Stable Isotope Ratio Facility For Environmental Research Paper

Stable Isotope Geosciences Facility

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Established on the TAMU campus in College Station in 2009, the Stable Isotope Geosciences Facility is designed to provide accessible, reliable and high-quality stable isotope measurements and training for faculty, staff and students within the College of Geosciences and the Texas A&M community. It was also created as a facility where state-of-the-art methodologies and technological developments in stable isotopes could be applied to important societal problems related to energy, ecology, Earth history, and the environment.

Beyond the TAMU community, the SIGF has strong research links with scientists and students from other universities and industry who require precise measurements. The facility continues to be recognized for its quality work and research, and to operate on the core values of Texas A&M University.

SIGF announces the Stable Isotope Partnership for Ecology, Environment, and Energy Research (SIPEEER)

The Stable Isotope Geosciences Facility(SIGF) in the College of Geosciences, and the Stable Isotopes for Biosphere Science (SIBS) Laboratory in the College of Agriculture and Life Sciences have teamed up to better integrate the two light stable isotope ratio facilities on campus, and to add needed capabilities to serve the greater TAMU and regional community.  Funded by a $5 million initiative from the Chancellor’s office to support mass spectrometry, SIGF and SIBS will share $1 million to purchase four new instruments: a clumped isotope mass spectrometer (CIMS) and a gas chromatograph-combustion-isotope ratio mass spectrometer system (GC-C-MS-IRMS), and two additional IRMS to couple with Elemental Analyzers and other peripherals, delivering to TAMU a stable isotope capability unmatched in Texas and the region.

The clumped isotope mass spectrometer (CIMS) measures the concentration of molecules with two rare isotopes, for example, 13C18O16O/12C16O2. This ratio in carbonate rocks and minerals is temperature dependent, providing a geothermometer for pore-filling carbonate cements, sedimentary basin temperatures, and ocean and terrestrial paleoclimate studies. The CIMS would be housed at SIGF. A second instrument, the GC-C-MS-IRMS, separates and identifies compounds with gas chromatography and quadrupole mass spectrometry, then quantifies isotopic composition through a combustion or pyrolysis interface to an IRMS. This system would provide cutting-edge capabilities to track sources and fates of specific biochemical compounds through the biosphere, geosphere, hydrosphere, and atmosphere, expanding the interpretation of bulk isotopic measurement. The instrument would be housed in the SIBSLaboratory. 

NIWA's state of the art Stable Isotope Mass Spectrometry (IRMS) facility supports our research and commercial analyses, providing tailor-made solutions for various environmental and atmospheric questions. Our purpose-built facility houses high precision Thermo Fisher Scientific (MAT252, MAT253 and Delta V Plus) and Isoprime mass spectrometers, equipped with peripheral devices capable of analysing carbon, nitrogen, oxygen, hydrogen and sulphur isotopes in air, water, organic and inorganic samples.

Our stable isotope facility staff specialise in methods developments and novel technological advances. We encourage research collaboration with our colleagues and clients, and aim to work together as a team to facilitate the best project outcomes. We are happy to provide advice and assistance with projects from conception to publication, and recommend contacting the relevant staff listed in the table below to address research and analytical queries.

 

Mass Spectrometry techniques and measurements 

[MD] indicates that methods development is required before this method is available to clients
 AnalysisInstrumentPeripheralContact Person
Airδ13C of CO2 in airMAT-252GC-IRMSGordon Brailsford
 δ13C of CO2 in airDelta V PlusGasbench II & Precon[MD]Sarah Bury
 δ18O of CO2 in airMAT-252GC-IRMSGordon Brailsford
 δ18O of CO2 in air Delta V PlusGasbench II & Precon[MD]Sarah Bury
 δ13C of CH4 in airMAT-252GC-IRMSGordon Brailsford
 δ13C of CH4 in airDelta V PlusGasbench II & PreconSarah Bury
 δ2H of CH4 in airDelta V PlusGasbench II & Precon[MD]Sarah Bury
 δ15N of N2 in airDelta V PlusGasbench II & Precon[MD]Sarah Bury
 δ15N of N2O in airDelta V PlusGasbench II & Precon
Sarah Bury
 δ18O of N2O in airDelta V PlusGasbench II & Precon[MD]Sarah Bury
 δ18O of O2 in airDelta V PlusGasbench II  [MD]Sarah Bury
     
Carbon Dioxideδ13C of CO2MAT-253Dual InletGordon Brailsford
 δ18O of CO2MAT-253Dual InletGordon Brailsford
     
Carbon Monoxideδ13C of COMAT-252Dual InletGordon Brailsford
     
Nitrous Oxideδ15N of N2ODelta V PlusGasbench II & Precon[MD]Sarah Bury
 δ18O of N2ODelta V PlusGasbench II & Precon[MD]Sarah Bury
     
Waterδ2H of waterDelta V PlusGasbench II/TCEASarah Bury
 δ18O of waterDelta V PlusGasbench II/TCEASarah Bury
 δ18O of dissolved oxygen in waterDelta V PlusGasbench II[MD]Sarah Bury
 δ13C of DIC*Delta V PlusGasbench IISarah Bury
 δ15N of dissolved N2 in waterDelta V PlusGasbench IISarah Bury
     
Carbonatesδ13C of carbonateMAT 253Kiel IVAndrew Kingston
 δ13C of carbonateDelta V PlusGasbench IISarah Bury
 δ18O of carbonateMAT 254Kiel IVAndrew Kingston
 δ18O of carbonateDelta V PlusGasbench IISarah Bury
     
Organics (tissue, filters, sediment)δ13C of organicsDelta Plus/
Delta V Plus
NA1500/
Flash 2000 EA
Sarah Bury
 δ15N of organicsDelta Plus/
Delta V Plus
NA1500/
Flash 2000 EA
Sarah Bury
 δ34S of organicsDelta Plus/
Delta V Plus
NA1500/
Flash 2000 EA
[MD]Sarah Bury
 δ18O of organicsDelta V PlusTCEASarah Bury
 δ2H of organicsDelta V PlusTCEASarah Bury
     
Compound Specific Isotope Analysisδ15N of Amino AcidsDelta V PlusGC-IsolinkBrittany Graham/Andrew Kingston
 δ13C of Amino AcidsDelta V PlusGC-IsolinkBrittany Graham/Andrew Kingston
 δ13C of Fatty AcidsDelta V PlusGC-IsolinkBrittany Graham/Andrew Kingston
 δ13C, δ15N or δ2H of additional compoundsDelta V PlusGC-Isolink[MD]Brittany Graham/Andrew Kingston
* DIC dissolved inorganic carbon

Research areas

Our analytical facility generates isotope data which supports numerous research areas, which link into the following National Centres within NIWA: Aquaculture; Climate, Atmosphere & Hazards; Coasts and Oceans; Fisheries; Freshwater & Estuaries.

Atmospheric Greenhouse gas studies 

Atmospheric greenhouse and trace gases are measured on the MAT252 and MAT253 utilising both dual inlet and continuous flow. While paleo-atmospheres are studied from ice cores on the Isoprime using a continuous flow technique.

NIWA operates Thermo Scientific MAT252 and MAT253 isotope ratio mass spectrometers in a purpose-built laboratory at Greta Point, Wellington. These instruments are fitted with both continuous flow and dual inlet systems and have been modified to provide precise analyses for various aspects of the environmental research undertaken by NIWA and its clients. In particular, modifications have been made to enable high-precision determinations of δ13C in the atmospheric greenhouse gases, carbon dioxide (CO2) and methane (CH4), as well as the trace gas carbon monoxide (CO). These data have been widely used in studies of the source structure of the gases as well as models examining global climate change.

Carbon dioxide is currently increasing in the atmosphere. While precise concentration measurements allow us to track this increase, it is stable isotopes that allow us to observe how the composition of the atmospheric CO2 is changing. The CO2 analyses involve the online separation of whole air on a chromatographic column, before measurement in a continuous flow mode. These analyses provide both δ13C and δ18O, with precisions of 0.02‰ and 0.04‰ respectively.

Methane is the second most important greenhouse gas. Research into the stable carbon isotope seasonality and variability provides insight into methane sources, atmospheric processes and transport. Methane isotope analyses at NIWA involve either off-line preparation for high precision, or are made on-line for small samples. The high precision analyses are aimed at resolving the small seasonal cycle (about 0.2 ‰) observed at southern mid-latitudes. Our off-line preparation achieves repeatability of better than 0.02‰ since the early 1990s. Scientific findings, based on this time series, include the characterisation of a previously unknown methane sink, and a recent shift in global methane sources from fossil fuels to wetlands or agriculture.

The study of paleo-atmospheres using ice cores is constrained by very small sample sizes. For this reason the continuous flow Isoprime is fitted with a pre-concentration and combustion interface, allowing δ13CH4 analyses to be made on a kilogram of ice.

Contacts – Atmospheric greenhouse gas studies

Ross Martin

Gordon Brailsford

Publications

Related greenhouse gas publications.

Stable Isotopes in Carbonates 

Carbonates are studied using the MAT252 and MAT253 which are equipped with Thermo Scientific Kiel (III & IV) devices, providing automated high-precision determinations of δ13C and δ18O in individual foraminifera and other carbonate samples.

 

NIWA is a leading institute in New Zealand doing high resolution analysis of stable isotopes in carbonates to identify environmental change over timescales of tens to thousands of years. We use these techniques on materials as diverse as foraminfera, shells, fish earbones, and limestone structures in caves. These analyses provide both δ13C and δ18O, with precisions of 0.04‰ and 0.08‰ respectively.

Planktonic foraminifera are single-celled organisms which secrete their tests using oxygen and carbon from the water in which they live. Isotopic analysis on these, and on deepsea corals and brachiopods, tells us much about how the marine climate has changed in the past, including relatively abrupt changes in ocean circulation.

Locked inside speleothems, including stalactites and stalagmites, is a historical record of heavy rain seeping into caves. Isotope analysis here helps define risk assessment models (e.g., for tropical cyclones) and improves understanding of climate changes.

Stable isotopes in coastal fauna such as paua shells provide a picture of local climate variability and help us estimate paua age and growth rate; information vital for assessing the sustainability of these coastal fisheries.

Isotope analysis of fish otoliths (earbones) is clarifying the life histories of some significant commercial species.

These analyses all provide critical information for understanding freshwater, marine, and terrestrial ecosystems, particularly with respect to historical climate change and environment and biology of marine organisms. It is now possible to study past changes in the ocean and climate, provide improved data for climate modelling, and help predict the response of the ocean to climate change. Also to reconstruct seasonal profiles of bygone winters and summers, unravel geographic fish migration patterns and life histories, or even derive daily records of climate for the Miocene (20 Ma).

Contacts – Carbonate Analysis

Dr Andrew Kingston Ph. +64 4 386 0836

Publications

A selected list of publications illustrates NIWA's recent research using a Kiel device, which provides automated high-precision determinations of δ 13C and δ 18O in individual foraminifera and other carbonate samples.

Mass spectrometry-related publications 

Environmental Stable Isotope Analysis

Stable isotope analyses from our Delta Series mass spectrometers and their peripherals (Elemental analyser (EA), Gasbench II, Precon and Thermo Chemical Elemental Analyser (TCEA) have wide-ranging applications in many areas of environmental research.

Elemental analysers linked to Thermo Fisher Scientific DeltaPlus and Delta V Plus mass spectrometers enable us to analyse carbon and nitrogen concentrations and isotope ratios in solid samples from freshwater, marine and terrestrial environments with a focus on ecological studies. In addition, we are able to analyse oxygen and hydrogen in solid and liquid samples using the TCEA, and hydrogen, carbon and nitrogen in water and gas samples on the Gasbench II. This has now widened our scope to include research into hydrologcial, palaoenvironmental and trace gas studies.

The Gasbench II has been optimised to measure: 2H/H in water through equilibration with H2/Pt and 18O/16O in water through equilibration with CO2, with applications relevant to climatic, hydrological, oceanic water mass, ecological and animal movement studies;  18O/16O and 13C/12C in carbonates for palaeoceanographic and climate studies; 13C/12C of dissolved inorganic carbon (DIC) for carbon flux and palaeoclimate research;  and 15N/14N of N2, plus 15N/14N and 18O/16O of N2O for terrestrial, aquatic and atmospheric nitrogen cycle studies. We have also optimized the TCEA for analysis of 2H/H and 18O/16O in solid organics, such as plants, soils, bird material (feathers, claws), tree-ring cellulose and chironomid head capsules (chitin) samples to support research in terrestrial water dynamics, palaeoclimate, climatology, animal migration and ecological studies.

 

Our EA system is optimised to analyse extremely low quantities of nitrogen to down to 2µg N content, enabling the analysis of microscopic samples. In ecological studies, stable isotopes are an extremely useful determinant of the trophic status of organisms and an indicator of their diet. There is a slight variation in C and N stable isotope values between an organism and its food source, which has resulted in the statement "You are what you eat, plus or minus a few per mil". Nitrogen isotopes are the strongest indicators of trophic status, showing a step-wise enrichment in 15N of about 3–4‰ at each successive trophic level. By combining C and N isotopic values of a consumer, it is possible to deduce its likely dietary intake and resolve complex food web structures.

Nitrogen isotope values can be utilised to identify different sources of nitrogen and indicate pollutant pathways. Several natural processes fractionate nitrogen, e.g. inorganic nitrogen assimilation, nitrogen fixation, nitrification, denitrification, ammonification, and other processes of nitrogen metabolism.

A valuable application of stable isotopes is that of tracer or enrichment studies. Such studies enable rates of processes to be directly measured by the incorporation of an artificially-enriched stable isotope. This is an extremely powerful experimental method in environmental studies.

Research Projects

Some examples of specific stable isotope research that NIWA is currently involved in include the following research projects:

Contact – Delta Series Facility

We provide competitive rates for commercial analysis of stable isotope samples and are enthusiastic about research collaboration. For information, including enquiries relating to collaborative research or commercial analyses, contact:

Sarah Bury, Ph. +64 4 386 0347.

Delta Series Publications

A selected list of publications illustrates NIWA’s recent research using the DeltaPlus mass spectrometer.

Mass spectrometry-related publications 

Compound Specific Isotope Analysis (CSIA)

Compound specific stable isotope analysis techniques are an increasingly useful tool to address many ecological and environmental research questions. By analyzing the stable isotope composition of specific compounds, researchers can probe more deeply into the fundamental processes responsible for environmental or ecological change at the molecular level. This results in more refined answers to research questions, that cannot always be effectively addressed with bulk isotope analysis alone.

NIWA specializes in the investigation of oceanic trophic ecology and animal migration using the δ15N values of individual amino acids. More recently, we have developed a method for carbon isotope analysis of fatty acids for tracing sediment sources following the techniques of Gibbs (2008). We are continually developing novel analytical techniques in response to individual research needs, and encourage early contact to discuss potential research opportunities.

CSIA is conducted using gas chromatography isotope ratio mass spectrometry (GC-IRMS). Samples for CSIA are isolated and purified from bulk material (i.e. tissue, feathers, collagen, plant material, etc.) and then derivatized to make them suitable for GC analysis. Following separation of compounds on the GC, samples are combusted in a furnace before gases are introduced into the IRMS. NIWA’s Stable Isotope Analytical Facility houses a Thermo Fisher Scientific (Bremen, Germany) Trace GC Ultra, coupled with a GC-Isolink connected to a Delta V IRMS via a Conflo IV open split. Currently, NIWA offers δ15N and δ13C analysis of amino acids and δ13C analysis of fatty acids (see table at top of page for more info).

Sample processing and derivatization can also be provided by NIWA. Please enquire about your specific sample requirements to the contacts below.

Reference

Gibbs, M. (2008) Identifying source soils in estuarine sediments: a new compound specific isotope method. Estuaries and Coasts, 31, 344-359.

Contacts

Brittany Graham

Andrew Kingston

 

Our stable isotope facility staff specialise in methods developments and novel technological advances. We encourage research collaboration with our colleagues and clients, and aimi to work together as a team to facilitate the best project outcomes. We are happy to provide advice and assistance with projects from conception to publication, and recommend contacting the relevant staff listed in the table below to address research and analytical queries.

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