To study Earth's past climate and make predictions about future climate changes, scientists use a variety of proxy methods and materials, including fossils, ice sheets, sediments, tree rings, shells, and rocks.  For example, isotopic analysis of ice cores and biogenic carbonates can provide insights into past global temperature and sea level fluctuation. Lighter isotopes evaporate more quickly from warmer water, so shelled creatures that live in that environment tend to have shells enriched in heavier isotopes.

An additional technique for paleotemperature reconstruction is clumped isotope thermometry, which is based on the thermodynamic properties of 18O and 13C bonding and does not require knowledge of oxygen isotope ratios. In addition to carbon and oxygen isotopic composition, magnesium, strontium and calcium elemental information can help reconstruct water temperatures of the past.

Investigating climate change through ice core analysis

To investigate climate change, Thermo Fisher Scientific is partnering with the Ice Memory Foundation on the Ice Memory initiative. This global project is supported by UNESCO and aims to collect and preserve ice cores from selected glaciers currently in danger of degradation or disappearance. The ice cores are transported to Antarctica and stored in the Ice Memory cave to safeguard the information for future generations of scientists.

Changes to Earth’s climate, reflected in the chemical composition of the water in ice cores, can be investigated using ion chromatography and triple quadrupole ICP-MS. The Ice Memory Laboratory uses these techniques and Thermo Scientific instruments to analyze several thousand samples each week.

Oxygen isotope ratio analysis of water in ice cores

When water evaporates from warmer waters, the heavier oxygen isotope, 18O, is left behind, leaving the water vapor enriched in the lighter isotope, 16O. As a result, the glaciers are relatively enriched in 16O, while the oceans are relatively enriched in 18O. The difference in isotope ratio is more pronounced in colder climates than in warmer climates because the warmer temperatures allow the heavier isotopes to evaporate as well. As ice cores reflect geological time, the oxygen isotope variability in the cores can be used to reconstruct a history of past temperatures.

Changes in the oxygen isotope composition in ice layers represent changes in average ocean surface temperature. How does this work? Water molecules contain both heavy and light isotopes of hydrogen and oxygen. The water that forms glaciers (from which ice cores are taken) starts as vapor from the ocean. It then falls as snow and is compacted into ice.

Further reading

  • Triple Isotopic Composition of Oxygen in Water from Ice Cores
    Recent analytical developments have made it possible to measure the triple isotopic composition of oxygen in water with high precision. In this note, our customers concentrate on the study of δ18O, d-excess and especially the added value of 17O-excess in polar ice cores for constraining the relationship between climate and water cycle organization.
  • One Minute Separations in Ice Core Samples Using Capillary Ion Chromatography
    The chemistry of ice core samples provides insight into understanding the history of both climate change and atmospheric pollution. A key challenge for labs performing ice core analysis is minimizing the sample size of these precious ice core samples. Solution: Capillary Reagent-Free Ion Chromatography (IC).

Stable isotope ratio analysis of carbonates

Oxygen and Carbon Isotope Ratio Analysis of Carbonates

The stable oxygen isotope geochemistry of fossils, as well as sediments in aquatic and marine environments is one of the most important tools in paleoceanography and paleoclimatology. Shells from animal and plant fossils all contain oxygen (either in the form of calcium carbonate or silicon dioxide). Once the organisms die, their shells, get buried in sediments on the bottom of lakes and oceans. By drilling cores into the sediment layer, scientists collect these fossils and use them to “read” past climate.

The oxygen isotope composition in the shells of these animals can reveal how cold the ocean was and how much ice existed at the time when the shell formed. When ocean waters are cold, the shells generally contain greater proportions of heavier oxygen isotopes.

Besides oxygen isotopes, there is another isotope system that can read past climate conditions. Boron isotopes are in particularly powerful in reconstructing ancient seawater acidity, an indirect measure of atmospheric CO2 concentration. By studying boron isotope variations in foraminifera, geologists can look at past CO2 variations and how our planet is reacting to those.

In addition to measuring isotope ratios, a technique called clumped isotope thermometry has emerged as a new tool for paleotemperature constructions. This technique is based on the thermodynamic properties of 18O and 13C, which clump together, forming temperature-dependent bonds inside the carbonate. This type of thermometry does not depend upon oxygen isotope ratios.

High precision and high throughput are required for stable isotope analysis. The 253 Plus 10 kV IRMS, together with the Kiel IV Carbonate Device, is the gold standard for carbon and oxygen isotope analysis of carbonates, producing world-class data from small foraminifera samples. The Kiel IV carbonate device is a fully automated sample preparation device for dissolving carbonate material and extracting carbon and oxygen. It uses the principle of the individual acid bath for conversion of carbonates to CO2. The reaction of carbonates with phosphoric acid produces CO2 and H2O plus non-condensable gases from impurities in the sample.

The cryogenic trapping system consists of a temperature-controlled first trap with associated valves, ultra-high vacuum system, pressure gauge, and a microvolume. With the 253 Plus IRMS and Kiel IV Carbonate Device, precisions of better than 0.1 ‰ can be reached for total carbonate amounts as far down as 6 µg. Using these instruments, paleoclimatologists can resolve 0.5 °C temperature changes.

For larger samples, the GasBench Plus with the Kiel IV Carbonate Device option, combined with the 253 Plus IRMS, can be used for precise and accurate measurements of stable isotopes in forams.

Boron isotope analyses are performed by either MC-ICPM-MS or TIMS. The Thermo Scientific Neoma MC-ICP-MS and Triton series TIMS offer unique features to enable scientists to obtain high precise boron isotope ratio data within the smallest carbonate samples. Among those features are the Jet Interface and 1013 Ohm Amplifier Technology. With these low noise resistors, signal/noise is significantly improved, enabling less formaninifera to be analyzed at same levels of precisions. Even in-situ analysis is possible by coupling a laser ablation system to the Neoma series MC-ICP-MS.

Further reading

Mg/Ca and Sr/Ca as paleothermometers

Element Series HR-ICP-MS

Strontium and magnesium levels in corals are highly dependent on surrounding water temperature at the time of their deposition. This feature enables geoscientists to use Sr/Ca and Mg/Ca ratios in fossil corals as proxy indicators of past surface water temperatures. The major analytical challenge with obtaining accurate Mg/Ca and Sr/Ca elemental ratios is that these elements are present at widely different concentrations. High-resolution ICP-MS may be used to address this challenge.

Further reading

Greenhouse gases

Greenhouse gases

The sun rays warm the Earth, and the heat from the Earth travels back to the atmosphere. The gases in the atmosphere prevent some of the heat from escaping into space. These gases are called greenhouse gases, and this natural process that traps the heat in the earth’s atmosphere is known as ‘Greenhouse Effect’.

This greenhouse effect is one of the causes of global warming. The two most significant greenhouse gases in the atmosphere are carbon dioxide and water vapor. Water makes a greater contribution (about 60%) to the natural greenhouse effect. Between the absorptions caused by carbon dioxide (CO2) and water, there is a ‘window’ where the majority of the infrared radiation can escape with relatively little absorption (except for a narrow band where ozone absorbs).

About 70% of Earth’s radiation escapes into space through this ‘window.’ The other gases which cause greenhouse effect are methane, nitrous oxide (N2O), ozone, SF6, and chlorofluorocarbons (CFCs). Amongst them CO2, methane, and N2O are critically important and are being monitored for their effects in several environmental and agricultural studies all over the world. The effects of global warming are becoming more and more significant every year.

Further reading

  • Analysis of Greenhouse Gases by a Turnkey GC Analyzer System
    Greenhouse gas analysis is one of the most useful diagnostic tools in the fields of agricultural and environment monitoring. We present a specially configured gas chromatograph (GC) capable of simultaneously measuring the important greenhouse gases, including methane, CO2, and N2O, simultaneously, in a simple yet reliable manner with high accuracy and repeatability at trace levels of the component gases. The system is designed to work autonomously; hence the measurements can be made at remote stations.


Expand your analytical capabilities using a Thermo Scientific iCAP Qnova Series ICP-MS to deliver research-level trace elemental analysis and routine ease of use. User-inspired hardware and software combine in the Thermo Scientific iCAP RQplus ICP-MS to deliver maximized productivity and robustness. Simplicity and ease-of-use work in concert to streamline workflows and achieve ‘right-first-time’ results; essential to all busy labs. Harness the power of triple quadrupole (TQ) technology for uncomplicated analysis with incredible accuracy using the Thermo Scientific iCAP TQ ICP-MS.

Thermal Ionization MS

Extract high-precision isotope ratio information from your samples with the Thermo Scientific Triton Series Multicollector Thermal Ionization Mass Spectrometer (TIMS).

One means to reconstruct atmospheric CO2 concentrations from the past is by means of boron isotopes. High precision on small samples is a prerequisite for this scientific research. Both the Triton series as well as the Thermo Scientific Neoma MC-ICP-MS are ideally suited for boron isotope ratio measurements. The Thermo Scientific multicollector technology offers high sensitivity with simultaneous isotope detection.

Using MC-ICP-MS to understand our ancient world

Analysis of boron isotopic composition within foraminifera helps us reconstruct ancient seawater pH, an indirect measure of atmospheric CO2. Learn how the Neoma MC-ICP-MS simplifies this analysis.

Climate change research

We believe that studying our past climate helps us understand climate change, and provides clues that help us plan for the future.

Earth and Atmospheric Sciences at the University of Göttingen

Andreas Pack at the University of Göttingen, focusing on high precision measurements of oxygen isotope ratios in rocks, minerals and water samples.

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