The issue focused on medical marijuana research and studies as medical marijuana became legal in Colorado and Washington state in 2012.


Read MoreStory highlights Scientists study ocean chemistry and trends in climate change

Previous studies looked at carbon dioxide levels and ocean chemistry

Now scientists study biological chemistry and trends in climate change

Global warming could boost biological productivity and biological productivity could rise by 10 to 30% by 2100, scientists report in the journal Nature Climate Change

Their research focused on ocean chemistry and trends in climate