The Cretaceous-Paleogene (K-Pg) mass extinction provides a natural experiment in processes of extinction and recovery, as it is the most recent and well studied of the five major mass extinctions. The K-Pg extinction was triggered by the Chicxulub impact [e.g., Bralower et al., 2010; Miller et al., 2010; Schulte et al., 2010] and is thought to have precipitated a sudden decrease in primary and/or export productivity in the global ocean [Hsü et al., 1982b; Zachos et al., 1989; D'Hondt et al., 1998]. A decrease in organic matter export from the surface ocean is indicated by the collapse of surface-to-deep water δ13C gradients in carbonates, a sharp decrease in biogenic sedimentation rates, and improved carbonate preservation [Hsü et al., 1982a; Stott and Kennett, 1989; Zachos et al., 1989; D'Hondt, 2005]. In the aftermath of the K-Pg extinction, the recovery to preimpact levels of surface-to-deep δ13C gradients coincided with the rediversification of planktonic foraminiferal species richness [Coxall et al., 2006]. This diversity-δ13C correlation is striking, and has been interpreted to suggest that stable, species-rich ocean ecosystems are either necessary for and/or dependent on relatively high export production [D'Hondt et al., 1998; Coxall et al., 2006].
 There have been two primary hypotheses to explain the productivity change associated with the mass extinction. An early model was the Strangelove Ocean Hypothesis, which postulated the near complete cessation [Hsü et al., 1982b; Hsü and McKenzie, 1985] or reduction [Zachos et al., 1989] of primary productivity in the surface ocean leading to reduced export of organic matter to the deep ocean. Carbon cycle modeling showed that it was not necessary for productivity to stop entirely to explain the loss of surface-to-deep δ13C gradients; a 10% reduction in the efficiency of the biological pump sufficed [Kump, 1991]. More recently, D'Hondt et al.  suggested that primary productivity was nearly unchanged by the extinction, but the replacement of large grazers by microbially dominated communities in the surface ocean drastically reduced the export of production to the seafloor. This hypothesis of a dominant microbial food loop has been called “The Living Ocean Hypothesis” [D'Hondt et al., 1998; D'Hondt, 2005] because it posits a shift in the way organic production is recycled rather than the reduction of oceanic primary productivity.
 Both the Living Ocean hypothesis and Strangelove Ocean hypothesis assume that a prolonged (3–4 million years) global decline in export production is responsible for collapsed surface-to-deep δ13C gradients [Hsü and McKenzie, 1985; Zachos et al., 1989; D'Hondt et al., 1998; D'Hondt, 2005]. It is therefore surprising that benthic foraminifera did not suffer a mass extinction at the K-Pg boundary [Culver, 2003]. Benthic communities are largely dependent on the flux of organic matter from the pelagic realm [Gooday, 2003], and the lack of extinction in benthic species is paradoxical in light of an apparent global decrease in food supply [Thomas, 2007]. Many benthic foraminiferal communities do appear to have experienced a period of altered community composition across the K-Pg boundary, suggestive of a decrease in the local food supply [Widmark and Malmgren, 1992; Culver, 2003; Alegret and Thomas, 2005]. Surprisingly, this is not true everywhere. At some locales (Figure 1) benthic foraminiferal community structure suggests robust or even increased organic fluxes across the K-Pg boundary [Alegret and Thomas, 2009], even in cases where δ13C gradients or sedimentation rates suggest reduced export production. In these locations, robust export productivity to the deep sea suggested by both the lack of species extinctions and the structure of benthic foraminiferal communities directly conflicts with the Living Ocean hypothesis and the standard interpretation of collapsed δ13C gradients. Thus, hypotheses for the apparent pelagic-benthic decoupling across the K-Pg boundary include weaker bentho-pelagic coupling in warmer seas (Thomas et al. , although later discounted by Thomas ), a more rapid recovery of export productivity from the end-Cretaceous mass extinction than indicated by δ13C gradients [Thomas, 2007], and/or the regional maintenance of preextinction levels of export productivity [Alegret and Thomas, 2009]. The last two mechanism require that the collapse and recovery of δ13C gradients and other carbonate proxies primarily record processes other than a reduction in the amount of export productivity during this time interval [Thomas, 2007], and calls into question inferred changes in export productivity across the K-Pg boundary based on carbonate proxies alone.
 Other export productivity proxies have also indicated the maintenance or rapid rebound of organic fluxes after the extinction providing some support for the benthic foraminiferal patterns. For example, siliceous sediments are commonly associated with productive regions of the ocean so it is notable that New Zealand sites had siliceous blooms through the first million years of the Paleocene, with an order of magnitude increase in diatom to radiolarian (primary producer: consumer) ratios and a conspicuous lack of radiolarian extinctions [Hollis et al., 1995]. New Zealand sites also record an increase in “biogenic” barium (associated with sinking organic matter) accompanying the siliceous blooms [Hollis et al., 2003]. In addition, geochemical export productivity proxies including reactive phosphorus and organic carbon content did not decline at the K-Pg boundary at one upwelling site in the western North Atlantic (Blake Nose) [Faul et al., 2003], although the δ13C gradient collapsed [Quillévéré et al., 2008]. Finally, a very high resolution record of biomarkers (biodegradation resistant sterane and hopane ratios) and δ13Corganic and δ15Norganic from the Fish Clay, Denmark, detail the initial decline and rapid recovery to preboundary levels of algal export productivity and community composition within 100 years of the impact [Sepulveda et al., 2009].
 Here, we seek to resolve the paradox of conflicting effects of the K-Pg boundary on global surface ocean export productivity as recorded in carbonate productivity proxies (surface-to-deep water δ13C gradients, sedimentation rates, and carbonate preservation) and noncarbonate productivity proxies (benthic foraminiferal community structure, biomarkers, and other geochemical proxies like biogenic barium and organic carbon content). We estimate the relative change in export productivity in multiple ocean basins using biogenic barium. Biogenic barium (Babio) is a widely used productivity proxy that correlates well with modern export production [Dymond et al., 1992; Francois et al., 1995; Eagle et al., 2003] and has been used to trace changes in Cenozoic productivity [e.g., Paytan et al., 1996; Thompson and Schmitz, 1997; Bains et al., 2000; Griffith et al., 2010]. We compare our export productivity records to existing carbonate and noncarbonate paleoproductivity proxy records to test the spatial extent of the Living Ocean Hypothesis.