Simulating natural environments

Current knowledge on how mineral dissolution or precipitation can increase ocean alkalinity is largely based on laboratory experiments in seawater under ideal conditions. However, one of the main differences between a laboratory and natural coastal environments is the physical and biological processes that affect weathering in nature. The Geobiology lab aims to bridge the gap between laboratory and natural conditions.

Waves and currents cause sediment grains to collide continuously, abrading the surfaces of particles. As a result, particle dissolution—and the associated alkalinity release—may be higher in natural settings than what is observed in idealized laboratory experiments.

The Coastal Ocean Alkalinization team can set up large-scale experiments using up to 30 rolling tables to investigate how grain-tumbling speed influences alkalinity release in natural seawater and to compare collision-driven dissolution across different silicate minerals.

When studying ocean alkalinization, it is important to thoroughly understand the conditions that affect this natural process. Microcosms are small-scale laboratory incubators that isolate a layer of natural sediment and overlying seawater. They allow us to control experimental conditions to identify natural drivers of alkalinity production.

The team at University of Antwerp is currently carrying out three types of microcosm experiments. Flow-through incubators simulate coarse sediments with high flushing of the porewater, rotor incubators simulate medium fine sediments that have limited porewater flushing and core incubators simulate fine sediments without porewater flushing.

A unique mesocosm infrastructure dedicated to enhanced weathering research was built by the University of Antwerp in Ostend (Belgium) in 2013. It is now the longest-running coastal enhanced weathering setup in the world.

Today, the facility includes 20 mesocosms, each representing one square meter of North Sea seafloor. Every tank contains a 40 cm layer of North Sea sediment and around 500 L of seawater. In most tanks, lugworms (Arenicola marina) were introduced to mimic natural bioturbation.

The main purposes of this setup are to assess how effectively the fast-weathering silicate mineral olivine can capture CO₂ and to study the dissolution and CO₂ uptake capacity of mussel shells under natural conditions.

The Mesocosm operations are funded by Blauwe Cluster (01/2024 - 04/2027), Carbon Time Odyssea (11/2022 – 12/2025) and FWO (SBO, 01/2019 – 12/2022).