Document Type


Publication Date


Subject: LCSH

Long Island Sound (N.Y. and Conn.); Sediments (Geology)


Biology | Ecology and Evolutionary Biology | Marine Biology


Total organic carbon, hydrogen, and nitrogen (CHN) analyses were performed on 147 surficial sediment samples from study areas off the Norwalk Islands and Milford, Connecticut, in western Long Island Sound. The CHN data and gross lithologic descriptions of the sediments are reported herein. The concentrations of total organic carbon (TOC), hydrogen, and nitrogen in these samples average 1.54, 1.40, and 0.17 weight percent, respectively. The individual CHN concentrations vary inversely with grain size, with CHN values increasing with the percent fines. Increasing nutrient inputs and decreasing circulation cause TOC and nitrogen values to generally increase westward within the Sound. C/N molar elemental ratios suggest that, except for the shoreward northwestern corner of the Norwalk Islands survey site, marine phytoplankton are probably the primary source of sedimentary organic matter in the study areas. Concentrations of the sedimentary organic matter are significantly higher in the spring than in the late summer, suggesting that these concentrations vary seasonally.

Publisher Citation

Poppe, L.J., Zajac, R., Lewis, R., Mlodzinska, Z., Pratt, S., Taylor, B.B. , and DiGiacomo-Cohen, M.L. (1996). Organic carbon, hydrogen, and nitrogen concentrations in surficial sediments from western Long Island Sound, Connecticut and New York. USGS Numbered Series 96-708. Denver, Colo. : U.S. Geological Survey.