eLife reports a study that trade-offs between the benefit of colonizing new particles and the danger of being destroyed by predators allow diverse populations of marine microbes to exist together.
Microbial foraging in patchy environments, where resources are divided into particles, plays a crucial role in natural environments. In oceans and freshwater systems, bacteria and microbes can intercede with particle surfaces in various ways: some only colonize them for short periods, while others form long-lived, stable colonies.
Scientists have long wondered about the greater-than-expected diversity of microscopic creatures in oceans, a phenomenon known as the "plankton paradox." While researchers have begun to investigate the factors that support so many different types of plankton, many questions remain about the more plentiful ocean microbes that exist on floating particles.
"We wanted to look at the role that dispersal strategies play in the successful coexistence of different microbes living on the same set of particles," says co-first author Ali Ebrahimi, who completed the study while he was a postdoctoral fellow at the Massachusetts Institute of Technology (MIT).
Ebrahimi and the team discussed how different dispersal strategies may aid marine microbes exist in this way. They found that differently navigating the trade-offs between growth and survival may enable microbes to flourish together.
Organisms who remain on a single particle for longer have greater chances to multiply. However, they are at greater risk of being wiped out by a virus or other predator capable of infiltrate whole particles. On the other hand, microbes that hop between particles have less chance to multiply, but also have a greater likelihood of experiencing a mass mortality event. One strategy over another may be based on different environmental conditions.
Microbes that hop rapidly between them will have a greater chance of survival, according to the co-first author Akshit Goyal, a MIT professor of physique. "But when particles are harder to come by, bacteria that stay put will have an advantage."
Along with these two factors, the group found that coexistence may remain stable in the face of changing environmental conditions, such as algae blooms, increasing growth, and increasing numbers of predators, favoring mortality. Together, these factors increase the likelihood that populations with diverse dispersal strategies may live together.
"Our work focused on the relationship between dispersal and mortality in the ocean, but there''s still a lot more going on in these environments," Goyal concludes. "Future research might provide important new insights on how environmental changes might impact these small minority communities and, in turn, their wider marine ecosystem."