Microbial Observatory at the H.J. Andrews LTER

We established a Microbial Observatory at the H.J. Andrews Experimental Forest in 1999. Research at the Andrews Microbial Observatory was supported by two grants from the National Science Foundation. It was a collaborative project among Drs. David Myrold, Peter Bottomley, Kermit Cromack, Jr., Joey Spatafora, and Bruce Caldwell.

The observatory is dedicated to the study of bacteria and fungi central to biogeochemical processes in coniferous forest ecosystems in the Central Cascade Mountains of Oregon. Because nitrogen is the most limiting nutrient to tree growth in this ecosystem, we initially focused on the functional diversity of microorganisms that perform nitrogen cycling processes. Initially, this research effort was devoted to determining the influence of grassland meadow and coniferous vegetation on the functional diversity of key N-cycling microorganisms. Subsequently we examined how ectomycorrhizal mats affected N cycling and associated microorganisms. Although funding for this research is over, we continue to do microbial ecology research at this site as part of the H.J. Andrews LTER.

This project has produced the following publications:
Zeglin, L.H., L.A. Kluber, and D.D. Myrold. 2013. The importance of amino sugar turnover to C and N cycling in organic horizons of old-growth Douglas-fir forest soils colonized by ectomycorrhizal mats. Biogeochem. 112:679-693. (doi: 10.1007/s10533-012-9746-8); Erratum (doi: 10.1007/s10533-012-9777-1)

Zeglin, L.H., and D.D. Myrold. 2013. Fate of decomposed fungal cell wall material in organic horizons of old-growth Douglas-fir forest soils. Soil Sci. Soc. Am. J. 77:489-500. (doi: 10.2136/sssaj2012.0204)

Kageyama, S.A., N.J. Posavatz, S.S. Jones, P.J. Bottomley, K. Cromack, Jr., and D.D. Myrold. 2013. Effects of disturbance scale on microbial communities in the Western Cascades of Oregon. Plant Soil 372:459-471. (doi: 10.1007/s11104-013-1760-7) Phillips, C. L., Kluber, L. A., Martin, J. P., Caldwell, B. A., and Bond, B. J. 2012. Contributions of ectomycorrhizal fungal mats to forest soil respiration. Biogeosciences Discuss. 9:1635-1666. (doi:10.5194/bgd-9-1635-2012)

Trappe, M.J., K. Cromack, Jr., B.A. Caldwell, R.P. Griffiths, and J.M. Trappe. 2012 .Diversity of mat-forming fungi in relation to soil properties, disturbance, and forest ecotype at Crater Lake National Park, Oregon, USA. Diversity. 4:196-223.

Keiluweit, M., J.J. Bougoure, L.H. Zeglin, D.D. Myrold, P.K. Weber, M. Kleber, J. Pett-Ridge, and P.S. Nico. 2012. Nano-scale investigation of the association of microbial nitrogen residues with iron (hydr)oxides in a forest soil O-horizon. Geochim. Cosmochim. Acta 95:213-226.

Kluber, L.A., J.E. Smith, and D.D. Myrold. 2011. Distinctive fungal and bacterial communities are associated with mats formed by ectomycorrhizal fungi. Soil Biol. Biochem. 43:1042-1050.

Kluber, L.A., K.M. Tinnesand, B.A. Caldwell, S.M. Dunham, R.R. Yarwood, P.J. Bottomley, and D.D. Myrold. 2010. Ectomycorrhizal mats alter forest soil biogeochemistry. Soil Biol. Biochem. 42:1607-1613.

Trappe, M.J., K. Cromack, Jr., J.M. Trappe, J. Wilson, M.C. Rasmussen, M.A. Castellano, and S.L. Miller. 2009. Relationships of current and past anthropogenic disturbance to mycorrhizal sporocarp fruiting patterns at Crater Lake National Park, Oregon. Can. J. For. Res. 39:1662-1676.

Trappe, M.J., K. Cromack, Jr., J.M. Trappe, D.B. Perrakis, E. Cazares-Gonzales, M.A. Castellano, and S.L. Miller. 2009. Interactions among prescribed fire, soil attributes, and mycorrhizal community structure at Crater Lake National Park. Fire Ecol. 5:30-50.

Chaer, G.M., D.D. Myrold, and P.J. Bottomley. 2009. A soil quality index based on the equilibrium between soil organic matter and biochemical properties of undisturbed coniferous forest soils of the Pacific Northwest. Soil Biol. Biochem. 41:822-830.

Kageyama, S.A., N. Ritchie Posavatz, K.E. Waterstripe, S.J. Jones, P.J. Bottomley, K. Cromack, Jr. and D.D. Myrold. 2008. Fungal and bacterial communities across meadow/forest transects in the Western Cascades of Oregon. Can. J. For. Res. 38:1053-1060.

Myrold, D.D., and N.J. Ritchie Posavatz. 2007. Potential importance of bacteria and fungi in nitrate assimilation in soil. Soil Biol. Biochem. 39:1737-1743.

Dunham, S.M., K.-H. Larsson, and J.W. Spatafora. 2007. Diversity and community structure of mat-forming ectomycorrhizal fungi in old growth and rotation age Douglas-fir forests of the HJ Andrews Experimental Forest, Oregon, USA. Mycorrhiza 17:633-

Bottomley, P.J., R.R. Yarwood, S.A. Kageyama, K.E. Waterstripe, M.A. Williams, K. Cromack, Jr., and D.D. Myrold. 2006. Responses of soil bacterial and fungal communities to reciprocal transfers of soil between adjacent coniferous forest and meadow vegetation in the Cascade Mountains of Oregon. Plant Soil 289:35-45.

Boyle, S.A., J.J. Rich, P.J. Bottomley, K. Cromack, Jr., and D.D. Myrold. 2006. Reciprocal transfer effects on denitrifying community composition and activity at forest and meadow sites in the Cascade Mountains of Oregon. Soil Biol. Biochem. 38:870-878.

Bottomley, P.J., A.E. Taylor, S.A. Boyle, S.K. McMahon, J.J. Rich, K. Cromack, Jr., and D.D. Myrold. 2004. Responses of nitrification and ammonia-oxidizing bacteria to reciprocal transfers of soil between adjacent coniferous forest and meadow vegetation in the Cascade Mountains of Oregon. Microb. Ecol. 48:500-508.

Rich, J.J., R.S. Heichen, P.J. Bottomley, K. Cromack, Jr., and D.D. Myrold. 2003. Community structure and functioning of denitrifying bacteria from adjacent meadow and forest soils. Appl. Environ. Microbiol. 69:5974-5982.

Mintie, A.T., R.S. Heichen, K. Cromack, Jr., D.D. Myrold, and P.J. Bottomley. 2003. Ammonia-oxidizing bacteria along meadow-to-forest transects in the Oregon Cascade mountains. Appl. Environ. Microbiol. 69:3129-3136.