This NBC Learn video, one in a 6-part "Cheeseburger Chemistry" series, examines the role of salty brine, fermentation, lactic acid and pH in the process of pickling food to preserve it.

As higher amounts of carbon dioxide become absorbed by the oceans, some marine organisms are finding it's a struggle to adjust. "Changing Planet" is produced in partnership with the National Science Foundation.

This NBC Learn video "profiles" the H2O molecule -- its structure, polarity, cohesive and adhesive properties, and water's properties as a "universal" solvent.

Chart produced by the Environmental Protection Agency of the pH scale from 0 to 14, Acidic to Basic, with examples of substances that have each pH value, and an indication of environmental effects of selected pH levels on fish and insects. Source: EPA

"American Business" profile of woman and her colleague, who, after being laid off from their jobs on Wall Street, went to "pickle school," and started a successful and growing pickle company, Miss Jenny's Pickles. Originally aired on "Your Business" on MSNBC.

This 2010 "Scientific American" article reports on the unprecedented rise in the acidity of the world's seawater, due to ocean absorption of CO2 emissions; higher acidification threatens the marine food chain. Source: Scientific American, February 22, 2010

This 2009 "Scientific American" article reports on new technologies to desalinate ocean water into drinking water more efficiently and at lower cost, in response to ever-growing global demand for potable water, and limited freshwater supply. Source: Scientific American, March 19, 2009

11 words, from "conservative" to "reservoir" -- derived from the Latin root "servo," meaning "to save," "to keep," "to guard," "to watch over" -- are shown in this NBC animation.

Food safety officials warn consumers not to eat fresh spinach, after spinach contaminated with E. coli bacteria causes illnesses in 19 states. Mass production and cross-country transport make it hard to trace the contamination source.

This 2006 "Scientific American" article explains several ways in which salt (usually sodium chloride) and sugar (usually sucrose), inhibit microbial growth to "cure" and preserve foods. Scientific American, February 21, 2006

In 2004, NASA's Opportunity rover finds evidence that there were once large quantities of water on Mars. Scientists theorize that salt crystals may have formed from the water and later dissolved.

Timeline of the History of Pickles, from 2400 BC in Mesopotamia through the First Annual New York City International Pickle Day in 2001. Source: New York Food Museum, Dana Terebelski and Nancy Ralph

The people and wildlife of the Amazon in Brazil coexist in a rainforest that many call the "lungs of the world."

Recipe for Green Sour Pickles, from "The Boston Cooking-School Magazine of Culinary Science and Domestic Economics." (Published between June of 1900 and May of 1901)