Diversity in many biological communities is a sign of an ecosystem in balance. When one species dominates, the entire system can go haywire.
Diversity in many biological communities is a sign of an ecosystem in balance. When one species dominates, the entire system can go haywire.
For example, the uncontrolled overgrowth of certain oceanic algae species causes toxic red tides that kill fish and other sea life, and sicken humans. On a more individual level, the human gut hosts a large community of different bacteria that is crucial for proper digestion and absorption of nutrients. Disruption of or imbalances in this bacterial community can cause a bloom in the growth of a toxic species, causing nausea, diarrhea and other illnesses. There’s an urgent need to understand how microbial community diversity is developed and maintained, especially as human activities change our external and internal environments.
Like all life, microbes require certain nutrients, such as sunlight, sugars or nitrogen sources, to survive and reproduce. Many microbe species’ nutrient requirements overlap, putting them in competition with each other. Much effort has been devoted to understanding how this competition influences microbial diversity when nutrients are steadily supplied. However, in nature, it’s quite common for the resources to be available only seasonally so that their supply is severely limited at least some of the time. For example, bacteria in the gut that live on sugars might find these abundant right after the human’s had a meal, and scarcer the rest of the time. Because each bacterial species is genetically unique, it will have its own particular strategy for using a given nutrient. Species with the most efficient strategies for using the available nutrients experience the best growth.
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Image via KC Huang, Stanford University.
