Isotopic fractionation of ammonium and nitrate during uptake by Skeletonema costatum: Implications for δ15N dynamics under bloom conditions, Jonathan Pennock, David J. Velinsky, John M. Ludlum, Jonathan H. Sharp, Marilyn L. Fogel
School of Marine Science and Ocean Engineering

Biogeochemical factors that influence the stable nitrogen isotope ratio of dissolved ammonium in the Delaware Estuary, Luis A. Cifuentes, Marilyn L. Fogel, Jonathan Pennock, Erin Hiley Sharp
School of Marine Science and Ocean Engineering

Determination of the isotopic composition of ammonium-nitrogen at the natural abundance level from estuarine waters, David J. Velinsky, Jonathan Pennock, Jonathan H. Sharp, Luis A. Cifuentes, Marilyn L. Fogel
School of Marine Science and Ocean Engineering