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Who Are NASA's Earth Explorers?

The elementary school student wondering how El Niño will affect tomorrow's weather. The scientist studying connections between ozone and climate change. And the farmer using satellite pictures to keep track of crops. All of these people are Earth Explorers -- they are all curious about the Earth system. This series will introduce you to NASA Earth Explorers, young and old, with many backgrounds and interests.

It doesn't matter whether she is under water or on dry land. The view is the same for oceanographer Heidi Dierssen. In neither place does she see as many female colleagues as she would like.

The number of women who earn degrees in oceanography and other Earth sciences is on the rise. But males still outnumber females by a margin of more than 3-to-2. That's what a 2004 study by the National Science Foundation said. The gap is even larger for those who go on to academic careers. Less than 1 in 4 Earth science faculty are women, the study found.
In sunglasses and a wetsuit, Heidi Dierssen sits near the edge of a boat with the ocean in the background.

Image to right: Heidi Dierssen cruises the shallow ocean waters off the southern tip of Florida.
Credit: Heidi Dierssen

These numbers are troubling to Dierssen. Her concern isn't so much for herself. She's already an accomplished, hardworking scientist. She's a professor at the University of Connecticut. She has degrees in geography and biology.

Instead, she is more worried about her daughters, ages 5 and 3. And she is worried for young girls everywhere. She wonders if society pushes females away from math and science. She wonders how to inspire female scientists of the future.

"It would crush me to see [my girls] lose confidence" in their ability to do anything they set their mind to, Dierssen said. "We as a culture need to do better to encourage girls in math and sciences."

Dierssen is doing her part to show that women can achieve as much in math and science as men. She studies how satellites in space can be used to monitor seagrass. She does this with funding from NASA.

Seagrass is a kind of plant that grows on the floor of shallow coastal waters. Seagrass is important to sea life and coastal cities. It provides food and habitat for many animals in the water. Seagrass helps maintain the quality of water. It also protects the shore from erosion. The problem is, there is less seagrass now than there was years ago. The decrease is due to factors such as pollution, boating and disease.

A square grid and a clipboard with a data table rest on the ocean floor
Image to left: Grids like this one help Heidi measure the amount of seagrass on the ocean floor.
Credit: Laura Bodensteiner

Scientists want to track changes in seagrass all over the world. Satellites are great for watching the surface of the world's oceans. But they have trouble seeing through to the ocean bottom. So how can satellites help keep watch over seagrass? It turns out that the color of the ocean's surface can tell us a lot about what's underneath.

For Dierssen, making the link between ocean color and seagrass means getting wet. She spends a good part of her research time on or in shallow ocean water. While at sea, she measures how light passes through the water and reflects off the ocean bottom. She also takes pictures of the seafloor with a waterproof digital camera. And she collects seawater to examine later.

All of this data goes toward creating mathematical formulas. These formulas compare ocean color to seagrass amounts. Accurate and timely information about seagrass could have several benefits. One would be measuring the health of fishing areas. Another would be tracking projects that restore seagrass.

The water Dierssen dives into is often pretty warm and only about 3 to 5 meters (10 to 15 feet) deep. But there are some risks, such as strong currents and fish that can be way too friendly.

"One time when the water was so [murky] I couldn't see beyond my knees, a remora (also known as a suckerfish) came flying at me from the left and tried to attach itself to my bottom lip," she said. "'Ouch!' I think I screamed underwater. It apparently mistook me for a shark."

A diver hovers over a bed of seagrass as she scuba dives near the ocean floor
Image to right: While studying seagrass on the ocean floor, divers have to keep an eye out for fish and strong currents. Credit: Laura Bodensteiner

Sometimes the threats come from the sky above. Dierssen's most recent outing in the waters off the Florida Keys was cut short. She had to stop one week early because of an approaching hurricane.

Even with sucking fish and hurricanes, Dierssen says she loves her field trips to the water. The only part she doesn’t like is being away from her family. Each trip can last two to three weeks.

She thinks about her daughters when she spends days at sea or hours in the lab. She says she wants to show them that it's possible to have success in your job and also raise a family.

She says she wants her daughters and other girls "to achieve all they can in life, including math and science. I want to ... let them know that they can have a positive impact on the world."

See previous Earth Explorers articles:
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Related Resource
Ocean World
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Dan Stillman, Institute for Global Environmental Strategies