Editorial
The Increasing Vigor of Earth's Terrestrial Plants: As the air's CO2 content continues to rise, so also is the planet's terrestrial vegetation becoming ever more productive.

Medieval Warm Period Record of the Week
This issue's Medieval Warm Period Record of the Week comes from the European Margin of the North Atlantic.

Subject Index Summary
Ocean Acidification (Effects on Marine Plants: Phytoplankton, Mixtures of All Types): How do marine phytoplanktonic communities characteristic of the real world respond to increases in the CO2 concentration of the air that is in intimate contact with their watery environments?

Journal Reviews
Characterizing the Mayan Terminal Classic Period: It was a truly trying -- and drying -- time.

The Medieval Warm Period and Little Ice Age in Arid Central Asia: What was learned about the relationship between temperature and precipitation during the two periods?

Effects of Ocean Warming and Acidification on Jellyfish: Just how devastating is the combination?

Effects of Elevated CO2 on an Economically Important Seaweed: Even in seawater where photosynthetic rates of the alga are essentially saturated, elevated CO2 still boost its biomass production.

A Largely Unappreciated Effect of Elevated Atmospheric CO2 on Coastal Seawater Nitrogen Content: What is it? What is its magnitude? And how does it impact both ocean biology and global climate?