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UCL Home  /  Geography  /  News & Events  /  News  /  News Archive  /  2016  /  June 2016  /  The changing ocean and its impact on deep-sea ecosystems

The changing ocean and its impact on deep-sea ecosystems

David Thornalley's Keynote Lecture in Boulder and further research funding

The changing ocean and its impact on deep-sea ecosystems

In May 2016, UCL Geography’s Dr David Thornalley was invited to present a keynote talk at an international workshop, hosted by the US Climate Variability and Predictability Program (US CLIVAR), in Boulder, Colorado.

The workshop focussed on the Atlantic Meridional Overturning Circulation (AMOC) – the conveyor belt-like circulation of the Atlantic Ocean which helps warm Northwest Europe and regulates Earth’s climate.

It has long been recognized that changes in the AMOC have played a key role in abrupt climate events in the past, such as during the last Ice Age. Climate models also suggest that the AMOC may be vulnerable to future collapse because of Greenland ice sheet melting and changes to the hydrological cycle. Our instrumental observations of this crucial component of the climate system only stretch back a decade, but these suggest the AMOC is undergoing substantial weakening. Is this due to changes in Earth’s climate caused by global warming, or just part of natural multi-decadal variability?

The workshop brought together researchers from the physical oceanography and paleoceanography communities to synthesise existing knowledge, and plan future strategies for developing our understanding of AMOC variability on decadal to centennial timescales. Ultimately, the aim is to improve predictions of AMOC behaviour. David’s talk presented data highlighting what we can learn about past AMOC variability from palaeoceanographic records.

Simply understanding the nature of AMOC variability is not the main goal, however. We are more interested in the impacts of any significant change in the AMOC on human societies and natural ecosystems. For example, the North Atlantic harbours a biologically rich variety of life and ecosystems that help secure the well‐being and economic security of Atlantic nations and their citizens. Yet it is likely that this habitat will be significantly altered if the AMOC weakens (or maybe ‘continues to weaken’?!).

As part of a recently established EU consortium programme, ‘ATLAS’ (,  David, with others at UCL, has been awarded a £132,000 grant to research past AMOC variability and its effect on deep-sea ecosystems. This will feed into the wider remit of the EU ATLAS programme, investigating the response of deep sea ecosystems to both past and future changes in the AMOC. This examines interconnections between ocean circulation, surface production, and the functioning, biological richness and socioeconomic importance of Atlantic ecosystems. Watch for future new and exciting findings from this project!

Figure: A simplified schematic of the AMOC, with the 10 year time series of AMOC strength at 26.5 oN, obtained from instrumental observations, indicating a ~20% decline (Srokosz and Bryden, Science, 2015).

See: US Clivar Paleo Clivar:


The AMOC (see below)

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David Thornalley