Researchers on a five-week voyage will investigate the vital role of tiny animals called zooplankton in ocean ecosystems and carbon storage.
Zooplankton, which eat microscopic plant-like organisms called phytoplankton, are thought to be the most numerous multi-celled animals on Earth - vastly outnumbering insects.
A team of researchers set off from Rekyavik in Iceland on Friday (6 September) on the Royal Research Ship James Cook, exploring the Iceland basin and north-east Atlantic before docking in Cardiff on 13 October.
The voyage is part of the BIO-Carbon programme, which aims to improve our understanding of the role of marine life in storing carbon in the ocean.
"Zooplankton are fascinating and beautiful creatures - although many are too small to be seen with the naked eye," said Professor Daniel Mayor, from the University of Exeter.
"While phytoplankton are the primary producers in the ocean - turning sunlight and carbon dioxide into carbohydrates and oxygen - zooplankton provide the crucial next step by preying on them.
"This is the basis of the wider food web, including everything from fish to whales, and in this process vast quantities of faecal matter are produced. This then falls as 'marine snow', locking carbon into the deep ocean for hundreds of years.
"We want to learn more about how these processes work, and how changing conditions on our planet might affect them.
"If we want to understand how the ocean works today and how it might work tomorrow, we need to understand the small stuff that underpins it all - and that's what we're doing."
At present, the ocean absorbs about a quarter of carbon emitted by human activities. Land ecosystems absorb another 30%, while the rest goes into the atmosphere where it contributes to global warming.
The team on the RRS James Cook includes researchers from multiple institutions and disciplines, taking a wide range of observations using technology ranging from floats and gliders to satellites.
The Exeter researchers on the voyage are Professor Mayor, Dr Franki Perry, PhD student John Duffy and Josephine Tod (a lab technician and early career researcher).
Tod said: "I will be joining the BIO-Carbon cruise to operate a plankton imaging instrument called the Flowcam.
"This cutting-edge technology allows us to visualise the results of plankton experiments conducted with live microscopic animals collected whilst at sea, with the aim to help us better understand their biological processes and role within marine systems.
"Typically, I analyse the samples after they have been brought back to the laboratory, so being there in person and experiencing life aboard a scientific research vessel is a fantastic opportunity."
