Deciphering the Signal of Arctic Climate Change
<jats:p> &lt;p&gt;Whether or not Arctic regions remain(ed) a carbon sink or source to the atmosphere during rapidly warming climates (in the past) is a fundamental question with regards to future global warming and ocean acidification. The boron isotopic composition of planktonic foraminiferal shell calcite (&amp;#948;&lt;sup&gt;11&lt;/sup&gt;B&lt;sub&gt;Cc&lt;/sub&gt;) can potentially provide valuable information of past seawater pH if information on a second carbonate system parameter, temperature, and salinity is available. However, most applications of palaeoceanographic proxies to the cold polar oceans are limited due to a paucity of calibration data, limited information on the calcification habitat, and secondary effects of the carbonate system on the temperature recorded by Mg/Ca values measured in the dominant Arctic species Neogloboquadrina pachyderma sinistral (NPS). Here we present a new Multi-Collector Inductively Coupled Mass Spectrometry (MC-ICPMS) &amp;#948;&lt;sup&gt;11&lt;/sup&gt;B dataset measured on live NPS collected via plankton tows from the Labrador Sea and Baffin Bay. We compare our results with &amp;#948;&lt;sup&gt;11&lt;/sup&gt;B&lt;sub&gt;borate&lt;/sub&gt; derived from pH measurements, &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C DIC seawater values, temperature and salinity collected at the time and depth the foraminifera calcified. To quantify the control of low carbonate ion concentration on Mg/Ca derived temperatures we measured B/Ca alongside Mg/Ca in the calibration dataset. We are thus able to present a new geochemical correction scheme that can isolate non-thermal controls on the Mg/Ca-temperature relationship for NPS, allowing us for the first time the reconstruction of carbonate system parameters in the Arctic Ocean.&lt;/p&gt; </jats:p>
Morley_2020_Deciphering the Signal of Arctic Climate Change.pdf - Other
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