Based on the above principles, Bian Xiao will talk about today's topic. Why are the fish living in coral reefs colorful? Because coral is colorful, fish is colorful, which is just in harmony with its living environment, thus preventing its natural enemies from attacking it. The fish living in rivers have a single environment. Seen from the water, the sky is white; Looking down from the air, the water is mostly turbid or dark brown (gray), and the color of fish (gray or grayish brown) is just right for the environment. So the color of the fish is just its self-protection measures.
Coral reef is a complex biological group composed of many microorganisms interacting for mutual benefit (usually for survival), and the relationship between them is called symbiosis. The relationship between clownfish and anemones is well known to us. Coral reef managers know that most corals can't survive without zooxanthellae, and vice versa. The relationship between small tropical fish and small tentacle coral is conclusive. Many small tropical fish use coral branches as their shelters and nests. In exchange, corals have a "guard" and a "housekeeper", and they can get nutrition from the excrement of these fish.
But a new study in the Journal of Experimental Biology found that this symbiotic relationship is much deeper than our previous superficial understanding. Want to increase the rate of photosynthesis? Let fish live in coral reefs. This is the first time. The researchers found an impressive phenomenon: small tropical fish and gray-edged mud fish appeared in the calyx-shaped columnar coral of the small tentacle coral, which enhanced the photosynthesis of the coral.
. This is because the movement of small tropical fish makes water flow around coral branches, which enhances the photosynthesis of coral. When a small tropical fish swims among the branches of a coral column, its ventilation can increase photosynthesis by 22%. This new discovery was put forward by Dr Tim and Nader Riddle in a recent article, and showed us how water movement can help corals improve photosynthesis.
Of course, a small tropical fish will not live in coral all the time. The researchers spent a whole day calculating that the role of small tropical fish accounts for 3%-6% of coral photosynthesis, which is still of great benefit to corals. Small tropical fish also seem to benefit from this photosynthesis. When the researchers put this small tropical fish in dead coral instead of living coral, they measured that its breathing frequency was higher. Experts say that the accelerated breathing rate is the result of increased pressure. Both living corals and dead corals provide shelter for small tropical fish. However, some substances in living corals give more peace to small tropical fish, thus reducing their breathing frequency. Among living corals, it is really easier for fish to breathe. This study shows that coral reefs and fish are intricately intertwined in ways that we don't fully understand.