Journal of Geophysical Research: Biogeosciences

Cover image for Vol. 120 Issue 8

Impact Factor: 3.426

ISI Journal Citation Reports © Ranking: 2014: 19/175 (Geosciences Multidisciplinary)

Online ISSN: 2169-8961

Associated Title(s): Journal of Geophysical Research

Measuring the biogeochemical response to pulses of water

Hydrologic pulses, temporary increases in water inputs such as bouts of precipitation, can affect biogeochemical processes in ecosystems by providing water and nutrient resources, but ecosystem responses to the water vary. Harms and Grimm (2012) conducted experiments to determine how hydrologic pulses and existing moisture conditions interact to affect the biogeochemistry of desert floodplains. At their study site in the floodplains of the San Pedro River in Arizona, during dry and monsoon seasons the researchers experimentally added pulses of water, then measured the emission of several trace gases that are indicators of biological processes. They found that the size of the added hydrologic pulse strongly interacted with existing soil moisture conditions in determining emissions of some trace gases. For instance, following dry conditions, pulses of water stimulated carbon dioxide, methane, and nitric oxide emissions, with larger water pulses stimulating more emissions. However, when soil was already wet, the addition of water pulses had less effect on the emission of these gases.

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