Related Experiment Video
Updated: Jan 27, 2026
07:17
Production and Detection of Reactive Oxygen Species ROS in Cancers
Published on: November 21, 2011
71.0K
Limited oxygen production in the Mesoarchean ocean
Frantz Ossa Ossa1,2, Axel Hofmann2, Jorge E Spangenberg3
1Department of Geosciences, University of Tuebingen, 72074 Tuebingen, Germany; frantz.ossaossa@gmail.com.
Summary
Mesoarchean oceans show evidence of localized oxygen oases, but lacked a widespread aerobic nitrogen cycle. Nutrient limitations, not nitrogen, likely restricted oxygen-producing life during this early Earth period.
Area of Science:
- Geochemistry
- Paleoceanography
- Early Earth conditions
Background:
- Archean Eon characterized by anoxic surface conditions and anaerobic bioessential element cycling.
- Mesoarchean (3.2-2.8 Ga) ocean oxygenation is debated, contrasting with Neoarchean 'oxygen oases'.
Purpose of the Study:
- Investigate Mesoarchean ocean oxygenation and nitrogen cycling.
- Determine the extent and causes of potential oxygen oases during the Mesoarchean.
Main Methods:
- Analysis of nitrogen (δ15N) and carbon (δ13C) isotope values in Mesoarchean shales.
- Assessment of local seawater redox conditions and manganese precipitation.
- Evaluation of iron and manganese redox systematics.
Main Results:
- Evidence for localized oxygen oases in the Mesoarchean ocean, indicated by iron and manganese redox data.
- Nitrogen isotope data suggest a molybdenum-dependent diazotrophic biosphere, with no significant aerobic nitrogen cycle.
- Dissolved O2 levels were likely too low or spatially limited to form a substantial nitrate reservoir.
Conclusions:
- Mesoarchean oxygen oases existed but did not support a widespread aerobic nitrogen cycle.
- Nutrient limitations, possibly phosphorus, suppressed oxygen-producing organisms and limited oxygenation expansion.
- Contrasts with Neoarchean oxygenation, highlighting different environmental controls on early Earth life.
Related Concept Videos
02:27Limiting Reactant
69.9K
The relative amounts of reactants and products represented in a balanced chemical equation are often referred to as stoichiometric amounts. However, in reality, the reactants are not always present in the stoichiometric amounts indicated by the balanced equation.
69.9K
01:29The Number e as a Limit
75
The number e is a fundamental constant in calculus, playing a central role in describing continuous change, particularly exponential growth. It is most naturally defined through its relationship with the natural logarithm, which is the inverse of the exponential function with base e. This relationship allows e to be characterized using basic principles of differentiation rather than as an arbitrary numerical constant.A key property of the natural logarithm function, ln x, is that its derivative...
75
01:14Central Limit Theorem
20.0K
The central limit theorem, abbreviated as clt, is one of the most powerful and useful ideas in all of statistics. The central limit theorem for sample means says that if you repeatedly draw samples of a given size and calculate their means, and create a histogram of those means, then the resulting histogram will tend to have an approximate normal bell shape. In other words, as sample sizes increase, the distribution of means follows the normal distribution more closely.
The sample size, n, that...
The sample size, n, that...
20.0K
01:38Limits to Natural Selection
34.4K
Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.
34.4K
01:25Limits on Trigonometric Functions
59
Limits on Trigonometric FunctionsThe limits of trigonometric functions play a fundamental role in calculus, particularly in defining derivatives. One of the most important results is:which is important for differentiating trigonometric functions and is widely applied in mathematical analysis and physics.Geometric IntuitionA common approach to proving this result involves analyzing a sector of a unit circle with an angle subtended at the center. Since the arc length is numerically equal to the...
59
01:28Accuracy, limits, and approximation
1.3K
Accuracy, limits, and approximations are common in many fields, especially in engineering calculations. These concepts are imperative for ensuring that a given value is as close as possible to its true value.
Accuracy is defined as the closeness of the measured value to the true or actual value. In engineering mechanics, repeated measurements are taken during theoretical or experimental analyses to ensure that the result is precise and accurate.
The accuracy of any solution is based on the...
Accuracy is defined as the closeness of the measured value to the true or actual value. In engineering mechanics, repeated measurements are taken during theoretical or experimental analyses to ensure that the result is precise and accurate.
The accuracy of any solution is based on the...
1.3K