Dr.
Kenneth Norris
"By the
way naturalists are definitely not extinct. People in my field
keep realizing, sometimes with a kind of surprise, that eye-to-eye
contact with nature is the truest of experiences and the simplest
way to understand." 
Butterflyfish
© Copyright Keoki
Stender | |
Using species
diversity as a measure, Coral Reefs and Tropical Rain Forests are the two most
successful types of ecosystems in the world. This is especially surprising for
coral reefs, since they are generally found in tropical, nutrient poor waters
(this lack of nutrients is what makes the water so clear and blue). The reef is
based on a "mutualistic symbiotic" relationship between an animal that looks
like a tiny sea anemone or somewhat like a flower (the coral) and a microscopic
photosynthetic alga that lives within the tissue of the coral (the zooxanthellae). (Learn more about corals and watch the polyps grow.)
This
association is called a "mutualistic symbiosis" because
both organisms benefit from the arrangement. The microscopic alga
lives inside the coral, where it is protected, providing the coral
with the nutrients it makes with the help of sunlight (photosynthesis).
Many of the animals that live in and on the reef live off the coral,
either directly by eating the coral or indirectly by eating the
coral feeders or their parasites. Other animals feed on macro algae
that grow on top of the dead coral and other substrates. (Learn
more about the ecology of Hawaiian
coral reefs.)
A coral reef,
just like a tropical rain forest, has a highly complex architecture, with many
nooks and crannies. It provides places to hide and substrate to attach to for
algae and a wide variety of invertebrates, such as sponges, anemones, worms,
snails, octopus, crabs, lobsters, urchins, sea stars, and tunicates. These
animals, in addition to the coral polyps and the algae, in turn provide a wide
array of food sources for the reef fish. As a result, coral reef fish have
evolved into a dazzling array of species in response to the extensive variety of
food sources and types of shelter. The diversity of coral reefs is clearly seen
in the species richness of its fish. Of all the marine fish species throughout
the world, between 66 and 89% inhabit coral reefs (6500-8700 species in total). |
