Nature Nugget – Branchiopod Time Capsule

fairy shrimpFound around the world, except in Antarctica, Branchiopods are a group of crustaceans that live in temporary pools and saline lakes. Branchiopod means “gill foot,” because they obtain oxygen from the water through their feet. There are numerous varieties of Branchiopods. Most are microscopic in size. Only three orders of them are considered large enough to see easily with the naked eye. These large Branchiopod orders are the fairy shrimps, clam shrimps, and tadpole shrimps.

The fairy shrimps, which also include the brine shrimps, unlike other large Branchiopods, have stalked compound eyes and lack having a shield covering the body. Reaching a size of .5 to 1.5 inches, fairy shrimps swim on their backs with their legs up toward the light. They feed on algae, bacteria, microorganisms, and detritus, which they filter from the water with their legs while swimming. Adult females carry their mature eggs, before laying them, in an ovisac where they can be supplied with oxygen.

The clam shrimps are less than half an inch long and have internal compound eyes and a large bivalve shield, resembling a clam’s shell, which covers the entire body. They spend most of their time on the bottom of rain pools filter feeding, sometimes dug into the mud like mussels. They can also swim with the use of their legs and second antennae. Clam shrimps develop very quickly, reaching maturity within a few days of hatching. Thus they are excellently adapted to the extreme conditions of temporary bodies of water.

Tadpole shrimps resemble miniature horseshoe crabs, having a flattened shield that covers most of the body and the internal compound eyes. They are also called Triops, because they have three eyes. Varying from 1 to 3 inches at maturity, Triops are hermaphrodites, meaning that they are self-fertile and do not require another Triop for reproduction. Triops inhabit temporary, freshwater pools, often in deserts, where they live on the bottom of the pools and dig in the mud looking for plankton, worms, insect larvae, and tadpoles on which they feed. Since these pools are short-lived, the Triops consequently have short life spans with a maximum of up to 90 days. They are capable of completing their life cycles in 20 to 40 days.

The most amazing thing about Branchiopods is how their eggs are perfectly adapted to the temporary bodies of water in which they live. Some eggs hatch right away after being laid, but some require the pool going completely dry, then reflooding again, before they will hatch. Called “resting eggs,” these eggs contain embryos that are in diapause (suspended animation) and are capable of surviving in completely dried up pools. When the female senses the pool is drying up, she sends a chemical message to the eggs before she lays them. This message stops the development of the eggs when they are either 13 or 27 days old. This same message lets the eggs know that when they are exposed to water again it will be time to hatch. Thus the embryo manages to survive without any metabolism, remaining viable for decades. The eggs are often carried by wind to other pools and are resistant to extremes in temperature.

It is so amazing how God has given His creation the ability to survive, even under extreme circumstances, as we have seen with the Branchiopods! “Our Father in heaven is the source of life, of wisdom, and of joy. Look at the wonderful and beautiful things of nature. Think of their marvelous adaptation to the needs and happiness, not only of man, but of all living creatures. . . . It is God who supplies the daily needs of all His creatures.” Steps to Christ, 9.

David Arbour writes from his home in DeQueen, Arkansas. He may be contacted by e-mail at: landmarks@stepstolife.org.