Desert Potholes

  • Welcome to Desert Potholes!
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  • Instructions: Click “Play Animation” to see desert potholes before and after rain.

    No Rain
    Play Animation

  • There are naturally occurring holes or indentations in the desert sandstone.

    A pothole is a hole that fills with rainwater, snow melt and wind-blown sediment.

  • Habitats are created for uniquely adapted microscopic organisms in these miraculous ephemeral pools.

  • A pothole’s size determines its diversity and what species live there.

  • Organisms with shorter life spans can live in shallower pools.

  • Those with longer life spans: fairy shrimp, tadpole shrimp, water striders, and whirligig beetles, thrive in the deepest, largest pools.

  • Instructions: Click on each of these amazing creatures that actually live in the desert potholes.

    • Image of a Mite Mite
      Image of a Mite
      Mite

      These creatures are arthropods related to spiders. Mites can be found crawling in miniature pothole ecosystems on the Colorado Plateau that may hold water for only a few hours to a couple days.

      They survive by practicing the “Tupperware” strategy of drought resistance - sealing themselves up under a cuticle layer. They eat a wide variety of material including living and dead plant and fungal material, lichens and carrion.

    • Image of a Predaceous Diving Beetle Predaceous Diving Beetle
      Image of a Predaceous Diving Beetle
      Predaceous Diving Beetle

      The larvae's bodies are shaped like crescents, with the tail long and covered with thin hairs. The larva crawl from the water on the sturdy legs, and bury themselves in mud for pupation. After a few days, they emerge from the mud as adults.

      They have short, but sharp mandibles for hunting invertebrates. Immediately upon biting they deliver digestive enzymes.

    • Image of a Tadpole Shrimp Tadpole Shrimp
      Image of a Tadpole Shrimp
      Tadpole Shrimp

      These tadpole-shaped creatures have a pair of compound eyes, and a shield-like covering over their head and thorax. Some populations have no males and consist of hermaphrodites (individuals with both male and female sex organs). Tadpole shrimp feed on debris, but also prey on fairy and clam shrimp and their eggs. They feed on mosquito larvae and other insects in potholes as well.

      Adults can be over 5 cm long and have up to 70 pairs of legs, depending on the species. They look similar to fossil trilobites and modern horseshoe crabs you may have seen.

    • Image of a Fairy Shrimp Fairy Shrimp
      Image of a Fairy Shrimp
      Fairy Shrimp

      You will see these delicate creatures swimming upside down. Their legs move in a wave-like pattern to propel them. The movements also serve to collect food: algae, bacteria, protozoa, rotifers and floating detritus in the water. Fairy shrimp living in desert areas can tolerate temperatures as high as 40°C (104°F) for several hours. Eggs can hatch shortly after being in water after being buried in desert sand for many years in conditions of dryness, extreme heat, and freezing winter cold. Also, the eggs can easily be blown away by strong wind with dust and travel to other places, and hatch out like seeds of plants when the water covers the ground!

      The adult fairy shrimp have stalked compound eyes, two sets of antennae, and 11 pairs of leaf-like swimming legs.

    • Image of a Tardigrade Tardigrade
      Image of a Tardigrade
      Tardigrade

      These curious critters are also known as waterbears or moss piglets! They have eight legs. Tardigrades can survive in extreme environments. For example, they can withstand temperatures from just above absolute zero to well above the boiling point of water (100 °C), pressures about six times greater than those found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than the lethal dose for a human. They are the first known animal to survive in space.

      In 2007, dehydrated tardigrades were taken into low Earth orbit and exposed to the vacuum and solar radiation of space. They can go without food or water for more than 10 years, drying out to the point where they are 3% or less water, only to come back to life and reproduce! They have been around for more than 500 million years.

    • Image of a Rotifer Rotifer
      Image of a Rotifer
      Rotifer

      Rotifers are freshwater zooplankton, small microscopic animals, that form an important part of the food chain. Rotifers eat dead bacteria, algae, and protozoans. Some species can undergo anhydrobiosis. This means that when a pothole dries up, they can contract into a dormant form and lose almost all body water. When rain falls again and a pool forms, they function well within a few hours.

      Rotifers have bilateral symmetry and a variety of different shapes. The body of a rotifer is divided into a head, trunk, and foot, and is typically somewhat cylindrical. One feature that makes rotifers stand out is a ciliated structure, called the corona, on the head.

    • Image of a Tadpoles Tadpoles
      Image of a Tadpoles
      Tadpoles

      The spadefoot and red spotted toad come out with enough rainfall. They lay eggs in these pools and tadpoles develop rapidly. The spadefoot tadpoles sometimes complete metamorphosis within just 14 days! This is one of the fastest rates of metamorphosis known for any amphibian.

      Interestingly, the tadpoles at hatching are ‘omnivore-morph’ tadpoles, eating both plants and animals. A few change into predatory ‘carnivore-morph’ tadpoles that eat crustaceans and other tadpoles. They are not locked into this state, and can change back to an omnivore!

    • Image of a Back Swimmer Back Swimmer
      Image of a Back Swimmer
      Back Swimmer

      These insects swim on their backs and have one pair of legs specialized as oars! Backswimmers have a stinging beak that is used to catch prey; in potholes they feed on other insects, fairy shrimp, and young tadpole shrimp. The beak runs along 3/4 of the length of the body.

    • Image of a Ostracod Ostracod
      Image of a Ostracod
      Ostracod

      Ostracods are a type of Crustacean as well, sometimes known as seed shrimp. They have been around for about 485 million years! They are small, typically around 1 mm. Their bodies are flattened from side to side and protected by a shell-like covering.

      Most ostracods have no heart or circulatory system, and blood simply circulates between the valves of the shell.

    • Image of a Chironomid Chironomid
      Image of a Chironomid
      Chironomid

      This is the larva of a non-biting midge, a member of the Diptera order (Flies). They have been buzzing around for over 200 million years. Overall, midges are an important food source for fish and predatory aquatic insects. Larvae “clean” the aquatic environment by consuming and recycling organic debris.

      The reddish color is from haemoglobin that is in the midge’s blood. The haemoglobin allows the larvae to breathe under low dissolved oxygen conditions in the pools. You will see them wiggling and writhing, sometimes in masses.

    • Image of a Snail Snail
      Image of a Snail
      Snail

      These creatures are gastropods, of the Mollusk class. They have a single shell and a body that can retract inside.

      Gastropods have been around for more than 400 million years. Most feed on algae, but many are detritivores and some are filter feeders. They practice the "Tupperware" strategy as drought resistors.

    • Image of a Clam Shrimp Clam Shrimp
      Image of a Clam Shrimp
      Clam Shrimp

      Clam shrimp have been on earth since the Devonian time, roughly 420 million years ago! They swim with their legs down or forward. They have a pair of close-set compound eyes, and their body is covered by a carapace which looks like a clam shell.

      Adults are from 2-16mm long and they may have as many as 32 pairs of legs, depending on the species. They feed on detritus or zooplankton.

  • To survive in a pothole, organisms must adapt to extreme environmental changes such as heat and UV light rays.

    The most extreme conditions exist when a pothole dries up completely.

  • Pothole organisms have three main ways to survive living with no water.

    Drought escapers are winged insects, amphibians and invertebrates that breed in potholes but cannot tolerate dehydration (e.g. mosquitoes, adult tadpole and fairy shrimp, spadefoot toads).

    They move or escape, to a new water source when their pothole evaporates.

  • Pothole organisms have three main ways to survive living with no water.

    Drought resistors take another strategy, sealing themselves up with a small amount of water until it rains again.

    Some species of water snail use this approach, as well as pothole mites.

  • Pothole organisms have three main ways to survive living with no water.

    Drought tolerators are able to tolerate a loss of up to 92 percent of the water in their body. Many tolerators have only one stage in their life cycle (e.g., from egg to larva) that can survive extreme dryness.

    The fairy shrimp strategy is to lay eggs that survive in little to no water. Shrimp substitute sugars for water in the eggs they produce, which acts like a kind of antifreeze. The eggs can survive for decades and be revitalized by a rainstorm. Bacteria and algae living in potholes also use this strategy.

  • Instructions: Find and select all 4 Fairy Shrimp, and 2 Clam Shrimp in the desert pothole below.

    Selection Choice One Selection Choice Two Selection Choice Three Selection Choice Four Selection Choice Five Selection Choice Six Selection Choice Seven Selection Choice Eight
    This is a Snail.
    Try Again!
    This is a Back Swimmer.
    Try Again!
    Good Job!
    Fairy Shrimp

    0 of 4

    Clam Shrimp

    0 of 2

  • A pothole is a unique habitat that is very easily disturbed

    Pothole organisms are sensitive to sudden water chemistry changes, temperature changes, sediment input, being stepped on, and being splashed onto dry land.

    Human use of pothole water by swimming, bathing or drinking may change the salt content or pH of a pool drastically.

    More importantly, this change occurs suddenly, unlike the slow, natural changes to which organisms are able to adapt over time.

  • Congratulations! You are now a junior pothole scientist!

    While these potholes and the life that lives in them may seem unimportant, they can act as an indicator of the health of the larger ecosystems in which they occur.

    Please help educate others on the fragile nature of potholes and how we can protect them by not touching or swimming in them.

    Therefore, we can witness the miraculous ephemeral life cycles that unfold before us for generations to come.