Population- and sex-specific sensitivity of the marine amphipod Allorchestes compressa to metal exposure.

The sensitivity to contaminants of natural populations varies greatly depending on their historical exposure and on the sex of the individual. These factors result in great uncertainty in ecotoxicological risk assessments and challenge the protection of marine biodiversity. This study investigated the role of background pollution in the environment in shaping the sensitivity of males and females of the common marine amphipod Allorchestes compressa to the common trace marine pollutant, copper (Cu). Female and male amphipods were collected from two sites: Geelong (the polluted site) and Clifton Springs (the clean site). Amphipods were exposed to Cu treatments of 0, 50, 100, and 250 µg/L for 10 days, followed by a 10-day recovery period. Cu-exposed males from Geelong showed a reduction in feeding rate at a higher Cu concentration than males from Clifton Springs, suggesting that they have a higher tolerance to Cu than males from Clifton Springs. This can be explained by their higher base level of metallothioneins (MTs) and glutathione-S-transferase (GST), the key physiological responses for detoxification and defence against damages from Cu toxicity. Males showed a higher tolerance to Cu than females. This pattern was similar in both populations, which may be associated with a higher level of GST. During the recovery period, only males from Geelong fully recovered to the control level. Our results emphasize the importance of considering population- and sex-specific sensitivity of invertebrates to contaminants in ecotoxicological risk assessments.

Effects of surface texture and interrelated properties on marine biofouling: a systematic review.

This systematic review examines effects of surface texture on marine biofouling and characterizes key research methodologies. Seventy-five published articles met selection criteria for qualitative analysis; experimental data from 36 underwent quantitative meta-analysis. Most studies investigated fouling mechanisms and antifouling performance only in laboratory assays with one to several test species. Textures were almost exclusively a single layer of regularly arranged geometric features rather than complex hierarchical or irregular designs. Textures in general had no effect or an inconclusive effect on fouling in 46% of cases. However, effective textures more often decreased (35%) rather than increased (19%) fouling. Complex designs were more effective against fouling (51%) than were regular geometric features (32%). Ratios of feature height, width, or pitch to organism body length were significant influences. The authors recommend further research on promising complex and hierarchical texture designs with more test species, as well as field studies to ground-truth laboratory results.

eDNA metabarcoding reveals biodiversity and depth stratification patterns of dinoflagellate assemblages within the epipelagic zone of the western Coral Sea.

BACKGROUND: Dinoflagellates play critical roles in the functioning of marine ecosystems but also may pose a hazard to human and ecosystem health by causing harmful algal blooms (HABs). The Coral Sea is a biodiversity hotspot, but its dinoflagellate assemblages in pelagic waters have not been studied by modern sequencing methods. We used metabarcoding of the 18 S rRNA V4 amplicon to assess the diversity and structure of dinoflagellate assemblages throughout the water column to a depth of 150 m at three stations in the Western Coral Sea. Additionally, at one station we compared metabarcoding with morphological methods to optimise identification and detection of dinoflagellates. RESULTS: Stratification of dinoflagellate assemblages was evident in depth-specific relative abundances of taxonomic groups; the greatest difference was between the 5-30 m assemblages and the 130-150 m assemblages. The relative abundance of Dinophyceae (photosynthetic and heterotrophic) decreased with increasing depth, whereas that of Syndiniales (parasitic) increased with increasing depth. The composition of major taxonomic groups was similar among stations. Taxonomic richness and diversity of amplicon sequence variants (ASVs) were similar among depths and stations; however, the abundance of dominant taxa was highest within 0-30 m, and the abundance of rare taxa was highest within 130-150 m, indicating adaptations to specific depth strata. The number of unclassified ASVs at the family and species levels was very high, particularly for Syndinian representatives. CONCLUSIONS: Dinoflagellate assemblages in open water of the Coral Sea are highly diverse and taxonomically stratified by depth; patterns of relative abundance along the depth gradient reflect environmental factors and ecological processes. Metabarcoding detects more species richness than does traditional microscopical methods of sample analysis, yet the methods are complementary, with morphological analysis revealing additional richness. The large number of unclassified dinoflagellate-ASVs indicates a need for improved taxonomic reference databases and suggests presence of dinoflagellate-crypto and-morphospecies.

Salting-out assisted liquid-liquid extraction combined with LC-MS/MS for the simultaneous determination of seven organic UV filters in environmental water samples: method development and application.

Organic UV filters (OUVFs), the active ingredient in sunscreens, are of environmental concern due to reported ecotoxicological effects in aquatic biota. Determining the environmental concentrations of these chemicals is essential for understanding their fate and potential environmental risk. Salting-out assisted liquid-liquid extraction (SALLE) coupled with liquid-chromatography tandem mass spectrometry (LC-MS/MS) was developed for simultaneous extraction, separation, and quantification of seven OUVFs (2,4-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 4-methylbenzylidene camphor, butyl-methoxy-dibenzoyl methane, octocrylene, octyl methoxycinnamate, and oxybenzone). Method detection limits (MDLs) ranged from 11 to 45 ng/L and practical quantification limits (PQLs) from 33 to 135 ng/L. Method trueness, evaluated in terms of recovery, was 69-127%. Inter-day and intra-day variability was < 6% RSD. The coefficients of determination were > 0.97. The method was applied to river and seawater samples collected at 19 sites in and near Port Phillip Bay, Australia, and temporal variation in OUVF concentrations was studied at two sites. Concentrations of OUVF were detected at 10 sites; concentrations of individual OUVFs were 51-7968 ng/L, and the maximum total OUVF concentration detected at a site was 8431 ng/L. Recreational activity and water residence time at the site contributed to OUVF's environmental presence and persistence. The benefits of the SALLE-LC-MS/MS method include its simple operation, good selectivity, precision over a wide linear range, and that obtained extracts can be directly injected into the LC-MS/MS, overall making it an attractive method for the determination of these OUVFs in environmental water matrices. To our knowledge, this is the first report of the occurrence of OUVFs in Port Phillip Bay, Australia.

Trends in environmental and toxicity research on organic ultraviolet filters: A scientometric review.

In recent decades, the potential toxicological and environmental effects of organic ultraviolet filters (OUVF) have received growing attention. The number of studies in this area has increased; however, presently there is no scientometric perspective addressing this topic. The purpose of this study is to identify the intellectual base and research front using the visualization and analysis software, CiteSpace. We retrieved 453 articles, published in print or online as an early-access article between 2002 and 2020, from the Web of Science with a topic search related to OUVFs, environment, and toxicology. We then analysed synthesized networks of co-authorship (author, institution, country), co-citation (author, document, journal) and co-occurring keywords. The annual publication output has trended upwards since 2002. Authors based in China accounted for 29.4% of the total publications, followed by USA (17.4%); but overall publications from Switzerland and Spain were more influential. Major research themes identified included OUVF concentrations in aquatic environments, and hormonal effects. Emerging themes included improving the sensitivity of analytical detection methods for both OUVFs and their metabolites, consequences of OUVF transport to the marine environment, and concerns over prenatal exposure. Based on keyword analysis, benzophenone-3, 4-methylbenzylidene-camphor, 3-benzylidene camphor, and ethylhexyl-methoxycinnamate are the most studied OUVFs, and effects on estrogenic activity, gene expression, reproduction, and more recently, oxidative stress, have received most attention from a toxicological perspective. Other prominent topics were sources of environmental contamination and ecological risk assessments. This study maps the major research domains of OUVF environmental toxicology research; explanations and implications of the findings are discussed; and emerging trends highlighted.

A systematic review and ecological risk assessment for organic ultraviolet filters in aquatic environments.

Organic ultraviolet filters (OUVFs) are used in a wide range of manufactured products including personal care (e.g. sunscreens) and plastic items. This review summarizes the available data regarding the toxic effects of OUVFs on marine and freshwater organisms and generates the predicted no-effect concentration (PNEC) values necessary for assessing ecological risk. Through a systematic search of the literature, 89 studies were identified and ecotoxicological data extracted. Collectively, these studies described toxicity testing with 39 OUVF from 10 structural classes, with derivatives of benzophenones (49%) and camphors (16%) most studied. There was a bias towards selecting freshwater species (61%), and evaluating single OUVF effects (87%) rather than OUVF mixtures. Short-term (acute) experimentation (58%) was marginally more common than long-term (chronic) testing (42%). Reproductive, developmental, genetic, and neurological toxicity were the most commonly identified effects in aquatic organism, and were associated with molecular interactions with steroid receptors, DNA, or the production of reactive oxygen species. Species sensitivity distribution and/or assessment factors were used to calculate PNECs for 22 OUVFs and the risk quotients for 12 OUVFs. When using maximum concentrations, high risk was observed for six OUVFs in marine environments (4-methylbenzylidene-camphor, octocrylene, padimate-O, benzophenone-1, and oxybenzone, ethylhexyl-4-methoxycinnamate), and for four OUVFs in freshwater environments (ethylhexyl-4-methoxycinnamate, octocrylene, avobenzone and oxybenzone). When using median concentrations, a risk to marine environments was observed for oxybenzone. The results of this review underline that there is limited knowledge of the pathological effects of OUVFs and their metabolites in aquatic environments, and this inhibits the development of informed water-quality guidelines.

Additives migrating from 3D-printed plastic induce developmental toxicity and neuro-behavioural alterations in early life zebrafish (Danio rerio).

The environmental impact of exposure to 3D-printed plastics as well as potential migration of toxic chemicals from 3D-printed plastics remains largely unexplored. In this work we applied leachates from plastics fabricated using a stereolithography (SLA) process to early developmental stages of zebrafish (Danio rerio) to investigate developmental toxicity and neurotoxicity. Migration of unpolymerized photoinitiator, 1-hydroxycyclohexyl phenyl ketone (1-HCHPK) from a plastic solid phase to aqueous media at up to 200 mg/L in the first 24 h was detected using gas chromatography-mass spectrometry. Both plastic extracts (LC50 22.25% v/v) and 1-HCHPK (LC50 60 mg/L) induced mortality and teratogenicity within 48 h of exposure. Developmental toxicity correlated with in situ generation of reactive oxygen species (ROS), an increase in lipid peroxidation and protein carbonylation markers and enhanced activity of superoxide dismutase (SOD) and glutathione-S-transferase (GST) in embryos exposed to concentrations as low as 20% v/v for plastic extracts and 16 mg/L for 1-HCHPK. ROS-induced cellular damage led to induction of caspase-dependent apoptosis which could be pharmacologically inhibited with both antioxidant ascorbic acid and a pan-caspase inhibitor. Neuro-behavioral analysis showed that exposure to plastic leachates reduced spontaneous embryonic movement in 24-36 hpf embryos. Plastic extracts in concentrations above 20% v/v induced rapid retardation of locomotion, changes in photomotor response and habituation to photic stimuli with progressive paralysis in 120 hpf larvae. Significantly decreased acetylcholinesterase (AChE) activity with lack of any CNS-specific apoptotic phenotypes as well as lack of changes in motor neuron density, axonal growth, muscle segment integrity or presence of myoseptal defects were detected upon exposure to plastic extracts during embryogenesis. Considering implications of the results for environmental risk assessment and the growing usage of 3D-printing technologies, we speculate that some 3D-printed plastic waste may represent a significant and yet very poorly uncharacterized environmental hazard that merits further investigation on a range of aquatic and terrestrial species.

3D-Printed Chips: Compatibility of Additive Manufacturing Photopolymeric Substrata with Biological Applications.

Additive manufacturing (AM) is ideal for building adaptable, structurally complex, three-dimensional, monolithic lab-on-chip (LOC) devices from only a computer design file. Consequently, it has potential to advance micro- to milllifluidic LOC design, prototyping, and production and further its application in areas of biomedical and biological research. However, its application in these areas has been hampered due to material biocompatibility concerns. In this review, we summarise commonly used AM techniques: vat polymerisation and material jetting. We discuss factors influencing material biocompatibility as well as methods to mitigate material toxicity and thus promote its application in these research fields.

Characterization of 3D-Printed Moulds for Soft Lithography of Millifluidic Devices.

Increased demand for inexpensive and rapid prototyping methods for micro- and millifluidic lab-on-a-chip (LOC) devices has stimulated considerable interest in alternative cost-effective fabrication techniques. Additive manufacturing (AM)-also called three-dimensional (3D) printing-provides an attractive alternative to conventional fabrication techniques. AM has been used to produce LOC master moulds from which positive replicas are made using soft-lithography and a biocompatible elastomer, poly(dimethylsiloxane) (PDMS). Here we characterize moulds made using two AM methods-stereolithography (SLA) and material-jetting (MJ)-and the positive replicas produced by soft lithography and PDMS moulding. The results showed that SLA, more than MJ, produced finer part resolution and finer tuning of feature geometry. Furthermore, as assessed by zebrafish (Danio rerio) biotoxicity tests, there was no toxicity observed in SLA and MJ moulded PDMS replicas. We conclude that SLA, utilizing commercially available printers and resins, combined with PDMS soft-lithography, is a simple and easily accessible technique that lends its self particularly well to the fabrication of biocompatible millifluidic devices, highly suited to the in-situ analysis of small model organisms.

Impacts on the seagrass, Zostera nigricaulis, from the herbicide Fusilade Forte® used in the management of Spartina anglica infestations.

The herbicide Fusilade Forte® (FF) is widely applied in agricultural weed management and in the management of the invasive saltmarsh grass, Spartina anglica (ricegrass or cordgrass). FF (active ingredient fluazifop-P acid, FPA) is selective for poaceous grasses. Its primary mode of action is inhibition of the acetyl coenzyme-A carboxylase (ACCase) specific to this taxonomic group, and its secondary mode is by promotion of oxidative stress. FF is applied to S. anglica infestations in the intertidal zone, in proximity to seagrass meadows. Despite the potential for vital seagrass ecosystems to be exposed to FF, there is limited knowledge of any potential impacts. We investigated impacts of FPA on the endemic Australian seagrass, Zostera nigricaulis, measuring ACCase activity and parameters that reflect oxidative stress: photosynthetic performance, lipid peroxidation and photosynthetic pigment content. Seagrass was exposed to FF (0.01-10mgL-1 FPA and a control) for 7d, followed by a 7-d recovery in uncontaminated seawater. An enzyme assay demonstrated that FPA ≤10mgL-1 did not inhibit the activity of ACCase isolated from Z. nigricaulis, demonstrating that this seagrass is resistant to FF's primary mode of action. However, physiological impacts occurred following 7 days exposure to ≥0.1mgL-1 FPA, including up to a 72% reduction in photosynthetic pigment concentration. After 7-d recovery, photosynthetic pigment content improved in treatment plants; however, treated plants exhibited higher levels of lipid peroxidation. This study demonstrates that while Z. nigricaulis is resistant to FF's primary mode of action, significant physiological impacts occur following 7 days exposure to ≥0.1mgL-1 FPA. This study provides valuable information on the effects of FF on a non-target species that can better inform approaches to Spartina management in coastal seagrass ecosystems.