Saturday, April 21, 2007

Darwin's Paradox 2

"Darwin's Paradox" isn't just the title of my new book by Dragon Moon Press. It's a term that describes a peculiar enigma in tropical oceans. Ever since Charles Darwin described coral reefs as oases in the desert of the ocean, oceanographers were struck by a peculiar irony. Coral reefs are one of the richest ecosystems on Earth, with productivity ranging from 50 to 250 times more than the surrounding ocean; yet they thrive in crystal-clear water largely devoid of nutrients. This apparent violation of the laws of thermodynamics (high productivity in a low-productivity environment) has long puzzled scientists who coined the phenonemon: Darwin's Paradox. Well, part of the answer is the coral's shape and their efficiency in recycling nutreints like nitrate and phosphate. Any of you who have snorkeled in the tropics and seen corals will know that they have extremely rough surfaces. The rough coral surface amplifies any water turbulence at a microscopic level, disrupting the boundary layer that usually settles on objects under water, and lets the coral "hoover" up the sparse nutrients. Lots of corals also act as "landlords" to specialized algae (called zooxanthelae), which provide the coral with food (by products of photosynthesis) and, in turn, get food from the wastes created by the coral. VERY COOL isn't it? In fact, many coral communities function as both plant and animal in this symbiotic relationship. I guess it's like having your cake and eating it, too.

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