Advanced chemical analyses reveal that, with the help of smart scavenging bacteria, sulfur and iron compounds accumulated in the timbers of the Swedish warship Vasa during her 333 years on the seabed of the Stockholm harbour. Contact with oxygen, in conjunction with the high humidity of the museum environment, causes these contaminants to produce sulfuric acid, according to a new doctoral thesis in chemistry from Stockholm University.

In forests of the northeastern United States, sulfate and nitrate are the dominant dissolved forms of sulfur and nitrogen in precipitation. In winter, these acidic agents accumulate in the snowpack and are released to groundwater and streams over a short period of time during spring snowmelt.

Sulfur dioxide (SO2) may have played a key role in the climate and geochemistry of early Mars, geoscientists at Harvard University and the Massachusetts Institute of Technology suggest in the Dec. 21 issue of the journal Science.