Iron, nitrogen, phosphorus and zinc cycling and consequences for primary productivity in the oceans

John A. Raven, Karen Brown, Maggie Mackay, John Beardall, Mario Giordano, Espen Granum, Richard C. Leegood, Kieryn Kilminster, Diana I. Walker

    Research output: Chapter in Book/Report/Conference proceedingChapter

    18 Citations (Scopus)



    Primary productivity in the ocean amounts to the net assimilation of CO2 equivalent to about 50 Pg (petagram, i.e. 1015 g) C year-1, while on land this is approximately 60 Pg C year-1 (Field et al., 1998). Almost all of this primary productivity involves photosynthesis, and in the ocean it occurs only in the top few hundred metres, even in waters with the smallest light attenuation (Falkowski & Raven, 1997). About 1 Pg C of marine primary productivity involves benthic organisms, i.e. those growing on the substratum (Field et al., 1998), in the very small fraction of the ocean which is close enough to the surface to permit adequate photosynthetically active radiation (PAR) to allow photolithotrophic growth. This depth at which photosynthetic growth is just possible varies in time and space, and defines the bottom of the euphotic zone (Falkowski & Raven, 1997). The remaining ∼49 Pg C is assimilated by phytoplankton in the water column (Field et al., 1998). This chapter will concentrate on the planktonic realm, while acknowledging the importance of marine benthic primary producers and their interactions with micro-organisms (e.g. Dudley et al., 2001; Raven et al., 2002; Raven & Taylor, 2003; Cooke et al., 2004; Walker et al., 2004).

    The global net primary productivity of the oceans is less than that on land, despite about 70 % of the Earth being covered in ocean and primary productivity over considerable areas of land being limited by water supply.

    Original languageEnglish
    Title of host publicationMicro-organisms and earth systems - advances in geomicrobiology
    Subtitle of host publicationPublished for the Society for General Microbiology
    EditorsGeoff Gadd, Kirk Semple, Hilary Lappin-Scott
    PublisherCambridge University Press
    Number of pages26
    ISBN (Electronic)9780511754852
    ISBN (Print)9780521862226, 0521862221
    Publication statusPublished - 1 Jan 2005

    ASJC Scopus subject areas

    • Immunology and Microbiology(all)


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