Join us on Goldschmidt's 2023 Session:

(Bio)chemical sediments as geochemical archives through deep time - Nutrient availability and the co-evolution of Earth's oceans, atmosphere, continents, and life

Bio-essential elements such as P, N, Ni, Mo, Cd, Zn Co, Fe, and other trace metals may have played different but major roles as nutrients over geologic timescales. Their bioavailability is therefore critical in primary production, with significant implications for C and O cycles and, eventually, the evolution of life. However, there is ongoing disagreement about the conflicting role of some nutrients in early Earth's primary production. Despite collective efforts, major questions remain on how and why some elements became essential to building biomolecules, what controlled their provision to living organisms, and how different continental and atmospheric configurations contributed to this development. Aquatic (bio)chemical sediments such as carbonates, lithified microbial mats (microbialites and stromatolites), phosphates, cherts, and banded iron formations are abundant throughout Earth's history and may hold the key to studying the long-term evolution of dissolved bio-essential nutrients and interactions of the biosphere-atmosphere-hydrosphere systems with the geodynamical evolution of the Earth. Geochemical analyses of such archives are critical for extracting information on environmental conditions, geomicrobiological cycles, and post-depositional alteration in modern and ancient systems from natural materials' chemical and isotopic composition. We invite submissions that utilize geochemical and modeling, sedimentological and experimental approaches over a range of natural environments to address these questions and better understand the co-evolution of nutrients and other elemental supplies on Earth's habitats through deep time.

Small review on geochemical tools used in stromatolite research published on public Earth Science Wechat account (in Chinese)

地球早期生命起源及古环境演化一直是地球科学领域内的热点研究问题。大量研究表明叠层石可以很好地记录地球早期生命的演化。1908年，德国地质学家Ernst Louis Kalkowsky （1851-1938）（图1）在他的论文“Oolith und Stromatolith im nord-deutschen Buntsandstein”中首次描述了“叠层石”，并对德国萨克森州地区下三叠统的叠层石构造做了系统的研究（图2），正式开启了叠层石研究的新篇章。

click the image for the original text (in Chinese)

Simplified element cycling in microbial habitats (Figure courtesy S.Hohl)

New publication of our Team on Nature Communications. Steiner et al., ‘Exceptionally preserved early metazoans discovered in Mongolia’

Most animal phyla appeared in the Earth's rock record only during a short period of the Cambrian bio radiation (~540-520 my). Small Shelly Fossils allow us to form conclusions about the sequence of evolutionary events that shaped the Earth's biodiversity, and the existence of stem-group species.

We found exceptionally preserved fossils on two field campaigns in W Mongolia in 2017 and 2019. These astonishing discoveries included the eggs, embryos, and post-embryonic stages of camenellans. Far from being skeletal remains, our newly discovered embryos and post-embryonic stages of camenellans are preserved in soft tissue which was replaced by calcium phosphate during the early sedimentary process of fossilization, conserving them for millions of years.

You can find our publication here

and a blogpost on the fieldwork that leads to the discovery here

New Job at Tongji University

I am happy to announce that I have found a new workplace. In future I will work as an associated researcher/professor at the State Key Laboratory of Marine Geology in the School of Ocean and Earth Science at Tongji University Shanghai in the group of Prof. Dr. Yang Shouye. I am looking forward to work at this exiting workplace and deepen my knowledge of modern marine geochemistry in order to tackle all the questions arising in paleo-marine environments on Earth and beyond. The laboratory is a key lab for studying of marine geochemistry and has excellent reputation and equipment reaching from marine and submarine vessels to open ocean observation platforms and a state of the art geochemical clean lab and mass spectrometry facilities.

more about the lab here

convening session 7f at Goldschmidt 2019

Co-evolving life and environments through deep time

Co-ordinators:
Axel Hofmann (University of Johannesburg)
Aubrey Zerkle (University of St Andrews)
Tais W. Dahl (University of Copenhagen, Natural History Museum)
Benjamin Johnson (University of Colorado at Boulder) 

The Earth surface has seen tremendous changes through time, as recorded in its volcano-sedimentary record. Cooling of the Earth interior, secular changes in tectonic processes and the composition of the lithosphere, the evolution of the atmosphere and hydrosphere, and the appearance and radiation of life all left their imprint to be deciphered with an ever-growing set of geochemical tools. This theme invites session contributions that address the co-evolution of life with Earth’s surface environments over geologic time. It aims to focus on environmental and geological drivers of biospheric evolution, the imprint of life on the Earth system, and associated biogeochemical feedbacks. Prospective topics include, but are not limited to, the origin of life and Hadean habitability, the geochemical histories of the Precambrian atmosphere and oceans, changes in surface processes and their sedimentary products, causes and consequences of rapid biogeochemical change vs stasis in Earth history, microfossil or molecular records of early eukaryotic evolution, the Ediacaran-early Paleozoic transition, and the environmental drivers of mass extinctions and radiations in the Phanerozoic. We seek contributions approaching these questions using a wide range of cross-disciplinary methods and novel analytical techniques, spanning geological, geochemical, biomolecular and modelling approaches.

Convening a session at EGU Vienna 2018

Together with such excellent colleagues from the Precambrian geology field as Graham Shields, Daniel LeHeron and Sebastian Viehmann I am convening a session of biogeochemistry and evolution from the Archean to the Neoproterozoic. The preliminary session abstract is:

Palaeoenvironments of the Precambrian World:

from the Archean via Snowball Earth and beyond

Fundamental key parameters to understand the evolution of life and Earth's habitats involve the interaction between the atmos-, hydros- and biospheres. For instance, the redox- evolution and the geodynamical evolution during Precambrian times played a fundamental role in shaping ancient environments. In this session we invite contributions from combined fields of sedimentology, (bio)geochemistry, numeric modelling, palaeontology and geophysics, ranging in the timeframe from the origin of life until Snowball Earth and beyond. We discuss the (co-)evolution of the atmosphere, biosphere and oceans and also try to understand how much better the Neoproterozoic glaciations are constrained since the last 20 years and what the sedimentary record offers to understand the behaviour of the ancient ice masses, and how it compares to Phanerozoic sedimentary successions.

hope to see you all at EGU this spring

groundbreaking new hypothesis on why life diversified on Earth after the Cambrian explosion

'Refined control of cell stemness allowed animals to evolve in the oxic realm' by Emma U. Hammarlund, Kristoffer von Stedingk and Sven Påhlman

Abstract

Animal diversification on Earth has long been presumed to be associated with the increasing extent of oxic niches. Here, we challenge that view. We start with the fact that hypoxia (<1–3% O2) maintains cellular immaturity (stemness), whereas adult stem cells continuously—and paradoxically—regenerate animal tissue in oxygenated settings. Novel insights from tumour biology illuminate how cell stemness nevertheless can be achieved through the action of oxygen-sensing transcription factors in oxygenated, regenerating tissue. We suggest that these hypoxia-inducible transcription factors provided animals with unprecedented control over cell stemness that allowed them to cope with fluctuating oxygen concentrations. Thus, a refinement of the cellular hypoxia-response machinery enabled cell stemness at oxic conditions and, then, animals to evolve into the oxic realm. This view on the onset of animal diversification is consistent with geological evidence and provides a new perspective on the challenges and evolution of multicellular life.

source: Nature Ecology and Evolution

Human-made aerosols identified as driver in shifting global rainfall patterns

Researchers studied particles released into the atmosphere from the burning of fossil fuels to better predict future climate changes

Source: Sciencedaily