Spatial and temporal variations in copper speciation in San Diego Bay

Blake, A. C.; Chadwick, D. B.; Zirino, Alberto; Rivera-Duarte, Ignacio

doi:10.1007/bf02803536

Cited by 35 publications

(39 citation statements)

References 23 publications

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“…The surface waters off the pier in the winter months are characterized by lower water temperature, a higher degree of mixing and more runoff from rains. The latter two of these could lead to episodic pulses of higher copper in surface waters, and although we have no direct measurements of seasonal copper at this location, it is well-known that runoff does tend increase copper levels in San Diego Bay, and the rainy winter months have significantly higher copper levels (Blake et al, 2004;Buck et al, 2007). Additionally, it could be that copper is also upwelled seasonally (Takesue and van Geen 2002).…”

Section: Discussionmentioning

confidence: 85%

Genomic island genes in a coastal marine Synechococcus strain confer enhanced tolerance to copper and oxidative stress

et al. 2013

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Highly variable regions called genomic islands are found in the genomes of marine picocyanobacteria, and have been predicted to be involved in niche adaptation and the ecological success of these microbes. These picocyanobacteria are typically highly sensitive to copper stress and thus, increased copper tolerance could confer a selective advantage under some conditions seen in the marine environment. Through targeted gene inactivation of genomic island genes that were known to be upregulated in response to copper stress in Synechococcus sp. strain CC9311, we found two genes (sync_1495 and sync_1217) conferred tolerance to both methyl viologen and copper stress in culture. The prevalence of one gene, sync_1495, was then investigated in natural samples, and had a predictable temporal variability in abundance at a coastal monitoring site with higher abundance in winter months. Together, this shows that genomic island genes can confer an adaptive advantage to specific stresses in marine Synechococcus, and may help structure their population diversity.

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Section: Discussionmentioning

confidence: 85%

Genomic island genes in a coastal marine Synechococcus strain confer enhanced tolerance to copper and oxidative stress

et al. 2013

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“…Although the Cu 2ϩ concentration is generally low (10 Ϫ14 M) in the surface waters of the open ocean, it can increase by 3 or 4 orders of magnitude below the euphotic zone (12), and a mixing event could thus cause a sharp increase in Cu 2ϩ concentrations. Furthermore, in coastal environments, a sharp spike in free-copper levels can occur after a heavy rain due mostly to anthropogenic inputs (6). Finally, there is evidence that dust deposition can introduce copper into surface waters (35).…”

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confidence: 99%

Coastal Strains of Marine Synechococcus Species Exhibit Increased Tolerance to Copper Shock and a Distinctive Transcriptional Response Relative to Those of Open-Ocean Strains

Stuart

Dupont

Johnson

et al. 2009

Appl Environ Microbiol

106

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Copper appears to be influencing the distribution and abundance of phytoplankton in marine environments, and cyanobacteria are thought to be the most sensitive of the phytoplankton groups to copper toxicity. By using growth assays of phylogenetically divergent clades, we found that coastal strains of marine Synechococcus species were more tolerant to copper shock than open-ocean strains. The global transcriptional response to two levels of copper shock were determined for both a coastal strain and an open-ocean strain of marine Synechococcus species using whole-genome expression microarrays. Both strains showed an osmoregulatory-like response, perhaps as a result of increasing membrane permeability. This could have implications for marine carbon cycling if copper shock leads to dissolved organic carbon leakage in Synechococcus species. The two strains additionally showed a common reduction in levels of photosynthesis-related gene transcripts. Contrastingly, the open-ocean strain showed a general stress response, whereas the coastal strain exhibited a more specifically oxidative or heavy-metal acclimation response that may be conferring tolerance. In addition, the coastal strain activated more regulatory elements and transporters, many of which are not conserved in other marine Synechococcus strains and may have been acquired by horizontal gene transfer. Thus, tolerance to copper shock in some marine Synechococcus strains may in part be a result of a generally increased ability to sense and respond in a more stress-specific manner.Marine Synechococcus and Prochlorococcus species are together thought to be responsible for at least 20% of global carbon fixation (25). They play such a significant role in the carbon cycle that it is essential to understand to which environmental stresses they are susceptible and how they respond. Cyanobacteria have been shown to be particularly sensitive to copper, for example, compared to other marine phytoplanktons (9). As a group, cyanobacteria have various levels of copper tolerance, with Prochlorococcus species thought to be more sensitive to copper than Synechococcus species (27). Within Synechococcus species, strain tolerance has been shown to vary (9), but those experiments with equilibrated copper levels were done prior to a better understanding of Synechococcus phylogenetic diversity.Applying a copper "shock" seems just as environmentally relevant as using equilibrated copper levels, since there are several mechanisms by which we could see sharp, rapid spikes of Cu 2ϩ concentrations in the surface waters where marine Synechococcus strains are found. Although the Cu 2ϩ concentration is generally low (10 Ϫ14 M) in the surface waters of the open ocean, it can increase by 3 or 4 orders of magnitude below the euphotic zone (12), and a mixing event could thus cause a sharp increase in Cu 2ϩ concentrations. Furthermore, in coastal environments, a sharp spike in free-copper levels can occur after a heavy rain due mostly to anthropogenic inputs (6). Finally, there is evidence that d...

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“…According to Largier et al (1997), hyper-saline estuaries are usually characterized by weak tide dispersion capacity, resulting in longer water resident time along the estuarine bed. So, as a result, these ecosystems tend to accumulate contaminants rather than export them to neighbor systems (Blake et al 2004). Another typical feature of these areas are the high evaporation rates, contributing to the concentration of solutes in the water column, inducing to coagulation and finally precipitation of insoluble authigenic minerals in surface sediment (Shumilin et al 2002).…”

Section: Resultsmentioning

confidence: 99%

Potentially mobile of heavy metals on the surface sediments in tropical hyper-saline and positive estuaries

Silva

Fonseca

Grotto

et al. 2017

An. Acad. Bras. Ciênc.

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Estuarine sediments represent important pools of trace metals, released from both anthropogenic and natural sources. Fluctuations in the water column physicochemical conditions, on the other hand, may transfer metals from solid to liquid compartment and resulting in contamination of the surrounding environment. The present research was carried out to evaluate the weakly bounded heavy metal levels in tropical hypersaline and positive estuaries, in order to quantify its potentially availability. The monitoring includes five metals (Cd, Cr, Cu, Pb, Zn) and cover nine estuaries in Rio Grande do Norte state/Brazil, including four hypersaline and five true estuaries. 50 surface sediment samples were collected in each estuary. At the same time, organic matter concentrations were evaluated in order to help explaining possible local variations in heavy metal levels. Organic matter results (0.7% -7.3%) suggest the positive Potengi estuary as the most critical environmental quality situation. On the other hand, according to heavy metals levels, both Conchas and Potengi estuaries registered the higher concentrations of Cr. The highest concentrations were observed in the hyper-saline estuaries, with the exception of the Zn. The present study revealed that the watershed occupation has significantly influenced the heavy metal concentrations in the estuaries.

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Spatial and temporal variations in copper speciation in San Diego Bay

Cited by 35 publications

References 23 publications

Genomic island genes in a coastal marine Synechococcus strain confer enhanced tolerance to copper and oxidative stress

Genomic island genes in a coastal marine Synechococcus strain confer enhanced tolerance to copper and oxidative stress

Coastal Strains of Marine Synechococcus Species Exhibit Increased Tolerance to Copper Shock and a Distinctive Transcriptional Response Relative to Those of Open-Ocean Strains

Potentially mobile of heavy metals on the surface sediments in tropical hyper-saline and positive estuaries

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