Decomposing the Oxygen Signal in the Ocean Interior: Beyond Decomposing Organic Matter

Cassar, Nicolas; Nicholson, David P.; Khatiwala, S.; Cliff, Ellen

doi:10.1029/2021gl092621

Cited by 6 publications

(5 citation statements)

References 67 publications

(122 reference statements)

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“…Preformed and observed oxygen concentrations were then linearly interpolated in three dimensions from the OCIM2 grid back to the GLODAPv2 coordinates. This TOU product compares well with other recent independent TOU estimates (Carter et al., 2021; Cassar et al., 2021), see Figure 1; Figure S1 in Supporting Information S1.…”

Section: Methodssupporting

confidence: 88%

Respiration Patterns in the Dark Ocean

Sulpis

Trossman

Holzer

et al. 2023

Global Biogeochemical Cycles

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In the dark ocean, respiring organisms are the main sink for dissolved oxygen. The respiration rate in a given seawater volume can be quantified through dissolved oxygen drawdown or organic matter consumption as a function of time. Estimates of dissolved oxygen utilization rates (OUR) abound in the literature, but are typically obtained using proxies of questionable accuracy, often with low vertical resolution, and neglecting key regions such as the Southern and Indian oceans. Respiration rates based on particulate (POC) or dissolved (DOC) organic carbon are also sparsely observed and for DOC unavailable in many regions. Consequently, the relative contributions of POC or DOC as a respiration substrate in the dark ocean are unknown. Here we use recent datasets of true oxygen utilization, seawater age, and DOC to derive OUR and DOC consumption‐rate profiles in 10 oceanic regions. We demonstrate that although DOC and POC consumption rates are globally consistent with OUR, they underestimate OUR in the deep, suggesting strong oxygen utilization at the seafloor. In the abyss, we find a negative correlation of DOC consumption rate with seawater age, suggesting that DOC reactivity decreases along the deep branch of the conveyor circulation. Our results highlight that benthic organisms are sensitive to perturbations in the surface production of organic matter and to large‐scale circulation changes that affect its supply to the abyss.This article is protected by copyright. All rights reserved.

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Section: Methodssupporting

confidence: 88%

Respiration Patterns in the Dark Ocean

Sulpis

Trossman

Holzer

et al. 2023

Global Biogeochemical Cycles

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“…To evaluate the performance of our three numerical approaches, we compile field measurements of O 2 /Ar and O 2 from 14 cruises (Figure 1, Table S1 in Supporting Information S1): two cruises in the Southern Ocean, SO‐GasEx‐2008 (https://www.bco-dmo.org/dataset/4059; Hamme et al., 2012), and LTER‐2012 (https://zenodo.org/record/5786352; Eveleth et al., 2017), three cruises in the North Atlantic (Bermuda‐2017, Bermuda‐2016, and Bermuda‐2015, https://zenodo.org/record/5786352; Tang et al., 2019; Wang et al., 2018), six cruises in North Pacific, KM1906‐2016 (https://zenodo.org/record/4009653; Juranek et al., 2020), Oceanus‐2017, Line P‐2019‐001, Line P‐2018‐040 and La Perouse‐2017‐009 (https://doi.pangaea.de/10.1594/PANGAEA.933345; Izett et al., 2021; R. Izett & Tortell, 2020), California‐2016 (https://oceaninformatics.ucsd.edu/datazoo/catalogs/ccelter/datasets/290; Wang et al., 2020), and three Arctic cruises, OS191901‐2019 (https://arcticdata.io/catalog/view/doi%3A10.18739/A2HH6C69V), CCGS Amunden‐2019 (https://doi.pangaea.de/10.1594/PANGAEA.933345; Izett et al., 2021), and CCIN13242‐2018 (https://zenodo.org/record/6124142; Izett et al., 2021). The data near the ice‐covered regions from the LTER‐2012 cruise are not included because of difficulties in parameterizing the effects of ice dynamics on gas saturation (Cassar et al., 2021; Eveleth et al., 2014).…”

Section: Methodsmentioning

confidence: 99%

“…YmheU_PMK3I; . The data near the ice-covered regions from the LTER-2012 cruise are not included because of difficulties in parameterizing the effects of ice dynamics on gas saturation (Cassar et al, 2021;Eveleth et al, 2014).…”

Section: Underway Concurrent Measurements Of O 2 /Ar and O 2 For The ...mentioning

confidence: 99%

Can We Estimate Air‐Sea Flux of Biological O₂ From Total Dissolved Oxygen?

Huang

Eveleth

Nicholson

et al. 2022

Global Biogeochemical Cycles

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In this study, we compare mechanistic and empirical approaches to reconstruct the air‐sea flux of biological oxygen (FO2bio_as ${\mathrm{F}}_{{\left[{\mathrm{O}}_{2}\right]}_{{\text{bio}}^{\_\text{as}}}}$) by parameterizing the physical oxygen saturation anomaly (ΔO2[phy]) in order to separate the biological contribution from total oxygen. The first approach matches ΔO2[phy] to the monthly climatology of the argon saturation anomaly from a global ocean circulation model's output. The second approach derives ΔO2[phy] from an iterative mass balance model forced by satellite‐based physical drivers of ΔO2[phy] prior to the sampling day by assuming that air‐sea interactions are the dominant factors driving the surface ΔO2[phy]. The final approach leverages the machine‐learning technique of Genetic Programming (GP) to search for the functional relationship between ΔO2[phy] and biophysicochemical parameters. We compile simultaneous measurements of O2/Ar and O2 concentration from 14 cruises to train the GP algorithm and test the validity and applicability of our modeled ΔO2[phy] and FO2bio_as ${\mathrm{F}}_{{\left[{\mathrm{O}}_{2}\right]}_{{\text{bio}}^{\_\text{as}}}}$. Among the approaches, the GP approach, which incorporates ship‐based measurements and historical records of physical parameters from the reanalysis products, provides the most robust predictions (R2 = 0.74 for ΔO2[phy] and 0.72 for FO2bio_as ${\mathrm{F}}_{{\left[{\mathrm{O}}_{2}\right]}_{{\text{bio}}^{\_\text{as}}}}$; RMSE = 1.4% for ΔO2[phy] and 7.1 mmol O2 m−2 d−1 for FO2bio_as ${\mathrm{F}}_{{\left[{\mathrm{O}}_{2}\right]}_{{\text{bio}}^{\_\text{as}}}}$). We use the empirical formulation derived from GP approach to reconstruct regional, inter‐annual, and decadal variability of FO2bio_as ${\mathrm{F}}_{{\left[{\mathrm{O}}_{2}\right]}_{{\text{bio}}^{\_\text{as}}}}$ based on historical oxygen records. Overall, our study represents a first attempt at deriving FO2bio_as ${\mathrm{F}}_{{\left[{\mathrm{O}}_{2}\right]}_{{\text{bio}}^{\_\text{as}}}}$ from snapshot measurements of oxygen, thereby paving the way toward using historical O2 data and a rapidly growing number of O2 measurements on autonomous platforms for independent insight into the biological pump.

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“…On longer time scales, radiocarbon (Sarnthein et al., 2013; Skinner et al., 2017), the isotope pair 231 Pa and 230 Th (McManus et al., 2004; Yu et al., 1996) and neodymium isotopes (Bohm et al., 2015; Goldstein & Hemming, 2003; Rutberg et al., 2000), are widely used as proxies of past ocean circulation. Other tracers of physical and biogeochemical relevance include, ventilation tracers such as ideal age (England, 1995; Thiele & Sarmiento, 1990), preformed tracers (Ito & Follows, 2005; Ito et al., 2004; Khatiwala et al., 2019; Lauderdale et al., 2013; Williams & Follows, 2011) and noble gases (Cassar et al., 2021; Hamme et al., 2019; Nicholson et al., 2016).…”

Section: Introductionmentioning

confidence: 99%