Livingplanet - Blog Posts

From Microscopic to Multicellular: Six Stories of Life that We See from Space

Life. It's the one thing that, so far, makes Earth unique among the thousands of other planets we've discovered. Since the fall of 1997, NASA satellites have continuously and globally observed all plant life at the surface of the land and ocean. During the week of Nov. 13-17, we are sharing stories and videos about how this view of life from space is furthering knowledge of our home planet and the search for life on other worlds.

Earth is the only planet with life, as far as we know. From bacteria in the crevices of the deepest oceans to monkeys swinging between trees, Earth hosts life in all different sizes, shapes and colors. Scientists often study Earth from the ground, but some also look to our satellites to understand how life waxes and wanes on our planet.

Over the years, scientists have used this aerial view to study changes in animal habitats, track disease outbreaks, monitor forests and even help discover a new species. While this list is far from comprehensive, these visual stories of bacteria, plants, land animals, sea creatures and birds show what a view from space can reveal.

1. Monitoring the single-celled powerhouses of the sea

Known as the grass of the ocean, phytoplankton are one of the most abundant types of life in the ocean. Usually single-celled, these plant-like organisms are the base of the marine food chain. They are also responsible for the only long-term transfer of carbon dioxide from Earth’s atmosphere to the ocean. 

Even small changes in phytoplankton populations can affect carbon dioxide concentrations in the atmosphere, which could ultimately affect Earth’s global surface temperatures. Scientists have been observing global phytoplankton populations continuously since 1997 starting with the Sea-Viewing Wide Field-of View Sensor (SeaWiFS). They continue to study the small life-forms by satellite, ships and aircrafts.

2. Predicting cholera bacteria outbreaks

Found on the surface of zooplankton and in contaminated water, the bacteria that cause the infectious disease cholera — Vibrio cholerae — affect millions of people every year with severe diarrhea, sometimes leading to death. While our satellite sensors can’t detect the actual bacteria, scientists use various satellite data to look for the environmental conditions that the bacteria thrive in. 

Specifically, microbiologist Rita Colwell at the University of Maryland, College Park, and West Virginia University hydrologist Antar Jutla studied data showing air and ocean temperature, salinity, precipitation, and chlorophyllconcentrations, the latter a marker for zooplankton. Anticipating where the bacteria will bloom helps researchers to mitigate outbreaks.

Recently, Colwell and Jutla have been able to estimate cholera risk after major events, such as severe storms, by looking at satellite precipitation data, air temperature, and population maps. The two maps above show the team's predicted cholera risk in Haiti two weeks after Hurricane Matthew hit over October 1-2, 2016 and the actual reported cholera cases in October 2016.

3. Viewing life on land

From helping preserve forests for chimpanzees to predicting deer population patterns, scientists use our satellites to study wildlife across the world. Satellites can also see the impacts of perhaps the most relatable animal to us: humans. Every day, we impact our planet in many ways including driving cars, constructing buildings and farming – all of which we can see with satellites.

Our Black Marble image provides a unique view of human activity. Looking at trends in our lights at night, scientists can study how cities develop over time, how lighting and activity changes during certain seasons and holidays, and even aid emergency responders during power outages caused by natural disasters.

4. Tracking bird populations

Scientists use our satellite data to study birds in a variety of ways, from understanding their migratory patterns, to spotting potential nests, to tracking populations. In a rather creative application, scientists used satellite imagery to track Antarctica’s emperor penguin populations by looking for their guano – or excrement.

Counting emperor penguins from the ground perspective is challenging because they breed in some of the most remote and cold places in the world, and in colonies too large to easily count manually. With their black and white coats, emperor penguins are also difficult to count from an aerial view as they sometimes blend in with shadows on the ice. Instead, Phil Trathan and his colleagues at the British Antarctic Survey looked through Landsat imagery for brown stains on the sea ice. By looking for penguin droppings, Trathan said his team identified 54 emperor penguin colonies along the Antarctic coast.

5. Parsing out plant life

Just as we see plants grow and wilt on the ground, satellites observe the changes from space. Flourishing vegetation can indicate a lively ecosystem while changes in greenery can sometimes reveal natural disasters, droughts or even agricultural practices. While satellites can observe plant life in our backyards, scientists can also use them to provide a global picture. 

Using data from satellites including SeaWiFS, and instruments including the NASA/NOAA Visible Infrared Imaging Radiometer Suite and the Moderate Resolution Imaging Spectroradiometer, scientists have the most complete view of global biology to date, covering all of the plant life on land and at the surface of the ocean.

6. Studying life under the sea

Our satellites have helped scientists study creatures living in the oceans whether it’s finding suitable waters for oysters or protecting the endangered blue whale. Scientists also use the data to learn more about one of the most vulnerable ecosystems on the planet – coral reefs.

They may look like rocks or plants on the seafloor, but corals are very much living animals. Receiving sustenance from photosynthetic plankton living within their calcium carbonate structures, coral reefs provide food and shelter for many kinds of marine life, protect shorelines from storms and waves, serve as a source for potential medicines, and operate as some of the most diverse ecosystems on the planet.

However, coral reefs are vulnerable to the warming of the ocean and human activity. Our satellites measure the surface temperature of ocean waters. These measurements have revealed rising water temperatures surrounding coral reef systems around the world, which causes a phenomenon known as “coral bleaching.” To add to the satellite data, scientists use measurements gathered by scuba divers as well as instruments flown on planes.

During the week of Nov. 13-17, check out our stories and videos about how this view of life from space is furthering knowledge of our home planet and the search for life on other worlds. Follow at www.nasa.gov/Earth.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Solar System: 10 Things to Know This Week

The Living Planet Edition

Whether it's crops, forests or phytoplankton blooms in the ocean, our scientists are tracking life on Earth. Just as satellites help researchers study the atmosphere, rainfall and other physical characteristics of the planet, the ever-improving view from above allows them to study Earth's interconnected life.

1. Life on Earth, From Space

While we (NASA) began monitoring life on land in the 1970s with the Landsat satellites, this fall marks 20 years since we've continuously observed all the plant life at the surface of both the land and ocean. The above animation captures the entirety of two decades of observations.

2. Watching the World Breathe

With the right tools, we can see Earth breathe. With early weather satellite data in the 1970s and '80s, NASA Goddard scientist Compton Tucker was able to see plants' greening and die-back from space. He developed a way of comparing satellite data in two wavelengths.

When healthy plants are stocked with chlorophyll and ready to photosynthesize to make food (and absorb carbon dioxide), leaves absorb red light but reflect infrared light back into space. By comparing the ratio of red to infrared light, Tucker and his colleagues could quantify vegetation covering the land.

Expanding the study to the rest of the globe, the scientists could track rainy and dry seasons in Africa, see the springtime blooms in North America, and wildfires scorching forests worldwide.

3. Like Breathing? Thank Earth's Ocean

But land is only part of the story. The ocean is home to 95 percent of Earth's living space, covering 70 percent of the planet and stretching miles deep. At the base of the ocean's food web is phytoplankton - tiny plants that also undergo photosynthesis to turn nutrients and carbon dioxide into sugar and oxygen. Phytoplankton not only feed the rest of ocean life, they absorb carbon dioxide - and produce about half the oxygen we breathe.

In the Arctic Ocean, an explosion of phytoplankton indicates change. As seasonal sea ice melts, warming waters and more sunlight will trigger a sudden, massive phytoplankton bloom that feeds birds, sea lions and newly-hatched fish. But with warming atmospheric temperatures, that bloom is now happening several weeks earlier - before the animals are in place to take advantage of it.

4. Keeping an Eye on Crops

The "greenness" measurement that scientists use to measure forests and grasslands can also be used to monitor the health of agricultural fields. By the 1980s, food security analysts were approaching NASA to see how satellite images could help with the Famine Early Warning System to identify regions at risk - a partnership that continues today.

With rainfall estimates, vegetation measurements, as well as the recent addition of soil moisture information, our scientists can help organizations like USAID direct emergency help.

The view from space can also help improve agricultural practices. A winery in California, for example, uses individual pixels of Landsat data to determine when to irrigate and how much water to use.

5. Coming Soon to the International Space Station

A laser-based instrument being developed for the International Space Station will provide a unique 3-D view of Earth's forests. The instrument, called GEDI, will be the first to systematically probe the depths of the forests from space.

Another ISS instrument in development, ECOSTRESS, will study how effectively plants use water. That knowledge provided on a global scale from space will tell us "which plants are going to live or die in a future world of greater droughts," said Josh Fisher, a research scientist at NASA's Jet Propulsion Laboratory and science lead for ECOSTRESS.

6. Seeing Life, From the Microscopic to Multicellular

Scientists have used our vantage from space to study changes in animal habitats, track disease outbreaks, monitor forests and even help discover a new species. Bacteria, plants, land animals, sea creatures and birds reveal a changing world.

Our Black Marble image provides a unique view of human activity. Looking at trends in our lights at night, scientists can study how cities develop over time, how lighting and activity changes during certain seasons and holidays, and even aid emergency responders during power outages caused by natural disasters.

7. Earth as Analog and Proving Ground

Just as our Mars rovers were tested in Earth's deserts, the search for life on ocean moons in our solar system is being refined by experiments here. JPL research scientist Morgan Cable looks for life on the moons of Jupiter and Saturn. She cites satellite observations of Arctic and Antarctic ice fields that are informing the planning for a future mission to Europa, an icy moon of Jupiter.

The Earth observations help researchers find ways to date the origin of jumbled, chaotic ice. "When we visit Europa, we want to go to very young places, where material from that ocean is being expressed on the surface," she explained. "Anywhere like that, the chances of finding biomarkers goes up - if they're there."

8. Only One Living Planet

Today, we know of only one living planet: our own. The knowledge and tools NASA developed to study life here are among our greatest assets as we begin the search for life beyond Earth.

There are two main questions: With so many places to look, how can we home in on the places most likely to harbor life? What are the unmistakable signs of life - even if it comes in a form we don't fully understand? In this early phase of the search, "We have to go with the only kind of life we know," said Tony del Genio, co-lead of a new NASA interdisciplinary initiative to search for life on other worlds.

So, the focus is on liquid water. Even bacteria around deep-sea vents that don't need sunlight to live need water. That one necessity rules out many planets that are too close or too far from their stars for water to exist, or too far from us to tell. Our Galileo and Cassini missions revealed that some moons of Jupiter and Saturn are not the dead rocks astronomers had assumed, but appear to have some conditions needed for life beneath icy surfaces.

9. Looking for Life Beyond Our Solar System

In the exoplanet (planets outside our solar system that orbit another star) world, it's possible to calculate the range of distances for any star where orbiting planets could have liquid water. This is called the star's habitable zone. Astronomers have already located some habitable-zone planets, and research scientist Andrew Rushby of NASA Ames Research Center is researching ways to refine the search. "An alien would spot three planets in our solar system in the habitable zone [Earth, Mars and Venus]," Rushby said, "but we know that 67 percent of those planets are not inhabited."

He recently developed a model of Earth's carbon cycle and combined it with other tools to study which planets in habitable zones would be the best targets to look for life, considering probable tectonic activity and water cycles. He found that larger planets are more likely than smaller ones to have surface temperatures conducive to liquid water. Other exoplanet researchers are looking for rocky worlds, and biosignatures, the chemical signs of life.

10. You Can Learn a Lot from a Dot

When humans start collecting direct images of exoplanets, even the closest ones will appear as only a handful of pixels in the detector - something like the famous "blue dot" image of Earth from Saturn. What can we learn about life on these planets from a single dot?

Stephen Kane of the University of California, Riverside, has come up with a way to answer that question by using our EPIC camera on NOAA's DSCOVR satellite. "I'm taking these glorious pictures and collapsing them down to a single pixel or handful of pixels," Kane explained. He runs the light through a noise filter that attempts to simulate the interference expected from an exoplanet mission. By observing how the brightness of Earth changes when mostly land is in view compared with mostly water, Kane reverse-engineers Earth's rotation rate - something that has yet to be measured directly for exoplanets.

The most universal, most profound question about any unknown world is whether it harbors life. The quest to find life beyond Earth is just beginning, but it will be informed by the study of our own living planet.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.