Our Research Agenda
Central research objective: to assess large scale ocean-atmosphere climate dynamics during past warm climates to improve our understanding of future climate change.
To address this objective the MorPalaeo Lab research agenda concentrates on two avenues:
(1) Refining techniques in palaeoceanography to provide more reliable reconstructions of the extent and magnitude of past changes in climate, and
(2) Applying a multiproxy approach to past climate reconstructions, including isotope and trace metal geochemistry, foraminiferal assemblage counts, and the analysis of marine sediments.
Current Research Projects
Uncovering the Magnitude of Arctic Climate Change
Dr. Audrey Morley
A key challenge in climate change science is to provide informed constraints on the magnitude of future climate change. Uncertainties associated with such predictions remain large due to the shortness of our observational records (at best 150 years) and the absence of large climate shifts therein to serve as an analogue for future change. This is especially problematic when estimating Arctic climate change because the response in the Arctic is amplified relative to the global mean, making the Arctic the most sensitive and vulnerable environment with regards to global warming. Efforts to assess the magnitude of past (e.g. pre-industrial) climate changes using climate proxies are thus crucial to further our understanding of how the Arctic system will respond to continued global warming. This investigation seeks to constrain the magnitude of Arctic amplification by quantifying the influence of the carbonate ion concentration of sea water on the temperature signal recorded in the Arctic planktonic foraminifera Neogloboquadrina pachyderma sinistral (NPS). Using NPS shells collected from stratified plankton samples, we will combine established and new analytical techniques in trace element and isotope geochemistry to derive and isolate carbonate system parameters from the climate signature recorded in NPS. This approach is innovative and interdisciplinary as it takes advantage of cutting edge knowledge in proxy development without compromising on the benefit of a seasonally and spatially constraint dataset. This will provide a holistic understanding of how changing hydrological and other environmental conditions impact not only NPS lifecycle but also the geochemical signal recorded in their shell. Given the uncertainties associated with available paleoceanographic tools this will provide a major advancement in the field of paleoceanography and climate change science.
Funded through the
Constraining the Impact of Arctic Amplification in the Nordic Sea: A Biogeochemical Approach
Dr. Audrey Morley
Monitoring and expanding our knowledge of marine Essential Climate Variables (ECV) is a priority outlined in national policy documents (e.g. Innovation 2020, The EPA Report 223, Harnessing our Ocean Wealth, JPI Oceans) to obtain a “deeper understanding of atmospheric and oceanic systems, the relationships between them, and human impacts on them”. This research will support global efforts to improve our understanding of ECVs in the Nordic Seas, which is a key region for the formation of North Atlantic Deepwater and the uptake of atmospheric carbon dioxide (pCO2). Whether or not the Nordic Seas will remain a carbon sink during rapidly warming climates is a fundamental question that remains to be answered. Equally concerning is the potential of acidification and de-oxygenation of North Atlantic Deep Waters that may irreversibly damage vulnerable deep-sea habitats and their biodiversity. The research project will define a more comprehensive description of biogeochemical processes in the Nordic Seas and will provide transformative insights into how ECVs are recorded in geologic archives to improve the “long-term monitoring, surveying and modelling to understand the processes and feedback mechanisms between the ocean and atmospheric systems” (JPI Oceans).
Funded through the
Decoding Arctic Climate Change: From Archive to Insight
Dr. Jess Crumpton-Banks & Dr. Audrey Morley
In conjunction with Cruise CIAAN to the Nordic Seas in August-September 2020 on RV Celtic Explorer, project ACCAI aims to develop new palaeoceanographic tools that will enable us to monitor long-term processes in atmosphere-ocean CO2 exchange and climate change. Specifically, ACCAI intends to determine how the signature of Essential Climate Variables (e.g. temperature, salinity, and the carbonate system) are recorded in the Nordic Seas and transferred into geologic archives (marine sediments). To track the climate signal from the water to the archive we will combine a hydrographic survey in the Nordic Seas with the collection of live foraminifera collected via plankton tows and recently deposited foraminifera in surface marine sediments. Using new developments in isotope and trace element geochemistry, we will then be able to tease out the climate signal recorded in the shells of the foraminifera.
The scientific objectives of ACCAI are unique as they will provide not only observation of modern Essential Climate Variables (ECV) but will allow us to look into the past to assess how ECV’s have evolved since before pre-industrial conditions. This long-term perspective is crucial in order to deconvolve natural variability of the climate system from anthropogenic climate change. Improving our understanding of how the atmosphere-ocean climate system communicate ECVs today and in the past will aid us to better understand our environment and the environmental consequences of human activities.
Project ACCAI brings together researchers from, the University of Southampton, National Oceanographic Centre (Southampton, UK) the Bjerknes Centre for Climate Research (Bergen University, Norway) and NUI Galway.
Funded through the
Assessing High-Impact Climate Events During
Warmer than Present Environments
My research investigates the impact and variability of warmer than present environments for north-western Europe. The overall aim of this research is to assess the response of natural modes of climate variability: the Atlantic Multidecadal Oscillation (AMO) and the Atlantic Meridional Overturning Circulation (AMOC) during periods of enhanced warming in the Arctic. Targetingtwo interglacial periods of the past 500 thousand years, namely the Holocene (11.7 thousand years ago– present) and MIS 11 (~390– 440 thousand years ago), the reconstructions will enable us to identify baseline conditions during periods of enhanced warming of the climate system.
The AMO is a basin wide observation of sea surface temperatures in the North Atlantic Basinthat captures the complex processes involved in the coupled ocean-atmosphere system. It records the variability of atmospheric modes on multidecadal timescales (e.g. the North Atlantic Oscillation, the East Atlantic pattern and the Scandinavian Pattern) as well as subpolar gyre dynamics and circulation of North Atlantic water masses. The AMOC is a system of surface and deep water circulation in the Atlantic basin that links the ocean and the atmosphere. The surface water, North Atlantic Current (NAC) transfers warm, saline waters poleward. The North Atlantic Deep Water (NADW) transports cold, saline waters southwards at depth. This circulation is crucial to Europe’s climate. As the warm NAC reaches the mid-latitudes it releases heat and warms the atmosphere. Through this ocean-atmosphere heat flux the NAC aids in the maintenance of temperate climates of north-western Europe.
Using a multiproxy approach (sortable silt analysis, geochemical analysis (paired Mg/Ca - δ18O), X-ray fluorescenceanalysis, rare earth analysis and assemblage counts on both benthic and planktonic foraminifera) will facilitate the reconstruction of past changes in ocean-atmosphere climate dynamics. This will enable the inference of the impact of warmer than present environments on the AMO, the AMOC and thereby our climate in north-western Europe.This research is timely as it is unclear how Ireland’s climate will react within a warming world.
Providing Insights from Climate Archives: a Multiproxy
Approach for the Reconstruction of AMOC Response to
Quaternary Climate Events
Our limited understanding of how the climate system is (will) responding to current (future) rates of anthropogenic
global warming is linked to insufficient data from past environmental responses to a changing climate. It has been hypothesised that enhanced high-latitude warming in response to global warming may lead to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC); an important part of the climate system which plays a crucial role in oceanic northward heat transport that maintains a mild climate for the Northern Hemisphere, including Ireland. An abrupt slowdown of the AMOC has thus the potential to significantly impact our climate in Europe and beyond. However, to date there are no palaeoclimate or modelling studies that can confirm this hypothesis for warmer-than present environments. This gap has led to large uncertainties when estimating the variability of AMOC-related climate events in the future and illustrates that our understanding of the precise mechanisms linked the AMOC and climate in times of abrupt change remain limited. Here I propose to investigate abrupt events that occurred during transitions between warm-interglacial to cold-glacial conditions of the Quaternary during low ice volume conditions. A key methodological approach of the proposed work is to assess both the response of the surface and deep branches of the AMOC within the same samples that were taken from an exceptionally high-resolution climate archive (DSDP 610). This will allow me to constrain the temporal structure and elucidate mechanisms driving the AMOC during climate events. The proposed research and expected scientific discovery presented here will provide a comprehensive understanding of past environmental changes in connection to ocean circulation and climate variability, supporting improved forecasting abilities and scenario development when estimating the likelihood of an AMOC-related event occurring in the future.
Reconstructing Oceanic Carbon Dioxide Uptake
in the Eastern North Atlantic during three interglacial
periods: A model-data comparison.
Although atmospheric carbon dioxide is one of the largest contributions to global warming, the vast majority of the global budget of carbon dioxide is stored in the deep ocean through North Atlantic Deep Water (NADW) formation, providing the oceans with the capacity to control the uptake of carbon dioxide. However, it remains uncertain how(if) the ocean is going to continue absorbing atmospheric carbon dioxide in a warming future, especially since current predictions do not take into account changing rates in oceanic carbon dioxide sequestration. This research aims to help disentangle this 40 years old dilemma by looking at how the Eastern North Atlantic contributed to regulate the exchange rate of carbon dioxide between the ocean and the atmosphere during previous interglacial periods. The information obtained will serve to improve current climatic models, which will allow policy makers to create more effective mitigation plans against the consequences of global warming.
Assessing the Response of the AMOC During Times of Abrupt Climate Change
Megan Murphy O'Connor
Due to the short time-series of our observations (~150 years) and lack of an abrupt climate event occurring during this time, the precise response of the Atlantic Meridional Overturning Circulation (AMOC) to abrupt changes in climate cannot yet be determined. This gap in knowledge has led to large uncertainties when estimating AMOC variability in the future (e.g. IPCC51) and to widespread complacency when addressing the threats of global climate change. The Climate Change Advisory Council (CCAC) of Ireland stresses that we need to focus our research efforts on understanding the potential risks high-impact events associated with the AMOC may have for Ireland.
The proposed project addresses these goals using an interdisciplinary research strategy that is central to palaeoceanographic research. The proposed methodologies combine isotope and trace metal geochemistry, palaeoecological techniques, with physical grain size analysis to reconstruct the response of the AMOC to abrupt climate change under various boundary.
Assessing Diagenesis in Arctic Foraminifera
Although geographically remote, the Arctic plays a large role in the thermal regulation of the Northern hemisphere. A better understanding of Artic environments is therefore vital to climate change research. Foraminifera are marine calcifying protist and constitute a significant portion of the fossil record due to their abundance and preservation in the ocean and marine archives. As a result, they are commonly used for reconstructing past environments. Several geochemical techniques such as the trace elemental and isotopic composition of foraminiferal calcite are established palaeoceanographic techniques to reconstruct past seawater properties (e.g. temperature, salinity, carbonate chemistry). However, the interpretation of these chemical proxies relies on the assumption that there is little to no modification of the geochemical composition within the biogenic calcite after calcification, deposition, and burial at the seafloor (e.g., early diagenesis).
For example, Mg/Ca - palaeothermometry is an established tool for the reconstruction of past SSTs. However, magnesium preferentially dissolves over calcite. Early processes of dissolution and remineralization can therefore potentially alter the Mg/Ca composition of foraminifera in marine archives. Using SEM-EDS elemental mapping and 2D high resolution image analysis of recently deposited foraminifera, this research investigates whether early diagenesis at the sea floor impacts the Mg/Ca signature recorded in planktonic foraminifera deposited in the Nordic seas.