The Effect of Climate Change Induced Flooding on Soil Biogeochemical Properties in a Coastal Ecosystem.

Until recently, extensive flooding along the East Coast of the U.S. was typically the result of a large storm event, but changes in climate have caused an increase in coastal flooding in both duration and extent that may leave coastal soils vulnerable. Although there have been advances in climate change research, there is still a need for more high-resolution data on the interconnection between soil biogeochemical properties and nutrient dynamics between terrestrial and aquatic systems. To better understand this relationship, a flood-simulation study was conducted to determine the effect of saltwater inundation on soil biogeochemical properties and nutrient flux (TP, TKN, NH₄, and NOx) across different coastal ecosystems: submerged, marsh, upland forest, residential lawn, and agriculture row crop. To illustrate the effect of saltwater on nutrient response, soil cores were selected to be flooded with either de-ionized freshwater or full strength seawater. The results show that flooding with seawater produces the biggest response from the typically dry inland soils in the upland forest, residential lawn and agriculture ecosystems by significantly increasing soil EC, as well as causing the largest TP and TN flux from their soils. This study lays the groundwork for the importance of exploring the effects of inundation on soils as coastal flooding is becoming more frequent, and a rise in sea level is leaving more inland communities susceptible to flooding conditions. Moving forward, further analysis of background soil biogeochemical properties (pH, EC, Eh, etc.) will be evaluated as potential indicators of the expected nutrient response to a flooding event to be applied across different coastal ecosystems.