Research Area: Palaeoclimate, Palaeoclimatology and rapid climatic events

Holocene changes in the strength of the Nordic Seas Overflows

The overflow of cold, dense water from the Nordic Seas into the North Atlantic plays a critical role in the global thermohaline circulation, and the compensating inflow of Atlantic surface waters helps warm NW Europe. Using grain size data from cores taken south of Iceland, I am investigating the strength of the eastern Nordic Seas overflow throughout the Holocene (~0-11,000 years ago), examining likely controls and effects. With collaborators from WHOI, we collected new cores on a cruise in May 2014. These cores are being used to examine changes in the overflows over the past 2000 years, focussing on whether or not there have been any changes between the Little Ice Age and the present day.

Deglacial changes in the circulation of the Northeast Atlantic and Arctic Mediterranean

The termination of the last Ice Age was accompanied by abrupt changes in ocean circulation. The Northeast Atlantic in particularly was subject to dramatic reorganisations that are thought to have had an impact on global climate evolution through this period. I am calibrating and using elemental ratios in benthic foraminifera to constrain changes in the physical and chemical properties of the Northeast Atlantic and Nordic Seas. I am also using benthic radiocarbon dating to help constrain the ventilation of this oceanographic region since the last glacial.

Subpolar gyre dynamics during the Holocene

The strength of the North Atlantic’s subpolar gyre varies on annual to millennial timescales and it is likely involved in feedback mechanisms that impact atmospheric circulation and the overturning circulation of the ocean. In collaboration with scientists from Cardiff University, we are investigating how the circulation of subpolar gyre changed on decadal timescales throughout the last 2,000 years, as well as investigating millennial scale changes throughout the Holocene.

Contact Name: 
David Thornalley