
is a major part of the food chain.

INDIAN OCEAN SOUTHEAST to ducks, cranes, ibis, terns, geese, and and the Coorong can receive both AUSTRALIAN PELICANS
This pelican, one of seven species worldwide,
waders such as sandpipers and stilts. fresh and salty water. The lagoon was is widespread in Australia, where it lives on
Coorong Lagoon The lagoon is separated from the once freely connected to the lake, from freshwater, brackish, and saltwater wetlands.
Great Australian Bight (considered which it received a much larger supply
TYPE part of the Indian Ocean) by the of fresh water. In 1940, however,
Saltwater coastal lagoon Younghusband Peninsula, a narrow barrages were built between the lagoon lagoon. There is ample evidence that
AREA spit of land covered by sand dunes and and the lake to prevent seawater from this has adversely affected the lagoon’s
80 square miles scrubby vegetation. The lagoon is reaching the lake and the lower reaches ecosystem. In particular, several species
(200 square km) OCEAN ENVIRONMENTS
about 93 miles (150 km) long, with a of the Murray River. The salinity of of plants have become less abundant
width that varies from 3 miles (5 km) the lagoon’s waters increases naturally or disappeared, many fish species have
LOCATION Southeast of Adelaide on the southeastern to just 330 ft (100 m). At its with distance from the sea due to declined, and migratory bird numbers
coast of South Australia northwestern end, the lagoon meets evaporative losses. However, reduced have fallen. Further, the reduced flow
the outflow from Australia’s largest water flows from the Murray, due to a from the Murray may result in the
The Coorong Lagoon is a wetland river, the Murray, after the river has combination of barrage construction eventual closure of the channel joining
that lies close to the coast of South passed through Lake Alexandrina. In and extraction of water for irrigation the lagoon to the ocean, which would
Australia. It is famous as a haven for this region, called the Murray Mouth, projects, has caused a gradual further prevent migration of fish and other
birds, ranging from swans and pelicans both river and lagoon meet the sea, increase in salinity throughout the animals between the two.