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PO2 - Past Ocean Oxygenation

Launch
 
 
Synthesis
 
 
 
 
Feb 2024
2024
2025
Feb 2027
Scientific goals
People
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Figure 1: Vertical distribution of modern dissolved oxygen (μmol/kg) along an ocean cross-section connecting the Atlantic, Southern, and Pacific Oceans.

Figure 1: Vertical distribution of modern dissolved oxygen (μmol/kg) along an ocean cross-section connecting the Atlantic, Southern, and Pacific Oceans. Reconstructed using GLODAP bottle data.

Summary

The working group’s scientific goal is to provide crucial insights into the natural variability of seawater dissolved oxygen concentrations during key time periods in the geological record. It will allow us to constrain the influence of climate, paleoproductivity, and paleocirculation on the marine oxygen cycle and related nutrients (carbon, nitrogen, phosphate, iron). Harnessing paleoceanographic records to answer questions regarding the potential links between warming and marine deoxygenation is a core need. 

Goals

1) Determine the climate impact during the last glacial period (and deglaciation) on global ocean oxygenation, oxygen distribution
2) Investigate what lessons notable hypoxic events from the geologic past hold for the future
3) Assess if the drivers of coastal hypoxia in the common era have changed as a result of human activities

Figure 2: cGENIE Earth system model results for the Late Cretaceous Oceanic Anoxic Event 2 (OAE2). (a) Simulated seafloor oxygen concentrations superimposed with observations. Green contour indicates simulated oxygen concentration of 5.0 μmol/kg, defining the region of seafloor anoxia. (b) Simulated total organic carbon (TOC) concentrations at 1-m sediment depth superimposed by observations, indicating widespread preservation of organic carbon-rich sediments under anoxic conditions, so-called black shales. Adapted from Hülse et al. (2019).

PO2

Timeline for phase I:

We anticipate holding annual hybrid workshops (3-5 days) each focusing on one objective. Data and model synthesis for each objective will take place over the ~12 months following the workshop with the goal to submit a synthesis paper on the topic within 24 months. 

Workshop 1 on “Ice sheets, ocean oxygenation and the carbon cycle” is planned for autumn 2024 in Bristol, UK; 
Workshop 2 on “Lessons from past hypoxic events.” will be held in 2025; and 
Workshop 3 on “Coastal hypoxia in the Common Era” in 2026.

For each workshop we will identify subgroups leading data and model synthesis. During the first workshop we will also initiate discussions around structuring a PO2 community discussion paper, which will define key questions, data gaps and targets in paleo-oxygen research. This community discussion paper is planned for publication in early 2028 and will be used as a guideline for the second phase of PO2.

The anticipated outcomes of the first phase will include at least four peer-reviewed articles: 
1) a whole-ocean synthesis and proxy-model comparison of the Last Glacial Period and deglacial oxygenation, 
2) a review of how and why hypoxic events like OAE’s have occurred in the deeper geologic past based on data and model synthesis, 
3) a synthesis of Common Era coastal hypoxia, and 4) a community discussion paper, defining key questions and targets to contribute to further our mechanistic understanding of the ocean oxygen cycle and future assessments.

Coordinators

Steering Group members:

Babette Hoogakker (The Lyell Centre, Heriot-Watt University, UK)
Catherine Davis (North Carolina State University, USA)
Jorge Cardich (Cayetano Heredia Peruvian University, Peru)
ECR Xiaoyi (Gloria) Guo (Ocean University of China, Qingdao, China)
David Naafs (University of Bristol, UK)
Katrin Meissner (University of New South Wales, Australia)
Christopher Somes (GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany)
ECR Simone Moretti (Max Planck Institute for Chemistry, Mainz, Germany)
 

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