Response of the Nitrogen Cycle to Ocean Redox Chemistry During the Great Oxidation Event

Lead Research Organisation: Newcastle University
Department Name: Civil Engineering and Geosciences

Abstract

One of the most fundamental questions that drives natural sciences is how life evolved on Earth. Understanding how life evolved on this planet also informs our search for habitable planets in other solar systems. What we now know beyond a reasonable doubt is that simple single-celled organisms evolved in the ocean greater than 3 billion years ago. We also know that the chemistry of the Earth's surface (both the atmosphere and the oceans) has undergone dramatic changes since that first cell division occurred. What we then seek to understand is how the evolution of life has responded to, and in some cases driven, these changes in Earth surface chemistry. Understanding how life responded to geochemical changes on the planet in the past will additionally help us to more clearly predict how life will respond to chemical changes in the future, for example associated with rapidly approaching climate change. One of the major parameters that affects life in the ocean is the availability of dissolved oxygen, which is not only essential for all higher life forms to exist, but also directly controls the distribution and abundance of essential elements that make up the building blocks of life. For the first ~3.5 billion years of Earth history, the ocean was characterized by a lack of dissolved oxygen, a situation known as anoxia. Oxygen first began to build up in the atmosphere and oceans between ~2.4 and 2.3 billion years ago, in perhaps the most dramatic event in the history of Earth surface chemistry, termed the Great Oxidation Event. It was not until ~580 million years ago that oxygen levels in the atmosphere rose sufficiently to completely oxygenate the oceans. In the intervening ~2 billion years, the chemistry of the oceans fluctuated rapidly between various levels of oxygenation. Thus a major focus for scientific research recently has been on identifying and understanding the response of biology and the cycling of essential nutrients to variable amounts of oxygen in the environment. Nitrogen is an essential element in all living organisms, required along with carbon and phosphorus for the formation of proteins, amino acids, DNA and RNA. The distribution of nitrogen in the biosphere is controlled by biological reactions that respond to environmental parameters, including the amount of available oxygen. Despite the importance of nitrogen to life, very little is known about how the nitrogen cycle responded to fluctuations in oxygen concentrations over Earth history. The aim of this project is specifically to interpret the response of the global nitrogen cycle to changes in the oxygen content of the atmosphere and oceans during the Great Oxidation Event. This will be accomplished by laboratory experiments with microorganisms that are important in the modern nitrogen cycle, and application of the results of the experimental studies to the investigation of nitrogen and indicators of oxygenation in sedimentary rocks spanning the Great Oxidation Event.

Publications

10 25 50
 
Description Catastrophic upheavals in past surface conditions provide a critical window for Earth scientists to study how the biosphere responds and evolves in response to change. The most dramatic example of such a change occurred about halfway through Earth's long history, approximately 2.3 billion years ago when oxygen (O2) first accumulated to significant levels in the oceans and atmosphere. This "Great Oxidation Event" was a prerequisite for the global biosphere that we inhabit today, as it enabled the evolution of animals and multi-cellular organisms that universally require O2 to live. Despite the significance of such a monumental event to the evolution of life on our planet, previous studies of this interval lacked the detailed resolution needed to study the biospheric response to Earth surface oxygenation, hindering our understanding of important feedbacks to chemical and biological evolution. Nitrogen and phosphorus are particularly important elements to consider, as these "nutrients" control the primary productivity of the biosphere, which in turn plays a role in regulating climate, weathering, and the amount of oxygen in Earth's surface environments over geologic timescales. Research from this project, published in Nature on 6 February, 2017, presents unique high-resolution records of nitrogen cycling in dated sedimentary rock units that define the Great Oxidation Event. Remarkably, these detailed records demonstrate the immediate onset of a modern-style nitrate-driven ecosystem, appearing simultaneously with the first evidence for O2 in the atmosphere. These data constrain the first occurrence of widespread nitrate availability, which would have provided the building blocks for rapid diversification and proliferation of nitrate-utilizing organisms, including eukaryotes, hot on the heels of global oxygenation.
Exploitation Route The project is multidisciplinary in nature, and as such will benefit a wide range of researchers interested in natural sciences, from both the biological and geological sectors. As such, the project will be of interest to disciplines as diverse as microbiology, microbial ecology, geobiology, biogeochemistry, sedimentary geochemistry, and paleoceanography. In particular, the outcome of this work will benefit the community of scientists focused on understanding the coevolution of the geosphere and the biosphere over geologic timescales, and biogeochemical nitrogen cycling. The evaluation of N isotope fractionations during important N cycling metabolisms under different conditions will be of wide-ranging interest to isotope geochemists and microbial ecologists interested in both the modern and ancient biogeochemical N cycling. Additionally, the paleoceanography community as a whole will greatly benefit from the high resolution d15N and paleordedox records we will generate across this important period of Earth history, which will provide invaluable data for future researchers to continue to scrutinize as our understanding of the dynamics of the nitrogen cycle evolves.
Sectors Environment

 
Description NERC Isotope Geosciences Facilities Steering Committee
Amount £23,500 (GBP)
Funding ID IP-1475-1114 
Organisation Natural Environment Research Council 
Department NERC Isotope Geosciences Laboratory
Sector Academic/University
Country United Kingdom
Start 01/2016 
End 01/2017
 
Title nano-EA-IR-MS at SUERC 
Description I have funded the setup of a nano-EA-IR-MS system at SUERC, to be used for carbon and nitrogen stable isotope analyses of low quantities of C and N 
Type Of Material Improvements to research infrastructure 
Year Produced 2017 
Provided To Others? Yes  
Impact This method will expand the UK's capability for measuring nano-scale stable isotope analyses, for applications in geosciences and life sciences. 
 
Description Leeds 
Organisation University of Leeds
Country United Kingdom 
Sector Academic/University 
PI Contribution We funded two sampling trips to the Pretoria core library for sampling Neoarchean, Paleoproterozoic, and Phanerozoic samples
Collaborator Contribution Use of facilities for sample prep, analyses of carbon and nitrogen isotopes; also several papers in prep from samples we collected together
Impact Zerkle, A. L., Poulton, S. W., Newton, R. J., Bekker, A., and Claire, M. W. (2014) Rapid expansion of the aerobic nitrogen cycle during the Great Oxidation Event: Nature, in revision. Izon, G.*, Zerkle, A. L., Zhelezhinskaya, Y., Farquhar, J., Newton, R. J., Poulton, S. W., Eigenbrode, J. L., and Claire, M. W. (2014) Rapid oscillations in atmospheric chemistry in the prelude to the Great Oxidation Event: EPSL, in review.
Start Year 2010
 
Description Natural History Museum 
Organisation Natural History Museum
Country United Kingdom 
Sector Public 
PI Contribution geochemistry (CNS isotopes and Fe speciation) of samples spanning the Permian-Triassic extinction event
Collaborator Contribution samples, led field expedition
Impact Mettam CM, Zerkle AZ, Claire MC, Junium C, and Twitchett R (in prep) Paleoenvironmental implications of d15N records across the arctic PT boundary (for submission to Geobiology)
Start Year 2014
 
Description SUERC 
Organisation University of Glasgow
Department Scottish Universities Environmental Research Centre
Country United Kingdom 
Sector Academic/University 
PI Contribution We will be providing samples and a trained PGR student to set up further nano-EA-irMS for N isotope analyses of small sample sizes
Collaborator Contribution They will be contributing time and instrumentation to set up nano-EA-irMS for N isotope analyses of small sample sizes
Impact Mettam, C, Zerkle, AL, Claire, MW, Newton, J, Boyce, A, and Junium, CJ (2014) Nitrogen cycling on a Neoarchean carbonate platform: Co-evolution of Life and the Planet meeting, London (poster)
Start Year 2013
 
Description Syracuse 
Organisation Syracuse University
Country United States 
Sector Academic/University 
PI Contribution We have a PGR student who has extracted kerogen from Neoarchean samples collected for my NERC fellowship and traveled to Syracuse to analyse them for N isotopes
Collaborator Contribution They have provided training and use of a nano-EA-irMS system for measuring N isotopes on very small sample sizes
Impact Mettam, C, Zerkle, AL, Claire, MW, Newton, J, Boyce, A, and Junium, CJ (2014) Nitrogen cycling on a Neoarchean carbonate platform: Co-evolution of Life and the Planet meeting, London (poster) Mettam CM, Zerkle AZ, Claire MC, Junium C, and Twitchett R (in prep) Paleoenvironmental implications of d15N records across the arctic PT boundary (for submission to Geobiology)
Start Year 2013
 
Description UMD 
Organisation University of Maryland, College Park
Country United States 
Sector Academic/University 
PI Contribution We have provided samples and initial bulk rock sulfur isotope data
Collaborator Contribution They have provided SIMS sulfur isotope data and use of Mat253 for multiple sulfur isotope work; this has resulted in one publication and several projects in prep
Impact Farquhar, J., Cliff, J., Zerkle, A. L., Kamyshny, A., Jr., Poulton, S. W., Claire, M. W., Adams, D., and Harms, B. (2013) Pathways for Neoarchen pyrite formation constrained by mass-independent sulfur isotopes: Proceedings of the National Academy of Sciences, 110 (44), 17638-17643. Zerkle, A. L., Claire, M. W., Domagal-Goldman, S. D., Farquhar, J., and Poulton, S. W. (2012) A bistable organic-rich atmosphere on the Neoarchaean Earth: Nature Geoscience 5, 359-363.
Start Year 2010
 
Description Edinburgh Science Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact In April 2016 I gave a public seminar at the National Museum of Scotland, within the theme "Life in the Extremes" at the Edinburgh Science Festival.
Year(s) Of Engagement Activity 2016
URL http://www.whatsoninedinburgh.co.uk/event/029858-life-in-the-extremes/
 
Description Elements Magazine 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Article in the Magazine, Elements:
Lyons, T., Fike, D., and Zerkle, A. L. (2015) Emerging biogeochemical views of Earth's ancient microbial worlds: Elements 11 (6), 415-421.
Year(s) Of Engagement Activity 2015
 
Description Invited Public Lecture - Edinburgh Geological Society 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact 50 members of the public and professional geologists attended this lecture, which sparked questions and discussion afterwards.
Year(s) Of Engagement Activity 2017
 
Description Invited Public Lecture - St Andrews Open Association 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact 50 members of the local public attended this public lecture, which sparked questions and discussion afterwards.
Year(s) Of Engagement Activity 2017
 
Description Media coverage 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Local press release resulting in international media coverage. Listed in the top 5% of all research outputs scored by Altmetric; picked up by 6 news outlets (including the National), 3 blogs, 66 tweeters, and 2 Redditors.
Year(s) Of Engagement Activity 2017
URL http://www.thenational.scot/news/15075295.New_research_at_St_Andrews_reveals_insight_into__most_dram...