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Title: Global distribution and surface activity of macromolecules in offline simulations of marine organic chemistry

Here, organic macromolecules constitute high percentage components of remote sea spray. They enter the atmosphere through adsorption onto bubbles followed by bursting at the ocean surface, and go on to influence the chemistry of the fine mode aerosol. We present a global estimate of mixed-layer organic macromolecular distributions, driven by offline marine systems model output. The approach permits estimation of oceanic concentrations and bubble film surface coverages for several classes of organic compound. Mixed layer levels are computed from the output of a global ocean biogeochemistry model by relating the macromolecules to standard biogeochemical tracers. Steady state is assumed for labile forms, and for longer-lived components we rely on ratios to existing transported variables. Adsorption is then represented through conventional Langmuir isotherms, with equilibria deduced from laboratory analogs. Open water concentrations locally exceed one micromolar carbon for the total of protein, polysaccharide and refractory heteropolycondensate. The shorter-lived lipids remain confined to regions of strong biological activity. Results are evaluated against available measurements for all compound types, and agreement is generally quite reasonable. Global distributions are further estimated for both fractional coverage of bubble films at the air-water interface and the two-dimensional concentration excess. Overall, we show that macromolecular mapping providesmore » a novel tool for the comprehension of oceanic surfactant distributions. Results may prove useful in planning field experiments and assessing the potential response of surface chemical behaviors to global change.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [6] ;  [7] ;  [3] ;  [1]
  1. New Mexico Institute of Mining and Technology, Socorro, NM (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Scripps Institution of Oceanography, La Jolla, CA (United States); Univ. of California, Berkeley, CA (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  6. Univ. of California, Irvine, CA (United States)
  7. Scripps Institution of Oceanography, La Jolla, CA (United States)
Publication Date:
OSTI Identifier:
1229982
Report Number(s):
PNNL-SA--106391
Journal ID: ISSN 0168-2563; KP1703020
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
Biogeochemistry
Additional Journal Information:
Journal Volume: 126; Journal Issue: 1; Journal ID: ISSN 0168-2563
Publisher:
Springer
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY organic macromolecules; mixed layer distributions; Langmuir adsorption; fractional coverage; bubble films; air-water interface