Heliozoa refers to a group of tiny, microscopic organisms, commonly found in freshwater and marine environments, belonging to the kingdom Protista. They are categorized under the phylum Actinopoda and class Granuloreticulosea. Heliozoa are characterized by their distinctive appearance and unique feeding methods.
These organisms possess a spherical to amoeboid shape, with numerous needle-like projections called axopodia radiating from their body. The axopodia are supported by microtubules, and they serve various functions such as movement, feeding, and capturing prey. Consequently, heliozoa are often referred to as "sun animals" due to their appearance resembling a miniature sun surrounded by rays.
As heterotrophic microorganisms, heliozoa display a mixotrophic feeding behavior. They primarily feed on bacteria, algae, and smaller microscopic organisms by extending their axopodia and capturing food particles. Once captured, the prey is engulfed within the heliozoan's body by pseudopodial movement.
Heliozoa play an essential role in aquatic ecosystems, contributing to nutrient cycling and serving as indicators of water quality. Their distribution spans various habitats worldwide, ranging from freshwater lakes and ponds to oceans and salt marshes. They are particularly abundant in regions with optimal environmental conditions, such as warm temperatures and sufficient sunlight.
In summary, heliozoa are minute single-celled organisms characterized by their spherical or amoeboid shape and the presence of radiating axopodia. They exhibit mixotrophic feeding behavior, capturing and engulfing smaller organisms using their specialized projections. These microorganisms play important ecological roles and are widely distributed in aquatic environments.
