WEBINAR – 17 July 2025, 12 noon – 12:30 CEST
A nano-scale perspective on a novel pathway for preserving hydrothermal ferrous iron
by Lotta Ternieten, Postdoctoral Fellow at Utrecht University in Utrecht, The Netherlands
EXCITE user
Lotta Ternieten looks forward to share how she utilised the facilities in the EXCITE Network to support her research. Join the webinar and learn more on how EXCITE can help you!
Summary
Lotta presents groundbreaking findings on the early transformation of iron released from hydrothermal vents at the Mid-Atlantic Ridge. Using advanced nano-scale imaging and analysis techniques, the study reveals new mechanisms that preserve bio-essential ferrous iron in the ocean, challenging the previously proposed importance of complexation with organic matter. Discover how these insights reshape our understanding of iron’s transport, bioavailability, and its wider impact on ocean chemistry.
In more detail
Hydrothermal vent systems are likely important but poorly constrained sources of (bio-essential) trace metals such as iron (Fe) to the global ocean. Key to understanding the eventual fate and biogeochemical impact of hydrothermal iron is insight into early transformation mechanisms that convert dissolved and soluble ferrous Fe(II) into insoluble ferric precipitates that are not bio-available and settle rapidly. Furthermore, interaction with other bio-essential elements, such as phosphorus, further increases the potential impact of hydrothermal iron.
In this webinar, Lotta presents recent results from the Royal NIOZ and Utrecht University joined I-NANO project aiming to determine the early transformation mechanisms of hydrothermal sourced Fe from the Rainbow (36°-33°N) hydrothermal vent field at the Mid-Atlantic Ridge. To investigate the chemical and crystallographic speciation of Fe nanoparticle aggregates, they employed a direct sampling approach that bypasses conventional techniques such as filtration and resuspension. Instead, small amounts of plume fluid were immediately drop-cast onto transmission electron microscopy (TEM) grids and plunge-frozen, preserving dissolved compounds and nanocolloids through vitrification. Using an array of microscopic and spectroscopic techniques, combined with machine learning, allowed detailed characterization of the Fe nanocolloids down to the nano-scale and provided insight into their early (trans)formation and bioavailability.
These findings shed completely new light on the transport and persistence of vent-derived reduced iron phases, highlighting the role of ferric coatings in protecting nano-scale iron sulfides and challenging the previously proposed importance of complexation with organic matter. Overall, they provide new perspectives on the early (trans)formation processes of vent-derived iron, its interaction with other essential elements, and, eventually, its impact on ocean chemistry.
