Scientists Map Great Barrier Reef Microbiome and Find Hundreds of New Species

For the first time, researchers have peered into the microscopic depths of the world’s largest coral reef system to map its invisible inhabitants. Analysing DNA from seawater samples collected across 48 different reefs, an Australian scientific team has documented more than 800,000 microbial genomes. The massive undertaking, published in the journal Nature, reveals a hidden ocean world containing over 500 new bacterial species and hundreds of thousands of distinct viruses.

Overcoming Ocean Chaos with Long-Read DNA Sequencing

Mapping a marine microbiome is notoriously difficult. Ocean currents constantly mix closely related microbes together, and many organisms native to low-nutrient marine environments possess low levels of G and C, two of the fundamental bases forming the DNA double helix. These biological hurdles long kept researchers from fully sequencing marine microbial populations.

To bypass these challenges, scientists utilized advanced long-read sequencing technologies. Dr Steven Robbins, a team lead at the University of Queensland and the study’s first author, explained how the technology transformed the work.

“What was a puzzle with tens of thousands of pieces becomes a simple puzzle with far fewer pieces.”

Dr Steven Robbins, team lead at the University of Queensland and first author on the paper

The resulting data forms the newly established Great Barrier Reef Microbial Genomes Database, which is now open to researchers worldwide. According to the Australian Institute of Marine Science, the platform will complement long-term monitoring programmes that have tracked the reef for over forty years.

Great Barrier Reef Microbiome Survey Identifies Hundreds of New Species

New Species and Viral Discoveries in Reef Waters

The research identified 5,283 different bacterial and archaeal genomes representing 876 distinct species, roughly two-thirds of which were previously unknown to science. Furthermore, the team documented 362,802 different viruses, including Crassvirales.

“These microbes are important. Microalgae produce most of the oxygen we breathe and underpin food chains in the open oceans.”

Dr Yun Kit Yeoh, senior research scientist at AIMS and senior author of the paper

Those microalgae are consumed by krill and zooplankton, which in turn feed everything from small coral polyps to massive whales, anchoring the marine food web.

Using Microbes as a Diagnostic Tool for Marine Health

Beyond cataloging invisible species, the database offers practical applications for conservation. Professor Philip Hugenholtz, a microbiologist at the University of Queensland and senior author of the research, emphasized the new diagnostic potential.

“Now, we can start to explore what makes a healthy reef microbiome and how these invisible communities respond to changes on the Great Barrier Reef such as bleaching, storms, sediment, fishing and other stresses.”

Professor Philip Hugenholtz, microbiologist at the University of Queensland and senior author of the study