Many people have never heard of salps until they come across them when they are in one of many oceans around the world. A salp is an unusual looking creature that is a free floating tunicate and is barrel shaped. The creature is able to move by pumping water through its body, which is jelly like. When the salp pumps the water through its body it strains it and feeds on the phytoplankton that is in the water. These tunicates are quite interesting to look at because of the simple yet complex way that they move through the water and feed at the same time.
A string of salp captured in the Red Sea
Salps are found in most seas but are found in the largest amount in the Southern Ocean. You may see just a few at a time in other areas, but in the Southern Ocean they are usually seen in deep waters and are in large groups or swarms. The animals float on their faces on their own or they are often in colonies that float together in a string or rope like manner. It’s quite impressive when you see a whole colony of salp, moving along together in perfect rhythm.
Salps dine on phytoplankton and they move around the seas according to phytoplankton blooms. When there are many phytoplankton the salps move into the area and consume them all. The species is so adept and successful when there is plenty of food that they can actually clone themselves and the clones graze upon the phytoplankton and grow faster than any other multi-cellular animals.
What is interesting is that because the salps have to pull the water through their bodies to both eat and move, when they are in very dense populations of phytoplankton they can actually become clogged with their food source and sink! When this happens it is not uncommon for the beaches to be full of slippery salp bodies that have become clogged and then wash up onto the beaches. In areas with dense phytoplankton populations it is common to see the salp bodies on the beaches, especially during phytoplankton blooms. Because the salp feed off the phytoplankton but can become clogged with them, causing their demise, the two species are always in competition with both of their numbers fluctuating in any given area or period of time.
Impact on the Ocean
At first glance the salp seems very unimportant or inconsequential to ocean life, but this is not the case. The fact is, both sinking fecal pellets from the species as well as salp bodies bring carbon to the sea floor. It wouldn’t be a big deal if there were just a few salp, but there are enough of both the fecal matter as well as the bodies on the ocean floor that the species has a huge impact on the biological pump of the ocean. Because of this impact, the density of salp in an area is known to change the ocean’s carbon cycle, and even contribute to climate changes in the area!