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Biogeochemical Controls on the Redox Evolution of Earth`s Oceans and Atmosphere

Abstract.

"The redox state of Earth’s atmosphere has undergone a dramatic shift over geologic time from reducing to strongly oxidizing, and this shift has been coupled with changes in ocean redox structure and the size and activity of Earth’s biosphere. Delineating this evolutionary trajectory remains a major problem in Earth system science. Significant insights have emerged through the application of redox-sensitive geochemical systems. Existing and emerging biogeochemical modeling tools are pushing the limits of the quantitative constraints on ocean–atmosphere[...]"


Source: Elements
Authors: Christopher T. Reinhard et al.
DOI: https://doi.org/10.2138/gselements.16.3.191

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Phosphorus-limited conditions in the early Neoproterozoic ocean maintained low levels of atmospheric oxygen

Abstract.

"The redox chemistry of anoxic continental margin settings evolved from widespread sulfide-containing (euxinic) conditions to a global ferruginous (iron-containing) state in the early Neoproterozoic era (from ~1 to 0.8 billion years ago). Ocean redox chemistry exerts a strong control on the biogeochemical cycling of phosphorus, a limiting nutrient, and hence on primary production, but the response of the phosphorus cycle to this major ocean redox transition has not been investigated. [...]"

Source: Nature Geoscience
Authors: Romain Guilbaud et al.
DOI: 10.1038/s41561-020-0548-7

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The Oceans Are Warming Even Faster Than We Previously Thought

"The oceans have long been considered our planet's heat sponge - a 2014 report from the Intergovernmental Panel on Climate Change (IPCC) stated that the oceans had absorbed 93% of the excess heat that greenhouse gases have trapped within the Earth's atmosphere. However, a recent study shows that the world's oceans have absorbed 60% more heat over the past 25 years than initially thought. [...]"

Source: Forbes
Author: Priya Shukla

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Quantification of ocean heat uptake from changes in atmospheric O2 and CO2 composition

Abstract.

"The ocean is the main source of thermal inertia in the climate system. During recent decades, ocean heat uptake has been quantified by using hydrographic temperature measurements and data from the Argo float program, which expanded its coverage after 2007. However, these estimates all use the same imperfect ocean dataset and share additional uncertainties resulting from sparse coverage, especially before 2007.  [...]"

Source: Nature
Authors: L. Resplandy et al.
DOI: 10.1038/s41586-018-0651-8

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