For oceanographer Emmanuel Boss, uncovering secrets underwater isn’t about finding buried treasure or unearthing sunken ships.
Using specialized sensors, Boss studies the effects of particles on the underwater light to understand what lies beneath. His research focuses on what marine optics can tell us about what’s in the ocean and how those particles — most no bigger than a few micrometers — impact processes in the water, as well as in the global system.
Knowing what’s below the surface throughout the oceans is needed in researching the role of the water in cycling elements such as carbon that are fundamental in understanding Earth’s climate and monitoring climate change. With marine optics, Boss and other scientists use satellite ocean color imagery to study ecological processes, such as what species of phytoplankton dominate, and biogeochemical processes, including how fast carbon is fixed by phytoplankton into organic material.
“There are many events in the ocean that are happening that we’re completely missing using current sampling techniques,” says Boss, an associate professor in the University of Maine School of Marine Sciences. “With data from new systems, potentially we can start accounting for those.”
Most recently, by using novel robotic technology he equipped with optical sensors, Boss has been able to probe beneath the ocean’s surface to layers not observable from space. At first, when he began recording data with the sensors on profiling floats, there was nothing unusual in the data.
“Then in 2006, a float got stuck in an eddy and suddenly, at 1,000-meter depths, we saw an elevated amount of particles we had not seen during the whole mission,” he says. “The sensor had been stable over three years. There’s nothing at the surface that could explain how these particles were produced. I still have no idea where they came from. That’s what makes this research exciting.”
Scientists are particularly interested in particles sinking to great depths — an important process in carbon sequestration from the atmosphere. Boss is focused on the connection between the ocean physics and the biosphere — the part of the Earth and its atmosphere that is capable of supporting living organisms.
During photosynthesis, plants convert carbon dioxide into organic particles that are distributed throughout the upper water column. Some remain suspended while others are carried to depth.
“It’s crucial we understand their dynamics if we want to understand the role of the ocean in the carbon cycle,” Boss says.