Aquatic antagonists: bluegill (Lepomis macrochirus)

A fixed action pattern (FAP) is a specific, hard-wired sequence of behaviors that occurs in response to an external stimulus, called a sign stimulus. The behavior is “fixed” because it is essentially unchangeable—proceeding similarly across individuals of a species every time it occurs.

Microbial predation refers to the process by which one microorganism kills and consumes another to obtain nutrients and energy. It encompasses both bacterial and protozoan predators. This interaction plays a crucial role in shaping microbial communities and regulating nutrient cycling.Bacterial Predators: Epibiotic vs. EndobioticBacterial predators are classified based on their mode of attack as either epibiotic or endobiotic. Epibiotic predators, such as Vampirococcus, attach to the surface of...

Freshwater systems such as streams, rivers, and lakes exhibit distinct physical and biological characteristics that influence their microbial communities. These environments are broadly categorized into lotic systems—those with flowing waters like streams and most rivers—and lentic systems, which include still or slow-moving waters such as lakes, ponds, and marshes.In lentic systems, phytoplankton drive primary production, generating autochthonous organic carbon. In contrast, lotic systems...