Annual cycle of organic matter partitioning and its availability to bacteria across the Santa Barbara Channel continental shelf

Halewood, Elisa R.; Carlson, Craig A.; Brzezinski, Mark A.; Reed, Daniel C.; Goodman, Jo

doi:10.3354/ame01586

Cited by 27 publications

(35 citation statements)

References 74 publications

(96 reference statements)

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“…Other upwelling regions show a similar relationship between nutrient supply and TOC or DOC production, such as the equatorial Pacific Ocean (Peltzer & Hayward, ), Iberian Peninsula (Álvarez‐Salgado et al, ), Ross Sea (Carlson et al, ), eastern North Pacific Ocean off Oregon (Hill & Wheeler, ), East China Sea (Ogawa & Tanoue, ), Oyashio Current (Hasegawa et al, ), and SBC (Halewood et al, ; Wear et al, ). In the southern CCE, bottle incubation studies that have measured DOC and suspended POC production during phytoplankton grow out experiments have also confirmed the partitioning of new production into detrital reservoirs (Halewood et al, ; Wear et al, ).…”

Section: Discussionmentioning

confidence: 98%

“…This suspended POM can represent a significant fraction of the carbon and nitrogen accumulating in coastal environments following periods of upwelling (Hill & Wheeler, ; Walker & McCarthy, ). Dissolved organic matter (DOM) contributes the highest concentration of organic carbon to the water column in most oceanic environments (Halewood et al, ; Hill & Wheeler, ; Walker & McCarthy, ; Wear et al, ). Both DOM and suspended POM are treated here as separate and distinct from fast‐sinking particles, but both have been shown to participate in lateral export following subduction and advection (Abell et al, ; Carlson et al, ; Duarte et al, ; Letscher et al, , ; Omand et al, ; Siegel et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Nonsinking Organic Matter Production in the California Current

Stephens

Porrachia

Dovel

et al. 2018

Global Biogeochemical Cycles

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Productive eastern boundary upwelling systems such as the California Current Ecosystem (CCE) are important regions for supporting both local and remote food webs. Several studies have reported on the temporal and spatial variability of primary production and gravitational export in the CCE. However, few studies have quantified the partitioning of net primary and new production into other reservoirs of detrital organic matter. This study tested the hypothesis that nonsinking detrital reservoirs are an exportable reservoir of new production in the CCE with samples collected by the California Cooperative Oceanic Fisheries Investigation survey between 2008 and 2010. Water column gradients in nitrate (NO3−) and total organic carbon (TOC; which excludes sinking particulate organic carbon) were used to estimate potential rates of new production (PNew) and TOC production (PTOC), respectively. The PTOC:PNew varied between 0.16 and 0.56 and often increased with indicators of enhanced autotrophic production. At times, surface stratification was also correlated with elevated PTOC:PNew. In the most productive, inshore region, PTOC exceeded previously reported sinking export rates, which identified TOC as a quantitatively significant repository of exportable carbon in the CCE. However the sum of PTOC and sinking export for these productive regions was less than both PNew and oxygen‐based estimates of net community production. These results imply that nonsinking reservoirs alone are not sufficient to explain observed imbalances between production and export for the most productive CCE regions.

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Nonsinking Organic Matter Production in the California Current

Stephens

Porrachia

Dovel

et al. 2018

Global Biogeochemical Cycles

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“…This is the result of a fast and efficient recycling of biomass in this system. A significant fraction of the photosynthetic production is channeled through the dissolved organic matter (DOM) reservoir (Halewood et al, 2012; Stephens and Aluwihare, in review); and recycled by bacteria (Azam and Malfatti, 2007). The DOM reservoir comprises 600 Gt C, making it the largest reduced carbon (C) reservoir in the ocean and comparable in size to the atmospheric CO 2 reservoir.…”

Section: Introductionmentioning

confidence: 99%

High-Resolution Liquid Chromatography Tandem Mass Spectrometry Enables Large Scale Molecular Characterization of Dissolved Organic Matter

et al. 2017

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Dissolved organic matter (DOM) is arguably one of the most complex exometabolomes on earth, and is comprised of thousands of compounds, that together contribute more than 600 × 10 15 g carbon. This reservoir is primarily the product of interactions between the upper ocean's microbial food web, yet abiotic processes that occur over millennia have also modified many of its molecules. The compounds within this reservoir play important roles in determining the rate and extent of element exchange between inorganic reservoirs and the marine biosphere, while also mediating microbe-microbe interactions. As such, there has been a widespread effort to characterize DOM using high-resolution analytical methods including nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). To date, molecular information in DOM has been primarily obtained through calculated molecular formulas from exact mass. This approach has the advantage of being non-targeted, accessing the inherent complexity of DOM. Molecular structures are however still elusive and the most commonly used instruments are costly. More recently, tandem mass spectrometry has been employed to more precisely identify DOM components through comparison to library mass spectra. Here we describe a data acquisition and analysis workflow that expands the repertoire of high-resolution analytical approaches available to access the complexity of DOM molecules that are amenable to electrospray ionization (ESI) MS. We couple liquid chromatographic separation with tandem MS (LC-MS/MS) and a data analysis pipeline, that integrates peak extraction from extracted ion chromatograms (XIC), molecular formula calculation and molecular networking. This provides more precise structural characterization. Although only around 1% of detectable DOM compounds can be annotated through publicly available spectral libraries, community-wide participation in populating and annotating DOM datasets could rapidly increase the annotation rate and should be broadly encouraged. Our analysis also identifies shortcomings of the current Petras et al. LC-MS/MS Analysis of DOMdata analysis workflow that need to be addressed by the community in the future. This work will lay the foundation for an integrative, non-targeted molecular analysis of DOM which, together with next generation sequencing, meta-proteomics and physical data, will pave the way to a more comprehensive understanding of the role of DOM in structuring marine ecosystems.

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“…In more eutrophic areas, such as upwelling coastal habitats, the spatial and temporal heterogeneity of bulk DOC concentrations, reactive fractions, and microbial responses can be large and dynamic at both diurnal and seasonal scales ( Fig. 1) (10).…”

mentioning

confidence: 99%