Jodi N. Harney
jharney@soest.hawaii.edu
Ph.D. Student, Coastal Geology Group
Dept. of Geology & Geophysics, University of Hawaii

Algae is a common sight in tropical and temperate oceans, particularly in shallow, well-lit waters close to shore. Algae may be single-celled (like cyanobacteria) or hundreds of feet long (like the kelp forests off California). They are grouped into classes - red, brown, and green algae - with different characteristics. There are both "good" and "bad" species of algae in the shallow, nearshore marine environment in Hawaii. Some species are indicators of high nutrient content in the water, usually a sign of pollution, especially along developed coastlines. Many types of algae are inhabitants of coral reefs whose abundance are kept in check by grazing fish, molluscs, and other animals. Some algae can calcify, secreting skeletons composed of calcium carbonate. "Coralline" (red) algae are so named because they bear such resemblance to corals in their encrusting, calcareous appearance. Both coralline algae and the calcareous green alga Halimeda are significant producers of sediment in shallow waters around the Hawaiian Islands. Only a few types of algae found on Hawaiian reefs are shown here. Contributions and suggestions are welcome.



CLASS RHODOPHYTA (Red algae)

Order Corallinales (Coralline algae)

Porolithon gardineri	Porolithon onkodes
(branching)	(encrusting)

Non-calcareous (fleshy) red algae

Amansia	Botryocladia	Galaxaura

Liagora	Pterocladia

CLASS PHAEOPHYTA (Brown algae)

Dictyota	Laurencia	Sargassum

CLASS CHLOROPHYTA (Green algae)

Halimeda opuntia	Halimeda discoidea	Neomeris

Cladophoropsis	Microdictyon	Ulva fasciata

CLASS CYANOPHYTA (Blue-green algae or cyanobacteria)

Lyngbya

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