Grain size and depth constraints on microbial variability in coastal plain subsurface sediments
- .
- BATTELLE (PACIFIC NW LAB)
We have examined the effects of sediment grain size and depth on the abundance and activity of aerobic bacteria at two coastal plain sites in Virginia. Samples were collected at centimeter intervals as well as meter intervals because fine-scale sampling can be essential to assess microbial variability. At the Oyster site, grain size varied from 0.12 to 0.25 mm below 1.5 m depth and did not correlate with either bacterial abundance or activity. Perhaps due to the fairly uniform grain size at this site, variations in bacterial numbers were less than fivefold between replicate samples of 0,1 to 100 g and generally less than 15-fold among closely spaced intervals (~5 cm). At the Abbott Pit site, grain size was about threefold greater (0.50 ± 0.17mm) in an interval of 4.35 to 5.0m below land surface than grain size in the surrounding sediments. In the same interval, bacterial abundance increased by 11-fold and activity increased by 217-fold relative to the surrounding sediments. Overall, grain size correlated significantly with bacterial abundance and activity below the soil zone at the Abbott Pit site. This suggests that changes in grain size, even at the centimeter scale, could have a predominant effect on microbial variability in sandy aquifers of the coastal plain. Besides grain size, depth correlated significantly with total organic carbon and bacterial abundance and activity at both sites, suggesting that depth is also an important factor controlling microbial variability in the subsurface environments.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1557646
- Report Number(s):
- PNNL-SA-31654
- Journal Information:
- Geomicrobiology Journal, Vol. 15, Issue 3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Environmental factors affecting distribution and abundance of bacteria, fungi and protozoa in subsurface sediments of the Upper Atlantic Coastal Plain, USA
Change of Collision Efficiency with Distance in Bacterial Transport Experiements