The oceanic mixed-layer pump

Gardner, Wilford D.; Chung, Sung Pyo; Richardson, Mary Jo; Walsh, Ian D.

doi:10.1016/0967-0645(95)00037-q

Cited by 151 publications

(87 citation statements)

References 36 publications

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“…This is in the range of the value previously reported in the eastern Ionian sea (5-21 %, Oubelkheir and Sciandra, 2008) but remains lower than those documented for other areas (e.g. equatorial and tropical Pacific 25-70 %, Claustre et al, 1999;Durand and Olson, 1996;Gardner et al, 1995). Such diel changes in c p correspond to mean diurnal rate of variation (µ cp , in d −1 ) of 0.32 and 0.37 d −1 in stations A and B, respectively, estimated using the formulation proposed by Cullen et al (1992):…”

Section: Diel Cycle Insupporting

confidence: 50%

Characterization of the bio-optical anomaly and diurnal variability of particulate matter, as seen from scattering and backscattering coefficients, in ultra-oligotrophic eddies of the Mediterranean Sea

et al. 2011

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Abstract. The variability of inherent optical properties is investigated in the ultra-oligotrophic waters of the Mediterranean Sea sampled during the BOUM experiment performed during early summer 2008. Bio-optical relationships found for ultra-oligotrophic waters of the three anticyclonic gyres sampled significantly depart from the mean standard relationships provided for the global ocean, confirming the peculiar character of these Mediterranean waters. These optical anomalies are diversely related to the specific biological and environmental conditions occurring in the studied ecosystem. Specifically, the surface specific phytoplankton absorption coefficient exhibits values lower than those expected from the general relationships mainly in relation with a high contribution of relatively large sized phytoplankton. Conversely, the particulate backscattering coefficient, b bp , values are much higher than the mean standard values for a given chlorophyll-a concentration, TChl-a. This feature can presumably be related to the relevant influence of highly refractive submicrometer particles of Saharan origin in the surface layer of the water column. The present measurements Correspondence to: H. Loisel (hubert.loisel@univ-littoral.fr) also show that the Mediterranean Sea is greener than TChla alone indicates, as already stressed in previous studies. This color anomaly is partly explained by the estimated colored dissolved organic matter and submicrometer particles absorption coefficients, and to a greater extent by the high b bp /TChl-a values assuming that these particles backscatter light similarly in the green and blue parts of the visible spectrum. The diel variation of both the particulate matter attenuation and backscattering coefficients were also investigated specifically. Despite some differences in the timing and the magnitude of the daily oscillations found for these optical parameters, potential for the backscattering coefficient daily oscillation to be used, similarly to that for the attenuation coefficient, as a proxy for estimating carbon community production budget has been highlighted for the first time. This result is particularly relevant for present and future geostationary spatial ocean color missions.

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Section: Diel Cycle Insupporting

confidence: 50%

Characterization of the bio-optical anomaly and diurnal variability of particulate matter, as seen from scattering and backscattering coefficients, in ultra-oligotrophic eddies of the Mediterranean Sea

et al. 2011

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“…Observed mixed layer depths (MLD), based upon a 0.125 kg m -3 increase in sigma-t from ~5 m depth (Gardner et al, 1995), remained stable at 120 -140 m throughout this transect ( Figure 2B, Figure 3). However sampling was suspended for 36 hours during YD50-51, and is associated with a factor of two increase in 0-140 m integrated NO 3 -, suggesting rapid mixing followed by restratification.…”

Section: Brief Overview Of Biology and Physicsmentioning

confidence: 94%

Biogeochemical responses to late-winter storms in the Sargasso Sea, III—Estimates of export production using 234Th:238U disequilibria and sediment traps

Maiti

Benitez-Nelson

Lomas

et al. 2009

Deep Sea Research Part I: Oceanographic Research Papers

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“…All data presented as elemental ratios are in mol per mol units. Mixed layer depth was defined as a 0.125 kg m −3 difference in seawater density from the surface (Gardner et al, 1995). While mixed layer depths (MLDs) were always deepest during winter, the exact timing of the deepest mixing shifted between years.…”

Section: Data Processingmentioning

confidence: 99%

C : N : P stoichiometry at the Bermuda Atlantic Time-series Study station in the North Atlantic Ocean

et al. 2015

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Abstract. Nitrogen (N) and phosphorus (P) availability, in addition to other macro-and micronutrients, determine the strength of the ocean's carbon (C) uptake, and variation in the N : P ratio of inorganic nutrient pools is key to phytoplankton growth. A similarity between C : N : P ratios in the plankton biomass and deep-water nutrients was observed by Alfred C. Redfield around 80 years ago and suggested that biological processes in the surface ocean controlled deepocean chemistry. Recent studies have emphasized the role of inorganic N : P ratios in governing biogeochemical processes, particularly the C : N : P ratio in suspended particulate organic matter (POM), with somewhat less attention given to exported POM and dissolved organic matter (DOM). Herein, we extend the discussion on ecosystem C : N : P stoichiometry but also examine temporal variation in stoichiometric relationships. We have analyzed elemental stoichiometry in the suspended POM and total (POM + DOM) organic-matter (TOM) pools in the upper 100 m and in the exported POM and subeuphotic zone (100-500 m) inorganic nutrient pools from the monthly data collected at the Bermuda Atlantic Time-series Study (BATS) site located in the western part of the North Atlantic Ocean. C : N and N : P ratios in TOM were at least twice those in the POM, while C : P ratios were up to 5 times higher in TOM compared to those in the POM. Observed C : N ratios in suspended POM were approximately equal to the canonical Redfield ratio (C : N : P = 106 : 16 : 1), while N : P and C : P ratios in the same pool were more than twice the Redfield ratio. Average N : P ratios in the subsurface inorganic nutrient pool were ∼ 26 : 1, squarely between the suspended POM ratio and the Redfield ratio. We have further linked variation in elemental stoichiometry to that of phytoplankton cell abundance observed at the BATS site. Findings from this study suggest that elemental ratios vary with depth in the euphotic zone, mainly due to different growth rates of cyanobacterial cells. We have also examined the role of the Arctic Oscillation on temporal patterns in C : N : P stoichiometry. This study strengthens our understanding of the variability in elemental stoichiometry in different organic-matter pools and should improve biogeochemical models by constraining the range of non-Redfield stoichiometry and the net relative flow of elements between pools.

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The oceanic mixed-layer pump

Cited by 151 publications

References 36 publications

Characterization of the bio-optical anomaly and diurnal variability of particulate matter, as seen from scattering and backscattering coefficients, in ultra-oligotrophic eddies of the Mediterranean Sea

Characterization of the bio-optical anomaly and diurnal variability of particulate matter, as seen from scattering and backscattering coefficients, in ultra-oligotrophic eddies of the Mediterranean Sea

Biogeochemical responses to late-winter storms in the Sargasso Sea, III—Estimates of export production using 234Th:238U disequilibria and sediment traps

C : N : P stoichiometry at the Bermuda Atlantic Time-series Study station in the North Atlantic Ocean

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