“What’s that on the beach?!" Monterey Bay...

“What’s that on the beach?!" Monterey Bay…

“What’s that on the beach?!” 

Monterey Bay beachcombers and divers were treated to a huge bloom of salps this weekend! Salps are gelatinous filter-feeders that drift with and feed in the plankton. Wind and waves sometimes blow these open-ocean emissaries onshore by the thousands, a feast for fishes, invertebrates—and for the eyes of curious naturalists!

There were several species of salps in this weekend’s bloom, including these in the genus Salpa. Salps do not sting—in fact, they’re more closely related to fishes and people than they are to other “jellies”! The brown/orange orb is the salp’s gut. Pumping muscle bands push water from one end of the animal to the other through an internal plankton-pasta strainer.

Salps have an incredibly successful reproductive strategy, allowing them to explode in numbers when conditions are right. Ready? Here we go: Salps can be found as solos, or as a chain of dozens of individuals attached together. Same species, two different body morphs. The solos produce the chain asexually, and the individuals in the chain are all clones. 

OK, still with us? The next part is a doozy: A young chain is female, and each female clone produces another solo salp from an egg that is fertilized by older male chains. The older male chains are female chains that changed sex as they aged—this is called sequential hermaphroditism. This whole process allows salps to produce new generations at an incredible rate, to take advantage of fleeting oceanic conditions. Phew, we did it!

Salps are thought to have an outsized effect on the flow of nutrients in the ocean’s food web. Because their fecal pellets sink, salp poop delivers vital nutrition from the ocean surface to the deep seafloor, and helps take carbon from the atmosphere to the deep, which helps regulate the planet’s climate. Spent salps from these huge blooms become food for countless organisms throughout the water column. Certain deep sea communities may even depend on these ephemeral feasts to survive in the desert of the abyssal plain, according to research by our colleagues at the Monterey Bay Aquarium Research Institute (MBARI).

This weekend’s salp bloom is a jiggly reminder of the vast community of gelatinous drifters—the gelata—that drift in the open ocean, connecting the surface to the deep and adjusting the Earth’s energy flow, unseen by most until a chance encounter on the shore.

Photo: Charles Schrammel
Gif: Alison Smith

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