Oxygen and Carbon Isotopes of Cold-water Corals——Reconstructing Paleotemperature changes and Calcification Mechanism

Mapping Intimacies ◽

10.5194/egusphere-egu2020-6500 ◽

2020 ◽

Author(s):

Le Kong

Keyword(s):

Cold Water ◽

Oxygen And Carbon Isotopes ◽

Ambient Seawater ◽

Coral Skeletons ◽

Geochemical Parameters ◽

Vital Effect ◽

Vital Effects ◽

Geochemical Models ◽

Temperature Proxy ◽

Linear Correlations

&#160; &#160; &#160; &#160; &#160;Cold-water corals represent an intriguing paleoceanographic archive with a great potential to reconstruct high-resolution paleoenvironmental changes. Compared to those of shallow-water corals, proxies derived from cold-water corals have been complicated by biologically mediated vital effects. The oxygen and carbon stable isotope compositions of cold-water coral skeletons are more depleted than the expected carbonate-seawater equilibrium values by ~4&#8211;6&#8240; and ~10&#8240;, respectively. Therefore, it is necessary to correct for the vital effect before using &#948;18O as a temperature proxy. &#948;18O and &#948;13C of cold-water corals exhibit strong linear correlations after adjusting for ambient seawater &#948;18O and &#948;13C values. The &#948;18O intercepts of this linear regression were found to be correlated with water temperatures. This so-called &#8216;intercept method&#8217; can therefore be used to reconstruct temperatures variations of intermediate and deep oceans. Moreover, sampling along the growing bands of cold-water corals can provide samples to generate temperature sequences. After that, three geochemical models have been proposed to explain the &#948;18O and &#948;13C depletion of cold-water corals. However, none of them can explain the behavior of all geochemical parameters. In future, more analyses and experiments at micro-scales are required to adjust these geochemical models or propose new ones.

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Oxygen isotope equilibrium in brachiopod shell fibres in the context of biological control

Mineralogical Magazine ◽

10.1180/minmag.2008.072.1.239 ◽

2008 ◽

Vol 72 (1) ◽

pp. 239-242 ◽

Cited By ~ 1

Author(s):

M. Cusack ◽

A. Pérez-Huerta ◽

P. Chung ◽

D. Parkinson ◽

Y. Dauphin ◽

...

Keyword(s):

Oxygen Isotope ◽

Isotope Composition ◽

Seawater Temperature ◽

Environmental Data ◽

Ambient Seawater ◽

Secondary Layer ◽

Vital Effect ◽

Vital Effects ◽

Stable Oxygen ◽

Isotope Equilibrium

With their long geological history and stable low-Mg calcite shells, Rhynchonelliform brachiopods are attractive sources of environmental data such as past seawater temperature (Buening and Spero, 1996; Auclair et al., 2003; Brand et al., 2003; Parkinson et al., 2005). Concerns about the influence of vital effects on the stable isotope composition of brachiopod shells (Popp et al., 1986), led to isotope analyses of different parts of brachiopod shells in order to identify those parts of the shell that are influenced by any vital effect and those parts that may be suitable recorders of seawater temperature via stable oxygen isotope composition (Carpenter and Lohmann, 1995; Parkinson et al., 2005). Such detailed studies demonstrated that the outer primary layer of acicularcalcite is isotopically light in both δ18O and δ13C while the secondary layer, composed of calcite fibres, is in oxygen-isotope equilibrium with ambient seawater(Fig. 1) (Parkinson et al., 2005).

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pH up-regulation as a potential mechanism for the cold-water coral Lophelia pertusa to sustain growth in aragonite undersaturated conditions

Biogeosciences ◽

10.5194/bg-12-6869-2015 ◽

2015 ◽

Vol 12 (23) ◽

pp. 6869-6880 ◽

Cited By ~ 17

Author(s):

M. Wall ◽

F. Ragazzola ◽

L. C. Foster ◽

A. Form ◽

D. N. Schmidt

Keyword(s):

Deep Water ◽

Cold Water ◽

Isotope Analysis ◽

Lophelia Pertusa ◽

Ambient Seawater ◽

Skeletal Morphology ◽

Composition And Structure ◽

Ph Conditions ◽

Water Ecosystems ◽

Water Coral

Abstract. Cold-water corals are important habitat formers in deep-water ecosystems and at high latitudes. Ocean acidification and the resulting change in aragonite saturation are expected to affect these habitats and impact coral growth. Counter to expectations, the deep water coral Lophelia pertusa has been found to be able to sustain growth even in undersaturated conditions. However, it is important to know whether such undersaturation modifies the skeleton and thus its ecosystem functioning. Here we used Synchrotron X-Ray Tomography and Raman spectroscopy to examine changes in skeleton morphology and fibre orientation. We combined the morphological assessment with boron isotope analysis to determine if changes in growth are related to changes in control of calcification pH. We compared the isotopic composition and structure formed in their natural environment to material grown in culture at lower pH conditions. Skeletal morphology is highly variable but shows no distinctive differences between natural and low pH conditions. Raman investigations found no difference in macromorphological skeletal arrangement of early mineralization zones and secondary thickening between the treatments. The δ11B analyses show that L. pertusa up-regulates the internal calcifying fluid pH (pHcf) during calcification compared to ambient seawater pH and maintains a similar elevated pHcf at increased pCO2 conditions. We suggest that as long as the energy is available to sustain the up-regulation, i.e. individuals are well fed, there is no detrimental effect to the skeletal morphology.

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Relationship between δ18O and minor element composition of Terebratalia transversa

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s1755691008075671 ◽

2007 ◽

Vol 98 (3-4) ◽

pp. 443-449 ◽

Cited By ~ 3

Author(s):

Maggie Cusack ◽

David Parkinson ◽

Alberto Pérez-Huerta ◽

Jennifer England ◽

Gordon B. Curry ◽

...

Keyword(s):

Oxygen Isotope ◽

Isotope Composition ◽

Seawater Temperature ◽

Minor Element ◽

Oxygen Isotope Composition ◽

Secondary Layer ◽

Vital Effects ◽

Stable Oxygen ◽

Temperature Proxy ◽

Isotope Equilibrium

ABSTRACTWith their extensive fossil record and shells of stable low-Mg calcite, rhynchonelliform brachiopods are attractive sources of climate information via seawater temperature proxies such as stable oxygen isotope composition. In Terebratalia transversa (Sowerby) there is a progression towards oxygen isotope equilibrium in the calcite of the innermost secondary layer. This study confirms the lack of any vital effects influencing oxygen isotope composition of T. transversa, even in specialised areas of the innermost secondary layer. Calcite Mg/Ca ratio is another potential seawater temperature proxy, that has the advantage of not being influenced by salinity. Mg concentrations measured by electron microprobe analyses indicate that there is no concomitant decrease in Mg concentration towards the inner secondary layer, associated with the progressive shift towards oxygen isotope equilibrium. Mg distribution is heterogeneous throughout the shell and correlates with that of sulphur, which may be a proxy for organic components, suggesting that some of the Mg may not be in the calcite lattice. It is essential therefore, to determine the chemical environment of the magnesium ions to avoid any erroneous temperature extrapolations in brachiopods or any other calcite biomineral.

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Vanishing coccolith vital effects with alleviated CO2 limitation

Biogeosciences Discussions ◽

10.5194/bgd-12-15835-2015 ◽

2015 ◽

Vol 12 (18) ◽

pp. 15835-15866 ◽

Cited By ~ 1

Author(s):

M. Hermoso ◽

I. Z. X. Chan ◽

H. L. O. McClelland ◽

A. M. C. Heureux ◽

R. E. M. Rickaby

Keyword(s):

Inorganic Carbon ◽

Dissolved Inorganic Carbon ◽

Calcareous Nannofossils ◽

Carbon And Oxygen Isotopes ◽

Carbon Availability ◽

Vital Effect ◽

Vital Effects ◽

Multiple Species ◽

Atmospheric Co2 Concentrations

Abstract. By recreating a range of geologically relevant concentrations of dissolved inorganic carbon (DIC) in the laboratory, we demonstrate that the magnitude of the vital effects in both carbon and oxygen isotopes of coccolith calcite of multiple species relates to ambient DIC concentration. Under high DIC levels, all the examined coccoliths lacked any offset from inorganic calcite, whereas in low (present-day) DIC concentrations, these vital effects and interspecies differences become substantial. These laboratory observations support the recent hypothesis from field observations that the appearance of interspecific vital effect in coccolithophores coincides with the long-term Neogene decline of atmospheric CO2 concentrations. The present study brings further valuable constraints on coccolith isotopic compositions by demonstrating the threshold for the absence of vital effects under high DIC regimes. From a mechanistic viewpoint, we show that the vital effect is determined by physiology; growth rate, cell size and relative rates of photosynthesis and calcification, and a modulation of these parameters with ambient carbon availability. This study provides palaeoceanographers with a biogeochemical framework that can be utilised to further develop the use of calcareous nannofossils in palaeoceanography to derive sea surface temperature and pCO2 levels.

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Faculty Opinions recommendation of A biological origin for climate signals in corals—Trace element “vital effects” are ubiquitous in Scleractinian coral skeletons.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1046293.496231 ◽

2006 ◽

Author(s):

Doug Wallace

Keyword(s):

Trace Element ◽

Scleractinian Coral ◽

Biological Origin ◽

Coral Skeletons ◽

Vital Effects ◽

Climate Signals

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Crystallographic contribution to the vital effect in biogenic carbonates Mg/Ca thermometry

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s1755691011010036 ◽

2011 ◽

Vol 102 (1) ◽

pp. 35-41 ◽

Cited By ~ 4

Author(s):

Alberto Pérez-Huerta ◽

Maggie Cusack ◽

Paul Dalbeck

Keyword(s):

Seawater Temperature ◽

Environmental Parameters ◽

Magnesium Concentration ◽

Chemical Information ◽

Environmental Signals ◽

Physico Chemical ◽

Vital Effect ◽

Vital Effects ◽

Biogenic Carbonates ◽

Insufficient Knowledge

ABSTRACTThe processes involved in vital effects, defined as biological processes overriding environmental signals, are not well understood and this hampers the interpretation of environmental parameters such as seawater temperature. Insufficient knowledge is available about changes in physico-chemical parameters, in particular those related to crystallography, associated with biomineral formation and emplacement. This paper assesses the influence of crystallography on Mg2+ concentration and distribution in calcite biominerals of bivalved marine organisms, mussels and rhynchonelliform brachiopods, and considers the implications for Mg/Ca thermometry. In the mussel Mytilus edulis, changes in Mg2+ are not associated with crystallography; but in the brachiopod Terebratulina retusa, increases in Mg2+ concentrations (∼0·5–0·6 wt. ) are associated with the {0001 planes of calcite biominerals. A comparison between mussels and brachiopods with avian eggshells, which form at constant ambient temperature, also reveals that there is at least a common 0·1 wt. variation in magnesium concentration in these calcite biomineral systems unrelated to temperature or crystallography. Results demonstrate that the integration of contextual crystallographic, biological and chemical information may be important to extract accurate environmental information from biominerals.

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