nom_organisme nom_organisme nom_organisme nom_organisme

  William Gray

   Archives et Traceurs

   Paléocéanographie

   tel.jpg 01.69.08.39.56
   fax.png 01.69.08.77.16
   email.gif

I am a Research Scientist in the Paleoceanography group at LSCE. I use the chemical composition of foraminifera (small marine calcifiers) to understand past climate change. 

Follow me on twitter @willerstorfi.

A complete publication list is available on Google Scholar

A web app version of MgCaRB (a tool to covert Mg/Ca to SST accounting for pH and salinity) is available here and the R/Matlab code is available here and here

 

things keeping me occupied

Development and application of foraminiferal trace element proxies (including Mg/Ca)

Sargasso Sea sediment trap
Mg/Ca SST(colours) with measured SST (grey) at the Sargasso Sea sediment trap

 

My work looks at calibrating Mg/Ca in planktic foraminifera, assessing the non-thermal influences, and understanding how we can use Mg/Ca as an accurate paleothermometer. I am also interested in using trace elements to understand how foraminifera biomineralise, and as proxies for the carbonate-system.

The data from our 2018 global sediment trap study is available here.

A web app version of MgCaRB (a tool to covert Mg/Ca to SST accounting for pH and salinity) is available here and the R/Matlab code is available here and here

 

Boron isotopes and carbon cycling

stack of surface ocean pH and pCO2
Stack of surface ocean pH and pCO2 from boron isotopes showing deglacial CO2 outgassing
(Shao et al,. 2019)

Boron isotopes in foraminifera track seawater pH, giving us a powerful tool to reconstuct past CO2 concentrations. I use boron isotopmes to understand the oceans role in driving Glacial-Interglacial changes in CO2. I am currently developing the foraminiferal boron isotope method at LSCE.

 

 

 

 

 

Using spatial patterns of δ18O to reconstruct past climate dynamics

I am using basin-scale compilations of planktic foraminiferal δ18O and climate models to look changes in atmospheric and surface ocean circulation over deglaciation. Using these methods we showed a 3° southward shift the subtropical/subpolar gyre boundary and westerly winds in the North Pacific durint the LGM (Gray et al., 2020). I am currently applying these methods to the Southern Ocean, and future plans involve the North Atlantic! 

Tracking the latitudinal movement of the gyre boundary in the North Pacific over deglaciation using the spatial pattern of δ18O

 

pelagic calcifiers in the modern ocean

Carbonate production by pelagic calcifiers removes alkalinity from the surface ocean and exports it to the deep ocean, however estimates of how much calcium carbonate is produced, who makes it (forams/coccos/pteropods), and how much of it makes it into the deep ocean/sediments vary wildely; as part of the CDisk-4 cruise, we are trying to figure out how much carbonate is produced by foraminifera, coccolithophores, and pterpods, and how much of this sinks into the deep ocean. New results soon! 

Pteropods produce aragonite and look cool
Pteropods from a plankton tow sample. They produce aragonite, and look cool.

 

Retour en haut