CARBON DYNAMICS AND HYDROMORPHOLOGY IN DEPRESSIONAL WETLAND SYSTEMS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1020054
• Multistate No.: NE-1938
• Project Start Date: Oct 1, 2019
• Project End Date: Sep 30, 2024
• Program Code: [(N/A)]- (N/A)

Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
208 MUELLER LABORATORY
UNIVERSITY PARK,PA 16802

Performing Department
Ecosystem Science & Management

Non Technical Summary
The depressional wetland systems identified across the region are distributed acrossclimatic gradients, across parent material types (coastal plain, residual, and glacial), and amongdifferent geomorphological settings. This regional project will permit the development andtesting of hypotheses in a way that is not possible for a single investigator working within asingle state. Addressing these questions within a regional framework is also critical because themajor agencies that use the soils information that pedologists collect, such as USDA-NRCS,USACOE, and USEPA, all work in a region-wide context. In addition, working groups such asthe New England Hydric Soil Technical Committee and id-Atlantic Hydric Soils Committee,who offer guidance to regional regulatory bodies like the New England Interstate WaterPollution Control Commission (http://www.neiwpcc.org/), need soils information that is notrestricted by state boundaries. Recent focus of the USACOE and other federal agencies todevelop regional supplements as amendments to the 1987 Wetlands Delineation Manual(Environmental Laboratory, 1987) provide additional incentive to work region-wide in appliedresearch. This project will enhance current collaborations and will foster and facilitate newcollaborations across the region.

Animal Health Component

40%

Research Effort Categories

Basic

50%

Applied

40%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	0110	2061	100%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
0110 - Soil;

Field Of Science
2061 - Pedology;

Keywords

wetland

hydric

soil

greenhouse gas

carbon

Goals / Objectives
To better understand the hydrological, biogeochemical and pedologcial properties and processes that affect SOM decomposition, CO2 and CH4 greenhouse gas fluxes, and C sequestration in depressional wetland ecosystems, as expressed across geographical and climatic gradients. To determine the relationship between soil and air temperature and accumulated soil C stocks and fluxes in depressional wetland systems. To determine the relationship between hydroperiod (i.e. duration of saturation and inundation) and accumulated soil C stocks and fluxes in depressional wetlands. To seek to develop morphological indices of the hydroperiod within depressional wetlands in order to estimate or predict C stocks.

Project Methods
Site SelectionSites previously selected across the region for study by the PIs and generally characterized, will be utilized.Plot Layout and Experimental DesignIn each wetland study site, 3 hydrological zones were identified, corresponding to the predominant soil, plant, and water characteristics at each location. Zone 1 is seasonally ponded, and typically contains hydrophytic vegetation (emergent, shrub or woody). Zone 2 is a wetland zone marked by saturation, but not significant ponding. It contains hydrophytic vegetation (woody) and hydric soils. Zone 3 is the upland area beyond the wetland boundary. Hydric soils are not present in zone 3, although in some cases hydrophytic vegetation can be observed adjacent to, and outside the boundary of, the wetland zones.Within each site, nine research plots have been identified along three transects. Each of the transects extends radially outwards from the center of the vernal pool (zone 1) through zone 2 and into the upland. Along each transect, a single plot was centrally located within each of the hydrological zones.HydrologyThe depth of ponded water or the depth to the water table (below the surface) will continue to be recorded at each site. Depth of ponded water is measured using a staff gauge. Monitoring ports consisting of a well screen installed to a depth of 100 cm have been placed at each plot and water tables will continue to be measured periodically (Figure 3). Along a single transect at each site, water table recording devices have been installed and programmed to record water table levels daily. Also along a single transect, nests of piezometers have been installed to help with interpretation of hydrological flow patterns.Soil MorphologyIn the vicinity of each plot, a soil profile description has been made to a depth of 1 to 2 m according to standard protocols (Schoeneberger et al., 2012). Samples collected from each horizon have been stored for laboratory analysis.Vegetation AnalysisPlant communities in each of the three zones will be assessed by methods outlined in the 1987 USACOE Wetland Delineation Manual (Environmental Laboratory, 1987) and the appropriate regional supplement (USACOE, 2010, USACOE, 2012a, USACOE, 2012b).Weather and Climate DataIn order to generalize and extend hydrological observations from the period of this study to the broader context, weather data will be obtained from the nearest weather station that maintains a long term (30+ years) record of daily precipitation and air temperatures. Dailyrecords of precipitation and of minimum and maximum temperatures will be collected for the period of this study and will also be obtained for a minimum of the previous 30 years.Quantification of Carbon and Nitrogen StocksCarbon and nitrogen stocks will be determined at plots along each transect (Vasilas et al., 2013). A soil core will be collected from the upper 50 cm in a way that permits simultaneous calculation of horizon thickness and soil bulk density. Within each plot, a section of aluminum tubing (sharpened on the leading edge) (60 cm long and 5 cm diameter) will be driven 50 cm into the soil.Total carbon will be determined in duplicate by dry combustion (Nelson and Sommers, 1996).Soil Inorganic NitrogenSoil nitrate and ammonium will be measured on samples collected from each plot in the middle to end of the aerobic phase (August -September). Four to six replicate cores will be collected using a 30 cm push probe, and will be aggregated into a single composite homogenized sample for analysis. Samples will be analyzed using the HACH 8171 method.Soil Redox AssessmentIRIS (indication of reduction in soil) films will be used to assess the reducing soil conditions within each plot (Rabenhorst, 2008, 2018; Rabenhorst and Burch, 2006; Rabenhorst et al., 2008; Vasilas et al., 2013). Both traditional Fe-coated and newly developed Mn-coateddevices will be utilized (Rabenhorst and Persing, 2017; Rabenhorst and Post, 2018). Five replicate IRIS films of each type (Fe and Mn) will be deployed at each plot to a depth of 50 cm. The extent of reduction on IRIS films will be assessed using digital image analysis (Rabenhorst, 2012).Carbon InputsReplicate measurements of litterfall will be made within each plot along the central transect at each site. Leaf litter deposition will be measured between the months of December to August, and September to November using plastic devices to collect litter.Three randomly placed C inputs as deadfall will be determined in each plot. Deadfall will be considered as any woody debris greater than 1 cm in diameter. Existing deadfall and leaf litter will be cleared from the forest floor upon delineation of each plot. Each year deadfall that has accumulated in the plots will be collected. Carbon inputs will be estimated assuming a concentration of 0.50 g C g-1 of leaf litter (Davis et al., 2010).Organic Matter DecompositionDuring the previous study northern white birch (Betula papyrifera) sticks (9.5 mm dowels, 30 cm long) were inserted into the soil and then extracting following one year of burial in order to assess the relative rates of organic matter decomposition. This approach was basedupon other studies showing that wooden sticks can be used to indicate organic matter decomposition rates in several different types of settings (Baker et al., 2001; Gulis et al., 2004; Ostertag et al., 2008). Five replicate nylon mesh leaf-litter bags will be filled with dried, pre-weighed leaves of species native to each site and secured at the soil surface in each zone. Two sets of five replicate pre-weighed northern white birch (Betula papyrifera) dowels (15 cm in length and either 1 cm or 2 cm in diameter) will be secured at the soil surface at each research plot at the same time as the leaf litter bags. The bags and dowel rods will left on the soil surface for a year (May to May), dried in the oven, and the difference in weight before and after will be calculated as a measure of degree of decomposition.Greenhouse Gas FluxFlux rates of major greenhouse gasses will be measured at each research plot on each of the three transects at each site, using a closed chamber approach, thus providing data for each of the three hydrologic zones. Two cylindrical plastic chambers (16 cm in height, 20 cm indiameter) will be placed at each site and pushed approximately 2.5 cm into the soil. Using a 20 ml gas-tight syringe, an initial gas sample will collected after securing the chamber's lid, which contained a rubber septum to allow for sampling, followed by samples taken 15 and 30 minutes after the initial sample. In each sample, CO2, CH4, and N2O will be determined. Soil temperature at a depth of 10 cm, and specific chamber volume (m3) will be recorded at each sample period (Ricker et al., 2014; Waggoner, 2016). Gas concentrations (CO2, CH4, and N2O) will be measured with a Shimadzu gas chromatograph and recorded in units of ppm (Altor and Mitsch, 2008). The rate of GHG production per unit area is calculated using the slope of the bestfit line, cross-sectional area of the chamber, and volume of air in the chamber (Waggoner, 2016).Data AnalysisStatistical analysis of the data will be conducted using the most appropriate statisticalprocedure after consultation with statisticians in the College of Agriculture & Natural Resources at the University of Delaware. At this stage we anticipate the following statistical procedures.To identify site differences or treatment differences (i.e. zone) data such as % decomposition will be subjected to an analysis of variance (ANOVA) using either PROC ANOVA or PROC GLM of the SAS System, Version 9.1.3 (SAS Institute, Inc., 2004) as a complete data set and then by regional group as warranted.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:The target audience reached for this reporting period were laregly fellow scientists attending scientific meetings. Efforts included presentations made to fellow scientists and government employees of a variety of ethnic backgrounds and genders. Efforts also included a scientific panel on which Dr. Drohan served at the Irish Catchments program meeting where he gave his keynote address. Changes/Problems:COVID-19 has severely hampered furthur progress on this project given restrictions on personnel in University vehicles, rules on social distancing in the field, and rules on interaction with the public. As the pandemic evolves we are doing our best to make progress. What opportunities for training and professional development has the project provided?While COVID-19 severely hampered efforts, PhD student Daniel Guarin continues the former work of PhD student Shauna Kay Rainford. Daniel is early in his thesis work but did collect one core this Fall. One PhD student completed her degree on work related to this project (Fei Jiang). MS student Emily Lesher has begun her research on related project work, but is looking more at agricultural water quality issues tied to depressional landscapes. Ms. Lesher is working with USDA Agricultural Research Service (ARS) personnel at the Klingerstown Research Watershed study area known as WE-38, and is examining how high-resolution landscape modeling of critical source areas (CSAs) can identify landscape intersections between high phosphorus soils and high runoff landscape positions. Dr. Drohan continues to use research results from this project in courses he teaches at Penn State (SOILS 403, Soil Morphology Practicum; SOILS 416, Soil Genesis, Classification, and Mapping). How have the results been disseminated to communities of interest?Results have been dissmeinated through a number of peer-reviewed jounral articles and conference presentations. COVID-19 resulted in the cancellation of a June outreach event for this project at Virgina Tech. What do you plan to do during the next reporting period to accomplish the goals?What we plan to do depends on COVID-19, University policies on research, and remaining project funds. Project funds are restricted to wage employees who work in the field. Dr. Drohan is not allowed to hire undergraduate students in this capacity given University vehicle policy and COVID-19. Daniel Guarin, a PhD student in Drohan's lab, continues his field sampling at these study vernal pools and will be investigating long-term hydrologic and soil carbon dynamics outlined in the project's goals.

Impacts
What was accomplished under these goals? Goal 1) A) Major activities completed / experiments conducted; Our vernal pool research continues to focus on moss (Bryophyte) populations in rare Northern Appalachian vernal pools. Bryophytes are important contributors to carbon (C) sequestration in wetland environments and play an important role in regulating the effect of global climate change on C and nitrogen (N) cycles. As such, it is important to understand patterns in bryophyte community composition and their dependent nutrient availability in wetlands. We have been monitoring vernal pools in the Northern Appalachians, which differ in climate and the soil forming process and thus provide an important contrast of the effect of soil forming factors on bryophyte carbon dynamics in soils. Research sites are in the Ridge and Valley (RV) and Appalachian Plateau (AP) Physiographic Provinces. B) Data collected; Soil profile descriptions of vernal pools have been written. Monitoring has included plant species measures, soil bulk sampling and core sampling. An additional core was taken in September 2020. Pollen data and C14 data has been generated from previous cores. C) Summary statistics and discussion of results; Our results show that wetland soils of the two physiographic provinces exhibit differences in bryophyte species richness, biomass, and total organic carbon (TOC) and nitrogen availability due to micro-site climate conditions and parent material. Mineral-associated soil organic carbon retention capacity results suggest property differences have a limited effect on shallow carbon sequestration. Variations in C input due to differing bryophyte species richness and biomass may lead to vernal pools in the two contrasting provinces having different TOC retention capacities, but similar potential for long-term C sequestration. D) Key outcomes or other accomplishments realized; Our research has resulted in changes in knowledge about soil carbon dynamics in vernal pool environments, the age and genesis of vernal pool environments studied, and species change over the last 6,000 to 11,000 years. Students involved in the project have developed new skills. Goal (2) Our research does not focus on thisaspect of the project. Goal (3) A) Major activities completed / experiments conducted; Water tables continue to be monitored. Pollen analysis and soil profile analysis havebeen completed. B) Data collected; Long-term species assemblages have been generated and interpreted in relation to the wetness of a site over time. C) Summary statistics and discussion of results; There were observable changes in the plant community composition throughout the Holocene in the two physiographic regions of central Pennsylvania. During the early Holocene vegetation in the RV Province vernal pool was sparse and dominated by a few arboreal species such as Nyssa, Tsuga, Quercus, and Pinus. Smaller percentages of nonarboreal vegetation pollen (NAP) such as grasses, monolete ferns, and Polygonum were also represented. It is surprising that the pollen record in the AP Province was not captured during this time. D) Key outcomes or other accomplishments realized; While both physiographic provinces maintained similar kinds of plant taxa, regional factors influenced vegetation composition in each area during the mid- to late-Holocene. At the onset of the pollen record in the AP Province there were observable declines in Nyssa and increases in Betula, Carya, and Quercus. A similar pattern was observed in the RV Province between ~4,758 and ~2,910 cal. yr. before present (BP). Additionally, zonal shifts in the late-Holocene, specifically RV-2a in the RV Province (around ~1,886 cal. yr. BP) and AP-2 in the AP Province (~2,255 cal. yr. BP) occurred at similar times. This is expected in areas that experience a similar climate, since the fundamental niche preferences of the flora may be similar. However, regional differences in the species' composition in each area may be due to specific differences in the realized niches of specific taxa. For example, hardwood taxa such as Betula, Carya, Nyssa, Quercus, and Pinus displayed similar patterns in occurrence;but the vegetation record is more diverse and there were higher percentages of the common species in the RV Province. Goal (4) A) Major activities completed / experiments conducted; Our research focused on developing new techniques to document carbon fractions in wetland soils. We used mid-infrared spectroscopy (MIR) and partial least-squares (PLS) analysis to predict the concentration of carbon and its component mineral-associated soil organic carbon (SOC) fraction in vernal pools, or ephemeral wetlands located in two physiographic provinces of central Pennsylvania. B) Data collected; Laboratory fractionations of SOC using the acid hydrolysis chemical fractionation procedure were conducted on 341 samples collected in the topsoil of 6 vernal pool sites. C) Summary statistics and discussion of results; MIR-PLS models were developed and cross-validated to predict the content of total C using different subsets of soil samples. Results demonstrated that mid-infrared spectroscopy and PLS can provide a rapid, non-destructive method for determining total C and the mineral-associated SOC fraction across the combined organic and mineral horizons commonly found in vernal pool, wetland environments. D) Key outcomes or other accomplishments realized; Our results are presently being reviewed in submitted peer-reviewed manuscripts.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Jiang F*, Preisendanz HE, Veith TL, Raj C, Drohan PJ (2020) Riparian buffer effectiveness as a function of buffer design and input loads. Journal of Environmental Quality. https://doi.org/10.1002/jeq2.20149
• Type: Journal Articles Status: Under Review Year Published: 2020 Citation: Jiang F*, Drohan PJ, Raj C, Preisendanz HE, Veith TL. Reallocating crop rotation patterns improves water quality and maintains crop yield. In review, Agricultural Systems.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Drohan PJ, Bechmann M, Buda A, Djodjic F, Doody D, Duncan JM, Iho A, Jordan P, Kleinman PJ, McDowell R, Mellander PE (2019) A global perspective on phosphorus management decision support in agriculture: Lessons learned and future directions. Journal of Environmental Quality. 48: 1218 - 1233.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Jiang F*, Gall HE, Veith TL, Cibin R, Drohan PJ (2019) Assessment of riparian buffers effectiveness in controlling nutrient and sediment loads as a function of buffer design, site characteristics and upland loadings. American Society of Agricultural and Biological Engineers. 1901516: 1 - 11. doi:10.13031/aim.20190151.
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Lesher, E*, Thomas IA, Drohan PJ, Wells J, Spargo J, Djodic F, Kleinman P (2020) Development and validation of a phosphorus critical source area index tool for Ridge and Valley Physiographic Province agriculture. Northeast Regional Cooperative Soil Survey Meeting, Virginia Tech, Blacksburg, VA.
• Type: Journal Articles Status: Under Review Year Published: 2020 Citation: Rainford S*, Drohan PJ, Brooks, R., Mortensen, D.A. Bryophyte diversity and soil nutrient availability in two contrasting Northern Appalachian vernal pools driven largely by parent material. In review, Catena.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Rabenhorst MR, Drohan PJ, Galbraith JG, Spokas L, Stolt M, Thompson JA, Vasilas BL, Vaughn KL (2019) Biogeochemistry of vernal pools assessed using iris film technology. American Society of Agronomy-Crop Science Society of America-Soil Science Society of America, San Diego, CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Vaughn, KL, Drohan PJ, Galbraith JG, Rabenhorst MR, Spokas L, Stol, M, Thompson JA, Vasilas BL (2019) Redoximorphic feature expression in seasonally inundated soils reveals belowground climatic influence on development. American Society of Agronomy-Crop Science Society of America-Soil Science Society of America, San Diego, CA.