Kirsty Crocket

Kirsty Crocket
Dounreay

BSc (Hons), MSc, PhD

About

28
Publications
3,512
Reads
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550
Citations
Citations since 2017
9 Research Items
379 Citations
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080
Additional affiliations
June 2018 - November 2020
The University of Edinburgh
Position
  • Science Coordinator
February 2018 - May 2018
University of St Andrews
Position
  • Science Coordinator
Description
  • The Changing Arctic Ocean is a 5-year, flagship research programme (2017-2022), investigating the impacts of climate change on the large-scale ecosystem structure and biogeochemical functioning of the Arctic Ocean. https://www.changing-arctic-ocean.ac.uk/
August 2013 - January 2018
Scottish Association for Marine Science
Position
  • Lecturer
Description
  • Lecturer and module leader on 4th year Palaeoceanography and 3rd year Literature Review; Lecturer and marker on 4th year Polar Seas, 2nd year Chemical Oceanography, and 2nd year Marine Geology.
Education
September 2004 - September 2005
University of Leeds
Field of study
  • Geochemistry (distinction)

Publications

Publications (28)
Article
Understanding the history of continental ice-sheet growth on North America, and in particular that of the Laurentide Ice Sheet (LIS), is important for palaeoclimate and sea-level reconstructions. Information on ice-sheet extent pre-dating the Last Glacial Maximum (LGM) is heavily reliant, though, on the outputs of numerical models underpinned by sc...
Article
Significance Southern Ocean circulation is a central aspect of the climate system influenced by the overlying Southern Hemisphere westerly winds (SWW) and surface buoyancy forcing. Yet, the response of Southern Ocean water mass mixing to SWW changes is largely unconstrained for the Holocene (the last ∼11,700 y). We extracted the fingerprint of ocea...
Article
Chemical weathering of silicate rock is one of the major long-term sinks of atmospheric CO 2. While several radiogenic isotope systems (e.g. Nd, Pb, Os) in the authigenic component of marine sediments show temporal patterns that could be interpreted in terms of fluctuations in chemical weathering rate over glacial cycles, recent work using berylliu...
Presentation
Chemical weathering of silicate rocks is one of the major long-term sinks of atmospheric CO2. Any change in the rate of this process as a function of climate has important implications for climate sensitivity. While several radiogenic isotope systems (e.g. Nd, Pb, Os) in the authigenic component of recent marine sediments show temporal patterns tha...
Article
Full-text available
Seawater rare earth element (REE) concentrations are increasingly applied to reconstruct water mass histories by exploiting relative changes in the distinctive normalised patterns. However, the mechanisms by which water masses gain their patterns are yet to be fully explained. To examine this, we collected water samples along the Extended Ellett Li...
Article
The reconstruction of past ice sheet dynamics can inform on long-term ice stream activity, and in turn provide constraints on the response of modern ice sheets to climate change. The Hebrides Ice Stream (HIS) flowed across part of the western Scottish shelf to the shelf-break during the last glacial cycle. To investigate the deglacial dynamics of t...
Article
Full-text available
Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorporated into their skeletons. We here present new r...
Conference Paper
Full-text available
Seawater rare earth element (REE) data are increasingly applied to reconstruct water mass histories by exploiting relative changes in the distinctive normalised pattern of dissolved seawater REE concentrations. However, the mechanisms by which water masses gain their seawater REE patterns have yet to be fully explained. To address this, we collecte...
Conference Paper
Full-text available
The biogeochemical iron cycle exerts significant control on the carbon cycle 1. Iron is a limiting nutrient in large areas of the world's oceans and its bioavailability controls CO 2 uptake by marine photosynthesizing microorganisms. While atmospheric iron inputs to the open ocean have been extensively measured, global river inputs have likely been...
Article
Isotopes of the actinide elements protactinium (Pa), thorium (Th), and uranium (U), and the lanthanide element neodymium (Nd) are often used as complementary tracers of modern and past oceanic processes. The extraction of such elements from low abundance matrices, such as seawater and carbonate, is however labor-intensive and requires significant a...
Article
Full-text available
The neodymium (Nd) isotopic composition of seawater is commonly used as a proxy to study past changes in the thermohaline circulation. The modern database for such reconstructions is however poor and the understanding of the underlying processes is incomplete. Here we present new observational data for Nd isotopes and concentrations from twelve sea...
Article
The last deglaciation was characterised by a series of millennial scale climate events that have been linked to deep ocean variability. While often implied in interpretations, few direct constraints exist on circulation changes at mid-depths. Here we provide new constraints on the variability of deglacial mid-depth circulation using combined radioc...
Article
An important issue with fossil corals concerns their apparently higher Nd concentrations compared to modern counterparts (~ 7–310 ppb vs. ~ 3–51 ppb respectively). Variable to high Nd concentrations could arise for a number of reasons, but here we focus solely on evaluating the effectiveness of coral cleaning to remove external, Nd-rich encrustatio...
Article
Ice sheet-ocean interactions are both a response to climate forcing and a source of climate feedback, releasing freshwater to the surface ocean and influencing climate and atmospheric CO2 through changes in ocean circulation. Documenting the outcomes of these interactions for recent glacial cycles is important given current and future scenarios of...
Article
One of the key activities during the initial phase of the international GEOTRACES program was an extensive international intercalibration effort, to ensure that results for a range of trace elements and isotopes (TEIs) from different cruises and from different laboratories can be compared in a meaningful way. Here we present the results from the in...
Article
Full-text available
One of the key activities during the initial phase of the international GEOTRACES program was an extensive international intercalibration effort, to ensure that results for a range of trace elements and isotopes (TEIs) from different cruises and from different laboratories can be compared in a meaningful way. Here we present the results from the in...
Article
Full-text available
ISI Document Delivery No.: 956AU Times Cited: 14 Cited Reference Count: 45 Cited References: Alibo DS, 1999, GEOCHIM COSMOCHIM AC, V63, P363, DOI 10.1016/S0016-7037(98)00279-8 Bishop J., METHODS IN PRESS Bishop JKB, 2008, DEEP-SEA RES PT I, V55, P1684, DOI 10.1016/j.dsr.2008.07.012 Chu ZY, 2009, J ANAL ATOM SPECTROM, V24, P1534, DOI 10.1039/b904047...
Data
Regional weathering intensity must have changed dramatically at high latitudes during the Quaternary as a consequence of repeated continental glaciation. Investigation of these glacial/interglacial changes at high temporal resolution is possible with the recent development of Pb isotopes in FeMn oxyhydroxide phases as a proxy for region-specific we...
Article
Full-text available
North Atlantic climate is very sensitive to overturning in the Greenland-Iceland-Norwegian (GIN) Seas, overflow of deep water into the North Atlantic via the Greenland-Iceland-Scotland Ridge, and compensating northward flow of warm surface water. Physical models suggest that, in the absence of such overturning, oceanic heat transport to the Norther...

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Projects

Projects (2)
Project
The biogeochemical iron cycle exerts significant control on the carbon cycle. Iron is a limiting nutrient in large areas of the world’s oceans and its bioavailability controls CO₂ uptake by marine photosynthesizing microorganisms¹. In their review of the iron cycle, Raiswell and Canfield (2012) highlight the importance of resolving the nature and composition of Fe colloids and nanoparticulates in the dissolved fraction in order to improve understanding of their role in biogeochemical cycles. The project explores the development of methods to facilitate the investigation of the submicron particulate Fe fraction. This fraction is very dilute in seawater, and is often classed within the “dissolved” fraction as it is smaller than the conventional 0.45 µm cut-off. The small colloids and nanoparticles¹ in this submicron fraction are well suited to characterisation by Mössbauer spectroscopy, specifically the speciation, mineralogy and morphology of iron particles. Conventional Mössbauer spectroscopy requires concentration of ~10 mg/cm² of Fe on a minimum area of ~1 cm2. In coastal waters, where the “dissolved” Fe fraction is very dilute, achieving this is simply not practicable and can be coupled with lengthy measurement times². We can address these limitations by using synchrotron-based Mössbauer-related applications at the European Synchrotron Radiation Facility, Grenoble, which require a reduced sample amount compared to conventional Mössbauer spectroscopy³. The 57Fe Synchrotron Mössbauer Source (SMS) uses a micron-sized diameter beam and high luminosity, allowing investigation of microscopic samples with a high data quality output in significantly reduced measurement times². Before applying for beamtime at the ESRF, we need to develop a method to isolate the submicron colloidal fraction of Fe-bearing particles and concentrate it in a small volume, optimum for Mössbauer spectroscopy. An initial sampling campaign was carried out in Loch Etive and its main tributaries. We filtered 2 L water samples through a 0.45 µm filter membrane, followed by tangential flow filtration (100 kDa), and the resultant retentate was freeze dried. Measurement by ICP-MS of Fe concentrations in the dissolved (<0.4 μm) and “truly” dissolved (<5 kDa) fractions supports the low Fe concentrations in the colloidal fraction, demonstrating the need for increased sample volumes. Therefore, development of these concentration techniques will be achieved using river waters known to be iron rich. The poster will explore these methods and investigate the anticipated challenges of their further development for higher salinity waters. Acknowledgements: This is a MASTS-funded PhD project (GSS30). Preliminary work was supported by a SAGES PECRE grant to C.S., and a MASTS Visiting Fellowship award (VF41) to K.C. Thank you to Dr David Green, SAMS, Scottish Marine Institute, for his invaluable help and use of the tangential flow filtration unit. References: 1. Raiswell and Canfield (2012) The Iron Biogeochemical Cycle Past and Present. Geochemical Perspectives, 1(1), 1-220. 2. Schröder et al. (2016) The biogeochemical iron cycle and astrobiology. Hyperfine Interactions, 237, 85. 3. Potapkin et al. (2012) The ⁵⁷Fe Synchrotron Mössbauer Source at the ESRF. J. Synchrotron Rad., 19, 559-569.