Evaluation of redox-sensitive metals in marine surface sediments influenced by the oxygen minimum zone of the Humboldt Current System, Northern Chile

Castillo, Alexis; Valdés, Jorge; Sifeddine, Abdelfettah; Vega, Sue-Ellen; Díaz-Ochoa, Javier; Marambio, Yery

doi:10.1016/j.ijsrc.2018.08.005

Cited by 14 publications

(14 citation statements)

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“… Besaury et al (2013) also reported decrease in the ratio of available/total copper concentration alongside an increase of total organic carbon in marine sediments of Chañaral Bay in northern Chile. Thus, it is possible that the low-oxygen levels recorded coupled with the high quantity of OM previously reported both MB and OL zones ( Isla et al, 2010 ; Castillo et al, 2019 ) increase the geochemical sequestration of TMs and therefore controls bioavailable concentrations due to formation of non-labile complexes in the sediments ( Strom et al, 2011 ; Cyriac et al, 2021 ). Nevertheless, naturally occurring processes linked to changes in pH, salinity, decomposition and mineralization can favor the release of mobile metal fractions from the sediment to the overlying water, facilitating bioaccumulation processes within the benthic food webs ( Chakraborty et al, 2016 ).…”

Section: Discussionmentioning

confidence: 99%

“…The northern Chilean coast is especially sensitive to the oxygen decline and pollution increase due to both raw sewage input from urban areas and intensive maritime traffic closely linked with mining transport, leading to significant implications on the accumulation of pollutants in marine sediments ( Valdés et al, 2014 ; Castillo et al, 2019 ). Which in turn could substantially affect microbial communities in the biogeochemical transformation of TMs, leading to modifications to ecosystem processes and functions ( Glass et al, 2015 ; Coclet et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

“… Campbell and Kirchman (2012) explain the decoupling between abundance and microbial activity as a result of grazing and virus lysis. Interestingly, sediment chemistry can affect the efficiency of nucleic acid extraction and PCR amplification, especially in polluted sediments like those of MB ( Valdés et al, 2005 ; Valdés, 2012 ; Castillo et al, 2019 ), where organic and inorganic compounds bind to the sediment ( Sander et al, 2015 ). It is also important to note that the potential bias in the differential nucleic acids extraction and amplification could generate an underestimation of some groups diversity ( Cardoso et al, 2017 ; Birrer et al, 2018 ).…”

Section: Discussionmentioning

confidence: 99%

“…MB is located in the southeastern Pacific on the coast of the Atacama Desert and has been considered a semi-enclosed system with high biological production ( Marín et al, 2003 ), strongly anthropized via the development of multiple mineral exporting harbors and a thermoelectric plant, leading to significant implications on the heavy metal (HM) accumulation in sediments ( Valdés, 2012 ; Castillo et al, 2019 ; Zárate et al, 2021 ). OL is located approximately 210 km north of MB near the city of Iquique ( Isla et al, 2010 ).…”

Section: Methodsmentioning

confidence: 99%

“…Briefly, the content of TC, TN, and TS was measured by analyzing ~3 mg of dry sediment on a LECO CHNS elemental analyzer (2400 series II, Perkin Elmer). Then the analytical procedure was verified with the analysis of sulfanilic acid (C 6 H 7 NO 3 S) as a reference material ( Castillo et al, 2019 ). At the collection sites, pH, salinity, conductivity, dissolved oxygen (DO), and temperature (°C) of the water column were measured using a CTD-O profiler (SBE 19 plus V2 Sea cat, SeaBird).…”

Section: Methodsmentioning

confidence: 99%

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Spatial co-occurrence patterns of benthic microbial assemblage in response to trace metals in the Atacama Desert Coastline

et al. 2023

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Taxonomic and functional microbial communities may respond differently to anthropogenic coastal impacts, but ecological quality monitoring assessments using environmental DNA and RNA (eDNA/eRNA) in response to pollution are poorly understood. In the present study, we investigated the utility of the co-occurrence network approach’s to comprehensively explore both structure and potential functions of benthic marine microbial communities and their responses to Cu and Fe fractioning from two sediment deposition coastal zones of northern Chile via 16S rRNA gene metabarcoding. The results revealed substantial differences in the microbial communities, with the predominance of two distinct module hubs based on study zone. This indicates that habitat influences microbial co-occurrence networks. Indeed, the discriminant analysis allowed us to identify keystone taxa with significant differences in eDNA and eRNA comparison between sampled zones, revealing that Beggiatoaceae, Carnobacteriaceae, and Nitrosococcaceae were the primary representatives from Off Loa, whereas Enterobacteriaceae, Corynebacteriaceae, Latescibacteraceae, and Clostridiaceae were the families responsible for the observed changes in Mejillones Bay. The quantitative evidence from the multivariate analyses supports that the benthic microbial assemblages’ features were linked to specific environments associated with Cu and Fe fractions, mainly in the Bay. Furthermore, the predicted functional microbial structure suggested that transporters and DNA repair allow the communities to respond to metals and endure the interacting variable environmental factors like dissolved oxygen, temperature, and salinity. Moreover, some active taxa recovered are associated with anthropogenic impact, potentially harboring antibiotic resistance and other threats in the coastal zone. Overall, the method of scoping eRNA in parallel with eDNA applied here has the capacity to significantly enhance the spatial and functional understanding of real-time microbial assemblages and, in turn, would have the potential to increase the acuity of biomonitoring programs key to responding to immediate management needs for the marine environment.

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