Freshwater ponds provide a home for a wide variety of aquatic and semi-aquatic plants, insects, and animals. The vast majority of pond inhabitants, however, are invisible until viewed under the microscope. Beneath the placid surface of any pond is a microscopic metropolis bustling with activity as tiny bizarre organisms pursue their lives; locomoting, eating, trying not to be eaten, excreting, and reproducing. In this collection of digital movies, observe the activities of microscopic organisms taken from a typical North Florida pond.
Aeolosoma (Annelida) Videos
These transparent microannelids inhabit soils and decaying material in stagnant water, using cilia to move about.
Chaetogaster (Annelida) Videos
Chaetogaster is a genus of freshwater worms that belongs to the annelid family, Naididae. Chaetogaster species are predators, actively hunting and consuming smaller organisms.
Hydra (Coelenterata) Videos
Unlike the marine coelenterates, hydras live in freshwater habitats. They have four types of nematocysts, or cnidae, the microscopic stinging capsules found in coelenterates.
Daphnia (Crustacea) Videos
Daphnia, or water fleas, are microscopic crustaceans that populate the quiet waters of lakes and ponds throughout the world.
This cladoceran is one of many varieties of water flea and can be found along weedy margins of ponds and ditches.
Nauplius (Crustacea) Videos
The nauplius is a larval form common to many species of crustaceans. It is the first larval stage that emerges from the egg and the earliest free-swimming phase in crustacean development.
Ceratopogonids (Diptera) Videos
Biting midges, also called sand flies, no-see-ums, and punkies, are the smallest of the biting flies. They are well known for their painful bites to humans and animals, but some species bite only other insects.
Chaetonotus (Gastrotricha) Videos
Chaetonotus is the largest freshwater gastrotrich and can be found in plant-choked ditches and mossy ponds.
Nematode Worm (Nematoda) Videos
Nematodes range in size from microscopic to seven meters (about 23 feet) long, the largest being the parasitic forms found in whales. They have elongated bodies, usually tapered at both ends, and have a bilateral symmetry.
Dalyellia (Platyhelminthes) Videos
Dalyellia belongs to the order Rhabdocoela, a highly diverse group of flatworms. There are many free-living representatives as well as some species that live symbiotically within the bodies of larger organisms.
Microstomum (Platyhelminthes) Videos
These are small, elongated turbellarians, with an anterior mouth, and simple gut. They can be found under rocks, submerged leaves, and other debris, where they feed on tiny crustaceans, microorganisms, and organic particles.
Stenostomum (Platyhelminthes) Videos
This genus belongs to the order Catenulida, a mainly freshwater group of flatworms, with some marine representatives. This group is different from other turbellarians, with a ciliated, sac-like intestine, simple pharynx, and unpaired gonads.
Actinophrys (Protozoan) Videos
These heliozoans are found most often in freshwater, floating in the open water amongst reeds and filamentous algae. Heliozoans are spherical and are frequently enveloped by a shell made of silica or organic material.
Amoeba (Protozoan) Videos
Amoebas are primitive organisms characterized by their flowing movements, extending cytoplasm outward to form pseudopodia (false feet); this type of movement is considered to be the most primitive form of animal locomotion.
Bursaria (Protozoan) Videos
Bursaria is one of the ciliates, considered the most complex of the protozoan groups. These organisms are large enough to be barely visible, and are characterized by a distinctive "big mouth," or cytostome, which they use to scoop up protozoan prey.
Coleps (Protozoan) Videos
This barrel-shaped ciliate is covered by a layer of protective, calcareous plates and is commonly found in freshwater. Coleps is a rapid swimmer, revolving as it travels and using this motion to bore out chunks of other protozoans it is feeding upon.
Euglena rostrifera (Protozoan) Videos
This species is a member of the protozoan order Euglenida, a remarkable group of single-celled creatures, many of which exhibit characteristics of both plants and animals.
Euplotes (Protozoan) Videos
Euplotes belongs to the ciliate order Hypotrichida whose species are characterized by rows of fused cilia called cirri on the ventral surface. A freshwater inhabitant, Euplotes uses its cirri for swimming and also to “walk” along a substrate.
Loxophyllum (Protozoan) Videos
A ciliate that lives in freshwater habitats, Loxophyllum preys upon rotifers and other ciliates. It has groups of trichocysts in wart-like protuberances that it uses for immobilizing prey.
Metopus (Protozoan) Videos
Unlike most other ciliates, which are aerobic, Metopus is anaerobic and lives in oxygen-depleted sediments. Some species have even been found living in sediments off the coast of Antarctica.
Paramecium (Protozoan) Videos
A well-known visitor to the classroom microscope, this slipper-shaped ciliate is commonly found in freshwater ponds. They feed on other microscopic organisms, sweeping them into a funnel-shaped gullet.
Peranema (Protozoan) Videos
A colorless euglenoid, Peranema has two flagella, although only one is usually visible through the microscope. These flagellates live in both freshwater and marine, environments as well as soil and as parasites.
Spirostomum (Protozoan) Videos
Some of the largest ciliates belong to the genus Spirostomum, some species large enough to see with the naked eye. These organisms hold the record for the fastest body contractions of any living cell.
Stentor (Protozoan) Videos
Also known as the "trumpet animalcule," Stentor is one of the largest ciliated protozoans. Cilia lining the “trumpet” beat rhythmically, drawing food into the mouth of the organism.
A relative of the paramecium, Urocentrum is a rotund ciliate slightly bifurcated by a two distinct bands of cilia and sporting a tufted “tail” of fused cilia on its posterior. The organism spins on this tail, swimming rapidly in a slightly irregular spiral.
Volvox (Protozoan) Videos
Volvox is a colonial organism made up of 500 to 60,000 bi-flagellated cells embedded in a gelatinous wall. It has something of a dual identity amongst biologists, placed by zoologists into the order Volvocida and classified by botanists as a green algae, Chlorophyta.
Vorticella (Protozoan) Videos
These bell-shaped ciliates live in fresh or salt water attached by a slender stalk to aquatic plants, surface scum, submerged objects, or aquatic animals.
Brachionus (Rotifera) Videos
These rotifers have a transparent turtle-like shell called a lorica and are found in a variety of habitats, freshwater and marine. Several species are cultured to provide food for fish larvae in aquaculture.
Collotheca rotifers are sessile; they are attached to each other forming a spherical colony, or attached singly to the substrate. Collotheca have extremely long tentacle-like cilia surrounding the corona.
Mytilina (Rotifera) Videos
Species belonging to this genus are loricate and are found mostly in littoral habitats. Since the lorica is glasslike, like members of the genus Euchlanis, it is easy to view their internal organs.
Philodina (Rotifera) Videos
Philodina belongs to the class Bdelloidea (from the Greek for leech), rotifers that have two ovaries. This type of rotifer moves in two modes, free-swimming and inchworm-like movements along surfaces. Males have never been observed.
Squatinella (Rotifera) Videos
Rotifers belonging to this genus are commonly found in littoral (shoreline) habitats among aquatics. In most species, the corona is covered by a semicircular shield, which is used to scrape small organisms into the mouth while browsing over underwater plants.
Echiniscus (Tardigrada) Videos
This genus of water bear is widespread and common. Their bodies are short, plump, and contain four pairs of limbs that are poorly articulated, a characteristic typical of soft-bodied animals. They lumber about in a slow bear-like gait over grains of sand and dirt or pieces of vegetation.