Vast (but avoidable) underestimation of global biodiversity

Area of Science:

• Microbiology
• Biodiversity Science
• Ecology

Background:

• The total number of species on Earth remains a significant scientific uncertainty.
• Recent estimates suggest fewer than 2 million prokaryotic species exist.
• Prokaryotes, including bacteria and archaea, are crucial to global ecosystems.

Purpose of the Study:

• To challenge the low estimates of prokaryotic species diversity.
• To propose a significantly higher range for the number of prokaryotic species.
• To highlight the potential underestimation of microbial biodiversity, particularly bacteria associated with hosts.

Main Methods:

• This study is a formal comment, presenting a theoretical argument and re-evaluation of existing data.
• It critically analyzes the methodology and conclusions of a recent study estimating prokaryotic species numbers.
• It synthesizes ecological and microbiological principles to support an alternative hypothesis.

Main Results:

• The study argues that current estimates of prokaryotic species diversity are likely too low.
• It posits that the actual number of prokaryotic species could be in the hundreds of millions or even billions.
• The majority of these species are hypothesized to be bacteria, predominantly associated with insects and other animals.

Conclusions:

• There is a substantial underestimation of global prokaryotic biodiversity.
• The vast majority of Earth's species may be microbial, particularly host-associated bacteria.
• Further research is needed to accurately quantify microbial diversity and its ecological significance.