@article {KNZ00703, title = {Responses of soil microarthropods to changes in soil water availability in tallgrass prairie}, journal = {Biology and Fertility of Soils}, volume = {29}, year = {1999}, pages = {207 -217}, abstract = {Changes in precipitation and soil water availability predicted to accompany global climate change would impact grasslands, where many ecosystem processes are influenced by water availability. Soil biota, including microarthropods, also are affected by soil water content, although little is known about how climate change might affect their abundance and distribution. The goal of this study was to examine soil microarthropod responses to altered soil water availability in tallgrass prairie ecosystems. Two separate experiments were done. The first utilized control and irrigated plots along a topographic gradient to examine the effects of soil water content on microarthropod densities. Microarthropods, mainly Acari, were significantly less abundant in irrigated plots and were generally less abundant at the wetter lowland sites. The second study utilized reciprocal core transplants across an east-west regional precipitation gradient. Large, intact cores were transplanted between a more mesic tallgrass site (Konza Prairie) and a more arid mixed-grass site (Hays) to determine the effects of different soil water regimes on microarthropod abundance and vertical distribution. Data from non-transplanted cores indicated greater total microarthropod densities at the drier Hays site, relative to the wetter Konza Prairie site. Data from the transplanted cores indicated significant effects of location on Acari densities in cores originating from Hays, with higher densities in cores remaining at Hays, relative to those transplanted to Konza. Acari densities in cores originating from Konza were not affected by location; however, oribatid mite densities generally were greater in cores remaining at Konza Prairie. These results confirm the importance of soil water content in affecting microarthropod densities and distributions in grasslands, and suggest complex, non-linear responses to changes in water availability.}, keywords = {LTER-KNZ, Acari, Climate change, Grassland soils, Soil microarthropods, Soil water content}, doi = {10.1007/s003740050546}, author = {O{\textquoteright}Lear, H.E. and John M. Blair} } @article {KNZ00673, title = {Variations in microbial activity due to fluctuations in soil water content at the water table interface}, journal = {Journal of Environmental Science and Health}, volume = {34}, year = {1999}, pages = {479 -505}, abstract = {A soil column experiment was designed to investigate the response of an indigenous microbial population to a vertically fluctuating water table. A subsurface environment with a transitional zone was simulated. The water table in the soil columns was raised and lowered, and compared to columns under static conditions. Carbon dioxide and oxygen concentrations were measured. Peaks of CO2 occurred in the fluctuating columns immediately following a rise in the water table. Dissolved O2 in the fluctuating columns was consistently lower throughout the experiment, but these lower concentrations were exaggerated immediately following a rise in the water table. Values for total organic carbon in the pore water were slightly lower in the fluctuating columns. The results of this soil column study indicate that vertical fluctuation of the water table can enhance microbial activity of indigenous soil microbial populations. This increase in microbial activity suggests an increased rate of available carbon under these conditions.}, keywords = {LTER-KNZ, bioremediation, microbial activity, soil interface, soil texture, Soil water content, subsurface sediments}, doi = {10.1080/10934529909376849}, author = {Banks, M.K. and Clennan, C. and W. K. Dodds and C. W. Rice} }