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  • 1
    Online Resource
    Online Resource
    San Diego :Elsevier Science & Technology,
    Keywords: Seawater -- Organic compound content. ; Chemical oceanography. ; Biogeochemistry. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (712 pages)
    Edition: 2nd ed.
    ISBN: 9780124071537
    DDC: 551.46/6
    Language: English
    Note: Front Cover -- Biogeochemistry of Marine Dissolved Organic Matter -- Copyright -- Dedication -- Contents -- List of Contributors -- Foreword -- References -- Preface -- Chapter 1: Why Dissolved Organics Matter: DOC in Ancient Oceans and Past Climate Change -- I. Overview -- II. Marine Carbon Cycling -- A. A Tale of Three Ocean Carbon "Pumps" -- B. A Fourth Appears-The Microbial Carbon Pump -- III. Interpreting the Geological Past -- A. Carbon Isotopes as Proxies for Past Global Carbon Cycle Changes -- B. Reconstructing Past Steady-State Modes of Global Carbon Cycling -- C. Interpreting Transient Carbon Cycle Perturbations -- D. Ocean DOC and Ancient Carbon Cycling: An Example from the Paleocene and Eocene -- E. Ocean DOC and Ancient Carbon Cycling: An Example from the Precambrian -- IV. Implications for Future Global Change? -- Acknowledgements -- References -- Chapter 2: Chemical Characterization and Cycling of Dissolved Organic Matter -- I. Introduction -- II. Isolation of DOM from Seawater -- A. Isolation of Hydrophobic DOM by Solid-Phase Extraction -- B. Isolation of High Molecular Weight DOM by Ultrafiltration -- C. Isolation of DOM by Reverse Osmosis/Electrically Assisted Dialysis -- III. Chemical Characterization of DOM -- A. Polysaccharides in DOM -- B. Proteins and Amino Acids in DOM -- C. Humic Substances in Solid-Phase Extractable DOM (SPE-DOM) -- 1. Characterization of SPE-DOM by High-Field NMR -- 2. Characterization of SPE-DOM by High-Resolution MS -- IV. Links Between DOM Composition and Cycling -- A. Composition and the Cycling of Labile DOM -- B. Composition and the Cycling of Semi-Labile DOM -- C. Composition and the Cycling of Refractory DOM -- V. Future Research -- Acknowledgments -- References -- Chapter 3: DOM Sources, Sinks, Reactivity, and Budgets -- I. Introduction -- II. DOM Production Processes. , A. Extracellular Phytoplankton Production -- 1. Extracellular Release Models -- a. Overflow Model -- b. Passive Diffusion Mode -- c. Model Comparison -- 2. Experimental and Field Observations -- a. Using Radioisotopic Tracers -- b. Microcosm, Mesocosm, and Field Observations -- c. ER Quality and Transparent Exopolymer Particles -- B. Grazer-Induced DOM Production -- 1. Herbivory -- a. Mesozooplankton -- b. Microzooplankton -- 2. Omnivory and Carnivory -- 3. Bacterivory -- 4. Biogeochemical Significance -- C. DOM Production via Cell Lysis -- 1. Viral Lysis and the Viral Shunt -- a. Biogeochemical Significance -- 2. Bacterial Lysis -- 3. Allelopathy -- D. Solubilization of Particles -- E. Prokaryote Production of DOM -- 1. Chemoautotrophy -- 2. Chemoheterotrophy -- III. DOM Removal Processes -- A. Biotic Consumption of DOM -- 1. Prokaryotes -- a. Bacterial Growth Efficiency -- b. Bacterial Carbon Demand -- c. Photoheterotrophy -- 2. Eukaryotes -- B. Abiotic Removal Processes -- 1. Phototransformation -- 2. Sorption of DOM onto Particles -- 3. Condensation of Marine Microgels -- 4. Hydrothermal Circulation -- IV. DOM Accumulation -- A. Abiotic Formation of Biologically Recalcitrant DOM -- B. Biotic Formation of Recalcitrant DOM -- 1. Microbial Carbon Pump -- a. Direct Source via the MCP -- b. Microbial Transformation -- c. Time Scales of DOM Persistence -- 2. Limitation of Microbial Growth and DOM Accumulation -- 3. Eukaryote Source of Recalcitrant DOM -- C. Neutral Molecules and Preservation -- D. Biogeochemical Implications of Organic Matter Partitioning into Recalcitrant DOM -- V. DOM Reactivity -- A. Biologically Labile DOM -- B. Biologically Semi-labile and Semi-refractory DOM -- 1. SLDOC -- 2. SRDOC -- C. Biologically Refractory and Ultra-refractory DOM Pools -- 1. URDOC -- 2. RDOC -- VI. The Priming Effect. , VII. Microbial Community Structure and DOM Utilization -- VIII. DOC in the Ocean Carbon Budget -- A. Autochthonous Sources -- 1. Epipelagic -- 2. Ocean Interior -- a. Deep Chemoautotrophy -- B. Allochthonous Sources -- IX. Summary -- Acknowledgments -- References -- Chapter 4: Dynamics of Dissolved Organic Nitrogen -- I. Introduction -- II. DON Concentrations in Aquatic Environments -- A. Methods to Measure DON Concentrations -- B. Global Distributions and Fate -- C. Cross System Comparison -- D. Seasonal Variations -- III. Composition of the DON Pool -- A. Chemical Composition-Characterizable DON -- 1. Urea -- 2. Amino Acids -- 3. Humic and Fulvic Substances -- 4. Other Organic Compounds -- B. Chemical Composition-Opening the Black Box of Uncharacterized DON -- 1. DON Isolation Methods -- 2. DON Characterization Methods -- 3. Chemical Characteristics of Marine DON -- C. Concentration and Composition of the DON Pool: Research Priorities -- IV. Sources of DON to the Water Column -- A. Autochthonous Sources -- 1. Phytoplankton -- 2. N 2 Fixers -- 3. Bacteria -- 4. Micro- and Macrozooplankton -- 5. Viruses -- B. Allochthonous Sources -- 1. Rivers -- 2. Groundwater -- 3. Atmospheric Deposition -- C. Methods to Estimate Rates of Autochthonous DON Release -- D. Literature Values of DON Release Rates in Aquatic Environments -- 1. Bulk DON -- 2. Urea -- 3. Amino Acids and Other Organics -- E. Sources of DON: Research Priorities -- V. Sinks for DON -- A. DON Bioavailability -- B. Methods to Estimate Rates of DON Uptake -- 1. Measuring Uptake Rates -- 2. Determining Which Organisms Contribute to Uptake -- 3. Flow Cytometric Sorting -- 4. Molecular Approaches -- 5. Stable Isotope Probing -- C. Mechanisms that Contribute to DON Bioavailability -- 1. Enzymatic Decomposition -- 2. Pinocytosis -- 3. Photochemistry -- 4. Salinity-mediated Uptake. , D. Literature Values of DON Uptake in Aquatic Environments -- 1. Bulk DON -- 2. Urea -- 3. Amino Acids -- 4. Humic Substances -- 5. Other Organic Compounds -- E. Sinks for DON: Research Priorities -- VI. Summary -- A. DON Concentrations in Aquatic Environments -- B. Composition of the DON Pool -- C. Sources of DON to the Water Column -- D. Sinks for DON -- Acknowledgments -- References -- Chapter 5: Dynamics of Dissolved Organic Phosphorus -- I. Introduction -- II. Terms, Definitions, and Concentration Units -- III. The Early Years of Pelagic Marine P-Cycle Research (1884-1955) -- IV. The Pelagic Marine P-Cycle: Key Pools and Processes -- V. Sampling, Incubation, Storage, and Analytical Considerations -- A. Sampling -- B. Sample Processing, Preservation, and Storage -- C. Detection of P i and P-Containing Compounds in Seawater -- 1. Analysis of Pi -- 2. Analysis of TDP -- D. Analytical Interferences in SRP and TDP Estimation -- E. Use of Isotopic Tracers in P-cycle Research -- VI. DOP in the Sea: Variations in Space -- A. Regional and Depth Variations in DOP -- B. DOP Concentrations in the Deep Sea -- C. Stoichiometry of Dissolved and Particulate Matter Pools -- VII. DOP in the Sea: Variations in Time -- A. English Channel -- B. North Pacific Subtropical Gyre -- C. Eastern Mediterranean Sea -- VIII. DOP Pool Characterization -- A. Molecular Weight Characterization of the DOP Pool -- B. DOP Pool Characterization by Enzymatic Reactivity -- C. DOP Pool Characterization by 31 P-NMR -- D. DOP Pool Characterization by Partial Photochemical Oxidation -- E. Direct Measurement of DOP Compounds -- 1. Nucleic Acids -- 2. ATP and Related Nucleotides -- 3. Cyclic AMP -- 4. Lipids -- 5. Vitamins -- 6. Inorganic Poly-Pi and Pyro-Pi -- F. Biologically Available P -- G. DOP: The "Majority" View -- IX. DOP Production, Utilization, and Remineralization. , A. DOP Production and Remineralization -- B. Direct Utilization of DOP -- C. The Methylphosphonate "Cycle" -- D. Enzymes as P-cycle Facilitators -- E. Taxon-specific DOP Uptake -- F. DOP Interactions with Light and Suspended Minerals -- X. Conclusions and Prospectus -- Acknowledgments -- References -- Chapter 6: The Carbon Isotopic Composition of Marine DOC -- I. Introduction -- II. Carbon Isotope Geochemistry Primer -- A. Carbon-13 and Stable Isotope Systematics -- B. Carbon-14 -- III. DOC Isotope Ratio Methods -- IV. Isotopic Composition of Bulk Marine DOC -- A. The First Measurements -- B. The First δ 13 C and Δ 14 C Depth Profiles -- C. New Depth Profiles and Spatiotemporal Variability -- D. Mass Balance Constraints on Bulk Δ 14 C Values -- V. Isotopic Composition of DOM Constituents -- A. Characterization by Size Fractions -- B. Characterization by Compounds and Compound Classes -- VI. Summary and Conclusions -- Acknowledgments -- References -- Chapter 7: Reasons Behind the Long-Term Stability of Dissolved Organic Matter -- I. Introduction: The Paradox of DOM Persistence -- II. The Environment Hypothesis -- III. The Intrinsic Stability Hypothesis -- IV. The Molecular Diversity Hypothesis -- V. Concluding Remarks -- Acknowledgments -- References -- Chapter 8: Marine Photochemistry of Organic Matter: Processes and Impacts -- Introduction -- Impact of Photochemistry on Elemental Cycles -- Carbon -- Coupled Photochemical-Microbial DOC Degradation: Impact on Marine Food Web Dynamics -- Photochemical DIC Formation and Oxygen Consumption -- DIC Photoproduction -- DIC Photoproduction and Photochemical Oxygen Consumption, and Mechanisms of DIC Photoformation -- Carbon Monoxide Photoproduction and Transfer to the Atmosphere -- Sulfur -- Dimethylsulphoniopropionate -- Dimethylsulfide -- Dimethylsulfoxide -- Carbonyl Sulfide -- Minor Sulfur Species. , Nitrogen and Phosphorus.
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  • 2
    Online Resource
    Online Resource
    San Diego :Elsevier Science & Technology,
    Keywords: Seawater -- Organic compound content. ; Chemical oceanography. ; Biogeochemistry. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (807 pages)
    Edition: 1st ed.
    ISBN: 9780080500119
    DDC: 551.46/6
    Language: English
    Note: Front Cover -- Biogeochemistry of Marine Dissolved Organic Matter -- Copyright Page -- Contents -- Contributors -- Foreword -- Preface -- Chapter 1. Why Dissolved Organics Matter? -- I. Introduction -- II. DOM Research Pre-1970 -- III. DOM Research in the 1970s -- IV. DOM Research in the 1980s -- V. "New" DON and DOC -- VI. Why Dissolved Organics Matter -- VII. What did we Learn? -- References -- Chapter 2. Analytical Methods for Total DOM Pools -- I. Introduction -- II. Dissolved Organic Carbon Analysis -- III. Dissolved Organic Nitrogen Analysis -- IV. Dissolved Organic Phosphorus Analysis -- V. Multielemental Methods -- VI. The Limits of Elemental Analyses -- VII. The Need for Continual use of Reference Materials -- References -- Chapter 3. Chemical Composition and Reactivity -- I. Introduction -- II. Distribution and Chemical Characteristics of Bulk Marine DOM -- III. Major Topics of Ongoing and Future Research About the Cycling of DOM -- References -- Chapter 4. Production and Removal Processes -- I. Introduction -- II. DOM Production Processes -- III. DOM Removal Processes -- IV. DOM Lability -- V. DOM Accumulation -- VI. Summary -- References -- Chapter 5. Dynamics of DON -- I. Introduction -- II. Concentration and Composition of the DON Pool -- III. Sources of DON -- IV. Sinks for DON -- V. DON Turnover Times -- VI. Summary -- References -- Chapter 6. Dynamics of DOP -- I. Introduction -- II. Terms, Definitions, and Concentration Units -- III. The Early Years of Pelagic Marine P-Cycle Research (1884-1955) -- IV. The Pelagic Marine P-Cycle: Key Pools and Processes -- V. Sampling, Incubation, Storage, and Analytical Considerations -- VI. DOP in the Sea: Variations in Space -- VII. DOP in the Sea: Variations in Time -- VIII. DOP Pool Characterization -- IX. DOP Production, Utilization, and Remineralization -- X. Conclusions and Prospectus. , References -- Chapter 7. Marine Colloids and Trace Metals -- I. Introduction -- II. Definition of Marine Colloids -- III. Analytical Methods -- IV. Metal Content of Marine Colloidal Matter -- V. The Chemical Form of Colloidal Metals -- VI. Particulate-Based Estimates of Colloidal Metal Concentrations -- VII. Sources of Metal-Complexing Colloidal Ligands -- VIII. Measurement of Colloid Reaction Rates -- IX. The Biological Availability of Colloidal Bioactive Metals -- X. Summary -- References -- Chapter 8. Carbon Isotopic Composition of DOM -- I. Introduction -- II. Conventions and Definitions for Expressing Isotopic Contents of DOC -- III. Methods for Extracting DOC from Seawater for Isotopic Analysis -- IV. Measurements and Distributions of δ13C and Δ14C in Marine DOC -- V. Applications of δ13C and (Δ)14C in Marine DOC Cycling Studies -- VI. Summary and Future Challenges -- References -- Chapter 9. Photochemistry and the Cycling of Carbon, Sulfur, Nitrogen and Phosphorus -- I. Introduction -- II. Photochemical Transformation of Riverine and Marsh-Derived DOM Inputs to the Sea -- III. Impact of Photochemistry on Elemental Cycles -- IV. Unresolved Questions and Future Research -- References -- Appendix 1 -- Appendix 2 -- Appendix 3 -- Appendix 4 -- Chapter 10. Chromophoric DOM in the Coastal Environment -- I. Introduction -- II. Optical Properties -- III. Distribution -- IV. Sources and Sinks -- V. Summary and Future Areas of Research -- References -- Chapter 11. Chromophoric DOM in the Open Ocean -- I. Introduction -- II. Characterization of CDOM -- III. Observed CDOM Dynamics -- IV. Global CDOM Distribution Patterns -- V. Relationship Between DOM and CDOM in the Open Ocean -- VI. Implications for Photochemistry and Photobiology -- VII. Needs for Future Advances -- References -- Chapter 12. DOM in the Coastal Zone -- I. Introduction. , II. River Inputs -- III. Estuarine Processes -- IV. Accumulation of DOM in the Coastal Zone and Export Processes -- V. Conclusions -- References -- Chapter 13. Sediment Pore Waters -- I. Introduction -- II. Dissolved Organic Carbon in Sediment Pore Waters -- III. Dissolved Organic Nitrogen (DON) -- IV. DOM Compositional Data -- V. The Role of Benthic DOM Fluxes in the Ocean Carbon and Nitrogen Cycles -- VI. The Role of Pore-Water DOM in Sediment Carbon Preservation -- VII. Conclusions and Suggestions for Future Research -- Appendix: A Description of the DOM Advection/Diffusion/ Reaction Model -- References -- Chapter 14. DOC in the Arctic Ocean -- I. Introduction -- II. Sources of DOC to the Arctic Ocean -- III. Composition and Distribution of DOC within the Arctic Ocean -- IV. Summary of Sources and Sinks -- References -- Chapter 15. DOC in the Global Ocean Carbon Cycle -- I. Introduction -- II. Distribution of DOC -- III. Net Community Production of DOC -- IV. Contribution of DOC to the Biological Pump -- V. Research Priorities -- VI. Summary -- References -- Chapter 16. Modeling DOM Biogeochemistry -- I. Introduction -- II. Ecosystem Modeling Studies -- III. Modeling the Role of DOM in Ocean Biogeochemistry -- IV. Discussion and Conclusions -- References -- Index -- Color Plate Section.
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  • 3
    Book
    Book
    Amsterdam [u.a.] : Academic Press
    Keywords: Seawater Organic compound content ; Chemical oceanography ; Biogeochemistry ; Meerwasser ; Organische Verbindungen ; Biogeochemie
    Type of Medium: Book
    Pages: XXII, 774 S , Ill., graph. Darst., Kt
    ISBN: 0123238412
    DDC: 551.4601
    RVK:
    Language: English
    Note: Literaturangaben
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  • 4
    Book
    Book
    Amsterdam : Elsevier, Academic Press
    Keywords: Seawater Organic compound content ; Chemical oceanography ; Biogeochemistry ; Meer ; Organische Verbindungen ; Biogeochemie ; Meerwasser ; Meereschemie ; Gelöster organischer Stoff ; Meer ; Organische Verbindungen ; Biogeochemie ; Meerwasser ; Meereschemie ; Gelöster organischer Stoff
    Description / Table of Contents: "Marine dissolved organic matter (DOM) is a complex mixture of molecules found throughout the world's oceans. It plays a key role in the export, distribution, and sequestration of carbon in the oceanic water column, posited to be a source of atmospheric climate regulation. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, focuses on the chemical constituents of DOM and its biogeochemical, biological, and ecological significance in the global ocean, and provides a single, unique source for the references, information, and informed judgments of the community of marine biogeochemists. Presented by some of the world's leading scientists, this revised edition reports on the major advances in this area and includes new chapters covering the role of DOM in ancient ocean carbon cycles, the long term stability of marine DOM, the biophysical dynamics of DOM, fluvial DOM qualities and fate, and the Mediterranean Sea. Biogeochemistry of Marine Dissolved Organic Matter, Second Edition, is an extremely useful resource that helps people interested in the largest pool of active carbon on the planet (DOC) get a firm grounding on the general paradigms and many of the relevant references on this topic"--
    Type of Medium: Book
    Pages: XVIII, 693 S. , Ill., graph. Darst., Kt.
    Edition: 2. ed.
    ISBN: 9780124059405
    DDC: 551.4601
    Language: English
    Note: Literaturangaben
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 386 (1997), S. 59-61 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Data for this analysis were taken from published reports9"11. Concentrations of total carbon dioxide (referred to as dissolved inorganic carbon, DIC), total organic carbon (TOC), nitrate plus nitrite (referred to as total inorganic nitrogen, TIN), and total organic nitrogen (TON) were determined as ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillan Magazines Ltd.
    Nature 395 (1998), S. 263-266 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] There is as much carbon in dissolved organic material in the oceans as there is CO2 in the atmosphere, but the role of dissolved organic carbon (DOC) in the global carbon cycle is poorly understood. DOC in the deep ocean has long been considered to be uniformly distributed, and hence ...
    Type of Medium: Electronic Resource
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  • 7
    Publication Date: 2023-02-08
    Description: A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river‐influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high‐resolution pan‐Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25‐50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle‐reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the open ocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 ± 0.4 Sv (106 m3 s‐1). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologic cycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean.
    Type: Article , PeerReviewed
    Format: text
    Format: text
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  • 8
    Publication Date: 2024-02-07
    Description: This study traces dissolved organic matter (DOM) in different water masses of the Arctic Ocean and its effect on the distributions of trace elements (TEs; Fe, Cu, Mn, Ni, Zn, Cd) using fluorescent properties of DOM and the terrigenous biomarker lignin. The Nansen, Amundsen, and Makarov Basins were characterized by the influence of Atlantic water and the fluvial discharge of the Siberian rivers with high concentrations of terrigenous DOM (tDOM). The Canada Basin and the Chukchi Sea were characterized by Pacific water, modified through contact with productive shelf sediments with elevated levels of marine DOM. Within the surface layer of the Beaufort Gyre, meteoric water (river water and precipitation) was characterized by low concentrations of lignin and terrigenous DOM fluorescence proxies as DOM is removed during freezing. High-resolution in situ fluorescence profiles revealed that DOM distribution closely followed isopycnals, indicating the strong influence of sea-ice formation and melt, which was also reflected in strong correlations between DOM fluorescence and brine contributions. The relationship of DOM and hydrography to TEs showed that terrigenous and marine DOM were likely carriers of dissolved Fe, Ni, Cu from the Eurasian shelves into the central Arctic Ocean. Chukchi shelf sediments were important sources of dCd, dZn, and dNi, as well as marine ligands that bind and carry these TEs offshore within the upper halocline (UHC) in the Canada Basin. Our data suggest that tDOM components represent stronger ligands relative to marine DOM components, potentially facilitating the long-range transport of TE to the North Atlantic. Key Points Dissolved Organic Matter (DOM) distribution in the Arctic Ocean is largely controlled by sea ice formation and melt processes DOM distribution in the Arctic Ocean reveals its potential as a tracer for halocline formation and freshwater source assignments Terrigenous and marine DOM are carriers of trace elements from shelves to the open Arctic Ocean, but terrigenous DOM represent stronger ligands
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Format: text
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  • 9
    Publication Date: 2020-07-09
    Description: Abstract A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river-influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high-resolution pan-Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25�50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle-reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the open ocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 ± 0.4 Sv (106 m3 s�1). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologic cycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 10
    Publication Date: 2021-06-29
    Description: The ocean contains a large reservoir of dissolved organic matter (DOM) that persists for millennia. Both the very dilute concentrations of individual DOM molecules and intrinsic recalcitrance to microbial decay imparted by molecular structure are suggested mechanisms for this long residence time. Here, we report an experiment comparing the responses of surface and deep prokaryotes to DOM isolated and enriched by solid‐phase extraction from surface and deep waters of the subtropical North Atlantic Ocean. Extracts from both depths were qualitatively characterized as biologically recalcitrant given their similarly high C : N ratios of 26. Surface prokaryotes measurably drew down extracted dissolved organic carbon (DOC) concentrations, but the drawdown was only 4% of the initial enriched DOC concentration regardless of enrichment level or depth. Deep microbes, in contrast, did not cause observable changes in DOC concentrations. Surface and deep prokaryotes had similar temperature‐normalized growth responses to extracts from each depth. Biological indicators (e.g., kinetics) suggest that prokaryotes were less efficient at catalyzing surface than deep DOM (catalytic efficiencies of 0.003–0.005 vs. 0.02–0.03 h−1, respectively). These values indicate qualitative differences in extracted DOM from the two depths, perhaps suggesting a variable nature of the refractory DOC depending on depth. Moreover, only a small portion of the extracted DOM was biologically utilizable, regardless of concentration factor or depth, and essentially only a small fraction of it was incorporated into biomass. Microbial selection against substrates that meet modest energy but no growth demands may be a factor contributing to the long‐term stability of marine DOM.
    Keywords: 577.7 ; North Atlantic ; dissolved organic matter (DOM) ; microbial utilization
    Type: article
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