Organic Signatures of Surfactants and Organic Molecules in Surface Microlayer and Subsurface Water of Delaware Bay
Date
2022-12-15
Journal Title
Journal ISSN
Volume Title
Publisher
ACS Earth and Space Chemistry
Abstract
Surface-active species are present in marine waters and can accumulate in the surface microlayer (SML). Surfactants are amphiphilic organic compounds that reduce surface tension at an interface. Current work is investigating the link between the molecular composition of surfactants in the SML and those in subsurface waters, as well as the differences in surfactant molecular composition across different water types. In this study, subsurface water and SML samples were collected on three sampling days at three sites in the Delaware Bay: the Mouth of the Bay, Mid-Bay, and the marsh-influenced Broadkill River. Organic matter was extracted from the SML and subsurface water using two solid-phase extractions (graphitized carbon and C18) and then analyzed using tensiometry and high-resolution mass spectrometry, in positive and negative ionization modes. Here, we show that molecules with high H/C are preferentially enriched in the SML compared to the subsurface waters. We demonstrate that the measured organic extracts contribute to lower surface tensions in the SML. A rainfall event led to increased terrestrial runoff and mixing that altered the composition of the organic molecules in the SML and subsurface waters of the Broadkill River site, and the composition of the extracted organic molecules varied across sampling days. These results imply that the surfactant compositions are not uniform across sampling regions or from the subsurface to the SML.
Description
This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Earth and Space Chemistry, copyright © 2022 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsearthspacechem.2c00220. This article will be embargoed until 12/15/2023.
Keywords
microlayer, surfactants, mass spectrometry, surface tension, Delaware Bay, estuarine water
Citation
Burdette, Tret C., Rachel L. Bramblett, Ariana M. Deegan, Nicole R. Coffey, Andrew S. Wozniak, and Amanda A. Frossard. “Organic Signatures of Surfactants and Organic Molecules in Surface Microlayer and Subsurface Water of Delaware Bay.” ACS Earth and Space Chemistry 6, no. 12 (December 15, 2022): 2929–43. https://doi.org/10.1021/acsearthspacechem.2c00220.