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Climate Change

Climate change is one of the greatest threats to human civilisation, but determining future climate scenarios can only be built on the foundation of what we know has happened before. From understanding the variability in Earth’s climate and the possible mechanisms which drive global climate cycles, scientists have been able to develop highly sophisticated models of our future climate and are delivering crucial information to the public and government about the possible consequences of anthropogenic activity.

Stable isotope analysis works as a virtual paleo-thermometer, allowing readings of past earth temperatures in a variety of materials such as micro-fossils, ice cores and tree rings. By combining this temperature information and extrapolating into the future, we maybe able to avoid the worst outcomes and stable isotope analysis will play a crucial role in helping us do this.

Carbonate Materials

Climate signals are found throughout the seabed in the form of sedimented carbonate materials from ancient biota. The 13C and 18O isotope ratios of these materials a directly related to the ocean temperature at the time of their existence. Our Dual Inlet inlet system equipped the MultiCarb is capable of the highest precision 13C and 18O analysis of extremely small samples, as well as offering exciting new "clumped isotope" analysis.

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Ice core water analysis

The isotopic ratio of precipitation is fundamentally dependent on the temperature of the oceans it evaporates from. Ice cores from the arctic and antarctic polar regions have been recording the isotope variation for millennia making it possible to determine the temperature at the time that the ice was laid down. Our AquaPrep is able to perform the highest 18O and 2H analysis compared to any other technique, reducing uncertainty in your temperature proxy calculations.

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Greenhouse Gases

Greenhouse gases in the atmosphere are major drivers for climate change. Decoupling the anthropogenic contribution of these gases to the atmosphere from those that are the result of natural processes is vital if we are to understand the mechanisms for climate change. Using iso FLOW, you can investigate the isotopic ratios of the main greenhouse gases CO2, N2O and CH4 in atmospheric gas samples to help develop strategies to cope with climate change.

Climate change publications using our instruments

Our customers use our instruments to do some amazing research in the climate change application field. To show you how they perform their research and how they use our IRMS instruments, we have collected a range of peer-reviewed publications which cite our products. You can find the citations below and then follow the links to the publishing journal should you wish to download the publication.

If you would like to investigate our available citations in more detail, or email the citation list to yourself or your colleagues then take a look at our full citation database.

115 results:

I-n-Atei palaeolake documents past environmental changes in central Sahara at the time of the “Green Sahara”: Charcoal, carbon isotope and diatom records
Palaeogeography, Palaeoclimatology, Palaeoecology (2016)
Christophe Lécuyer, Anne-Marie Lézine, François Fourel, Françoise Gasse, Florence Sylvestre, Christine Pailles, Christophe Grenier, Yves Travi, Abel Barral

During the ‘Green Sahara event’, water bodies developed throughout the Sahara and Sahel, reflecting the enhanced influence of the Atlantic monsoon rainfall. Major lakes then dried out between 6.5 and 3.5ka. This study investigates land cover change and lacustrine environment during the Holocene at I-n-Atei, Southern Algeria, a desert region lying in the hyperarid core of the Sahara. This site is remarkable by its extent (up to 80km2) and by the exceptional preservation and thickness of the lacustrine deposits (7.2m). I-n-Atei was a lake from 11 to 7.4ka, then it dried out and left place to a swampy environment. Charcoal concentrations show that the surroundings of the lake were vegetated throughout the wet period with two short phases of possible vegetation deterioration associated with a lowering of the lake level at 9.3 and 8.2ka, coeval with well-known dry events in the tropics. The stable carbon isotope record reflects the penetration of C4 herbaceous populations in replacement of the original C3, typical of the regional vegetation at the time of the maximum lake expansion. The δ13C of charcoals increase non-linearly with the 14C-based ages from −24.5‰ to −13.0‰ (V-PDB). Assuming that these extreme values sample both C3 and C4 plant end-members, mass balance calculations suggest that C3 were replaced by C4 plants according to an exponential decay law with a half-life (t1/2) of 850±110years. The replacement of C3 by C4 plants occurred in two main steps: a mixed C3–C4 vegetation of “wooded grassland” type was present from 10ka to 8.4ka while a C4 exclusive vegetation developed after 8.4ka. After the end of the lacustrine phase a catastrophic event (flooding?) provoked the lifting of most of the lacustrine deposits and their re-deposition above the lacustrine sequence.

Palaeotemperature reconstruction during the Last Glacial from δ18O of earthworm calcite granules from Nussloch loess sequence, Germany
Earth and Planetary Science Letters (2016)
Charlotte Prud'homme, Christophe Lécuyer, Pierre Antoine, Olivier Moine, Christine Hatté, François Fourel, François Martineau, Denis-Didier Rousseau

The Nussloch loess–palaeosol sequence (Rhine Valley, Germany) is considered to be one of the most complete records of the last glacial period in Western Europe due to its very high sedimentation rate and its good chronological control. This sequence is therefore a good framework in which to develop new proxies for palaeoenvironmental reconstructions. In this study, we explore, for the first time, the potential of earthworm calcite granules as a new bio-indicator and climatic proxy of absolute air and soil temperature in the context of Last Glacial loess. These granules are composed of rhomboedric calcite crystals, organized in a radial crystalline structure. As these granules are individually generated by earthworms at a relative fast rate, they are expected to record intra-annual variations in the available sources of oxygen: percolating waters of meteoric origin. We extracted thirty earthworm calcite granules from 11 of 5 cm layers thick from tundra gley and brown soil horizons previously, dated at 45 to 23 ka. Oxygen isotope ratios were measured on each individual granule. The δ18O of calcite granules and interlinked transfer functions between water cycle, air and soil temperatures allowed us to estimate air temperatures ranging from 10 to 12 ±4 ◦C, which most likely reflect the warm periods of the year when earthworms were the most active.
Tags: oxygen , geol , clim , mulitcarb

Coupling of marine and continental oxygen isotope records during the Eocene-Oligocene transition
Geological Society of America Bulletin (2016)
Nathan D. Sheldon, Stephen T. Grimes, Jerry J. Hooker, Margaret E. Collinson, Melanie J. Bugler, Michael T. Hren, Gregory D. Price, Paul A. Sutton

While marine records of the Eocene-Oligocene transition indicate a generally coherent response to global cooling and the growth of continental ice on Antarctica, continental records indicate substantial spatial variability. Marine Eocene-Oligocene transition records are marked by an ~+1.1{per thousand} foraminiferal {delta}18O shift, but continental records rarely record the same geochemical signature, making both correlation and linking of causal mechanisms between marine and continental records challenging. Here, a new high-resolution continental {delta}18O record, derived from the freshwater gill-breathing gastropod Viviparus lentus, is presented from the Hampshire Basin, UK. The Solent Group records marine incursions and has an established magnetostratigraphy, making it possible to correlate the succession directly with marine records. The V. lentus {delta}18O record indicates a penecontemporaneous, higher-magnitude shift (>+1.4{per thousand}) than marine records, which reflects both cooling and a source moisture compositional shift consistent with the growth of Antarctic ice. When combined with "clumped" isotope measurements from the same succession, about half of the isotopic shift can be attributed to cooling and about half to source moisture change, proportions similar to marine foraminiferal records. Thus, the new record indicates strong hydrological cycle connections between marine and marginal continental environments during the Eocene-Oligocene transition not observed in continental interior records.

Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica : further insights for biomarker-based paleo sea-ice reconstruction
Organic Geochemistry (2016)
Lukas Smik, Simon T Belt, Jan L Lieser, Leanne K Armand, Amy Leventer

The occurrence and variable abundance of certain di- and tri-unsaturated C25 highly branched isoprenoid (HBI) biomarkers in Antarctic marine sediments has previously been proposed as a possible proxy measure of paleo sea-ice extent in the Southern Ocean. In the current study, we obtained 47 near-surface (ca. 0–10 m) water samples taken from locations in East Antarctica with different sea ice settings and analysed them for their HBI, sterol and fatty acid content. Sampling locations ranged from the permanently open-ocean zone (POOZ), with no seasonal sea-ice cover, the near-shore summer sea ice zone (SIZ), where sea ice remains long into the summer melt season, and the marginal ice zone (MIZ), located between the POOZ and the SIZ, and with a highly variable latitudinal sea-ice edge throughout the season. A di-unsaturated C25 HBI (diene II) was only identified in surface waters from the MIZ and the SIZ, consistent with a sea-ice diatom origin for this biomarker. In contrast, a tri-unsaturated C25 HBI (triene III) was detected in all samples from the POOZ, the MIZ and the SIZ, and with a stable isotopic composition (δ13C = –35 ± 1.5‰) consistent with a phytoplankton source. The highest concentrations of diene II and triene III were in samples from the SIZ and the MIZ, respectively, thus providing further insights into the sea-ice conditions likely favourable for their production and how their relative abundances (the II/III ratio) in underlying sediments might be better interpreted for paleo sea-ice reconstruction. In this respect, relatively high II/III might be a good indicator of extended (into summer) seasonal sea-ice cover, while lower II/III may provide a better indicator of the MIZ. However, the observation of highly variable II/III within the polynya setting of the SIZ may also have 4 significant impacts on sedimentary values. Distributions of diatom sterols and fatty acids were also variable between the three sampling zones, but these were not as distinctive as those observed for the HBIs
Tags: carbon , ocea , clim , gaschrom

Soil organic carbon content affects the stability of biochar in paddy soil
Agriculture, Ecosystems & Environment (2016)
Mengxiong Wu, Xingguo Han, Ting Zhong, Mengdong Yuan, Weixiang Wu

Recalcitrant biochar application appears to be a promising method to decelerate global warming through increasing long-term carbon sequestration in soil. Stability of biochar carbon (C), which is the major determining factor of C sequestration effect, depends mainly on biochar physiochemical characteristics and soil properties. However, little is known about biochar C stability in paddy soil. In this study, 13C labeled rice straw (RS) biochar produced at 500°C was incubated with five types of paddy soils to determine the key soil characteristics involved in biochar-C stability. Results showed that cumulative mineralization rates of RS biochar-C incubated with different paddy soils were relatively low (0.17–0.28%) during 390days of incubation. The cumulative mineralization rates of RS biochar-C increased with the increasing native soil total organic carbon (TOC) content. The estimated mean residence time (MRT) of stable C components of RS biochar in paddy soil, varying from 617 to 2829 years, decreased with the increase of soil TOC content. In addition, greater atomic O/C ratio and oxygen-containing functional groups were observed in biochar samples incubated in paddy soils with higher TOC content. These results suggest that RS biochar application could be an effective method for C sequestration in paddy soil. However, the stability of RS biochar in paddy soil would be significantly impacted by soil TOC content. From the perspective of long-term C sequestration, RS biochar is more suitable for applying in paddy soils with lower TOC content.

Stable oxygen isotope signatures of early season wood in New Zealand kauri (Agathis australis) tree rings: Prospects for palaeoclimate reconstruction
Dendrochronologia (2016)
Andrew M. Lorrey, Tom H. Brookman, Michael N. Evans, Nicolas C. Fauchereau, Cate Macinnis-Ng, Margaret M. Barbour, Alison Criscitiello, Greg Eischeid, Anthony M. Fowler, Travis W. Horton, Daniel P. Schrag

One of the longest Southern Hemisphere tree ring chronologies that has potential to provide past climate reconstructions has been produced using New Zealand kauri (Agathis australis). Work to date on kauri has been limited to reconstructions from whole-ring width analysis. In this study, we present the first replicated stable oxygen isotopic composition of early season alpha-cellulose from calendar-dated kauri tree rings within the natural growth range of the species. We also use newly established kauri physiology information about stomatal conductance and a mechanistic model to place initial interpretations on kauri δ18O signatures. Kauri early season δ18O has a range from 26 to 34‰ (V-SMOW) for a site located at Lower Huia Dam in west Auckland, and the mean δ18O chronology from that site is significantly correlated (p<0.05) to October-December vapor pressure, May-December relative humidity and other associated hydroclimatic variables. The observed statistical relationships are consistent with mechanistic δ18O simulations using the forward model of Barbour et al. (2004) that incorporates a leaf temperature energy balance model to calculate transpiration as forced with local meteorological variables and a range of physiological parameters. The correlation results and mechanistic model simulations suggest kauri δ18O early season wood has the potential to provide new quantitative past climate information for northern New Zealand, and also complement whole ring-width reconstructions of past regional climate variability – a component of which is previously established as sensitive to El Niño-Southern Oscillation activity. Additional work is required to determine whether the observed relationships are consistent across the growth range of kauri and what the optimum sample depth is before long isotope-based palaeoclimate reconstructions from modern and sub-fossil kauri sites are undertaken.

ENSO variability around 2000 years ago recorded by Tridacna gigas δ18O from the South China Sea
Quaternary International (2016)
Hong Yan, Chengcheng Liu, Wenchao Zhang, Ming Li, Xufeng Zheng, Gangjian Wei, Louhua Xie, Wenfeng Deng, Liguang Sun

El Niño–Southern Oscillation (ENSO) is the most important mode of interannual changes in global climate. The knowledge of ENSO variability in different mean climate conditions is essential for us to understand the ENSO mechanism and predict its future trend in a warming world. Here we present a 50-year-long, monthly resolved oxygen isotope record, obtained from a 14C dated (AD 50 ± 40) fossil giant clam, Tridacna gigas, located on Dongdao Island, South China Sea, where the interannual climate anomaly is dominated by ENSO variations. We developed a quantitative method to extract the ENSO events from the regional Sea Surface Temperature (SST) and oxygen isotope records. And then, the ENSO variations about 2000 years ago, located in the so called Roman Warm Period, was calculated from the oxygen isotope series of fossil T. gigas. Our quantitative record shows that ENSO variance in Roman times was similar to the instrumental times, with a total of 11 El Niño events and 12 La Niña events within 50 years.
Tags: carbon , oxygen , ocea , clim , mulitcarb

Similar temperature responses suggest future climate warming will not alter partitioning between denitrification and anammox in temperate marine sediments.
Global change biology (2016)
Lindsay D Brin, Anne E Giblin, Jeremy J Rich

Removal of biologically available nitrogen (N) by the microbially mediated processes denitrification and anaerobic ammonium oxidation (anammox) affects ecosystem N availability. Although few studies have examined temperature responses of denitrification and anammox, previous work suggests that denitrification could become more important than anammox in response to climate warming. To test this hypothesis, we determined whether temperature responses of denitrification and anammox differed in shelf and estuarine sediments from coastal Rhode Island over a seasonal cycle. The influence of temperature and organic C availability was further assessed in a 12-week laboratory microcosm experiment. Temperature responses, as characterized by thermal optima (Topt ) and apparent activation energy (Ea ), were determined by measuring potential rates of denitrification and anammox at 31 discrete temperatures ranging from 3 to 59°C. With a few exceptions, Topt and Ea of denitrification and anammox did not differ in Rhode Island sediments over the seasonal cycle. In microcosm sediments, Ea was somewhat lower for anammox compared to denitrification across all treatments. However, Topt did not differ between processes, and neither Ea nor Topt changed with warming or carbon addition. Thus, the two processes behaved similarly in terms of temperature response, and this response was not influenced by warming. This led us to reject the hypothesis that anammox is more cold-adapted than denitrification in our study system. Overall, our study suggests that temperature responses of both processes can be accurately modeled for temperate regions in the future using a single set of parameters, which are likely not to change over the next century as a result of predicted climate warming. We further conclude that climate warming will not directly alter the partitioning of N flow through anammox and denitrification. This article is protected by copyright. All rights reserved.
Tags: nitrogen , ocea , clim , gashead

Paleoenvironmental reconstruction of the Late Santonian Songliao Paleo-lake
Palaeogeography, Palaeoclimatology, Palaeoecology (2016)
Huairen Cao, Jianfang Hu, Ping’an Peng, Dangpeng Xi, Youjun Tang, Yan Lei, Andrea Shilling

The Late Cretaceous is often characterized as having a variable greenhouse climate, however, the relatively few continental sites preserving geologic records from this time exist limiting information on terrestrial climate and environments. Worldwide, the Songliao Basin (SLB) of northeastern China is one of the largest Cretaceous-age continental rift basins. Thus, this well-preserved lacustrine deposit provides a unique record of terrestrial paleoenvironmental conditions during the Cretaceous. Here, we report organic geochemical data from Late Cretaceous-age lacustrine deposits (lower Nenjiang Formation) from the eastern side of the SLB. Outcrop samples were collected from the Houjingou section and the following analyses performed: (1) total organic carbon (TOC) content and isotopic composition, (2) biomarker distribution, including the identification and determination of relative amounts of both aliphatic and aromatic hydrocarbons and steranes, and (3) compound specific stable carbon and hydrogen isotopic compositions of n-alkanes. The biomarker distribution and stable carbon isotopic values (δ13C) of the TOC indicate organic matter (OM) from the uppermost section of the first member of the Nenjiang Formation (Upper K2n1) was mainly sourced from aquatic macrophytes and land plants. In the lower part of the second member of the Nenjiang Formation (Lower K2n2) the biomarker distribution and δ13C of both the TOC and n-alkanes indicate that OM was sourced from a mixture of algae, bacteria, and higher plants. As a result of marine transgression, seawater incursions, indicated by the presence of 24-n-propyl-cholestanes and 24-iso-propyl-cholestanes, occurred episodically in Lower K2n2. The negative hydrogen isotopic composition (δ2H) of short chain n-alkanes in Lower K2n2 indicate an extremely humid environment and it is likely that an influx of freshwater caused large-scale flooding of the Songliao Paleo-lake. High-resolution biomarker and stable isotope records from the Houjingou section demonstrate abrupt environmental changes in the Songliao Paleo-lake following seawater incursions during the Late Cretaceous.

The Late Cryogenian Warm Interval, NE Svalbard: chemostratigraphy and genesis
Precambrian Research (2016)
Ian J. Fairchild, Pierre Bonnand, Tesni Davies, Edward J. Fleming, Nathalie Grassineau, Galen P. Halverson, Michael J. Hambrey, Emily M. McMillan, Elizabeth McKay, Ian J. Parkinson, Carl T.E. Stevenson

The Late Cryogenian Warm Interval (LCWI) refers to a non-glacial interval that separates presumed representatives of the Sturtian and Marinoan panglaciations. Its duration is poorly constrained radiometrically and its deposits are relatively poorly known in most geographic regions. This paper aims to constrain the duration, palaeoenvironments and petrogenesis of such deposits in the classic region of NE Spitsbergen, Svalbard. The succession comprises a 200-205 m dolomitic shale (Macdonaldryggen Member, known as E3, of the Elbobreen Formation) overlain by oolitic dolomite Slangen Member (E4), 15-25 m thick, with limestone developed at top and base of E3 in the south of the area. The assumed age context of the succession has been confirmed by the presence of a typical Sturtian cap carbonate profile of negative to positive δ13C, and primary Sr isotope compositions of basal E3 limestones <0.7072 and of upper E3 limestones of 0.7076. At the base of E3, interstratification of cap carbonate with ice-rafted and redeposited glacial sediments occurs. Early diagenetic stabilization of carbonate mineralogy from a precursor, possibly ikaite, to calcite or dolomite is inferred. E3 is predominantly dolomitic silt-shale, with sub-millimetre lamination, lacking sand or current-related sedimentary structures. Thin fine laminae are partly pyritized and interpreted as microbial mats. Dolomite content is 25-50%, with δ13C values consistently around +4‰, a value attributed to buffering by dissolution of a precursor metastable carbonate phase. Local calcite cement associates with low δ13C values. The carbonates form silt-sized, chemically zoned rhombic crystals from an environment with dynamically changing Fe and Mn. Three-dimensional reconstructions of cm-scale disturbance structures indicate that they represent horizontally directed sock-like folds, developed by release of overpressure into thin surficial sediment overlying an early-cemented layer. A shoaling upwards unit near the top of E3 displays calcium sulphate pseudomorphs in dolomite in the north, but storm-dominated limestones in the south, both being overlain by peritidal oolitic dolomites, exposed under the succeeding Wilsonbreen glacial deposits. There is no Trezona δ13C anomaly, possibly implying top-truncation of the succession. Regular 0.5 m-scale sedimentary rhythms, reflecting subtle variations in sediment texture or composition occur throughout E3 and are interpreted as allocyclic. They are thought to be mainly primary in origin, locally modified slightly during early diagenetic cementation. Rhythms are proposed to represent ca. 18 kyr precession cycles, implying 6-8 Myr deposition between glaciations.