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Muller FLL, Tankéré-Muller SPC, Tang CH. Terrigenous humic substances regulate the concentrations of dissolved Fe and Cu (but not Al, Mn, Ni or Zn) in the Gaoping River plume. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167374. [PMID: 37758148 DOI: 10.1016/j.scitotenv.2023.167374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/17/2023] [Accepted: 09/24/2023] [Indexed: 10/03/2023]
Abstract
The small mountainous rivers of Oceania discharge a large fraction of their dissolved and particulate load of materials within a very small percentage of the time. As a result, the yearly inputs and physicochemical forms of dissolved metals exported to the ocean by these rivers are poorly quantified. We investigated the wet-season distribution patterns of metals and fluorescent organic substances in the surface waters of the Gaoping River plume, SW Taiwan, under both moderate (Sep 2020) and strong flow conditions (Aug 2021). The mixing behaviour of both soluble (<5 kDa) and colloidal (>5 kDa) metals and fluorescent components was examined over the salinity range 3.0-32.2 in 2020 and 5.8-31.1 in 2021. We detected two humic-like and one protein-like fluorescent components, the same on both surveys. The humic-like components, C1 and C3, originated from the Gaoping River and correlated strongly with Cu and Fe, respectively. Component C3 showed a greater enrichment relative to C1 in the colloidal (C3/C1 > 0.8) than in the soluble phase (C3/C1 = 0.4). The protein-like component, C2, came from both terrestrial and marine sources and displayed a more complex mixing behaviour than the other two. One striking result was that the effective zero-salinity concentrations of Fe (∼300 nM) and Cu (∼23 nM) did not change significantly in response to a 10-fold increase in river discharge between Sep 2020 and Aug 2021. Similarly to Fe and Cu, the distribution patterns of Components C1 and C3 did not change significantly between the moderate and the strong plume, and C3 and C1 correlated strongly with Fe and Cu, respectively. We conclude that subtropical mountainous rivers can provide soil-derived humic substances which facilitate and regulate the delivery of Fe and Cu to the ocean, provided mountain forests are preserved.
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Affiliation(s)
- François L L Muller
- Department of Oceanography, National Sun Yat-sen University, 70 Lienhai Road, Kaohsiung 80424, Taiwan.
| | | | - Chuan-Ho Tang
- National Museum of Marine Biology and Aquarium, 2 Houwan Road, Checheng, Pingtung 94450, Taiwan
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Klaes B, Thiele-Bruhn S, Wörner G, Höschen C, Mueller CW, Marx P, Arz HW, Breuer S, Kilian R. Iron (hydr)oxide formation in Andosols under extreme climate conditions. Sci Rep 2023; 13:2818. [PMID: 36797309 PMCID: PMC9935883 DOI: 10.1038/s41598-023-29727-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 02/09/2023] [Indexed: 02/18/2023] Open
Abstract
Redox-driven biogeochemical cycling of iron plays an integral role in the complex process network of ecosystems, such as carbon cycling, the fate of nutrients and greenhouse gas emissions. We investigate Fe-(hydr)oxide (trans)formation pathways from rhyolitic tephra in acidic topsoils of South Patagonian Andosols to evaluate the ecological relevance of terrestrial iron cycling for this sensitive fjord ecosystem. Using bulk geochemical analyses combined with micrometer-scale-measurements on individual soil aggregates and tephra pumice, we document biotic and abiotic pathways of Fe released from the glassy tephra matrix and titanomagnetite phenocrysts. During successive redox cycles that are controlled by frequent hydrological perturbations under hyper-humid climate, (trans)formations of ferrihydrite-organic matter coprecipitates, maghemite and hematite are closely linked to tephra weathering and organic matter turnover. These Fe-(hydr)oxides nucleate after glass dissolution and complexation with organic ligands, through maghemitization or dissolution-(re)crystallization processes from metastable precursors. Ultimately, hematite represents the most thermodynamically stable Fe-(hydr)oxide formed under these conditions and physically accumulates at redox interfaces, whereas the ferrihydrite coprecipitates represent a so far underappreciated terrestrial source of bio-available iron for fjord bioproductivity. The insights into Fe-(hydr)oxide (trans)formation in Andosols have implications for a better understanding of biogeochemical cycling of iron in this unique Patagonian fjord ecosystem.
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Affiliation(s)
- Björn Klaes
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296, Trier, Germany. .,Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296, Trier, Germany.
| | - Sören Thiele-Bruhn
- grid.12391.380000 0001 2289 1527Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany
| | - Gerhard Wörner
- grid.7450.60000 0001 2364 4210Division of Geochemistry and Isotope Geology, GZG, Georg-August-University Göttingen, Goldschmidtstraße 1, 37077 Göttingen, Germany
| | - Carmen Höschen
- grid.6936.a0000000123222966Soil Science, Research Department Life Science Systems, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Straße 2, 85354 Freising-Weihenstephan, Germany
| | - Carsten W. Mueller
- grid.6936.a0000000123222966Soil Science, Research Department Life Science Systems, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Straße 2, 85354 Freising-Weihenstephan, Germany ,grid.5254.60000 0001 0674 042XDepartment for Geosciences and Environmental Management, University of Copenhagen, Øster Voldgade 10, 1350 København K, Denmark
| | - Philipp Marx
- grid.12391.380000 0001 2289 1527Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany
| | - Helge Wolfgang Arz
- grid.423940.80000 0001 2188 0463Marine Geology Section, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Seestraße 15, 18119 Rostock, Germany
| | - Sonja Breuer
- grid.15606.340000 0001 2155 4756Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover, Germany
| | - Rolf Kilian
- grid.12391.380000 0001 2289 1527Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany ,grid.442242.60000 0001 2287 1761University of Magallanes, Avenida Bulnes 01855, Punta Arenas, Chile
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Zhang Y, Liu C, Li Y, Song L, Yang J, Zuo R, Li J, Teng Y, Wang J. Spectroscopic Characteristics and Speciation Distribution of Fe(III) Binding to Molecular Weight-Dependent Standard Pahokee Peat Fulvic Acid. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19137838. [PMID: 35805509 PMCID: PMC9266197 DOI: 10.3390/ijerph19137838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 12/10/2022]
Abstract
Peat-derived organic matter, as powerful chelators, is of great significance for the transport of Fe to the ocean and the enhancement of dissolved Fe. However, the iron binding capacity of molecular weight (MW)-fractionated dissolved organic matter is variable, due to its structure and composition heterogeneity. In this work, we used the standard Pahokee Peat fulvic acid (PPFA) as an example, and investigated the spectroscopy properties and Fe(III) binding ability of PPFA and different molecular weight fractions by UV−Vis absorbance and fluorescence spectroscopy and the Donnan Membrane Technique (DMT). The results showed binding sites for Fe(III) at the 263 nm and >320 nm regions in differential absorbance spectra. Upon increasing the iron concentration to 18.00 μmol·L−1, the critical binding capacity was exceeded, which resulted in a decrease in absorbance. Fe(III) was found to prefer to bind to humic-like components, and ultraviolet humic-like fluorophores displayed stronger binding strength. High molecular weight PPFA fractions (>10 kDa) possessed more aromatic and hydrophobic components, displayed a higher degree of humification, and exhibited higher metal binding potential. Furthermore, the speciation analysis and stability constant (cK) were calculated using Donnan membrane equilibrium. The correlation between cK values and PPFA spectral properties demonstrated that aromaticity, hydrophobicity, molecular weight and humification degree were crucial indices of PPFA−Fe(III) affinity. Significantly, the humification degree, represented by HIX, showed the strongest correlation (r = 0.929, p = 0.003), which could be used to estimate the binding strength. This study provides further understanding of the complexation mechanism of iron and DOM in the peat environment and identifies the considerable effect of molecular weight.
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Affiliation(s)
- Yaqin Zhang
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
| | - Chang Liu
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
| | - Yuxia Li
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
| | - Liuting Song
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
- Correspondence: (L.S.); (J.Y.)
| | - Jie Yang
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
- Correspondence: (L.S.); (J.Y.)
| | - Rui Zuo
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
| | - Jian Li
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
| | - Yanguo Teng
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
| | - Jinsheng Wang
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; (Y.Z.); (C.L.); (Y.L.); (R.Z.); (J.L.); (Y.T.); (J.W.)
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, China
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Klaes B, Wörner G, Thiele-Bruhn S, Arz HW, Struck J, Dellwig O, Groschopf N, Lorenz M, Wagner JF, Urrea OB, Lamy F, Kilian R. Element mobility related to rock weathering and soil formation at the westward side of the southernmost Patagonian Andes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 817:152977. [PMID: 35016939 DOI: 10.1016/j.scitotenv.2022.152977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/25/2021] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Rock weathering and pedogenesis are fundamental processes for element mobility in terrestrial bio-geochemical cycles and for the regulation of primary productivity in adjacent coastal marine ecosystems. Here, soils developed from volcanic ash under extreme climate conditions could play a particular role. We therefore investigated rock weathering, soil formation and the associated mobilization of trace elements and micronutrients in a pristine South Patagonian ecosystem. Weathered and unweathered basement lithologies, tephra of the 4.216 kyrs BP Mt. Burney eruption and four soil profiles are considered. The approach combines mineralogical (XRD, SEM) and inorganic geochemical (XRF, ICP-OES/MS) with organic geochemical analyses (TOC, TN, δ13C, δ15N, DOC extracts) of representative samples. Chemical weathering is quantified by mass balance calculations and 14C age constraints allow a correlation of pedogenic processes with the paleoenvironmental history of the area. Our data document that pedogenesis with initial peat formation occurred since ~2.5 kyrs BP. In these acidic peaty Andosols, intensive alteration of volcanic glass mobilized large quantities of elements, considerably surpassing leachates provided by basement rock weathering. Clay production is limited in favor of the formation of amorphous Al- and crystalline Fe-(hydr)oxides. However, tephra alteration, soil organic matter turnover rates, enhanced dissolved organic carbon export, and Fe-/Al-(hydr)oxide precipitation are closely linked and ultimately controlled by rainfall-induced water-level fluctuations, highlighting the dominant influence of the southern westerly wind belt. The transport of mobilized trace elements and micronutrients adsorbed onto suspended colloids (dissolved organic carbon, Al-humus complexes and Fe-(hydr)oxides) is redox-pH-dependent, highly variable and ultimately regulated by westerly intensity. Broader implications of this work include a new perspective on the climate-controlled micronutrient delivery for primary productivity in South Patagonian fjords, which is strongly affected by Andosol formation. Furthermore, a careful evaluation of 'ordinary' geochemical proxies in regional paleoenvironmental archives is needed to account for these unique pedogenic processes.
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Affiliation(s)
- Björn Klaes
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany; Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Gerhard Wörner
- Division of Geochemistry and Isotope Geology, GZG, Georg-August-University Göttingen, Goldschmidtstraße 1, 37077 Göttingen, Germany.
| | - Sören Thiele-Bruhn
- Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Helge Wolfgang Arz
- Marine Geology Department, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Seestraße 15, 18119 Rostock, Germany.
| | - Julian Struck
- Department of Physical Geography, Institute of Geography, Friedrich-Schiller-University Jena, Löbdergraben 32, 07743 Jena, Germany.
| | - Olaf Dellwig
- Marine Geology Department, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Seestraße 15, 18119 Rostock, Germany.
| | - Nora Groschopf
- Petrology Research Group, Institute of Geosciences, Johannes Gutenberg University Mainz, Johann-Joachim-Becher-Weg 21, 55128 Mainz, Germany.
| | - Marcel Lorenz
- Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Jean-Frank Wagner
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Oscar Baeza Urrea
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Frank Lamy
- Alfred Wegener Institute (AWI) Bremerhaven, Am Alten Hafen 26, 27568 Bremerhaven, Germany.
| | - Rolf Kilian
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany; University of Magallanes, Avenida Bulnes, 01855 Punta Arenas, Chile
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5
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Krachler R, Krachler RF. Northern High-Latitude Organic Soils As a Vital Source of River-Borne Dissolved Iron to the Ocean. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9672-9690. [PMID: 34251212 DOI: 10.1021/acs.est.1c01439] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Organic soils in the Arctic-boreal region produce small aquatic humic ligands (SAHLs), a category of naturally occurring complexing agents for iron. Every year, large amounts of SAHLs-loaded with iron mobilized in river basins-reach the oceans via river runoff. Recent studies have shown that a fraction of SAHLs belong to the group of strong iron-binding ligands in the ocean. That means, their Fe(III) complexes withstand dissociation even under the conditions of extremely high dilution in the open ocean. Fe(III)-loaded SAHLs are prone to UV-photoinduced ligand-to-metal charge-transfer which leads to disintegration of the complex and, as a consequence, to enhanced concentrations of bioavailable dissolved Fe(II) in sunlit upper water layers. On the other hand, in water depths below the penetration depth of UV, the Fe(III)-loaded SAHLs are fairly resistant to degradation which makes them ideally suited as long-lived molecular transport vehicles for river-derived iron in ocean currents. At locations where SAHLs are present in excess, they can bind to iron originating from various sources. For example, SAHLs were proposed to contribute substantially to the stabilization of hydrothermal iron in deep North Atlantic waters. Recent discoveries have shown that SAHLs, supplied by the Arctic Great Rivers, greatly improve dissolved iron concentrations in the Arctic Ocean and the North Atlantic Ocean. In these regions, SAHLs play a critical role in relieving iron limitation of phytoplankton, thereby supporting the oceanic sink for anthropogenic CO2. The present Critical Review describes the most recent findings and highlights future research directions.
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Affiliation(s)
- Regina Krachler
- Institute of Inorganic Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; http://anorg-chemie.univie.ac.at
| | - Rudolf F Krachler
- Institute of Inorganic Chemistry, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; http://anorg-chemie.univie.ac.at
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D’Alelio D, Russo L, Hay Mele B, Pomati F. Intersecting Ecosystem Services Across the Aquatic Continuum: From Global Change Impacts to Local, and Biologically Driven, Synergies and Trade-Offs. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.628658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The study of ecosystem services requires the integration of different observational points. This is particularly true in Water, as this element continuously cycles, increasing chances of interaction among services originating in different ecosystems. However, aquatic scientists historically approached the study of inland/freshwater and open/marine waters in different ways and this cultural division potentially hampers integrative approaches. Herein, we explored the literature pertaining to ecosystem services across the last 23 years, analysing 4,590 aquatic papers. By aggregating and intersecting topics included in this papers’ collection using text-mining and topical network approaches, we saw that the study of local environmental conditions (e.g., river estuary management) and synergies and trade-offs between services (e.g., carbon sequestration and water purification) can display several potential conceptual links between freshwater and marine sciences. Our analyses suggest that to intersect ecosystem services across the aquatic continuum, the conceptual integration between marine and freshwater science must be reinforced, especially at the interface between different “salinity realms.” Such integration should adopt a “system thinking” perspective, in which the focus is on multiple socio-ecological processes giving rise to interactions that are (i) biologically mediated, (ii) potentially conflicting, and (iii) entangled within networks.
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Liu J, Qiu Y, He L, Luo K, Wang Z. Effect of iron and phosphorus on the microalgae growth in co-culture. Arch Microbiol 2020; 203:733-740. [PMID: 33044622 DOI: 10.1007/s00203-020-02074-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 07/12/2020] [Accepted: 10/01/2020] [Indexed: 11/28/2022]
Abstract
Iron and phosphorus (P) are the important micro- and macro-nutrient for microalgae growth, respectively. However, the effect of iron and P on microalgae growth in co-culture associating with the formation of dominate algae has not been investigated before. In the current study, Anabaene flos-aquae, Chlorella vulgaris and Melosira sp. were co-cultivated under the addition of different initial iron and P to reveal the effect of iron and phosphorus on the growth of microalgae. The results showed that the mean growth rate of A. flos-aquae, C. vulgaris and Melosira was 0.270, 0.261 and 0.062, respectively, indicating that the A. flos-aquae and C. vulgaris algae are liable to be the dominant algae while the growth of Melosira was restrained when co-cultured. The ratio of Fe to P has a significant impact on the growth of microalgae and could be regarded as an indicator of algae growth. Microalgae showed a much more obvious uptake of iron compared to that of P. The information obtained in the current study was useful for the forecast of water quality and the control of microalgae bloom.
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Affiliation(s)
- Junxia Liu
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Yongting Qiu
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Linjuan He
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Keshu Luo
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Zhihong Wang
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
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Krachler R, Krachler R, Valda A, Keppler BK. Natural iron fertilization of the coastal ocean by "blackwater rivers". THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 656:952-958. [PMID: 30625681 DOI: 10.1016/j.scitotenv.2018.11.423] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 11/16/2018] [Accepted: 11/28/2018] [Indexed: 05/23/2023]
Abstract
The present study elucidates the role of natural iron fertilization of the coastal ocean by so-called "blackwater rivers". Areas of marsh, fen, peatland, boreal forest etc. are characterized by organic-rich soils. From those soils, humic substances (humic and fulvic acids) are leached to the aquatic system resulting in river water that is low in pH and dark-brown in color. The point is that "blackwater rivers" tend to be rich in dissolved iron due to the unique chelating properties of humic and fulvic acids which bind Fe(III) and keep it in solution. We performed algal physiological (growth rate) experiments under conditions of iron deficiency with the marine unicellular phytoplankton algae Chlorella salina and Diacronema lutheri in 0.2 μm cut-off filtered mixtures of natural "blackwater river" water and synthetic seawater. Our results demonstrate that the iron naturally present in "blackwater rivers" is readily bioavailable to both marine algal species. Furthermore, the humic and fulvic acids exert an additional stimulatory effect on the marine algae. Both algae thrive much better in the presence of natural humic and fulvic acids as compared to a medium where EDTA is used as an iron-chelating agent. Our results indicate that "blackwater rivers", in sharp contrast to other types of rivers, are excellent sources of bioavailable iron to marine phytoplankton. This natural iron fertilization may give rise to photosynthesis-driven sequestration of CO2 from the atmosphere to the sea, as can be seen from the visualization of CO2 surface concentrations by NASA (NASA GEOS-5 model) which shows the global sources and sinks of CO2 localized in time and space. The results by NASA suggest that strong marine CO2 sinks in coastal waters tend to occur close to "blackwater river" estuaries. It is thus evident that "blackwater rivers" act as important sources of a limiting nutrient (iron) to the ocean.
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Affiliation(s)
- Regina Krachler
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Währingerstrasse 42, A-1090 Vienna, Austria.
| | - Rudolf Krachler
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Währingerstrasse 42, A-1090 Vienna, Austria
| | - Alexander Valda
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Währingerstrasse 42, A-1090 Vienna, Austria
| | - Bernhard K Keppler
- University of Vienna, Faculty of Chemistry, Institute of Inorganic Chemistry, Währingerstrasse 42, A-1090 Vienna, Austria
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Muller FLL, Cuscov M. Alteration of the Copper-Binding Capacity of Iron-Rich Humic Colloids during Transport from Peatland to Marine Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:3214-3222. [PMID: 28218520 DOI: 10.1021/acs.est.6b05303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Blanket bogs contain vast amounts of Sphagnum-derived organic substances which can act as powerful chelators for dissolved iron and thus enhance its export to the coastal ocean. To investigate the variations in quantity and quality of these exports, adsorptive cathodic stripping voltammetry (CSV) was used to characterize the metal binding properties of molecular weight-fractionated dissolved organic matter (MW-fractionated DOM) in the catchment and coastal plume of a small peat-draining river over a seasonal cycle. Within the plume, both iron- and copper-binding organic ligands showed a linear, conservative distribution with increasing salinity, illustrating the high stability of peatland-derived humic substances (HS). Within the catchment, humic colloids lost up to 50% of their copper-binding capacity, expressed as a molar ratio to organic carbon, after residing for 1 week or more in the main reservoir of the catchment. Immediately downstream of the reservoir, the molar ratio [L2]/[Corg], where L2 was the second strongest copper-binding ligand, was 0.75 × 10-4 when the reservoir residence time was 5 h but 0.34 × 10-4 when it was 25 days. Residence time did not affect the carbon specific iron-binding capacity of the humic substances which was [L]/[Corg] = (0.80 ± 0.20) × 10-2. Our results suggest that the loss of copper-binding capacity with increasing residence time is caused by intracolloidal interactions between iron and HS during transit from peat soil to river mouth.
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Affiliation(s)
- François L L Muller
- Environmental Research Institute, University of the Highlands and Islands , Castle Street, Thurso KW14 7JD, United Kingdom
| | - Marco Cuscov
- Environmental Research Institute, University of the Highlands and Islands , Castle Street, Thurso KW14 7JD, United Kingdom
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10
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Orlowska E, Roller A, Pignitter M, Jirsa F, Krachler R, Kandioller W, Keppler BK. Synthetic iron complexes as models for natural iron-humic compounds: Synthesis, characterization and algal growth experiments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 577:94-104. [PMID: 27810305 DOI: 10.1016/j.scitotenv.2016.10.109] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/14/2016] [Accepted: 10/15/2016] [Indexed: 06/06/2023]
Abstract
A series of monomeric and dimeric FeIII complexes with O,O-; O,N-; O,S-coordination motifs has been prepared and characterized by standard analytical methods in order to elucidate their potential to act as model compounds for aquatic humic acids. Due to the postulated reduction of iron in humic acids and following uptake by microorganisms, the redox behavior of the models was investigated with cyclic voltammetry. Most of the investigated compounds showed iron reduction potentials accessible to biological reducing agents. Additionally, observed reduction processes were predominantly irreversible, suggesting that subsequent reactions can take place after reduction of the iron center. Also the stability of the synthesized complexes in pure water and artificial seawater was monitored from 24h up to 21days by means of UV-Vis spectrometry. Several complexes remained stable even after 21days, showing only partially precipitation but some of them showed changes in UV-Vis spectra already after 24h which were connected to protonation/deprotonation processes as well as redox processes and degradation of the complexes. The ability to act as an iron source for primary producers was tested in algal growth experiments with two marine algae species Chlorella salina and Prymnesium parvum. Some of the compounds showed effects on the algal cultures, which are comparable with natural humic acids and better as for the samples kept under ideal conditions. Those findings help to understand which functional groups of humic acids could be responsible for the reversible iron binding and transport in aquatic humic substances.
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Affiliation(s)
- Ewelina Orlowska
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria
| | - Alexander Roller
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria
| | - Marc Pignitter
- Department of Nutritional and Physiological Chemistry, Faculty of Chemistry, University of Vienna, Althanstr. 14/UZA II, A-1090 Vienna, Austria
| | - Franz Jirsa
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria; Department of Zoology, University of Johannesburg, Auckland Park 2006, South Africa
| | - Regina Krachler
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria
| | - Wolfgang Kandioller
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria.
| | - Bernhard K Keppler
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria
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Orlowska E, Enyedy ÉA, Pignitter M, Jirsa F, Krachler R, Kandioller W, Keppler BK. β-O-4 type dilignol compounds and their iron complexes for modeling of iron binding to humic acids: synthesis, characterization, electrochemical studies and algal growth experiments. NEW J CHEM 2017. [DOI: 10.1039/c7nj02328f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of β-O-4 type dilignols and their iron(iii) complexes were evaluated as model compounds for humic acids.
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Affiliation(s)
- Ewelina Orlowska
- Institute of Inorganic Chemistry
- Faculty of Chemistry
- University of Vienna
- A-1090 Vienna
- Austria
| | - Éva A. Enyedy
- Department of Inorganic and Analytical Chemistry
- University of Szeged
- H-6720 Szeged
- Hungary
| | - Marc Pignitter
- Department of Physiological Chemistry
- Faculty of Chemistry
- University of Vienna
- A-1090 Vienna
- Austria
| | - Franz Jirsa
- Institute of Inorganic Chemistry
- Faculty of Chemistry
- University of Vienna
- A-1090 Vienna
- Austria
| | - Regina Krachler
- Institute of Inorganic Chemistry
- Faculty of Chemistry
- University of Vienna
- A-1090 Vienna
- Austria
| | - Wolfgang Kandioller
- Institute of Inorganic Chemistry
- Faculty of Chemistry
- University of Vienna
- A-1090 Vienna
- Austria
| | - Bernhard K. Keppler
- Institute of Inorganic Chemistry
- Faculty of Chemistry
- University of Vienna
- A-1090 Vienna
- Austria
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