Page 65 - Oceans

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≤ Beach life
Most of the animals that live on sandy beaches
and tidal mudflats are burrowing clams and
≤ tiDe pools worms, which use tubes and tentacles to gather
On rocky shores, the receding tide often leaves pools of water among the rocks. food from the water at high tide. There may be
When this happens high on the shore, the pools heat up and may dry out, but pools millions of them, but when the tide goes out they
that form below midtide level are not exposed to the Sun for so long, so they stay retreat into their burrows and are hidden from
cool. They make ideal refuges for marine life that cannot survive being left high and view. The shorebirds that feed at low tide know
dry for several hours, and the biggest tide pools may even contain large fish. their hiding places, however, and are experts at
digging them out.

COASTAL PLANTS

ROCKY CLIFFS SALT MARSHES MANGROVES SEAGRASS MEADOWS
In the splash zone above the level of In cooler regions, the upper shores The tropical equivalent of a salt marsh Seagrasses are the only flowering plants
high spring tides, the shore is colonized of sheltered river estuaries are overrun is a mangrove swamp—a forest of that live underwater. They grow on sandy
by flowering plants such as thrift. These by low-growing plants such as sea salt-tolerant trees that are specially seabeds in sheltered, shallow water, in
maritime plants can tolerate being lavender and cord grass. These plants are adapted to grow in tidal mud. They tidal estuaries, and coral reef lagoons.
drenched in salt spray, which would kill unusual because they can survive being have modified roots that rise above the They are an important source of food for
most species. This enables them to spread flooded by salt water at high tide. Each mud to absorb oxygen from the air. The sea turtles, the strange “sea cows” known
over large areas of the shore where other plant species has a different tolerance roots also trap mud suspended in the as dugongs, and—at low tide—grazing
plants cannot grow. Although the soil to this, so they grow in well marked water, enabling mangroves to spread birds such as geese. Seagrass meadows
is usually very shallow and poor, they zones above midtide level. They form along coasts. They provide habitats for also provide vital refuge for small fish,
can often flourish in the few pockets broad, muddy salt marshes, which are a variety of animals from baby fish such as this seahorse, as well as the
of fertile earth that build up in crevices important refuges and feeding sites for to crocodiles, besides forming natural young of bigger fish that live in deeper
and on rocky cliff ledges. shorebirds and other animals. barriers to storm waves. water as adults.