Individual and molecular level effects of produced water contaminants on nauplii and adult females of Calanus finmarchicus

Abstract

In the Barents Sea region new petroleum fields are discovered yearly and extraction of petroleum products is expected to increase in the upcoming years. Despite enhanced technology and stricter governmental legislation, establishment of the petroleum industry in the Barents Sea may potentially introduce a new source of contamination to the area, as some discharges of produced water will be allowed. Whether the presence of produced water poses a risk to the Arctic marine life remains to be investigated. The aim of this study was to examine effects of exposure to several compounds found in produced water-a mixture of selected organic compounds (APW), radium-226 ((226)Ra), barium (Ba), and a scale inhibitor-on the copepod species Calanus finmarchicus. Experiments were performed using exposure concentrations at realistic levels based on those detected in the vicinity of known discharge points. The influence of lethal and sublethal effects on early life stages was determined and significantly lower survival in the APW exposure groups was found. In the Ba treatment the life stage development did not proceed to the same advanced stages as observed in the control (filtered sea water). The scale inhibitor and (226)Ra treatments showed no significant difference from control. In addition, adult females were exposed to APW, (226)Ra, and a mixture of the two. Both individual-level effects (egg production and feeding) and molecular-level effects (gene expression) were assessed. On the individual level endpoints, only treatments including APW produced an effect compared to control. However, on the molecular level the possibility that also (226)Ra induced toxicologically relevant effects cannot be ruled out.

Toxicity of dissolved and precipitated forms of barium to a freshwater alga (Chlorella sp. 12) and water flea (Ceriodaphnia dubia)

“…Mechanisms of barium toxicity to water fleas will be dependent on the barium form. Precipitated barium sulfate may be ingested by the water fleas, as has been observed in marine copepods (Jensen et al 2016), in which it has no nutritional value and may obstruct the digestive tract. Barium is a physiological antagonist for potassium, and it is thought that cells become deficient in potassium when barium blocks the potassium channel of the Na þ /K þ pump in the cell membrane, resulting in reduced excitability of muscle fibers and muscle paralysis (Oskarsson 2014).…”

Gamma radiation induces dose-dependent oxidative stress and transcriptional alterations in the freshwater crustacean Daphnia magna

“…Transcriptomic analysis was performed using Agilent custom 60,000-feature D. magna oligonucleotide microarrays and 50 ng input RNA according to Agilent's standard protocol "One-Color Microarray-Based Gene Expression Analysis, version 6.5", with modifications (Song et al, 2016). Raw microarray data (signal intensity) was extracted from scanned images using the Feature Extraction software v10.7 (Agilent), and data corrected for baseline variance (normexp method), inter-array variance (quantile method), filtered for low expression probes and technical replicate probes merged using the Bioconductor package LIMMA (Smyth, 2005) in the R statistical environment v3.1.2, as previously described (Jensen et al, 2016).…”

Deciphering the Combined Effects of Environmental Stressors on Gene Transcription: A Conceptual Approach

“…Among all OMICS approaches, transcriptomics is the most frequently used in various multiple stressor studies and has proven to be a powerful tool for MoA characterization and toxicity pathway identification (e.g. ref 14,15 ). Altenburger and co-workers 12 critically reviewed the use of OMICS in 41 mixture toxicity studies in the period of 2002 to 2011 and reported that half of the studies employed transcriptomics for elucidating the combined toxicity at the molecular level.…”