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Tension-free lysimeters were installed in three soil horizons at three locations adjacent to Hubbard Brook Experiment Forest Watershed 6. At each location lysimeters were placed beneath the Oa horizon and within the upper and lower B horizon. Soil solution samples were collected approximately monthly and analyzed for pH, acid neutralizing capacity (ANC), base cations, soluble anions, trace metals, nitrogen and carbon. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

Longitudinal variation in streamwater chemistry has been measured in two watersheds (W1 and W6) at the Hubbard Brook Experimental Forest. This dataset includes samples that have been collected approximately monthly in Watershed 6 at six sampling locations (1982 - present) along an elevational gradient. Samples are analyzed for pH, ANC, anions, cations, nitrogen, dissolved inorganic and organic carbon. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

Tension-free lysimeters were installed in three soil horizons at 13 locations within Hubbard Brook Experimental Forest Watershed 1, representing the variation in elevation and forest type of the watershed. At each location lysimeters were placed beneath the Oa horizon and within the upper and lower B horizon. Soil solution samples were collected approximately monthly and analyzed for pH, acid neutralizing capacity (ANC), base cations, soluble anions, trace metals, nitrogen and carbon. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

Longitudinal variation in streamwater chemistry has been measured in two watersheds (W1 and W6) at the Hubbard Brook Experimental Forest. This dataset includes samples that have been collected approximately monthly in Watershed 1 at five sampling locations (1991 - ongoing) along an elevational gradient. Samples are analyzed for pH, ANC, anions, cations, nitrogen, dissolved inorganic and organic carbon. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

Understanding the elemental and structural composition of mercury-dissolved organic matter (Hg-DOM) complexes is crucial for comprehending Hg speciation, bioavailability, and transformations in aquatic ecosystems. However, low concentrations of these organo-metal complexes in natural waters and extraction at acidic pH constrain their characterization. Here, we used solid phase extraction (SPE) methodology to extract Hg-DOM complexes at ambient pH and validated their preconcentration by preserving the composition for identification using ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). While the dissolved organic carbon (DOC) extraction efficiency was higher with cartridges containing styrene divinylbenzene copolymer (PPL) than silica structure bonded with hydrocarbon chains (C18), Hg in both extracts showed no significant difference. FT-ICR-MS analysis revealed that Hg-DOM complexes extracted by C18 cartridges were aliphatic with smaller carbon chains (16-18), whereas complexes extracted with PPL exhibited both aliphatic and aromatic characteristics with a wide distribution of carbon chains ranging from 17 to 25. The C18 cartridge appeared to be selective in extracting and preserving the nonpolar complexes, as evidenced by the identification of two molecular formulae, C16H31HgNO3 and C16H35HgNO2S, with m/z ratios of 487.2 and 507.21, across triplicate extractions. This study addresses the challenge of the spectroscopic limitation of Hg-DOM identification by extracting these complexes at circumneutral pH and presumably preserving them from dissociation during extraction. 

Identifying which aspects of global environmental change are driving observed ecosystem process responses is a great challenge. Here, we address how long-term (10-25 year) alterations in soil moisture, and nitrogen (N) oligotrophication (i.e. decreases in soil N availability relative to plant demand), alter the production of plant-available N via net mineralization and nitrification in a northern hardwood forest. Our objectives were to determine whether soil moisture has changed over the past decade and whether N cycle processes have become less sensitive to soil moisture over time due to N oligotrophication. We used long-term data sets from several related studies to show: (i) increasing winter soil temperatures and declining summer soil moisture from late 2010 into 2024; (ii) reductions in sensitivity of N cycling rates to soil moisture, and (iii) declining moisture-adjusted N cycle processes (the ratio of rate of N process:soil moisture) over time in both summer and winter. These changes suggest continued reductions in N availability to plants in these forests, with potential effects on forest productivity and response to disturbance. 

Longitudinal variation in streamwater chemistry has been measured in two watersheds (W1 and W6) at the Hubbard Brook Experimental Forest. This dataset includes samples that have been collected approximately monthly in Watershed 1 at five sampling locations (1991 - ongoing) along an elevational gradient. Samples are analyzed for pH, ANC, anions, cations, nitrogen, dissolved inorganic and organic carbon. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

Tension-free lysimeters were installed in three soil horizons at 13 locations within Hubbard Brook Experimental Forest Watershed 1, representing the variation in elevation and forest type of the watershed. At each location lysimeters were placed beneath the Oa horizon and within the upper and lower B horizon. Soil solution samples were collected approximately monthly and analyzed for pH, acid neutralizing capacity (ANC), base cations, soluble anions, trace metals, nitrogen and carbon. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

Tension-free lysimeters were installed in three soil horizons at three locations adjacent to Hubbard Brook Experiment Forest Watershed 6. At each location lysimeters were placed beneath the Oa horizon and within the upper and lower B horizon. Soil solution samples were collected approximately monthly and analyzed for pH, acid neutralizing capacity (ANC), base cations, soluble anions, trace metals, nitrogen and carbon. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

Longitudinal variation in streamwater chemistry has been measured in two watersheds (W1 and W6) at the Hubbard Brook Experimental Forest. This dataset includes samples that have been collected approximately monthly in Watershed 6 at six sampling locations (1982 - present) along an elevational gradient. Samples are analyzed for pH, ANC, anions, cations, nitrogen, dissolved inorganic and organic carbon. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.