Laura filling here sample jars with the water samples that were collected at various depths up the water column. After filling her sample bottles she adds NaOH (sodium hydroxide) which will "poison" any of the living creatures, such as bacteria, that might be present. She does this because she will be analyzing the water samples for methane. Biological activity within the bottles could produce methane that was not there when the sample was originally collected. Image courtesy of Hudson Canyon Cruise 2002, NOAA/OER.
