Paleo Dust

 

Much of my recent research has focused on understanding the natural variability of dust and its impact on global climate. I am involved in reconstructing changes in the magnitude and provenance (source) of dust input to the ocean and the Antarctic ice sheet.



May 16, 2016

Ocean dynamics, not dust, have controlled equatorial Pacific productivity over the past 500,000 years


Our new paper in the Proceedings of the National Academy of Sciences presents paired records of dust flux and export production from three sites across the equatorial Pacific and shows that ocean dynamics, rather than dust input, control biological productivity over the past five ice age cycles. We take advantage of Earth’s own repeated natural iron fertilization experiments over the past 500,000 years to conclude that dust-born iron was not a key player in driving the carbon cycle in the tropical Pacific. Purposefully adding iron to the tropical Pacific, one of the proposed geoengineering efforts, will not work to mitigate the anthropogenic increase in atmospheric carbon dioxide. For more on the implications on iron fertilization, please click here 


   





DUST in the SUBANTARCTIC PACIFIC


Our new paper in Science (Jan 24, 2014 issue) presents a record of dust supply to the Pacific sector of the Southern Ocean for the past one million years, derived from a suite of deep-sea sediment cores. Dust deposition during glacial periods was 3 times greater than during interglacials. Click here for more information.




*****************************************************************************************************************




DUST in the TROPICAL PACIFIC




Click here for our 2008 paper in Science


Click here for the news feature/press release


Click here for NY Times ‘Week in Science’


Why is dust important?

Dust influences climate by altering the radiation budget of the atmosphere, and influences marine biogeochemistry by providing a source of essential micronutrients such as iron. research on the role of dust in the past has been hampered by the scarcity of well-resolved internally consistent records of dust deposition, particularly at low latitudes.


What’s new?

Using novel proxy techniques (Th-232, He-4) to reconstruct dust fluxes in tropical Pacific sediments we find remarkable consistency over the past 500,000 years  among sites spanning more than a quarter of Earth’s circumference, as well as between tropical regions and Antarctica. Our evidence for synchronous response to climate change by interhemispheric dust sources provides, for the first time, a quantitative basis for  evaluating the role of dust in past climate change and in climate-related changes in marine biogeochemical cycles.


For more information, please contact Gisela Winckler (winckler(at)ldeo.columbia.edu).

 

This satellite image shows dust blowing off of mainland China over the Sea of Japan, the islands of Japan itself, and out into the Pacific Ocean (Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC)