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Lee YP, Fujii M, Kikuchi T, Natsuike M, Ito H, Watanabe T, Yoshimura C. Importance of allochthonous and autochthonous dissolved organic matter in Fe(II) oxidation: A case study in Shizugawa Bay watershed, Japan. CHEMOSPHERE 2017; 180:221-228. [PMID: 28410502 DOI: 10.1016/j.chemosphere.2017.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/30/2017] [Accepted: 04/02/2017] [Indexed: 06/07/2023]
Abstract
Ferrous iron (Fe[II]) oxidation by dissolved oxygen was investigated in the Shizugawa Bay watershed with particular attention given to the effect of dissolved organic matter (DOM) properties on Fe(II) oxidation. To cover a wide spectrum of DOM composition, water samples were collected from various water sources including freshwater (e.g., river water and wastewater effluent) and coastal seawater. Measurement of nanomolar Fe(II) oxidation by using luminol chemiluminescence under dark, air-saturated conditions at 25 °C indicated that spatio-temporal variation of the second-order rate constant (6.7-74.5 M-1 s-1) was partially explained by the variation of the sample pH (7.5-8.6). However, at comparable pH values, the oxidation rates for freshwater were generally greater than those for coastal seawater. The substantial decline in oxidation rate constant after the removal of humic-type (allochthonous) DOM suggested that this hydrophobic DOM is a key factor that accelerates the Fe(II) oxidation in the freshwater samples. Observed lower oxidation rates for coastal seawater compared with freshwater and organic ligand-free seawater were likely associated with microbially derived autochthonous DOM, and the variation of Fe(II) oxidation at a fixed pH was best described by fluorescence index that represents the proportion of autochthonous and allochthonous DOM in natural waters. Consistently, Fe(II) oxidation was found to be slower in the presence of cellular exudates from phytoplankton. The present study highlighted the significant effect of DOM composition on the Fe(II) oxidation in inland and coastal waters.
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Affiliation(s)
- Ying Ping Lee
- Department of Civil and Environmental Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1-M1-4, Ookayama, Meguro-ku, Tokyo, 152-8552, Japan
| | - Manabu Fujii
- Department of Civil and Environmental Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1-M1-4, Ookayama, Meguro-ku, Tokyo, 152-8552, Japan.
| | - Tetsuro Kikuchi
- Department of Civil and Environmental Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1-M1-4, Ookayama, Meguro-ku, Tokyo, 152-8552, Japan; Ibaraki Kasumigaura Environmental Science Center, 1853 Okijyuku-machi, Tsuchiura, Ibaraki, 300-0023, Japan
| | - Masafumi Natsuike
- Department of Civil and Environmental Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1-M1-4, Ookayama, Meguro-ku, Tokyo, 152-8552, Japan
| | - Hiroaki Ito
- Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuou, Kumamoto, 860-8555, Japan
| | - Toru Watanabe
- Faculty of Agriculture, Yamagata University, 1-23 Wakaba-machi, Tsuruoka, Yamagata, 997-8555, Japan
| | - Chihiro Yoshimura
- Department of Civil and Environmental Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1-M1-4, Ookayama, Meguro-ku, Tokyo, 152-8552, Japan
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2
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Wang K, Garg S, Waite TD. Redox Transformations of Iron in the Presence of Exudate from the Cyanobacterium Microcystis aeruginosa under Conditions Typical of Natural Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:3287-3297. [PMID: 28233985 DOI: 10.1021/acs.est.7b00396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Interaction of the exudate secreted by a toxic strain of the cyanobacterium Microcystis aeruginosa with Fe(II) and Fe(III) was investigated here under both acidic (pH 4) and alkaline (pH 8) conditions. At the concentrations of iron and exudate used, iron was present as dissolved iron (<0.025 μm) at pH 4 but principally as small (<0.45 μm) iron oxyhydroxide particles at pH 8 with only ∼3-27% present in the dissolved form as a result of iron binding by the organic exudate. The formation of strong Fe(III) exudate and relatively weak Fe(II) exudate complexes alters the reduction potential of the Fe(III)-Fe(II) redox couple, facilitating more-rapid oxidation of Fe(II) at pH 4 and 8 than was the case in the absence of exudate. Our results further show that the organic exudate contains Fe(III)-reducing moieties, resulting in the production of measurable concentrations of Fe(II). However, these reducing moieties are short-lived (with a half-life of 1.9 h) and easily oxidized in air-saturated environments. A kinetic model was developed that adequately describes the redox transformation of Fe in the presence of exudate both at pH 4 and pH 8.
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Affiliation(s)
- Kai Wang
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, NSW 2052, Australia
| | - Shikha Garg
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, NSW 2052, Australia
| | - T David Waite
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, NSW 2052, Australia
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Pearson HBC, Comber SDW, Braungardt C, Worsfold PJ. Predicting Copper Speciation in Estuarine Waters-Is Dissolved Organic Carbon a Good Proxy for the Presence of Organic Ligands? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2206-2216. [PMID: 28098987 DOI: 10.1021/acs.est.6b05510] [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
A new generation of speciation-based aquatic environmental quality standards (EQS) for metals have been developed using models to predict the free metal ion concentration, the most ecologically relevant form, to set site-specific values. Some countries such as the U.K. have moved toward this approach by setting a new estuarine and marine water EQS for copper, based on an empirical relationship between copper toxicity to mussels (Mytilus sp.) and ambient dissolved organic carbon (DOC) concentrations. This assumes an inverse relationship between DOC and free copper ion concentration owing to complexation by predominantly organic ligands. At low DOC concentrations, the new EQS is more stringent, but above 162 μM DOC it is higher than the previous value. However, the relationship between DOC and copper speciation is poorly defined in estuarine waters. This research discusses the influence of DOC from different sources on copper speciation in estuaries and concludes that DOC is not necessarily an accurate predictor of copper speciation. Nevertheless, the determination of ligand strength and concentrations by Competitive Ligand Exchange Adsorptive Cathodic Stripping Voltammetry enabled the prediction of the free metal ion concentration within an order of magnitude for estuarine waters by using a readily available metal speciation model (Visual MINTEQ).
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Affiliation(s)
- Holly B C Pearson
- Biogeochemistry Research Centre, University of Plymouth , Plymouth, Devon PL4 8AA, United Kingdom
| | - Sean D W Comber
- Biogeochemistry Research Centre, University of Plymouth , Plymouth, Devon PL4 8AA, United Kingdom
| | - Charlotte Braungardt
- Biogeochemistry Research Centre, University of Plymouth , Plymouth, Devon PL4 8AA, United Kingdom
| | - Paul J Worsfold
- Biogeochemistry Research Centre, University of Plymouth , Plymouth, Devon PL4 8AA, United Kingdom
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Fellous A, Andrade S, Vidal-Ramirez F, Calderón R, Beltran J, Correa JA. Modulatory effect of the exudates released by the brown kelp Lessonia spicata on the toxicity of copper in early developmental stages of ecologically related organisms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:3900-3911. [PMID: 27905044 PMCID: PMC5348571 DOI: 10.1007/s11356-016-8120-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/15/2016] [Indexed: 06/06/2023]
Abstract
Lessonia spicata is a key dominant species along the Pacific coast of South America, providing a habitat for many organisms. However, this role can be affected by abiotic stress, such as metals. To counteract the toxic effect, L. spicata, among other seaweeds, releases exudates that bind metals. In this study, tolerances to copper of organisms related to the kelp forest (spores of Ulva lactuca (Chlorophyceae) and L. spicata (Phaeophyceae) and Zoea I of Taliepus dentatus (Milne-Edwards, Crustacea)) were studied; then, exudates are assessed by their protective effect. Exudates increase the 48-h 50% effective concentration (EC50) of the germination of spores from 8 to 23 μg Cu L-1 for U. lactuca and from 119 to 213 μg Cu L-1 for L. spicata and the survival of the larvae Zoea I 48-h 50% of lethal concentration (LC50) from 144 to 249 μg Cu L-1. Results indicated that exudates had a protective effect. Each species is specifically sensitive to copper. Crab larvae Zoea I were able to support higher doses, and exposure before hatching increased their tolerance.
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Affiliation(s)
- Alexandre Fellous
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Lib. B. O'Higgins 340, Santiago, Chile.
- Université Pierre et Marie Curie (Sorbonne-Universités, Paris VI), 4 Place Jussieu, 75005, Paris, France.
| | - Santiago Andrade
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Lib. B. O'Higgins 340, Santiago, Chile
- Center of Applied Ecology and Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Lib. B. O'Higgins 340, Santiago, Chile
| | - Francisco Vidal-Ramirez
- Estación Costera de Investigaciones Marinas La Cruces, Pontificia Universidad Católica de Chile, Osvaldo Marín 1672, Las Cruces, Comuna El Tabo, Región de Valparaíso, Chile
- School of Biological Sciences and Australian Research Council Centre for Excellence in Coral Reef Studies, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Ricardo Calderón
- Estación Costera de Investigaciones Marinas La Cruces, Pontificia Universidad Católica de Chile, Osvaldo Marín 1672, Las Cruces, Comuna El Tabo, Región de Valparaíso, Chile
| | - Jessica Beltran
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Lib. B. O'Higgins 340, Santiago, Chile
| | - Juan A Correa
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Lib. B. O'Higgins 340, Santiago, Chile
- Center of Applied Ecology and Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Lib. B. O'Higgins 340, Santiago, Chile
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Sordet C, Contreras-Porcia L, Lovazzano C, Goulitquer S, Andrade S, Potin P, Correa JA. Physiological plasticity of Dictyota kunthii (Phaeophyceae) to copper excess. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 150:220-8. [PMID: 24704518 DOI: 10.1016/j.aquatox.2014.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/21/2014] [Accepted: 02/24/2014] [Indexed: 05/09/2023]
Abstract
The brown alga Dictyota kunthii is one of the dominant species in the coastal areas of northern Chile affected by copper enrichment due to accumulated mining wastes. To assess its physiological plasticity in handling copper-mediated oxidative stress, 4-days copper exposure (ca. 100 μg/L) experiments were conducted with individuals from a copper impacted area and compared with the responses of plants from a non-impacted site. Several biochemical parameters were then evaluated and compared between populations. Results showed that individuals from the copper-impacted population normally displayed higher levels of copper content and antioxidant enzymes activity (catalase (CAT), ascorbate peroxidase (AP), dehydroascorbate reductase (DHAR), glutathione peroxidase (GP) and peroxiredoxins (PRX)). After copper exposure, antioxidant enzyme activity increased significantly in plants from the two selected sites. In addition, we found that copper-mediated oxidative stress was associated with a reduction of glutathione reductase (GR) activity. Moreover, metabolic profiling of extracellular metabolites from both populations showed a significant change after plants were exposed to copper excess in comparison with controls, strongly suggesting a copper-induced release of metabolites. The copper-binding capacity of those exudates was determined by anodic stripping voltammetry (ASV) and revealed an increased ligand capacity of the medium with plants exposed to copper excess. Results indicated that D. kunthii, regardless their origin, counteracts copper excess by various mechanisms, including metal accumulation, activation of CAT, AP, DHAR, GP and PRX, and an induced release of Cu binding compounds. Thus, plasticity in copper tolerance in D. kunthii seems constitutive, and the occurrence of a copper-tolerant ecotype seems unlikely.
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Affiliation(s)
- C Sordet
- Pontificia Universidad Católica de Chile, Departamento Ecología, Facultad de Ciencias Biológicas, Santiago, Chile.
| | - L Contreras-Porcia
- Universidad Andres Bello, Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, República 470, Santiago, Chile
| | - C Lovazzano
- Universidad Andres Bello, Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, República 470, Santiago, Chile
| | - S Goulitquer
- Plate-forme MetaboMER, CNRS & UPMC, FR2424, Station Biologique, 29688 Roscoff, France
| | - S Andrade
- Pontificia Universidad Católica de Chile, Departamento Ecología, Facultad de Ciencias Biológicas, Santiago, Chile
| | - P Potin
- Université Pierre et Marie Curie - Paris 6, UMR 7139 CNRS, Marine Plants and Biomolecules, Station Biologique, 29688 Roscoff, France
| | - J A Correa
- Pontificia Universidad Católica de Chile, Departamento Ecología, Facultad de Ciencias Biológicas, Santiago, Chile
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6
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Xu H, Yan Z, Cai H, Yu G, Yang L, Jiang H. Heterogeneity in metal binding by individual fluorescent components in a eutrophic algae-rich lake. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2013; 98:266-272. [PMID: 24075645 DOI: 10.1016/j.ecoenv.2013.09.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 09/06/2013] [Accepted: 09/06/2013] [Indexed: 06/02/2023]
Abstract
Dissolved organic matter (DOM) affects the toxicity, mobility and bioavailability of metals in aquatic environment. In this study, the interactions between two metals of environmental concern [Cu(II) and Fe(III)] with DOM in a euthrophic algae-rich lake (Lake Taihu, China), including dissolved natural organic matter (NOM) and algal extracellular polymeric substance (EPS), were studied using fluorescence excitation-emission matrix (EEM) quenching titration combined with parallel factor (PARAFAC) analysis. Obvious protein-like peaks were detected in algal EPS matrix, while both protein- and humic-like peaks can be found in NOM. PARAFAC analysis identified four fluorescent components, including one humic-, one tryptophan- and two tyrosine-like components, from 114 EEM samples. It was shown that fluorescent tyrosine- (log K(M) > 5.21) and humic-like substances (log K(M) > 4.84) in NOM fraction exhibited higher metal binding capacities than those in EPS matrix, while algal EPS was characterized with a high metal-tryptophan-like substances affinity (log K(M) > 5.08). Moreover, for the eutrophic algae-rich lakes, fluorescent tryptophan- and humic-like substances were responsible for Cu transportation, whereas the mobility of Fe would be related with the tyrosine-like substances. The results facilitate a further insight into the biogeochemical behaviors of metals in eutrophic algae-rich ecosystems as well as other related aquatic environments.
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Affiliation(s)
- Huacheng Xu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China; State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Xianlin Campus, Nanjing University, Nanjing 210023, China
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7
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Karavoltsos S, Sakellari A, Strmečki S, Plavšić M, Ioannou E, Roussis V, Dassenakis M, Scoullos M. Copper complexing properties of exudates and metabolites of macroalgae from the Aegean Sea. CHEMOSPHERE 2013; 91:1590-5. [PMID: 23352148 DOI: 10.1016/j.chemosphere.2012.12.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 05/09/2023]
Abstract
Macroalgae are a significant source of extracellular organic material in the coastal areas of the Mediterranean, including organic ligands which serve as modulators of metal complexing capacity. This paper examines the release of copper-complexing ligands by 24 macroalgal species, including chlorophyta, rhodophyta, ochrophyta as well as Posidonia oceanica, common throughout the Mediterranean. Metabolites isolated from the algae Dictyota dichotoma and Pterocladiella capillacea were examined for the first time regarding their Cu-complexing properties. The concentration of ligands (LT) and the copper-binding strength (logKapp) of exudates and metabolites were determined by electrochemical methods. All algal species released ligands giving LT concentrations ranging from 109 to 744 nM in unfiltered samples. An increase in the concentration of ligands up to 15 times in comparison to the blank was observed after 48 h of culturing macroalgae in artificial seawater. The binding strength (log Kapp) varied among species from 7.0 to 8.6, except for the metabolites for which it was lower (log Kapp=6). Most of the ligands released were in the dissolved phase, with the contribution of particulate and/or colloidal organic matter (up to 46% of total ligands) appearing to be important only in specific macroalgal species.
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Affiliation(s)
- Sotirios Karavoltsos
- National and Kapodistrian University of Athens, Department of Chemistry, Laboratory of Environmental Chemistry, Panepistimiopolis Zografou, 157 71 Athens, Greece.
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8
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McIntyre AM, Guéguen C. Binding interactions of algal-derived dissolved organic matter with metal ions. CHEMOSPHERE 2013; 90:620-626. [PMID: 23022170 DOI: 10.1016/j.chemosphere.2012.08.057] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 08/27/2012] [Accepted: 08/28/2012] [Indexed: 06/01/2023]
Abstract
The nature and composition of dissolved organic matter (DOM) strongly influences its binding properties to heavy metals and thus their fate, mobility and toxicity in aquatic environments. Fluorescence spectroscopy with parallel factor analysis (PARAFAC) was used to characterize DOM exuded by the cosmopolitan freshwater green algae Scenedesmus acutus during early exponential growth phase. One protein-like (peak T; C2) and two humic-like components (peaks A+C and A+M, C1 and C3, respectively) were split half validated on 122 emission-excitation matrices (EEMs). Our data show that both humic-like could be associated with biological activities. Unlike Cd, Pb and Zn, Cu strongly binds to algogenic DOM with conditional stability constants (logK) averaging 5.26±0.29 (from 4.85 to 5.36). Significant differences in logK values were found between humic-like PARAFAC components, indicating clear differences in the binding properties of humic-like components with copper.
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Affiliation(s)
- A M McIntyre
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, Canada K9J 7B8
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9
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Larsen MM, Søndergaard J, Asmund G, Parmentier K, Vermaercke P. Trace Elements. CHEMICAL MARINE MONITORING 2012. [DOI: 10.1002/9781119990826.ch4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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10
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Brown MT, Newman JE, Han T. Inter-population comparisons of copper resistance and accumulation in the red seaweed, Gracilariopsis longissima. ECOTOXICOLOGY (LONDON, ENGLAND) 2012; 21:591-600. [PMID: 22095160 DOI: 10.1007/s10646-011-0819-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/06/2011] [Indexed: 05/31/2023]
Abstract
Copper (Cu) resistance and accumulation of five populations of the red seaweed Gracilariopsis longissima collected from sites in south west England (Fal Estuary, Helford Estuary and Chesil Fleet) that differ in their degree of Cu contamination was assessed under controlled laboratory conditions, on two separate occasions (April and October). The effects of a range of Cu concentrations (0-250 μg l(-1)) on relative growth rates was the same for all populations with reductions observable at concentrations as low as 12 μg l(-1) and cessation of growth at 250 μg l(-1). There was no significant difference in the calculated EC(50) values for the April and October samples, with means of 31.1 and 25.8 μg l(-1), respectively. Over the range of concentrations used in this study, copper content increased linearly and the pattern of accumulation was the same for all populations at both time periods. From the linear regressions of the pooled data a concentration factor of 2.25 × 10(3) was calculated. These results imply that G. longissima has an innate tolerance to Cu and that populations have not evolved copper-tolerant ecotypes. In laboratory studies, accumulated Cu was released when transferred to 'clean' seawater with approximately 80% being lost after 8 days, with no significant difference between populations in their response. The results from a 30 days in situ transplantation experiment using two populations from the Fal Estuary provided further evidence for dynamic changes in Cu content in response to changes in Cu bioavailability. The findings in this study are discussed in the context of implications for seaweed biomonitoring.
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Affiliation(s)
- Murray T Brown
- School of Marine Science and Engineering, Plymouth University, Plymouth, UK.
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11
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Sander SG, Hunter KA, Harms H, Wells M. Numerical approach to speciation and estimation of parameters used in modeling trace metal bioavailability. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:6388-6395. [PMID: 21751821 DOI: 10.1021/es200113v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Speciation affects trace metal bioavailability. One model used to describe the importance of speciation is the biotic ligand model (BLM), wherein the competition of inorganic and organic ligands with a biotic ligand for free-ion trace metal determines the ultimate metal availability to biota. This and similar models require natural ligand concentrations and conditional stability constants as input parameters. In concept, the BLM is itself an analogue of some analytical approaches to the determination of trace metal speciation. A notable example is competitive ligand equilibration/cathodic stripping voltammetry, which employs an artificial ligand for comparative assessment of natural ligand concentrations and discrete conditional stability constants (i.e., BLM parameters) in a natural sample. Here, we report a new numerical approach to voltammetric speciation and parameter estimation that employs multiple analytical windows and a two-step optimization process, simultaneously generating both parameters and a complete suite of corresponding species concentrations. This approach is more powerful, systematic, and flexible than those previously reported.
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Affiliation(s)
- Sylvia G Sander
- Marine and Freshwater Chemistry, Department of Chemistry, University of Otago, Dunedin, New Zealand
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12
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Connan S, Stengel DB. Impacts of ambient salinity and copper on brown algae: 2. Interactive effects on phenolic pool and assessment of metal binding capacity of phlorotannin. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 104:1-13. [PMID: 21543047 DOI: 10.1016/j.aquatox.2011.03.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 03/21/2011] [Accepted: 03/23/2011] [Indexed: 05/30/2023]
Abstract
The aim of this study was to establish in laboratory experiments a quantitative link between phenolic pool (production, composition and exudation) in Ascophyllum nodosum and Fucus vesiculosus and their potential to bind metals. Additionally, the copper binding capacity of purified phlorotannin was investigated. A reduction in salinity decreased total phenolic contents, altered phenolic composition by increasing proportion of cell-wall phenolics, and also increased phenolic exudation of the two seaweed species. After 15 days at a salinity of 5, the inhibition of photosynthesis observed previously for A. nodosum coincided with the high exudation of phenolic compounds into the surrounding water of the seaweed tips which resulted in a significant reduction of phenolic contents. Increased copper concentration also reduced total phenolic contents, changed phenolic composition (increase in proportion and level of cell-wall phenolics), and positively affected phenolic exudation of A. nodosum and F. vesiculosus. A decrease in salinity enhanced the copper toxicity and caused the earlier impact on the physiology of seaweed tips. An involvement of phlorotannins in copper binding is also demonstrated; purified phlorotannins from A. nodosum collected from a site with little anthropogenic activity contained all four metals tested. When placed in copper-enriched water, as for the seaweed material, copper contents of the phenolics increased, zinc and cadmium contents decreased, but no change in chromium content was observed. The use of cell-wall phenolic content as biomarker of copper contamination seems promising but needs further investigation.
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Affiliation(s)
- Solène Connan
- Botany and Plant Science, School of Natural Sciences, Environmental Change Institute and Martin Ryan Institute, National University of Ireland Galway, Galway, Ireland.
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13
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Boschi C, Maldonado H, Ly M, Guibal E. Cd(II) biosorption using Lessonia kelps. J Colloid Interface Sci 2011; 357:487-96. [PMID: 21376338 DOI: 10.1016/j.jcis.2011.01.108] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 01/28/2011] [Accepted: 01/31/2011] [Indexed: 11/18/2022]
Abstract
Lessonia kelps (L. trabeculata and L. nigrescens) have been successfully used for the recovery of Cd(II) from near neutral solutions. The biomass was pre-treated with calcium chloride for stabilization of alginate-based compounds. SEM-EDAX analysis and FT-IR spectrometry analysis were used for identifying the modifications of the biomass. Sorption isotherms were performed at the optimum pH (i.e., pH 6) and the maximum sorption capacity reached up to 1 and 1.5 mmol Cd g(-1) for L. nigrescens (L.n.) and L. trabeculata (L.t.), respectively. The Langmuir equation fits well experimental data. The temperature (in the range 20-40 °C) had a more marked effect on affinity coefficient than on maximum sorption capacity. The influence of particle size, sorbent dosage, metal concentration and temperature was evaluated on uptake kinetics. The kinetic profiles that were modeled using the Crank equation (i.e., the resistance to intraparticle diffusion) were hardly affected by the temperature and the particle size contrary to the sorbent dosage and the metal concentration, which show greater impact. The pseudo-second order rate equation was also tested for the modeling of uptake kinetics.
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Affiliation(s)
- Carmen Boschi
- Ecole des Mines d'Alès, Laboratoire Génie de l'Environnement Industriel, Equipe BPCI, 6 avenue de Clavières, F-30319 ALES cedex, France
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14
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Hengst MB, Andrade S, González B, Correa JA. Changes in epiphytic bacterial communities of intertidal seaweeds modulated by host, temporality, and copper enrichment. MICROBIAL ECOLOGY 2010; 60:282-290. [PMID: 20333374 DOI: 10.1007/s00248-010-9647-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 02/17/2010] [Indexed: 05/29/2023]
Abstract
This study reports on the factors involved in regulating the composition and structure of bacterial communities epiphytic on intertidal macroalgae, exploring their temporal variability and the role of copper pollution. Culture-independent, molecular approaches were chosen for this purpose and three host species were used as models: the ephemeral Ulva spp. (Chlorophyceae) and Scytosiphon lomentaria (Phaeophyceae) and the long-living Lessonia nigrescens (Phaeophyceae). The algae were collected from two coastal areas in Northern Chile, where the main contrast was the concentration of copper in the seawater column resulting from copper-mine waste disposals. We found a clear and strong effect in the structure of the bacterial communities associated with the algal species serving as host. The structure of the bacterial communities also varied through time. The effect of copper on the structure of the epiphytic bacterial communities was significant in Ulva spp., but not on L. nigrescens. The use of 16S rRNA gene library analysis to compare bacterial communities in Ulva revealed that they were composed of five phyla and six classes, with approximately 35 bacterial species, dominated by members of Bacteroidetes (Cytophaga-Flavobacteria-Bacteroides) and α-Proteobacteria, in both non-polluted and polluted sites. Less common groups, such as the Verrucomicrobiae, were exclusively found in polluted sites. This work shows that the structure of bacterial communities epiphytic on macroalgae is hierarchically determined by algal species > temporal changes > copper levels.
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Affiliation(s)
- Martha B Hengst
- Departamento de Acuicultura, Antofagasta Institute of Renewable Resources, Universidad de Antofagasta, Campus Coloso, Antofagasta, Chile
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