Scientists prepare to monitor Atlantic Ocean

The circulation patterns of the Atlantic Ocean could be undergoing transformations that could potentially interfere with the global climate. To understand this phenomenon, an international group of scientists will install a series of monitoring instruments along a line that extends from South America to Africa.

By Fábio de Castro

Agência FAPESP – The circulation patterns of the Atlantic Ocean could be undergoing transformations that could potentially interfere with the global climate. To understand this phenomenon, an international group of scientists will install a series of monitoring instruments along a line that extends from South America to Africa.

Brazil will play a significant role in the task, which is part of the international South Atlantic Meridional Overturning Circulation (SAMOC) project: all the instruments on the western end of the project will be installed and operated by researchers from a thematic project financed by FAPESP and coordinated by Professor Edmo Campos of the Universidade de São Paulo’s Oceanographic Institute (IO/USP).

The thematic project was approved at the beginning of December as part of the FAPESP/FACEPE/ANR cooperative agreement, which is anticipating collective calls for research proposals involving FAPESP, The Pernambuco State Research Support Foundation (FACEPE) and the French National Research Agency (ANR).

In addition to Campos’ coordination on the Brazilian side, the project will be coordinated from the French side by Professor Sabrina Speich of the Université de Bretagne Occidentale’s European Institute for Marine Studies (IUEM).

According to Campos, the goal of the SAMOC project is to monitor the circulation of the South Atlantic’s waters. Certain observations have indicated that these patterns of circulation have been changing. 

“These circulation patterns are, ultimately, one of the mechanisms that control the planet’s climate. The goal of this international group is to monitor the South Atlantic to understand how it is behaving today and, eventually, how it will behave in the future with the changes being identified,” Campos told Agência FAPESP.

Many areas of the Atlantic Ocean are already being monitored by the SAMOC project and by different institutions, including the National Oceanic and Atmospheric Administration (NOAA) in the United States and others from Brazil, Argentina, South Africa and Europe. According to Campos, these initiatives are still quite tenuous but have the potential to become a permanent oceanic monitoring system in the future. 

“Until now, Brazil had participated in this set of initiatives merely as support. But with the project we are beginning now, we will be able to contribute significantly to the consolidation of the monitoring system,” he stated.

Campos says that if the physical characteristics of oceanic circulation are observed, it can be seen that the most intense activity occurs near the continents, especially on the west side. For this reason, it is important that the instruments be distributed along a line that extends from one continent to the other and with a greater density at the two extremes.

“The Atlantic Ocean’s circulation pattern works as a fundamental part of the mechanism that distributes heat in many parts of the planet. If there is a change in this pattern, we will have a climatic response on both the regional and global scale. This pattern also responds to atmospheric changes,” he explained.

Campos says that the instruments, which include speed, pressure, temperature and salinity sensors, will be submerged—meaning fixed to the sea floor—from South America to South Africa along a line that runs at 34.5 degrees south latitude. The Brazilian team will be responsible for the whole western portion of the monitoring network. The French team, along with the South African team, will be responsible for the eastern part. The North Americans from NOAA and the National Science Foundation will be responsible for the middle section. 

“FAPESP is financing a number of instruments whose function is to measure the transport of volume, meaning the velocity of the waters integrated in a determined section. The goal is to evaluate how much fluid is being transported and how much heat and salt this flow carries with it. We basically want to know how much heat is being transported along this line toward the north. Small changes in this heat transfer can unleash radical changes in the climatic balance,” he explained. 

Today, said Campos, it is known that the global climate is strongly influenced by the amount of heat that the South Atlantic transports to the North Atlantic. “For this reason, we have to measure the velocity, the temperature, the salinity and a series of parameters that will allow us to understand how the dynamics of this circulation are being changed,” he stated.

Mission for the Alpha Crucis

According to Campos, the installation of the equipment in the Brazilian section of the project will be finished by the end of 2012 by the oceanographic vessel Alpha Crucis, purchased with FAPESP funding and managed by USP. The instruments, he says, will be submerged to depths from 200 meters to 6,000 meters.

“The instruments will not transmit data in real time, so the ship will need to travel to them and recover data via sonar as well as perform maintenance. The instruments have acoustic modems, and the data are collected when the ship passes over them. Every two years, on average, it will be necessary to retrieve them to change their batteries and then submerge them again,” said Campos.

According to Campos, it is probable that the SAMOC project will represent one of the first large-scale uses of the Alpha Crucis. Without the ship, the operation would be limited by its need to use Navy ships, subject to a series of restrictions and making research very difficult.  

“Brazil has a tradition of seashore research only due to a lack of resources. Now, however, with the availability of the ship, we will finally produce oceanography of the highest international quality,” he said.