Life in the oceans evokes spectacular images of colourful coral reefs, dolphins at play and majestic creatures of the deep. However, far more numerous than visible sea life, millions of vastly diverse microbes reside in every litre of seawater and dominate ocean ecosystems from the tropics to the poles and from the surface to the deepest realms. Researchers studying ocean life that is invisible to the naked eye say “charismatic megafauna” such as fish and marine mammals are merely the tip of the iceberg when it comes to the ocean’s biodiversity.
Scientists from 18 Australian universities and research institutes have come together to reveal the diversity and dynamics of the unseen microbial multitudes that keep our oceans healthy. Writing in the Nature journal Scientific Data, the team reports on an enormous genetic database that tracks microbes over space and time in Australian marine environments.
“Microbes in the ocean are possibly the most important organisms for maintaining our world as a healthy, habitable planet. They constitute over 90% of the ocean biomass, produce half the oxygen we breathe and provide the food for all marine life. Similar to the links between human health and the human microbiome, ocean health is largely controlled by its microbial inhabitants,” said lead author, Dr. Mark Brown from the University of Newcastle.
This ongoing project was carried out through funding from the Australian Research Council (ARC), the Commonwealth Scientific and Industrial Research Organisation (CSIRO), and the National Collaborative Research Infrastructure Strategy (NCRIS) via Bioplatforms Australia (Bioplatforms) and the Integrated Marine Observing System (IMOS). The project was developed from 2012 to address the worrisome lack of datasets describing microbial communities in the ocean and how they change over time. Such information is critical to our ability to predict potential effects of changing climate and human activities on our oceans and the environmental services they provide.
"This project represents a sea change for marine science in Australia,” said Bioplatforms’ Dr. Anna Fitzgerald. “It fosters collaboration among the top marine researchers around the country, enhanced by access to world-class infrastructure. Molecular techniques and big data form the modern language of environmental science. This dataset establishes a molecular baseline that will support the development of the next generation of monitoring tools to manage our marine assets.”
The large collective of scientists from around Australia working to fill in the gaps in our knowledge of the ocean’s microbial diversity are collecting monthly samples from seven marine National Reference Stations operated by IMOS. These include Darwin Harbour, the Yongala wreck inside the Great Barrier Reef lagoon, North Stradbroke Island off Brisbane, Port Hacking off Sydney, Maria Island off Tasmania, Kangaroo Island off Adelaide and Rottnest Island off Perth. The scientists collect microscopic marine dwellers by filtration methods similar to those used to purify drinking water, except they keep the part with the microbes in it, not the sterile water. The genetic material extracted from the filters is then sequenced using high-throughput sequencing technology, providing a snapshot of the DNA blueprint of the microbial inhabitants of each sample. The dataset tracks over 200 million records of more than 175,000 unique species of microbes. It is the first data release from the ongoing initiative, in which samples are being collected over 80,000 km of ocean voyages covering most of Australia’s coastline and into the Southern Ocean.
“This is a very exciting project,” said Tim Moltmann, Director of IMOS. “It has catalysed an unexpected collaboration between field-based marine environmental sampling, and lab-based sequencing and bioinformatics. This coupling has created a research dataset that we simply could not imagine having just a few years ago. It has opened our eyes to future opportunities for bringing these techniques into Australia’s marine environment, which is vast, valuable, and changing rapidly.”
By comparing seasonal dynamics at these strategic sites around Australia, the team will learn what factors modulate ocean productivity. For example, the newly released dataset is being used to understand how complex regional dynamics, such as the East Australian Current, shape microbial diversity and ecosystem productivity now, and how things might change in the future. Dr Martin Ostrowski of Macquarie University and co-author on the paper said, “These data will now allow us to predict where organisms will live in the future, and what functions they will carry out. The primary production and carbon use by marine microbes determines how much food is provided to the rest of the food chain, so our forecasts will be incredibly relevant not just to scientists but also to industries such as fisheries and tourism.”
The paper’s senior author Dr. Lev Bodrossy of CSIRO Oceans and Atmosphere said, “The work has delivered a set of data and new knowledge on marine microbial processes that is unparalleled anywhere else in the world and has been the catalyst for a multi-institutional collaboration that has dramatically pushed this research discipline forward and expanded its impact on Australian marine science. The value of an observing network increases exponentially with time so it is now crucial we maintain our sampling and expand our observations into the future”.
To read the full paper: https://www.nature.com/articles/sdata2018130