The amount of living material produced when nutrients and energy from sunlight are used to create plant tissues, primary production has been shown to be higher in the estuarine ecotone than in the nutrient-poor upstream marshes of the Everglades due to mixing with phosphorus-rich marine waters. Scientists once thought that the presence of phosphorus-rich marine water in the estuarine ecotones was responsible for the high rates of productivity. They also thought that the Taylor Slough/Florida Bay estuarine ecotone would have reduced rates of productivity, or the amount of living material produced when nutrients and energy from sunlight are used to create plant tissues, compared to the Shark River Slough/Gulf of Mexico ecotone since Florida Bay’s low tidal action would inhibit marine phosphorus from entering the ecotone. Phase I of the FCE-LTER project investigated these hypotheses.

FCE-LTER scientists also examined patterns of organic matter – or nutrient-containing compounds derived from living things, such as plant debris – and its influence on productivity. They believed that increased freshwater flow, as a result of restoration projects, would increase the availability of organic matter, and thus increase productivity, as more of this material is carried downstream.