Productivity and Nutrient Values of Plants Growing in the Salt Marshes of the Town of Hempstead, Long Island

The abundance and chemical composition of marsh grasses, sea lettuce and phytoplankton were determined in the Hempstead Bay estuary of the Town of Hempstead, Long Island, New York in 1967. The marshland comprises about 6,700 acres and the aquatic environment some 11,500 acres. Species of marsh grasses belonging in the genera Spartina and Distichlis produce an estimated 17,113 tons of dry matter per year in the Hempstead estuary, while the acquatic sea lettuce and phytoplankton produce 21,955 tons. The primary producers of organic matter in the Hempstead estuary are shown to form valuable quantities of protein, fat, carbohydrates and vitamins. Protein content of marsh grasses ranged from 9.6% to 14.9% of dry weight. Zostera yielded 14.6% and Ulva 20.8% protein in the dry matter. In the species of Ulva, Zostera, Spartina and Distichlis, ash content varied from 5.5% to 58.2%, fat ranged from 0.5% to 2.9% and carbohydrate yielded from 18.2% to 63.9%. Four B vitamins were present in adequate amounts to satisfy the requirements of grazing animals and microorganisms. Vitamin B12occurred in relatively small amounts, (0.008 to 0.022 microgm/gm) in the flowering plants, but Ulva yielded 0.26 microgm of B12per gram of dry matter. These nutrients and essential growth factors are available for direct assimilation by herbivores, and through microbial transformation to detritus they also supply indirectly valuable stores of particulate matter for filter feeders and other marine life.