Assessing Carbon Storage Potential of Forested Wetland Soils in Two Physiographic Provinces of Northern Virginia, USA

Kathryn Ledford,Changwoo Ahn,Stephanie Ann Schmidt

doi:10.3390/su14042048

Abstract

This study assessed the soil carbon storage potential in terms of the total carbon (TC) and total carbon stocks (TC stocks) and associated soil physicochemical properties (i.e., soil pH, bulk density (Db), and gravimetric soil moisture (GSM)) for four forested wetlands in the urbanized region of Northern Virginia (NOVA). The study sites were balanced between the two physiographic provinces of the region (Piedmont vs. Coastal Plain); at each site, soils were sampled and analyzed (n = 180) at three depth intervals (0–10 cm; 10–20 cm; 20–30 cm). There was no significant difference in TC stocks between physiographic provinces (p > 0.05); however, wetland soils had higher TC contents at the Coastal Plain (4.32 ± 0.41%) than in Piedmont (2.57 ± 0.22%; p < 0.05). Both Db and GSM significantly differed by physiographic province and were highly correlated to TC, indicating that the TC variability is strongly explained by Db (R2 = 0.38) or GSM (R2 = 0.39), respectively (p < 0.01 for all). These outcomes highlight the capacity of urban forested wetlands to store carbon, especially in their topsoil (top 10 cm). Elucidating the carbon storage potentials of forested wetlands in an urbanized landscape may assist with future efforts to combat urban carbon emissions.

Highlights

In wetland ecosystems, soil acts as the primary medium for biogeochemical transformations and storage of nutrients that provide important ecosystem services, such as carbon sequestration and storage [1,2]
Wetlands were balanced between the Piedmont and Coastal Plain physiographic provinces; Piedmont (P) sites include Algonkian Regional Park, Loudoun County (ARP; 39◦ 590 9” N, 77◦ 370 36” W) and Banshee Reeks Nature Preserve, Loudoun County (BR; 39◦ 360 73” N, 77◦ 590 17” W), and Coastal Plain (CP) sites include Julie J
analysis of variance (ANOVA) revealed significant differences in all soil physicochemical properties as well as carbon content and nitrogen content between sites when separated into 10 cm intervals, and differences in all but Db when considering the top 30 cm overall (p < 0.05; Table 2)

Summary

Introduction

Soil acts as the primary medium for biogeochemical transformations and storage of nutrients that provide important ecosystem services, such as carbon sequestration and storage [1,2]. Tracking and assessing wetland soil carbon stocks is key to understanding how certain physicochemical and physiographic settings may affect a wetland’s capacity to store carbon in the era of anthropogenic climate change. Modeling carbon sequestration and storage potentials from in situ carbon stocks requires knowledge of the relationships between a given site’s soil carbon and soil physicochemical properties [7]. Previous efforts to quantify and track the carbon storage potential have provided useful insights into these relationships, indicating that plot-specific soil physicochemical properties such as bulk density (Db ), pH, and gravimetric soil moisture (GSM) can inform measurements of soil functional properties, including carbon stocks [8,9,10,11,12]. Soil carbon investigations that capture geographic and site variability in soils can provide context to a study on urbanized wetland soils at a regional scale [13,14,15]

Methods

Results

Conclusion