Glaciers are known to be a source of phosphate, silicon and iron, nutrients that are essential for the growth of the marine algae that form the basis of the food chain in the oceans. However, the extent to which these nutrients reach the ocean, and what happens when they get there, isn’t fully understood.
The two-week trip expedition to the fjords, an important transition zone between the meltwater streams and the oceans, will be the first time that scientists have tried to track these biologically important elements from their source under the glaciers into the oceans.
Principal scientist on the expedition, Dr Kate Hendry, from Bristol’s School of Earth Sciences, said: “With the world’s glaciers melting and retreating at an ever-increasing rate, it’s vital that we understand the consequences of this meltwater on the balance of nutrients and, so, biological production of algae, which form the basis of the food chain in the oceans.
“The holistic approach that we’re taking is especially novel as it will build a complete picture of the whole nutrient system based on physics, chemistry and biology of the system, from the freshwater inputs to the open ocean.”
The expedition is part of the European Research Council (ERC) funded project, ICY-LAB. It involves scientists from Cardiff University, Imperial College London, and the University of Alabama as well as members of the University of Bristol.
The project’s main aim is to provide unprecedented insights into nutrient cycling, biomineralization, and the taxonomy and biogeography of siliceous organisms in an ecologically important region of the North Atlantic.
This trip builds on the work carried out last year when Dr Hendry led an international ocean-going expedition to the Labrador Sea and coastal Greenland as part of the RRS Discovery cruise DY081, to investigate glacial meltwater and marine cycling in the oceans.
That trip saw the crew collect and filter approximately 28,000 litres of seawater over the course of one week, analysing more than 50 metres of marine sediments and 1,551 biological specimens extracted from an area over twice the size of Wales.
“Thanks to the Bristol Glaciology Centre, we already have some idea of how important glaciers are in releasing these important nutrients,” adds Dr Hendry. “A big question is, though, whether these nutrients make it into the coastal seas and out into the open ocean. The data we captured last year already revealed the impact of these meltwaters all the way out into the offshore currents. However, it’s not a straightforward picture – with different chemical elements behaving in different ways – which is why we need to connect the dots with a better understanding of the nearshore processes.”
While at sea, the team will filter hundreds of fjord waters for the project, using a wide range of novel analytical and geochemical techniques. This will include some isotopic analyses used to track weathering rates and reactions. The ship will also utilise an array of sensors to track changes in water temperature, salt-levels, oxygen, organic matter and algae.
Source: University of Bristol