• Despite resembling plants, being stationary and colorful, sponges (phylum: Porifera) are actually animals—the most ancient lineage of all animals. Largely hollow, sponges filter feed by using tiny flagella to pump water throughout their structure, from which they gather nutrients and oxygen. Some sponges form mutualisms with plants and animals, where the sponges can provide habitats for other species to thrive.

    As marine species, sponges are sensitive to many climate change-related challenges, such as rising temperatures and ocean acidification. They are also susceptible to pollution, such as agricultural runoff. Even turbid water from human activity on the ocean floor can interfere with their ability to filter feed. Though found worldwide, decreasing numbers of sponges will put a strain on the many animals that use them for habitat, protection, and food.

    1. How do sponges feed and breathe?

      They filter feed, by pumping water through their hollow bodies using flagella to gather nutrients and oxygen.

    2. What sorts of challenges do sponges face?

      Sponges are at risk from pollution, human activity on the ocean floor, rising ocean temperatures, and ocean acidification.

    3. Why are decreasing numbers of sponges cause for concern?

      Sponges provide food, habitat, and protection for other plants and animals.

  • Term Part of Speech Definition Encyclopedic Entry
    climate change Noun

    gradual changes in all the interconnected weather elements on our planet.

    Encyclopedic Entry: Earth's Changing Climate
    filter feeder Noun

    aquatic animal that strains nutrients from water.

    mutualism Noun

    relationship between organisms of different species, in which both organisms benefit from the association.

    ocean acidification Noun

    decrease in the ocean's pH levels, caused primarily by increased carbon dioxide. Ocean acidification threatens corals and shellfish.

    runoff Noun

    overflow of fluid from a farm or industrial factory.

    Encyclopedic Entry: runoff
    turbidity Noun

    cloudiness or lack of transparency.