Particulate Organic Carbon Deconstructed: Molecular and Chemical Composition of Particulate Organic Carbon in the Ocean

Kharbush, Jenan J.; Close, Hilary G.; Mooy, Benjamin A. S. Van; Arnosti, Carol; Smittenberg, Rienk H.; Moigne, Frédéric A.C. Le; Mollenhauer, Gesine; Scholz‐Böttcher, Barbara M.; Obreht, Igor; Koch, Boris P.; Becker, Kevin W.; Iversen, Morten Hvitfeldt; Mohr, Wiebke

doi:10.3389/fmars.2020.00518

Cited by 92 publications

(62 citation statements)

References 138 publications

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“…Based on the analysis of δ 13 C-POC in 51 profiles in the global ocean, Close and Henderson (2020) reported that δ 13 C-POC had the abovementioned vertical distribution rule in most regions. Microorganisms first decompose the heavier δ 13 C components in the POC, such as amino acids and carbohydrates, resulting in lighter δ13C components, and this fractionation process of δ13C-POC is one of the main reasons for the lighter δ13C-POC with the increase in water depth (Close and Henderson, 2020;Kharbush et al, 2020). These results indicate that δ 13 C-POC could be an important reference for the study of POC decomposition.…”

Section: The Production and Decomposition Of Pocmentioning

confidence: 88%

The OMZ and Its Influence on POC in the Tropical Western Pacific Ocean: Based on the Survey in March 2018

Song

et al. 2021

Front. Earth Sci.

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The hypoxia problem in the ocean is worsening, and the oxygen minimum zone (OMZ) continues to expand. The Tropical Western Pacific Ocean is one of the most sensitive areas in response to climate change and human activities, and the OMZ in this area has also expanded significantly. Based on a survey conducted in March 2018, the characteristics of OMZ in the Kocebu seamount area of the Tropical Western Pacific Ocean and its biogeochemical effects are discussed. The results showed that DO in the Kocebu seamount area first decreased and then increased, and the lowest value was 2.49 mg/L at a water depth of 750 m. Based on the oxycline and the threshold of 3.20 mg/L, OMZ in this area was located in the water column of 590–1,350 m. With the increase in water depth, the POC concentration decreased gradually and remained stable in the water column deeper than 1,000 m. The presence of OMZ reduced the decomposition rate of POC, causing more POC to sink into deeper waters. 38.77% of POC was decomposed in the water column of 150–300 m, whereas only 16.25% of POC was decomposed in the OMZ. In contrast to the vertical distribution of POC, δ13C-POC decreased rapidly in the water columns of 100–150 and 300–500 m, indicating the rapid decomposition of POC. This result suggests that POC and δ13C-POC should be combined in the evaluation of POC decomposition.

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Section: The Production and Decomposition Of Pocmentioning

confidence: 88%

The OMZ and Its Influence on POC in the Tropical Western Pacific Ocean: Based on the Survey in March 2018

Song

et al. 2021

Front. Earth Sci.

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“…Moreover, herbivores encounter rapidly changing food quality in company with changes in the diverse species, quantity, and biochemical characteristics of their prey ( Scott, 1980 ; Finkel et al, 2010 ). In addition, differential preservation of biochemical compounds in accordance with reactive changes of the altered biochemical composition of POM under ongoing climate changes could have effects on remineralization rates and sinking particles in the deep sea ( Ingalls et al, 2006 ; Kharbush et al, 2020 ; Lehmann et al, 2020 ). Therefore, additional research with multidiscipline approaches is required to evaluate the important food quality as a food source for higher trophic level organisms and understand complicated biochemical parameters associated with climate changes.…”

Section: Discussionmentioning

confidence: 99%

Different Biochemical Compositions of Particulate Organic Matter Driven by Major Phytoplankton Communities in the Northwestern Ross Sea

Kim

et al. 2021

Front. Microbiol.

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Marine particulate organic matter (POM) largely derived from phytoplankton is a primary food source for upper trophic consumers. Their biochemical compositions are important for heterotrophs. Especially, essential amino acids (EAAs) in phytoplankton are well known to have impacts on the survival and egg productions of herbivorous zooplankton. To estimate the nutritional quality of POM, the biochemical compositions [biomolecular and amino acid (AA) compositions] of POM were investigated in the northwestern Ross Sea during the late austral summer in 2018. Carbohydrates (CHO) accounted for the highest portion among different biomolecules [CHO, proteins (PRT), and lipids (LIP)] of POM. However, the higher contribution of PRT and lower contribution of CHO were observed in the southern section of our study area compared to those in the northern section. The spatial distribution of total hydrolyzable AAs in POM was considerably influenced by phytoplankton biomass, which indicates that the main source of particulate AA was generated by phytoplankton. Our results showed that the relative contribution of EAA to the total AAs was strongly associated with EAA index (EAAI) for determining protein quality. This result indicates that higher EAA contribution in POM suggests a better protein quality in consistency with high EAAI values. In this study, variations in the biochemical compositions in POM were principally determined by two different bloom-forming taxa (diatoms and Phaeocystis antarctica). The southern region dominated majorly by diatoms was positively correlated with PRT, EAA, and EAAI indicating a good protein quality, while P. antarctica-abundant northern region with higher CHO contribution was negatively correlated with good protein quality factors. Climate-driven environmental changes could alter not only the phytoplankton community but also the physiological conditions of phytoplankton. Our findings could provide a better understanding for future climate-induced changes in the biochemical compositions of phytoplankton and consequently their potential impacts on higher trophic levels.

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“…Rhone delta data (Table 2; rows B and C) are from the DI-CASE project (Rassmann et al, 2016). Data for the northern European margin sites Aarhus Bay, Arkona Basin, and the Skagerrak transect (Table 2; rows D, E, G, H, and I) are part of the Europe-funded project METROL (Aquilina et al, 2010;Dale et al, 2008a, b;Knab et al, 2008; (Henkel and Kulkarni, 2015), the Arabian Sea oxygen minimum zone (OMZ) transect (Table 2; rows J, K, and L) (Bohrmann and cruise participants, 2010a, b, c), Bering Sea (Table 2; row M) (Gersonde, 2009), and Argentine Basin (Table 2; row N) (Henkel et al, 2011) are presented in the PANGAEA database (see above). We use those site-specific datasets to inform our data-model analysis and to constrain OM reactivity and related benthic processes.…”

Section: Observational Datamentioning

confidence: 99%

New insights into large-scale trends of apparent organic matter reactivity in marine sediments and patterns of benthic carbon transformation

et al. 2021

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Abstract. Constraining the mechanisms controlling organic matter (OM) reactivity and, thus, degradation, preservation, and burial in marine sediments across spatial and temporal scales is key to understanding carbon cycling in the past, present, and future. However, we still lack a detailed quantitative understanding of what controls OM reactivity in marine sediments and, consequently, a general framework that would allow model parametrization in data-poor areas. To fill this gap, we quantify apparent OM reactivity (i.e. OM degradation rate constants) by extracting reactive continuum model (RCM) parameters (a and v, which define the shape and scale of OM reactivity profiles, respectively) from observed benthic organic carbon and sulfate dynamics across 14 contrasting depositional settings distributed over five distinct benthic provinces. We further complement the newly derived parameter set with a compilation of 37 previously published RCM a and v estimates to explore large-scale trends in OM reactivity. Our analysis shows that the large-scale variability in apparent OM reactivity is largely driven by differences in parameter a (10−3–107) with a high frequency of values in the range 100–104 years. In contrast, and in broad agreement with previous findings, inversely determined v values fall within a narrow range (0.1–0.2). Results also show that the variability in parameter a and, thus, in apparent OM reactivity is a function of the whole depositional environment, rather than traditionally proposed, single environmental controls (e.g. water depth, sedimentation rate, OM fluxes). Thus, we caution against the simplifying use of a single environmental control for predicting apparent OM reactivity beyond a specific local environmental context (i.e. well-defined geographic scale). Additionally, model results indicate that, while OM fluxes exert a dominant control on depth-integrated OM degradation rates across most depositional environments, apparent OM reactivity becomes a dominant control in depositional environments that receive exceptionally reactive OM. Furthermore, model results show that apparent OM reactivity exerts a key control on the relative significance of OM degradation pathways, the redox zonation of the sediment, and rates of anaerobic oxidation of methane. In summary, our large-scale assessment (i) further supports the notion of apparent OM reactivity as a dynamic ecosystem property, (ii) consolidates the distributions of RCM parameters, and (iii) provides quantitative constraints on how OM reactivity governs benthic biogeochemical cycling and exchange. Therefore, it provides important global constraints on the most plausible range of RCM parameters a and v and largely alleviates the difficulty of determining OM reactivity in RCM by constraining it to only one variable, i.e. the parameter a. It thus represents an important advance for model parameterization in data-poor areas.

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Particulate Organic Carbon Deconstructed: Molecular and Chemical Composition of Particulate Organic Carbon in the Ocean

Cited by 92 publications

References 138 publications

The OMZ and Its Influence on POC in the Tropical Western Pacific Ocean: Based on the Survey in March 2018

The OMZ and Its Influence on POC in the Tropical Western Pacific Ocean: Based on the Survey in March 2018

Different Biochemical Compositions of Particulate Organic Matter Driven by Major Phytoplankton Communities in the Northwestern Ross Sea

New insights into large-scale trends of apparent organic matter reactivity in marine sediments and patterns of benthic carbon transformation

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