Geology Reports⌕ Search
Home/Archive/USGS

USGS · 70020046

Assessment of soil calcium status in red spruce forests in the northeastern United States

G.B. Lawrence·M.B. David·S.W. Bailey·W.C. Shortle
View original source ↗Export metadata ↓

Abstract

Long-term changes in concentrations of available Ca in soils of red spruce forests have been documented, but remaining questions about the magnitude and regional extent of these changes have precluded an assessment of the current and future status of soil Ca. To address this problem, soil samples were collected in 1992-93 from 12 sites in New York, Vermont, New Hampshire, and Maine to provide additional data necessary to synthesize all available research results on soil Ca in red spruce forests. Sites were chosen to encompass the range of environmental conditions experienced by red spruce. Concentrations of exchangeable Ca ranged from 2.13 to 21.6 cmol(c) kg-1 in the Oa horizon, and from 0.11 to 0.68 cmol(c) kg-1 in the upper 10 cm of the B horizon. These measurements expanded the range of exchangeable Ca reported in the literature for both horizons in northeastern red spruce forests. Exchangeable Ca was the largest Ca fraction in the forest floor at most sites (92% of acid-extractable Ca), but mineral Ca was the largest fraction at the three sites that also had the highest mineral-matter concentrations. The primary factor causing variability in Ca concentrations among sites was the mineralogy of parent material, but exchangeable concentrations in the B horizon of all sites were probably reduced by acidic deposition. Because the majority of Ca in the forest floor is in a readily leachable form, and Ca inputs to the forest floor from the mineral soil and atmospheric deposition have been decreasing in recent decades, the previously documented decreases in Ca concentrations in the forest floor over previous decades may extend into the future.

Explore related subjects

BiogeochemistryArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G.B. Lawrence, M.B. David, S.W. Bailey, W.C. Shortle. 1997. Assessment of soil calcium status in red spruce forests in the northeastern United States. https://doi.org/10.1023/a%3A1005790130253

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Water table rise sustains carbon release from soils in wetland-dominated landscapes: An intact soil core study

Wetland-dominated landscapes influence carbon cycling through their potential to act as both carbon sinks and sources. Wetlands in low-relief landscapes have dynamic terrestrial-aquatic interfaces that change seasonally with variable surface water and groundwater levels. However, few studies have directly quantified dissolved organic matter (DOM) release and greenhouse gas (CO 2 , CH 4 ) fluxes from wetland soils along terrestrial-aquatic interfaces as they are seasonally re-saturated by groundwater. To estimate groundwater-mediated soil DOM and gas fluxes, we performed laboratory simulations of vertical groundwater rise on intact soil cores collected from four Delmarva bay wetlands located in the Mid-Atlantic United States. At each wetland, one core was collected from within the wetland basin and the other from the transitional zone at the basin edge. Cores were re-saturated with groundwater over 15 days and then kept fully saturated for an additional 25 days. Source groundwater, soil porewater, and exfiltrated surface water samples were collected and analyzed for pH, ORP, DOM concentration, and DOM optical indices. In both the wetland and transition zone cores, porewater DOM concentrations increased over the wet up and were sustained during prolonged saturation. Optical indices shifted from recently produced, microbial-like signatures towards aromatic, terrestrial-like signatures. Fluxes of CO 2 decreased as the duration of soil saturation increased and soil cores switched from CH 4 sinks to sources upon full soil core saturation. Results indicate that groundwater rise sustains carbon mobilization from soils in wetland-dominated landscapes, emphasizing the need to understand how climate-driven changes to groundwater dynamics may affect carbon fluxes along terrestrial-aquatic interfaces.

Delaware, Maryland↗
USGS2025

Seasonal synchronicity and multi-decadal stability of headwater biogeochemistry in the northern temperate zone

Temporal patterns in chemistry of headwater streams reflect responses of water and elemental cycles to perturbations occurring at local to global scales. We evaluated multi-scale temporal patterns in up to 32 y of monthly observations of stream chemistry (ammonium, calcium, dissolved organic carbon, nitrate, total dissolved phosphorus, and sulfate) in 22 reference catchments within the northern temperate zone of North America. Multivariate autoregressive state-space (MARSS) models were applied to quantify patterns at multi-decadal, seasonal, and shorter intervals during a period that encompassed warming climate, seasonal changes in precipitation, and regional declines in atmospheric deposition. Significant long-term trends in solute concentrations within a subset of the catchments were consistent with recovery from atmospheric deposition (e.g., calcium, nitrate, sulfate) and increased precipitation (e.g., dissolved organic carbon). Lack of evidence for multi-decadal trends in most catchments suggests resilience of northern temperate ecosystems or that subtle net effects of simultaneous changes in climate and disturbance regimes do not result in directional trends. Synchronous seasonal oscillations of solute concentrations occurred across many catchments, reflecting shared climate and biotic drivers of seasonality within the northern temperate zone. Despite shared patterns among catchments at a seasonal scale, multi-scale temporal patterns were statistically distinct among even adjacent headwater catchments, implying that local attributes of headwater catchments modify the signals imparted by atmospheric phenomena and regional disturbances. To effectively characterize hydrologic and biogeochemical responses to changing climate and disturbance regimes, catchment monitoring programs could include multiple streams with contributing areas that encompass regional heterogeneity in vegetation, topography, and elevation. Overall, detection of long-term patterns and trends requires monitoring multiple catchments at a frequency that captures periodic variation (e.g., seasonality) and a duration encompassing the perturbations of interest.

Biogeochemistry↗
USGS2025

Rare earth element and phosphorus mobility depend on adsorption to Al-, Fe-, and Mn-oxyhydroxides in a headwater stream in Vermont, USA

We evaluated base cations, Al, Fe, Mn, REEs, DOC, anions, and P mobilization during three discharge events (E-1, E-2, E-3) at the headwater catchment W-9, Sleepers River, Vermont, USA. Peak discharge ranged from 3.696 (E-1) to 0.073 (E-3) mm h −1 . Eight samples from each event were speciated for total (unfiltered-acidified) and dissolved (0.45 µm filtered-acidified). During E-1, total Al, Fe, and Mn increased to maxima of 376 (1790X), 161 (194X), and 38 (45X) µmol L −1 , respectively. Concurrently, total La, Ce, Pr, and Nd increased to maxima of 87 (590X), 114 (671X), 15 (375X), and 53 (408X) nmol L −1 , respectively, greatly exceeding the dissolved fraction. Totals for Er > Yb > Tm > Lu reached comparable enrichments near or at maximum discharge. Discharge ranged from 0.41 to 0.94 mm h −1 during E-2, a snowmelt event. Total Al was comparatively stable; total Fe and Mn increased 15X and 79X, remaining less than total Al. Total La, Ce, Pr, and Nd peaked with total Fe and Mn. E-3, a late summer rain, resembled E-1 but had much lower maxima for all REEs, P, Al, Fe, and Mn. Particulate, total, and dissolved REEs and P correlated with DOC and with total Al, Fe, and Mn over all discharges, with molar Al > Fe > Mn (most samples) for E-1 and E-3. Maximum total and dissolved P declined from 15.4 and 0.89 (E-1) to 0.98 and 0.27 µmol L −1 (E-3), respectively. Particulate REEs correlated strongly (R 2 = 0.95–0.96) with Al, Fe, and Mn particulates eroded from the stream bed and continuously precipitated during and after high discharge of groundwater.

Vermont↗