Cyanobacterial blooms in the Baltic Sea: Natural or human‐induced?

Bianchi, Thomas S.; Engelhaupt, Erika; Westman, Per; Andrén, Thomas; Rolff, Carl; Elmgren, Ragnar

doi:10.4319/lo.2000.45.3.0716

Cited by 317 publications

(228 citation statements)

References 36 publications

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“…20,21 Considering cyanobacterial blooms and As pollution coexist in many freshwater lakes in China, 12 it is important to understand the effect of P on As transformations in cyanobacteria and therefore facilitate the application of cyanobacteria in As remediation. In this study, we chose the typical freshwater cyanobacteria Synechocystis sp.…”

Section: ■ Introductionmentioning

confidence: 99%

Cyanobacteria-Mediated Arsenic Redox Dynamics Is Regulated by Phosphate in Aquatic Environments

Zhang

Rensing

Zhu

2013

Environ. Sci. Technol.

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Studies of cyanobacteria in environments where arsenic (As) and phosphate (P) both occur in significant concentrations have so far only focused on the effect of P on As(V) toxicity and bioaccumulation, with little attention to the influence of P on As redox transformations. Our study revealed that As(III) oxidation by Synechocystis appeared to be more effective with increased P levels. We demonstrated that the higher As(III) percentage in the medium under P-limited conditions was due to enhanced As(V) uptake and the subsequent efflux of intracellularly reduced As(III) which in turn contributed to higher As(III) concentrations in the medium. Arsenic redox changes by Synechocystis under P-limited conditions is a dynamic cyclic process that includes the following: surface As(III) oxidation (either in the periplasm or near the outer membrane), As(V) uptake, intracellular As(V) reduction, and As(III) efflux. These observations not only expand our understanding of how P influences microbial As redox metabolisms but also provide insights into the biogeochemical coupling between As and P in As contaminated eutrophic aquatic environments and artificial wetland-paddy fields. ■ INTRODUCTIONArsenic (As) is a ubiquitous toxic substance broadly distributed in the environment. 1 The transport and transformation of As in environment are governed by geochemical and biological processes, generating an As biogeochemical cycle. 2 Microbially mediated biotransformations may play an important role in determining As biogeochemistry and toxicity in various natural ecosystems, especially As redox processes which influence the two most abundant inorganic As forms (arsenite As(III) and arsenate As(V)) in the environment. 3 Thus it is essential to understand microbial As redox metabolisms to make further advances in As bioremediation.Microalgae are desirable organisms for As remediation in contaminated water because of their high surface area to volume ratios. 4 Studies have shown that microalgae can tolerate high levels of As and biotransform it in several ways to detoxify it. 5−9 Considering the complex living environments of microalgae, many factors could affect As biotransformations by microalgae. Phosphate (P) is one of the most significant determinants of microalgal growth. Due to its structural similarity with As(V), 10 the influence of P on microbial As metabolisms has been extensively studied and primarily focused on As(V) accumulation and toxicity. 11,12 Besides affecting As(V) uptake, P can further influence the subsequent As detoxification process, i.e. As(V) reduction. 13,14 In the bacteria Agrobacterium tumefaciens str. 5B, it has been reported that As(V) reduction was completely suppressed at elevated levels of P (500 and 1000 μM), but the expression of the As(V) reductase gene (arsC) was not inhibited by high P concentrations. 15 As(III) oxidation and the Phosphorus (Pi) concentration were reported to be tightly and intimately coregulated in the soil bacterium Agrobacterium tumefaciens. 16 However, when analyzing ...

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Section: ■ Introductionmentioning

confidence: 99%

Cyanobacteria-Mediated Arsenic Redox Dynamics Is Regulated by Phosphate in Aquatic Environments

Zhang

Rensing

Zhu

2013

Environ. Sci. Technol.

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“…In marine palaeoecology, sedimentary records of both phytoplankton pigments (e.g. Bianchi et al 2000Bianchi et al , 2002 and diatoms (e.g. Cooper 1995;Hay et al 2003) have been used to characterise historical productivity and algal communities.…”

Section: Introductionmentioning

confidence: 99%

Spatial distribution of diatom and pigment sedimentary records in surface sediments in Doubtful Sound, Fiordland, New Zealand

Schüller

Savage

2011

New Zealand Journal of Marine and Freshwater Research

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Algal remains (pigment concentrations, diatom frustules) and organic matter sources (d 15 N, d13 C) in surface sediments (0Á2 cm) were quantified and related to environmental gradients in Doubtful Sound, Fiordland, New Zealand. Sedimentary pigment concentrations, in particular diatoxanthin and fucoxanthin (diatom biomarkers) were elevated near Malaspina Reach, which experiences greater incident irradiance and mixing of silica-rich freshwater with nutrient-rich marine water. In contrast, diatom frustules were recovered in low concentrations in deep basins including Malaspina Reach, most likely related to dissolution and grazing. Spatial variability in pigments in Doubtful Sound was mainly correlated with light conditions (incident irradiance, chromophoric dissolved organic matter). By contrast, diatoms were principally correlated with salinity gradients (effective freshwater depth) and water column stratification (mixing). This study highlights the importance of using complementary sedimentary proxies when reconstructing algal abundance and community composition in fjord environments.

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“…2), in particular during hypoxic bottom water conditions (Bianchi et al 2000). Observations suggest an increase in cyanobacteria after the 1960s (Finni et al 2001).…”

Section: Past Changesmentioning

confidence: 99%

Environmental Impacts—Marine Biogeochemistry

Schneider

Eilola

Lukkari

et al. 2015

Regional Climate Studies

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Marine biogeochemistry deals with the budgets and transformations of biogeochemically reactive elements such as carbon, nitrogen and phosphorus. Inorganic nitrogen and phosphorus compounds are the major nutrients and control organic matter (biomass) production in the surface water. Due to various anthropogenic activities, the input of these nutrients into the Baltic Sea has increased drastically during the last century and has enhanced the net organic matter production by a factor of 2-4 (eutrophication). This has led to detrimental oxygen depletion and hydrogen sulphide production in the deep basins of the Baltic Sea. Model simulations based on the Baltic Sea Action Plan (BSAP) indicate that current eutrophication and thus extension of oxygen-depleted areas cannot be reversed within the next hundred years by the proposed nutrient reduction measures. Another environmental problem is related to decreasing pH (acidification) that is caused by dissolution of the rising atmospheric CO 2 . Estimates indicate a decrease in pH by about 0.15 during the last 1-2 centuries, and continuation of this trend may have serious ecological consequences. However, the concurrent increase in the alkalinity of the Baltic Sea may have significantly counteracted acidification.

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Cyanobacterial blooms in the Baltic Sea: Natural or human‐induced?

Cited by 317 publications

References 36 publications

Cyanobacteria-Mediated Arsenic Redox Dynamics Is Regulated by Phosphate in Aquatic Environments

Cyanobacteria-Mediated Arsenic Redox Dynamics Is Regulated by Phosphate in Aquatic Environments

Spatial distribution of diatom and pigment sedimentary records in surface sediments in Doubtful Sound, Fiordland, New Zealand

Environmental Impacts—Marine Biogeochemistry

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