+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Seasonal protein dynamics in Alaskan arctic tundra soils



Seasonal protein dynamics in Alaskan arctic tundra soils



Soil biology and biochemistry 37(8): 1469-1475



In the arctic tundra of Alaska, plant growth is limited by N supply, especially in tussock tundra. Because proteins are the predominant form of soil organic N, proteolysis is considered to be the rate-limiting step in both the release of amino acids and in N mineralization. To help understand the controls on N availability in tundra soils, and to determine whether proteolysis is controlled by enzyme activity or by substrate availability, we measured soil protein concentrations, and proteolysis rates with and without added protein, every 1-2 weeks through the summer of 2000 and twice in the summer of 2001. Protease activity with added protein ('potential') was higher than without added protein ('actual'). However, differences between the two tended to be driven by relatively brief peaks in potential protease activity. In fact, actual and potential rates were usually similar, suggesting that much of the time proteolysis was not limited by substrate availability, but rather by enzyme activity. Our data suggest that protease activity was actually only substrate limited at the times when it was highest. Potential rates peaked at the same times that soluble proteins were also high. These increases in protease activity and soluble protein concentrations occurred when soil amino acid and NH4(+) concentrations were at their lowest, drawn down by the seasonal peaks in root growth. The fact that the peaks in protease activity coincided with the peak in soil amino acid and NH4(+) demand strongly suggests that proteolysis was stimulated by high soil amino acid demand, and resulted in increases in soluble protein concentrations caused by the solubilization of larger proteins.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 004311906

Download citation: RISBibTeXText

DOI: 10.1016/j.soilbio.2005.01.005


Related references

The Seasonal Dynamics of Amino Acids and Other Nutrients in Alaskan Arctic Tundra Soils. Biogeochemistry 73(2): 359-380, 2005

The seasonal dynamics of amino acids and other nutrients in Alaskan Arctic tundra soils. Biogeochemistry 73(2): 359-380, 2005

Arctic Soils and Permafrost: Special Issue in Memory of Kaye R. Everett || Hydrology of a Tundra Wetland Complex on the Alaskan Arctic Coastal Plain, U.S.A. Arctic and Alpine Research 28(3): 311-317, 1996

CO2 exchange in the Alaskan arctic tundra: seasonal changes in the rate of photosynthesis of four species. Photosynthetica 9(4): 376-390, 1975

Carbon di oxide exchange in the alaskan usa arctic tundra seasonal changes in the rate of photosynthesis of 4 species. Photosynthetica 9(4): 376-390, 1975

Patterns of Vegetation and Herbivory in Arctic Tundra: Results from the Research on Arctic Tundra Environments (RATE) Program || Some Effects of Mammalian Herbivores and Fertilization on Tundra Soils and Vegetation. Arctic and Alpine Research 12(4): 565-578, 1980

Patterns of Vegetation and Herbivory in Arctic Tundra: Results from the Research on Arctic Tundra Environments (RATE) Program || Distribution and Variability of Soils near Atkasook, Alaska. Arctic and Alpine Research 12(4): 433-446, 1980

Seasonal changes in ammonification and its relationship to bacterial biomass in arctic tundra soils. Abstracts of the Annual Meeting of the American Society for Microbiology 74:, 1974

Seasonal variation in enzyme activities and temperature sensitivities in Arctic tundra soils. Global Change Biology 15(7): 1631-1639, 2009

Seasonal dynamics of leaf- and root-derived C in arctic tundra mesocosms. Soil biology and biochemistry 36(4): 655-666, 2004

Proceedings of the 25th anniversary celebration of the naval arctic research laboratory on alaskan arctic tundra fairbanks alaska august 14 1972. Arctic Institute of North America Technical Paper 25: 7-224, 1973

Controls over intra-seasonal dynamics of AVHRR NDVI for the Arctic tundra in northern Alaska. International Journal of Remote Sensing 25(9): 1547-1564, 2004

Seasonal changes in hydrology, energy balance and chemistry in the active layers of Arctic tundra soils in Taymyr Peninsula, Russia. Pages 299-306 1999, 1999

Nitrogen dynamics in arctic tundra soils of varying age: differential responses to fertilization and warming. Oecologia 173(4): 1575-1586, 2013

Chloroform emissions from the Alaskan Arctic tundra. Geophysical Research Letters 35.21, 2008