Responses of a beaded Arctic stream to short--term N and P fertilization. Freshwater Biology 50:277--290

• Main Authors: Jonathan P. Benstead, Linda A. Deegan, Bruce J Peterson, Alexander D. Huryn, William B. Bowden, Keller Suberkropp, Karen M. Buzby, Adrian C. Green, Jay A. Vacca
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: Arctic; Tundra
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.570.9287; http://bama.ua.edu/~jbenstead/Publications_files/FB Hershey copy.pdf

1. Oligotrophic Arctic streams are likely to be sensitive to changes in hydrology and nutrient inputs predicted to occur as a consequence of future climate and land use change. To investigate the potential consequences of nutrient enrichment for low-order Arctic streams, we added ammonium-N and phosphorous to a second-order beaded, tundra stream on Alaska’s north slope. We measured responses in nutrient chemistry, chlorophyll a standing crop, and in the breakdown and macroinvertebrate colonisation of leaf litter over a 38-day summer period. 2. During the addition, nutrient concentrations immediately downstream of the dripper averaged 6.4 lM ammonium-N and 0.45 lM soluble reactive P. Concentrations upstream of the dripper averaged 0.54 lM ammonium-N and 0.03 lM soluble reactive P. Uptake of both nutrients was rapid. Concentrations were reduced on average to 28 % (ammonium-N) and 15 % (inorganic P) of maximum values within 1500 m. Standing crops of chlorophyll a on standardised samplers were significantly higher by the end of the experiment. Breakdown rates of senescent willow (Salix sp.) and sedge (Carex sp.) litter and associated fungal biomass were also significantly increased by nutrient addition.