Benjamin W. Johnson
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View article: The rise of lichens during the colonization of terrestrial environments
The rise of lichens during the colonization of terrestrial environments Open
The origin of terrestrial life and ecosystems fundamentally changed the biosphere. Lichens, symbiotic fungi-algae partnerships, are crucial to nutrient cycling and carbon fixation today, yet their evolutionary history during the evolution …
View article: Rectus Abdominis Repair Compared to Posterior Wall Mesh Reinforcement in Athletes With Sportsman’s Hernia: A Systematic Review
Rectus Abdominis Repair Compared to Posterior Wall Mesh Reinforcement in Athletes With Sportsman’s Hernia: A Systematic Review Open
Athletic pubalgia is a relatively uncommon injury that is not fully understood. There are few high-level studies comparing treatments of athletic pubalgia, and this investigation seeks to utilize original articles to compare two common tec…
View article: The genesis of metamorphosed Paleoproterozoic massive sulphide occurrences in central Colorado: geological, mineralogical and sulphur isotope constraints
The genesis of metamorphosed Paleoproterozoic massive sulphide occurrences in central Colorado: geological, mineralogical and sulphur isotope constraints Open
Paleoproterozoic massive Cu-Zn±Pb±Au±Ag sulphide deposits metamorphosed to the middle-upper amphibolite facies in central-south Colorado formed in a volcanic arc setting on the edge of the Yavapai crustal province. Previously published U-P…
View article: Dynamic trophic shifts in bacterial and eukaryotic communities during the first 30 years of microbial succession following retreat of an Antarctic glacier
Dynamic trophic shifts in bacterial and eukaryotic communities during the first 30 years of microbial succession following retreat of an Antarctic glacier Open
We examined microbial succession along a glacier forefront in the Antarctic Peninsula representing ∼30 years of deglaciation to contrast bacterial and eukaryotic successional dynamics and abiotic drivers of community assembly using sequenc…
View article: Johnson et al. (2022) code
Johnson et al. (2022) code Open
This is a set of python files that can invert patterns of hydrothermal alteration in crustal systems to reconstruct original fluid oxygen isotope composition. This is a demonstration using four sites from the San Juan Mountains, Colorado, …
View article: Combining Nitrogen Isotopes and Redox Proxies Strengthens Paleoenvironmental Interpretations: Examples From Neoproterozoic Snowball Earth Sediments
Combining Nitrogen Isotopes and Redox Proxies Strengthens Paleoenvironmental Interpretations: Examples From Neoproterozoic Snowball Earth Sediments Open
The history of the nitrogen cycle on Earth is linked to the redox evolution of the surface environment. Many nitrogen cycle fluxes are microbially mediated, and the particular fluxes operating at any given time in an ecosystem depend on th…
View article: The Sedimentary Geochemistry and Paleoenvironments Project
The Sedimentary Geochemistry and Paleoenvironments Project Open
We thank the donors of The American
\nChemical Society Petroleum Research Fund for partial support of
\nSGP website development (61017-ND2). EAS is funded by National
\nScience Foundation grant (NSF) EAR-1922966
View article: The composition and weathering of the continents over geologic time
The composition and weathering of the continents over geologic time Open
The composition of continental crust records the balance between construction by tectonics and destruction by physical and chemical erosion. Quantitative constraints on how igneous addition and chemical weathering have modified the contine…
View article: Creating Reflective Space for Reflective and “Unreflective” Medical Students: Exploring Seminal Moments in a Large-Group Writing Session
Creating Reflective Space for Reflective and “Unreflective” Medical Students: Exploring Seminal Moments in a Large-Group Writing Session Open
Problem Reflection is a critical skill for all physicians, but some busy medical students describe themselves as “unreflective.” The authors sought to provide all third-year medical students at the Medical College of Wisconsin (MCW) with o…
View article: EarthN: A New Earth System Nitrogen Model
EarthN: A New Earth System Nitrogen Model Open
The amount of nitrogen in the atmosphere, oceans, crust, and mantle have important ramifications for Earth's biologic and geologic history. Despite this importance, the history and cycling of nitrogen in the Earth system is poorly constrai…
View article: EarthN: A new Earth System Nitrogen Model
EarthN: A new Earth System Nitrogen Model Open
The amount of nitrogen in the atmosphere, oceans, crust, and mantle have important ramifications for Earth’s biologic and geologic history. Despite this importance, the history and cycling of nitrogen in the Earth system is poorly constrai…
View article: Marine oxygen production and open water supported an active nitrogen cycle during the Marinoan Snowball Earth
Marine oxygen production and open water supported an active nitrogen cycle during the Marinoan Snowball Earth Open
The Neoproterozoic Earth was punctuated by two low-latitude Snowball Earth glaciations. Models permit oceans with either total ice cover or substantial areas of open water. Total ice cover would make an anoxic ocean likely, and would be a …
View article: A secular increase in continental crust nitrogen during the Precambrian
A secular increase in continental crust nitrogen during the Precambrian Open
Recent work indicates the presence of substantial geologic nitrogen\nreservoirs in the mantle and continental crust. Importantly, this geologic\nnitrogen has exchanged between the atmosphere and the solid Earth over time.\nChanges in atmos…
View article: Sedimentary depocenters on Snowball Earth: Case studies from the Sturtian Chuos Formation in northern Namibia
Sedimentary depocenters on Snowball Earth: Case studies from the Sturtian Chuos Formation in northern Namibia Open
Cryogenian synglacial deposits are regionally thin but locally thick, considering glacial duration, but the reasons for local thickening are poorly known. We studied three local thickenings of the Sturtian Chuos Formation in northern Namib…
View article: Supplemental material: Sedimentary depocenters on Snowball Earth: Case studies from the Sturtian Chuos Formation in northern Namibia
Supplemental material: Sedimentary depocenters on Snowball Earth: Case studies from the Sturtian Chuos Formation in northern Namibia Open
Geosphere, June 2017, v. 13, p. 811-837, doi:10.1130/GES01457.1, Supplemental Table S1 - Coordinates of measured columnar sections.
View article: Measurement of geologic nitrogen using mass spectrometry, colorimetry, and a newly adapted fluorometry technique
Measurement of geologic nitrogen using mass spectrometry, colorimetry, and a newly adapted fluorometry technique Open
Long viewed as a mostly noble, atmospheric species, recent work demonstrates that nitrogen in fact cycles throughout the Earth system, including the atmosphere, biosphere, oceans, and solid Earth. Despite this new-found behaviour, more tho…
View article: Nitrogen in the Earth System: planetary budget and cycling during geologic history
Nitrogen in the Earth System: planetary budget and cycling during geologic history Open
The distribution and geologic history of nitrogen on Earth is poorly known. Traditionally thought to be an inert gas, with only a small but important biologic cycle, geochemical investigation highlights that it can also be present in rocks…
View article: Modeling <i>p</i> N <sub>2</sub> through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures
Modeling <i>p</i> N <sub>2</sub> through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures Open
Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size…
View article: Measurement of geologic nitrogen using mass spectrometry, colourimetry, and a newly adapted fluorometry technique
Measurement of geologic nitrogen using mass spectrometry, colourimetry, and a newly adapted fluorometry technique Open
Long viewed as a mostly noble, atmospheric species, recent work demonstrates that nitrogen in fact cycles throughout the Earth system, including the atmosphere, biosphere, oceans, and solid Earth. Despite this new-found behaviour, more tho…
View article: Early extensional detachments in a contractional orogen: coherent, map-scale, submarine slides (mass transport complexes) on the outer slope of an Ediacaran collisional foredeep, eastern Kaoko belt, Namibia
Early extensional detachments in a contractional orogen: coherent, map-scale, submarine slides (mass transport complexes) on the outer slope of an Ediacaran collisional foredeep, eastern Kaoko belt, Namibia Open
The existence of coherent, large-scale, submarine landslides on modern continental margins implies that their apparent rarity in ancient orogenic belts is due to non-recognition. Two map-scale, coherent, pre-orogenic, normal-sense detachme…