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

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