Barrel ciliate
Coleps hirtus
The barrel ciliate is a widespread single-celled ciliate characterized by its distinct barrel-like shape. Its body is protected by an armor of calcified alveolar plates arranged in regular longitudinal and transverse rows. It moves swiftly and often rotates through the water, swimming with the help of its cilia. The species is known for its role as a scavenger and predator within the microcosm of freshwater ecosystems.
Details
Identification
Barrel-shaped body, armor plates made of calcium carbonate, terminal oral opening with a basket-like apparatus, spine-like projections at the posterior end.
Social behavior
Solitary, but can reach very high population densities when food supplies (e.g., bacterial blooms) are abundant.
Diet
Omnivore and scavenger; feeds on bacteria, flagellates, algae, and tissue remains of dead micro-organisms.
Hunting strategy
Active searching for food sources via chemotaxis; uses oral cilia to create currents that draw in particles.
Overwintering
Formation of dormant stages (cysts) under unfavorable environmental conditions such as cold or desiccation.
Ecology
Ecological role
Important component of the microbial loop; decomposes organic matter and serves as prey for larger zooplankton.
Natural predators
Larger predatory ciliates, rotifers, and small planktonic crustaceans.
Competitor species
Other bacterivorous and detritivorous ciliates such as Paramecium or Urotricha.
Ecosystem service
Contributes to the self-purification of water bodies and nutrient recycling within the aquatic ecosystem.
Threats
Extreme chemical pollution or complete desiccation of habitats without cyst formation.
Scientific profile
Profile
Habitat
Widely distributed in freshwater (lakes, ponds, running waters); inhabits the pelagic zone (plankton) as well as the benthic zone (sediment surfaces) and periphyton.
Reproduction
Asexual reproduction by transverse binary fission; sexual reproduction via conjugation for genetic exchange.
Ecological role
Key component of the microbial loop; controls bacterial and algal populations and serves as a link to higher trophic levels (zooplankton).