Taxonomy term


Comment: Could NASA find evidence of extraterrestrial life by 2050?

Two upcoming missions will provide the first systematic approach to searching the atmospheres of exoplanets for signs of life — and they could find it in the next several decades.

04 Jun 2018

A flammable planet: Fire finds its place in Earth history

For hundreds of millions of years, wildfires have shaped the planet, from the plants, animals and ecosystems around us to the air we breathe. Yet scientists are only beginning to understand the planet’s fiery past. 
16 Jan 2018

Ocean oxygen levels control seafloor carbon burial

Residual organic carbon from dead marine phytoplankton and other oceanic life can follow two pathways: It can be deeply buried in seafloor sediments or it can be oxidized, either in the water column or in shallow sediment layers. The balance between these two processes and the extent of organic carbon burial over time are crucial in the global carbon cycle, but a complete understanding of the factors and rates controlling organic carbon burial versus oxidation in the oceans has been lacking. In a recent study in Geology, scientists improved on an approach to quantify organic carbon oxidation and provided a glimpse of marine organic carbon burial in the Precambrian, when the oceans were anoxic and Earth’s atmosphere was in the early stages of oxygenation.
05 Dec 2015

Nutrient runoff feeding Baltic Sea dead zone

Low-oxygen, or hypoxic, deep waters now extend over an area of about 60,000 square kilometers in the Baltic Sea, a tenfold increase compared to 115 years ago, according to a recent study published in Proceedings of the National Academy of Sciences. The hypoxic zone has fluctuated substantially in that period, but much of the expansion has occurred in recent decades as a result of large inputs of nutrients like nitrogen and phosphorus from human activities such as agriculture, reported Jacob Carstensen of Aarhus University in Denmark and colleagues.

03 Sep 2014

Benchmarks: Sept. 26, 1912: Birth of Preston Cloud, geologist who deciphered banded iron formations

Banded iron formations (BIFs) represent some of the earliest, and most controversial, evidence that the early Earth was devoid of oxygen. These deposits were recognized for their economic value in the mid-1800s, but it wasn’t until the late 1960s when Preston Cloud focused his intellect on  the origins of (BIFs).

26 Sep 2013

Trial by Fire

What makes a fire burn? In addition to fuel (such as wood or paper) and heat, fires need oxygen. If there isn’t enough oxygen in the atmosphere, combustion simply won’t happen.

That was as true hundreds of millions of years ago as it is today. So wildfires, scientists say, can provide a unique way to estimate how much oxygen was in Earth’s atmosphere throughout its history.

04 Sep 2008