The Polarstern on a previous Changing Arctic Oceans programme cruise

Introducing CACOON and PETRA

S. Hendricks 

PML will lead two new projects exploring the health of the Arctic Ocean. 

The Arctic Ocean is a rapidly changing environment, with rising temperatures leading to an ongoing decline in sea ice and shifting conditions for marine life. Despite the presence of important and complex ecosystems in Arctic waters, there are knowledge gaps in how the Arctic Ocean and its inhabitants will be impacted upon and respond to global climate change.

PML scientists will now lead two exciting projects, funded by the Natural Environment Research Council (NERC) as part of the Changing Arctic Oceans (CAO) programme, to further research Arctic Ocean ecosystems and the pressures they face.

CACOON (Changing Arctic Carbon cycle in the cOastal Ocean Near-shore) will examine the carbon cycle in the coastal ocean off the Arctic mainland, where a growing amount of freshwater – from permafrost thawing and increased rainfall - meets the marine environment, and ultimately how the Arctic Ocean’s integral processes will be affected by these changing conditions.

PETRA (Pathways and Emissions of climate-relevant TRace gases in a changing Arctic Ocean) will combine chemical and biological observations with modelling to investigate the impact of three stressors - ocean acidification, warming waters, and elevated irradiation - on the pathways and emissions of key trace gases in Arctic Ocean cycling. PML scientists will soon be on board the German Icebreaker, Polarstern, on a research cruise that will take them into the Fram Straits and the Greenland Sea.  

Dr Ricardo Torres, senior scientist at PML and lead for the CACOON project, said: “We are seeing significant changes to the global ocean as a result of climate change, and the Arctic is a region where these changes are happening faster than anywhere else in the world. However, this is also one of the most challenging regions to work in and observations of these changes are very difficult to obtain. Through a large international effort with Russian and German colleagues, we will collect valuable data and increase our knowledge of the role that the interaction of land and coastal seas have in our climate.

In CACOON we will study the impacts that increasing temperatures have on the transport and transformations of Organic Matter from the land to the ocean as a result of thawing of permafrost. This process liberates carbon that has been sequestered for centuries and has the potential to contribute to our changing climate in ways that are still not fully understood. By focusing on two large Siberian rivers (The Lena and Kolyma rivers) we will measure and model a very important component of the coastal arctic ecosystem, one that is especially vulnerable to the changing climate.”

Dr Andy Rees, senior scientist at PML and lead for the PETRA project, said: “PETRA is the result of a fantastic opportunity for teams from PML in the UK and GEOMAR in Germany to work together on an issue that is recognised as critical by international experts. We will use state of the art experimental approaches and computer modelling to investigate how environmental changes in the Arctic Ocean are affecting the atmospheric content of gases which play a large part in controlling our climate”

The two new projects join current PML CAO research that began in 2017: the DIAPOD project, exploring how warming influences the bottom of the Arctic food chain, and ChAOS, investigating how the thinning and retreating of sea ice under global change affects the seafloor ecosystem. 

Other recent news articles


Consortium submits plan to confirm South Wests status as global leader in ocean tech innovation

The Ocean Futures programme identifies key strengths in fields including marine autonomy, digital innovation and clean maritime.


‘Environmental Impact of Ships’ book available to buy

PML’s former CEO working with PML scientists have published the fascinating book ‘Environmental Impact of Ships’ , which is available to buy this London International Shipping Week.  


Widespread phytoplankton blooms in the Southern Ocean following Australian wildfires

A team of international scientists have identified widespread phytoplankton blooms in the Southern Ocean, from December 2019 to March 2020, following the Australian wildfires.