Groton — A marine sciences and geography professor at the University of Connecticut at Avery Point is leading a team of about 100 researchers across the country — and in other countries — working on a satellite mission that the National Aeronautics and Space Administration says "will take Earth's pulse in new ways for decades to come."

Heidi Dierssen leads the Science and Applications Team for NASA's PACE mission (Plankton, Aerosol, Cloud, ocean Ecosystem). A NASA spokesperson said Monday that launch is scheduled for January 2024, with a budget of $964 million.

"Not everyone knows that NASA actually does a lot of oceanography. They think, 'Oh, NASA, let's go look at other planets,'" Dierssen said last week in a talk as part of UConn's Coastal Perspectives Lecture Series. But NASA has been funding her research for decades.

Dierssen said sensors in the past have been targeted to see different parts of the ocean, but this is the first satellite that will look at all oceans. NASA said the two science goals of PACE are to extend ocean color, aerosol, and cloud data records, and to address new questions using advanced instruments.

"It's going to be a really exciting mission, and people throughout the world, really, are excited to use the data," which we'll get in real time once the satellite launches, Dierssen said. Her team has been reaching out to people who will use this data, such as those who do coastal management or work in fisheries.

NASA said the technology of this mission will reveal the diversity of phytoplankton in oceans and show the impact it has on ocean life, which is important because "blooms of carbon-rich phytoplankton fuel the fisheries of New England" but phytoplankton can also be toxic. PACE will also help with forecasting harmful algal blooms, and with assessing oil spills.

Dierssen said PACE "will reveal the lungs of the planet. She explained that we don't know yet whether the net primary productivity — meaning the amount of photosynthesis — of the ocean equals or exceeds that of land.

But she hopes that by better understanding phytoplankton composition and other things required to monitor productivity, the PACE mission will help scientists "do a better job of estimating how the ocean breathes essentially, how it takes in carbon dioxide and breathes out oxygen throughout the planet, and how that changes over time."

Dierssen noted that 97% of the distribution of light from the ocean comes from the atmosphere and from glint off surface reflections, with a small percentage coming from the actual photons that enter the ocean. Because so few photons leave the ocean, it's hard to measure the color of the ocean. Dierssen said PACE will help scientists better get at "this needle in a haystack."

Dierssen said her team includes researchers not only in the U.S., but also in the Netherlands, France and Belgium. The team meets virtually once a month — to discuss advances people are making and gaps in coverage — and annually in person; the last meeting was at Avery Point.

The team is looking at whether it's possible to analyze microplastics in different ways, looking at sea grasses and coral reefs, and working on issues related to dust. Dierssen noted that 50% of the dust over North America comes from other continents.

The Science and Engineering Team is working with the engineering team, advising from a science perspective. Dierssen has been working on PACE for several years.

Dierssen, 54, did her undergraduate and master's degrees in biology at Stanford University and her Ph.D. in geography at the University of California at Santa Barbara, where she was introduced to satellite oceanography. She went to the Antarctic multiple times in graduate school, studying how to model light and biology from satellites, and then moved into researching sea grasses and coral.

At Avery Point, she teaches Introduction to Geography and Remote Sensing of Marine Geography, and has taught many other classes to marine sciences majors.

Dierssen leads UConn's Coastal Ocean Laboratory for Optics and Remote Sensing, or COLORS, based at Avery Point. In 2018, she was awarded a Fulbright Fellowship to work on hyperspectral remote sensing in Belgium.

NASA's Project Scientist for the PACE mission, Jeremy Werdell, also is a UConn graduate.

e.moser@theday.com