Letters from the August 21, 2004, issue of Science News

Complex issue

When cyanobacteria and plants transfer electrons photosynthetically, light is absorbed not by their photosynthetic proteins but by chlorophylls (“Protein Power: Solar cell produces electricity from spinach and bacterial proteins,” SN: 6/5/04, p. 355: Protein Power: Solar cell produces electricity from spinach and bacterial proteins). Some of these proteins indeed participate in electron flow, but they are not plant photoreceptors. How then, do they “retain their function” and “absorb photons” in the fabricated solar cell described?

Cleon Ross
Victor, Idaho

The materials that the scientists were referring to as proteins are actually protein complexes containing chlorophyll. When the researchers isolate the complexes, they get the associated chlorophylls.—A. Goho

Let there be light

The article on nanotubes as light sources was frustratingly sketchy (“Tiny Tubes Brighten Bulbs: Nanotubes beat tungsten in lightbulb test—maybe,” SN: 6/5/04, p. 356: Tiny Tubes Brighten Bulbs: Nanotubes beat tungsten in lightbulb test—maybe). Any photometric laboratory with a wattmeter could compare the nanotube unit to another light source in a few minutes. It is tempting to think that the heating effect, which must be close to that from a blackbody radiator, and the “electronic effect,” which is undoubtedly a selective radiator, could give a lumen-per-watt efficacy higher than that in incandescence. I hope you keep us posted on this development with some specific data.

Bill Jones
Orange, Calif.

Lively topic

Since the hypoxia described in “Dead Waters” (SN: 6/5/04, p. 360: Dead Waters) isn’t caused directly by the fertilizer, but by the subsequent algae blooms, then perhaps an effective solution is to combat the algae. It might even be profitable to harvest the algae. If the fishing industry is capable of depleting the seas of species that we want there, then it should be equally capable of depleting the seas of species that we don’t want there.

David Charlap
Vienna, Va.

All attention to the so-called dead zone off the coast of our state is certainly welcomed. While the cited authorities clearly stated that data on this phenomenon remain meager, I was surprised that the article made no mention of the continuing debate over interpretations for those data, especially in terms of alternative contributors to hypoxia in the Gulf of Mexico and the relative importance of each.

Darryl L. Felder
Lafayette, La.