I bet you have hardly heard of salps until now, and if you have, maybe you did not realize their vast importance in the ocean and the world! Keep reading to find out how awesome Salps are and how lucky we were to experience such an amazing event! Follow us for more updates and photos @MarissaCharters
A Day to Remember: Thousands of Salps
On Saturday, July 27th, 2024, while diving off Point Loma at our Strawberry Ledges dive site, we witnessed an extraordinary event: thousands and thousands of salp chains or aggregates.
@underwaterpaparazzi
But First, What Are Salps?
Salps are zooplankton, specifically planktonic tunicates. Their gelatinous bodies have a brain, central nervous system, and digestive system. Despite their jellyfish-like appearance, they are more closely related to humans than jellyfish.
ASex-y Salps!
Fascinatingly, salp chains or aggregates are formed via asexual reproduction, and each salp body in the chain is a genetic clone of the first. After the aggregate is formed, a single salp body will break off, release an embryo, form testes, and move on to fertilize an entire aggregate chain. This super-efficient reproductive cycle allows them to respond quickly to favorable environments rich in nutrients, making them some of the fastest-growing multicellular animals on Earth! (3)
Food Supply - The Little Guy (or Gal) for the Win!
Salps subsist on phytoplankton. They use jet propulsion to move around while simultaneously filter feeding. Phytoplankton blooms in the presence of dissolved atmospheric CO2 and sunlight via photosynthesis, producing glucose and O2.
Phytoplankton produce more than 50% of the world's oxygen—more than the rainforests! These tiny, largely unseen and unrecognized organisms are the powerhouse of the ocean. Often, it is the overlooked little guy (or gal) that makes the most impact.
POOP - An Overlooked but Hugely Important Process!
When a salp consumes the small but mighty phytoplankton, it filters large amounts of phytoplankton-filled water, compacting the tiny phytoplankton into a "fecal pellet" that consists largely of organic carbon. After the salp poops, the fecal pellet sinks to the seafloor and slowly decomposes, releasing nutrients and CO2 back into the ocean. (2)
When salps die, their bodies, made of organic carbon, sink and perform the same role as their poop, slowly decomposing and releasing nutrients and CO2 back into the ocean.
Why is This Important? - Putting it All Together
This cycle—phytoplankton uptaking dissolved atmospheric CO2 and water from their surroundings, using energy from photosynthesis to produce O2 and glucose, and the salps consuming phytoplankton and creating organic carbon that sinks to the seafloor and slowly releases nutrients and CO2 back into the ocean—is called the Biological Carbon Pump (BCP). (3)
The Biological Carbon Pump is responsible for scrubbing the atmosphere of excessive CO2. Without it, our atmosphere would be dangerously high in CO2. (3)
How Lucky Were We?
Extremely! On a nearly all-ladies trip, Allison Vitsky, Jami Feldman, Melissa Foo, and Andy Sallmon jumped in the water not realizing they were about to experience a once-in-a-lifetime dive!
Salps migrate from the farthest depths of the ocean floor to the surface every night. This massive movement of plankton is called "vertical migration." Traveling thousands of feet each night and day, they participate in the largest migration in the world. Every. Single. Day! Somehow, perhaps with the incoming tide as Allison suggested, and the cold 51°F water allowing for a salp explosion, the salp chains showed up at Strawberry Ledges en masse in the middle of the day!
You too can have a once and a lifetime experience with us! We just added more trips to the schedule! You never know what you are going to see! Come join us!
Our experience even made the evening news! CBS Channel 8 San Diego did a fantastic job putting together a piece about our experience.
You can check out more awesome videos and photos from that day by visiting our customers' Instagrams: @underwaterpaparazzi, @Melissa_Foo_, @andysallmon, and @diveintothepink.
@Melissa_Foo_
1. Dawczynski, M., Cacabelos, R., Escaravage, V., Malzahn, A. M., & Mittermayer, F. (2023). The importance of tunicates in marine ecosystems. *National Center for Biotechnology Information*. Retrieved from [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10078299/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10078299/)
2. The Marine Detective. (n.d.). Tunicates. *The Marine Detective*. Retrieved from [https://themarinedetective.com/category/marine-invertebrates/tunicates/](https://themarinedetective.com/category/marine-invertebrates/tunicates/)
3. RAPID. (n.d.). Biological Carbon Pump. *RAPID*. Retrieved from [https://rapid.ac.uk/abc/bg/bcp.php](https://rapid.ac.uk/abc/bg/bcp.php)
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