drowning in questions about mapping the ocean? start here.

We can start by learning about the work of Marie Tharp, an American geologist and oceanographic cartographer who played a crucial role in the discovery of the Mid-Atlantic Ridge and the development of the theory of plate tectonics.

Check out the following video by National Geographic for an illustrative overview of Tharp's work!

It was thanks to Marie Tharp, a pioneer for women in her field, that the world started learning more about the ocean floor, which covers more than 70% of Earth's surface.

Scroll back to the title screen. The distinctive features on this map, illustrated by hand first by Tharp using numerous sonar readings, revealed various topographical features that would later support the Continental Drift theory and the theory of plate tectonics.

Let's take a closer look onto  Google Earth , an online software that uses satellite imagery and aerial photography to create a detailed and interactive map of the Earth. Take a moment to spin the globe and observe the oceans. What do you see?

You may notice various unique features of the seafloor, some of which are highlighted below!

These features are able to be identified thanks to collected data and measurements! Several different tools are used to survey the seafloor, often utilizing sonar waves. Sonar, short for Sound Navigation and Ranging, is useful in mapping since sound waves can travel farther into the water than radar and light waves, according to  NOAA .

There are numerous ways of measuring bathymetry, which is the measurement of depth of water in oceans, seas, or lakes. The  USGS  and  Frontiers  highlight some of the methods, as shown below:

Knowing this information can help in many ways, including:

• Resource exploration (such as gas and oil deposits)
• Understanding ocean circulation, species migration, and changing coastline features (including impacts of climate change)
• Navigation and safety to aid ships and submarines (e.g. nautical charts and hydrodynamic models)
• Building knowledge by visualizations

Yes!

SONAR data is usually reviewed to vet for false soundings during collection and processing. During the Girl Talk workshops, participants got to see measured bathymetry and filter out interrupting signals. Numerous software are available to conduct this step, including Qimera and Fledermaus.

Check out how removing the extreme outliers of deep (blue) and shallow (red) soundings clarifies the topography further:

Additionally, clearing out false soundings within a swath of collected bathymetry can improve the image of that region, as shown in the next two examples:

Through these steps, we therefore get steps closer to uncovering and mapping the mysteries of the ocean floor at better resolution! The bathymetry can also be used to examine various topographic parameters:

The global initiative of Seabed 2030 aims to bring together all available bathymetric data to produce the definitive map of the world ocean floor by 2030. If this dive into ocean mapping interests you, there are many ways to participate! Whether it be through offshore expeditions or processing data, opportunities like the following can be a great start:

•  NOAA Ocean Exploration 
•  Sea Education Association  
•  Environmental Systems Research Institute 
•  University-National Oceanographic Laboratory System 
•  Ocean Exploration Trust - Science & Engineering Internship Program  
•  WHOI - Summer Student Fellowship 
•  Woods Hole-PEP Program  

The Lamont-Doherty Earth Observatory hosts their own set of programs as well:

•  STEMSEAS  
•  Secondary School Field Research Program  
•  Polar Climate Ambassadors  

I am grateful to the Girl Talk Program for helping me begin my own journey. Through our collective efforts, we can get one step closer to de-mystifying the ocean floor!