Imagine a water depth of more than 3000 meters. How
can we take samples from the boundary layer at the interface between the seabed
and the water column at such a depth? We use the Multicorer. Once that device
is safely at the bottom of the ocean, its 12 empty tubes are pushed very slowly
into the seabed. Unlike, for example, the gravity corer, which penetrates the
ocean floor with great force, compressing the transitional area from seawater
to sediment, the multicorer brings back undisturbed surface sediments with
exactly the overlying water without turbulence.

Recovering the Multicorer (2019/2019)Federal Ministry of Education and Research

Big smiles on deck: All the tubes of the multicorer are filled with sediment. Now the work begins in the lab.

Lucky! (2019/2019)Federal Ministry of Education and Research

The twelve sediment cores that the multicorer punched out of the seabed, are distributed among the different working groups in the "Polarstern" laboratory.

Here, biogeochemist Anna Lichtschlag of the National Oceanography Centre, Southampton, is carefully opening one of the tubes. What will she find in the sediments?

Sampling of a Sediment Core (2019/2019)Federal Ministry of Education and Research

Some research groups are specifically investigating the boundary layer between sediment and seawater.

Marta Torres, professor at Oregon State University's College of Earth, Ocean, and Atmospheric Sciences does not need seawater for her research, and uses a syringe to aspirate it, so that the sediments …

Fresh from the seafloor: Sampling of a Sediment Core (2019/2019)Federal Ministry of Education and Research

… can be removed layer by layer.

Fresh from the seafloor: Sampling of a Sediment Core (2019/2019)Federal Ministry of Education and Research

The precious mud from the depth …

Sample of a Sediment Core (2019/2019)Federal Ministry of Education and Research

… is being gently packed in sample bags.

Sampling of a Sediment Core (2019/2019)Federal Ministry of Education and Research

Centimeter by centimeter, the geochemistry team works hard to develop a complete profile, to determine the changes in concentrations of dissolved chemical substances. Geochemists use such concentration profiles to quantify the exchange processes between seawater and the seabed.

Concentration in the Lab (2019/2019)Federal Ministry of Education and Research

All sediments are safely packed to lie in the refrigerated container for the remainder of the cruise. The sediments will be analyzed later at the institutes onshore.

At Sea near South Georgia (2019/2019)Federal Ministry of Education and Research

The next working station. Again, the winch wire hangs in the water and takes the multicorer to the bottom of the sea.

Fresh from the seafloor (2019/2019)Federal Ministry of Education and Research

Biogeochemist Anna Lichtschlag is happy about a new, undisturbed sediment core.

This sediment is composed of millions of tiny marine animals.

Many of them form shells or skeletons made of carbonate or silicate, sinking to the bottom of the sea at the end of their short life and depositing there in the seabed.

Credits: Story

PHOTOGRAPHY: Holger von Neuhoff
TEXT: Stephanie von Neuhoff

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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