Sediment, stream, and canopy characteristics were measured in four headwater streams in Massachusetts and New Hampshire associated with methane ebullition monitoring. Canopy cover, water depth, sediment organic matter content, the percent sediment less than 2mm in diameter, sediment depth, sediment percent carbon, and sediment percent nitrogen were measured.
Other files to reference: WAT-Methane-Stream
Sediment, stream, and canopy characteristics were measured in four headwater stream associated with methane ebullition monitoring. Within each stream 3-4 patches were selected for monitoring, and the following variables were measured at each patch: canopy cover, water depth, sediment organic matter content, the percent sediment less than 2mm in diameter, sediment depth, sediment % carbon, and sediment % nitrogen were measured.
Canopy cover was estimated using a convex spherical densiometer (Forestry Suppliers, Inc., Model-C, Mississippi, USA) at each patch within each stream. Water depth was found using the mean of 10 locations measured with a meter stick in each patch. Following Crawford and Stanley (2016), depth to refusal was measured as a means of approximating the depth of sediments overlying hard mineral sediments. Fifteen measurements were made at each patch, five measurements along three replicate channel cross-sections, and the average was used as the patch metric. Finally, sediment cores were collected near all patches and separated into subsamples representing 5 cm depth intervals from 0 cm to the deepest collected sample (maximum sampling depth varied from 10 to 35 cm). A Multi Stage Soil Core Sampler (AMS, Inc., Idaho, USA), which consists of a stainless steel cylinder and a 5 cm diameter plastic liner, was driven into the stream sediments using a sliding weight stand (Wik et al. 2018). Sediment cores were located at least 1 m away from traps to minimize disturbance. Subsamples were analyzed for OM content by loss of mass on ignition. The percent of sediment smaller than 2 mm in diameter was determined by passing subsamples through a 2 mm sieve and weighing each fraction. Finally, sediment carbon and nitrogen content were measured on dry pulverized samples by elemental analysis using a Thermo FlashEA Series 1112 at the USDA Forest Service, Louis C. Wyman Forest Sciences Laboratory in Durham, NH.
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