Monthly Archives: June 2014

Volcanoes and photosynthesis

We typically think of volcanoes as destructive, but their eruptions could be feeding tiny photosynthetic organisms that live in the ocean.

Primary productivity (how much photosynthesis occurs) in certain areas of the ocean is iron-limited: even though phytoplankton (photosynthetic microscopic organisms) have plenty of all the other nutrients they need, a shortage of iron limits their growth. Read more

Easy Science: how the Appalachian Mountains formed in four steps

The history of the Appalachians spans over a billion years, with four collisions forming the Appalachian Mountains. The last collision occurred around 300 million years ago. Originally, the chain would have rivaled the Himalayas at over 5 km tall, with some mountains perhaps reaching as high as 9 km. Three hundred million years of erosion slowly whittled the mountains away; today, they average 1 km, with the highest point being 2 km at Mount Mitchell, North Carolina. Read more

Did a starburst cause Earth to get buried in kilometers of snow?

Three times before the Cambrian period (545 mya), the entire earth has been buried in several kilometers of snow -- based on evidence including tropical glacial deposits and the cessation of carbonate production (which prefers to form in warmer waters) -- in a phenomenon known as Snowball Earth. But what causes these drastic glaciations to occur? Read more