Microplastics in the Coral Reef Systems from Xisha Islands of South China Sea.

The impacts of microplastics on coral reefs are gaining attention due to findings that microplastics affect coral health. This work investigated the distribution and characteristics of microplastics in the seawater, fish, and corals in 3 atolls from the Xisha Islands of South China Sea. In the seawater samples, microplastics were detected in the outer reef slopes, reef flats, and lagoons with abundances ranging from 0.2 to 11.2, 1.0 to 12.2, and 1.0 to 45.2 items L-1, respectively. Microplastic abundance was 0-12.0 items individual-1 (0-4.7 items g-1) in fish and 1.0-44.0 items individual-1(0.02-1.3 items g-1) in coral. The predominant shape and polymer of microplastics in seawater, fish, and coral were fibrous rayon and polyethylene terephthalate (PET). Microplastic sizes primarily ranged from 20-330 µm in both the seawater and fish, while there were relatively more 1-5 mm microplastics in the corals. The shape, size, color, and polymer type distribution patterns of microplastics in seawater more closely resembled those in fish gills than those in fish gastrointestinal tracts or coral samples. This study shows that microplastics are abundant in these coral reef systems and they are captured by fish or "trapped" by corals.

Elder fish means more microplastics? Alaska pollock microplastic story in the Bering Sea.

Marine microplastics are an increasingly big concern. We analyze the occurrence of microplastics in Alaska pollock (Gadus chalcogrammus) across 2+ to 12+ ages sampled from the Bering Sea. Results show that 85% of the fish have ingested microplastics and elder fish ingest more with over a third of microplastics in the 100- to 500-micrometer size range, indicating the prevalence of microplastics in Alaska pollock distributed in the Bering Sea. A positive linear relationship is obtained between fish age and microplastic size. Meanwhile, the number of polymer types increases in elder fish. The link between microplastic characteristics in Alaska pollock and the surrounding seawater suggests an extended spatial impact of microplastics. The impact of age-related microplastic ingestion on the population quality of Alaska pollock is still unknown. Therefore, we need to further investigate the potential impact of microplastics on marine organisms and the marine ecosystem, taking age as an important factor.

Atmospheric microplastics in the Northwestern Pacific Ocean: Distribution, source, and deposition.

Microplastic pollution is recognized as a ubiquitous global issue. However, limited information is available concerning microplastics in the marine air. Here we present the occurrence and distribution of atmospheric microplastics in the Northwestern Pacific Ocean, with abundance ranging from 0.0046 to 0.064 items/m3. The microplastics were in various shapes and polymer types, of which fibrous rayon (67%) and polyethylene terephthalate (PET, 23%) accounted for the majority. The atmospheric microplastics in the pelagic area showed higher abundance and smaller size compared to those in the nearshore area, indicating smaller-sized microplastics in the atmosphere might travel long distances over the ocean. The atmospheric microplastic distribution was not only affected by weather conditions but might also be related to the microplastic sources. The microplastic polymer types combined with the backward trajectory model analysis showed that atmospheric microplastics in the Northwestern Pacific Ocean mainly originated from the land and the adjacent oceanic atmosphere. Spearman's correlation coefficient of the relationship between the features of microplastics in the atmosphere and surface seawater tended to increase with increasing offshore distances. Our field-based research revealed that atmospheric microplastics were a non-negligible source of marine microplastic pollution.

Microplastics in global bivalve mollusks: A call for protocol standardization.

A growing body of evidence shows that microplastic pollution is ubiquitous in bivalve mollusks globally and is of particular concern due to its potential impact on human health. However, non-standardized sampling, processing, and analytical techniques increased the difficulty of direct comparisons among existing studies. Based on 61 peer-reviewed papers, we summarized the current knowledge of microplastics in bivalve mollusks globally and provided an in-depth analysis of factors affecting the outcome of microplastic data, with the main focus on the effects of different species and methodologies. We found no significant differences in microplastic abundance among genera from the same family but significant differences among bivalve families, indicating habitats play an important role in microplastic ingestion by bivalve mollusks. This also provided foundational knowledge for using epifaunal and infaunal bivalves to monitor microplastic pollution in water and sediment, respectively. Recommendations for microplastic monitoring protocol in bivalve mollusks were proposed according to the results of this review, covering (i) a sample size of at least 50 bivalves in the study area, (ii) the use of 10 % KOH as the digestion solution, and (iii) the pore size of a filter membrane of < 5 µm. Acknowledging the need for a standard procedure, more efforts towards protocol standardization used in long-term and large-scale microplastic monitoring programs in bivalve mollusks are needed.

Methods for microplastic sampling and analysis in the seawater and fresh water environment.

Microplastic (plastic smaller than 5mm in size) is ubiquitous around the world both in the ocean and the freshwater system. Due to their potential serious negative impact on marine organisms and human beings, marine microplastics have attracted worldwide attention in the past decade. Information and knowledge of the spatial and temporal distribution of marine microplastics are crucial for accurately assessing our current and future environmental health conditions. This is also important for developing mitigation plans and measures to protect our environment. Since the measured microplastic pollution level is closely related to the sampling methods and identification techniques, it is important to employ standardized sampling and analysis operation procedures for cross-comparison. In this chapter, we present the basic sampling, sample pretreatment and microplastic identification techniques involved in microplastic pollution assessment and discuss the adaptability of different sampling and pretreatment methods. The pros and cons of different techniques are also discussed.

Microplastics in four bivalve species and basis for using bivalves as bioindicators of microplastic pollution.

Microplastics in bivalves have caused widespread concern due to their potential health risk to humans. In this study, microplastics in the digestive systems of four locally cultured bivalve species (scallop Chlamys farreri, mussel Mytilus galloprovincialis, oyster Crassostrea gigas, and clam Ruditapes philippinarum) in Qingdao, China, were analyzed and detected in 233 out of 290 bivalve samples (80%) over four seasons. The microplastic abundance in four species of bivalves ranged between 0.5 and 3.3 items/individual or 0.3 and 20.1 items/g wet weight digestive system, with significant species-specific and region-specific differences but no season-specific differences. Microfiber was the most predominant shape of all microplastics found. Eighteen types of polymer with diameters between 7 and 5000 µm were identified by µ-FT-IR (505 of 587 suspected items identified as microplastics) with polyvinyl chloride (PVC) and rayon being the most abundant ones. Bivalves collected in summer contained more larger-sized microplastics. R. philippinarum accumulated more smaller-sized microplastics and showed different microplastic features compared with the other three species of bivalves. By comparing and analyzing the microplastic polymer types between each bivalve species and the ambient environment, microplastic in clam can best reflect the variability of microplastic polymer types in sediment among different areas. Mussels can reflect the variability of microplastic polymer types in water to an extent. Therefore, clam and mussel are recommended to serve as bioindicators for microplastic pollution in the sediment and water, respectively. The occurrence of microplastics pollution in bivalves worldwide is wide, and bivalves can act as the transporter of microplastics to humans. Our results suggest that bivalves have an important role as environmental bioindicators and the pollution of microplastics in bivalves needs attention.

Beyond Smiles: Static Expressions in Maxillary Protrusion and Associated Positivity.

Smiles play an important role in social perception. However, it is unclear whether a similar role is played by static facial features associated with smiles (e.g., stretched mouth and visible teeth). In dental science, maxillary dental protrusions increase the baring of the teeth and thus produce partial facial features of a smile even when the individual is not choosing to smile, whereas mandibular dental protrusions do not. We conducted three experiments to assess whether individuals ascribe positive evaluations to these facial features, which are not genuine emotional expressions. In Experiment 1, participants viewed facial photographs of maxillary and mandibular protrusions and indicated the smiling and emotional status of the faces. The results showed that, while no difference was observed in participants' perception of the presence of a smile across both types of dental protrusion, participants felt more positive to faces with maxillary than mandibular protrusions. In Experiment 2, participants completed an Implicit Association Test (IAT) test measuring implicit attitudes toward faces with maxillary vs. mandibular protrusions. The results showed that participants had more positive attitude toward faces with maxillary than mandibular protrusions. In Experiment 3, individuals with either maxillary or mandibular protrusions completed the same IAT test to assess whether any preference would be affected by in-group/out-group preferences. The results showed both groups had more positive attitudes toward faces with maxillary protrusion, indicating that this preference is independent of the group effect. These findings suggest that facial features associated with smiles are viewed positively in social situations. We discuss this in terms of the social-function account.

New insights into the toxic interactions of polyvinyl chloride microplastics with bovine serum albumin.

The binding interaction between emerging pollutant polyvinyl chloride microplastics (PVC MPs) and bovine serum albumin (BSA) was studied by fluorescence spectroscopy, resonance scattering spectroscopy (RLS), UV-visible (UV-vis) absorption spectroscopy, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. Fluorescence results revealed that the fluorescence quenching of BSA induced by PVC MPs was originated from the formation of BSA-PVC complex in static quenching mode. According to Stern-Volmer equation, the binding constants (Ka) between PVC MPs and BSA at different temperatures were obtained, and the number of binding sites was 1.62. The thermodynamic parameters, enthalpy change (ΔH), entropy change (ΔS), and free energy change (ΔG) were calculated to be - 41.77 kJ mol-1, 43.17 J mol-1 K-1, and - 54.63 kJ mol-1 via Van't Hoff equation, indicating electrostatic interaction played a key role in the formation of BSA-PVC complex spontaneously. In addition, the alterations of microenvironment and secondary structure in BSA induced by PVC MPs were further confirmed by synchronous fluorescence spectra, UV-vis, FT-IR, and CD. This work not only provides further information for better understanding the binding interaction of PVC MPs with BSA, but also elucidates the potential biological toxicity of MPs at a molecular level.

An examination of the occurrence and potential risks of microplastics across various shellfish.

The ingestion of microplastics by shellfish pose a potential health risk for human via seafood consumption. This study investigated and compared the contamination levels and potential human health risks of microplastics in the digestive system of commercial shellfish from North (Qingdao) and South (Xiamen) China. Microplastics were detected in 70%-100% of shellfish samples from Qingdao and 70%-90% of shellfish samples from Xiamen, with abundances ranging from 1.2 to 4.1 items/individual (or 0.8-4.4 items/g, wet weight of digestive system) in shellfish from Qingdao and 1.3-6.0 items/individual (or 2.1-4.0 items/g) in shellfish from Xiamen. The microplastic composition was dominated by rayon and tended to be fibrous in shape, and white, black, and transparent in color. Microplastics <500 µm were the dominant size range, in which the size range of 100-200 µm was the most abundant size. Features of microplastics in the water-dwelling shellfish were different from those of the sediment-dwelling shellfish, and the microplastic features in the shellfish correlated with the sampling region, shellfish length, total wet body weight, and wet weight of the digestive system. Risk assessment results revealed that the potential human health risk posed by microplastics from the digestive system of commercial shellfish was higher in Qingdao than Xiamen.

Effect of nitrogen levels and nitrogen ratios on lodging resistance and yield potential of winter wheat (Triticum aestivum L.).

Lodging is one of the constraints that limit wheat yields and quality due to the unexpected bending or breaking stems on wheat (Triticum aestivum L.) production worldwide. In addition to choosing lodging resistance varieties, husbandry practices also have a significant effect on lodging. Nitrogen management is one of the most common and efficient methods. A field experiment with Yangmai 20 as research material (a widely-used variety) was conducted to study the effects of different nitrogen levels and ratios on culm morphological, anatomical characters and chemical components and to explore the nitrogen application techniques for lodging tolerance and high yield. Results showed that some index of basal internodes, such as stem wall thickness, filling degree, lignin content, cellulose content, water-soluble carbohydrate (WSC) and WSC/N ratio, were positively and significantly correlated with culm lodging-resistant index (CLRI). As the increase of nitrogen level and basal nitrogen ratio, the basal internodes became slender and fragile with the thick stem wall, while filling degree, chemical components and the strength of the stem decreased gradually, which significantly increased the lodging risk. The response of grain yield to nitrogen doses was quadratic and grain yield reached the highest at the nitrogen ratio of 50%:10%:20%:20% (the ratio of nitrogen amount applied before sowing, at tillering stage, jointing stage and booting stage respectively, abbreviated as 5:1:2:2). These results suggested that for Yangmai 20, the planting density of 180×104ha-1, nitrogen level of 225 kg ha-1, and the ratio of 5: 1: 2: 2 effectively increased lodging resistance and grain yield. This combination of planting density and nitrogen level and ratio could effectively relieve the contradiction between high-yielding and anti-lodging.