Substrate
Different life stages of comatulid crinoids such as C. glebosus have different interactions with the substrate. During the temporary stalked stage of a comatulid (pentacrinus stage) there is a direct dependence on the substrate due to the stalk needing to be cemented to a suitable hard substrate by a calcium carbonate secretion (Alender et al 1966). A variety of objects have been found to be utilized as a hard substrate such as the dorsal cirri of an adult individual, or pogonophoran tubes (Alender et al 1966).
Adult comatulids (free living crinoids), still have a direct dependence on the substrate due to the fact that they are essentially sedentary animals that spend most of their life in one position in the environment, even though they have mobility and swimming capabilities (Alender et al 1966). Although the pentacrinus crinoid stage requires a hard substrate to cement to, this is does not apply to the free-moving stages of comatulids (Alender et al 1966). As described in external anatomy, the shape and length of the cirri determines what type of substrate the species is found in. Most comantulids, like C. glebosus, have cirri with short joints and claw-shaped distal cirrus joints that enables them to hold onto projecting objects like rocks and coral, while those found in soft sediment habitats have elongated cirrus joints and a larger number of cirri to avoid sinking into the sediment (Alender et al 1966).
Species in reef habitats find sheltered positions under overhanging rocks or coral and can position their mouth in various directions with the tube feet and ambulacral, food-groove mechanism still able operate (Alender et al 1966). Rock pool habitats are usually avoided due to the instability and wave action while the outer sides of breakwaters are a suitable habitat for the species that live on the outer slope of coral reefs (Alender et al 1966). Mud bottomed habitats are only suitable if there is little suspension of mud particles and are in sheltered waters(Alender et al 1966).
Water Movement
The high efficiency of the crinoid feeding system, in particular the tube feet and their associated mucous glands,in capturing micronekton and plankton means that crinoids are not necessarily dependent on the strength of water currents (Alender et al 1966). The main role of water currents in regards to crinoid habitats is mainly regarding the oxygenation and relative purity of the water from toxic substances (Alender et al 1966). In shallow habitats, such as where C.glebosus was found, the normal sea movements will maintain that environment in a state of relative stable purity (Alender et al 1966). However too much water movement and wave action is not tolerated by crinoids due to the delicacy of their body parts and the possibility of fouling within the small pores of the water vascular system due to sediment disturbance (Alender et al 1966).
Salinity
Crinoids are similar to other echinoderms in the sense that they are unable to tolerate large variation in salinity and are unable to survive in brackish and freshwater environments(Alender et al 1966). Crinoids are able to tolerate temporary changes in salinities, in regards to storm and drought effects on shallow water environments, but as seen by their preference for the outer side of reefs, they have a limited tolerance for salinity changes (Alender et al 1966). It should be noted that although they don’t tolerate changes in salinity, changes in salinity aren't lethal to crinoids and would cause them to migrate out of the affected area (Alender et al 1966).
Light
Crinoids cannot tolerate strong illuminations such as direct sunlight, and react strongly by withdrawing into shadier locations (Alender et al 1966). It is suggested that photoreceptors may lie within the dermis and act in association with the superficial nervous system but further studies are needed to confirm their presence (Alender et al 1966).
Depth and Pressure
Crinoids, mostly comatulids, are shallow water forms and can only tolerate limited changes in depth (stenobathic). Whereas ancestral and stalked crinoids have been found in deeper ecosystems (Alender et al 1966).