Ocean Chemistry

Trichodesmium strain H9-4 isolated from a site near Station ALOHA of the Hawaii Ocean Time Series study. Cyanobacteria such as Trichodesmium fix atmospheric nitrogen into ammonia and are an important source of new nitrogen of the ocean. Here a large number of heterotrophic bacteria are seen to be localized around the filament, suggesting they metabolize organic matter released by the cyanobacterium. (Photo by Annette Hynes, Woods Hole Oceanographic Institution)

Biogeochemistry

As part of the global carbon cycle, underwater volcanoes emit between 66 to 97 million tonnes of CO2 per year. However, this is balanced by the carbon sink provided by newly formed ocean floor lava. (NOAA)

Carbon Cycle

Justin Ries, a former postdoctoral scholar at WHOI, and colleagues Anne Cohen and Dan McCorkle grew 18 species of shell-building marine organisms in tanks under air containing different concentrations of carbon dioxide—from the level in today's atmosphere, to higher levels predicted for the future, to extremely high levels. Not all species responded the same way to higher carbon dioxide levels in seawater and the higher acidity it generates. Some species, such as conchs (Strombus alatus), deteriorated, but surprisingly, some thrived. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)

Ocean Acidification