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Who Are NASA's Earth Explorers?

The elementary school student questioning if El Niño occurs anywhere besides the Pacific Ocean. The researcher investigating connections between Arctic ozone depletion and global climate change. The citizen scientist interested in how changing land cover and use affects animal migration patterns. And the businessperson projecting future needs for harvest, delivery and storage of crops. All of these people are Earth Explorers -- they are all connected by their curiosity about Earth system processes. This series will introduce you to NASA Earth Explorers, young and old, with a variety of backgrounds and interests.

In sunglasses and a wetsuit, Heidi Dierssen sits near the edge of a boat with the ocean in the background.
Whether under water or on dry land, when oceanographer Heidi Dierssen looks around she doesn't see as many female colleagues as she would like.

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

Despite a steady increase in the number of women receiving degrees in oceanography and other geosciences, males still outnumber females by a margin of more than 3-to-2, according to a 2004 study by the National Science Foundation. The gap is even larger for those who go on to academic careers - less than 1 in 4 geoscience faculty are women, the study found.

These numbers are troubling to Dierssen, a University of Connecticut assistant professor with degrees in geography and biology. Her concern isn't so much for herself, already an accomplished, hardworking scientist, but more so for two other women - her daughters, ages 5 and 3 - and young girls everywhere.

Does society somehow deter females from pursuing careers in math and science, she wonders, and what should be done to motivate female scientists of the future?

"It would crush me to see [my girls] lose confidence and conform to some predefined standard of femininity," said Dierssen, who recently penned an autobiographical sketch for Oceanography magazine meant to inspire female scientists, young and old. "We as a culture need to do better to encourage girls in the math and sciences."

Dierssen is as good a role model as any for young girls considering a career in math or science. With funding from NASA, she studies how satellites in space can be used for large-scale monitoring of seagrass - flowering plants growing on the seafloor - in shallow coastal waters. Seagrass has decreased over the years as a result of coastal development, stormwater runoff from the land, boating and other water recreation, invasive species and disease.

A square grid and a clipboard with a data table rest on the ocean floor
Scientists are interested in seagrass because of its importance to marine life, coastal communities and the carbon cycle. Seagrass supports ecosystems by providing food and habitat for many aquatic animals, improves water quality by trapping sediment and nutrients, and protects shorelines from erosion by slowing down waves. It may also enhance the ocean's ability to store carbon dioxide.

Image to right: Grids like this one help Heidi measure seagrass abundance. Credit: Laura Bodensteiner

Satellites allow for constant monitoring of the ocean's surface, but they have trouble seeing through to the ocean bottom. With the right information, however, satellite observations of ocean color can be related to concentrations of underwater plants. In the past, scientists have focused on satellite identification of phytoplankton - tiny, free-floating aquatic plants - in the open ocean rather than shallow-water seagrass.

To obtain the data necessary for satellites to recognize and estimate quantities of seagrass from high above the water, Dierssen spends a good part of her research time on or in the water. While at sea, she uses a spectrometer and other sensors to measure the amount of light passing through the water column and reflecting off the ocean bottom, takes pictures of the seafloor with a waterproof digital camera and collects seawater and sediment for later examination.

All of the information gathered goes toward developing mathematic formulas that may enable scientists to infer sea-bottom landscape from satellite images of ocean color. Accurate and timely satellite observations of seagrass could provide several environmental, scientific and economic benefits, including the ability to monitor the health of fisheries, track the status of seagrass restoration projects and incorporate seagrass data into regional and global carbon models.

A diver hovers over a bed of seagrass as she scuba dives near the ocean floor
While the water Dierssen dives into is typically warm and only about 3 to 5 meters (10 to 15 feet) deep, it is not without its risks, which include strong currents and fish that can be way too friendly.

Image to left: While studying seagrass on the ocean floor, divers must keep an eye out for fish and strong currents. Credit: Laura Bodensteiner

"One time when the water was so turbid 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," Dierssen said. "'Ouch!' I think I screamed underwater. It apparently mistook me for a shark."

And sometimes the threats come from the sky above - her most recent outing in the waters off the Florida Keys was cut short by one week due to an approaching hurricane.

Suckerfish and hurricanes aside, Dierssen says she loves most everything about participating in the field campaigns, which usually last two to three weeks, except for having to be away from her family. It is in fact her daughters who she has in mind when she spends days at sea or hours in the lab. Dierssen says she wants to show them and other girls that it is possible to both have a rewarding career and raise a family, even if society suggests otherwise.

"I struggle with the way girls are portrayed by the popular media and want to empower my children to achieve all they can in life, including math and science," Dierssen said. "I want to expose them to other cultures, a diversity of opinions and lifestyles and let them know that they can have a positive impact on the world."

See previous Earth Explorers articles:
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Related Resources
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SeaWiFs: Teachers Resources
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Oceanography Magazine: Women in Oceanography
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Dan Stillman, Institute for Global Environmental Strategies