Copper Dynamics and the Mechanism of Ecosystem Level Recovery in a Standardized Aquatic Microcosm

Meador, James P.; Taub, Frieda B.; Sibley, Thomas H.

doi:10.2307/1941797

Cited by 30 publications

(26 citation statements)

References 53 publications

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“…This fact renders the present results compatible with the conclusions of other authors (e.g. Sunda & Guillard, 1976;Anderson & Morel, 1978;Verweij et al, 1992;Meador et al, 1993) that copper toxicity is a direct function of free copper. Similarly, the conclusion of Morel (1983) that ionic copper activity provides a measure of the reactivity of the metal in solution, is not inconsistent with the present results.…”

Section: Biological Effectssupporting

confidence: 94%

“…Although copper toxicity to algae is still considered by some authors to be dependent only on the concentration of the free metal (e.g. Menkissoglu & Lindow, 1991;Morgan & Stumm, 1991;Verweij et al, 1992;Meador et al, 1993), others have pointed out the importance of complexed copper (the labile species) on copper toxicity (e.g. Price et al, I989;Sunda, 1989;Buckley, 1994;Tubbing eta]., 1994).…”

Section: Introductionmentioning

confidence: 99%

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Toxicity effects of copper (II) on the marine dinoflagellateAmphidinium carterae: Influence of metal speciation

Lage

Soares

Vasconcelos

et al. 1996

European Journal of Phycology

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The influence of copper(II) concentration and speciation on the growth of Amphidinium carterae in batch culture in a modified ESAW medium was evaluated by two different experimental designs: (i) copper(If) was added to the cultures 2 h after cell inoculation and (ii) copper( II ) had a 24 h pre-equilibration period in the medium before cell inoculation. To complement the biological data, the following information on the chemical/biological system was obtained: (a) computational speciation of the culture medium under chemical equilibrium conditions: (b) total and electrochemically labile copper concentrations in the culture medium during the toxicity experiments; and (c) cellular levels of copper. The labile fraction of copper was measured by potentiometric stripping analysis (PSA) at a deposition potential (Ed) of --0"3 V. At this E d the dissociation of Cu-EDTA complexes was negligible. In both kinds of experiments the effects of copper were more evident after 4 days than after 7 or 10 days of exposure. When compared with situation (ii) pronounced toxic effects were observed under situation (i): (1) A. carterae growth rate was affected at lower copper concentration and in a more acute way: (2) the cells were exposed to significantly higher levels of labile copper (2-to 3-fold more than in situation (ii) for 13"4 #M total copper) and (3) after 2 h of exposure to the metal the copper sorbed by the cells was about 2-fold higher. These results provide evidence for the importance of kinetic parameters in toxicity studies. Experimental copper lability together with speciation calculations provided additional evidence that the bioavailable copper and its cellular toxicity are directly related to the labile metal concentration. This is higher than but directly proportional to the initial free metal concentration in the medium, as was experimentally verified. PSA-derived copper lability provided a reasonable indicator of metal bioavailability to A. carterae in this synthetic seawater medium. A first response of A. carterae to copper toxicity is the release of the metal due to re-equilibration between copper bound to the cell surface and to the ligands in the medium and/or efflux. A different mechanism must subsequently be activated, allowing growth despite the relatively high cellular levels of copper observed.

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Section: Biological Effectssupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Toxicity effects of copper (II) on the marine dinoflagellateAmphidinium carterae: Influence of metal speciation

Lage

Soares

Vasconcelos

et al. 1996

European Journal of Phycology

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“…Per treatment, six microcosms were used, and six additional microcosms served as a control, resulting in 24 microcosms in total. In the treated enclosures, Cu sulfate was added after 7 d, and the densities of the 17 taxa were monitored on 18 sampling occasions (days 4,7,11,14,18,21,25,28,32,35,39,42,46,49,53,56,60, and 63). Abundances were converted to carbon (mg C L À1 ) for subsequent carbon budget calculation (see below under Carbon budget calculation) using organism dimensions that were measured during the microcosm experiment and volume to carbon ratios (Supplemental Data, Tables S1 and S2).…”

Section: Microcosm Experimentsmentioning

confidence: 99%

“…Carbon budgets were initially calculated for all 24 microcosms at 15 different points in time (days 11,14,18,21,25,28,32,35,39,42,46,49,53,56,60), following an earlier methodology [17] by constructing 360 (24 Â 15) linear inverse models (LIMs). Linear inverse modeling allows one mathematically to combine prior knowledge on a set of physiological constraints with site-specific food web topology, taxa densities, and rates of change of these densities to estimate carbon flows between ecosystem components [21,22].…”

Section: Carbon Budget Calculationmentioning

confidence: 99%

Ecosystem functions and densities of contributing functional groups respond in a different way to chemical stress

Laender

Taub

Janssen

2011

Enviro Toxic and Chemistry

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Understanding whether and to what extent ecosystem functions respond to chemicals is a major challenge in environmental toxicology. The available data gathered by ecosystem-level experiments (micro- and mesocosms) often describe the responses of taxa densities to stress. However, whether these responses are proportional to the responses of associated ecosystem functions to stress is unclear. By combining a carbon budget modeling technique with data from a standardized microcosm experiment with a known community composition, we quantified three ecosystem functions (net primary production [NPP], net mesozooplankton production [NZP], and net bacterial production [NBP]) at three Cu concentrations, with a control. Changes of these ecosystem functions with increasing chemical concentrations were not always proportional to the Cu effects on the densities of the contributing functional groups. For example, Cu treatments decreased mesozooplankton density by 100-fold and increased phytoplankton density 10- to 100-fold while increasing NZP and leaving NPP unaltered. However, in contrast, Cu affected microzooplankton and the associated function (NBP) in a comparable way. We illustrate that differences in the response of phytoplankton/mesozooplankton densities and the associated ecosystem functions to stress occur because functional rates (e.g., photosynthesis rates/ingestion rates) vary among Cu treatments and in time. These variations could be explained by food web ecology but not by direct Cu effects, indicating that ecology may be a useful basis for understanding environmental effects of stressors.

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“…The use of microcosms in pollution studies has been tried in a number of environments, including wetlands (Johnson, 1986), salt-marshes (O'Neill, Cripe, Mueller, Connolly & Prichard, 1989, soils (Van Beelen, Fleuren-Kemila, Huys, van Montfort & van Vlaardingen, 1991), freshwaters (Meador, Taub, & Sibley, 1992), estuaries (Lauth, Scott, Cherry & Buikema, 1996), and the deep-sea (Gross, 2000). Chapman & Long (1983) pointed out the need for relevant bioassays as part of a broad-based approach in determining the impact of pollutants in the marine sedimentary environment.…”

Section: Introductionmentioning

confidence: 99%

An assessment of the impact of copper mine tailings disposal on meiofaunal assemblages using microcosm bioassays

Lee

Correa

2007

Marine Environmental Research

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Microcosms were used to assess the impact of copper mine tailings disposal on the littoral meiofaunal assemblages of the Atacama region of northern Chile. The specific purpose was to establish a cause and effect relationship between the elevated copper concentrations and altered meiofaunal assemblages observed at the study sites. Meiofaunal assemblages were exposed to a series of copper concentrations to assess general toxicity, both densities and taxa diversities decreased with increasing copper. Natural coarse sediments were mixed with a tailings substitute to assess the physical impact of the tailings dumping on meiofaunal assemblages. Meiofaunal assemblage densities increased with increasing amounts of tailings substitute, entirely due to an increase in surface utilising foraminiferans. However, taxa diversities decreased as the interstitial spaces became blocked. Finally, the microcosms were used to conduct bioassays of sediments and seawaters from the impacted sites. The sediments from the impacted sites proved to be toxic resulting in reduced meiofau- Preprint submitted to Elsevier Science 1 November 2006ACCEPTED MANUSCRIPT nal densities and taxa diversities. Seawater samples did not prove to be significantly toxic. The use of microcosms has allowed the effects of the physical and chemical components of tailings to be assessed individually, which was not possible in the field. Additionally, it allowed a cause and effect relationship to be established between elevated concentrations of porewater copper observed in the field and the reduced densities and taxa diversities of the meiofaunal assemblages observed at the same sites.

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Copper Dynamics and the Mechanism of Ecosystem Level Recovery in a Standardized Aquatic Microcosm

Cited by 30 publications

References 53 publications

Toxicity effects of copper (II) on the marine dinoflagellateAmphidinium carterae: Influence of metal speciation

Toxicity effects of copper (II) on the marine dinoflagellateAmphidinium carterae: Influence of metal speciation

Ecosystem functions and densities of contributing functional groups respond in a different way to chemical stress

An assessment of the impact of copper mine tailings disposal on meiofaunal assemblages using microcosm bioassays

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