Living on Algae’s Efforts

In most of the dunes, plants need special adaptations to deal with the gypsum, or calcium carbonate, in the soil. Plants that have evolved special techniques for dealing with such calcium carbonates are called gypsophiles, and the Chihuahuan Desert has more such plants than any other desert.

Fortunately, a variety of algae has also developed mechanisms to handle the minerals in the dune sands. Just beneath the blinding white surface, it forms a green layer that constitutes the true base of the food chain in the strange world of the dune’s ecosystem. The algae provide the only organic matter in most of the dune field. They also chemically alter the scarce nitrogen they find in a way that makes it useable for other plants and animals. These algae, together with certain bacteria, provide the nutrients the plants growing on the dunes need to survive. Ironically, these desert-dwelling algae are directly related to the blue-green algae that live at certain depths in the ocean. Having adapted to desert sand dunes, the dry, encysted, seedlike cells of the algae can survive for up to 0 years in dry desert soils to resume growth as soon as they get enough water.