Sequential injection analysis of nanomolar soluble reactive phosphorus in seawater with HLB solid phase extraction

Ma, Jian; Yuan, Dongxing; Liang, Ying

doi:10.1016/j.marchem.2008.04.011

Cited by 51 publications

(40 citation statements)

References 28 publications

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“…The linear working range we used was 0. We also measured DIP at nmol L 21 levels according to Ma et al (2008). Briefly, DIP was first extracted using a solid phase cartridge (Waters Oasis) by forming phosphomolybdenum blue, then eluted with sodium hydroxide solution.…”

Section: Methodsmentioning

confidence: 99%

Nutrient dynamics and biological consumption in a large continental shelf system under the influence of both a river plume and coastal upwelling

Han

Dai

Kao

et al. 2012

Limnology & Oceanography

188

181

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We examined the dynamics of dissolved inorganic nitrogen (DIN, nitrate + nitrite), dissolved inorganic phosphorus (DIP), and silicate (Si(OH) 4 ) in the northern shelf of the South China Sea in summer, which is under a complex hydrodynamic scheme largely shaped by river plume and coastal upwelling, along with the enhanced biological consumption of nutrients therein. The Pearl River plume, with high nutrient concentrations (, 0.1-14.2 mmol L 21 for DIN, , 0.02-0.10 mmol L 21 for DIP, and , 0.2-18.9 mmol L 21 for Si(OH) 4 ), occupied a large area of the middle shelf (salinity , 33.5). The nearshore area had high nutrient concentrations apparently sourced from subsurface nutrient-replete waters through wind-driven coastal upwelling. These nutrient levels were significantly elevated relative to those on the oligotrophic outer shelf where DIN, DIP, and Si(OH) 4 concentrations dropped to , 0.1 mmol L 21 , , 0.02-0.03 mmol L 21, and , 2.0 mmol L 21, respectively. A three end-member mixing model was constructed based on potential temperature and salinity conservation to assess biological consumption of inorganic nutrients, which was denoted by D and defined by the deviation from conservative mixing. In the coastal upwelling zone and deep chlorophyll maximum layer, the nutrient uptake ratio DDIN : DDIP was 16.7, which is the classic Redfield ratio. In contrast, in the river plume the uptake ratio was 61.3 6 8.7. We believed that an alternative non-DIP source likely contributed to this higher DIN : DIP consumption ratio in the river plume regime. Meanwhile, Si(OH) 4 showed predominant consumption in the river plume and a combination of regeneration and consumption along the path of the coastal upwelling current.

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Section: Methodsmentioning

confidence: 99%

Nutrient dynamics and biological consumption in a large continental shelf system under the influence of both a river plume and coastal upwelling

Han

Dai

Kao

et al. 2012

Limnology & Oceanography

188

181

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“…Nanomolar levels of soluble reactive phosphorous (SRP) were determined according to Ma et al (2008) with a detection limit of 1.4 nM and relative precision of ±2.5 %. Nanomolar levels of nitrate were analyzed using the chemiluminescent method (Garside, 1982) with a detection limit of 2 nM.…”

Section: Seawater Sampling and Experimental Proceduresmentioning

confidence: 99%

Effect of light on N<sub>2</sub> fixation and net nitrogen release of <i>Trichodesmium</i> in a field study

et al. 2018

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Abstract. Dinitrogen fixation (NF) by marine cyanobacteria is an important pathway to replenish the oceanic bioavailable nitrogen inventory. Light is the key to modulating NF; however, field studies investigating the light response curve (NF-I curve) of NF rate and the effect of light on diazotrophderived nitrogen (DDN) net release are relatively sparse in the literature, hampering prediction using models. A dissolution method was applied using uncontaminated 15 N 2 gas to examine how the light changes may influence the NF intensity and DDN net release in the oligotrophic ocean. Experiments were conducted at stations with diazotrophs dominated by filamentous cyanobacterium Trichodesmium spp. in the western Pacific and the South China Sea. The effect of light on carbon fixation (CF) was measured in parallel using the 13 C tracer method specifically for a station characterized by Trichodesmium bloom. Both NF-I and CF-I curves showed a I k (light saturation coefficient) range of 193 to 315 µE m −2 s −1 , with light saturation at around 400 µE m −2 s −1 . The proportion of DDN net release ranged from ∼ 6 to ∼ 50 %, suggesting an increasing trend as the light intensity decreased. At the Trichodesmium bloom station, we found that the CF / NF ratio was light-dependent and the ratio started to increase as light was lower than the carbon compensation point of 200 µE m −2 s −1 . Under low-light stress, Trichodesmium physiologically preferred to allocate more energy for CF to alleviate the intensive carbon consumption by respiration; thus, there is a metabolism tradeoff between CF and NF pathways. Results showed that shortterm (< 24 h) light change modulates the physiological state, which subsequently determined the C / N metabolism and DDN net release by Trichodesmium. Reallocation of energy associated with the variation in light intensity would be helpful for prediction of the global biogeochemical cycle of N by models involving Trichodesmium blooms.

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“…Nutrient samples were analyzed on board the ship using routine spectrophotometric methods with a Technicon AA3 Auto-Analyzer (Bran-Lube, GmbH) (Han et al, 2012, and references therein). The nmol L −1 levels of PO 4 samples were frozen on board the ship and then measured in a shorebased laboratory following Ma et al (2008). Samples for chlorophyll a (Chl a) were filtered through 25 mm Whatman GF/F filters and then were immediately frozen until analysis.…”

Section: Sampling and Measurementsmentioning

confidence: 99%

Inter-shelf nutrient transport from the East China Sea as a major nutrient source supporting winter primary production on the northeast South China Sea shelf

et al. 2013

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Abstract. The East China Sea (ECS) and the South China Sea (SCS) are two major marginal seas of the North Pacific with distinct seasonal variations of primary productivity. Based upon field observations covering both the ECS and the northern SCS (NSCS) during December 2008-January 2009, we examined southward long-range transport of nutrients from the ECS to the northeastern SCS (NESCS) carried by the China Coastal Current (CCC) driven by the prevailing northeast monsoon in wintertime. These escaped nutrients from the ECS shelf, where primary production (PP) was limited in winter, might however refuel the PP on the NESCS shelf at lower latitude, where the water temperature remained favorable, but river-sourced nutrients were limited. By combining the field observation of nitrate+nitrite (NO 3 +NO 2 , DIN) with our best estimate of volume transport of the CCC, we derived a first-order estimate for DIN flux of 1430 ± 1024 mol s −1 . Under the assumption that DIN was the limiting nutrient, such southward DIN transport would have stimulated 8.84 ± 6.33 × 10 11 gC of new production (NP), accounting for 33-74 % of the NP or 14-22 % of PP in winter on the NESCS shelf shallower than 100 m.

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Sequential injection analysis of nanomolar soluble reactive phosphorus in seawater with HLB solid phase extraction

Cited by 51 publications

References 28 publications

Nutrient dynamics and biological consumption in a large continental shelf system under the influence of both a river plume and coastal upwelling

Nutrient dynamics and biological consumption in a large continental shelf system under the influence of both a river plume and coastal upwelling

Effect of light on N<sub>2</sub> fixation and net nitrogen release of <i>Trichodesmium</i> in a field study

Inter-shelf nutrient transport from the East China Sea as a major nutrient source supporting winter primary production on the northeast South China Sea shelf

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Sequential injection analysis of nanomolar soluble reactive phosphorus in seawater with HLB solid phase extraction

Cited by 51 publications

References 28 publications

Nutrient dynamics and biological consumption in a large continental shelf system under the influence of both a river plume and coastal upwelling

Nutrient dynamics and biological consumption in a large continental shelf system under the influence of both a river plume and coastal upwelling

Effect of light on N&lt;sub&gt;2&lt;/sub&gt; fixation and net nitrogen release of &lt;i&gt;Trichodesmium&lt;/i&gt; in a field study

Inter-shelf nutrient transport from the East China Sea as a major nutrient source supporting winter primary production on the northeast South China Sea shelf

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Effect of light on N<sub>2</sub> fixation and net nitrogen release of <i>Trichodesmium</i> in a field study