Crenshaw, C. L. Virginia Polytechnic Institute and State University,
Valett, H. M. Virginia Polytechnic Institute and State University,
Tank, J. L. University of Illinois,

We studied effects of introduced coarse particulate organic matter (CPOM) in hyporheic and stream bank (i.e. parafluvial) habitats to investigate the hypothesis that CPOM and biofilms of interstitial sediments are important sources of food for groundwater invertebrates. Little is known about biofilm development and organic matter content of parafluvial and hyporheic zones. Nine pairs of rock-filled baskets were buried 15 cm below the surface in Gallina Creek, a first order montane stream in New Mexico. Three pairs were buried in the parafluvial zone and six were buried in the hyporheic zone. One basket from each pair was supplemented with six oak veneer strips (3"X5") to simulate buried CPOM. Baskets were incubated for six weeks and access tubes allowed for periodic sampling of interstitial water within baskets. Wood veneers in both hyporheic and parafluvial baskets were colonized by fungi, but fungal biomass was significantly lower in the parafluvial than in the hyporhiec zone (P=.028), and may have been a result of dissolved oxygen concentrations being significantly lower (P=.0001) in the parafluvial zone. Invertebrate abundance was significantly higher (P=.032) in baskets supplemented with wood. These data suggest a strong relationship between buried CPOM, microbial biofilms, and distribution and abundance of interstitial invertebrates.
Day: Wednesday, Feb. 3
Time: 02:00 - 02:15pm
Location: Eldorado Hotel
Code: CS64WE0200E