Reported by E. Isla; written during the Antarctic Scientific Expedition ECA55 (IDEAL-ICM, EDGE project) during his stay at the “Chilean Antarctic Scientific Base Yelcho”, in March 2019
The designated place for installation would be near the center of the bay, at a point about 240 m water depth. The line has a total of 190 m in length to leave about 50 m of space with the sea surface to reduce the risk of drag and loss of the line if a large ice floe passes over the mooring station. We hope that this won’t happen. The line is equipped with dissolved oxygen, temperature and conductivity (with which the salinity value can be obtained) sensors at different depths, a CO2 pressure sensor and a sediment trap about 50 m above the seabed to reduce the interference of the material that can enter the trap resuspended from the bottom of the sea and to better estimate the flow of material that arrives from the surface. This “rain” of particulate matter, also known as marine snow, carries with it a fraction of organic carbon and biogenic silica that is related to planktonic organisms living in the illuminated layer of the sea and these in turn, with the environmental conditions of the bay in which they developed. The idea is to maintain this mooring for several years to better describe inter-annual and intra-annual variations in particle fluxes towards the seabed and distinguish them from possible anthropogenic interference.
The investigation of an environment so close to the coast and its relationship with glacial melting is an unusual approach in Antarctica due to the logistical implications of these type of installations and the danger of loss due to the transit of ice flows and sea ice cover. We hope that, after a year, when we return to collect the instruments, we can find everything in good condition and later on, with the new samples, be able to better explain the relationship of changes in temperature and coastal glaciers with marine organisms.