Bayou-Diversity (23 September 2018) Okay, here’s the Louisiana bayou trivia question of the day. Just what are those softball-sized, jelly-like globs that are often seen attached to bayou trees and boat docks, especially after water levels fall? Impress your friends with this answer: Bryozoan Colony. These gray, gelatinous masses are actually colonies of thousands of individual animals called zooids. Each zooid is a microscopic creature complete with a mouth, digestive tract, muscles, and nerves. The jelly-like material serves as a protective matrix for the colony. Individuals feed by filtering tiny algae from the water through tentacles. Since algae don’t usually grow well in muddy water, the presence of bryozoan colonies in a stream can be an indicator of good water quality, at least in terms of turbidity. Colonies grow in size by budding from the adult zooids. New colonies are established from free-swimming larvae produced by the zooids. There are many species of bryozoans, but most live in salt-water environments. Of the approximately 20 freshwater species found in North America, most live in warmer regions.
Studies have shown that humans are much more susceptible to develop an affinity for animals that have soft, furry coats and large eyes than for creatures without backbones. So where does that leave the blind, slimy, bayou dwelling invertebrates that make up the bryozoan colony in terms of popularity? Well, as long as we don’t pollute all of our waterways, it probably doesn’t matter. Bryozoans have been around for 450 million years according to the fossil record and will probably be here long after we’ve stopped asking trivia questions. (adapted from Bayou-Diversity: Nature & People in the Louisiana Bayou Country, LSU Press)