The project is comprised of many parts, one of them is to look at the sediments found at the seafloor. Throughout the trip a special piece of equipment, called a MegaCorer, is sent down to the bottom of the sea to depths of up to 3500m. Here it sinks into the soft sediments on the sea floor and fills up tubes creating cores. When it returns the cores are taken out of the tubes sliced into thin sections which look like mud pies! They are then frozen at -80°C and then they are ready for analysis back in the UK.
These sediments contain parts that we can see using our eyes or a microscope such as shells, mud, sand and stones. They also contain lots of small parts, some of these are food for small animals like zooplankton that sit at the bottom of the food chain.
We look at the sediments to determine the original source of the ‘food’ component within them. It could have originally been on land around the ocean and has been washed in by rivers or erosion of the coast. But, it could also have been made my marine life, little shells that are left behind when an animal dies.
We use isotopic signatures to better understand how much the land contributes to the oceanic sediments and how much the marine pool does also. Initially this is done on a bulk level, meaning all parts of the sediment are analysed, this is a useful indicator of the origin on the material but only gives an overview. To understand how the food chain is impacted we have to look at the part of the sediment that animals can eat. So we look at compounds called amino acids, these are the building blocks to make proteins that are found in everyday food like meats and green vegetables. By analysing individual amino acids we can see where they have come from and potentially if they have been eaten prior to being dumped at the bottom of the sea.
This is important in the Arctic Ocean because increasing temperatures in the region mean there is more material being delivered from the land. The fate of this material is still poorly understood but collecting these sediments should help us to build a story of what happens to it.