In Our Time: Science

The Mariana Trench

Feb 19, 2026
Alan Jamieson, deep-submergence explorer and hadal ecologist. Jon Copley, ocean exploration and deep-sea biology communicator. Heather Stewart, marine geologist specializing in subduction trenches. They describe descending into the Mariana Trench, engineering challenges of hadal exploration, trench geology and sediment flows, bizarre deep-sea life like snailfish, pervasive human debris, and the science and conservation questions that keep researchers returning.
Ask episode
AI Snips
Chapters
Books
Transcript
Episode notes
INSIGHT

Mariana Trench Formation And Visuals

  • The Mariana Trench is a 2,550 km long subduction trench formed where the Pacific plate dives under adjoining plates, creating depths to 10,925 metres.
  • Heather Stewart described visible seafloor features from hemipelagic clays to exposed mantle and carbonate vent chimneys like Shinkai.
ANECDOTE

Unplanned Dive Found Sulphur Mounds

  • Alan Jamieson described an unplanned dive to Serenity at ~10,700 m where they found big sulphur mounds and surprising geology.
  • He emphasised several successful deep dives in a short series when no one expected multiple trips would work.
INSIGHT

Engineering Limits Are Pressure And Communication

  • Deep submersibles face two core challenges: immense static pressure and long-distance acoustic communication with the surface.
  • Alan Jamieson explained pressure is handled by thick titanium spheres while acoustic modems and undersea tracking are the harder problems.
Get the Snipd Podcast app to discover more snips from this episode
Get the app