Influence of temperature and nutrient supply on the biogeochemical function and diversity of ocean microbes

Voyage summary

Research voyage to the east coast of Australia to study ocean microbes.

Microbes drive ocean biogeochemical cycles and regulate Earth’s climate yet are poorly represented in ocean-climate models. This project will use state-of-the-art cell sorting and molecular analysis techniques to gain a deeper understanding of microbial diversity and nutrient utilisation in waters influenced by Australia’s warming and strengthening East Australia Current (EAC). This research will provide managers and industry with more accurate insight into the effects of ongoing ocean change on the delivery of essential ecosystem services in eastern Australian waters.

One supplementary project is included on this voyage:

• Natural iron fertilisation of oceans around Australia: Linking terrestrial dust and bushfires to marine biogeochemistry (Dr Andrew Bowie, UTAS): Project to sample and conduct experiments on atmospheric particles containing terrestrial dust, bushfire smoke and anthropogenic emissions that are transported from Australia to its surrounding oceans.

Voyage impact

This voyage has provided a better understanding of the composition of microbes in relation to natural gradients of temperature and nutrients, and how microbes adapted to warm tropical conditions in north-eastern Australian waters change in structure or function as they are transported southward into temperate regions.

Zooplankton were found to be more abundant in cool water, including cyclonic eddies, and that these oceanographic features influence in the development of commercially important fish. Data collected will help to better understand this critical foodweb link. A program of research was also commenced that includes exploring the ocean microbiome, and understanding the links between oceanography and the marine foodweb, including larger consumers such as penguins.

Primary ocean productivity was mapped at unprecedented spatial resolution. Seafloor surveys during the voyage identified previously unknown underwater mountains and accurately determined the location of a shallow reef south of Montague Island.

Research resulting from this voyage will provide managers and industry with more accurate insight into the effects of ongoing climate change on the delivery of ecosystem services in eastern Australian waters. This information is essential to safeguard the biodiversity of our oceans, as well as the food and livelihoods of the people that depend on them.