Sentences with phrase «atmospheric oxygen»

How else could one explain how the high level of atmospheric oxygen and vast coal and oil reserves.

At the same time, the plants boosted atmospheric oxygen levels, thus paving the way for the evolution of complex animals.

The results of this comprehensive study suggest that atmospheric oxygen during most of the past 220 million years was considerably lower than today's 21 percent.

Most important, how did the amount of atmospheric oxygen reach its present level?

Could you please educate on atmospheric oxygen; or maybe what I am asking is outside the scope of this site.

When portions of ultraviolet light (UV) strike free atmospheric oxygen it splits the oxygen (O2) into single oxygen (O) molecules.

It burns methane against atmospheric oxygen to produce carbon dioxide and water.

An initial slide in selenium concentrations may have been triggered by a decrease in atmospheric oxygen, which slowed erosion of that element and others from rocks on land, the researchers note.

It shows that the content of atmospheric oxygen has taken several ups and downs.

Lyons notes that the factors controlling the rise of animals are under close scrutiny, including challenges to the long - held view that a major rise in atmospheric oxygen concentrations triggered the event.

Researchers at Princeton University analyzed ice cores collected in Greenland and Antarctica to determine levels of atmospheric oxygen over the last 800,000 years.

Since December 1978, the National Oceanic and Atmospheric Administration's polar - orbiting satellites have measured upwelling microwave radiation from atmospheric oxygen, and Spencer and Christy use this data to calculate the temperature of broad volumes of the atmosphere.

Astronomers could then examine each targeted world for spectroscopic signatures of water vapor, greenhouse gases and «biosignatures» such as atmospheric oxygen, which on Earth is produced by photosynthesizing plants.

The Princeton team analyzed the ice - core data to create a single account of how atmospheric oxygen has changed during the past 800,000 years.

This research also adds important context to other clues about atmospheric oxygen in Mars» past.

The researchers built their history of atmospheric oxygen using measured ratios of oxygen - to - nitrogen found in air trapped in Antarctic ice.

Only during the second marked increase in atmospheric oxygen content 600 million years ago did the deep ocean become fully oxidised, which allowed the oceanic crust to gain the «fingerprint» of high uranium - 238.

Ancient soils like these provide evidence for low atmospheric oxygen levels through much of Earth's history.

The model suggests atmospheric oxygen was likely at around 10 % of present day levels during the two billion years following the Great Oxidation Event, and no lower than 1 % of the oxygen levels we know today.

Lanza added, «It's hard to confirm whether this scenario for Martian atmospheric oxygen actually occurred.

Then, the effect may have snowballed, with the levels of both selenium in seawater and atmospheric oxygen crashing.

While NOAA maintains its own atmospheric CO2 record, it does not track atmospheric oxygen, says Jim Butler, director of the agency's Global Monitoring Division in Boulder, Colorado.

The best idea, from Don Canfield [of the University of Southern Denmark], is that building up a little bit of atmospheric oxygen causes iron pyrite minerals in the continents to oxidize and form sulfate.

The team used the data from charcoal in coal to propose that the development of fire systems through this interval was controlled predominantly by the elevated atmospheric oxygen concentration (p (O2)-RRB- that mass balance models predict prevailed.

«The ups and downs of early atmospheric oxygen.»

The early tetrapods (from the Ancient Greek word meaning «four - footed») were the first vertebrates to tread terra firma, developing lungs to capture atmospheric oxygen and turning fins into legs, but with a life cycle that was still closely tied to aquatic environments.

Abundant atmospheric oxygen has been treated as a so - called biosignature, or a sign of extant life, but this process does not require life.

Co-author Professor Tim Lenton of the University of Exeter adds: «We already think this cycle was key to helping stabilise atmospheric oxygen during the Phanerozoic (the last 542 million years)-- and that oxygen stability is a good thing for the evolution of plants and animals.

«The only ways on Earth that we know how to make these manganese materials involve atmospheric oxygen or microbes,» said Nina Lanza, a planetary scientist at Los Alamos National Laboratory in New Mexico.

Only after atmospheric oxygen was formed did uranium become oxidised to its mobile hexavalent uranium (VI).

Potential explanations have included rising levels of atmospheric oxygen because of photosynthesis, allowing for the development of more complex animals; the rise in carnivorous species and new predatory tactics, such as the flat and segmented, armor - crushing creatures known as anomalocaridids; and the breakup of the supercontinent Rodinia, which may have created new ecological niches and isolated populations as the continents drifted apart.

Michielsen's clothes are coated in a nano thin layer of light - absorbing chemical dyes that grab atmospheric oxygen and convert it into toxic, highly oxidizing forms.

Zinc - air batteries combine atmospheric oxygen and zinc metal in a liquid alkaline electrolyte to generate electricity with a byproduct of zinc oxide.

The two zones can tell us about past atmospheric oxygen levels and the ancient Martian climate.

For the Cretaceous period (65 — 145 million years ago), for example, up to 30 percent atmospheric oxygen has been suggested previously.

«During photosynthesis plants bind atmospheric carbon, whose isotopic composition is preserved in resins over millions of years, and from this, we can infer atmospheric oxygen concentrations,» explains Ralf Tappert.

Two billion years ago, around the time atmospheric oxygen levels were rising, one cell engulfed another, and instead of becoming lunch, the ingestee became an Earth - changer and, eventually, a vital part of you: mitochondria.These microscopic cell inhabitants / engines allowed their host cell to suddenly begin to burn oxygen when digesting their food, an energy source that vastly expanded the amount of energy they could harvest from a given morsel of food.

Along with weather and geologic processes on Earth removed carbon dioxide from the atmosphere, the expanding success of photosynthetic microbes eventually created so much atmospheric oxygen and depleted methane and carbon dioxide levels to such an extent that the greenhouse effect may have become negligible around Year 2.1 billion, chilling the young Earth (Gabrielle Walker, New Scientist, 1999); and Evans and Kirschvink, 1997).

Such giant creatures are often attributed to one of three factors: 1) supercharged development by climbing atmospheric oxygen levels; or 2) an evolutionary arms race gone wild in parallel with its trilobite prey; or, 3) a paucity of vertebrate predator competition, all of which are plausible in Paleozoic paleobiology.

One group of researchers favors «stratification» as a cause — the tendency of climate warming of the upper ocean to restrict seasonal overturning and reduce the supply of new atmospheric oxygen.

So as we burn fossil fuels, we will also deplete atmospheric oxygen.

Cold water at the poles dissolves atmospheric oxygen, cools even more, and sinks to the bottom, slowly moving to the equator, carrying the dissolved oxygen.

They have a particular interest in the jumps in the level of atmospheric oxygen seen about 2.4 billion years ago and 600m years ago.

We also know that phytoplankton, the base of the oceanic food chain, significantly effects atmospheric oxygen and carbon dioxide levels, despite their decline.