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Biology Department Fields: Aquatic and Ecosystem Ecology |
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Email: wsobczak@holycross.edu
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Teaching
Fall Semester:
- Freshwater Ecology (Biology 233)
Spring Semester:
- Ecosystems Ecology (Biology 331)
Environmental Biology (Biology 114)
Research
My present research follows three paths:
1. Coupling existing forest-atmosphere hydrology and carbon flux research with new stream biogeochemistry research
Aquatic ecologists have recently argued that carbon and nitrogen cycles need to be studied more closely across transitional zones from terrestrial to aquatic ecosystems. At the same time, an understanding is emerging from terrestrial studies that the net metabolism of many ecosystems is often very close to being balanced on annual and decadal time scales, therefore the fluvial loss of materials to streams may be an important, yet overlooked term in estimates of organic matter and nutrient stocks. In addition, there is a growing understanding that nitrogen loss in nitrogen-limited forests can be dominated by dissolved organic nitrogen. The overarching objective of the research is to explore linkages between forest and stream ecosystem fluxes of energy and nutrients at times scales spanning minutes to decades. Over the past couple of years we have installed stream gages and developed novel aquatic probe systems to investigate the coupling of terrestrial and aquatic biogeochemical cycles at short time scales. My research is centered on hypotheses that have emerged from this new data acquisition and represents the start of a long-term plan to study the interactions of coupled forest and stream biogeochemical cycles at the Harvard Forest LTER.
About Harvard Forest: Since 1907 research and education have been the mission of the Harvard Forest (), one of the oldest and most intensively studied forests in North America. From a center comprised of 3000 acres of land, research facilities, and the Fisher Museum the scientists, students, and collaborators at the Forest explore topics ranging from conservation and environmental change to land-use history and the ways in which physical, biological and human systems interact to change our earth.
2. Understanding how organic matter in melting permafrost impacts coupled aquatic ecosystems and is transferred to the atmosphere and Arctic Ocean
The Polaris Project includes a field course and research experience for undergraduate students in the Siberian Arctic, several new arctic-focused undergraduate courses taught by project scientists at their home institutions, the opportunity for those scientists to initiate research programs in the Siberian Arctic, and a wide range of student science projects and outreach activities. The guiding scientific theme is the transport and transformations of carbon and nutrients as they move with water from terrestrial uplands to the Arctic Ocean, a central issue as scientists struggle to understand the changing Arctic. There is increasing evidence that inland freshwater ecosystems play a significant role in the global carbon cycle due to the metabolism of terrestrial-derived organic matter as it moves in fluvial networks from land to sea. Recent research suggests that Arctic watersheds may increasingly augment the global role of freshwater ecosystems in the flux of terrestrial carbon to the atmosphere and ocean as a result of global warming.
About the Polaris Project: The Polaris Project () includes a field course and research experience for undergraduate students in the Siberian Arctic, several new arctic-focused undergraduate courses taught by project scientists at their home institutions, the opportunity for those scientists to initiate research programs in the Siberian Arctic, and a wide range of student science projects and outreach activities. The guiding scientific theme is the transport and transformations of carbon and nutrients as they move with water from terrestrial uplands to the Arctic Ocean, a central issue as scientists struggle to understand the changing Arctic.
3. Urban river ecology and biogeochemistry: Worcester’s Blackstone River and the urban stream syndrome
Urban aquatic and terrestrial ecology are rapidly growing fields in the disciplines of freshwater ecology and general ecology. Researchers have now established a robust conceptual model for studying urban rivers: the “urban stream syndrome”. Worcester’s Blackstone River provides a training ground for students interested in the chemistry, ecology, hydrology, and geomorphology of urban rivers and their impact on diverse downstream ecosystems. Student research can be connected with the efforts of non-profit groups eager to promote restoration programs that help improve the river’s health (see Blackstone River Coalition website).
About the Blackstone River Coalition: The Blackstone River Coalition (BRC, ) is a group of organizations representing thousands of individuals whose interest is the regeneration of the Blackstone River. One of the Coalition's goals is to reinvigorate the "grassroots" and "can do!" spirit of the original "ZAP the Blackstone" project. That event, which took place on September 9, 1972 along the Blackstone River, consisted of 10,000 volunteers who took it upon themselves to remove more than 10,000 tons of debris from the banks and water of the Blackstone River. It is with the same spirit and vigor that the BRC continues the work necessary to "Make the River Clean by 2015”.
Publications (most available as pdf)
Raymond, P. A., J. E. Saiers, and W. V. Sobczak. 2016. Hydrological and biogeochemical controls on watershed dissolved organic matter transport: Pulse-shunt concept. Ecology (Concepts and Synthesis) 97: 5-16. Download
Sobczak, W. V. and P. A. Raymond. 2015. Watershed hydrology and dissolved organic matter export across time scales: minute to millennium. Freshwater Science (BRIDGES) 34: 392-398. Download
Wilson Henry F., Raymond Peter A., Saiers James E., Sobczak William V., Xu Na (2016) Increases in humic and bioavailable dissolved organic matter in a forested New England headwater stream with increasing discharge. Marine and Freshwater Research 67: 1279-1292. Download
Schade J. D., E. C. Seybold, T. Drake, S. Spawn, W. V. Sobczak, K. E. Frey, R. M. Holmes & N. Zimov. 2016. Variation in summer nitrogen and phosphorus uptake among Siberian headwater streams. Polar Research 35: 24571. Download
Frey K. E., W. V. Sobczak, P. J. Mann, and R. M. Holmes. 2016. Optical properties and bioavailability of dissolved organic matter along a flow-path continuum from soil pore waters to the Kolyma River mainstem, East Siberia. Biogeosciences 13: 2279-2290. Download
Heslop J. K., S. Chandra, W. V. Sobzcak, S. P. Davydov, A. I. Davydova, V. Spektor, K. M. Walter Anthony. 2016. Variable respiration rates from incubated permafrost soil extracts in the Kolyma River lowlands region of Northeast Siberia. Polar Research (In Press). Download
Connolly*, C. T., W. V. Sobczak, and S. Findlay. 2014. Salinity effects on Phragmites decomposition dynamics among the Hudson River’s freshwater tidal wetlands. Wetlands (doi:10.1007/s13157-014-0526-1). Download
Denfeld*, B. A., K. E. Frey, W. V. Sobczak, P. J. Mann, and R. M. Holmes. 2013. Summer CO2 evasion from streams and rivers in the Kolyma River basin, northeast Siberia. Polar Research 32:19704 (doi:org/10.3402/polar.v32io.19704). Download
Mann, P., W. Sobczak, M. LaRue*, K. Bulygina, A. Davydov, J. Vonk, J. Schade, S. Davydov, N. Zimov, R. Holmes, and R. Spencer. 2013. Evidence for key enzymatic controls on metabolism of Arctic River organic matter. Global Change Biology (doi:10.1111/gcb.12416). Download
Wilson, H. F., J.E. Saiers, P.A. Raymond, and W.V. Sobczak. 2013. Hydrologic drivers and seasonality of dissolved organic carbon concentration, nitrogen content, bioavailability, and export in a forested New England stream. Ecosystems (doi:10.1007/s10021-013-9635-6). Download
Vonk JE, Mann PJ, Davydov S, Davydov A, Spencer RG, Schade J, Sobczak WV, Zimov N, Zimov S, Bulygina E, Eglinton TI, Holmes RM. 2013. High biolability of ancient permafrost carbon upon thaw. Geophysical Research Letters (doi: 10.1002/grl.50348). Download
Bain, D. J., M. B. Green, J. L. Campbell, J. F. Chamblee, S. Chaoka, J. M. Fraterrigo, S. S. Kaushal, S. L. Martin, T. E. Jordan, A. J. Parolari, W. V. Sobczak, D. E. Weller, W. M. Wolheim, E. R. Boose, J. M. Duncan, G. M. Gettel, B. R. Hall, P. Kumar, J. R. Thompson, J. M. Vose, E. M. Elliott, and D. S. Leigh. 2012. Legacy effects in material flux: Structural catchment changes predate long-term studies. BioScience 62: 575-584. Download
Willacker*, J. J., W. V. Sobczak, and E. A. Colburn. 2009. Stream macroinvertebrate communities in coupled hemlock and deciduous watersheds. Northeastern Naturalist 16: 101-112. Download
Rowell*, T. J. and W. V. Sobczak. 2008. Will stream periphyton respond to increases in light following forecasted regional hemlock mortality? Journal of Freshwater Ecology 23: 33-40. Download
Collins*, B. M., W. V. Sobczak, and E. A. Colburn. 2007. Subsurface flowpaths in a forested headwater stream harbor a diverse macroinvertebrate community. Wetlands 27: 319-325. Download
Rainey, J. D., W. V. Sobczak, and S. C. Fradkin. 2007. Zooplankton diel vertical distributions in Lake Crescent, a deep oligotrophic lake in Washington (USA). Journal of Freshwater Ecology 22: 469-476
Sobczak, W. V. 2005. Lindeman’s trophic-dynamic aspect of ecology: Will you still need me when I’m 64? Bulletin of the American Society of Limnology and Oceanography 14: 53-57. Download
Ellison, A. M., M. S. Bank, B. D. Clinton, E. A. Colburn, K.Elliott, Chelcy R. Ford, D. R. Foster, B. D. Kloeppel, J. D. Knoepp, G. M.Lovett, J. Mohan, D. A. Orwig, N. L. Rodenhouse, W. V. Sobczak, K. A. Stinson,P. Snow, J. K. Stone, C. M. Swan, J. Thompson, B. Von Holle, and . R.Webster .2005. Loss of foundation species:consequences for the structure and dynamics of forested ecosystems. Frontiers in Ecology and the Environment 3: 479-486. Download
Findlay, S.E. G., R. L. Sinsabaugh, W. V. Sobczak, and M. Hoostal. 2003. Metabolic and structural response of hyporheic microbial communities to variations in supply of dissolved organic matter. Limnol.Oceanogr., 48:1608–1617 Download
Sobczak, W. V., S. Findlay, and S. Dye. 2003. Relationships between DOC bioavailability and nitrate removal in an upland stream: An experimental approach. Biogeochemistry 62: 309-327 Download
Sobczak, W. V., J. E. Cloern, A. D. Jassby, and A. Mueller-Solger. 2002. Bioavailability of organic matter in a highly disturbed estuary: The role of detrital and algal resources. Proceedings of the National Academy of Sciences USA 99: 8101-8105. Download
Sobczak, W. V. and S. Findlay. 2002. Variation in bioavailability of dissolved organic carbon among stream hyporheic flowpaths Ecology: 83: 3194-3209. Download
Lovett, G. L., K. W. Weathers, and W. V. Sobczak. 2000. Nitrogen saturation and retention in forested watersheds of the Catskill Mountains, New York. Ecological Applications 10:73-84. Download
Findlay, S. and W. V. Sobczak. 2000. Microbial communities in hyporheic sediments. IN: Streams and Ground Waters. Jones, J. & P. Mulholland (Eds.). Academic Press, New York.
Sobczak, W. V., L. O. Hedin, and M. J. Klug. 1998. Relationships between bacterial productivity and organic carbon at a soil-stream interface. Hydrobiologia 386: 45-53. Download
Findlay, S., R. O. Hall, and W. V. Sobczak. 1998. Book Review: Methods in Stream Ecology (R. Hauer & G. Lamberti eds.). Limnology and Oceanography 43: 1021-1022.
Sobczak, W. V. 1996. Epilithic bacterial responses to variations in algal biomass and labile DOC during biofilm colonization. Journal of the North American Benthological Society 15:143-154. Download
Findlay, S. and W. V. Sobczak. 1996. Variability in removal of dissolved organic carbon in hyporheic sediments. Journal of the North American Benthological Society 15:35-41. Download
Sobczak, W. V. and T. M. Burton. 1996. Epilithic bacterial and algal colonization among a stream run, riffle, and pool: a test of co-variation. Hydrobiologia 332:159-166. Download