Projects Uni Bremen
MArine radioCArbon Reservoir Alter (MACARA)
DFG Project 1.4.2022-31.3.2025 by Gerrit Lohmann
Team: Gerrit Lohmann, Martin Butzin, Edouard Bard
We reconstruct the distribution of radiocarbon at the sea surface with unprecedented temporal and spatial resolution and simulate it using a novel multi-scale climate radiocarbon model. This will allow marine data to be corrected and hypotheses about abrupt climate changes during the last ice age to be tested.
The Marine Reservoir Effect in C-14 is a phenomenon that works as a proxy for several climate-related parameters. Still, the MRE remains understudied in many locations around the globe, limiting our understanding of the global carbon cycle and how it responds to climate change. Taking advantage of the state-of-the-art facilities available in the host institutions, the investigators will be able to achieve high-quality data that are much needed at this moment of profound changes in climate. Indeed, by providing the quantification of the MRE for key locations in the main ocean basins, the MARCARA project aims to fill a long-standing gap in radiocarbon research. The project combines both experimental data acquired in the lab with numerical modelling, which is a powerful combination that will strengthen the outcomes of the project. This type of approach has been successfully used in climate research and remains crucial for the understanding of climate evolution in different timescales. Focusing on the last deglacial, which is a key period for understanding the Earth Climate System, the project is an ambitious undertaking that has the potential to enhance our knowledge of the climate system stimulating new research on a variety of topics, ranging from archaeology and cultural heritage to the geosciences. By providing these data, the MARCARA project is likely to positively impact the radiocarbon community helping to unravel the mechanisms involved in climate variations over the past.
- Atmospheric radiocarbon concentrations in terms of F14C (the
fractionation-corrected and normalized 14C/12C ratio) according to the
Hulu Cave speleothem record (Cheng et al., 2018; Southon et al., 2012).
Upper and lower curves span the uncertainty range (mean values ±2σ). b)
Ensemble simulations of marine 14C for the past 50 kyr forced with
atmospheric F14C according to Hulu Cave, shown is the period where 14C
dating is not further constrained through continuous tree ring 14C
records. (c) Corresponding ensemble simulations of marine 14C expressed
as 14C age with respect to the contemporaneous atmosphere (the Marine
Reservoir Age); values are averaged between 50°N and 50°S. CS, GS, and
PD specify different ocean states with weak, intermediate, and strong
overturning (Butzin et al., 2020). (d) Marine reservoir age simulated
for the Last Glacial Maximum; shown is the ensemble median of the
transient simulations. Filled circles are foraminifera-based marine
reservoir ages compiled by Skinner et al. (2017). Source
Publications:
German version:
Wir werden die Verteilung von Radiokohlenstoff an der Meeresoberfläche mit bisher nicht gekannter zeitlicher und räumlicher Auflösung rekonstruieren und mit Hilfe eines neuartigen multiskaligen Klima-Radiokohlenstoff-Modells simulieren. Dadurch können marine Daten korrigiert und Hypothesen über abrupte Klimaveränderungen während der letzten Eiszeit getestet werden.
DFG Projekt: MArine radioCArbon Reservoir Alter
EXC 2077: The Ocean Floor – Earth’s Uncharted Interface
Subject Area: Atmospheric Science, Oceanography and Climate Research Geology and Palaeontology, Mineralogy, Petrology and Geochemistry
Term: 2019-2025
The ocean floor, which makes up 71% of the Earth’s solid surface, lies an average of 3,700 meters beneath the ocean surface. The difficulties related to accessibility necessitate ship expeditions and the use of highly specialized underwater equipment for its exploration. As yet, only a small fraction of the ocean floor has been scientifically investigated, but it is already known that this supposedly passive environment is an important interface with a wide range of functions that impact the entire Earth system. Geological, physical, biological and chemical processes interact at and within the ocean floor, thus influencing the climate system, the global carbon cycle, and biological productivity in the world ocean. We still know too little about ocean-floor processes to compile detailed global mass budgets. The Cluster aims to initiate a new chapter in ocean-floor research by quantifying exchange processes at this significant boundary layer and their roles in the Earth system. This will be achieved by: (i) deciphering processes that control the transport of biogenic particles to the ocean floor and their transformation under changing climate conditions, (ii) balancing the transfer of carbon and other elements between the ocean floor and seawater, (iii) understanding how ocean-floor ecosystems react to environmental changes, and (iv) developing scenarios for a “warmer-than-present world” from ocean-floor climate archives with the help of climate models.
Dekadische Zyklen in eiszeitlicher Winddynamik - Rekonstruktion aus jährlich laminierten Eifelmaarsedimenten und Vergleich mit zeittransienten Modellsimulationen (13.000 - 43.000 yr b2k)
Changes in wind systems and atmospheric circulation play a critical role in driving abrupt climate and weather changes, leading to hemispheric-wide teleconnections. Understanding these dynamics is crucial for predicting future climate scenarios and mitigating the impacts of extreme weather events. In this research proposal, we aim to investigate the synoptic interpretation of prevailing paleo wind systems in Europe during glacial periods, with a focus on comparing the paleo wind patterns with proxy records from the Eifel Region, Germany. By examining millennial-scale data, we seek to elucidate the changes in wind direction and frequency, particularly during Marine Isotope Stage 3 (MIS-3) and MIS-2.
Expected outcome:
• A comprehensive understanding of paleo wind systems and their impact on climate and weather changes in North-Western Europe during glacial periods.
• Validation of model simulations against proxy records, enhancing the reliability of climate models in predicting extreme events.
DFG Project 1.1.2025-31.12.2027 by Gerrit Lohmann
(LO 895/21-1 | SE 1928/2-1 | SI 594/38-1)
Projektnummer: 550972244
Team: Professor Dr. Gerrit Lohmann, Bremen, Dr. Klemens Seelos, Professor Dr. Frank Sirocko, Mainz; NN