Influence of the nature of the exudates released by different marine algae on the growth, trace metal uptake and exudation of Emiliania huxleyi in natural seawater

Vasconcelos, M. Teresa S. D.; Leal, Fernanda; Berg, Constant M.G. van den

doi:10.1016/s0304-4203(01)00087-1

Cited by 92 publications

(85 citation statements)

References 41 publications

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“…Leal et al (1999) found that toxic effects to E. huxleyi occurred at [Cu 2ϩ ] levels Ͼ0.025 nmol L Ϫ1 , essentially the same value as observed throughout phase 2 of our mesocosm study (Table 4). The ligand that was produced in our study, however, had a different Cu-complexing strength (log K ϭ 9.9-10.5) to that of the class 2 Ј 2 ligand observed in single culture experiments (Leal et al 1999;Vasconcelos et al 2002). This difference might be explained by differences in the physiological status of the coccolithophore cells between lab cultures and mesocosms or by a different biological source (e.g., prokaryotes or grazers) in the mesocosm study.…”

Section: Discussionmentioning

confidence: 55%

Biological factors regulating the chemical speciation of Cu, Zn, and Mn under different nutrient regimes in a marine mesocosm experiment

Muller

Jacquet

Wilson

2003

Limnology & Oceanography

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Previous mesocosm experiments and field studies have indicated a central role of major nutrients (e.g., N, P, and Si) in regulating phytoplankton abundance and species composition and influencing the rate of uptake of bioactive metals by phytoplankton. We monitored the changes in bioactive metals (Cu, Zn, and Mn) concentration and speciation that occurred over the course of a bloom of the coccolithophore Emiliana huxleyi under three different nutrient treatments. In each treatment, the electrochemically labile fraction of Cu decreased from 1.1 to 0.3 nmol L Ϫ1 during the formation of the E. huxleyi bloom. This decrease was likely due to the active release of organic ligands by phytoplankton, which shut off as soon as the level of labile). Organic Zn-binding ligands showed elevated concentrations in bag 1 (the N-and P-replete bag) only. The release of these ligands coincided with a 15-fold increase in the concentration of dead E. huxleyi cells in bag 1 but only a threefold increase in the P-or N-depleted bags. This suggests that the Zn-binding ligands may have originated from dead or decaying E. huxleyi cells. In both the P-and N-limited bags, labile Mn concentrations showed a succession of two peaks and troughs over the 2-week period; these were synchronized-but inversely correlated-with bacterial abundance. Labile Mn showed weaker fluctuations and no clear synchronization with bacterial abundance in the N-and P-replete bag. We hypothesize that the passive release of organic Zn-binding ligands under the nutrient-replete conditions may have helped restrict the detrimental effect of Zn 2ϩ on Mn uptake by phytoplankton cells, thus diverting part of the dissolved Mn away from sequestration or oxidation by bacteria.It is well established that the growth rate of phytoplankton in the sea is mainly limited by the rate of supply of limiting nutrients-typically N, P, and Si (Cloern 1996). In addition, phytoplankton species composition is strongly influenced by the relative concentrations of these nutrient elements. For example, it is possible to give rise to the selective development of different phytoplankton groups during mesocosm experiments by simply manipulating the nutrient concentrations (Egge and Aksnes 1992;Sterner and Hessen 1994). In turn, the balance struck among different phytoplankton AcknowledgmentsWe are grateful to Clelia Booman and Monica Martinussen (Department of Fisheries and Marine Biology, University of Bergen) for organizing a very successful workshop in which all participants involved in the mesocosm study were able to discuss their results and exchange useful data and information. We also thank our two anonymous reviewers for their constructive criticisms and the associate editor, Mary Scranton, for her many good suggestions.

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Section: Discussionmentioning

confidence: 55%

Biological factors regulating the chemical speciation of Cu, Zn, and Mn under different nutrient regimes in a marine mesocosm experiment

Muller

Jacquet

Wilson

2003

Limnology & Oceanography

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“…Two hundred fifty milliliters was removed for analysis each day for the 8 d and therefore the surface area available for adsorption decreased to half (2 liters) during the incubation period. Vasconelos et al (2002) measured metal concentrations in algae (extracellular adsorption plus intracellular uptake) and found that the metal concentration in the algae balanced the metal lost from seawater, thus indicating negligible adsorption onto container walls. Therefore, given the minimal removal of trace metals to the walls of containers, the loss of metal from the dissolved phase in the four treatments can be assumed to be predominately through extracellular adsorption onto and uptake into the cells.…”

Section: Resultsmentioning

confidence: 99%

Iron and zinc enrichments in the northeastern subarctic Pacific: Ligand production and zinc availability in response to phytoplankton growth

et al. 2005

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Iron-and zinc-enrichment experiments were carried out at Ocean Station Papa in the subarctic North Pacific. In iron-enriched treatments, phytoplankton chlorophyll a (Chl a) increased 20-fold (9.7 g L Ϫ1 ) above the concentration on day zero. No stimulation of Chl a production or nitrate drawdown was observed on addition of zinc alone compared to the control. In the iron-enriched treatment, bioavailable zinc concentration decreased to 0.2 pmol L Ϫ1 lower than that which is known in culture experiments to limit some phytoplankton growth. Theoretical analyses suggest that this zinc concentration would cause diffusion-limited growth of large diatom cells present at the end of the incubation. Direct measurements of zinc-binding ligands indicate that the natural microbial planktonic assemblages have the ability to respond rapidly to conditions of high dissolved zinc concentrations. Rapid ligand production may be a mechanism by which certain phytoplankton reduce zinc toxicity or for maintaining zinc concentrations in the upper water column. Zinc-binding ligands were observed to be both produced and removed on the timescale of 1 d. We suggest that these zinc-binding ligands are produced to assist assimilation, particularly under iron-enriched conditions when concentrations of bioavailable zinc were extremely low, thereby alleviating the effects of zinc limitation.

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“…The beneficial effects of the non-lytic Alexandrium supernatant on Chaetoceros spp. may be explained by metal complexing properties of extracellular organic material, derived from phytoplankton, which can affect trace metal availability as well as seawater toxicity (Croot et al, 2000;Vasconcelos et al, 2002;Rijkenberg et al, 2008). In a laboratory study, growth of the diatom Phaeodactylum tricornutum was enhanced by algal exudates of different macro-and microalgae.…”

Section: Discussionmentioning

confidence: 99%

Allelopathic potential of the dinoflagellate Alexandrium tamarense on marine microbial communities

2010

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Influence of the nature of the exudates released by different marine algae on the growth, trace metal uptake and exudation of Emiliania huxleyi in natural seawater

Cited by 92 publications

References 41 publications

Biological factors regulating the chemical speciation of Cu, Zn, and Mn under different nutrient regimes in a marine mesocosm experiment

Biological factors regulating the chemical speciation of Cu, Zn, and Mn under different nutrient regimes in a marine mesocosm experiment

Iron and zinc enrichments in the northeastern subarctic Pacific: Ligand production and zinc availability in response to phytoplankton growth

Allelopathic potential of the dinoflagellate Alexandrium tamarense on marine microbial communities

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