We are trying not to squish them as we walk on the shore. Trying not to touch them because we think they may sting, or bite. Perhaps a brave few are swimming amongst them. But what on earth are they? Those little gelatinous blobs currently floating en masse in the ocean and washing up in droves on the shore. A good first guess would be jellyfish. A second guess could be eggs of some kind. Alas, they are neither—these itty-bitty diaphanous orbs are salps, a wondrous sea creature worth knowing more about.
Also called “sea grapes” or “jellybeans of the sea,” salps are easily mistaken for small jellyfish. However, the salp is a member of Tunicata, or “sea squirts” and are taxonomically more closely related to humans than jellyfish. They move about the ocean by means of jet-propulsion, taking in water, filtering it for food, and then pushing it out to scoot about their underwater world. They eat whatever they manage to catch in the process, including microscopic bacteria, phytoplankton and larvae. Salps can be found zooming about in every ocean save the Arctic.
Not unlike honeybees, salps function together as one unified organism — at least some of them. It begins with a complicated life cycle. A solitary salp, called an “oozooid,” reproduces asexually by cloning to form one part of what will become a salp chain. The other members of the chain are clonal members called “blastozooids” and are sequential hermaphrodites. They are at first females who reproduce sexually after being fertilized by a male (the next level of maturity) from another, older, chain. This yields new solitary oozoids. And so on and so forth. Once enough, salps have been cloned, they form a chain community, which can grow up to 45 feet long. The individual salps each have specific functions such as movement, feeding, and reproduction. They are even capable of moving as a group, in synchronicity, like a flock of birds. Yet some salps choose to go it alone and remain solitary.
Salps are believed to be one of the fastest growing multicellular animals, able to increase their body length at a rate of 10 percent per hour. They are also capable of bioluminescence and are one of the brightest bioluminescent sea creatures out there. And as if this were not enough to celebrate the friendly salp, they are also magnificent environmentalists.
Salp poop sequesters carbon. Because the salp’s diet consists largely of phytoplankton, which consume carbon dioxide in the process of photosynthesis, salps produce dense, carbon-packed, fecal pellets that readily sink to the ocean floor. With less carbon at the surface, the ocean is better able to absorb carbon dioxide from the atmosphere.
So hail the happy salp. If you see them on the shore, worry not, they are no longer living. If you encounter them in the open ocean, swim on in, swimming amongst the salps has been described as “a pleasant experience, somewhat akin to swimming with marshmallows, or in tapioca pudding.” Why not?
(A special thank you to Nancy Coffey who visited The Cricket office to tell us about the arrival of the salps on local beaches and encouraged us to write about them.)
