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Article ; Online: Coprecipitation of Phosphate and Silicate Affects Environmental Iron (Oxyhydr)Oxide Transformations: A Gel-Based Diffusive Sampler Approach.

Kraal, Peter / van Genuchten, Case M / Lenstra, Wytze K / Behrends, Thilo

Environmental science & technology

2020 Volume 54, Issue 19, Page(s) 12795–12802

Abstract: Sorption of nutrients such as phosphate (P) and silicate (Si) by ferric iron (oxyhydr)oxides (FeOx) modulates nutrient mobility and alters the structure and reactivity of the FeOx. We investigated the impact of these interactions on FeOx transformations ... ...

Abstract	Sorption of nutrients such as phosphate (P) and silicate (Si) by ferric iron (oxyhydr)oxides (FeOx) modulates nutrient mobility and alters the structure and reactivity of the FeOx. We investigated the impact of these interactions on FeOx transformations using a novel approach with samplers containing synthetic FeOx embedded in diffusive hydrogels. The FeOx were prepared by Fe(III) hydrolysis and Fe(II) oxidation, in the absence and presence of P or Si. Coprecipitation of P or Si during synthesis altered the structure of Fe precipitates and, in the case of Fe(II) oxidation, lepidocrocite was (partly) substituted by poorly ordered FeOx. The pure and P- or Si-bearing FeOx were deployed in (i) freshwater sediment rich in dissolved Fe(II) and P and (ii) marine sediment with sulfidic pore water. Iron(II)-catalyzed crystallization of poorly ordered FeOx was negligible, likely due to surface passivation by adsorption of dissolved P. Reaction with dissolved sulfide was modulated by diffusion limitations and therefore the extent of sulfidation was the lowest for poorly ordered FeOx with high reactivity toward sulfide that created temporary, local sulfide depletion (Fh < Lp). We show that coprecipitation-induced changes in the FeOx structure affect coupled iron-nutrient cycling in aquatic ecosystems. The gel-based method enriches our geochemical toolbox by enabling detailed characterization of target phases under natural conditions.
MeSH term(s)	Ecosystem ; Ferric Compounds ; Iron ; Oxidation-Reduction ; Oxides ; Phosphates ; Silicates
Chemical Substances	Ferric Compounds ; Oxides ; Phosphates ; Silicates ; Iron (E1UOL152H7)
Language	English
Publishing date	2020-09-17
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1520-5851
ISSN (online)	1520-5851
DOI	10.1021/acs.est.0c02352
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Coprecipitation of Phosphate and Silicate Affects Environmental Iron (Oxyhydr)Oxide Transformations: A Gel-Based Diffusive Sampler Approach

Kraal, Peter / van Genuchten, Case M / Lenstra, Wytze K / Behrends, Thilo

Environmental science & technology. 2020 Sept. 04, v. 54, no. 19

2020

Abstract	Sorption of nutrients such as phosphate (P) and silicate (Si) by ferric iron (oxyhydr)oxides (FeOx) modulates nutrient mobility and alters the structure and reactivity of the FeOx. We investigated the impact of these interactions on FeOx transformations using a novel approach with samplers containing synthetic FeOx embedded in diffusive hydrogels. The FeOx were prepared by Fe(III) hydrolysis and Fe(II) oxidation, in the absence and presence of P or Si. Coprecipitation of P or Si during synthesis altered the structure of Fe precipitates and, in the case of Fe(II) oxidation, lepidocrocite was (partly) substituted by poorly ordered FeOx. The pure and P- or Si-bearing FeOx were deployed in (i) freshwater sediment rich in dissolved Fe(II) and P and (ii) marine sediment with sulfidic pore water. Iron(II)-catalyzed crystallization of poorly ordered FeOx was negligible, likely due to surface passivation by adsorption of dissolved P. Reaction with dissolved sulfide was modulated by diffusion limitations and therefore the extent of sulfidation was the lowest for poorly ordered FeOx with high reactivity toward sulfide that created temporary, local sulfide depletion (Fh < Lp). We show that coprecipitation-induced changes in the FeOx structure affect coupled iron-nutrient cycling in aquatic ecosystems. The gel-based method enriches our geochemical toolbox by enabling detailed characterization of target phases under natural conditions.
Keywords	adsorption ; coprecipitation ; crystallization ; environmental science ; freshwater ; hydrogels ; hydrolysis ; iron ; lepidocrocite ; marine sediments ; oxidation ; phosphates ; silicates ; sulfides ; technology
Language	English
Dates of publication	2020-0904
Size	p. 12795-12802.
Publishing place	American Chemical Society
Document type	Article
Note	NAL-AP-2-clean
ISSN	1520-5851
DOI	10.1021/acs.est.0c02352
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Sorption of phosphate and silicate alters dissolution kinetics of poorly crystalline iron (oxyhydr)oxide.

Kraal, Peter / van Genuchten, Case M / Behrends, Thilo / Rose, Andrew L

Chemosphere

2019 Volume 234, Page(s) 690–701

Abstract: Iron (oxyhydr)oxides (FeOx) control retention of dissolved nutrients and contaminants in aquatic systems. However, FeOx structure and reactivity is dependent on adsorption and incorporation of such dissolved species, particularly oxyanions such as ... ...

Abstract	Iron (oxyhydr)oxides (FeOx) control retention of dissolved nutrients and contaminants in aquatic systems. However, FeOx structure and reactivity is dependent on adsorption and incorporation of such dissolved species, particularly oxyanions such as phosphate and silicate. These interactions affect the fate of nutrients and metal(loids), especially in perturbed aquatic environments such as eutrophic coastal systems and environments impacted by acid mine drainage. Altered FeOx reactivity impacts sedimentary nutrient retention capacity and, eventually, ecosystem trophic state. Here, we explore the influence of phosphate (P) and silicate (Si) on FeOx structure and reactivity. Synthetic, poorly crystalline FeOx with adsorbed and coprecipitated phosphate or silicate at low but environmentally relevant P/Fe or Si/Fe ratios (0.02-0.1 mol mol
MeSH term(s)	Adsorption ; Ecosystem ; Environmental Pollutants/analysis ; Environmental Pollutants/chemistry ; Ferric Compounds/chemistry ; Kinetics ; Phosphates/analysis ; Phosphates/chemistry ; Silicates/analysis ; Silicates/chemistry ; Solubility ; Water Pollutants, Chemical/analysis ; Water Pollutants, Chemical/chemistry
Chemical Substances	Environmental Pollutants ; Ferric Compounds ; Phosphates ; Silicates ; Water Pollutants, Chemical ; ferric oxide (1K09F3G675)
Language	English
Publishing date	2019-06-21
Publishing country	England
Document type	Journal Article
ZDB-ID	120089-6
ISSN	1879-1298 ; 0045-6535 ; 0366-7111
ISSN (online)	1879-1298
ISSN	0045-6535 ; 0366-7111
DOI	10.1016/j.chemosphere.2019.06.071
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Rapid and extensive alteration of phosphorus speciation during oxic storage of wet sediment samples.

Kraal, Peter / Slomp, Caroline P

PloS one

2014 Volume 9, Issue 5, Page(s) e96859

Abstract: The chemical forms of phosphorus (P) in sediments are routinely measured in studies of P in modern and ancient marine environments. However, samples for such analyses are often exposed to atmospheric oxygen during storage and handling. Recent work ... ...

Abstract	The chemical forms of phosphorus (P) in sediments are routinely measured in studies of P in modern and ancient marine environments. However, samples for such analyses are often exposed to atmospheric oxygen during storage and handling. Recent work suggests that long-term exposure of pyrite-bearing sediments can lead to a decline in apatite P and an increase in ferric Fe-bound P. Here, we report on alterations in P speciation in reducing modern Baltic Sea sediments that we deliberately exposed to atmospheric oxygen for a period of either one week or one year. During oxidation of the sediment, extensive changes occurred in all measured P reservoirs. Exchangeable P all but disappeared during the first week of exposure, likely reflecting adsorption of porewater PO4 by Fe(III) (oxyhydr)oxides (i.e. ferric Fe-bound P formation). Detrital and organic P were also rapidly affected: decreases in both reservoirs were already observed after the first week of exposure to atmospheric oxygen. This was likely because of acidic dissolution of detrital apatite and oxidation of organic matter, respectively. These processes produced dissolved PO4 that was then scavenged by Fe(III) (oxyhydr)oxides. Interestingly, P in authigenic calcium phosphates (i.e. apatite: authigenic Ca-P) remained unaffected after the first week of exposure, which we attributed to the shielding effect of microfossils in which authigenic Ca-P occurs in Baltic Sea sediments. This effect was transient; a marked decrease in the authigenic Ca-P pool was observed in the sediments after one year of exposure to oxygen. In summary, we show that handling and storage of wet sediments under oxic conditions can lead to rapid and extensive alteration of the original sediment P speciation.
MeSH term(s)	Calcium Phosphates/chemistry ; Ferric Compounds/chemistry ; Geologic Sediments/chemistry ; Iron/chemistry ; Oxidation-Reduction ; Oxygen/chemistry ; Phosphorus/chemistry ; Sulfides/chemistry ; Water Pollutants, Chemical/chemistry
Chemical Substances	Calcium Phosphates ; Ferric Compounds ; Sulfides ; Water Pollutants, Chemical ; pyrite (132N09W4PR) ; Phosphorus (27YLU75U4W) ; Iron (E1UOL152H7) ; ferric phosphate (N6BAA189V1) ; Oxygen (S88TT14065)
Language	English
Publishing date	2014-05-06
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1932-6203
ISSN (online)	1932-6203
DOI	10.1371/journal.pone.0096859
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Phosphate loading alters schwertmannite transformation rates and pathways during microbial reduction.

Schoepfer, Valerie A / Burton, Edward D / Johnston, Scott G / Kraal, Peter

The Science of the total environment

2018 Volume 657, Page(s) 770–780

Abstract: Acid sulfate systems commonly contain the metastable ferric oxyhydroxysulfate mineral schwertmannite, as well as phosphate ( ... ...

Abstract	Acid sulfate systems commonly contain the metastable ferric oxyhydroxysulfate mineral schwertmannite, as well as phosphate (PO
MeSH term(s)	Biotransformation ; Hydrogen-Ion Concentration ; Iron/chemistry ; Iron/metabolism ; Iron Compounds/chemistry ; Iron Compounds/metabolism ; Microbial Consortia/physiology ; Microscopy, Electron, Scanning ; Phosphates/chemistry ; Sulfates/chemistry ; Water Pollutants, Chemical/chemistry ; Water Purification/methods ; X-Ray Absorption Spectroscopy ; X-Ray Diffraction
Chemical Substances	Iron Compounds ; Phosphates ; Sulfates ; Water Pollutants, Chemical ; schwertmannite ; Iron (E1UOL152H7)
Language	English
Publishing date	2018-12-07
Publishing country	Netherlands
Document type	Journal Article
ZDB-ID	121506-1
ISSN	1879-1026 ; 0048-9697
ISSN (online)	1879-1026
ISSN	0048-9697
DOI	10.1016/j.scitotenv.2018.12.082
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Article: Makonde

Kraal, Peter

Coding Participant Marking#Amsterdam::BenjaminsISBN978-90-272-0577-3 , p. 281-305

2009 , Page(s) 281–305

Author's details	Peter Kraal
Language	English
Document type	Article
Database	Former special subject collection: coastal and deep sea fishing

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Article ; Online: Turbidite deposition and diagenesis in the southwestern Black Sea

Kraal, Peter / Yücel, Mustafa / Slomp, Caroline P.

Implications for biogeochemical cycling in an anoxic basin

2019

Abstract: Highlights • Turbidity currents transport large amounts of reactive iron minerals and associated phosphorus into the Black Sea deep basin • Sediments on the southwestern shelf enriched in reactive ferrous and ferric iron are suggested as turbidite source ...

Abstract	Highlights • Turbidity currents transport large amounts of reactive iron minerals and associated phosphorus into the Black Sea deep basin • Sediments on the southwestern shelf enriched in reactive ferrous and ferric iron are suggested as turbidite source area • Iron sulfidation in and phosphorus release from turbidity currents in deep waters affect iron, phosphorus and sulfur budgets • The original redox signature of the source sediment can be preserved in turbidites for longer than expected Abstract The biogeochemical cycles of iron, phosphorus and sulfur are intimately linked and the fate of these elements is highly redox-dependent. Under anoxic conditions, iron is reduced to Fe(II), for an important part driven by reaction with sulfide. Reduction and sulfidation diminish the affinity of iron for phosphorus, thereby affecting sedimentary phosphorus retention. The coupled cycling of iron-phosphorus-sulfur as a function of redox conditions thereby helps control nutrient availability and primary productivity in marine systems. The Black Sea is the world's largest permanently stratified basin with a strong gradient from oxic surface waters to anoxic and strongly sulfidic deep waters, and is therefore well-suited to investigate redox-dependent changes in coupled iron-phosphorus-sulfur cycling. The presence of sulfide in the deep Black Sea alters the chemical speciation of iron (Fe) and phosphorus (P) in particulate matter in the water column and sediment. These alterations and their impact are poorly constrained for turbidites, which are deposits formed by mass transport from the continental slope into the deep basin of the Black Sea through turbidity currents. Here, we compare the geochemistry of sediments on the southwestern (SW) Black Sea slope overlain by oxygenated waters (234 m below sea surface, mbss) with that of a sediment record with turbidite intervals from the sulfidic SW deep basin (2169 mbss). The aims were to investigate the potential of SW slope sediment as source material for turbidites, and to ...
Subject code	550 ; 551
Language	English
Publisher	Elsevier
Publishing country	de
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Sorption of phosphate and silicate alters dissolution kinetics of poorly crystalline iron (oxyhydr)oxide

Kraal, Peter / van Genuchten, Case M / Behrends, Thilo / Rose, Andrew L

Chemosphere. 2019 Nov., v. 234

2019

Abstract	Iron (oxyhydr)oxides (FeOx) control retention of dissolved nutrients and contaminants in aquatic systems. However, FeOx structure and reactivity is dependent on adsorption and incorporation of such dissolved species, particularly oxyanions such as phosphate and silicate. These interactions affect the fate of nutrients and metal(loids), especially in perturbed aquatic environments such as eutrophic coastal systems and environments impacted by acid mine drainage. Altered FeOx reactivity impacts sedimentary nutrient retention capacity and, eventually, ecosystem trophic state. Here, we explore the influence of phosphate (P) and silicate (Si) on FeOx structure and reactivity. Synthetic, poorly crystalline FeOx with adsorbed and coprecipitated phosphate or silicate at low but environmentally relevant P/Fe or Si/Fe ratios (0.02–0.1 mol mol−1) was prepared by base titration of Fe(III) solutions. Structural characteristics of FeOx were investigated by X-ray diffraction, synchrotron-based X-ray absorption spectroscopy and high-energy X-ray scattering. Reactivity of FeOx was assessed by kinetic dissolution experiments under acidic (dilute HCl, pH 2) and circum-neutral reducing (bicarbonate-buffered ascorbic acid, pH 7.8, Eh ∼ −300 mV) conditions. At these loadings, phosphate and silicate coprecipitation had only slight impact on local and intermediate-ranged FeOx structure, but significantly enhanced the dissolution rate of FeOx. Conversely, phosphate and silicate adsorption at similar loadings resulted in particle surface passivation and decreased FeOx dissolution rates. These findings indicate that varying nutrient loadings and different interaction mechanisms between anions and FeOx (adsorption versus coprecipitation) can influence the broader biogeochemical functioning of aquatic ecosystems by impacting the structure and reactivity of FeOx.
Keywords	X-ray absorption spectroscopy ; X-ray diffraction ; acid mine drainage ; adsorption ; aquatic ecosystems ; aquatic environment ; ascorbic acid ; coprecipitation ; eutrophication ; hydrochloric acid ; iron ; iron oxyhydroxides ; nutrient retention ; nutrients ; oxides ; oxyanions ; pH ; phosphates ; pollution load ; silicates ; silicon ; titration
Language	English
Dates of publication	2019-11
Size	p. 690-701.
Publishing place	Elsevier Ltd
Document type	Article
ZDB-ID	120089-6
ISSN	1879-1298 ; 0045-6535 ; 0366-7111
ISSN (online)	1879-1298
ISSN	0045-6535 ; 0366-7111
DOI	10.1016/j.chemosphere.2019.06.071
Database	NAL-Catalogue (AGRICOLA)

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Zs.A 2540: Show issues

Location:
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Jg. 1995 - 2021: Lesesall (2.OG)
ab Jg. 2022: Lesesaal (EG)

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Article ; Online: Phosphate-Imposed Constraints on Schwertmannite Stability under Reducing Conditions.

Schoepfer, Valerie A / Burton, Edward D / Johnston, Scott G / Kraal, Peter

Environmental science & technology

2017 Volume 51, Issue 17, Page(s) 9739–9746

Abstract: Schwertmannite is a ferric oxyhydroxysulfate mineral, which is common in acid sulfate systems. Such systems contain varying concentrations of phosphate ( ... ...

Abstract	Schwertmannite is a ferric oxyhydroxysulfate mineral, which is common in acid sulfate systems. Such systems contain varying concentrations of phosphate (PO
Language	English
Publishing date	2017-09-05
Publishing country	United States
Document type	Journal Article
ISSN	1520-5851
ISSN (online)	1520-5851
DOI	10.1021/acs.est.7b02103
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Book ; Online: Bacteriohopanetetrol-x

Kemenade, Zoë R. / Villanueva, Laura / Hopmans, Ellen C. / Kraal, Peter / Witte, Harry J. / Sinninghe Damsté, Jaap S. / Rush, Darci

eISSN: 1726-4189

constraining its application as a lipid biomarker for marine anammox using the water column oxygen gradient of the Benguela upwelling system

2022

Abstract: Interpreting lipid biomarkers in the sediment archive requires a good understanding of their application and limitations in modern systems. Recently it was discovered that marine bacteria performing anaerobic ammonium oxidation (anammox), belonging to ... ...

Abstract	Interpreting lipid biomarkers in the sediment archive requires a good understanding of their application and limitations in modern systems. Recently it was discovered that marine bacteria performing anaerobic ammonium oxidation (anammox), belonging to the genus Ca. Scalindua, uniquely synthesize a stereoisomer of bacteriohopanetetrol (“BHT- x ”). The ratio of BHT- x over total bacteriohopanetetrol (BHT, ubiquitously synthesized by diverse bacteria) has been suggested as a proxy for water column anoxia. As BHT has been found in sediments over 50 Myr old, BHT- x has the potential to complement and extend the sedimentary biomarker record of marine anammox, conventionally constructed using ladderane lipids. Yet, little is known about the distribution of BHT- x in relation to the distribution of ladderanes and to the genetic evidence of Ca. Scalindua in modern marine systems. Here, we investigate the distribution of BHT- x and the application of the BHT- x ratio in relation to distributions of ladderane intact polar lipids (IPLs), ladderane fatty acids (FAs) and Ca. Scalindua 16S rRNA genes in suspended particulate matter (SPM) from the water column of the Benguela upwelling system (BUS), sampled across a large oxygen gradient. In BUS SPM, high BHT- x abundances were restricted to the oxygen-deficient zone on the continental shelf (at [O 2 ] < 45 µ mol L −1 , in all but one case). High BHT- x abundances co-occurred with high abundances of the Ca. Scalindua 16S rRNA gene (relative to the total number of bacterial 16S rRNA genes) and ladderane IPLs. At shelf stations with [O 2 ] > 50 µ mol L −1 , the BHT- x ratio was < 0.04 (in all but one case). In apparent contradiction, ladderane FAs and low abundances of BHT and BHT- x (resulting in BHT- x ratios > 0.04) were also detected in oxygenated offshore waters ([O 2 ] up to 180 µ mol L −1 ), whereas ladderane IPLs were undetected. The index of ladderane lipids with five cyclobutane rings (NL 5 ) correlates with in situ temperature. NL 5 -derived temperatures suggested that ladderane FAs in the offshore waters were not synthesized in situ but were transported down-slope from warmer shelf waters. Thus, in sedimentary archives of systems with known lateral organic matter transport, such as the BUS, relative BHT and BHT- x abundances should be carefully considered. In such systems, a higher BHT- x ratio may act as a safer threshold for deoxygenation and/or Ca. Scalindua presence: our results and previous studies indicate that a BHT- x ratio of ≥ 0.2 is a robust threshold for oxygen-depleted waters ([O 2 ] < 50 µ mol kg −1 ). In our data, ratios of ≥ 0.2 coincided with Ca. Scalindua 16S rRNA genes in all samples ( n =62 ), except one. Lastly, when investigating in situ anammox, we highlight the importance of using ladderane IPLs over BHT- x and/or ladderane FAs; these latter compounds are more recalcitrant and may derive from transported fossil anammox bacteria remnants.
Subject code	511 ; 333
Language	English
Publishing date	2022-01-13
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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