Contrasting effects of nutrient enrichment on below-ground biomass in coastal wetlands

Anthropogenically-enhanced nutrient availability is often cited among the most important drivers of altered ecosystem function and loss of services worldwide. Although the above-ground consequences of nutrient enrichment on plant growth patterns are numerous and well-documented, below-ground impacts are less clear but nonetheless critical from a global change perspective. In coastal wetlands, for example, plant-soil-nutrient dynamics directly affect the capacity to sequester carbon as soil organic matter, keep pace with sea level rise, and resist storm-induced erosion. Here, we investigate the effects of excess nutrient loading on below-ground plant growth in an oligohaline marsh fertilized for seven years with a factorial combination of nitrogen (N) and phosphorus (P). We used two common assessment procedures, the ingrowth and standing crop methods, to simultaneously quantify distinct aspects of below-ground plant growth: 1) below-ground biomass accumulation into unexploited open resou...