{"id":469,"date":"2019-10-01T09:03:02","date_gmt":"2019-10-01T09:03:02","guid":{"rendered":"https:\/\/andrea-koschinsky.org\/?page_id=469"},"modified":"2026-03-01T18:06:07","modified_gmt":"2026-03-01T18:06:07","slug":"nico-froehberg","status":"publish","type":"page","link":"https:\/\/andrea-koschinsky.org\/pt\/group-members\/nico-froehberg\/","title":{"rendered":"Nico Fr\u00f6hberg (PhD Student)"},"content":{"rendered":"
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Research Interests:<\/em><\/strong><\/p>\n\n\n\n

Processes controlling the concentration and availability of biologically relevant trace elements to the ocean (e.g. Fe\/Cu\/\/NiZn) including their behavior at transition zones like estuaries and hydrothermal systems with regards to particle adsorption, redox speciation and complexation by organic ligands.<\/p>\n\n\n\n

Lowering barriers of access to scientific research through development of low-cost open source electrochemical methods i.e. for in-situ voltammetric measurements.<\/p>\n\n\n\n

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Research project:<\/strong><\/em><\/p>\n\n\n\n

Organic complexation of Ni and other trace metals (such as Fe and Cu) in geochemical transition zones by voltammetric methods<\/em><\/p>\n\n\n\n

Within my PhD project, I am studying the behavior of trace metals, such as nickel (Ni), copper (Cu), and iron (Fe) at marine geochemical transition zones. Trace metals act as micro nutrients to marine phytoplankton and are present in such low concentrations in seawater that their availability can limit the growth of certain species, thus acting as a significant control parameter for the marine food web. At these transition zones, including estuaries, hydrothermal vents and the sediment-water interface, the investigated trace metals experience significant changes in the geochemical regime, affecting their chemical behavior as they are transported into the ocean or removed from the water column. Particularly the adsorption and desorption to\/from particulate material and the complexation by organic ligands strongly affect the fate of trace metals entering the marine geochemical system.<\/p>\n\n\n\n

I investigate these processes by analysis of different size fractions after sequential filtration and CLE-AdCSV (competitive ligand exchange \u2013 adsorptive cathodic stripping voltammetry) experiments for the determination of ligand concentrations and complexation constants. My work focusses on the analysis of water samples from hydrothermal plumes of the Kairei hydrothermal vent field as well as the Amazon river estuary.<\/p>\n\n\n\n

Method development & 3D-printing<\/em><\/p>\n\n\n\n

To improve the analytical output of my measurements, I put a lot of effort into automating the voltammetric measurements and reducing the necessary sample volume for organic complexation measurements which is often a limiting factor in marine research projects. To achieve this, I intially had a few custom components 3D-printed as prototypes by an external supplier. I quickly realized the potential of easy fabrication of custom lab supplies and components for analytical systems. THis is particularly advantageous in a trace metal lab where contamination from metal parts is a constant risk. This lead to acquisition of our own 3D-printers and I am now 3D-printing a variety of custom parts for the lab and my automated voltammetric system. While most parts are highly specialized for our particular setup, I have shared a few designs that might be useful for other labs as well here:<\/p>\n\n\n\n

https:\/\/www.printables.com\/@nfroehberg<\/a><\/p>\n\n\n\n

MARUM Trace Metal Rosette (TMR)<\/em><\/p>\n\n\n

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Recovery of the TMR aboard RV Meteor during research cruise M206 in 2024.<\/figcaption><\/figure>\n<\/div>\n\n\n

I was heavily involved in the technical concept for the trace metal rosette that was acquired by MARUM in 2023. This system is designed to obtain water samples with inimized risk of trace metal contamination from the water column of the ocean using the aramide ropes available on all the major German research vessels. These ropes do not have a conductor for active control during deployment like the steel cables used for regular sampling devices therefore requiring autonomous operation. The TMR has a titanium frame and 12 5L contamination free water samples. The control unit operates autonomously and can trigger the water samplers at pre-programmed depths or times. We have used this system very successfully to sample the hydrothermal plume at the Kairei vent field during cruise SO301 as well as the Amazon outflow during cruise M206 (see below) where I was responsible for operation of the device on board.<\/p>\n\n\n\n

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Participation in ongoing projects:<\/strong> <\/em><\/p>\n\n\n\n

RV METEOR (M206) research cruise<\/strong> to the Amazon Estuary, November-December 2024<\/strong><\/p>\n\n\n\n

During research cruise M206 (AMAZON-GEOTRACES-2) we investigate the outflow of trace metals and dissolved organic material into the Atlantic in the Amazon estuary during the dry season (as compared to the wet season sampling of the first AMAZON-GEOTRACES cruise during the wet season). During this cruise, I was responsible for the trace metal clean water column sampling and supported the station planning and on-board sample processing.<\/p>\n\n\n\n

https:\/\/andrea-koschinsky.org\/category\/m206\/<\/a><\/p>\n\n\n\n

PROBRAL sampling campaign in the mangroves near Braganca (Northeast Brazil) November 2024<\/strong><\/p>\n\n\n\n

Within the PROBRAL academic exchange project, we sampled the mangroves and rivers around Braganca in Northeast Brazil to complement our shipboard sampling of the Amazon estuary during cruise M206. For this campaign, I designed and produced large metal-free filter holders and portable peristaltic pumps that allowed us to quickly acquire filtered water samples directly in the field without risk of trace metal contamination.<\/p>\n\n\n\n

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PROBRAL<\/a><\/blockquote>