Surprising facts about the rainforests of the ocean
reefs are the rainforests of the ocean – bright spots
of food and shelter in the vast, cold waters of the open sea.
And like the rainforests, reefs have a profound impact on the
overall health and well being of the planet and face serious
threats to their existence.
snorkelers and divers know, coral reefs teem with life. Colorful
fish, turtles, invertebrates and other animals rely on reefs
for food and shelter. They are the most biologically diverse
ecosystems on earth and are home to nearly one quarter of the
world’s marine species.
only do reefs serve as a home for marine life, they also are
critically important to humans. The majority of the total world
population lives in coastal areas and those people depend on
reefs for food, income and protection. Coral reefs provide an
income source through fishing and tourism. In addition, scientists
have discovered that coral communities may contain compounds
that can be manufactured into medicines to treat diseases like
cancer and AIDS. Humans also depend on reefs for protection
from storms and tidal surges.
a thousand coral species currently exist and take fantastic
shapes that resemble mushrooms, moose antlers, cabbages, table
tops, wire strands, fluted pillars and wrinkled brains.
what are they?
animals, vegetables or minerals?
Despite the rock-like or plant-like appearance of corals, they
are animals – tiny creatures that live together in large
are divided into two basic types: hard corals and soft corals.
Hard corals have cup-like skeletons that form the foundations
of coral reefs. Soft corals have bits of bone-like calcium carbonate
scattered throughout their bodies. Coral reefs are formed by
colonies of individual coral animals called polyps that live
together in limestone skeletons. Each polyp is a soft-bodied
invertebrate that resembles an upside-down jellyfish.
corals are animals, they have a symbiotic (mutually beneficial)
relationship with algae that lives inside their tissues. These
algae are known as zooxanthellae. The coral provides a protected
environment for the algae to live in. In return, the algae produce
sugars and other compounds that help nourish the coral. Coral
also gets its color from the zooxanthellae living deep within
the tissues of each polyp. Coral polyps receive about 90 percent
of their food from the zooxanthellae. The other 10 percent of
their food come from capturing plankton.
polyps hunt by extending their tentacles and capturing plankton,
which is microscopic plants and animals that drift on the ocean’s
currents. Corals feed at night because they are less likely
to become victims of predators. During the day, coral polyps
pull in their tentacles and hide deep within their limestone
come in a wide variety of shapes including branching, elkhorn,
mushroom and digitate (finger-like). Different types of coral
have different growth patters, but several factors can affect
the shape a colony takes: where the coral lives, wave action,
light, temperature, the corals’ proximity to each other.
can reproduce either sexually or asexually. During asexual reproduction,
a coral polyp clones itself by forming a new “bud”
next to the parent polyp. The newly formed polyp is an exact
copy of the parent and will remain forever attached to the parent.
Sexual reproduction, also called spawning, takes places when
corals release eggs and sperm into the water to be fertilized.
Fertilized eggs result in coral larvae. Once a larval coral
is formed, it floats on the water’s surface for several
days, sometimes weeks, until it finds a suitable hard surface
on which to attach and start growing.
the Flower Garden Banks National Marine Sanctuary, off the coast
of Texas, mass coral spawning is as predictable as the phases
of the moon. Each summer, eight to 10 nights after the last
full moon of August, between the hours of 9 p.m. and midnight,
the corals in the Flower Garden Banks begin spawning. Each coral
species spawns on a different night to prevent hybridization.
This mass spawning event has been compared to “an upside-down
human activities, including those associated with global warming,
are threatening these rainforests of the ocean and the future
of coral reefs is uncertain. Current estimates note that 10
percent of all coral reefs have been degraded beyond any hope
of recovery. Around 30 percent of coral reefs are in critical
condition and could die within 20 to 30 years. Experts predict
that if current pressures are allowed to continue, 60 percent
of the world’s coral reefs may be completely dead by 2050.
are a number of ways for people to personally help protect coral