David, Mark B. 1983. Organic and inorganic sulfur cycling in forested and aquatic ecosystems in the Adirondack region of New York State. Ph.D. Dissertation, State University of New York, College of Environmental Science and Forestry, Syracuse, 268 pp.

Abstract: Sulfur constituents were measured in vegetation, soils, throughfall, soil solutions, streams, and lake waters of ecosystems within the Adirondack Mountain region of New York State. The flux of S constituents among and within these ecosystem components was also determined. The major study areas were hardwood and conifer terrestrial sites at the Huntington Forest and an acidic, lentic system (South Lake). Organic S predominated the forest Spodosol (Becket series) (C-bonded S was 50-80% and ester sulfate 10-25% of total S) with low concentrations of inorganic forms (sulfate and reduced non-sulfate inorganic S were 1-20% of total S). Carbon, N, and S relationships indicated the close coupling of S to organic C and N in these soils. Iron and Al sesquioxides were found in high concentrations in the mineral soils (up to 6% of total mass) and were important to sulfate absorption. Organic S constituents were found to be significant components of total S in solutions (throughfall and soil leachates). C-bonded S was 10-14% of total S in throughfall, 5-7% in O and A horizon leachates, and was not detected in B horizon solutions. Ester sulfate as a percent of total S was greatest in ) horizon solutions (11-20%) and decreased with depth.

Mos of the total S of the northern hardwood forest was found in the mineral soil (83%) with 5% in the forest floor and 7% in plant biomass. Of this total 69% was present as C-bonded S, 20% as ester sulfate, 7% as sulfate, and 4% as non-sulfate inorganic S. Estimated S mineralization for the ecosystem was greater than measured atmospheric inputs. This suggested that factors influencing mineralization-immobilization processes are important in evaluating S cycling and sulfate flux.

In the streams, water column, and inlets of South Lake organic S constituents were found to be 0-15% of total S. Seston S was comprised of ester sulfate (44-59% of total S), C-bonded S (32-43%), sulfate (10-16%), and non-sulfate inorganic S (1-2%). A S cycling budget for South Lake indicated that organic S deposition was the major input of S to the sediments.