Phosphate availability and the ultimate control of new nitrogen input by nitrogen fixation in the tropical Pacific Ocean

By T. Moutin, David M. Karl, S. Duhamel, P. Rimmelin, P. Raimbault, B. V. Mooy, H. Claustre. 2007

197 citations recorded by the source corpus.

Abstract. Due to the low atmospheric input of phosphate into the open ocean, it is one of the key nutrients that could ultimately control primary production and carbon export into the deep ocean. The observed trend over the last 20 years has shown a decrease in the dissolved inorganic phosphate (DIP) pool in the North Pacific gyre, which has been correlated to the increase in di-nitrogen (N2) fixation rates. Following a NW-SE transect, in the Southeast Pacific during the early austral summer (BIOSOPE cruise), we present data on DIP, dissolved organic phosphate (DOP) and particulate phosphate (PP) pools along with DIP turnover times (TDIP) and N2 fixation rates. We observed a decrease in DIP concentration from the edges to the centre of the gyre. Nevertheless the DIP concentrations remained above 100 nmol L−1 and T DIP was more than 6 months in the centre of the gyre; DIP availability remained largely above the level required for phosphate limitation to occur and the absence of Trichodesmium spp and low nitrogen fixation rates were likely to be controlled by other factors such as temperature or iron availability. This contrasts with recent observations in the North Pacific Ocean at the ALOHA station and in the western Pacific Ocean at the same latitude (DIAPALIS cruises) where lower DIP concentrations (

Subfields: Ecology, Oceanography

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Citations in the corpus

Dynamics of Dissolved Organic Phosphorus (2015, background): “…decadal-scale climate– ocean interactions (Karl, 1999), predicted oscillations in N-controlled versus P-controlled ecosystem dynamics (Karl, 2002), iron limitation of N2 fixation (Moutin et al., 2008), or the result of combined or independent processes is not known at the present time (Karl, 2014).”
Alkaline phosphatase activity and regulation in the North Pacific Subtropical Gyre (2010, background): “P availability in the ocean is considered to have a predominant role in controlling planktonic biomass and production (Karl et al. 2001; Van Wambeke et al. 2002; Moutin et al. 2008).”
Environmental control of open‐ocean phytoplankton groups: Now and in the future (2010, background): “…P additions in the southern subtropical Pacific Gyre, and Mackie et al. (2008) reported no response by Trichodesmium to the largest dust storm in 30 yr in subtropical southwest Pacific waters, which are characterized by very high phosphate concentrations, relative to nitrate (Moutin et al. 2008).”
Contribution of picoplankton to the total particulate organic carbon concentration in the eastern South Pacific (2007, background): “Here, the highestcp andcveg were associated with mature upwelling conditions characterized by the highest primary production (Moutin et al., 2007) and Tchla (Fig.”
Nutrient limitation of primary productivity in the Southeast Pacific (BIOSOPE cruise) (2007, background): “The scarcity of nitrogen fixing organisms in the South Pacific Gyre may be one of the origins of the relatively large phosphate concentrations (always above 0.11µmol l−1; Moutin et al., 2007), as well as the N controlled status of the phytoplankton and bacterial communities.”