Variability of surface ocean radiocarbon and stable isotopes in the southwestern Pacific

Abstract. Oxygen stable isotopes (18O) are among the most usual tools in paleoclimatology/paleoceanography. Simulation of oxygen stable isotopes allows testing how the past variability of these isotopes in water can be interpreted. By modelling the proxy directly in the model, the results can also be directly compared with the data. Water isotopes have been implemented in the global three-dimensional model of intermediate complexity iLOVECLIM allowing fully coupled atmosphere-ocean simulations. In this study, we present the validation of the model results for present day climate against global database for oxygen stable isotopes in carbonates. The limitation of the model together with the processes operating in the natural environment reveal the complexity of use the continental calcite 18O signal of speleothems for a data-model comparison exercise. On the contrary, the reconstructed surface ocean calcite δ18O signal in iLOVECLIM does show a very good agreement with late Holocene database (foraminifers) at the global and regional scales. Our results indicate that temperature and the isotopic composition of the seawater are the main control on the fossil δ18O signal recorded in foraminifer shells and that depth habitat and seasonality play a role but have secondary importance. We argue that a data-model comparison for surface ocean calcite δ18O in past climate, such as the last glacial maximum (&approx;21 000 yr), could constitute an interesting tool for mapping the potential shifts of the frontal systems and circulation changes throughout time. Similarly, the potential changes in intermediate oceanic circulation systems in the past could be documented by a data (benthic foraminifers)-model comparison exercise whereas future investigations are necessary in order to quantitatively compare the results with data for the deep ocean.

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δ18O water isotope in the iLOVECLIM model (version 1.0) – Part 3: A palaeo-perspective based on present-day data–model comparison for oxygen stable isotopes in carbonates

Geoscientific Model Development ◽

10.5194/gmd-6-1505-2013 ◽

2013 ◽

Vol 6 (5) ◽

pp. 1505-1516 ◽

Cited By ~ 19

Author(s):

T. Caley ◽

D. M. Roche

Keyword(s):

Stable Isotopes ◽

Data Model ◽

Model Comparison ◽

Individual Species ◽

Oceanic Circulation ◽

Three Dimensional Model ◽

Surface Ocean ◽

The Past ◽

Oxygen Stable Isotopes ◽

Comparison Exercise

Abstract. Oxygen stable isotopes (δ18O) are among the most useful tools in palaeoclimatology/palaeoceanography. Simulation of oxygen stable isotopes allows testing how the past variability of these isotopes in water can be interpreted. By modelling the proxy directly in the model, the results can also be directly compared with the data. Water isotopes have been implemented in the global three-dimensional model of intermediate complexity iLOVECLIM, allowing fully coupled atmosphere–ocean simulations. In this study, we present the validation of the model results for present-day climate against the global database for oxygen stable isotopes in carbonates. The limitation of the model together with the processes operating in the natural environment reveal the complexity of use the continental calcite-δ18O signal of speleothems for a global quantitative data–model comparison exercise. On the contrary, the reconstructed surface ocean calcite-δ18O signal in iLOVECLIM does show a very good agreement with the late Holocene database (foraminifers) at the global and regional scales. Our results indicate that temperature and the isotopic composition of the seawater are the main control on the fossil-δ18O signal recorded in foraminifer shells when all species are grouped together. Depth habitat, seasonality and other ecological effects play a more significant role when individual species are considered. We argue that a data–model comparison for surface ocean calcite δ18O in past climates, such as the Last Glacial Maximum (≈ 21 000 yr), could constitute an interesting tool for mapping the potential shifts of the frontal systems and circulation changes throughout time. Similarly, the potential changes in intermediate oceanic circulation systems in the past could be documented by a data (benthic foraminifers)-model comparison exercise whereas future investigations are necessary in order to quantitatively compare the results with data for the deep ocean.

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Using stable isotopes to distinguish atmospheric nitrate production and its contribution to the surface ocean across hemispheres

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2021.116914 ◽

2021 ◽

Vol 564 ◽

pp. 116914

Author(s):

Guitao Shi ◽

Hongmei Ma ◽

Zhuoyi Zhu ◽

Zhengyi Hu ◽

Zhenlou Chen ◽

...

Keyword(s):

Stable Isotopes ◽

Surface Ocean ◽

Nitrate Production ◽

Atmospheric Nitrate

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A stage 7 marine interglacial record (the Gr deland Interglacial) on J ren, southwestern Norway; foraminiferal, stable isotopes and amino acid evidence

Boreas ◽

10.1080/030094899750044396 ◽

1999 ◽

Vol 28 (2) ◽

pp. 326-346

Author(s):

Hans Petter Sejrup, Marianne Iversen, Ei

Keyword(s):

Stable Isotopes ◽

Amino Acid

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Interannual variation of stable isotopes in Antarctic precipitation in response to El Niño-Southern Oscillation

Geophysical Research Letters ◽

10.1029/2000gl012815 ◽

2002 ◽

Vol 29 (1) ◽

Cited By ~ 10

Author(s):

Kimpei Ichiyanagi

Keyword(s):

Stable Isotopes ◽

El Niño ◽

Interannual Variation ◽

El Nino ◽

Southern Oscillation ◽

El Niño Southern Oscillation ◽

El Nino Southern Oscillation ◽

Antarctic Precipitation

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Disentangling the role of shared ancestry and the environment on leaf stable isotopes

10.32942/osf.io/mfhve ◽

2019 ◽

Author(s):

Marko J. Spasojevic ◽

Sören Weber1

Keyword(s):

Stable Isotopes ◽

Environmental Conditions ◽

Evolutionary History ◽

Environmental Control ◽

Phylogenetic Signal ◽

Individual Species ◽

Habitat Types ◽

Δ13c And Δ15n ◽

Environmental Controls ◽

Shared Ancestry

Stable carbon (C) and nitrogen (N) isotopes in plants are important indicators of plant water use efficiency and N acquisition strategies. While often regarded as being under environmental control, there is growing evidence that evolutionary history may also shape variation in stable isotope ratios (δ13C and δ15N) among plant species. Here we examined patterns of foliar δ13C and δ15N in alpine tundra for 59 species in 20 plant families. To assess the importance of environmental controls and evolutionary history, we examined if average δ13C and δ15N predictably differed among habitat types, if individual species exhibited intraspecific trait variation (ITV) in δ13C and δ15N, and if there were a significant phylogenetic signal in δ13C and δ15N. We found that variation among habitat types in both δ13C and δ15N mirrored well-known patterns of water and nitrogen limitation. Conversely, we also found that 40% of species exhibited no ITV in δ13C and 35% of species exhibited no ITV in δ15N, suggesting that some species are under stronger evolutionary control. However, we only found a modest signal of phylogenetic conservatism in δ13C and no phylogenetic signal in δ15N suggesting that shared ancestry is a weaker driver of tundra wide variation in stable isotopes. Together, our results suggest that both evolutionary history and local environmental conditions play a role in determining variation in δ13C and δ15N and that considering both factors can help with interpreting isotope patterns in nature and with predicting which species may be able to respond to rapidly changing environmental conditions.

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