August 16, 2025

PRESSURISED: 061 – Trench nutrient cycling with Ronnie N. Glud

32 minutes

Welcome to the PRESSURISED version of episode 61, just the science, none of the waffle

PRESSURISED: Trench nutrient cycling with Ronnie N. Glud | The Deep Sea Podcast | Episode 61

Guest Interview: Nutrient cycling in the hadal trenches (6 to 11 km) and the crucial role they play in global element cycling. Professor Ronnie N. Glud, a leading biochemist and Director of the Danish Centre for Hadal Research (HADAL) talks us through how the trenches, once thought to be barren, are actually "dynamic deep-sea hotspots with intensified microbial activity and diversity". Learn about:

How hadal trenches act as "depocenters" for organic material, leading to microbial activity that's 2 to 6 times higher than in adjacent abyssal sites.

The surprising diversity of microbial "generalists" that easily adapt to the immense pressure and low temperatures, aided by viruses that facilitate "horizontal gene transfer".

The return of full anaerobic diagenetic processes (like sulphate reduction and anammox) in trench sediments, making them significant sinks for fixed nitrogen.

The role of marine snow and seismic activity in efficiently transporting organic matter and, surprisingly, pollutants like PCBs and heavy metals to these remote depths.

Why these trenches are not isolated environments but are highly connected to surface ocean processes, even responding to climate-driven changes in primary production.

We also have a surprise blobfish guest!

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Reference list

Flourishing chemosynthetic life at the greatest depths of hadal trenches

Element cycling and microbial life in the hadal realm

Credits

Theme: Hadal Zone Express by Märvel

Logo image: Ronnie N. Glud

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By Thomas Linley

4646 ratings