Microbial community structure and co-occurrence network stability in seawater and microplastic biofilms under prometryn pollution in marine ecosystems.

Prometryn has been extensively detected in marine environment because of its widespread usage in agriculture and aquaculture and has been concerns since its serious effects on aquatic organisms. However, its impact on the microbial community in the marine ecosystem including seawater and biofilm is still unclear. Therefore, a short-term indoor microcosm experiment of prometryn exposure was conducted. This study found that prometryn had a more significant impact on the structure and stability of the microbial community in seawater compared to microplastic biofilms. Additionally, we observed that the assembly of the microbial community in biofilms was more affected by stochastic processes than in seawater under the exposure of prometryn. Our study provided evidence for the increasing impact of the microbial communities under the stress of prometryn and microplastics.

Presence and distribution of triazine herbicides and their effects on microbial communities in the Laizhou Bay, Northern China.

This study investigated the distribution of triazine herbicides in the Laizhou Bay, China and found that the total concentrations of triazine herbicides in the seawater and sediments were 111.15-234.85 ng/L and 0.902-4.661 µg/kg, respectively. Triazine herbicides especially ametryn, atrazine, and simazine were negatively correlated with prokaryote diversity in the seawater. While ametryn, desethylatrazine and desisopropylatrazine had positively significant effects on eukaryotes Dinophyceae, Bacillariophyta, and Cercozoa in the sediments. Moreover, the degree of fragmentation of eukaryotic networks increased dramatically with the increasing numbers of removed nodes, but prokaryotic networks did not change with the decrease of nodes. In addition, the stability analysis and neutral community models revealed that eukaryotes were more sensitive to triazine herbicides than prokaryotes. These results suggest that triazine herbicides might affect the structure and interactions of microbial communities. Therefore, more attentions should be paid to the ecological risk of triazine herbicides in marine ecosystems.

Porous microplastics enhance polychlorinated biphenyls-induced thyroid disruption in juvenile Japanese flounder (Paralichthys olivaceus).

Microplastics and polychlorinated biphenyls are ubiquitous in the marine environments. To illuminate their combined biological impacts, juvenile Japanese flounder (Paralichthys olivaceus) were exposed to 500 ng/L PCBs alone or 500 ng/L PCBs plus 2, 20, and 200 µg/L 10-µm porous MPs for 21 days. Compared to PCBs alone, co-exposure to PCBs and 20, 200 µg/L MPs reduced fish body length and body weight, and the concurrence of MPs aggravated PCBs-induced thyroid-disrupting effects, including significantly decreased L-thyroxine and L-triiodothyronine levels, more severe damage to the thyroid tissue and gill morphology, and disturbance on the expression of hypothalamus-pituitary-thyroid axis genes. The PCBs concentrations in the seawater were decreased dramatically with the increase of MPs concentrations, confirming that MPs absorbed PCBs from the seawater. Our results demonstrated that MPs enhanced the thyroid disruption of PCBs, suggesting that the risk of MPs and thyroid-disrupting chemicals on marine organisms should be paid more attention.

Impacts of nanoplastics on life-history traits of marine rotifer (Brachionus plicatilis) are recovered after being transferred to clean seawater.

With the continuous accumulation of nanoplastics (NPs) in the ocean, it becomes urgent to explore their potential effects on filter-feeding zooplankton. This study exposed marine rotifer (Brachionus plicatilis) to 0, 20, 200, and 2000 µg/L of 70-nm polystyrene NPs (PS NPs) for two generations (F0 - F1), followed by two-generation (F2 - F3) culture in clean seawater, to investigate the impacts on life-history traits. The results showed that NPs were ingested by the rotifers within 10 min and reached a maximum level after 12 h of exposure. NPs were also observed in the feces of F0 and F1 generation rotifers and on the surface of F1 generation eggs. The intake of NPs inhibited microalgae ingestion, decreased body volume, delayed the first spawning time, reduced the total number of eggs and offspring of F0 and F1 generation. Moreover, 2000 µg/L NPs postponed the first hatching time of F0 generation eggs by 2.5 h, and the hatching time of F1 generation eggs was delayed by 7.3 h and 6.8 h under 200 and 2000 µg/L NPs exposure. The first spawning time and the first hatching time of rotifers were still significantly prolonged in the F2 generation, but other life-history traits returned to normal. After being cultured in clean seawater for two generations, all these indicators were recovered to the normal level. Overall, this study demonstrates that the life-history traits of marine rotifers could be flexibly changed with/without PS NPs exposure.

Polystyrene microplastics increase estrogenic effects of 17α-ethynylestradiol on male marine medaka (Oryzias melastigma).

Microplastics (MPs) and endocrine disrupting chemicals are ubiquitous pollutants in marine environments, but their combined ecological risk is unclear. This study exposed male marine medaka (Oryzias melastigma) to 10 ng/L 17α-ethynylestradiol (EE2) alone or EE2 plus 2, 20, and 200 µg/L polystyrene MPs for 28 days to investigate the impacts of MPs on the reproductive disruption of EE2. The results showed that 10 ng/L EE2 alone did not affect biometric parameters, while co-exposure to EE2 and 20, 200 µg/L MPs suppressed the growth and decreased gonadosomatic and hepatosomatic indices. Compared to EE2 alone, EE2 plus MPs exposure significantly increased plasma 17ß-estradiol (E2) levels in a dose-dependent manner, and co-exposure to EE2 and 20, 200 µg/L MPs significantly increased the ratios of E2/testosterone (T). Moreover, EE2 plus MPs exposure elevated the transcription levels of estrogen biomarker genes vitellogenin and choriogenin, and estrogen receptor (ERα and ERß). Morphological analysis also showed that co-exposure to EE2 and MPs induced more severe damage to the testes and livers, indicating that MPs increased the toxicity of EE2. The actual EE2 concentrations in the solution increased with the exposure concentrations of MPs, suggesting that MPs changed the fate and behavior of EE2 in the seawater. These findings demonstrate that MPs could increase the estrogenic effects of EE2 on marine fish, suggesting that the combined health risk of MPs and endocrine disrupting chemicals on marine organisms should be paid great attention.

Eelgrass (Zostera marina) and its epiphytic bacteria facilitate the sinking of microplastics in the seawater.

Marine microplastics have received considerable attention as a global environmental issue. However, despite the constant accumulation of microplastics in the ocean, their transport processes and mechanisms remain poorly understood. This study investigated microplastics in the sediments of seagrass meadows and nearby regions without seagrass along the Shandong coast and found that the sediment in the seagrass meadows was a sink for microplastics. Subsequently, we evaluated the influence of eelgrass (Zostera marina), a common coastal seagrass, on the sedimentation of suspended polystyrene microplastics. The results showed that 0.5, 1.0, and 2.0 g/L eelgrass leaves decreased the abundance of microplastics in seawater in a dose-dependent manner over a period of 3-48 h under shaking conditions at 120 rpm at 22 °C. After 48 h of shaking, microplastic abundances in the 0.5, 1.0, and 2.0 g/L eelgrass groups significantly decreased by 46.9%, 53.1%, and 88.4%, respectively. Microplastics can adhere to eelgrass leaves and form biofilms, which promoted the formation of white floc that traps the suspended microplastics, causing them to sink. Furthermore, two epiphytic bacteria (Vibrio and Exiguobacterium) isolated from the eelgrass leaves decreased the abundances of suspended microplastics by 95.7% and 94.5%, respectively, in 48 h by accelerating the formation of biofilms on the microplastics. Therefore, eelgrass and its epiphytic bacteria facilitated the sinking of microplastics and increased the accumulation of microplastics in the sediments of seagrass meadows in coastal regions.

Low-Light Image Enhancement Based on Multi-Path Interaction.

Due to the non-uniform illumination conditions, images captured by sensors often suffer from uneven brightness, low contrast and noise. In order to improve the quality of the image, in this paper, a multi-path interaction network is proposed to enhance the R, G, B channels, and then the three channels are combined into the color image and further adjusted in detail. In the multi-path interaction network, the feature maps in several encoding-decoding subnetworks are used to exchange information across paths, while a high-resolution path is retained to enrich the feature representation. Meanwhile, in order to avoid the possible unnatural results caused by the separation of the R, G, B channels, the output of the multi-path interaction network is corrected in detail to obtain the final enhancement results. Experimental results show that the proposed method can effectively improve the visual quality of low-light images, and the performance is better than the state-of-the-art methods.