Sea Vase

Overview

The Sea Vase (Ciona intestinalis) is a solitary, sessile tunicate often found in dense, unfused aggregations. As a primitive chordate, it serves as a vital model organism in developmental biology due to its simple body plan and compact genome.

Appearance

This species features a soft, translucent, and cylindrical body that can reach up to 15 cm in length. Its pale greenish-yellow color allows the internal organs to be seen through the body wall. It possesses two siphons: a terminal inhalant siphon with eight lobes and a sub-terminal exhalent siphon with six lobes, both often marked with distinctive yellow margins and orange or red pigment spots. Five longitudinal muscle bands are typically visible along the body.

Distribution & habitat

Widely distributed throughout temperate regions, the Sea Vase is commonly found from the lower shore down to depths of 500 meters. It thrives in sheltered environments with moderate water flow, frequently colonizing man-made structures like piers, pilings, floating docks, and ship hulls, as well as natural substrates such as bedrock, boulders, and seaweed.

Biology & behavior

Adults are sessile, anchoring themselves to surfaces with short, root-like projections called villi. They are filter feeders that draw water through their siphons to extract nutrients. The species is known for its rapid growth and opportunistic nature, often exhibiting "boom and bust" population cycles. While the adult is stationary, the organism begins life as a free-swimming, tadpole-like larva that possesses a notochord and dorsal nervous system, highlighting its evolutionary link to vertebrates.