Researchers report the history of sediment deposition on marshes in New York City. Sea level rise, pollution, and upriver dams threaten urban coastal marshes worldwide. Effective restoration of these marshes requires an understanding of the history of marsh sediment deposition, including accretion rates and the relative contributions of organic and inorganic material. Using analysis of sediment cores, Dorothy Peteet and colleagues reconstructed three centuries of sedimentation history for marshes in Jamaica Bay, New York that have been disappearing at an accelerating rate in recent decades. The authors found that the flux of inorganic mineral sediments into the marshes has decreased dramatically since the beginning of the 19th century. The decrease likely resulted from urban development, stream loss, and dredging that resulted in loss of mineral sediment flux to the marshes. As the inorganic sediment flux decreased, organic flux sediment increased, possibly due to anthropogenic nitrogen pollution, so that total vertical accumulation outpaced sea level rise. However, the reduced mineral content of the sediment weakens the structure of the marshes. The results suggest that future marsh preservation will require addition of mineral sediment to dredged basins and borrow pits as well as to the marshes themselves, according to the authors.
Article #17-15392: "Sediment starvation destroys New York City marshes' resistance to sea level rise," by Dorothy M. Peteet et al.
MEDIA CONTACT: Dorothy M. Peteet, NASA Goddard Institute for Space Studies, New York, NY; tel: 845-642-5702; e-mail: firstname.lastname@example.org