Temperature, discharge and light data for Ivishak Hot Spring, Alaska

Ivishak Spring has the stable discharge (~131 L/s) and temperature (~4-8 deg C) typical for springs. It is unusual, however, in having an annual cycle of daylight from 24 hrs/d (summer) to 0 hrs/d (winter).

It was tested from 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. Open-channel methods were used to measure GPP and CR monthly from March 2007 to August 2009. Mean annual GPP was 458 gC/m2.