Partial characterization of the dissolved organic phosphorus pool in the oligotrophic North Pacific Ocean

Karl, David M.; Yanagi, Katsumi

doi:10.4319/lo.1997.42.6.1398

Cited by 102 publications

(110 citation statements)

References 42 publications

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“…ALOHA by a variable amount (Thomson-Bulldis and Karl, 1998). For this reason we retain the designation`soluble reactive phosphorusa throughout this paper as an operational de"nition for the dissolved P pool that includes both Pi and certain uncharacterized organic compounds (Karl and Yanagi, 1997).…”

Section: Methodsmentioning

confidence: 99%

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Ecological nitrogen-to-phosphorus stoichiometry at station ALOHA

Karl

Björkman

Dore³

et al. 2001

Deep Sea Research Part II: Topical Studies in Oceanography

297

240

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The elemental stoichiometry of dissolved and particulate matter in the sea, especially the nitrogen-tophosphorus ratio, is an important parameter for studies of the nutrient control of plankton growth and for modeling biogeochemical processes, including carbon sequestration. Nitrogen (N) and phosphorus (P) pools have been measured on approximately monthly intervals for a 9-yr period at a deep-ocean station in the North Paci"c subtropical gyre (Sta. ALOHA; 22345N, 1583W). These data sets reveal complex interactions between N and P pools, and several unexpected secular trends. Models based on steady-state assumptions will not capture these temporal variations, especially the apparently rapid response of the microbial assemblages to stochastic nutrient intrusion events and the time-varying (seasonal, interannual and decadal scale) changes in dissolved matter N : P ratios. Based on an analysis of these data, we hypothesize that the gyre is presently in a period of net "xed N sequestration and P control of plankton rate processes.

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Section: Methodsmentioning

confidence: 99%

“…However, these UV-refractory compounds are apparently not a signi"cant portion of TDP in seawater samples collected at Sta. ALOHA (Karl and Yanagi, 1997). Independent TDP estimation using high-temperature persulfate digestion methods indicates that the two methods return similar TDP estimates when replicate Sta.…”

Section: Methodsmentioning

confidence: 99%

Ecological nitrogen-to-phosphorus stoichiometry at station ALOHA

Karl

Björkman

Dore³

et al. 2001

Deep Sea Research Part II: Topical Studies in Oceanography

297

240

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“…The exposure time of the water sample to the UV ray was 20 min. Details of the UV irradiation instrument have been described elsewhere [Yanagi et al, 1992;Karl and Yanagi, 1997;Lee et al, 2008].…”

Section: Uv Irradiationmentioning

confidence: 99%

“…The method has successfully subdivided SNP into UV labile (mainly composed of monophosphate esters) and UV stable (nucleotide diphosphates and triphosphates, nucleic acids and other resistant compounds) fractions. The seasonal variations in the concentration of UV labile and UV stable fractions of SNP were determined in the oligotrophic subtropical eastern [Karl and Yanagi, 1997] and western [Lee et al, 2008] North Pacific, and their results showed different seasonal variability and biogeochemical properties in each fraction. In this study, we attempted to understand the seasonality and biogeochemical properties in the subdivided organic pools by the same UV irradiation method used for the SNP.…”

Section: Introductionmentioning

confidence: 99%

“…To elucidate the biogeochemical properties of TOC that accumulated in the upper layer in warm seasons, we divided TOC into two fractions depending on their reactivity to the specific UV irradiation. Yanagi et al [1992] and Karl and Yanagi [1997] proposed a partial photochemical oxidation method that uses a UV irradiation apparatus specifically designed to characterize the dissolved organic phosphorus (DOP) pool to fractionate soluble nonreactive phosphorus (SNP) in oceanic environments. The method has successfully subdivided SNP into UV labile (mainly composed of monophosphate esters) and UV stable (nucleotide diphosphates and triphosphates, nucleic acids and other resistant compounds) fractions.…”

Section: Introductionmentioning

confidence: 99%

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Concentration and UV reactivity of total organic carbon in the upper layer in the oligotrophic subtropical western North Pacific

Sangkyun¹,

Hama²,

Ishii³

et al. 2010

J. Geophys. Res.

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[1] Characteristics of temporal variation in the vertical profile of total organic carbon (TOC) were investigated in the upper layer of the ocean at various latitudes (10-30°N) of 137°E in the western North Pacific subtropical gyre. Bulk TOC was divided into labile and stable fractions by the specific UV irradiation to evaluate their contributions to the temporal fluctuation of TOC. Authentic specimens and dissolved organic carbon collected from coastal waters were used to examine the correspondence between the photochemical reactivity to the specific UV irradiation and biological reactivity. The concentration of TOC in the upper layer was higher in summer when the surface layer is well stratified and was lower in winter when the mixed layer deepened. Although the winter mixed layer is shallower in lower latitudes, the amplitude of the seasonal variations in the top 50 m weighted mean TOC concentration (19.5-27.7 mM) did not vary considerably over the subtropical zones we studied. A major fraction (51.9-89.8%) of TOC was stable against specific UV irradiation and was thought to be mainly composed of biologically stable organic compounds, but the seasonal variation of TOC at each latitude was mainly attributable to the variation of UV labile fraction. This finding suggests that the seasonal variation of TOC in the upper layer is explained by the biological production of TOC in summer surface water and its vertical mixing with low UV, labile TOC in winter. Upward advection of subsurface water due to the passage of cyclonic eddies and changes in the geostrophic current are also likely to affect the temporal TOC variation, in particular, in the lower latitudes where winter mixed layer and permanent thermocline are shallower.

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Promotion Effect of Asian Dust on Phytoplankton Growth and Potential Dissolved Organic Phosphorus Utilization in the South China Sea

et al. 2018

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Dust deposition is an important nutrient source to the South China Sea (SCS), but few in situ experiments were conducted on phytoplankton response to the deposition. We conducted onboard incubation experiments at three stations near Luzon Strait in the SCS, with addition of multiple dissolved inorganic nutrients, Asian dust, and rainwater. From our results, nitrogen and phosphorus were both urgently needed for phytoplankton growth in the SCS, indicated by the evident Chl a response to the addition of nitrogen and phosphorus together. Almost no evident response was observed by adding phosphorus or iron alone to incubation waters, although a delayed response of Chl a in mass concentration was observed by adding nitrogen alone. The latter implied a possible utilization of dissolved organic phosphorus because of insufficient dissolved inorganic phosphorus in incubation waters. Under such nutrient condition, Asian dust showed an apparent promotion effect on phytoplankton growth by providing sufficient amounts of nitrogen but low phosphorus. Meanwhile, it was found that large sized (> 5 μm) phytoplankton community showed different responses to dust addition at different stations. At stations A3 and A6, Chaetoceros spp. became the dominant species during the bloom period, while at station WG2, Nitzschia spp. became dominant. In combination with different initial nutrients and Chl a levels at the three stations, the different phytoplankton community evolution implied the response difference to external inputs between oligotrophic (stations A3 and A6) and ultraoligotrophic (station WG2) conditions in the SCS.

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Partial characterization of the dissolved organic phosphorus pool in the oligotrophic North Pacific Ocean

Cited by 102 publications

References 42 publications

Ecological nitrogen-to-phosphorus stoichiometry at station ALOHA

Ecological nitrogen-to-phosphorus stoichiometry at station ALOHA

Concentration and UV reactivity of total organic carbon in the upper layer in the oligotrophic subtropical western North Pacific

Promotion Effect of Asian Dust on Phytoplankton Growth and Potential Dissolved Organic Phosphorus Utilization in the South China Sea

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