Page 110 - (DK) Ocean - The Definitive Visual Guide

108 COASTS AND THE SEASHORE

ATLANTIC OCEAN WEST ATLANTIC OCEAN SOUTHWEST
Pink Sands Beach Copacabana Beach

TYPE Dissipative beach, TYPE Embayed,
protected by reefs dissipative beach
COMPOSITION Sand COMPOSITION White
mixed with broken shells sand
and skeletons
1
LENGTH 2 / 2 miles (4 km)
LENGTH 2.5 miles (4 km)
LOCATION Harbour Island, off Eleuthera, northeast LOCATION Rio de Janeiro, southeastern Brazil
of Nassau, Northern Bahamas
One of the most famous beaches in
Pink Sands in the Bahamas is a the world, Copacabana Beach is a
gently sloping beach that faces wide, gently curving stretch of sand
east onto the Atlantic Ocean. It is between two headlands. Behind the
protected from ocean currents by beach lies the city of Rio de Janeiro,
an outlying reef. The pale pink color with green, luxuriant hills in the
of the sand comes from small, single- hinterland. The beach is crowded
celled organisms called foraminiferans, much of the year and is known for its
in particular, the species Homotrema beach sports and New Year’s Eve
rubrum, also known as the sea firework displays. The sea area off the
strawberry. The shells of these beach is not always recommended for
organisms are bright red or pink due swimming, due to strong currents.
to the presence of an iron salt. In parts
of the Bahamas they are abundant,
living on the underside of reefs. When
they die, they fall to the seafloor,
where they are broken by wave action
and mixed with other debris, such
as the white shells of snails and sea
urchins, as well as mineral grains.
This mixture is then finely pulverized
and washed up on the shore as
pink-colored sand by wave action.

GENTLE SLOPE
Pink Sands is an example of a dissipative
beach, on which waves break some distance
from the shore, then slowly roll in, dissipating
their energy across a broad surf zone. COPACABANA LOOKING NORTH

St. Ninian’s Isle in the Shetland Isles typically projects at right angles to the forms a tombolo may come from the
ATLANTIC OCEAN NORTHEAST
provides a classic example of a coast and has a beach on each side. mainland, the island, the sea floor, or a
St. Ninian’s Tombolo tombolo, or ayre—a short spit of St. Ninian’s Tombolo has been in combination. Scientists have deduced
sedimentary material that connects existence for at least 1,000 years, and that a tombolo will usually form
TYPE an island to a nearby land mass or its permanence may be due to a when the island’s distance from the
Tombolo mainland. A tombolo is formed by cobble base underlying the sand. This shore is less than two-thirds of its length
COMPOSITION waves curving around the back of an tombolo tends to become lower and parallel to the shore (the distance of St.
Yellow and white sand island so that they deposit sediment narrower during storms as a result of Ninian’s Isle from the shore is only
LENGTH on a neighboring land mass, at the destructive wave action, while during about one third of its length). In other
1 / 2 mile (700 m)
point directly opposite the island. calmer weather the waves build it up cases, a feature called a salient may
LOCATION West coast of southern Mainland, the Over time, these sediments gradually again with sand carried from offshore form—a sand spit that extends toward
main island of the Shetland Isles, off Scotland, UK build up into a tombolo, which or the nearshore. The sediment that the island but does not quite reach it.

OCEAN ENVIRONMENTS NARROW CONNECTION

A slim, sandy tombolo extends from
the Shetland island of Mainland in the
foreground, to St. Ninian’s Isle.