Abstract:In contrast to substantial studies and established knowledge of aluminum (Al) effects 2 (mainly toxicity) on freshwater organisms and terrestrial plants, and even on human 3 health, only a few studies of Al effects on marine organisms have been reported, and our 4 understanding of the role of Al in marine biogeochemistry is limited. In this paper, we 5 the role of Al in the stimulation of phytoplankton growth and carbon sequestration in the 1 ocean depths. 2
“…Thus, effects on growth of marine algae caused by Al seem unlikely. The same conclusion was drawn by Zhou et al, who reviewed the aluminum toxicity to marine phytoplankton [17]. However, Gillmore et al showed that diatoms with higher silicon content in cell walls are more sensitive [33].…”
Section: Discussionsupporting
confidence: 65%
“…In this context, compared to invertebrates, fish have been proven to be particularly sensitive to Al exposition, in neutral to basic water a no effect concentration of 100 µg/l Al was reported for trouts. In contrast, marine studies on the ecotoxicological impact of galvanic anodes are scarce [17]. So far, very little attention has been paid to studying the toxicity and accumulation of Al in benthic organisms.…”
Background
Cathodic protection by sacrificial anodes composed of aluminum-zinc-indium alloys is often applied to protect offshore support structures of wind turbines from corrosion. Given the considerable growth of renewable energies and thus offshore wind farms in Germany over the last decade, increasing levels of aluminum, indium and zinc are released to the marine environment. Although these metals are ecotoxicologically well-studied, data regarding their impact on marine organisms, especially sediment-dwelling species, as well as possible ecotoxicological effects of galvanic anodes are scarce. To investigate possible ecotoxicological effects to the marine environment, the diatom Phaedactylum tricornutum, the bacterium Aliivibrio fischeri and the amphipod Corophium volutator were exposed to dissolved galvanic anodes and solutions of aluminum and zinc, respectively, in standardized laboratory tests using natural seawater. In addition to acute toxicological effects, the uptake of these elements by C. volutator was investigated.
Results
The investigated anode material caused no acute toxicity to the tested bacteria and only weak but significant effects on algal growth. In case of the amphipods, the single elements Al and Zn showed significant effects only at the highest tested concentrations. Moreover, an accumulation of Al and In was observed in the crustacea species.
Conclusions
Overall, the findings of this study indicated no direct environmental impact on the tested marine organisms by the use of galvanic anodes for cathodic protection. However, the accumulation of metals in, e.g., crustaceans might enhance their trophic transfer within the marine food web.
“…Thus, effects on growth of marine algae caused by Al seem unlikely. The same conclusion was drawn by Zhou et al, who reviewed the aluminum toxicity to marine phytoplankton [17]. However, Gillmore et al showed that diatoms with higher silicon content in cell walls are more sensitive [33].…”
Section: Discussionsupporting
confidence: 65%
“…In this context, compared to invertebrates, fish have been proven to be particularly sensitive to Al exposition, in neutral to basic water a no effect concentration of 100 µg/l Al was reported for trouts. In contrast, marine studies on the ecotoxicological impact of galvanic anodes are scarce [17]. So far, very little attention has been paid to studying the toxicity and accumulation of Al in benthic organisms.…”
Background
Cathodic protection by sacrificial anodes composed of aluminum-zinc-indium alloys is often applied to protect offshore support structures of wind turbines from corrosion. Given the considerable growth of renewable energies and thus offshore wind farms in Germany over the last decade, increasing levels of aluminum, indium and zinc are released to the marine environment. Although these metals are ecotoxicologically well-studied, data regarding their impact on marine organisms, especially sediment-dwelling species, as well as possible ecotoxicological effects of galvanic anodes are scarce. To investigate possible ecotoxicological effects to the marine environment, the diatom Phaedactylum tricornutum, the bacterium Aliivibrio fischeri and the amphipod Corophium volutator were exposed to dissolved galvanic anodes and solutions of aluminum and zinc, respectively, in standardized laboratory tests using natural seawater. In addition to acute toxicological effects, the uptake of these elements by C. volutator was investigated.
Results
The investigated anode material caused no acute toxicity to the tested bacteria and only weak but significant effects on algal growth. In case of the amphipods, the single elements Al and Zn showed significant effects only at the highest tested concentrations. Moreover, an accumulation of Al and In was observed in the crustacea species.
Conclusions
Overall, the findings of this study indicated no direct environmental impact on the tested marine organisms by the use of galvanic anodes for cathodic protection. However, the accumulation of metals in, e.g., crustaceans might enhance their trophic transfer within the marine food web.
“…There has been an upsurge of interest in the effects of Al on marine organisms in recent years. With reference to marine phytoplankton, recent studies have reported both the toxicity (Gillmore et al, 2016;Golding et al, 2015) and the beneficial effects of Al on marine phytoplankton growth (Liu et al, 2018;Zhou et al, 2018aZhou et al, , 2018bZhou et al, , 2016. However, little is known about the uptake kinetics and the intracellular fate of Al in marine phytoplankton, which are important if we are to understand the mechanisms responsible for the biological effects of Al.…”
Aluminum (Al) is widespread in the environment including the ocean. The effects of Al on marine organisms have attracted more and more attention in recent years. However, the mechanisms of uptake of Al by marine organisms and the subcellular distribution of Al once assimilated are unknown. Here we report the uptake and subcellular distribution of Al in a marine diatom Thalassiosira weissflogii. Short-term (< 120 min) uptake experiments showed that the Al uptake rate by the diatom was 0.033 ± 0.013 fmol/cell/min (internalization flux normalized to the exposure Al concentration of 2 µM = 0.034 ± 0.013 nmol•m-2 •min-1 •nM-1). Subcellular fractionation experiments showed that the internalized Al was partitioned to subcellular components in the following order: granules (69 ± 5%) > debris (17 ± 4%) > organelles (12 ± 2%) > heat-stable peptides (HSP) (~2%) > heat-denaturable proteins (HDP) (< 1%), indicating that the majority of intracellular Al was detoxified and stored in inorganic forms. The subcellular distribution of Al in the diatom is different from that of Al in freshwater green algae, in which most of the internalized Al is partitioned to organelles. We also evaluated an artificial seawater-based EDTA rinse solution to remove Al adsorbed on the diatom cell surface. Overall, our study provides new information to understand the mechanisms of uptake of Al by marine diatoms, and the mechanisms responsible for the biological effects (both toxic and beneficial) of Al on the growth of marine phytoplankton, especially diatoms.
“…3) analysis of the cultured C. meneghiniana , from which the Al species associated with the organic components of the Al-bearing lake diatoms were determined. Notably, the specific mechanisms, explaining why diatoms take up Al into their frustules and how Al is transported or distributed between the inorganic and organic components of diatoms are unknown and have never been explored 35 .Fig. 5Al/Si atomic ratios of cultured diatoms and their frustules.…”
Diatoms play an important role in marine biogeochemical cycle of aluminum (Al), as dissolved Al is taken up by diatoms to build their siliceous frustules and is involved in the sedimentation of diatomaceous biogenic silica (BSi). The Al incorporation in BSi facilitates decreasing the dissolution of marine BSi and thus substantially influences the biochemical processes driven by diatoms, such as CO2 sequestration. However, the role of lake BSi in the terrestrial biochemical Al cycle has not been explored, though lakes represent the second-largest sink for BSi. By identifying the previously unexplored high Al/Si atomic ratios (up to 0.052) in lake BSi, here we show lake BSi is a large terrestrial Al pool due to its high Al content, and lake sedimentary BSi constitutes a significant global sink for Al, which is on the same magnitude as the Al sink in global oceans.
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