Scaling of Marine Microlayer Film Surface Pressure-Area Isotherms Using ChemicalAttributes

摘要

Heterogeneity in the chemical composition of sea surface films due to variationin sources of surfactant materials and in physical dynamics during film formation may lead to spatial and temporal variability in interfacial physical properties. Alternatively, slick physical properties may be postulated to be largely averaged and therefore similar across a variety of oceanic regimes. In order to assess interslick variability in regimes of different productivity, surface pressure-area ( -A) isotherms have been measured for a suite of microlayers sampled at stations in productive coastal and mesotrophic waters of the southern California Bight. Surface-active organics isolated from the microlayers by solid phase extraction on C 18 Sep-Pak cartridges were respread on clean seawater, and the n-A isotherms of the reconstituted films were determined. Several bulk chemical parameters including dry weight, UV absorbance, and carbon, nitrogen, and lipid content have been examined in an attempt to scale the isotherms; the latter were shown not to collapse to a single well-constrained envelope when compared on a specific area basis. However, for several parameters there was a clear separation of the slicked microlayer isotherms into two distinct film types composed primarily of inshore and offshore samples, respectively.