A mysterious environmental changer: saltwater intrusion
Calibrating the pipette for 250 uL; the scale shows the weight of the DI water is exactly 0.0250 g!
When we appreciate the brilliant blue of the Chesapeake Bay, salted water silently invades lands that we live on due to global warming. This phenomenon is referred as saltwater intrusion (SWI), when saline water moves into fresh aquifers and surface water. New research is showing that SWI can disrupt nutrient cycling in coastal regions (Ardón et al 2013; Ardón et al 2017). In the Lower Eastern Shore of Maryland along the Chesapeake Bay, coastal farmland is subject to severe SWI and extensive agricultural areas will be lost in the coming decades (Shepard et al 2013). These coastal farmlands and adjacent areas (i.e. forests and marshes) provide important economic, social, and environmental functions in the region (Tully et al 2019).
Don’t worry, we researchers in AgroEcoLab, are here to investigate and solve this pressing problem! My work with Dani Weissman this semester is to further investigate the impact of saltwater intrusion on nutrients (i.e. nitrogen and phosphate) in active farm fields on the Lower Eastern Shore of Maryland. By reading all research papers provided by Dani, I learned that the saltwater includes rich ionic components (i.e. sulfate, sodium, etc.) that can bind to iron in soils stimulate the release of nutrients into soil porewater and surface water (Chambers and Odum 1990). It inspired me to develop an independent summer study on answering how the ionic components of saltwater affect nutrients in soils.
After two failed attempts, we finally got a nice standard curve on the colorimeter.
Thanks for this great opportunity offered by AgroEcoLab, I can experience working in a professional laboratory and apply my chemistry knowledge in practice. Until now, I have helped with sample preparation, experiment set-ups and data analysis. I still remembered the exciting moment when I obtained a perfect calibration for pipets (Figure 1); the cheerful moment when Dani and I finally resolved the instrumental issues (Figure 2). Participating in this saltwater intrusion projects not only provides me joys and self-fulfilling but also helps me develop professional research skills and enhances my understanding of environmental knowledge. My time in the AgroEcoLab is giving me an important foundation for me to attend graduate school in the future.
References:
Ardón M, Helton AM, Scheuerell MD, Bernhardt ES (2017) Fertilizer legacies meet saltwater incursion : challenges and constraints for coastal plain wetland restoration. Elementa: Science of the Anthropocene 5:41. doi:10.1525/elementa.236
Ardón M, Morse JL, Colman BP, Bernhardt ES (2013) Drought-induced saltwater incursion leads to increased wetland nitrogen export. Global Change Biology 19:2976–2985. doi:10.1111/gcb.12287
Chambers RM, Odum WE (1990) Porewater oxidation, dissolved phosphate and the iron curtain- Iron-phosphorus relations in tidal freshwater marshes. Biogeochemistry 10:37–52. doi:10.1007/BF00000891
Shepard A, Curson D, Patton K, Dubois N (2013) Sea-level Rise Is for the Birds: Landscape-level Conservation Planning to Protect Communities, Coastal Wetlands and Salt Marsh Birds. 20.
Tully KL, Weissman D, Wyner WJ, Miller J (2019) Soils in transition : saltwater intrusion alters soil chemistry in agricultural fields. Biogeochemistry. doi:10.1007/s10533-019-00538-9