Groundwater-dependent ecosystems face a greater threat of pollution. In many cases groundwater can become polluted through toxins, or even just excessive amounts of certain nutrients seeping down to the water table. This polluting of the groundwater can have many different effects on the related ecosystems in the case of an estuary in Cape Cod it was noted that an influx of new nitrogen had come from septic tank fields in the groundwater’s flow path. Increased levels of nitrogen in aquatic ecosystems can cause eutrophication which is the process of excessive introduction of nutrients causing an abundance of plant growth which can result
Eutrophication those levels, so they can be overgrown by faster growing and more competitive species. In meadows, tall grasses that can take advantage of higher nitrogen levels may change the area so that natural species may be lost. Species-rich fens can be overtaken by reed or reedgrass species. Forest undergrowth affected by run-off from a nearby fertilized field can be turned into a nettle and bramble thicket. Chemical forms of nitrogen are most often of concern with regard to eutrophication, because plants have high nitrogen requirements so that additions of nitrogen compounds will stimulate plant growth. Nitrogen is not readily available