Occurrence and chemical form of arsenic in marine macroalgae from the east coast of Australia

2002 ◽  
Vol 53 (6) ◽  
pp. 971 ◽  
Author(s):  
R. Tukai ◽  
W. A. Maher ◽  
I. J. McNaught ◽  
M. J. Ellwood ◽  
M. Coleman

Arsenic concentrations were measured in thirteen macroalgal species from Sydney, Australia. Brown macroalgae contained, on average, more arsenic (range, mean ± s.e.: 5–173 μg g–1, 39 ± 4 μg g–1) than either green (0.12–30.2 μg g–1, 10.7 ± 0.7 μg g–1) or red macroalgae (0.11–16.9 μg g–1, 4.3 ± 0.3 μg g–1). Despite the overlap in arsenic concentrations between different macroalgal species, inter-species arsenic variation was apparent with arsenic concentrations following the order brown > green > red macroalgal species. It was concluded that the main contribution to the variation in arsenic concentration was from natural variability expected to occur between individuals of any species as a result of physiological differences.Most of the arsenic compounds in macroalgae (70–108%) could be extracted using methanol/water mixtures, with 38–95% of the arsenic compounds present in characterizable forms. All macroalgal species contained arsenoribosides (9–99%). The distribution of arsenoribosides followed a general pattern; glycerol-arsenoriboside and phosphate-arsenoriboside were common to all macroalgal species. Sulfonate-arsenoriboside and sulfate-arsenoriboside were found in brown macroalgal species and one red macroalgal species. Six macroalgal species contained high concentrations of inorganic arsenic (14.2–62.9%) and four species contained high concentrations of dimethylarsinic acid (13.3–41.1%). The variation in the distribution of arsenic compounds in marine macroalgal species appears to be related to taxonomic differences in storage and structural polysaccharides.

2016 ◽  
Vol 13 (4) ◽  
pp. 577 ◽  
Author(s):  
Shin-ichi Miyashita ◽  
Chisato Murota ◽  
Keisuke Kondo ◽  
Shoko Fujiwara ◽  
Mikio Tsuzuki

Environmental context Cyanobacteria are ecologically important, photosynthetic organisms that are widely distributed throughout the environment. They play a central role in arsenic transformations in terms of both mineralisation and formation of organoarsenic species as the primary producers in aquatic ecosystems. In this review, arsenic resistance, transport and biotransformation in cyanobacteria are reviewed and compared with those in other organisms. Abstract Arsenic is a toxic element that is widely distributed in the lithosphere, hydrosphere and biosphere. Some species of cyanobacteria can grow in high concentrations of arsenate (pentavalent inorganic arsenic compound) (100mM) and in low-millimolar concentrations of arsenite (trivalent inorganic arsenic compound). Arsenate, which is a molecular analogue of phosphate, is taken up by cells through phosphate transporters, and inhibits oxidative phosphorylation and photophosphorylation. Arsenite, which enters the cell through a concentration gradient, shows higher toxicity than arsenate by binding to sulfhydryl groups and impairing the functions of many proteins. Detoxification mechanisms for arsenic in cyanobacterial cells include efflux of intracellular inorganic arsenic compounds, and biosynthesis of methylarsonic acid and dimethylarsinic acid through methylation of intracellular inorganic arsenic compounds. In some cyanobacteria, ars genes coding for an arsenate reductase (arsC), a membrane-bound protein involved in arsenic efflux (arsB) and an arsenite S-adenosylmethionine methyltransferase (arsM) have been found. Furthermore, cyanobacteria can produce more complex arsenic species such as arsenosugars. In this review, arsenic metabolism in cyanobacteria is reviewed, compared with that in other organisms. Knowledge gaps remain regarding both arsenic transport (e.g. uptake of methylated arsenicals and excretion of arsenate) and biotransformation (especially production of lipid-soluble arsenicals). Further studies in these areas are required, not only for a better understanding of the role of cyanobacteria in the circulation of arsenic in aquatic environments, but also for their application to arsenic bioremediation.


Encyclopedia ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 177-188
Author(s):  
Leonel Pereira

What are algae? Algae are organisms that perform photosynthesis; that is, they absorb carbon dioxide and release oxygen (therefore they have chlorophyll, a group of green pigments used by photosynthetic organisms that convert sunlight into energy via photosynthesis) and live in water or in humid places. Algae have great variability and are divided into microalgae, small in size and only visible through a microscope, and macroalgae, which are larger in size, up to more than 50 m (the maximum recorded was 65 m), and have a greater diversity in the oceans. Thus, the term “algae” is commonly used to refer to “marine macroalgae or seaweeds”. It is estimated that 1800 different brown macroalgae, 6200 red macroalgae, and 1800 green macroalgae are found in the marine environment. Although the red algae are more diverse, the brown ones are the largest.


2005 ◽  
Vol 2 (2) ◽  
pp. 108 ◽  
Author(s):  
Joel Waring ◽  
William Maher ◽  
Simon Foster ◽  
Frank Krikowa

Environmental Context. In well-oxygenated water and sediments, nearly all arsenic is present as arsenate (AsO43−). As arsenate is a phosphate (PO43−) analogue, organisms living in arsenate-rich environments must acquire the nutrient phosphorus yet avoid arsenic toxicity. Organisms take in and transform arsenic compounds by many means. Three major modes of arsenic biotransformation have been found to occur in the environment—redox transformation between arsenate and arsenite (AsO2−), the reduction and methylation of arsenic, and the biosynthesis of organoarsenic compounds such as arsenobetaine. These biotransformations lead to biogeochemical cycling of arsenic compounds and bioconcentration of arsenic in aquatic organisms and thence into the food web. Abstract. The paper reports the whole-tissue total arsenic concentrations and water-soluble arsenic species in eight common coastal Australian polychaete species. Laboratory experiments showed the period of depuration did not significantly alter the whole-tissue total arsenic concentrations in the two estuarine polychaete species tested. Significant differences were found between the whole-tissue total arsenic concentrations of the eight polychaete species (mean arsenic concentrations ranged from 18 to 101 µg g−1 dry mass). Total arsenic concentrations in polychaete species, grouped on the basis of a combination of their feeding guild and habitat type, were also significantly different with a significant interaction between these factors indicating that both factors simultaneously influence arsenic concentration in polychaetes. A large number of polychaete species contained similar arsenic species with high proportions of arsenobetaine (AB; 57–88%) and relatively low proportions of As3+, As5+, methyarsonic acid, dimethylarsinic acid, arsenocholine, trimethylarsoniopropionate, and tetramethylarsonium ion (not detected to 12%). All polychaete species contained arsenoribosides (5–30%). This study identified two Australian polychaete species with particularly unusual whole-tissue water-soluble arsenic species proportions: Australonuphis parateres contained a very high proportion of trimethylarsoniopropionate (~33%), while Notomastus estuarius had a very low proportion of arsenobetaine (9%) and high proportions of As3+ (~30%), As5+ (~8%), arsenoribosides (30%), and an unknown anionic arsenic species (~4%). Most polychaetes accumulate arsenobetaine, except deposit feeders inhabiting estuarine mud habitats. Thus most polychaetes, which are prey for higher organisms, are a source of arsenobetaine in benthic food webs. Deposit feeders inhabiting estuarine muddy substrates contain appreciable quantities of inorganic arsenic and arsenoribosides that may be metabolized to different end products in higher organisms.


Biologia ◽  
2006 ◽  
Vol 61 (1) ◽  
Author(s):  
Pavel Tlustoš ◽  
Jiřina Száková ◽  
Daniela Pavlíková ◽  
Jiří Balík

AbstractTomato plants were cultivated in greenhouse and water solutions of arsenite (As(III)), arsenate (As(V)), methylarsonic acid (MA) and dimethylarsinic acid (DMA) were applied individually into cultivation substrate at two As levels, 5 and 15 mg kg−1 of the substrate. Comparing the availability of arsenic compounds increased in order arsenite = arsenate < MA < DMA where the arsenic contents in plants decreased during vegetation period. Within a single plant, the highest arsenic concentration was found in roots followed in decreasing order by leaves, stems, and fruits regardless of arsenic compound applied. Arsenic toxicity symptoms reflected in suppressed growth of plants and a lower number and size of fruits were most significant with DMA treatment. However, the highest accumulation of arsenic by plants growing in the soil containing DMA was caused by higher mobility of this compound in the soil due to its lower sorption affinity. Our results confirmed substantial role of transformation processes of arsenic compounds in soil in uptake and accumulation of arsenic by plants.


2006 ◽  
Vol 72 (12) ◽  
pp. 7912-7915 ◽  
Author(s):  
Satoshi Ohkubo ◽  
Hideaki Miyashita ◽  
Akio Murakami ◽  
Haruko Takeyama ◽  
Tohru Tsuchiya ◽  
...  

ABSTRACT A molecular method for detecting the epiphyte community on marine macroalgae was developed by using PCR-denaturing gradient gel electrophoresis. Selective amplification of 16S rRNA gene fragments from either cyanobacteria or algal plastids improved the detection of minor epiphytes. Two phylotypes of Acaryochloris, a chlorophyll d-containing cyanobacterium, were found not only on red macroalgae but also on green and brown macroalgae.


2012 ◽  
Vol 9 (5) ◽  
pp. 474 ◽  
Author(s):  
Shin-ichi Miyashita ◽  
Shoko Fujiwara ◽  
Mikio Tsuzuki ◽  
Toshikazu Kaise

Environmental contextAlthough arsenic is known to accumulate in both marine and freshwater ecosystems, the pathways by which arsenic is accumulated and transferred in freshwater systems are reasonably unknown. This study revealed that freshwater cyanobacteria have the ability to produce arsenosugars from inorganic arsenic compounds. The findings suggest that not only algae, but cyanobacteria, play an important role in the arsenic cycle of aquatic ecosystems. AbstractMetabolic processes of incorporated arsenate in axenic cultures of the freshwater cyanobacteria Synechocystis sp. PCC 6803 and Nostoc (Anabaena) sp. PCC 7120 were examined. Analyses of arsenic compounds in cyanobacterial extracts using a high-performance liquid chromatography–inductively coupled plasma mass spectrometry system showed that both strains have an ability to biotransform arsenate into oxo-arsenosugar-glycerol within 20 min through (1) reduction of incorporated arsenate to arsenite and (2) methylation of produced arsenite to dimethylarsinic acid by methylarsonic acid as a possible intermediate product. In addition, Synechocystis sp. PCC 6803 cells are able to biosynthesise oxo-arsenosugar-phosphate from incorporated arsenate. These findings suggest that arsenosugar formation as well as arsenic methylation in cyanobacteria possibly play a significant role in the global arsenic cycle.


2018 ◽  
Vol 8 (19) ◽  
Author(s):  
Tom Murphy ◽  
Kongkea Phan ◽  
Emmanuel Yumvihoze ◽  
Kim Irvine ◽  
Ken Wilson ◽  
...  

Background. Arsenic bioaccumulation in rice is a global concern affecting food security and public health. Objective. The present study examined arsenic species in rice in Cambodia to characterize health risks with rice consumption and to clarify uncertainties with Codex guidelines. Methods. The present study collected 61 well water samples, 105 rice samples, 70 soil samples, and conducted interviews with 44 families in Preak Russey near the Bassac River and Kandal Province along the Mekong River in Cambodia. Analyses of metals, total arsenic and arsenic species were conducted in laboratories in Canada, Cambodia and Singapore. Results. Unlike in Bangladesh, rice with the highest total arsenic concentrations in Cambodia contains mostly organic arsenic, dimethylarsinic acid (DMA), which is unregulated and much less toxic than inorganic arsenic. The present study found that storing surface runoff in ditches prior to irrigation can significantly reduce the arsenic concentration in rice. It is possible to remove &gt; 95% of arsenic from groundwater prior to irrigation with natural reactions. Conclusions. The provision of high quality drinking water in 2015 to Preak Russey removed about 95% of the dietary inorganic arsenic exposure. The extremes in arsenic toxicity that are still obvious in these farmers should become less common. Rice from the site with the highest documented levels of arsenic in soils and water in Cambodia passes current Codex guidelines for arsenic. Informed Consent. Obtained Competing Interests. The authors declare no competing financial interests.


2021 ◽  
Vol 64 (1) ◽  
pp. 13-18
Author(s):  
Ira Gray ◽  
Lindsay A. Green-Gavrielidis ◽  
Carol Thornber

Abstract Caffeine is present in coastal environments worldwide and there is a need to assess its impact on marine organisms. Here, we exposed two species of ecologically important marine macroalgae (Chondrus crispus and Codium fragile subsp. fragile) to a suite of caffeine concentrations and measured their response. Caffeine concentrations of 10–100 ng L−1 had no significant effect on the growth rate or photosynthetic efficiency of either algae. Extremely high concentrations (100–200 mg L−1), which may occur acutely, produced sublethal effects for both species and mortality in C. fragile subsp. fragile. Our results highlight the need to understand how caffeine impacts marine species.


Marine Drugs ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 204
Author(s):  
Marco Garcia-Vaquero ◽  
Gaurav Rajauria ◽  
Marta Miranda ◽  
Torres Sweeney ◽  
Marta Lopez-Alonso ◽  
...  

The main objective was to determine the chemical, phytochemical, fatty acid and mineral profiles of three commercially relevant brown macroalgae (Laminaria digitata, Laminaria hyperborea and Ascophyllum nodosum) collected each season for two years off the west coast of Ireland. All the chemical, phytochemical, fatty acid and minerals analysed varied significantly depending on the macroalgal species, season and year of collection. Overall, the protein contents of macroalgae were negatively correlated with carbohydrate content. Protein (2–11%) was at its highest during winter and/or spring, decreasing to a minimum during summer and/or autumn. The three macroalgal species analysed in this study had clearly differentiated fatty acid profiles. The concentration of fatty acids was higher in A. nodosum compared with both Laminaria species. The mineral profile of the three macroalgal species was rich in essential metals, particularly Ca, Mg and P, while the levels of I were approximately 9- to 10-fold higher in both Laminaria spp. compared with A. nodosum. The levels of toxic metals (Cd, Hg and Pb) in all the macroalgal species studied were low in the current study; while the levels of total As were high (49–64 mg/kg DW macroalgae) compared with previous reports.


1983 ◽  
Vol 40 (8) ◽  
pp. 1254-1257 ◽  
Author(s):  
M. D. Baker ◽  
P. T. S. Wong ◽  
Y. K. Chau ◽  
C. I. Mayfield ◽  
W. E. Inniss

Isolates from four genera of freshwater green algae were capable of methylating sodium arsenite in lake water and Bold's basal medium. Analysis of the liquid phase of the methylation flasks revealed the presence of methylarsonic acid, dimethylarsinic acid, and trimethylarsine oxide. Volatile arsine and methylarsines were not detected in the headspace gases presumably because of the inability of the algae to reduce completely the methylated–arsenic species. Although the algae varied with respect to their methylating abilities, the levels of methylated–arsenic compounds were always significantly higher when the algae were grown in lake water. This may have been due to the lower phosphate concentration in the lake water. We suggest that arsenic methylation by green algae constitutes an additional source for the formation and cycling of organo-arsenic compounds in freshwater ecosystems.


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