Friday January 20, 2023
Eos —
Salps are transparent, tube-shaped jellies well known for their propulsive jetting movements. According to new research, they also take quite a bit of carbon along for the ride.
Populations of these gelatinous zooplankton—part of the subphylum Tunicata, or sea squirts—are episodic and patchy. Sometimes, though, they “bloom” and form huge aggregations. En masse, their feces, daily migrations up and down the water column, and sinking carcasses sequester carbon into the deep sea.
In a recently published study, Steinberg et al. show that salp-related carbon sequestration is especially prominent in retentive or low-export food webs. The authors sampled a full suite of salp-related carbon export processes during a 2018 Salpa aspera bloom in the subarctic northeastern Pacific Ocean.
Aboard R/V Roger Revelle and R/V Sally Ride, the researchers deployed cameras and cast nets up to 1,000 meters deep during day and night. They lugged up salps and other zooplankton, sorted and weighed their catch, and trapped sinking salp feces. They also conducted onboard experiments and incorporated all of their data into a model to approximate carbon export in the study zone. The team repeated this process across three 8-day sampling cycles.