Scientists recovered a sediment trap, which provided autumn and early winter data; a time when there is usually no research on the white continent. The records obtained are considered unique.
The sediment trap is a cylinder that captures particulate matter that falls over an area of the seabed over an interval of time. © Paulina Möller.
Andrea Navarro, IDEAL Center. In the summer of 2019, a group of Chilean and foreign scientists arrived in South Bay, Doumer Island, Antarctica, to install a monitoring system that would allow them to obtain data for twelve months on the physical, chemical and biological characteristics of the water in depth. With this they could study the effect of the contribution of fresh water produced by the melting of glaciers in Antarctic bays.
These are researchers from the Center for Dynamic Research on High Latitudes Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh) and the Institute of Marine Sciences (ICM-CSIC) of Barcelona, Spain, who managed to recover after a year, in February 2020, a sediment trap, an oceanographic instrument that was submerged 200 meters deep. The rescue was carried out within the framework of the 56 Antarctic Scientific Expedition (ECA) organized by the Chilean Antarctic Institute (INACh).
The sediment trap is a cylinder that captures particulate matter that falls over an area of the seabed over an interval of time. The information it provides helps to quantify the flow and type of particles in the water column. Scientists chose South Bay for its installation, because it is an area that has great glacial and oceanic influence and, therefore, represents very well the polar environmental conditions. In addition to this, it is found in the Antarctic Peninsula where the effect of global warming is more evident than in many regions of the world.
The records obtained are of particular relevance because most of the oceanographic scientific work in Antarctica has been carried out in open water. However, there is little knowledge of the flow of particles over annual cycles in coastal systems and the potential impact that the retreat of glaciers, caused largely by global warming, will have on them.
Although the original plan contemplated that the sediment trap would collect samples throughout the year, it did so only in the first semester, specifically between February and July 2019. This because the lithium batteries were depleted earlier than expected.
The records obtained are of particular relevance because most of the oceanographic scientific work in Antarctica has been carried out in open water. © Paulina Möller.
“Despite the batteries’ problem, it is positive news because we obtained records of all the autumn and the beginning of winter, a season which it is hardly sampled in Antarctica. South Bay is an area where melting ice is rapidly changing. From this perspective, this data set is very valuable and unique because it represents a season that has been little studied,” explains ICM-CSIC researcher and rescue leader, Dr. Enrique Isla. “Once we analyze the samples, we hope to find information to help us better understand how this ecosystem behaves in the transition period between summer and winter, when the biological machinery begins to slow down its production and dynamic rate,” he adds.
Equipment corrosion
Although the sediment trap was successfully rescued, the researchers had to overcome their own setbacks of carrying out scientific activities at sea. The anchor in which the oceanographic instrument was installed also had temperature, salinity and oxygen sensors and a carbon dioxide pressure sensor.
One of the shackles that held this equipment together to the main anchor line was completely destroyed due to corrosion. As a result, the devices were detached and, therefore, valuable data that would help to understand the dynamics of the marine ecosystems of the Antarctic bays was lost.
“Despite the loss, we will try to anchor in the following 2021 summer campaign a new set of sensors that allows us to report on the role of photosynthesis in carbon absorption by coastal environments in Antarctica,” concluded the oceanographer from the IDEAL Center, Dr. José Luis Iriarte.