Cal-San Diego study: Jellyfish-like creature linked to ocean carbon absorption

New research has highlighted the importance of a species of jellyfish-like creatures called salps, which feed on microscopic plants called phytoplankton in the ocean. The ocean plays a crucial role in absorbing large quantities of carbon dioxide in a process called carbon export, which is essential to combatting climate change, according to a news release. 

The new study indicates that a five-fold increase in carbon absorption can be linked to the prevalence of salps in the uppermost ocean, which ranks as one of the highest rates globally. The study, published in the journal Nature Communications, was led by Moira Décima, a zooplankton ecologist at the University of California San Diego's Scripps Institution of Oceanography.

“It can shift an ecosystem that has been fairly low in carbon export into being very efficient at delivering carbon to depth,” said zooplankton ecologist Moira Décima of the University of California San Diego’s Scripps Institution of Oceanography.

The process is straightforward. When salps bloom, or reproduce at exponential rates, they eat large amounts of phytoplankton. Their feces contribute to carbon export into the ocean environment, sinking rapidly and thus avoiding being consumed or microbially degraded in the upper ocean. This sinking means that the carbon-rich particles are less likely to return to the atmosphere and, instead, become sequestered for relatively long periods of time, becoming an efficient way of delivering carbon to depth. 

The researchers noted that salps can increase carbon export up to eight-fold with an average of a five-fold increase and that the effect is the same regardless of the type of water mass or phytoplankton community. 

While salps are not always present in high numbers, they can have significant impacts on carbon export and the food web, in general, when they are. 

The Southern Ocean has documented a substantial increase in salp abundance and, if the trend continues, important changes could be expected in areas where salp blooms are recurrent, according to the researchers.

Before launching the Salp Particle expOrt and Ocean Production (SalpPOOP) study, Décima saw salps as net-clogging pests that interfered with collecting crustaceans such as krill. 

However, she currently notes that salps are fascinating creatures that reproduce both sexually and asexually, creating a gelatinous soup within a few days during asexual reproduction. Salps are chordates, and although they look like jellyfish, they have a nerve chord similar to that of vertebrates. 

The research highlights a process by which carbon dioxide is removed from the atmosphere, converted into a solid form, and sequestered into the deep ocean, mitigating the effects of fossil fuel use and other activities contributing to climate change.