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A Holistic Perspective on Florida’s Wetland Emissions 

by Cheryl Doughty, Qing Ying, and Erin Delaria (University of Maryland/NASA’s Goddard Space Flight Center and Ayia Lindquist (SSAI/NASA’s Goddard Space Flight Center

Like other early career researchers who collaborate to address Earth’s most pressing issues, we four scientists work together to support NASA’s BlueFlux project, bringing together data that allow us to observe important changes happening on our Earth. We are driven by the question “Will the benefits we get from wetlands be lost with the ever-increasing pressures of human needs and climate change?”

To address these issues, our science takes us from NASA’s Goddard Space Flight Center (GSFC) to the field. We’ll splash into mangrove and freshwater wetlands of the Everglades with Cheryl Doughty of the University of Maryland and GSFC’s Qing Ying; we’ll take off in planes to fly over the South Florida region with Erin Delaria, also from GSFC; and we’ll assimilate into the communities of people whose lives are intertwined with the health of the whole Everglades ecosystem with GSFC’s Ayia Lindquist. Along with the many scientists who helped with the BlueFlux field campaign that began in 2022, our shared research goal is to better understand whether wetlands will remain resilient carbon sinks as they face changing conditions in an environment heavily influenced by humans.

Two dozen people in summer clothes pose in a formal group on a Washington, D.C., rooftop, with the dome of the U.S. Capitol in the background.
The first cohort of the BlueFlux team of scientists, students, and stakeholders including NASA’s Goddard Space Flight Center’s (GSFC) Qing Ying (first row, 3rd from right), the University of Maryland’s Cheryl Doughty (first row, 5th from right), Erin Delaria (first row, 6th from right), and Ayia Lindquist (back row, 1st from right), both also from GSFC. The team was brought together for a workshop in Washington, D.C. in 2023 by the project’s first principal investigator, Ben Poulter, Senior Scientist of Spark Climate Solutions (back row, 4th from left).
Florida International University (FIU) in DC.

March 16 – 24, 2022: Forest inventory team, field campaign #1

Our first days of the field campaign began in the Ten Thousand Islands National Wildlife Refuge, which marks the northwest corner of the larger Everglades ecosystem that extends from Lake Okeechobee southward to the Everglades National Park and is bordered by large urban coastal cities including West Palm Beach, Fort Lauderdale, and Miami to the east. This refuge is often described as a labyrinth of water and mangroves, making it a suitable home to many creatures of land and sea — and best explored by boat!

In the photo at top left, the gleaming wet profile of a dolphin’s head and back emerge from calm water as it rides the wake of a small boat. At top right, the eye bumps and rough, scaled back of a crocodile is revealed as it floats mostly submerged beside a dock. Bottom, a flock of birds soars beyond towering cumulus clouds, above a dark treeline of mangroves.
Thanks to a boat ride from our collaborators David Lagomasino and Sean Charles of East Carolina University (ECU), our exploration of the mangroves of Ten Thousand Islands National Wildlife Refuge began with sightings of dolphins (top left), crocodiles (top right), and wading birds in flight (bottom).
Cheryl Doughty

Our fieldwork on foot in the wetlands that dominate Florida’s coasts allowed us to experience firsthand a range of contrasting mangrove conditions. These forest plots can be so dense with trees that it’s hard to see the scientists, but luckily the green canopy lets us work in the shade. The soils here are squishy and always slightly wet, covered with falling leaf litter, and quite smelly— but you learn to love how rotten eggs smell when it’s coming from a healthy mangrove forest.

We began by visiting a healthy and regenerating mangrove forest to conduct our fieldwork to inventory the above- and belowground carbon stocks — snapshots of where and how much carbon, the element foundational to all life on Earth, is stored. We do this by measuring the height and diameter of individual trees within a given area and using allometric equations to estimate how much biomass is aboveground. For belowground estimates, we use a special tool called a peat auger that’s a cross between a shovel and a sword. It extracts a cylindrical core of the soil that can tell us how much biomass and carbon is stored beneath the mangroves.

At left, two scientists clad in long-sleeved shirts and cloth sunhats are barely-visible blurs obscured by mangrove sprouts. At right, a woman in the foreground uses a yellow folding ruler to measure the root of a mangrove, while the worker beside her measures another. In the background, a third observer turns her gaze to the leaves at the top of a sprig. All are clad in long sleeves, neck scarves, hats, long pants, and boots. The mangroves surround them in a dense thicket.
At left, Anthony Campbell and Nathan Thomas of NASA Goddard Space Flight Center (GSFC) take measurements to estimate aboveground biomass in a healthy mangrove forest. At right, Abigail Barenblitt of GSFC measures tree diameter while Shalimar Moreno and Sean Charles of ECU sample a freshly collected mangrove peat core.
Cheryl Doughty

The next day we didn’t have to travel far to reach an otherworldly example of what a mangrove forest can become when it gets damaged from hurricanes and is not able to recover. These areas have earned the eerie title of mangrove “ghost forests.” To compare these desert-like areas to the healthy forests, we take similar measurements for aboveground and belowground carbon; however, there are a few extra observations we need in order to assess the amount of carbon stored in standing dead trees and fallen branches and trunks. 

At left, the camera looks down on an observer working with a small knife on a two-foot length of mangrove sapling. Beside him is a plastic bag of labeled samples, other gear, a backpack, and the foot of a passing colleague. The terrain is dry, cracked, pale brown mud. At right, a bearded man in t-shirt, long pants, boots and a cloth sunhat surveys a mangrove ghost forest with binoculars. He is surrounded by dead stalks and cracked, dry mud in a swirl of cocoa brown and pale tan.
At left, David Lagomasino of ECU breaks down a core of dry mangrove mud into samples for lab processing. At right, Anthony Campbell estimates the height of standing deadwood in a mangrove ghost forest, using an instrument called a hypsometer.
Cheryl Doughty

Three days into our campaign, we made the drive into the Everglades National Park. The enormity of this ecosystem was felt in the hours of driving, but even more so in the diversity of many wetland types we passed through along the way. As we drove south, the influence of freshwater draining slowly from Lake Okeechobee graded into the more low-lying coastal influence of saltwater tides. We stopped at the same vistas frequented by the million visitors to the park every year, collecting a few vital measurements along the way.

At top left, a snowy egret – a long-legged, white wading bird— stands at the edge of a pool of water that reflects blue sky and clouds, surrounded by green and gold swamp. At top right, a wooden boardwalk and walkway crosses a broad landscape of swamp and mangroves under a bright, clouded sky. At bottom left, a young woman leans a laptop against the rail of a wooden observation boardwalk, and points out something on the screen to two companions. A handheld instrument (the spectrometer) is attached to the computer; both have been taken out of a large plastic bag brought along to protect them. Beyond them, healthy mangroves form the background. At bottom right, a portion of gray ghost forest shows the effects of saltwater inundation: the dry-mud ground is crusted with white, and the dead stalks of trees and fallen trunks show no signs of life.
Stops along the gradient from freshwater wetlands and cypress forest to saltwater mangrove forests showed different levels of hurricane impacts in the Everglades National Park. At bottom left, Qing Ying (GSFC) demonstrates how a spectrometer takes measurements of a healthy mangrove canopy.
Cheryl Doughty

One important measurement we took was from a special instrument called a spectrometer, which helps us connect what’s on the earth surface to what’s seen by satellites. That’s always the goal when working on NASA-funded research! The spectrometer captures how sunlight bounces off whatever you point it at —plants, soils, water—using a fiber cable that outputs a “spectra” or graph, showing light reflectance at each wavelength of the sunlight spectrum. This spectrum ranges from the visible light that human eyes see and that plants absorb to do photosynthesis— to the near-infrared energy that is important for monitoring plants’ health. When we pair this data with other satellite images or data collected by NASA, it helps us understand the health of wetland ecosystems at a much bigger scale.

a) a healthy stand of mangrove with its characteristic thick, round leaves; (b) a tree with above-ground roots and narrow, thin leaves; (c) dead mangrove saplings and roots; (d) mangrove sprouts behind the broad trunk of another tree; (e)small saplings poke up from the mud below mangrove roots; (f) a graph showing the various wavelengths of spectral reflectance curves of these plants. The sapling mangrove shows the highest reflectance, with the regrowing mangrove and succulents following similar lines in terms of level of reflectance. Lowest are the dwarf mangrove and fallen dry mangrove trunk.
Spectral reflectance curves of (a) mangrove, (b) succulent, (c) dead mangroves, and (d) regrowing young mangroves in a gap of a healthy mangrove forest, (e) mangrove saplings in the gap, and (f) their reflectances measured by the spectrometer.
Photos by —Qing Ying | Graph adapted from Poulter, P. et al. (2023).

For the rest of the field campaign, we repeated our collections of data on plant reflectance and forest inventories in select mangrove areas that represent a wide range of mangrove health and hurricane impacts across the Everglades.

It’s important to understand where and how mangroves are recovering, or regenerating. We see this best as seedings spring up in the mud or as new sprouts emerge from the dead trunks. All the ecological possibilities at these small scales have big implications for how the mangroves’ relationship to carbon is changing.

The balance of carbon uptake and emissions is at risk. As mangroves photosynthesize through their wide, thick, round leaves, they take carbon from the atmosphere and store it, sinking it into their woody biomass and wet soil. The health of mangrove forests impacts the Everglades’ ability to act as a carbon sink; thus a warming ecosystem impacted by humans and climate change could become a carbon source.

A young woman in plastic shoes, long pants, a long-sleeved shirt, and a baseball cap, balances on a plank suspended over shallow, muddy water. She carries a laptop on a strap around her shoulders and waist. It’s connected via a cable to a hand-held black plastic spectrometer. A second observer, clad in full protective garb, including hood and gloves, squats on the plank, holding the instrument toward mangrove sprouts extending 12 inches above the surface of the water. In the background is a healthy mangrove forest.
Qing Ying and Shalimar G. Moreno (ECU) take spectral measurements in a healthy mangrove forest.
Jonathan Gewirtzman

Looked at together, this data will help us understand what’s happening to the carbon in this important ecosystem over longer time scales and over bigger geographic areas. To help with this, we capitalize on NASA’s efforts to develop technology that can be tested over large regions, using planes.

April 19 – 26, 2022 – Airborne flux team, flight deployment #1

High above the ground crews wading through mangrove forests, BlueFlux researchers took to the skies over southern Florida, using airborne measurements of vertical winds and two important greenhouse gases—carbon dioxide and methane—to  measure how much of these gases are being released or absorbed across thousands of kilometers of wetlands. Flying at 300 feet to capture these turbulent signals, it was often a very bumpy ride! But by measuring the balance of carbon dioxide and methane carried within eddies — spirals of water — below, we could piece together the bigger picture of how carbon moves across this incredibly diverse landscape.

From the air, the landscape unfolded as a mosaic of distinct coastal ecosystems, each with its own role in carbon cycling. Dense mangrove forests formed dark green canopies along the coast and tidal channels, while lighter-toned marshes and sawgrass prairies stretched inland in patchwork patterns shaped by water flow. Open water, mudflats, and transitional zones added further texture, highlighting just how heterogeneous these environments are at the scales we sampled. Flying over this diversity made it clear that carbon fluxes aren’t uniform—even over short distances, differences in vegetation type, inundation, and productivity can drive major shifts in how these ecosystems exchange carbon with the atmosphere.

From the mangrove forests to the flooded marshes, we saw how vegetation type, ecosystem health, and changing water levels all shape whether these ecosystems act as carbon sinks or sources. More than 100 flight hours, spanning multiple seasons, provided a dynamic picture of how the ecosystems breathe, revealing that carbon uptake and emissions vary dramatically, depending on vegetation type, water levels, and time of year. Mangroves, in particular, stood out as strong carbon sinks, demonstrating the highest carbon dioxide uptake rates that we observed across all our observation flights.

A white twin- engine propeller plane stands on a runway under sunny skies.
Here’s the Dynamic Aviation A90 aircraft used for the first four BlueFluxflight deployments at Homestead Executive Jet Center in Homestead, Florida.
Erin Delaria

At top left, the white wing of a plane extends over a prairie of thin, uniform, pale green sawgrass edged by a distant swatch of blue water. At top right, broad salt marsh makes a mottled scape of muddy water reflecting the sky and the pale green of mangroves. Bottom, the plane’s wing hovers over a forest of uniform, tight-knit trees, under the sun and shadow of partial clouds.
Aerial views reveal the striking contrasts across the landscape: dense mangrove canopies (top left), a sawgrass mosaic in a flooded freshwater marsh (top right), and tightly clustered cypress hammocks (bottom).
Erin Delaria

Alongside the differences in carbon exchange across vegetation types, our measurements also let us see the stark imprint of past hurricanes — especially in patches of mangrove ghost forests, where 2017’s Hurricane Irma caused extensive dieback. Over these areas, we frequently observed elevated carbon dioxide and pronounced methane emissions, clear signals that hurricane damage shifted the landscape from a major carbon sink to a net carbon source.

The plane’s wing is shown flying over land that is primarily a dead gray, with occasional spots of green vegetation. The sea on the horizon reflects a sky of stormy clouds, with the water shading from pale green at the coast to deep blue-gray where sea meets sky.
From the skies, mangrove ghost forests appear like scars on the formerly lush landscape.
Erin Delaria

October 12 – 20, 2022 – Airborne flux team, flight deployment #2

Healthy mangrove forests, viewed from above, are emerald swaths enmeshed with water that reflects the sky.
Healthy mangrove forests, viewed from above, are emerald swaths enmeshed with water that reflects the sky. Plane pilot L. Grippo took this photo from the cockpit.
L. Grippo

When we returned to our study area in October, the landscape had been transformed after a summer of heavy rains. Wetlands that had been only partially inundated were now broadly flooded, and the shift in hydrology was reflected in our measurements of carbon fluxes. Methane emissions were noticeably higher, especially over cypress swamp forests and freshwater marshes, where standing water creates ideal conditions for methane production. At the same time, the highly productive bald cypress hammocks, looking like elevated islands of dense trees rising above the surrounding marshes, had begun to brown and shed their needles for the season, sharply reducing their capacity to store carbon dioxide. These changes gave us our first clear picture of how strongly carbon exchange here shifts between wet and dry seasons — again, driven by rainfall, water levels, and the seasonal rhythms of the ecosystem.

Our flight crews also got their first taste of groundwork in October. We joined field teams for a day of tromping through mud to measure carbon dioxide and methane fluxes from within a mangrove forest site. It didn’t take long to gain a new appreciation for the effort behind those measurements—long hours, thick mud, and dense clouds of mosquitos. By the end of the day, there was a shared respect for the ground team’s work, along with an acknowledgement that flying might just be the more comfortable side of the operation — provided that you don’t get airsick!

The scientist’s photographs of her own shoes show the “before” image, clean and dry as she reclines in a hammock attached to a chain link fence, with an airport runway beyond it, and “after,” so brown, wet, and muddy that they almost completely blend into the muddy swamp where she’s at work.
Erin Delaria lounged outside the airfield (top) and, later, displayed her muddy shoes during a day of ground work (bottom). 
Erin Delaria

October 22 – 27, 2022 – Chamber flux field team, field campaign #2

Returning to the Everglades National Park in October during the wet season proved to be just that — wet! This trip was to help the team from Yale School of the Environment (YSE), which would work to measure how carbon dioxide and methane fluxed over the day by attaching air-tight chambers directly to trees. Their work assesses the extent to which each gas is either stored or emitted by various types and parts of healthy and dead mangroves. While our feet got wet at our first stop in a recovering mangrove ghost forest, the team made sure the gas analyzer equipment stayed safe and dry while connected by tubes to each measurement chamber. 

At the top, two men wade shin-deep through a swamp’s gray water. In the foreground, a man in sunhat, sunglasses, a t-shirt and long, sodden pants, carries a yellow gas analyzer on his back. His companion stands behind him, his face obscured by his hat as he makes notes on a portable device with a hot pink cover. At the bottom, amid muddy, ankle-deep water, a group of six researchers examines the trunks of dead trees in a ghost forest. In the foreground, a blue inflatable dinghy carries backpacks, a clear plastic box, and other equipment.
At the top, the chamber flux team used portable gas analyzers to sample gases emitted or absorbed by live and dead trees in a flooded mangrove recovery site. Jonathan Gewirtzman of Yale School of the Environment (YSE) leads the way, followed by Michael Norton. Bottom, shown here are Jonathan Gewirtzman, Michael Norton, Samuel Tsao, Michael Norton, Nadav Bendavid, and Jessica Peterman, of YSE. The gas analyzer equipment was safely transported by inflatable boat and on the backs of scientists.
Cheryl Doughty

The next day, the team ventured into a healthy and much denser mangrove forest with the gas analyzers on our backs. If you’ve ever had the pleasure of making your way through a 3-D maze of interwoven mangrove knees and roots surrounded by water and sloppy mud, you may understand just how amazed I am that we made it in (and out) without any snags on the inflatables or any slips into the muddy water we were slogging through with expensive equipment on our backs. Once at the sampling site, it was another full day of measuring gases going in and out of trees. These novel measurements are what we need in order to understand just how variable carbon uptake and emissions can be from second to second, from tree root to trunk, and from resilient to damaged mangrove forests.

At left, a man carrying a yellow gas analyzer backpack hikes a rugged path through closely-planted mangroves. At center, we see the back of a man with a gas analyzer on his back. He wears long pants and long sleeves and a cloth hat for protection from sun and bugs. The ground under his feet is dry and dark reddish brown. Barely visible in tangle of branches, leaves, and roots are two other researchers. At right, two women peer through the leaves of mangrove trees.
Into a dense mangrove forest Michael Norton goes (left), carrying gas analyzers to measure how carbon gases flux. Jonathan Gewirtzman (center) sets off to analyze mangrove trees. Jessica Peterman and Nadav Bendavid (right) are barely visible in the thicket.
Cheryl Doughty

July 13 – 19, 2024 – Airborne flux team, flight deployment #5

The flight team returned for one final set of measurements in July 2024, in the heart of the wet season, capturing a last snapshot of how carbon exchange shifts across seasons. During this time of year, South Florida sees near-daily thunderstorms that continually soak the landscape with fresh water. This final deployment also brought together flight scientists Piper Read and Erin Delaria with Dynamic Aviation pilots KT Kinne and Lilia Farr—forming a rare all-female NASA mission.

A team of four woman pose in front of a gray twin-engine plane standing beside a hangar.. The runway below is wet and shining; the sky above is gray cloud, with a patch of blue visible on the horizon.
From left to right: Piper Read, Erin Delaria, and KT Kinne and Lilia Farr of Dynamic Aviation front of the A200 aircraft used for the final set of BlueFlux survey flights.
G. Wolfe

April 2023 – Community engagement team, outreach events

April is often synonymous with Earth Month in the outreach community, due to the volume of events focused on engaging the public on environmental causes. South Florida is no different, putting its own flair on Earth Month events, to which the BlueFlux team had the opportunity to contribute! One of the key aspects of BlueFlux and other Carbon Monitoring System-funded projects, is strong stakeholder partnerships. We were invited by the Seminole Tribe of Florida, one of our key community partners, to share about our BlueFlux project and introduce their community to NASA Earth Science at their Earth Day event. There, the team had the opportunity to speak with Seminole Tribal and local community members about the science we are doing, answer questions, and strengthen local relationships. 

At left, a man in shorts, t-shirt, and cap peers through the plane’s hatch to see its interior. Center, a group of visitors stands in front of a kiosk bearing the NASA insignia, in conversation with members of the research team. The table between them holds posters and fliers about the research program. At right, Smokey the Bear stands between two women, one in a pink flowered dress, the other in shorts and a tee. A table with a NASA insignia is visible to the rear.
The team engages with the public through various community outreach events hosted in Florida. At left, a visitor gets a peek inside the plane at the BlueFlux Open House. Center, questions were answered and information was supplied at this public event, held in Marathon, Florida. At right, Frannie Adams (YSE) and Ayia Lindquist gain another supporter of BlueFlux science at Seminole Earth Day in Hollywood, Florida.
Ayia Lindquist

Later that same week, the team had planned an open house with the local Museum of Diving in Marathon, Florida. Our community partners Florida International University’s Florida Coastal Everglades Long Term Ecological Research (FCE-LTER) program and the conservation group Coastlove joined us to host a special Earth Day event in the Keys. In addition to opening the aircraft and instruments to the public, we also held a mangrove planting and clean-up to connect the science we are doing to on-the-ground restoration efforts. Attendees planted over 30 young mangroves and collected over 200 pounds of trash, enjoying a holistic Earth Day experience. From doing direct community outreach and engagement and working closely with local decision makers,  the BlueFlux team has been deeply involved in ensuring our research is impactful locally. The team continues to engage in how to integrate the research into helpful decision making.

Because our BlueFlux science is funded by NASA, we owe it to the public to make our data available and accessible. We feel it is important to communicate our science at many levels to anyone who wants to learn more. If you’d like to read more about how the airborne fluxes change with the season over such an incredibly heterogeneous mosaic of wetland types, you can read our publication in the Journal of Geophysical Research: Biogeosciences. Or you can check out our publicly available dataset of airborne fluxes. You can also find out more about how the field and airborne data we collected were combined for a regional perspective of wetland greenhouse gas emissions over the entire Everglades for the last 23 years in our recently published PNAS study. For more hands-on exploration of the results of our study, please see our  interactive web app on Google Earth Engine.