The scientific vessel AGS-61 “Cabo de Hornos” was deployed on January 16 to the Antofagasta Region to collect substantial data on the composition of this sector of the ocean and the seabed at a depth of more than five thousand meters. This operation, called IDOOS, had as its main objective to explore the Atacama Trench, a deep depression originated by the meeting of two tectonic plates. This point is also the deepest section of the south-eastern Pacific, located between Taltal and the south of Antofagasta.
The studies were carried out by a team of scientists from the Millennium Institute of Oceanography (IMO), from the University of Concepción, the Catholic University of Chile, the Catholic University of Valparaíso and the University of Antofagasta. In addition, there was support from the Oceanographic Instrumentation Centre (CIO) and the presence of two German researchers from the Helmholtz Centre for Ocean Research in Kiel (GEOMAR). All these activities were carried out within the framework of an agreement between the National Agency for Research and Development (ANID) and the Chilean Navy, through the “Cabo de Hornos” (Cape Horn).
Scientific work
According to IDOOS Chief Scientist and IMO professional, Nadin Ramírez, “the main mission consisted of downloading data from five geophysical sensors located on the seabed, of which two were recovered. In addition, four deployments of a lander were carried out, an autonomous free-fall vehicle that has the capacity to reach the seabed, record video, capture organisms along with other hydrographic variables; the latter uses a Rosette sampling system and a drifting line. On this occasion, the lander reached 7,711 meters and collected information between the surface and 4,000 meters below sea level,” he said.
During the mission, data were collected on the pressure, temperature and inclination of the seabed, as well as physical and chemical parameters of the sea: salinity, temperature, oxygen, current speed and nutrients; and biogeochemical measurements, i.e. particle flows in the water column, chlorophyll concentration, etc. In addition, the lander managed to collect marine species that inhabit the bottom of the trench.
The autonomous vehicle used acoustic communication via modems and transducers, which allows it to communicate and command the release of weights so that the equipment can surface. To deploy the hydrographic instrument, winches from the scientific vessel “Cabo de Hornos” were used.
Use of data
Data collected from pressure sensors can measure vertical displacements of the ocean floor, which helps to understand the movement of tectonic plates and thus better understand the seismic cycle and the generation of earthquakes.
Sampling allows us to understand the properties of the water column, which is useful for studying the conditions in which different marine organisms live and the oceanographic dynamics that determine the functioning of the trench.
For Nadin Ramírez, “understanding the generation of earthquakes and tsunamis is a key issue both at a scientific level and in contingency planning for natural disasters. This is extremely useful for generating models capable of predicting these events with greater precision,” he said.
It should be noted that IDOOS is a work carried out by the scientific vessel “Cabo de Hornos” through an agreement between the National Agency for Research and Development (ANID), which promotes the development of marine sciences in the form of financing for ship days, both through direct agreement with the Navy for the use of the AGS-61 “Cabo de Hornos” and for the rental of a scientific vessel.