Water Resources Research Act Program

Details for Project ID 2017MD340B

Can Carbon Amendments Improve Wetland Restoration and Jump-Start Microbial Activity?

Institute: Maryland
Year Established: 2017 Start Date: 2017-03-01 End Date: 2018-02-28
Total Federal Funds: $34,996 Total Non-Federal Funds: $69,990

Principal Investigators: Stephanie Yarwood, Andrew Baldwin

Abstract: The U.S. Clean Water Act and the Maryland Nontidal Wetland Protection Act require that loss of wetlands due to development must be offset by at least 1:1 by created or restored “mitigation” wetlands. The success of newly constructed wetlands is typically determined by the presence of wetland vegetation, the correct hydrology, and hydric soil properties. Unfortunately, there are numerous cases of restored wetlands unable to meet these metrics. Many sites are slow to develop soil organic matter or iron-reducing conditions typical of natural wetlands. In an attempt to improve wetland soil condition, Maryland Department of the Environment (MDE) now requires that organic matter (OM) be added at the time of construction. These additions are supposed to improve water holding capacity, plant nutrient availability and carbon (C) needed by microorganisms, which are key to many of the water quality improvement functions. However, few studies have tested if OM amendments improve wetland establishment or conditions. We propose two microcosm studies to evaluate the use of OM. The first will assess how gas flux, soluble carbon (C), and mineral nitrogen (N) change under different OM amendments and rates of addition. The second will use the same amendments to distinguish the active microbial community by using stable isotope 18O-labelled H2O. We will test for differences in three different OM amendment types: sawdust, a class “A” biosolids product [BLOOM(TM)], and compost, and we will also include a no-amendment control. All the amendments will be added at three different loading rates, allowing us to test three hypotheses: 1) Amendments will result in increased gas flux due to the addition of soluble C and N and flux will increase linearly with loading rate; 2) Nitrous oxide and methane flux will be higher when sawdust and compost are added, compared to no amendment or BLOOM(TM); and 3) Amendments will encourage the growth of denitrifying bacteria more than iron-reducing bacteria. These experiments will establish methodology and provide initial data to complement a planned field experiment. Currently the Principal Investigators are awaiting a decision by Maryland State Highway Administration (SHA) to fund a field study using similar amendments in a mitigation project that is set to begin in 2017. The lab experiments will complement this field experiment by confirming the short-term impact of amendments on biogeochemical cycling and microbial composition. The proposal includes two letters of support, one from our contact at SHA and a second from a representative of DC Water and Sewer Authority agreeing to provide BLOOM(TM). This proposed research will impact efforts to improve Maryland’s water resources. Water quality will be improved through testing amendments meant to improve wetland function and jump-start the microbial community. We will train two graduate students and two undergraduates and will report our findings to SHA, DC Water, and to the broader scientific community. Additionally, we plan to publish at least one scientific paper.