Multi-element composition of soils of seasonal wetlands across North Dakota, USA

Practical Guide to Measuring Wetland Carbon Pools and Fluxes

Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13157-023-01722-2.

Changes in Soil Quality of an Urban Wetland as a Result of Anthropogenic Disturbance

Urban wetland soil provides ecosystem services (ES) through their functions. Changes in soil properties due to anthropogenic disturbances lead to a loss of soil quality. The aim of this research was to evaluate the effect of nearby anthropic disturbance on the chemical, physical and biological properties of the urban wetland soil. Soil samples were collected from four sites (P1, P2, P3 and P4) located in the Angachilla urban wetland, Chile, according to the magnitude of anthropogenic disturbance. An assessment of the physical and chemical properties of the soil profile was carried out in two sites, P1 and P4. Additionally, chemical and biological properties of the soil were evaluated in the four sites selected. Results from the soil profiles showed that Hz1 of P4 had a higher levels of soil fertility as a result of low anthropogenic disturbance in contrast to Hz1 of P1 (p < 0.05). Relevant differences among sites were observed for P-Olsen, pH NaF, nosZ gene, Nitrate and Na (PC1: 50.5%). Composition of the soil bacterial community in P1 and P4 showed higher richness and diversity. Anthropogenic disturbance on the urban wetland soil leads to a loss of the soil’s organic horizon, as well as its soil quality and, subsequently, its capacity to provide ES through its functions.

Multi-element fingerprinting of soils can reveal conversion of wetlands to croplands

Little is known about the influence of conversion of wetlands to farmlands on concentrations and distribution of elements other than those most commonly studied, partly because of the lack of stratification in wetland soils. In this study, in the Sanjiang Plain in northeastern China, we determined the concentrations of 63 elements along soil profiles at three depths: 0-20 cm, 20-40 cm, and below the depth to which farmers would plow, at 40-60 cm, under four land uses: natural wetland, drained wetland, wetland converted to soybean field and subsequently to rice paddy field. Based on our previous work, we expected that changes in organic matter content would be an important factor affecting element concentrations, but that changes in land uses also led to decoupling of the influence of organic matter on elements. This would lead to other factors, such as changes in redox conditions, changes in hydrology and mixing of soils due to plowing, becoming more important factors affecting element distributions. Our study confirmed these expectations. Changes in organic matter content directly or indirectly affected many elements, explaining 67% of variation. Arsenic, cobalt, iron and nickel concentrations were dramatically higher and sulfur concentrations lower when wetland was converted to paddy field. Co and Ni were identified as potential chemical indicators of wetland conversion. Our research is the first to use multi-element fingerprinting to study effects of conversion of wetlands to croplands in China and showed that this relatively simple approach highlights the complexity of the many interacting factors in reclamation of wetland soils for agricultural uses.