Paradox Of The Plankton - Blog Posts

THE PARADOX OF THE PLANKTON EXPLAINED BY COMPUTER SIMULATION

The paradox of the plankton results from the clash between the observed diversity of plankton and the competitive exclusion principle, which states that, when two species compete for the same resource, ultimately only one will persist and the other will be driven to extinction. With phytoplankton this is different, despite the limited range of resources, as is light, nitrate, phosphate, silicic acid, iron, a large number of species coexist, all competing for the same sorts of resources.

Now, a new math model explains such biodiversity. To understand this paradox researchers created a conceptual model for a theoretical community. Where each member of that community consumes one type of resource, and consuming it causes the production of exactly two new resources. Also, any new member could only survive if there is an open niche, or if it was better to exploit a resource than a current member. But with this computer simulation, researchers discovered that its simple rules led to a virtual community that, like the bacterial or phytoplankton communities, this hypotethical community was diverse and stable, and in fact became increasingly stable to as organisms diversified.

Resource competition and metabolic commensalism -where one organism benefits from the other without affecting it- drive a healty and diverse ecosystem. Researchers demonstrate that even when supplied with just one resource, ecosystems can exhibit high diversity and increasing stability.  Despite early stages where massive die-offs scenes occured, as time passed and community grew more stable, these became less common. Affortunately to phytoplancton species, two communities under ideal conditions can develop so differently from one another, without producing extintions.

Photo:  Gordon T. Taylor.

Reference: Goyal and Maslov, 2018. Diversity, Stability, and Reproducibility in Stochastically Assembled Microbial Ecosystems, Physical Review Letters