The greatest animal radiation on Earth was promoted by a stable marine redox landscape

October 3, 2022Outreach, Publication

The greatest rise in marine biodiversity in all of Earth’s history surprisingly was not fuelled by ocean oxygenation. Instead, oceanic redox stability appears to have favoured increased ecosystem resilience and – ultimately – a massive rise in global biodiversity levels. Oxygen rise occurred later… PhD student Alvaro del Rey measured the uranium isotope composition of … Read More

Tracing global ocean oxygenation from calcitic brachiopods

August 4, 2020Publication, Research, Students and postdocs

The uranium isotope composition of seawater provide insights to how much sediment burial occurs globally in anoxia settings. Therefore, it is desirable to measure uranium isotopes to track the oxygenation state of the oceans through geological time. However, there is currently no geological archive that can reliably record the composition of ancient seawater. Calcitic brachiopods … Read More

New paper: The impact of land plant evolution on Earth’s climate and oxygenation state

May 14, 2020Publication, Research

The colonization of land by plantss, fungi and animals has had a profound impact on Earth’s climate and oxygenation state. In a comprehensive review paper, we have summarize the current state of knowledge and compiled available evidence in support that terrestrial life has caused: Atmospheric CO2 decline and climatic cooling (permanent transition) Atmospheric O2 rise … Read More

New GCA paper: Volcanic eruptions triggered repeated marine anoxia and reveal global-scale feedbacks during the Permian-Triassic mass extinction 250 million yeers ago

April 18, 2020Publication, Research, Students and postdocs, Uncategorized

The largest animal extinction event in recorded history occurred 251 Ma at the Permian-Triassic boundary coinciding with expansive marine anoxia. In a new study, led by postdoc Feifei Zhang, of a greatly expanded dolomite section from the Carnic Alps, Austria, marine anoxia is found to have expanded in two pulses separated by ~100,000 years. Global … Read More

New study solves 500 million year old animal breathing paradox

August 12, 2019Publication, Research

Animals breath oxygen, but fossils of some of the earliest animals are found in what appears to be anoxic parts of the oceans. New research, led by Tais W. Dahl in collaboration with researchers from GEUS and Royal Holloway University London, shows that fluctuations in O2 availability at the seafloor allowed benthic animals to invade … Read More

New paper in press: Ocean redox conditions between the Neoproterozoic Snowballs

December 18, 2017Publication, Research, Students and postdocs

A new paper on the redox conditions in the oceans after the Sturtian and before the Marinoan ‘Snowball’ glaciations is now press in Precambrian Research. Our results suggest that oceans remained largely anoxic after the Sturtian glaciation and that something else triggered oxygenation of the Ediacaran oceans after the Marinoan glaciation. This ‘something’ could be due to the way animals affect the global … Read More

Publication: Brief oxygenation event during the Cambrian explosion linked to a reorganization of the marine biogeochemical cycles – might be animal-driven

June 19, 2017Publication

A recent article published in Geochemical Perspectives Letters, we present carbon, sulfur and uranium isotope data from Siberian limestone sections straddling the Cambrian Stage 2–3 boundary (Tommotian-Atdabanian) 521–519 million years ago. We discovered a new type of oceanic event where enhanced marine organic carbon and pyrite burial coincides with a more oxygenated ocean state. The event was relative brief, … Read More

Publication: Molybdenum re-dissolves and re-precipitates in euxinic lake sediments

April 20, 2017Publication

In a paper published in Chemical Geology entitled: “Molybdenum isotope fractionation and speciation in a euxinic lake—Testing ways to discern isotope fractionation processes in a sulfidic setting”, we compare molybdenum isotope and speciation data from lake sediments deposited under euxinic (anoxic and sulfidic) waters. We conclude that the chemical Mo species present in sediments did not … Read More