Salp
Barrel-shaped planktonic tunicates with efficient jet propulsion.
Salps (singular: salp; also known as salpa, plural salpae or salpas) are barrel-shaped, planktonic tunicates in the family Salpidae. They move by contracting their gelatinous bodies to pump water through them, making them one of the most efficient examples of jet propulsion in the animal kingdom. Salps feed on phytoplankton by straining water through internal feeding filters. They are common in equatorial, temperate, and cold seas, often seen at the surface singly or in long, stringy colonies, with the most abundant concentrations in the Southern Ocean near Antarctica, where they sometimes form enormous swarms.
- field
- Marine biology (planktonic tunicates)
- known_for
- Efficient jet propulsion; rapid response to phytoplankton blooms; alternation of generations life cycle; role in ocean carbon cycle
- distribution
- Equatorial, temperate, and cold seas; especially abundant in the Southern Ocean
Lore & Background
Salps have a complex life cycle with an obligatory alternation of generations. The solitary phase, or oozooid, is a single barrel-shaped animal that reproduces asexually by producing a chain of tens to hundreds of individuals. The chain forms the aggregate portion, with individuals called blastozooids that remain attached while swimming and feeding. Each blastozooid reproduces sexually as a sequential hermaphrodite, first maturing as a female and fertilized by male gametes from older chains. The growing embryo oozooid is attached to the parent's body wall and eventually released to become the solitary asexual phase, closing the cycle.
Reader's Guide
Salps are significant because of their rapid reproduction and ability to form blooms that can strip phytoplankton from the sea, affecting other planktonic species. Their sinking fecal pellets and bodies carry carbon to the seafloor, making them important to the ocean's biological pump. Large changes in their abundance or distribution may alter the ocean's carbon cycle and potentially play a role in climate change. Salps are chordates, related to vertebrates, and small fish sometimes swim inside them for protection.
Did You Know?
- Salps are one of the most efficient examples of jet propulsion in the animal kingdom.
- The most abundant concentrations of salps are in the Southern Ocean, where they sometimes form enormous swarms.
- Small fish swim inside salps as protection from predators.
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