Simple equations to estimate ratios of new or export production to total production from satellite‐derived estimates of sea surface temperature and primary production

Abstract

Two simple equations with sea surface temperature and total primary production as independent variables were used to estimate ratios of new or export production to total primary production (ef-ratios) in the ocean. Both equations assume that ef-ratios are negatively correlated with temperature in a linear manner and positively correlated with total primary production in a curvilinear manner characteristic of a Holling type II function. The two equations were parameterized based on different sets of field data: in one case entirely from estimates of new production based on nitrate uptake, and in the other case based on a comprehensive summary of new and export production estimates derived from a combination of techniques. Estimates of global export production based on satellite observations and use of the two equations were 9-13 Gt C per year. The form of both equations likely captures the principal effects of temperature and total production on ef-ratios, and their mathematical simplicity should facilitate their prognostic application in climate change research and studies of the ocean's carbon cycle.

Strong contribution of diatom resting spores to deep-sea carbon transfer in naturally iron-fertilized waters downstream of South Georgia

“…Primary production downstream of subantarctic island systems is typically dominated by diatoms (Smetacek et al, 2004;Quéguiner, 2013), a microphytoplankton group generally considered to promote carbon export out of the mixed layer directly by sinking (Smetacek, 1985;Newton, 1995, 1999) or indirectly by sustaining faecal pellet-productive food webs (Smetacek et al, 2004;Manno et al, 2014). Maiti et al (2013) demonstrated an inverse relationship between primary production and export efficiency in the Southern Ocean, contrasting with the positive relationship between primary production and export prevailing in most of the global ocean (Laws et al, 2011). These so called high biomass, low export regimes (HBLE, Lam and Bishop, 2007;Lam et al, 2011) appear to be characterized by enhanced heterotrophic microbial activity Christaki et al, 2014) and intense reprocessing and fragmentation of particulate matter by zooplankton.…”

Export fluxes in a naturally iron-fertilized area of the Southern Ocean – Part 1: Seasonal dynamics of particulate organic carbon export from a moored sediment trap

“…Global estimates of particulate organic carbon (POC) export cluster between 5 Pg C yr −1 Lutz et al, 2007;Honjo et al, 2008;Henson et al, 2011;Lima et al, 2014) and 10 Pg C yr −1 (Laws et al, 2000;Schlitzer, 2004;Gehlen et al, 2006;Boyd and Trull, 2007;Dunne et al, 2007;Laws et al, 2011). The physical transfer of dissolved inorganic carbon to the ocean interior during subduction of water masses is 2 orders of magnitude higher (> 250 Pg C yr −1 ; Karleskind et al, 2011;Levy et al, 2013).…”

Global-scale variations of the ratios of carbon to phosphorus in exported marine organic matter

“…The spatial variability of (C:P) exp has important implications for the spatial pattern of annual net community production (ANCP). At present, satellite-derived estimates of ANCP are fairly uncertain, but tend to show values that are at least a factor of two lower in the subtropics compared to high latitudes 25,26 . In contrast to the satellitebased estimates and those of most global ocean biogeochemical models, the limited number of sites with experimental determinations of ANCP indicate less variation 10 .…”