scholarly journals δ<sup>18</sup>O water isotope in the <i>i</i>LOVECLIM model (version 1.0) – Part 3: A palaeo-perspective based on present-day data–model comparison for oxygen stable isotopes in carbonates

2013 ◽  
Vol 6 (5) ◽  
pp. 1505-1516 ◽  
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.

scholarly journals δ<sup>18</sup>O water isotope in the <i>i</i>LOVECLIM model (version 1.0) – Part 3: A paleoperspective based on present-day data-model comparison for oxygen stable isotopes in carbonates

2013 ◽  
Vol 6 (1) ◽  
pp. 1527-1558
Author(s):  
T. Caley ◽  
D. M. Roche
Keyword(s):  
Stable Isotopes ◽  
Data Model ◽  
Model Comparison ◽  
Oceanic Circulation ◽  
Three Dimensional Model ◽  
Secondary Importance ◽  
Surface Ocean ◽  
The Past ◽  
Oxygen Stable Isotopes ◽  
Comparison Exercise

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 (&amp;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.

scholarly journals Quantifying the effect of seasonal and vertical habitat tracking on planktonic foraminifera proxies

2017 ◽  
Vol 13 (6) ◽  
pp. 573-586 ◽  
Author(s):  
Lukas Jonkers ◽  
Michal Kučera
Keyword(s):  
Environmental Change ◽  
Data Model ◽  
Model Comparison ◽  
Planktonic Foraminifera ◽  
Temporal Trends ◽  
Global Scale ◽  
Individual Species ◽  
Near Surface ◽  
Proxy Records ◽  
Habitat Tracking

Abstract. The composition of planktonic foraminiferal (PF) calcite is routinely used to reconstruct climate variability. However, PF ecology leaves a large imprint on the proxy signal: seasonal and vertical habitats of PF species vary spatially, causing variable offsets from annual mean surface conditions recorded by sedimentary assemblages. PF seasonality changes with temperature in a way that minimises the environmental change that individual species experience and it is not unlikely that changes in depth habitat also result from such habitat tracking. While this behaviour could lead to an underestimation of spatial or temporal trends as well as of variability in proxy records, most palaeoceanographic studies are (implicitly) based on the assumption of a constant habitat. Up to now, the effect of habitat tracking on foraminifera proxy records has not yet been formally quantified on a global scale. Here we attempt to characterise this effect on the amplitude of environmental change recorded in sedimentary PF using core top δ18O data from six species. We find that the offset from mean annual near-surface δ18O values varies with temperature, with PF δ18O indicating warmer than mean conditions in colder waters (on average by −0.1 ‰ (equivalent to 0.4 °C) per °C), thus providing a first-order quantification of the degree of underestimation due to habitat tracking. We use an empirical model to estimate the contribution of seasonality to the observed difference between PF and annual mean δ18O and use the residual Δδ18O to assess trends in calcification depth. Our analysis indicates that given an observation-based model parametrisation calcification depth increases with temperature in all species and sensitivity analysis suggests that a temperature-related seasonal habitat adjustment is essential to explain the observed isotope signal. Habitat tracking can thus lead to a significant reduction in the amplitude of recorded environmental change. However, we show that this behaviour is predictable. This allows accounting for habitat tracking, enabling more meaningful reconstructions and improved data–model comparison.

scholarly journals Paleoclimate Data–Model Comparison and the Role of Climate Forcings over the Past 1500 Years*

2013 ◽  
Vol 26 (18) ◽  
pp. 6915-6936 ◽  
Author(s):  
Steven J. Phipps ◽  
Helen V. McGregor ◽  
Joëlle Gergis ◽  
Ailie J. E. Gallant ◽  
Raphael Neukom ◽  
...  
Keyword(s):  
Case Studies ◽  
Data Model ◽  
Model Comparison ◽  
Climate System ◽  
Central Pacific ◽  
Model Simulations ◽  
The Past ◽  
Paleoclimate Data ◽  
Anthropogenic Forcings

Abstract The past 1500 years provide a valuable opportunity to study the response of the climate system to external forcings. However, the integration of paleoclimate proxies with climate modeling is critical to improving the understanding of climate dynamics. In this paper, a climate system model and proxy records are therefore used to study the role of natural and anthropogenic forcings in driving the global climate. The inverse and forward approaches to paleoclimate data–model comparison are applied, and sources of uncertainty are identified and discussed. In the first of two case studies, the climate model simulations are compared with multiproxy temperature reconstructions. Robust solar and volcanic signals are detected in Southern Hemisphere temperatures, with a possible volcanic signal detected in the Northern Hemisphere. The anthropogenic signal dominates during the industrial period. It is also found that seasonal and geographical biases may cause multiproxy reconstructions to overestimate the magnitude of the long-term preindustrial cooling trend. In the second case study, the model simulations are compared with a coral δ18O record from the central Pacific Ocean. It is found that greenhouse gases, solar irradiance, and volcanic eruptions all influence the mean state of the central Pacific, but there is no evidence that natural or anthropogenic forcings have any systematic impact on El Niño–Southern Oscillation. The proxy climate relationship is found to change over time, challenging the assumption of stationarity that underlies the interpretation of paleoclimate proxies. These case studies demonstrate the value of paleoclimate data–model comparison but also highlight the limitations of current techniques and demonstrate the need to develop alternative approaches.

scholarly journals Diving into the Past: A Paleo Data–Model Comparison Workshop on the Late Glacial and Holocene

2019 ◽  
Vol 100 (1) ◽  
pp. ES1-ES4 ◽  
Author(s):  
Nils Weitzel ◽  
Sebastian Wagner ◽  
Jesper Sjolte ◽  
Marlene Klockmann ◽  
Oliver Bothe ◽  
...  
Keyword(s):  
Data Model ◽  
Model Comparison ◽  
Late Glacial ◽  
The Past ◽  
Late Glacial And Holocene

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

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.

LBA-ECO CD-02 CARBON, NITROGEN, OXYGEN STABLE ISOTOPES IN ORGANIC MATERIAL, BRAZIL

2010 ◽  
Author(s):  
J. BERRY, ◽  
C. COOK, ◽  
T.F. DOMINGUES, ◽  
J. EHLERINGER, ◽  
L. FLANAGAN, ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Organic Material ◽  
Oxygen Stable Isotopes

A Qualified Assertion Database for the History of Places

2019 ◽  
Vol 13 (1-2) ◽  
pp. 95-115
Author(s):  
Brandon Plewe
Keyword(s):  
Data Model ◽  
Temporal Change ◽  
Religious Congregations ◽  
Historical Gis ◽  
The Past ◽  
Model Based ◽  
Complex Information ◽  
Invaluable Tool ◽  
History Of ◽  
The Rich

Historical place databases can be an invaluable tool for capturing the rich meaning of past places. However, this richness presents obstacles to success: the daunting need to simultaneously represent complex information such as temporal change, uncertainty, relationships, and thorough sourcing has been an obstacle to historical GIS in the past. The Qualified Assertion Model developed in this paper can represent a variety of historical complexities using a single, simple, flexible data model based on a) documenting assertions of the past world rather than claiming to know the exact truth, and b) qualifying the scope, provenance, quality, and syntactics of those assertions. This model was successfully implemented in a production-strength historical gazetteer of religious congregations, demonstrating its effectiveness and some challenges.

scholarly journals The first 10 years of the international coordination network for standards in systems and synthetic biology (COMBINE)

2020 ◽  
Vol 17 (2-3) ◽  
Author(s):  
Dagmar Waltemath ◽  
Martin Golebiewski ◽  
Michael L Blinov ◽  
Padraig Gleeson ◽  
Henning Hermjakob ◽  
...  
Keyword(s):  
Synthetic Biology ◽  
Data Model ◽  
Computational Models ◽  
Life Sciences ◽  
The Past ◽  
Challenges And Opportunities ◽  
Stakeholder Workshop ◽  
Software Engineers ◽  
Future Work ◽  
Modeling In Biology

AbstractThis paper presents a report on outcomes of the 10th Computational Modeling in Biology Network (COMBINE) meeting that was held in Heidelberg, Germany, in July of 2019. The annual event brings together researchers, biocurators and software engineers to present recent results and discuss future work in the area of standards for systems and synthetic biology. The COMBINE initiative coordinates the development of various community standards and formats for computational models in the life sciences. Over the past 10 years, COMBINE has brought together standard communities that have further developed and harmonized their standards for better interoperability of models and data. COMBINE 2019 was co-located with a stakeholder workshop of the European EU-STANDS4PM initiative that aims at harmonized data and model standardization for in silico models in the field of personalized medicine, as well as with the FAIRDOM PALs meeting to discuss findable, accessible, interoperable and reusable (FAIR) data sharing. This report briefly describes the work discussed in invited and contributed talks as well as during breakout sessions. It also highlights recent advancements in data, model, and annotation standardization efforts. Finally, this report concludes with some challenges and opportunities that this community will face during the next 10 years.

scholarly journals Tree Vitality and Forest Health: Can Tree-Ring Stable Isotopes Be Used as Indicators?

2021 ◽  
Author(s):  
Paolo Cherubini ◽  
Giovanna Battipaglia ◽  
John L. Innes
Keyword(s):  
Air Pollution ◽  
Stable Isotopes ◽  
Tree Ring ◽  
Forest Decline ◽  
Forest Health ◽  
Stress Factors ◽  
Tree Vitality ◽  
The Past ◽  
Physiological Processes

Abstract Purpose of Review Society is concerned about the long-term condition of the forests. Although a clear definition of forest health is still missing, to evaluate forest health, monitoring efforts in the past 40 years have concentrated on the assessment of tree vitality, trying to estimate tree photosynthesis rates and productivity. Used in monitoring forest decline in Central Europe since the 1980s, crown foliage transparency has been commonly believed to be the best indicator of tree condition in relation to air pollution, although annual variations appear more closely related to water stress. Although crown transparency is not a good indicator of tree photosynthesis rates, defoliation is still one of the most used indicators of tree vitality. Tree rings have been often used as indicators of past productivity. However, long-term tree growth trends are difficult to interpret because of sampling bias, and ring width patterns do not provide any information about tree physiological processes. Recent Findings In the past two decades, tree-ring stable isotopes have been used not only to reconstruct the impact of past climatic events, such as drought, but also in the study of forest decline induced by air pollution episodes, and other natural disturbances and environmental stress, such as pest outbreaks and wildfires. They have proven to be useful tools for understanding physiological processes and tree response to such stress factors. Summary Tree-ring stable isotopes integrate crown transpiration rates and photosynthesis rates and may enhance our understanding of tree vitality. They are promising indicators of tree vitality. We call for the use of tree-ring stable isotopes in future monitoring programmes.

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