Enhanced new production observed from the diurnal cycle of nitrate in an oligotrophic anticyclonic eddy

Zhang, Jiazhong; Wanninkhof, Rik; Lee, Kitack

doi:10.1029/2000gl012065

Cited by 49 publications

(41 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…, 1997). The eddy habitat produces locally elevated chlorophyll and zooplankton abundance, and mechanically affects local aggregation of prey organisms (Owen, 1981; Zhang et al. , 2001), and thereby stimulates feeding conditions (Logerwell and Smith, 2001).…”

Section: Discussionmentioning

confidence: 99%

Albacore (Thunnus alalunga) fishing ground in relation to oceanographic conditions in the western North Pacific Ocean using remotely sensed satellite data

Zainuddin

Saitoh²,

Saitoh

2008

Fisheries Oceanography

147

113

View full text Add to dashboard Cite

Satellite-based oceanographic data of sea surface temperature (SST), sea surface chlorophyll-a concentration (SSC), and sea surface height anomaly (SSHA) together with catch data were used to investigate the relationship between albacore fishing ground and oceanographic conditions and also to predict potential habitats for albacore in the western North Pacific Ocean. Empirical cumulative distribution function and high catch data analyses were used to calculate preferred ranges of the three oceanographic conditions. Results indicate that highest catch per unit efforts (CPUEs) corresponded with areas of SST 18.5-21.5°C, SSC 0.2-0.4 mg m )3 , and SSHA )5.0 to 32.2 cm during the winter in the period 1998-2000. We used these ranges to generate a simple prediction map for detecting potential fishing grounds. Statistically, to predict spatial patterns of potential albacore habitats, we applied a combined generalized additive model (GAM) ⁄ generalized linear model (GLM). To build our model, we first constructed a GAM as an exploratory tool to identify the functional relationships between the environmental variables and CPUE; we then made parameters out of these relationships using the GLM to generate a robust prediction tool. The areas of highest CPUEs predicted by the models were consistent with the potential habitats on the simple prediction map and observation data, suggesting that the dynamics of ocean eddies (November 1998 and2000) and fronts (November 1999) may account for the spatial patterns of highest albacore catch rates predicted in the study area. The results also suggest that multispectrum satellite data can provide useful information to characterize and predict potential tuna habitats.

show abstract

Section: Discussionmentioning

confidence: 99%

Albacore (Thunnus alalunga) fishing ground in relation to oceanographic conditions in the western North Pacific Ocean using remotely sensed satellite data

Zainuddin

Saitoh²,

Saitoh

2008

Fisheries Oceanography

147

113

View full text Add to dashboard Cite

show abstract

“…The mixed layer reduction in nC T was then corrected for the C T difference in the ratio of C T flux and that calculated using the concurrent flux of NO 3 − multiplied by a C:N ratio of 7 (Table S1). During the warming period, the mixed layer generally shoals but intermittent entrainment (e.g., caused by eddies and storms) also occurs due to short periods of wind‐induced mixed layer deepening (McGillicuddy et al, ; Zhang et al, ). The effect of the entrainment process on the mixed layer nC T budget would be similar to that of the diffusive flux.…”

Section: Computation Methodsmentioning

confidence: 99%

Carbon‐Based Estimate of Nitrogen Fixation‐Derived Net Community Production in N‐Depleted Ocean Gyres

Lee

Takahashi

et al. 2018

Global Biogeochemical Cycles

Self Cite

View full text Add to dashboard Cite

Accurate estimation of net community production (NCP) in the ocean is important for determining the future trend for carbon dioxide concentrations in the atmosphere and thus for understanding the global carbon cycle and climate change. Most methods for measuring NCP rely on analysis of dissolved fixed inorganic nitrogen species (N), which are believed to be limiting factors for NCP. However, in the vast areas of the ocean gyres only low levels of N are available for phytoplankton during much of the year. In this study the NCP was estimated by summing the seasonal reduction in the concentration of dissolved inorganic carbon (CT) in the surface mixed layer, corrected for changes associated with salinity variation, net air‐sea CO2 flux, horizontal C advection, non‐Redfield diffusive C and N fluxes (deviations from the C:N ratio of 7), and anthropogenic nitrogen deposition. The mixed layer reduction in CT was calculated from an annual CT cycle, deduced from comprehensive records of surface pCO2 and total alkalinity, using an established thermodynamic model. This method yielded a value of 0.6 ± 0.2 Pg of C, which represents the NCP that occurred during the warming period (approximately 8 months) in the nitrate‐depleted (<0.2 μmol/kg) ocean. Our estimate is broadly consistent with the global N2 fixation rate estimated using the 15N‐based method and suggests that N2 fixation by microorganisms is a major driver for this NCP.

show abstract

“…

{NH}_{4}^{+}

{NO}_{3}^{-}

and

{NO}_{2}^{-}

of culture samples were analyzed following the manual procedure of Hansen and Koroleff (). The

{NO}_{3}^{-}

content was analyzed using a cadmium column (Lachat, Wisconsin, U.S.A.); during our sample analyses the reduction efficiency of the column was maintained at 95% or higher, which met the performance level recommended for the column (Zhang et al ). No

{NH}_{4}^{+}

was detected.…”

Section: Methodsmentioning

confidence: 99%

Organic alkalinity produced by phytoplankton and its effect on the computation of ocean carbon parameters

Lee

Eom

et al. 2016

Limnology & Oceanography

Self Cite

View full text Add to dashboard Cite

In seawater dissolved organic acids produced by phytoplankton dissociate into conjugate bases and an amount of hydrogen ions that maintain electroneutrality, leaving the seawater alkalinity (AT) unchanged. However, the resulting conjugate bases react with protons during seawater titration and thereby contribute to the titration alkalinity (AT−ORG) whereas the contributions of other species (e.g., CO32−, B(OH)4−) to AT are proportionally lowered. Production of such dissolved organic acids was confirmed in each of six phytoplankton cultures and in a coastal environment. In phytoplankton monocultures with initial concentrations of ∼70 μM nitrate and ∼5 μM phosphate, the contribution of organic acids to the seawater alkalinity (AT−ORG) was found to be 15−40 μmol kg−1 on the complete consumption of added nutrients, with the magnitude of AT−ORG depending on the phytoplankton species involved. In the coastal environment the contribution of AT−ORG was as high as 15 μmol kg−1. Analysis of back titration data of culture and coastal samples further enabled identification of the functional groups responsible, which included two distinct charge groups (pKa1 = 4.4−4.9; pKa2 = 6.1−6.9). Thus, if the effect of organic acids on seawater AT is not accounted for, the concentrations of inorganic carbon components calculated from pairs of carbon parameters, including AT, will be inaccurate in culture studies and in studies of productive coastal environments.

show abstract

Enhanced new production observed from the diurnal cycle of nitrate in an oligotrophic anticyclonic eddy

Cited by 49 publications

References 26 publications

Albacore (Thunnus alalunga) fishing ground in relation to oceanographic conditions in the western North Pacific Ocean using remotely sensed satellite data

Albacore (Thunnus alalunga) fishing ground in relation to oceanographic conditions in the western North Pacific Ocean using remotely sensed satellite data

Carbon‐Based Estimate of Nitrogen Fixation‐Derived Net Community Production in N‐Depleted Ocean Gyres

Organic alkalinity produced by phytoplankton and its effect on the computation of ocean carbon parameters

Contact Info

Product

Resources

About