The progressive oxygenation of the Earth's atmosphere was pivotal to evolution life, but puzzle when and how atmospheric oxygen (O2) first approached modern levels (∼21%) remains unresolved. Redox proxy data indicate deep oceans were oxygenated during 435-392 Ma, appearance fossil charcoal indicates O2 >15-17% by 420-400 Ma. However, existing models have failed predict at this time. Here we show that earliest plants, which colonized land surface from ∼470 Ma onward, responsible for...

Abstract The emergence of oxygenic photosynthesis created a new niche with dramatic potential to transform energy flow through Earth’s biosphere. However, more primitive forms that fix CO 2 into biomass using electrons from reduced species like Fe(II) and H instead water would have competed early biosphere for essential nutrients. Here, we combine experimental microbiology, genomic analyses, Earth system modeling demonstrate competition light nutrients in the surface ocean between...

Abstract The possibility of low but nontrivial atmospheric oxygen (O 2 ) levels during the mid‐Proterozoic (between 1.8 and 0.8 billion years ago, Ga) has important ramifications for understanding Earth's O cycle, evolution complex life evolving climate stability. However, regulatory mechanisms redox fluxes required to stabilize these in face continued biological production remain uncertain. Here, we develop a biogeochemical model C‐N‐P‐O ‐S cycles use it constrain global balance...

Abstract The global silica cycle is an important component of the long-term climate system, yet its controlling factors are largely uncertain due to poorly constrained proxy records. Here we present a ∼70 Myr-long record early Mesozoic biogenic (BSi) flux from radiolarian chert in Japan. Average low-mid-latitude BSi burial superocean Panthalassa ∼90% that modern ocean and relative amplitude varied by ∼20–50% over 100 kyr 30 Myr orbital cycles during Mesozoic. We hypothesize was major sink...

Abstract Carbon is an essential element for life on Earth, and the relative abundances of major carbon species (CO 2 , CO, CH 4 ) in atmosphere exert fundamental controls planetary climate biogeochemistry. Here we employed a theoretical model atmospheric chemistry to investigate diversity CO Earth-like lifeless planets orbiting Sun-like (F-, G-, K-type) stars. We focused conditions formation CO-rich atmosphere, which would be favorable origin life. Results demonstrated that elevated levels...

[1] Wind and wave records obtained from the Kvitebjorn platform (2.3°E, 61.0°N, 190 m deep) in northern North Sea 2003 to 2005 were analyzed. Among 2723 20-min taken during storm conditions, 57 cases included freak waves exceeding twice significant height. Comparisons between various parameters occurrence index did not show any correlation. Thus, situ record was used select days when relatively more or less observed. The classified into freakish non-freakish days, respectively. On Icelandic...

Some atmospheric gases have been proposed as counter indicators to the presence of life on an exoplanet if remotely detectable at sufficient abundance (i.e., antibiosignatures), informing search for biosignatures and potentially fingerprinting uninhabited habitats. However, quantitative extent which putative antibiosignatures could exist in atmospheres inhabited planets is not well understood. The most commonly referenced potential antibiosignature CO, because it represents a source free...

Abstract The advent of oxygenic photosynthesis represents the most prominent biological innovation in evolutionary history Earth. exact timing evolution photoautotrophic bacteria remains elusive, yet these profoundly altered redox state ocean–atmosphere–biosphere system, ultimately causing first major rise atmospheric oxygen (O 2 )—the so‐called Great Oxidation Event (GOE)—during Paleoproterozoic (~2.5–2.2 Ga). However, it unclear how coupled atmosphere–marine biosphere system behaved after...

Iron (Fe) is an essential element for life, and its geochemical cycle intimately linked to the coupled history of life Earth's environment. The accumulated geologic records indicate that ferruginous waters existed in Precambrian oceans not only before first major rise atmospheric O2 levels (Great Oxidation Event; GOE) during Paleoproterozoic, but also rest Proterozoic. However, interactive evolution biogeochemical cycles Fe Archean-Proterozoic remains ambiguous. Here, we develop a model...

Earth's ocean-atmosphere system has undergone a dramatic but protracted increase in oxygen (O2) abundance. This environmental transition ultimately paved the way for rise of multicellular life and provides blueprint how biosphere can transform planetary surface. However, estimates atmospheric levels large intervals history still vary by orders magnitude—foremost middle history. Historically, mid-Proterozoic (1.9–0.8 Ga) are inferred based on kinetics reactions occurring soils or oceans,...

Abstract Earth’s orbital variations on timescales of 10 4 –10 5 years, known as Milankovitch cycles, have played a critical role in pacing climate change and ecosystem dynamics, through glacial and/or monsoon dynamics. However, the climatic biotic consequences these cycles much longer (~ 7 years) remain unclear, due to lack long proxy records with precise age constraints. Here, we show ~ 10-Myr scale early Mesozoic (250–180 Ma) lake-level, desert distribution, biogenic-silica burial flux,...

Abstract The global‐scale oxygenation of Earth's surface represents one the most fundamental chemical transformations in our planet's history. There is empirical and theoretical evidence for at least two distinct stable regimes Earth oxygenation—a “low‐O 2 world” characterized by pervasively anoxic deep ocean waters, a “high‐O with dominantly well‐oxygenated waters represented modern environment. Numerous biogeochemical processes feedbacks control redox state marine system, particularly when...

Abstract The evolution and expansion of land plants brought about one the most dramatic shifts in history Earth system — birth modern soils likely stimulated massive changes marine biogeochemistry climate. Multiple extinctions characterized by widespread anoxia, including Late Devonian mass extinction around 372 million years ago, may have been linked to terrestrial release nutrient phosphorus driven newly-rooted landscapes. Here we use recently published lake records as variable inputs an...

Abstract. A new Earth system model of intermediate complexity – CANOPS-GRB v1.0 is presented for use in quantitatively assessing the dynamics and stability atmospheric oceanic chemistry on Earth-like planets over geologic timescales. The release designed to represent coupled major element cycles C, N, P, O, S, as well global redox budget (GRB) Earth's exogenic (ocean–atmosphere–crust) system, using a process-based approach. This framework provides mechanistic evolution O2 levels timescales...

Abstract Understanding the oceanic phosphate concentration is critical for understanding marine productivity and oxygen evolution throughout Earth history. During Archean, estimates of levels range from scarce to enriched conditions. However, biogeochemical conditions required sustaining high concentrations while retaining an anoxic atmosphere during Archean remain ambiguous. Here, we employ a model cycle determine under which could have been higher than present‐day values after emergence...

Understanding the oceanic phosphate concentration is critical for understanding marine productivity and oxygen evolutions throughout Earth history. During Archean, estimates of levels range from depleted to enriched conditions. However, biogeochemical conditions required sustaining high concentrations while retaining an anoxic atmosphere during Archean remain ambiguous. Here, we employ a model cycle determine under which could have been higher than present-day values after emergence oxygenic...

Abstract The Capitanian stage is characterized by marine anoxia possibly related to the extinction, although global redox structure of ocean has not been constrained. We newly report a nitrogen isotope (δ 15 N) record from paleo‐atoll limestone at top mid‐Panthalassan seamount constrain spatial extent and duration anoxia. δ N value after acid treatment substantially high for ∼5‐Myr up +28‰, highest through Phanerozoic oceans, suggesting that source (nitrate) was enriched in via...