An assessment of the effect of sea surface surfactant on global atmosphere‐ocean CO₂ flux

Abstract

[1] We assess the possible impact of the distribution of naturally occurring surfactants on the direct integration of the global atmosphere-ocean CO 2 flux across the ocean surface. The global atmosphere-ocean CO 2 flux is calculated using the monthly mean ÁpCO 2 climatology compiled by Takahashi et al. [1997] as well as satellite wind speed and seasurface temperature data. In the absence of any global map of surfactant coverage and as it is known that phytoplankton exudates and degradation products are the major sources of marine surfactants, ocean primary productivity, which can be derived from the satellitebased estimate of chlorophyll concentration, is used as an indicator of the presence of surfactants as proposed by Asher [1997]. From the calculated results it is found that suppression of the upward and downward CO 2 fluxes by marine surfactants exhibits an asymmetric effect: The average percent reduction of absorption flux by surfactants is about twice that of outgassing, which results in an overall decrease in the net global CO 2 uptake by the oceans. For almost half of the year (between January and May) the presence of surfactants does not affect CO 2 outgassing from global oceans. In contrast, throughout the entire year the presence of surfactants suppresses CO 2 absorption by the oceans. The major reduction in absorption fluxes occurs in the northern Pacific and Atlantic (10°N to 70°N) in all seasons and in the Southern Ocean (south of 40°S) in austral spring and summer. However, the most significant decrease in outgassing fluxes occurs in the equatorial and southern Pacific Ocean (40°S to 10°N), particularly in the eastern equatorial and subtropical waters off the southern American coast, in the period of austral spring and summer. Annual net CO 2 flux is reduced by approximately 20% under the surfactant coverage condition that the primary productivity is above a threshold value of 25 g-C m À2 mom À1 and by about 50% with a threshold of 15 g-C m À2 mom À1 .

Climate change impacts on sea–air fluxes of CO<sub>2</sub> in three Arctic seas: a sensitivity study using Earth observation

“…Goldman et al, 1988), especially in the Kara Sea given its large terrestrial freshwater supply. Although there are currently no data on the occurrence of biological surfactant in Arctic waters, there have previously been attempts to use EO data to infer open ocean distributions of surfactant (Liu et al, 2000;Lin et al, 2002) and the implications for gas exchange (Tsai and Liu, 2003). The latter authors used pCO 2 climatologies and EO derived estimates of U 10 , sea surface temperature and chlorophyll a to infer surfactant control on global air-sea CO 2 exchange.…”

Revealing structural properties of the marine nanolayer from vibrational sum frequency generation spectra

“…Results from studies of surfactants in the sea surface microlayer suggest that this interfacial layer covers the ocean to a significant extent and thus has a global impact on air-to-sea fluxes [Wurl et al, 2010;Tsai and Lui, 2003]. For reviews of the current knowledge of these features and past work we refer to the literature [Liss and Duce, 1997;Gladyshev, 2002;Gade et al, 2006].…”

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

“…Nonetheless progress has been steady -contrast the reviews by Liss (1975) and then Liss et al (1997) as an instructive set of examples. Highlights during this period of growth in the laboratory and seagoing effort have included the elucidation of bubble surface chemistry (Blanchard 1975(Blanchard , 1989, recognition of the importance of polymeric colloidal/gel processing (Wells and Goldberg 1993;Chin et al 1998), and transfer effects of films on sea-air gas fluxes (Frew et al 1990;Tsai and Liu 2003).…”