Marissa Cuevas Flores created the company microTERRA.

Q: Let’s talk about environmental scientists. Why did you choose to become one?

A: There are two kinds of environmental scientists. Both kinds study the environment to learn how it behaves. They also learn how people affect it. The first kind study and observe. The second kind try to fix the damage people do. I am the second kind. I try to fix the problems I see.

Q: What environmental problem did you want to solve?

A: Water pollution. Most of our freshwater is used for farming. But many farms use chemicals to cut down on weeds and pests. Water runoff from these farms can cause pollution. This wastewater can cause dead zones.

Each year, millions of tons of chemicals are used worldwide on our crops. Some of it gets washed into our waterways.

Q: What is a dead zone?

A: A dead zone is an area in a river, lake, or ocean that has low oxygen levels. Living things need oxygen. So, few things can live in these places. One thing that can are microalgae. They give off oxygen. They take in chemicals from wastewater.

algae as seen under a microscope

algae in the water

Q: How will you tackle this?

A: I found a way to upcycle wastewater and make it reusable. Microalgae can be used to clean polluted water in fish farms.

Fish farms are a source of water pollution.

Dead zones

Location and Size 

(in square kilometers)

size unknown
1 km2

10 km2 

100 km2 

1,000 km2

10,000 km2 

There are more than 500 dead zones worldwide.