| Summary: | We investigated the productivity of a perennial, Arctic spring-stream. Ivishak Spring has the stable discharge (~131 L/s) and temperature (~4-8 degrees Celsius) typical for springs. It is unusual, however, in having an annual cycle of daylight from 24 hrs/d (summer) to 0 hrs/d (winter). We tested the hypothesis that stored detritus would buffer carbon limitation during winter when gross primary production (GPP) is minimized, resulting in constant rates of community respiration (CR) year-round due to constant temperatures. We used open-channel methods to measure GPP and CR monthly from March 2007 to August 2009. Mean annual GPP was 458 gC/m2. Such a level is typical for temperate desert-streams but was surprising for an Arctic stream. Annual CR (887 gC/m2) was also remarkable. The high metabolism of this stream is explained by an open canopy, moderate year round temperatures, stable bed, and high bryophyte biomass (48 gAFDM/m2). Strong seasonal cycles of GPP were mirrored by CR (r=0.65) indicating the possibility of carbon limitation during winter. This result falsified our hypothesis that CR would be relatively stable year-round due to a detritus buffer and constant temperature. README: Consult the data set README for more information about the physical location of the measurement, instrument description, data collection and processing, data remarks, and data formats. Location Information: Ivishak spring is a tributary of the Ivishak River, a braided river that flows through the Arctic National Wildlife Refuge (ANWR) on the North Slope of the Brooks Range, Alaska.
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