Seasonal and inter‐annual variability of particulate organic matter in the global ocean

Loisel, Hubert; Nicolas, Jean-Marc; Deschamps, Pierre-Yves; Frouin, Robert

doi:10.1029/2002gl015948

Cited by 94 publications

(87 citation statements)

References 15 publications

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“…As such, particulate backscatter (b bp ) (Fig. S3b) was investigated as an alternate proxy for phytoplankton biomass (Loisel et al, 2002;Stramski et al, 1999), which similarly depicted the presence of a subsurface bloom in response to anticipated iron relief at depth.…”

Section: Discussionmentioning

confidence: 99%

Seasonal development of iron limitation in the sub-Antarctic zone

Ryan‐Keogh

Thomalla

Mtshali³

et al. 2018

Biogeosciences

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Abstract. The seasonal and sub-seasonal dynamics of iron availability within the sub-Antarctic zone (SAZ; ∼ 40-45 • S) play an important role in the distribution, biomass and productivity of the phytoplankton community. The variability in iron availability is due to an interplay between winter entrainment, diapycnal diffusion, storm-driven entrainment, atmospheric deposition, iron scavenging and iron recycling processes. Biological observations utilizing grow-out iron addition incubation experiments were performed at different stages of the seasonal cycle within the SAZ to determine whether iron availability at the time of sampling was sufficient to meet biological demands at different times of the growing season. Here we demonstrate that at the beginning of the growing season, there is sufficient iron to meet the demands of the phytoplankton community, but that as the growing season develops the mean iron concentrations in the mixed layer decrease and are insufficient to meet biological demand. Phytoplankton increase their photosynthetic efficiency and net growth rates following iron addition from midsummer to late summer, with no differences determined during early summer, suggestive of seasonal iron depletion and an insufficient resupply of iron to meet biological demand. The result of this is residual macronutrients at the end of the growing season and the prevalence of the high-nutrient low-chlorophyll (HNLC) condition. We conclude that despite the prolonged growing season characteristic of the SAZ, which can extend into late summer/early autumn, results nonetheless suggest that iron supply mechanisms are insufficient to maintain potential maximal growth and productivity throughout the season.

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Section: Discussionmentioning

confidence: 99%

Seasonal development of iron limitation in the sub-Antarctic zone

Ryan‐Keogh

Thomalla

Mtshali³

et al. 2018

Biogeosciences

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“…However, increasing evidence that aged DOC occurs at significant concentrations in the open ocean (Hansell et al, 2009), independent of phytoplankton dynamics, may require this assumption to be reevaluated. A range of products have been developed that give an indication of the surface distributions of pools of organic carbon constituents in the ocean, including colored (or chromophoric) dissolved organic material (CDOM; Siegel et al, 2002Siegel et al, , 2005Maritorena and Siegel, 2005;Morel and Gentili, 2009), DOC (Mannino et al, 2008), POC (Stramski et al, 1999;Loisel et al, 2002;Gardner et al, 2006;Sathyendranath et al, 2009;Stramska, 2009), phytoplankton size classes (PSC; Ciotti and Bricaud, 2006;Hirata et al, 2008aHirata et al, , 2011Brewin et al, 2010a, b;Uitz et al, 2010;Devred et al, 2011) and particle size distribution (PSD; Hirata et al, 2008b;Kostadinov et al, 2009Kostadinov et al, , 2010. Key uncertainties relate to the relationship between the absorption of light by CDOM and concentrations of DOC and to the contribution of very small particles (e.g., viruses) to particle backscattering signals used in the derivation of POC and PSD products (Stramski et al, 2008;Dall'Olmo et al, 2009).…”

Section: Monitoringmentioning

confidence: 99%

Mechanisms of microbial carbon sequestration in the ocean – future research directions

Jiao

Robinson²,

Azam³

et al. 2014

Biogeosciences

198

101

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Abstract. This paper reviews progress on understanding biological carbon sequestration in the ocean with special reference to the microbial formation and transformation of recalcitrant dissolved organic carbon (RDOC), the microbial carbon pump (MCP). We propose that RDOC is a concept with a wide continuum of recalcitrance. Most RDOC compounds maintain their levels of recalcitrance only in a specific environmental context (RDOC t ). The ocean RDOC pool also contains compounds that may be inaccessible to microbes due to their extremely low concentration (RDOC c ). This differentiation allows us to appreciate the linkage between microbial source and RDOC composition on a range of temporal and spatial scales.Analyses of biomarkers and isotopic records show intensive MCP processes in the Proterozoic oceans when the MCP could have played a significant role in regulating climate. Understanding the dynamics of the MCP in conjunction with the better constrained biological pump (BP) over geological timescales could help to predict future climate trends. Integration of the MCP and the BP will require new research approaches and opportunities. Major goals include understanding the interactions between particulate organic carbon (POC) and RDOC that contribute to sequestration efficiency, and the concurrent determination of the chemical composition of organic carbon, microbial community composition and enzymatic activity. Molecular biomarkers and isotopic tracers should be employed to link water column processes Published by Copernicus Publications on behalf of the European Geosciences Union. N. Jiao et al.: Mechanisms of microbial carbon sequestration in the oceanto sediment records, as well as to link present-day observations to paleo-evolution. Ecosystem models need to be developed based on empirical relationships derived from bioassay experiments and field investigations in order to predict the dynamics of carbon cycling along the stability continuum of POC and RDOC under potential global change scenarios. We propose that inorganic nutrient input to coastal waters may reduce the capacity for carbon sequestration as RDOC. The nutrient regime enabling maximum carbon storage from combined POC flux and RDOC formation should therefore be sought.

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“…The absorption coefficient by colored detrital matter, adg, provides information about detrital matter, which is mainly driven by colored dissolved organic matter in offshore waters. These three coefficients can be used to classify surface water masses [20], water composition assessment [21][22][23][24][25], oceanic primary production [16,26] and, in consequence, timing of the seasonal biological cycle of fishes (i.e., [27,28]) and potential fishing zones (i.e., [29][30][31]). Further, the derived products of ocean color imagery are a valuable source of data for ecosystem modeling, which provide forecasts of the development of plankton blooms, being useful warnings of harmful algal blooms and eutrophication risk (i.e., [31,32]).…”

Section: Introductionmentioning

confidence: 99%

Seasonal and Inter-Annual Analysis of Chlorophyll-a and Inherent Optical Properties from Satellite Observations in the Inner and Mid-Shelves of the South of Buenos Aires Province (Argentina)

et al. 2015

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Abstract:The aim of this study is to describe and understand the seasonal and inter-annual physical and biological dynamics of the inner and mid shelves of the Southwestern Buenos Aires Province (Argentina). We used chlorophyll-a (chl-a) concentrations and inherent optical properties (IOPs), derived from ocean color products between 2002 and 2010, as a proxy for the physical and biological parameters of interest. This study focuses on the absorption by phytoplankton, aph(443), particulate backscattering, bbp(443), and absorption due to dissolved and particulate detrital matter, adg (443), and chl-a derived from a multiband quasi-analytical algorithm (QAA). A regionalization based on the coefficient of variation and the Census X-11 method were applied to define regions and to analyze the inter-annual and seasonal variability of the ocean color parameters, with regards to climate OPEN ACCESSRemote Sens. 2015, 7 11822 variability. The coastal zone presents the highest values of chl-a with two maxima in winter and autumn, while the mid-shelf shows a strong spring chl-a maximum. After 2009, all parameters under study shifted their seasonality and their magnitude changed over the entire area. In the coastal zone, mean values of aph(443) and bbp(443) increased, while in the mid-shelf, chl-a and aph(443) decreased. The observed inter-annual and seasonal behavior of the parameters is tightly related to climate variability of the study area.

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Seasonal and inter‐annual variability of particulate organic matter in the global ocean

Cited by 94 publications

References 15 publications

Seasonal development of iron limitation in the sub-Antarctic zone

Seasonal development of iron limitation in the sub-Antarctic zone

Mechanisms of microbial carbon sequestration in the ocean – future research directions

Seasonal and Inter-Annual Analysis of Chlorophyll-a and Inherent Optical Properties from Satellite Observations in the Inner and Mid-Shelves of the South of Buenos Aires Province (Argentina)

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