Thursday March 21, 2024
PhysOrg —
A huge fraction of global flows of carbon and other nutrients pass through marine microbes. Little is known about their causes of death, however. This information determines where those nutrients will go.
Recent work on microbial death via viral lysis and protistan predation is helping close the gap, but there remains a missing source of microbial mortality. Anne Thompson from Portland State University and colleagues explore the role played by salps, pelagic tunicates that feed by pumping seawater through mucous mesh nets, filtering out and capturing particles such as preferred microbes.
Salps send the carbon in microbes to the deep sea as sinking fecal pellets—or to predators of salps such as seabirds and sea turtles. The authors conducted SCUBA dives to characterize salp predation in the vast oligotrophic North Pacific Subtropical Gyre, an area dominated by small-cell microbes, especially the very small Prochlorococcus.