you're reading...

Remote Sensing

SURFO Special: From outer space to the microscope: How NASA’s satellites are helping us understand the ocean’s smallest life

Each summer, the University of Rhode Island Graduate School of Oceanography (GSO) hosts undergraduate students from all over the country to participate in oceanographic research. These Summer Undergraduate Research Fellows (SURFOs) have not only been working with GSO scientists, but they also have spent part of their time learning how to communicate this science to the public. Although their research experience was virtual this summer, they still did a fantastic job. Read on to find out what they have been up to, and why they everyone should be as excited as they are about their work.


Julia Lober is a rising senior at Tufts University in Medford, MA with a major in Environmental Geology and a minor in Computer Science. Her advisor this summer was Dr. Colleen Mouw.

— — — — — — —

Close your eyes and imagine the ocean. What do you see? Maybe you picture crystal clear water and a sandy beach. Or murky, green water and a rocky shore. Or of a blue open ocean. No matter what you see, you’d be right. The ocean takes on many faces, depending on weather, waves, nutrients, temperature, and other factors.

Orbiting many miles above us, NOAA’s Visible Infrared Imaging Radiometer Suite (VIIRS) satellite sees, and records, all of this. The satellite has an instrument called a radiometer that measures the light emerging from the surface of the ocean – the “color” of the ocean. Scientists in the field of ocean color optics are working to figure out what this satellite information can tell us about the ocean itself.

This map shows average reflectance at 443 nm for July 2019, from the MODIS-Aqua sensor. Warmer colors indicate higher reflectance and cool colors show less reflectance (oceancolor.nasa.gov).

We tend to think of color as a single value; an object can be red or blue, not both. Actually, the color we see is an average of the object’s interaction with light throughout the visible spectrum (about 400 – 700 nm). Our brains translate this into a single color, but the satellite’s sensor allows them to be detected separately.

Right now, the VIIRS satellite takes measurements from 5 wavebands in the visible region of the electro-magnetic spectrum. The new Plankton, Aerosol, Cloud, and ocean Ecosystem (PACE) satellite, planned for launch in 2022, will bring us information from many more wavelengths. A lot of information about the ocean is hidden in the details – the small bumps and wiggles across the spectrum. With this additional detail, scientists are hoping to discover more about one of the ocean’s most important (and tiniest) inhabitants: phytoplankton.

At the base of the food chain, changes in phytoplankton populations affect all other marine life. Monitoring phytoplankton populations is key to managing fisheries and helping us understand the effects of large-scale changes like ocean acidification and ocean warming.

So how do we get from outer space to some of the smallest life in the ocean? When rays of sunlight reach the ocean, three things can happen: they can pass through undisturbed, they can be absorbed, or they can bounce off in a process known as scattering.

Much like your own signature, each sample of water has its own unique optical signature based on its interaction with different wavelengths of light. This signature can be separated based on the constituents in the water (Julia Lober, 2020).

The fate of the light depends largely on what it encounters in the ocean. Pure water absorbs longer wavelengths (reds, oranges, and yellows) and scatters shorter wavelengths (purples and blues). That is, red light disappears and we see only the reflected blues. But the ocean has more than just water; there is also detritus, dissolved substances, and, of course, phytoplankton. Each of these components interacts with light differently and complicates the overall “optical signature” of the water.

We can study phytoplankton composition by focusing on just phytoplankton absorption. Different plankton species have unique optical signatures driven by their shape, pigments, or taxonomy. By comparing characteristics of the overall phytoplankton optical signature and of the group-specific optical signatures, we can learn about what groups are present in the water.

What does this have to do with space? Satellites in orbit can give us the overall optical signature of the water. If we can separate out the individual components, we can get the optical signature of the phytoplankton. From there, we can identify the phytoplankton groups in the ocean. Pretty cool!

The variety of size and shapes of phytoplankton that might be in a single sample of water (ifcb-data.whoi.edu/timeline?dataset=NESLTER_broadscale).

In practice, each of these steps requires a lot of knowledge and assumptions. This summer, I worked with the Mouw Lab, virtually,  to improve our knowledge of these optical relationships specific to the continental shelf waters of the eastern US. Using data from a research cruise that looked at both phytoplankton composition and optical data, I identified special characteristics in the optical signatures that correspond to a particular phytoplankton group. Although I’d have loved to see the GSO campus in person, I had a great time getting to know the Mouw Lab team (and MatLab) this summer through video conferences!


No comments yet.

Post a Comment


  • by oceanbites 3 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 4 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 5 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 7 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 9 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 9 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 10 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 10 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 11 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 11 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 12 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 12 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 1 year ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com