mals, minerals, bacteria, and fungi. While the thousands of different pills, powders, and liquids dispensed by pharmacists today are nearly all synthetic purified chemicals, each designed for a very specific and limited purpose, the roots of the drug industry remain in naturally occurring chemicals.

Pharmaceutical researchers continue to analyze plants and microbes for potential new drugs, but have barely begun to study marine sources, especially bacteria, fungi, and algae. According to W. Fenical and P. R. Jensen's review of the subject in Marine Biotechnology, "On the basis of the few chemical studies reported, and in recognition of the unique compounds that have been isolated, it can be concluded that marine microorganisms could, if effectively explored, represent a major biomedical resource."

It's been discovered, for example, that some of the brightly colored green and purple sulfur bacteria that live symbiotically with sponges and sea squirts produce potent chemicals that can stop viruses in their tracks. A new compound taken from deep-sea bacteria living in sediments more than 300 m (330 yd) below the sea surface inhibits the replication of HIV, the virus that causes AIDS. And still other marine microorganisms are hot tips for new antibiotics, much needed against strains of disease-causing microbes that have developed resistance to known drugs.

Anticancer agents are high on the list of substances being sought by researchers at the Scripps Institute of Oceanography. One of their discoveries is a marine plant adapted for growing in almost saturated brine. It produces a variety of chemicals, including beta-carotene, a possible anticancer agent. Some marine plants in the