Advances in Marine Dissolved Organic Matter Dynamics

A special issue of Journal of Marine Science and Engineering (ISSN 2077-1312). This special issue belongs to the section "Chemical Oceanography".

Deadline for manuscript submissions: closed (30 September 2020) | Viewed by 14319

Special Issue Editors


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Guest Editor
Biophysics Institute, National Research Council (CNR), Pisa, Italy
Interests: dissolved organic matter (DOM) dynamics in both coastal areas and open sea waters, with particular regard to the role of DOM in the global carbon cycle; ocean–atmosphere interactions; DOM production and removal processes; DOM biological lability

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Co-Guest Editor
Institute of Marine Sciences, National Research Council (CNR), Rome, Italy
Interests: marine optics; remote sensing of ocean colour; ocean and ecosystem health; biodiversity; marine biogeochemistry; bio-optical algorithm development and evaluation; autonomous in situ observations
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Special Issue Information

Dear Colleagues,

Marine dissolved organic matter (DOM) is one of the largest reservoirs of carbon on the planet and represents the main source of energy for heterotrophic prokaryotes. Containing as much carbon as the atmosphere and having a great ecological significance, DOM plays a key role in regulating air–sea CO2 exchanges and oceanic carbon sequestration that, ultimately, controls the Earth’s climate.

This Special Issue aims at publishing the most exciting research with respect to in-field, laboratory, biogeochemical modeling, and space-based studies that can help to understand where we are and how we go further in the knowledge of marine DOM. Multiplatform observations and studies on DOM–microbe interactions are welcomed. Investigations both at the global as well as at the regional scale are encouraged.

Dr. Chiara Santinelli
Dr. Emanuele Organelli
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Marine Science and Engineering is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Dissolved organic matter
  • Chromophoric DOM (CDOM)
  • DOM–microbe interactions
  • CDOM and phytoplankton
  • Ocean observations
  • Biogeochemical modelling
  • Carbon cycle
  • Phosphorous cycle
  • Nitrogen cycle

Published Papers (6 papers)

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Research

22 pages, 4471 KiB  
Article
In-Situ Variability of DOM in Relation with Biogeochemical and Physical Parameters in December 2017 in Laucala Bay (Fiji Islands) after a Strong Rain Event
by Timoci Koliyavu, Chloe Martias, Awnesh Singh, Stéphane Mounier, Philippe Gérard and Cecile Dupouy
J. Mar. Sci. Eng. 2021, 9(3), 241; https://doi.org/10.3390/jmse9030241 - 24 Feb 2021
Cited by 2 | Viewed by 2379
Abstract
Heavy rain events alter the biogeochemical outflows, affects water quality and ecosystem health within the coastal waters of small Pacific Islands. We characterized snapshots of the optical fingerprints of dissolved organic matter (DOM) sources together with the select nutrients, biogeochemical and physical variables [...] Read more.
Heavy rain events alter the biogeochemical outflows, affects water quality and ecosystem health within the coastal waters of small Pacific Islands. We characterized snapshots of the optical fingerprints of dissolved organic matter (DOM) sources together with the select nutrients, biogeochemical and physical variables for 10 stations in December 2017 in Laucala Bay, Fiji Islands. DOM absorption coefficients and fluorescence components were determined via spectrofluorometry and Parallel Factor Analysis identifying four components: Type M, two terrestrial (humic, fulvic) components, and a protein component linked to marine biological activity. Associations of DOM together with climate variables and the other tested variables were determined via principal component, hierarchical cluster, and cross-correlation (Pearson) analysis. All component s (together with most tested variables) displayed higher values (plumes) at the southwest coast consistent with surface currents outflow during the wet season. Type M component associated with two allochthonous fluorescent components signaling anthropogenic forcings via riverine outflows. Terrigenous inputs association with autochthonous chromophoric dissolved organic matter (CDOM) is indicative of tidal mixing, dilution, and bottom resuspension processes. Positive correlations of dissolved organic carbon (DOC) with nutrients (NOx, PO4) elucidates DOM being utilized as energy sources. The positive correlation of DON with nutrients (NOx, PO4, Si(OH)4) reflects the role of DON as a nutrient source consistent with chlorophyll plume formation. Full article
(This article belongs to the Special Issue Advances in Marine Dissolved Organic Matter Dynamics)
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18 pages, 6360 KiB  
Article
CDOM Spatiotemporal Variability in the Mediterranean Sea: A Modelling Study
by Paolo Lazzari, Eva Álvarez, Elena Terzić, Gianpiero Cossarini, Ilya Chernov, Fabrizio D’Ortenzio and Emanuele Organelli
J. Mar. Sci. Eng. 2021, 9(2), 176; https://doi.org/10.3390/jmse9020176 - 09 Feb 2021
Cited by 6 | Viewed by 2166
Abstract
This study investigates the spatial and temporal variability of chromophoric-dissolved organic matter (CDOM) in the Mediterranean Sea. The analysis is carried out using a state-of-the-art 3D biogeochemical model. The model describes the plankton dynamics, the cycles of the most important limiting nutrients, and [...] Read more.
This study investigates the spatial and temporal variability of chromophoric-dissolved organic matter (CDOM) in the Mediterranean Sea. The analysis is carried out using a state-of-the-art 3D biogeochemical model. The model describes the plankton dynamics, the cycles of the most important limiting nutrients, and the particulate and dissolved pools of carbon. The source of CDOM is directly correlated to the dynamics of dissolved organic carbon (DOC) by a fixed production quota. Then CDOM degrades by photobleaching and remineralization. The main innovation of the system is the inclusion of a bio-optical radiative transfer model that computes surface upwelling irradiance, and therefore simulates remotely sensed reflectance (Rrs). Simulation results of three model configurations are evaluated using satellite Rrs, particularly at 412 nm, 443 nm, and 490 nm. All simulations show a winter minimum in Rrs for the considered bands. However, different parameterizations of DOC-release induce a different accumulation of CDOM, especially in the eastern Mediterranean, and a different Rrs signature: a more active microbial loop during summer implies a decrease of Rrs at 412 nm. We demonstrate how the usage of a bio-optical model allows us to corroborate hypotheses on CDOM-cycling based on blue–violet Rrs data, supporting the importance of this complementary data stream with respect to satellite-derived chlorophyll. Full article
(This article belongs to the Special Issue Advances in Marine Dissolved Organic Matter Dynamics)
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13 pages, 1471 KiB  
Article
DOM Biological Lability in an Estuarine System in Two Contrasting Periods
by Simona Retelletti Brogi, Raffaella Casotti, Benjamin Misson, Cecilia Balestra, Margherita Gonnelli, Stefano Vestri and Chiara Santinelli
J. Mar. Sci. Eng. 2021, 9(2), 172; https://doi.org/10.3390/jmse9020172 - 08 Feb 2021
Cited by 3 | Viewed by 1897
Abstract
Estuarine processes play a key role in determining the amount and quality of land-derived dissolved organic matter (DOM) reaching the oceans. Microbial-mediated reactions can affect the concentration, quality, and bioavailability of DOM within an estuary. In this study, we investigated biological DOM removal [...] Read more.
Estuarine processes play a key role in determining the amount and quality of land-derived dissolved organic matter (DOM) reaching the oceans. Microbial-mediated reactions can affect the concentration, quality, and bioavailability of DOM within an estuary. In this study, we investigated biological DOM removal in a small estuary and its variability in two contrasting seasons (spring and autumn) characterized by natural differences in the concentration and quality of the riverine DOM. Two incubation experiments were carried out using natural DOM and heterotrophic prokaryotes community collected at the estuary in March and September. Dissolved organic carbon (DOC) concentration, DOM fluorescence, and the heterotrophic prokaryotes abundance (HPA) showed marked differences between the two seasons. These parameters were followed through time for up to two months. Despite the marked differences in the initial conditions, the DOC removal rates were surprisingly similar in the two periods (16 µM DOC month−1 in March and 18 µM DOC month−1 in September), with the biggest removal in the first 48 h. The trend of fluorescent DOM (FDOM) during the incubation showed marked differences between the two periods. In March, the net removal of all the FDOM components was observed consistently with the decrease in DOC; whereas, in September, the net production of humic-like substances was observed. Full article
(This article belongs to the Special Issue Advances in Marine Dissolved Organic Matter Dynamics)
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18 pages, 3861 KiB  
Article
Posidonia oceanica as a Source of Chromophoric Dissolved Organic Matter for the Oligotrophic NW Mediterranean Coast
by Francesca Iuculano, Carlos M. Duarte, Jaime Otero, Xosé Antón Álvarez-Salgado and Susana Agustí
J. Mar. Sci. Eng. 2020, 8(11), 911; https://doi.org/10.3390/jmse8110911 - 12 Nov 2020
Cited by 2 | Viewed by 2122
Abstract
Posidonia oceanica is a well-recognized source of dissolved organic matter (DOM) derived from exudation and leaching of seagrass leaves, but little is known about its impact on the chromophoric fraction of DOM (CDOM). In this study, we monitored for two years the optical [...] Read more.
Posidonia oceanica is a well-recognized source of dissolved organic matter (DOM) derived from exudation and leaching of seagrass leaves, but little is known about its impact on the chromophoric fraction of DOM (CDOM). In this study, we monitored for two years the optical properties of CDOM in two contrasting sites in the Mallorca Coast (Balearic Islands). One site was a rocky shore free of seagrass meadows, and the second site was characterized by the accumulation of non-living seagrass material in the form of banquettes. On average, the integrated color over the 250–600 nm range was almost 6-fold higher in the beach compared with the rocky shore. Furthermore, the shapes of the CDOM spectra in the two sites were also different. A short incubation experiment suggested that the spectral differences were due to leaching from P. oceanica leaf decomposition. Furthermore, occasionally the spectra of P. oceanica was distorted by a marked absorption increase at wavelength < 265 nm, presumably related to the release of hydrogen sulfide (HS) associated with the anaerobic decomposition of seagrass leaves within the banquettes. Our results provide the first evidence that P. oceanica is a source of CDOM to the surrounding waters. Full article
(This article belongs to the Special Issue Advances in Marine Dissolved Organic Matter Dynamics)
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15 pages, 1915 KiB  
Article
Effect of UV and Visible Radiation on Optical Properties of Chromophoric Dissolved Organic Matter Released by Emiliania huxleyi
by Simona Retelletti Brogi, Bruno Charrière, Margherita Gonnelli, Frédéric Vaultier, Richard Sempéré, Stefano Vestri and Chiara Santinelli
J. Mar. Sci. Eng. 2020, 8(11), 888; https://doi.org/10.3390/jmse8110888 - 07 Nov 2020
Cited by 7 | Viewed by 2557
Abstract
Photodegradation is a natural process that strongly affects the chromophoric fraction of dissolved organic matter (DOM), especially in surface water of the oceans. In the euphotic zone, the concentration and quality of DOM are mostly dependent on primary production by phytoplankton. The effect [...] Read more.
Photodegradation is a natural process that strongly affects the chromophoric fraction of dissolved organic matter (DOM), especially in surface water of the oceans. In the euphotic zone, the concentration and quality of DOM are mostly dependent on primary production by phytoplankton. The effect of photodegradation on algal DOM has not been investigated as much as on terrestrial DOM. In this study, we explored the effect of different spectral regions (i.e., full sun spectrum, visible light, 295–800 nm, 305–800 nm, and 320–800 nm) on algal exudates by Emiliania huxleyi, a ubiquitous coccolithophore. The optical properties (absorption and fluorescence) of algal DOM were investigated before and after irradiation with the different spectral regions. The absorption and fluorescence spectra were compared before and after irradiation. The results showed an increase in the effect of photobleaching with increasing irradiation energy for all of the absorbance indices. Similarly, the protein-like fluorescence decreased at increasing irradiation energy. The humic-like fluorescence, which was the most affected, did not show a linear trend between photobleaching and irradiation energy, which suggested that irradiation mainly determined a change in these molecules’ quantum yield. Full article
(This article belongs to the Special Issue Advances in Marine Dissolved Organic Matter Dynamics)
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21 pages, 4037 KiB  
Article
Seasonal Dynamic of CDOM in a Shelf Site of the South-Eastern Ligurian Sea (Western Mediterranean)
by Luca Massi, Laura Frittitta, Chiara Melillo, Francesca Polonelli, Veronica Bianchi, Anna Maria De Biasi and Caterina Nuccio
J. Mar. Sci. Eng. 2020, 8(9), 703; https://doi.org/10.3390/jmse8090703 - 10 Sep 2020
Cited by 2 | Viewed by 2225
Abstract
Chromophoric dissolved organic matter (CDOM) is the fraction of the Dissolved Organic Carbon (DOC) mainly absorbing UV and blue radiation, influencing water optical properties, light availability for primary production, and water-leaving radiance. In open seas, phytoplankton is the main source of organic carbon [...] Read more.
Chromophoric dissolved organic matter (CDOM) is the fraction of the Dissolved Organic Carbon (DOC) mainly absorbing UV and blue radiation, influencing water optical properties, light availability for primary production, and water-leaving radiance. In open seas, phytoplankton is the main source of organic carbon and CDOM. Despite this, the direct or indirect phytoplankton role in CDOM production is not yet fully clarified. From studies about the relationship between CDOM and phytoplankton biomass as Chlorophyll a (Chl) in the epipelagic layer, positive correlations have been highlighted with regional differences and high levels of variability. Seven years of seasonal dynamic and vertical distribution of CDOM in the Ligurian Sea continental shelf waters have been analyzed in order to evidence the main environmental and/or biological factors determining CDOM dynamic, focusing on the CDOM/Chl relationship. CDOM optical properties (absorption at 440 nm, aCDOM (440), and spectral slope, S) allowed to distinguish different pools and to debate their origin. Four different pools were characterized and two of them were directly or indirectly related to phytoplankton biomass and taxonomic composition. Nevertheless, CDOM/Chl confirm a high level of variability These findings suggest some inputs to improve Mediterranean satellite estimates of Chl and CDOM, such as the seasonal differentiation of optical properties, especially S and CDOM/Chl relationships. Full article
(This article belongs to the Special Issue Advances in Marine Dissolved Organic Matter Dynamics)
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