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dc.contributor.authorDuhamel, Solange  Concept link
dc.contributor.authorBjörkman, Karin M.  Concept link
dc.contributor.authorRepeta, Daniel J.  Concept link
dc.contributor.authorKarl, David M.  Concept link
dc.date.accessioned2017-04-10T20:09:26Z
dc.date.available2017-04-10T20:09:26Z
dc.date.issued2016-12-29
dc.identifier.citationProgress in Oceanography 151 (2017): 261–274en_US
dc.identifier.urihttps://hdl.handle.net/1912/8884
dc.description© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Progress in Oceanography 151 (2017): 261–274, doi:10.1016/j.pocean.2016.12.007.en_US
dc.description.abstractThe southeast subtropical Pacific Ocean was sampled along a zonal transect between the coasts of Chile and Easter Island. This remote area of the world’s ocean presents strong gradients in physical (e.g., temperature, density and light), chemical (e.g., salinity and nutrient concentrations) and microbiological (e.g., cell abundances, biomass and specific growth rates) properties. The goal of this study was to describe the phosphorus (P) dynamics in three main ecosystems along this transect: the upwelling regime off the northern Chilean coast, the oligotrophic area associated with the southeast subtropical Pacific gyre and the transitional area in between these two biomes. We found that inorganic phosphate (Pi) concentrations were high and turnover times were long (>210 nmol l−1 and >31 d, respectively) in the upper water column, along the entire transect. Pi uptake rates in the gyre were low (euphotic layer integrated rates were 0.26 mmol m−2 d−1 in the gyre and 1.28 mmol m−2 d−1 in the upwelling region), yet not only driven by decreases in particle mass or cell abundance (particulate P- and cell- normalized Pi uptake rates in the euphotic layer were ∼1–4 times and ∼3–15 times lower in the gyre than in the upwelling, respectively). However these Pi uptake rates were at or near the maximum Pi uptake velocity (i.e., uptake rates in Pi amended samples were not significantly different from those at ambient concentration: 1.5 and 23.7 nmol l−1 d−1 at 50% PAR in the gyre and upwelling, respectively). Despite the apparent Pi replete conditions, selected dissolved organic P (DOP) compounds were readily hydrolyzed. Nucleotides were the most bioavailable of the DOP substrates tested. Microbes actively assimilated adenosine-5′-triphosphate (ATP) leading to Pi and adenosine incorporation as well as Pi release to the environment. The southeast subtropical Pacific Ocean is a Pi-sufficient environment, yet DOP hydrolytic processes are maintained and contribute to P-cycling across the wide range of environmental conditions present in this ecosystem.en_US
dc.description.sponsorshipFunds for this work were provided by the Gordon and Betty Moore Foundation’s Marine Microbiology Initiative (D.M.K., 3794) and the Center for Microbial Oceanography: Research and Education (C-MORE, National Science Foundation, D.M.K., EF0424599).en_US
dc.language.isoen_USen_US
dc.publisherElsevieren_US
dc.relation.urihttps://doi.org/10.1016/j.pocean.2016.12.007
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/*
dc.subjectPhosphorus dynamicsen_US
dc.subjectMicrobesen_US
dc.subjectStocksen_US
dc.subjectFluxesen_US
dc.subjectSoutheast subtropical Pacific Oceanen_US
dc.titlePhosphorus dynamics in biogeochemically distinct regions of the southeast subtropical Pacific Oceanen_US
dc.typeArticleen_US
dc.identifier.doi10.1016/j.pocean.2016.12.007


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