By Jonny Lupsha, Wondrium Staff Writer
When his country canceled all flights, an Argentinian man sailed home from Portugal, The New York Times reported. His voyage, which took 85 days, reunited him with his brother and father shortly after his father turned 90 years old. The ocean’s currents played a major role the whole way.
The Times article said that Juan Manuel Ballestero made the decision to sail home to Argentina from a Portuguese island very shortly after the initial lockdown. “Days after Argentina canceled all international passenger flights to shield the country from the new coronavirus, Juan Manuel Ballestero began his journey home the only way possible: He stepped aboard his small sailboat for what turned out to be an 85-day odyssey across the Atlantic.”
Ballestero, 47, could have waited out the lockdown on the island of Porto Santo, but he couldn’t stand the idea of spending such a frightening time away from his family, The Times reported. “A particularly painful aspect of this awful era has been the inability of an untold number of people to rush home to help ailing loved ones and to attend funerals.”
Ballestero found himself at the mercy of the Atlantic for nearly three months. Ocean currents affected his journey.
Two kinds of ocean currents circulate among the Earth’s waters. Currents near the surface get their directions from the wind, and so they’re aptly titled surface currents or wind-driven currents. Ocean currents deeper in the sea are called thermohaline currents.
“Most of us will never see a thermohaline current because they happen deep underwater, in the abyssal depths of our oceans, but they are profoundly important because they regulate the heat balance of our planet,” said Dr. Sean K. Todd, the Steven K. Katona Chair in Marine Sciences at the College of the Atlantic in Bar Harbor, Maine. “And so, we feel their effect every day.”
Dr. Todd said that the North and South poles are surrounded by water that’s constantly being cooled. Since water becomes dense as it cools, the cold water sinks and spreads to lower latitudes, and is always replaced at the poles by warm water. This cycle is called thermohaline circulation and affects maritime weather around the world.
Seafarers like Juan Manuel Ballestero experience the effects of thermohaline circulation in the temperature of the world around them and the density of the sea under their feet.
“The density of seawater is quite variable,” Dr. Todd said. “The three major factors that control density are temperature, salinity, and pressure, although pressure plays an almost negligible role because water is essentially incompressible. However, if you’re in hot areas where there is more evaporation than there is precipitation, the water will increase in salinity and so become denser.
“Paradoxically, in areas where it is cold enough to freeze water, you can also create saltier water because salt is often excluded when the ice lattice forms, a process called brine rejection.”
Dr. Todd said that in both of these instances, the denser water will sink to a point of “neutral buoyancy,” meaning it reaches a point where it has the same mass as surrounding water. Since this sinking process is a movement of water, it’s called a current. Since it revolves around temperature and salinity, it’s called thermohaline.
Masterful sailing can get someone across an ocean, but thermohaline circulation travels with them every step of the way. From Porto Santo to Argentina, Ballestero was at the mercy of oceanography.
Dr. Sean K. Todd contributed to this article. Dr. Todd holds the Steven K. Katona Chair in Marine Sciences at the College of the Atlantic in Bar Harbor, Maine. He received a Joint Honours undergraduate degree in Marine Biology and Oceanography from Bangor University in the United Kingdom and his master’s and doctoral degrees in Biopsychology at Memorial University of Newfoundland in St. John’s, Canada.