Foraminifera Culturing Laboratory: Growing tiny climate archives in Arctic Norway

The Foraminifera Culturing Laboratory gives researchers rare access to living polar plankton, controlled experiments and the tools needed to understand the past and future of the Arctic Ocean.

Scientists preparing for a hotter world need to know how the Arctic Ocean responded during past warm periods. Marine sediments can extend that record back thousands, hundreds of thousands or even millions of years. But those records are only as good as the methods used to interpret them - methods in which tiny creatures called foraminifera play a leading role.

Foraminifera are single-celled organisms that build calcium carbonate shells from seawater. After death, their shells can sink to the seafloor and become part of marine sediments. Long afterwards, shell chemistry can still preserve clues about temperature and water chemistry in the ocean they lived in.

Those clues are invaluable, but reading them is not simple. A shell is not a thermometer. It is made by a living organism with its own biology. To understand the signals recorded in fossil shells, scientists first need to understand how living foraminifera grow under known conditions, and how environmental information is encoded and preserved in their shells.

That is where the Foraminifera Culturing Laboratory in Tromsø comes in.

Built for controlled experiments

The lab is designed for experiments that require careful control of temperature, light and water chemistry. Key equipment and features include:

·       Two connected temperature-controlled rooms for foraminifera culturing experiments, operating down to 2°C and able to run at different temperatures.

·       Three Friocell Evo 222 incubators for experiments down to freezing temperatures while maintaining controlled light.

·       These have programmable light and temperature cycles that can mimic natural ocean conditions, including day-night cycles with varying light intensity.

·       A variety of working spaces including for microscopy, benches for culture preparation and feeding, sinks, drains and room for additional instruments.

·       On-site treatment water preparation facilities, including a fume hood and chemical cabinet. 

·       A digital meter for measuring pH, salinity, temperature, and dissolved oxygen.

·       Two inverted transmitted light microscopes with high-definition colour cameras, including fluorescence capability.

·       These are imaging tools for e.g., observing, photographing, filming and making time-lapse videos of living foraminifera.

·       Three transportable stereo microscopes for laboratory- and cruise work. 

“The strength of the lab is that it lets us bring some aspects of the ocean environment into a controlled setting,” says Mohamed Ezat, who leads the laboratory. “By carefully changing temperature, light and water chemistry, we can observe how living foraminifera respond, grow and build their shells, and investigate how environmental and biological signals are incorporated, modified and preserved in the shell. That gives us a much stronger foundation for interpreting the fossil record.”

A living laboratory for past oceans

Foraminifera are widely used in paleoceanography. Their shell chemistry can help reconstruct past ocean temperatures, carbonate chemistry and other environmental conditions.

At the heart of the lab’s work is a deceptively simple idea: if researchers can grow foraminifera under controlled conditions, they can better interpret fossil shells preserved in marine sediments.

But culturing foraminifera is demanding. It begins at sea, with the collection of living specimens from polar and subpolar waters, and continues in the lab, where researchers monitor delicate organisms, analyse them with microscopy and geochemistry. Later, they connect the results back to sediment records and climate models.

Recent laboratory culture work at iC3 has shown that shell chemistry can be shaped by biological processes.

A study led by Adele Westgård found that foraminifera grown under controlled conditions developed an outer crust with a different chemical signature from the shell beneath it, even though both formed under the same environmental conditions.

“Culturing gives us a rare opportunity,” Adele explains. “We can watch the organism build its shell under known conditions. Some fossil shells may contain more than one chemical story. Culturing helps separate those stories.” 

Research led by Freya Sykes also showed why culturing matters. Her team found that shell size alone may not reveal whether a fossil shell records short-term conditions or a longer stretch of ocean history.

“The exciting thing about culturing is that it lets us see the living behaviour behind the fossil signal,” says Freya. “Once we understand how these organisms grow, survive and build their shells, we can read past ocean change with much more confidence.”

Other recent work at the lab includes experiments on Globigerina bulloides, Neogloboquadrina pachyderma, Neogloboquadrina incompta, and Turborotalita quinqueloba, testing responses to salinity, pH, temperature, carbonate ion concentration and barium concentration.

Invitation to collaborators

The lab has already hosted visiting researchers and students working on respiration, reproduction strategies, marine snow, Ba/Ca in planktonic foraminifera, Nordic Seas assemblages, genetic diversity and paleo-proxy development.

For external researchers, the lab offers more than equipment. It is part of the wider iC3 research community of over 50 scientists whose activities connect polar fieldwork, laboratory experiments, proxy development, marine biology, climate science and modelling.

The Foraminifera Culturing Laboratory is now open to collaborations that align with its focus on foraminifera culturing, proxy development, plankton biology and polar paleoceanography. 

The lab is led by iC3’s Mohamed Ezat as part of ARCLIM, a multidisciplinary project combining marine ecology, geochemistry and climate modelling to understand how oceans and the global climate interacted during past warm periods. Please contact him for more information.