scholarly journals Seawater pH reconstruction using boron isotopes in multiple planktonic foraminifera species with different depth habitats and their potential to constrain pH and pCO<sub>2</sub> gradients

2019 ◽  
Author(s):  
Maxence Guillermic ◽  
Sambuddha Misra ◽  
Robert Eagle ◽  
Alexandra Villa ◽  
Fengming Chang ◽  
...  
Keyword(s):  
Sediment Core ◽  
Planktonic Foraminifera ◽  
Boron Isotope ◽  
Small Samples ◽  
Light Limitation ◽  
Ph Gradients ◽  
Past Behavior ◽  
Seawater Ph ◽  
Neogloboquadrina Dutertrei ◽  
Carbon Pump

Abstract. Boron isotope systematics of planktonic foraminifera from core-top sediments and culture experiments have been studied to investigate the sensitivity of δ11B of their calcite tests to seawater pH. However, our knowledge of the relationship between δ11B and pH remains incomplete for several taxa. Thus, to expand the potential scope of application of this proxy, we report data for 7 different species of planktonic foraminifera from sediment core-tops. We utilize a method for the measurement of small samples of foraminifera and calculate the δ11B-calcite sensitivity to pH for Globigerinoides ruber, Trilobus sacculifer (sacc or w/o sacc), Orbulina universa, Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globorotalia menardii and Globorotalia tumida, including for unstudied coretops and species. The sensitivity of δ11Bcarbonate to δ11Bborate (eg. Δδ11Bcarbonate/Δδ11Bborate) in core-tops is close to unity. Deep-dwelling species closely follow the core-top calibration for O. universa, which is attributed to respiration-driven microenvironments, likely caused by light limitation for symbiont-bearing foraminifera. These taxa have diverse ecological preferences and are from sites that span a range of oceanographic regimes, including some that are in regions of air-sea equilibrium and others that are out of equilibrium with the atmosphere. Our data support the premise that utilizing boron isotope measurements of multiple species within a sediment core can be utilized to constrain vertical profiles of pH and pCO2 at sites spanning different oceanic regimes, thereby constraining changes in vertical pH gradients and yielding insights into the past behavior of the oceanic carbon pump.

scholarly journals Seawater pH reconstruction using boron isotopes in multiple planktonic foraminifera species with different depth habitats and their potential to constrain pH and <i>p</i>CO<sub>2</sub> gradients

2020 ◽  
Vol 17 (13) ◽  
pp. 3487-3510 ◽  
Author(s):  
Maxence Guillermic ◽  
Sambuddha Misra ◽  
Robert Eagle ◽  
Alexandra Villa ◽  
Fengming Chang ◽  
...  
Keyword(s):  
Sediment Core ◽  
Planktonic Foraminifera ◽  
Boron Isotope ◽  
Small Samples ◽  
Light Limitation ◽  
Ph Gradients ◽  
Past Behavior ◽  
Seawater Ph ◽  
Neogloboquadrina Dutertrei ◽  
Multiple Species

Abstract. Boron isotope systematics of planktonic foraminifera from core-top sediments and culture experiments have been studied to investigate the sensitivity of δ11B of calcite tests to seawater pH. However, our knowledge of the relationship between δ11B and pH remains incomplete for many taxa. Thus, to expand the potential scope of application of this proxy, we report δ11B data for seven different species of planktonic foraminifera from sediment core tops. We utilize a method for the measurement of small samples of foraminifera and calculate the δ11B-calcite sensitivity to pH for Globigerinoides ruber, Trilobus sacculifer (sacc or without sacc), Orbulina universa, Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globorotalia menardii, and Globorotalia tumida, including for unstudied core tops and species. These taxa have diverse ecological preferences and are from sites that span a range of oceanographic regimes, including some that are in regions of air–sea equilibrium and others that are out of equilibrium with the atmosphere. The sensitivity of δ11Bcarbonate to δ11Bborate (e.g., Δδ11Bcarbonate∕Δδ11Bborate) in core tops is consistent with previous studies for T. sacculifer and G. ruber and close to unity for N. dutertrei, O. universa, and combined deep-dwelling species. Deep-dwelling species closely follow the core-top calibration for O. universa, which is attributed to respiration-driven microenvironments likely caused by light limitation and/or symbiont–host interactions. Our data support the premise that utilizing boron isotope measurements of multiple species within a sediment core can be utilized to constrain vertical profiles of pH and pCO2 at sites spanning different oceanic regimes, thereby constraining changes in vertical pH gradients and yielding insights into the past behavior of the oceanic carbon pumps.

scholarly journals PRELIMINARY STUDIES ON SEDIMENT CORE FROM THE TYRO BASIN

2017 ◽  
Vol 50 (1) ◽  
pp. 324
Author(s):  
M. Geraga ◽  
Ch. Anagnostou ◽  
I. Iliopoulos ◽  
M. Kontali
Keyword(s):  
Mediterranean Sea ◽  
Sediment Core ◽  
Eastern Mediterranean ◽  
Planktonic Foraminifera ◽  
Mineralogical Composition ◽  
Eastern Mediterranean Sea ◽  
Sediment Samples ◽  
Preliminary Results ◽  
The Core ◽  
Mineral Constituents

The present paper summarizes the preliminary results of the mineralogical and micropaleontological analysis conducted on sediment samples from core TYR05 retrieved from the anoxic and hypersaline Tyro basin in the eastern Mediterranean Sea. The core comprises a complex lithostratigraphic sequence attributed to the strong geodynamic regime of the area. The planktonic foraminifera associations present fluctuations which coincide with changes in the lithology of the core. The mineralogical composition of the sediments shows influence from the evaporites developed on the bottom of the basin. The mineral constituents in association to the microfauna assemblages suggest that the sediments include sapropelic layers. Further analyses are needed in order to determine safely the sapropelic deposits.

Boron isotope-based seasonal paleo-pH reconstruction for the Southeast Atlantic – A multispecies approach using habitat preference of planktonic foraminifera

2018 ◽  
Vol 487 ◽  
pp. 138-150 ◽  
Author(s):  
Markus Raitzsch ◽  
Jelle Bijma ◽  
Albert Benthien ◽  
Klaus-Uwe Richter ◽  
Grit Steinhoefel ◽  
...  
Keyword(s):  
Habitat Preference ◽  
Planktonic Foraminifera ◽  
Boron Isotope ◽  
Ph Reconstruction

Upper-ocean stratification of the NE South China Sea during the last 35 ka: Implications from oxygen isotope records from planktonic foraminifera

2020 ◽  
Author(s):  
Tzu-Chun Wang ◽  
Andrew Tien-Shun Lin ◽  
Horng-Sheng Mii ◽  
Chorng-Shern Horng ◽  
Christophe Colin
Keyword(s):  
High Resolution ◽  
South China Sea ◽  
Oxygen Isotope ◽  
Sediment Core ◽  
South China ◽  
Planktonic Foraminifera ◽  
Upper Ocean ◽  
Freshwater Input ◽  
Ocean Stratification ◽  
China Sea

&lt;p&gt;The sedimentation rate in the northeastern South China Sea (SCS) is high and it therefore offers an opportunity for a high-resolution paleoceanographic study. This study is based on high-resolution AMS &lt;sup&gt;14&lt;/sup&gt;C dating on forams and oxygen isotope data of two planktonic foraminifera species (&lt;em&gt;Globigerinoides ruber&lt;/em&gt; and &lt;em&gt;Neogloboquadrina dutertrei&lt;/em&gt;) from the sediment core, MD18-3568, collected from the northeastern SCS, to reconstruct upper-ocean stratification since 35 ka.&lt;/p&gt;&lt;p&gt;The marine sediment core MD18-3568 is located on the accretionary wedge off SW Taiwan at a water depth of 1,315 m, the whole core is dominated by hemipelagic sediments and is of 20.7 m in length. Samples for AMS &lt;sup&gt;14&lt;/sup&gt;C dating were selected at roughly 2 ka interval with a total of 16 samples. The ages show a continuously younging-upward trend with bottom of this core around 35,000 years BP. Samples for high-resolution oxygen isotope measurements were selected at a nominal 500-year age interval. The difference in &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O between &lt;em&gt;G. ruber&lt;/em&gt; (mixed layer dwelling species) and &lt;em&gt;N. dutertrei&lt;/em&gt; (thermocline dwelling species) is used to reconstruct the upper ocean stratification with large difference indicating significant ocean stratification and vice versa. The results show moderate upper ocean stratification during 35-24 ka, and it became less stratified during the Last Glacial Maximum (LGM, 23-19 ka). During the deglacial stage, the stratification gradually became stronger until the early Holocene (12-9 ka), and it has kept strong upper-ocean stratification since 9 ka. Literature has documented less rainfall intensity during the LGM and heavy rainfall during the Holocene in southern Taiwan. We interpret the upper-ocean stratification in the NE South China Sea near Taiwan is linked to the amount of freshwater inputs from Taiwan. Less Taiwan freshwater input during the LGM led to a weak stratified upper ocean and a large amount of freshwater input from Taiwan led to a strong upper-ocean stratification during the Holocene.&lt;/p&gt;

Boron isotope analysis of coral skeletons by laser ablation MC-ICP-MS: new insights into calcification and environmental reconstruction at high temporal resolution

2020 ◽  
Author(s):  
Gavin L. Foster ◽  
Thomas B. Chalk ◽  
Christopher D. Standish
Keyword(s):  
Laser Ablation ◽  
Trace Element ◽  
Temporal Resolution ◽  
Isotope Analysis ◽  
Coral Skeleton ◽  
Boron Isotope ◽  
High Temporal Resolution ◽  
Carbonate System ◽  
Seawater Ph ◽  
Icp Ms

&lt;p&gt;Despite being some of the largest bio-constructions on the planet, coral reefs are made by many millions of cm- to mm-sized polyps of Scleractinian corals. Calcification occurs in a micron sized space sandwiched between the coral animal and the existing skeleton, known as the extra cellular medium (ECM). The coral animal has a tight control on the carbonate system in this space through deploying enzymatic pumps (e.g. Ca-ATPase) and secreting acidic-rich proteins. Tracking the state of the carbonate system in the ECM is therefore key to forming a mechanistic understanding of how environmental change, such as ocean acidification, influences skeletal formation and ultimately the growth and resilience of these important ecosystems.&lt;/p&gt;&lt;p&gt;Traditional means to examine ECM composition is through the use of micro-electrodes. While these approaches have revealed many key insights they are, by their nature, invasive.&amp;#160; They also only provide snap shots of information for corals grown in the laboratory. The boron isotopic composition of the coral skeleton and its boron content (expressed as B/Ca ratio) have recently emerged as a viable alternative approach to fully characterise the carbonate system in the ECM.&amp;#160; However, most studies employ bulk sampling techniques which require averaging across both structural elements of the coral skeleton and many months to years of growth. Laser ablation MC-ICP-MS approaches are now available as an alternative sampling protocol (e.g. Standish et al. 2019), and along with B/Ca (and other trace element) measurements this not only allows a reconstruction of the full carbonate system of the ECM from an analysis of the skeleton of any coral (cultured or wild) at unprecedented spatial and temporal resolution, but it also allows an examination of the influence of the carbonate system in the ECM on trace element incorporation.&amp;#160;&lt;/p&gt;&lt;p&gt;Here we present boron isotope and trace element analyses of several tropical, reef-building, corals to examine the nature and magnitude of fine scale variation in ECM composition.&amp;#160; By studying corals from locations where external seawater is well known we also gain insights into trace element incorporation and whether external seawater pH can be accurately reconstructed from the boron-based proxies at weekly (or better) resolution.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Standish, C.D., Chalk, T.B., Babila, T.L., Milton, J.A., Palmer, M.R., Foster, G.L. (2019) The effect of matrix interferences in situ boron isotope analysis by laser ablation MC-ICP-MS, Rapid Communications in Mass Spectrometry 33: 959&amp;#8211;968 https://doi.org/10.1002/rcm.8432&lt;/p&gt;

δ11B and B/Ca ontogenetic variability within Globigerina bulloides

2020 ◽  
Author(s):  
Matthieu Buisson ◽  
Pascale Louvat ◽  
Szabina Karancz ◽  
Ruchen Tian ◽  
Markus Raitzsch ◽  
...  
Keyword(s):  
Size Effect ◽  
Earth Science ◽  
Isotopic Ratio ◽  
Direct Injection ◽  
Planktonic Foraminifera ◽  
Small Samples ◽  
Shell Size ◽  
Seawater Chemistry ◽  
Globigerina Bulloides ◽  
Ocean Carbon

&lt;p&gt;Understanding the atmosphere-continent-ocean carbon cycle and its associated oceanic carbon system is one of the keystones to face the Anthropocene&amp;#8217;s climate change. Since the 1990s the isotopic ratio of boron (&amp;#948;&lt;sup&gt;11&lt;/sup&gt;B) in calcitic shells of planktonic foraminifera has proven to be a powerful geochemical proxy to determine the oceanic paleo-pH and its link to atmospheric CO&lt;sub&gt;2&lt;/sub&gt; level over geological times&lt;sup&gt;1&lt;/sup&gt;, whereas the ratio B/Ca as proxy of the seawater carbonate chemistry is still questionable&lt;sup&gt;2,3&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;However, the use of planktonic foraminifera in paleoclimatic reconstructions requires calibrations of the pH &amp;#8211; &amp;#948;&lt;sup&gt;11&lt;/sup&gt;B relationships to correct what is known as &amp;#171;&amp;#160;vital effect&amp;#160;&amp;#187;&lt;sup&gt;4&lt;/sup&gt;: each species controls differently its calcification process and consequently slightly modifies the seawater chemistry during biomineralization&lt;sup&gt;5,6&lt;/sup&gt;. Moreover, shell size effect on &amp;#948;&lt;sup&gt;11&lt;/sup&gt;B has been reported for some symbiont-bearing species due to photosynthetic increase of pH&lt;sup&gt;7,8&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;Calibrations for the symbiont-barren &lt;em&gt;Globigerina bulloides&lt;/em&gt; have been already determined&lt;sup&gt;9,10 &lt;/sup&gt;but sparse data have been reported so far for the test size effect on &amp;#948;&lt;sup&gt;11&lt;/sup&gt;B &lt;sup&gt;11&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;Here we measured the &amp;#948;&lt;sup&gt;11&lt;/sup&gt;B of three different fractions (250-315, 315-400 and &gt;400 &amp;#956;m) of &lt;em&gt;G. bulloides&lt;/em&gt; sampled along the coretop PS97-122 from the Chilean margin (54.10&amp;#176;S, 74.91&amp;#176;W), by using a new protocol developed at IPGP and dedicated to small samples which couple a microsublimation technique and a micro-direct injection device (&amp;#956;-dDIHEN&lt;sup&gt;12&lt;/sup&gt;). Our preliminary results show significantly higher &amp;#948;&lt;sup&gt;11&lt;/sup&gt;B values for the large fractions compared to the small ones, as found for symbiont-bearing planktonic species such as &lt;em&gt;Globigerinoides sacculifer&lt;/em&gt;&lt;sup&gt;7&lt;/sup&gt; and &lt;em&gt;Globigerinoides ruber&lt;/em&gt;&lt;sup&gt;8&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;ul&gt;&lt;li&gt;(1) Pearson &amp; Palmer, 2000, &lt;em&gt;Nature&lt;/em&gt; 406, 695-699&lt;/li&gt; &lt;li&gt;(2) Yu et al., 2007, &lt;em&gt;Paleoceanography&lt;/em&gt; 22, PA2202&lt;/li&gt; &lt;li&gt;(3) Allen et al., 2012, &lt;em&gt;EPSL&lt;/em&gt; 351-352, 270-280&lt;/li&gt; &lt;li&gt;(4) Urey et al., 1951,&lt;em&gt; Soc. Am. Bull.&lt;/em&gt; 62, 399-416&lt;/li&gt; &lt;li&gt;(5) Erez, 2003, &lt;em&gt;Rev. in Min. and Geochem.&lt;/em&gt; 54 (1), 115-149&lt;/li&gt; &lt;li&gt;(6) de Nooijer et al., 2014, &lt;em&gt;Earth-Science Reviews&lt;/em&gt; 135, 48-58&lt;/li&gt; &lt;li&gt;(7) H&amp;#246;nisch &amp; Hemming, 2004, &lt;em&gt;Paleoceanography&lt;/em&gt; 19, PA4010&lt;/li&gt; &lt;li&gt;(8) Henehan et al., 2013, &lt;em&gt;EPSL&lt;/em&gt; 364, 111-122&lt;/li&gt; &lt;li&gt;(9) Mart&amp;#237;nez-Bot&amp;#237;et al., 2015, &lt;em&gt;Nature&lt;/em&gt; 518, 219-222&lt;/li&gt; &lt;li&gt;(10) Raitzsch et al., 2018, &lt;em&gt;EPSL&lt;/em&gt; 487, 138-150&lt;/li&gt; &lt;li&gt;(11) Henehan et al., 2016, &lt;em&gt;EPSL&lt;/em&gt; 454, 282-292&lt;/li&gt; &lt;li&gt;(12) Louvat et al., 2019, &lt;em&gt;JAAS&lt;/em&gt; 8, 1553-1563&lt;/li&gt; &lt;/ul&gt;

scholarly journals Calibration of the boron isotope proxy in the planktonic foraminifera Globigerinoides ruber for use in palaeo-CO2 reconstruction

2013 ◽  
Vol 364 ◽  
pp. 111-122 ◽  
Author(s):  
Michael J. Henehan ◽  
James W.B. Rae ◽  
Gavin L. Foster ◽  
Jonathan Erez ◽  
Katherine C. Prentice ◽  
...  
Keyword(s):  
Planktonic Foraminifera ◽  
Boron Isotope ◽  
Globigerinoides Ruber
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