Cryptic wetlands: integrating hidden wetlands in regression models of the export of dissolved organic carbon from forested landscapes

This study examines the relationship between wetlands hidden beneath the forest canopy (‘cryptic wetlands’) and dissolved organic carbon (DOC) export to streams and lakes in forested ecosystems. In the Turkey Lakes Watershed (TLW), located in the Algoma Highlands of central Ontario, Canada, there is substantial natural variation in average annual DOC export (kgC ha � 1 year � 1 ), ranging from 11Ð 4t o 31Ð5 kgC ha � 1 year � 1 in catchments with no apparent wetlands. We hypothesized that the natural variation in DOC export was related to cryptic wetlands. Cryptic wetlands were derived manually from geographic coordinates that were surveyed with a differential global positioning system, and automatically from identification of topographic depressions and flat slopes (<1Ð5°) within a digital elevation model (DEM) in a geographic information system. For the TLW catchments, which are characterized by shallow soils over bedrock, a significant correlation (r 2 ½ 0Ð9, p< 0Ð001) between manual and automated methods was observed for scales up to 50 m when a light detection and ranging DEM was used for the topographic analysis. Regression models indicated that cryptic wetlands (%) explained the majority of the natural variation in DOC export (kgC ha � 1 year � 1 ), with r 2 D 0Ð88 ( p< 0Ð001) for the model based on the manually derived wetlands and r 2 D 0Ð85 ( p< 0Ð001) for the model based on the automatically derived wetlands. The strength and significance of the automatically derived wetlands (%) versus DOC export (kgC ha � 1 year � 1 ) regression model diminished when other sources of DEMs were used. This

[1]  L. Martz,et al.  The treatment of flat areas and depressions in automated drainage analysis of raster digital elevation models , 1998 .

[2]  D. Schindler,et al.  Atmospheric deposition of nutrients and major ions at the Experimental Lakes Area in northwestern Ontario, 1970 to 1982 , 1987 .

[3]  R. Lal,et al.  Dissolved organic carbon: sources, sinks, and fluxes and role in the soil carbon cycle. , 1998 .

[4]  T. Moore,et al.  Sources, Sinks, and Fluxes of Dissolved Organic Carbon in Subarctic Fen Catchments , 1992 .

[5]  Akira Otsuki,et al.  Production of Dissolved Organic Matter from Dead Green Algal Cells. I. Aerobic Microbial Decomposition , 1972 .

[6]  D. Jeffries.  Foreword. The Turkey Lakes Watershed Study After Two Decades , 2002 .

[7]  L. Band,et al.  Export of nitrogen from catchments within a temperate forest: Evidence for a unifying mechanism regulated by variable source area dynamics , 1998 .

[8]  M. Billett,et al.  A review of the export of carbon in river water: fluxes and processes. , 1994, Environmental pollution.

[9]  Tim R. Moore,et al.  Uncertainty in Predicting the Effect of Climatic Change on the Carbon Cycling of Canadian Peatlands , 1998 .

[10]  T. Moore,et al.  Controls on dissolved organic carbon concentrations in streams, southern Québec , 1990 .

[11]  Steven J. Eisenreich,et al.  Export of dissolved organic carbon and acidity from peatlands , 1989 .

[12]  Pamela A. Matson,et al.  Within-System Element Cycles, Input-Output Budgets, and Nutrient Limitation , 1998 .

[13]  P. Mulholland,et al.  Organic carbon export from upland and forested wetland watersheds1 , 1979 .

[14]  T. Y. Barila,et al.  Membrane filtration – Fluorescent antibody staining procedure for detecting and quantifying Renibacterium salmoninarum in coelomic fluid of Chinook Salmon ( Oncorhynchus tshawytscha ) , 1987 .

[15]  J. Ehrman,et al.  Exports of carbon and nitrogen from river basins in Canada's Atlantic Provinces , 1994 .

[16]  K. Bencala,et al.  Hydrological controls on dissolved organic carbon during snowmelt in the Snake River near Montezuma, Colorado , 1994 .

[17]  Lawrence E. Band,et al.  Regulation of Nitrate‐N Release from Temperate Forests: A Test of the N Flushing Hypothesis , 1996 .

[18]  C. Driscoll,et al.  Seasonal and long-term temporal patterns in the chemistry of Adirondack lakes , 1993 .

[19]  P. Mulholland,et al.  Group report 4: What are the temporal and spatial variations of organic acids at the ecosystem level , 1989 .

[20]  P. Kortelainen,et al.  Content of Total Organic Carbon in Finnish Lakes and Its Relationship to Catchment Characteristics , 1993 .

[21]  David W. Johnson,et al.  Atmospheric deposition and forest nutrient cycling. A synthesis of the Integrated Forest Study. , 1992 .

[22]  R. Sinsabaugh,et al.  Unravelling the sources and bioavailability of dissolved organic matter in lotic aquatic ecosystems , 1999 .

[23]  M. Hutchinson.  A new procedure for gridding elevation and stream line data with automatic removal of spurious pits , 1989 .

[24]  K. N. Eshleman,et al.  The Role of Organic Acids in the Acid‐Base Status of Surface Waters at Bickford Watershed, Massachusetts , 1985 .

[25]  Charles T. Driscoll,et al.  The role of dissolved organic carbon in the chemistry and bioavailability of mercury in remote Adirondack lakes , 1995 .

[26]  P. Dillon,et al.  Effect of landscape form on export of dissolved organic carbon, iron, and phosphorus from forested stream catchments , 1997 .

[27]  Ian K. Morrison,et al.  Organic matter and mineral distribution in an old-growth Acer saccharum forest near the northern limit of its range. , 1990 .

[28]  Monica G. Turner,et al.  DISSOLVED ORGANIC CARBON AS AN INDICATOR OF THE SCALE OF WATERSHED INFLUENCE ON LAKES AND RIVERS , 1999 .

[29]  D. Schindler,et al.  The role of DOC in protecting freshwaters subjected to climatic warming and acidification from UV exposure , 1997 .

[30]  D. Jeffries,et al.  Chemistry of Atmospheric Deposition, the Snowpack, and Snowmelt in the Turkey Lakes Watershed , 1988 .

[31]  Patrick J. Mulholland,et al.  Dissolved Organic Matter Concentration and Flux in Streams , 1997, Journal of the North American Benthological Society.

[32]  J. Hobbie.  Microbial control of dissolved organic carbon in lakes: research for the future , 1992, Hydrobiologia.

[33]  E. Thurman,et al.  Biogeochemistry of aquatic humic substances in Thoreau's Bog, Concord, Massachusetts , 1985 .

[34]  Juan J. Armesto,et al.  Patterns of Nutrient Loss from Unpolluted, Old‐Growth Temperate Forests: Evaluation of Biogeochemical Theory , 1995 .

[35]  Ji‐Hyung Park,et al.  Controls on the dynamics of dissolved organic matter in soils: a review. , 2000 .

[36]  I. Morrison.  Effect of crown position on foliar concentrations of 11 elements in Acersaccharum and Betulaalleghaniensis trees on a till soil , 1985 .

[37]  P Arp,et al.  Gaseous carbon dioxide and methane, as well as dissolved organic carbon losses from a small temperate wetland under a changing climate. , 2002, Environmental pollution.

[38]  Jonathan S. Price,et al.  Advances in Canadian wetland hydrology an biogeochemistry , 2000 .

[39]  E. Gorham.  Northern Peatlands: Role in the Carbon Cycle and Probable Responses to Climatic Warming. , 1991, Ecological applications : a publication of the Ecological Society of America.

[40]  Tim R. Moore,et al.  Hydrology and dissolved organic carbon biogeochemistry in an ombrotrophic bog , 2001 .

[41]  N. W. Foster,et al.  Retention or Loss of N in IFS Sites and Evaluation of Relative Importance of Processes , 1992 .

[42]  K. Beven,et al.  A physically based, variable contributing area model of basin hydrology , 1979 .

[43]  G. Asner,et al.  Dissolved Organic Carbon in Terrestrial Ecosystems: Synthesis and a Model , 2001, Ecosystems.