East Coasters heading to the shore this weekend may notice piles of gelatinous blobs scattered across the beach, washed up by changes in ocean currents. Despite the fact that they're sometimes called jellyfish eggs, these harmless bits of goo are actually their own distinct species: Sea salps.
There are over 50 different sub-species of sea salps, but the ones you'll see on American beaches are about thumbnail-size—on the smaller end of a spectrum that includes species that grow to almost a foot. They're members of the tunicate family, and, unlike jellyfish, contain primitive backbones inside their relatively glassy bodies.
Salps reproduce unlike nearly anything else in the animal kingdom. Initially, they reproduce asexually, creating a chain of salp clones that take distinct shapes depending on the subspecies (usually either wheels or double helixes). The clone chains can be vast, growing up to 50 feet in length, but eventually, they break apart into individual females, each with a single egg inside.
The females are then fertilized by males (we'll get to them in a minute), and the eggs they contain become embryos. Here's where things get really crazy: With the embryo still growing inside, these mothers-to-be grow testes, becoming the males that will fertilize new individual salps once they're released from the chain. When the new generation is born, it will be their turn to produce clone chains of their own, beginning the process anew.
As incredible as their unusual mating practices are, the salps' ability to subtly combat climate change makes them especially fascinating. Algae depends on carbon dioxide in order to flourish. During the chain-making process, salps ingest copious amounts of said algae. Salps then excrete heavy fecal pellets, full of carbon dioxide, that sink rapidly through the water. In other words: The salps' digestive process removes CO2 from the carbon cycle and deposits it on the bottom of the ocean floor.
Larry Madin, executive vice president and director of research at the Woods Hole Oceanographic Institution in Massachusetts, says that while this won't be able to reverse the tide of climate change, "It's one way of trying to balance out how much CO2 is in the atmosphere."
[h/t National Geographic]