Just Keep Swimming

My Experience with Girl Talk

Who was Marie Tharp?

Marie Tharp was one of the most influential geologists and cartographers in history with an inspiring life for all women, especially those in science.

Marie Tharp (Library of Congress)

I never would have gotten the chance to study geology if it hadn't been for Pearl Harbor. Girls were needed to fill the jobs left open because the guys were off fighting.

Marie Tharp

Between the start of WWI and the end of WWII, Tharp was able to earn a bachelor's degree in English, Music, and Mathematics and a master's degree in geology.

Marie Tharp looking over ocean maps (Lamont-Doherty Earth Observatory)

Three years after WWII had ended, Marie Tharp started working at the Lamont Geological Laboratory. At the time, it was believed that the seafloor was flat and featureless. In 1952, Tharp aligned sounding profiles from Atlantis and Stewart to examine the bathymetry of the northern sections of the Mid-Atlantic Ridge. She had identified a rift valley in the middle of the Atlantic Ocean. When she told her colleague Bruce Heezen about this hypothesis, he dismissed it as "girl talk" because it would have supported the theory of plate tectonics. Only after seeing Howard Foster's map of earthquake epicenters align with Marie Tharp's map, was Heezen convinced of her hypothesis.

There's truth to the old cliches that a picture is worth a thousand words and that seeing is believing.

Marie Tharp

In 1957, Tharp and Heezen published the first map of the Atlantic, revealing its features such as canyons, ridges, and mountains. In 1977, they published the first world map of the seafloor which was a key part of proving the theory of plate tectonics.

What is Bathymetry?

Bathymetry is the science of measuring the depth of water in ocean, riverine, and lake environments. It is the study of "beds" or "floors" of water bodies. During Girl Talk, we dove into the world of bathymetry and heard from amazing women working in oceanography.

How do we map the ocean?

There are many tools we can use to map the ocean, here are some:

Using A Lead Line To Test The Water's Depth

Lead Line

The lead line is one of the first ways that sailors measured the depth of the ocean. They would take a knotted rope with a lead weight attached to one end and toss it into the ocean until the weight hits the floor. Then they would count the number of fathoms (or knots) as they pull up the rope, as a measure of depth.

Introduction to Sonar - Single Beam

Single-Beam Sonar

Single-beam sonar (Split Beam Sonar) uses a transducer that sends and receives sound pulses into the water column. It also uses a transceiver to convert the raw sound energy into usable data. This method only collects data on one spot directly under the boat.

Mapping with Multibeam Sonar | Nautilus Live

Multi-Beam Sonar

Multi-beam sonar uses beams sent across a “swath” of the ocean floor that are bounced back and processed in real time. It is similar to single-beam sonar, except it uses an array of transducers to collect data. It collects information on the seafloor depth and backscatter.

For more information on the different kinds of tools used to collect bathymetry data, you could visit this website:  https://oceanexplorer.noaa.gov/technology/technology.html 

Why do we map the ocean?

Despite covering about 70% of the Earth, only 25% of the ocean has been directly mapped. Collecting and processing bathymetry into maps that the public could access is vital for many reasons:

Ilustration made by Ruth Graham for the AORA Seabed Roadmap

How do we transform data into maps?

First, we downloaded raw bathymetry data from the NOAA's website and removed any mistakes using Qimera software. The specific survey we processed was  TN319  which is in the Pacific Ocean by the west coast of North America. We then created maps with contour lines, slopes, and rugosity using Fledermaus. Later on, our data was put together on GeoMapApp and ready to add to Google Earth.

We uploaded raw data from survey TNN319 onto Qimera to come up with a 2D image

We used Qimera to create a 3D view of the survey site

We added the seafloor data to Fiedermaus and made more maps

We added contour lines with Fiedermaus

We added a layer to show the slope of this swath

We added a layer to show the rugosity of this swath

Global movement to complete a map of the ocean

Obtaining, processing, and making bathymetry data more accessible to the public is a goal that Seabed 2030 has. I am glad to say that we have contributed to this project by processing raw data from 2 locations and adding it to GeoMapApp. Only about 25% of the ocean has been mapped.

Unmapped Ocean (GEBCO 2023)

Mapping out the west coast of South America is important to knowing how the ocean floor may interact with natural phenomenas such as ENSO.

Mapping out the Indian Ocean is important because India and other surrounding countries have a high population. It is also good to have bathymetry data of the area with monsoon data as both will affect people's livelihoods.

Mapping the ocean surrounding the Greenland ice sheet will help us better protect it from further melting and protect the animals that rely on the ice sheet.

There is still more work to be done if we wish to create a complete map of the ocean by 2030. If you'd like to know more about this global mission, read more here:  https://seabed2030.org/our-mission/ 

About Me

My second research trip to the Long Island Sound

My name is Carol Calle. I am an Ecuadorian American currently studying Environmental Science at Queens College. I love learning new things and exploring the city. Right now I am exploring different areas in Environmental Science that I like; Through the Girl Talk program, I've found that I enjoy oceanography so I will continue to explore it and see where it leads me.

Marie Tharp (Library of Congress)

Marie Tharp looking over ocean maps (Lamont-Doherty Earth Observatory)

Ilustration made by Ruth Graham for the AORA Seabed Roadmap

Unmapped Ocean (GEBCO 2023)

My second research trip to the Long Island Sound