Artificial light at night (ALAN) is a growing environmental problem influencing the fitness of individuals through effects on their physiology and behaviour. Research on animals has primarily focused on effects on behaviour during the night, whereas less is known about effects transferred to daytime. Here, we investigated in the lab the impact of ALAN on the mating behaviour of an ecologically important freshwater amphipod, Gammarus pulex, during both daytime and nighttime. We manipulated the presence of ALAN and the intensity of male-male competition for access to females, and found the impact of ALAN on mating activity to be stronger during daytime than during nighttime, independent of male-male competition. At night, ALAN only reduced the probability of precopula pair formation, while during the daytime, it both decreased general activity and increased the probability of pair separation after pair formation. Thus, ALAN reduced mating success in G. pulex not only directly, through effects on mating behaviour at night, but also indirectly through a carry-over effect on daytime activity and the ability to remain in precopula. These results emphasise the importance of considering delayed effects of ALAN on organisms, including daytime activities that can be more important fitness determinants than nighttime activities.

Unraveling the mysterious pathways of pollutants to the deepest oceanic realms holds critical importance for assessing the integrity of remote marine ecosystems. This study tracks the transport of pollutants into the depths of the oceans, a key step in protecting the sanctity of these least explored ecosystems. By analyzing hadal trench samples from the Mariana, Mussau, and New Britain trenches, we found the widespread distribution of organophosphate ester (OPE) flame retardants but a complex transport pattern for the OPE in these regions. In the Mariana Trench seawater column, OPE concentrations range between 17.4 and 102 ng L-1, with peaks at depths of 500 and 4000 m, which may be linked to Equatorial Undercurrent and topographic Rossby waves, respectively. Sediments, particularly in Mariana (422 ng g-1 dw), showed high OPE affinity, likely due to organic matter serving as a transport medium, influenced by \"solvent switching\", \"solvent depletion\", and \"filtering processes\". Amphipods in the three trenches had consistent OPE levels (29.1-215 ng g-1 lipid weight), independent of the sediment pollution patterns. The OPEs in these amphipods appeared more linked to surface-dwelling organisms, suggesting the influence of \"solvent depletion\". This study highlights the need for an improved understanding of deep-sea pollutant sources and transport, urging the establishment of protective measures for these remote marine habitats.

For the purpose of sediment quality assessment, the prediction of toxicity risk-levels for aquatic organisms based on simple environmental measurements is desirable. One commonly used approach is the comparison of total contaminant concentrations with corresponding water and sediment quality guideline values, serving as a Line of Evidence (LoE) based on chemistry-toxicity effects relationships. However, the accuracy of toxicity predictions can be improved by considering the factors that modify contaminant bioavailability. In this study we used paired chemistry-ecotoxicity data sets for sediments to evaluate the improvement in toxicity risk predictions using bioavailability-modified guidelines. The sediments were predominantly contaminated with metals, and measurements of sediment particle size, total organic carbon (TOC) and acid volatile sulfide (AVS) were used to modify hazard quotients (HQ). To further assess the predictive efficacy of the bioavailability-modified guideline models, sediments with differing contamination levels were tested for toxicity to a benthic amphipod\'s reproduction. To account for differences between laboratory exposure and field exposure scenarios, where the latter creates greater dilution, both static-renewal and flow-through test procedures were employed, and flow-through resulted in lower dissolved metal concentrations in the overlying waters. We also investigated how lower AVS concentration by oxidation modified the toxicity. This study reaffirmed that consideration of factors that influence contaminant bioavailability improves toxicity risk predictions, however the improvements may be modest. The sediment particle size data had the greatest influence on the modified HQ, indicating that higher percentage of fine particle size (<63 μm) contributed most to a lower predicted toxicity. The comparison of the static-renewal and flow-through test results continue to raise important questions about the relevance of static or static-renewal toxicity test results for risk assessment decisions, as both these test designs may cause unrealistically high contributions of dissolved metals in overlying waters to toxicity. Overall, this study underscores the value of incorporating outcomes from simple and routine sediment analysis (e.g., particle size, TOC, and consideration of AVS) to enhance the predictive efficacy of toxicity risk assessments in the context of sediment quality risk assessment.

A preliminary review of the genus Agalope Walker, 1854 is presented. Two new genera are established for four species-groups: Rotundagalope S.-Y. Huang & Horie, gen. n. (type species Agalope immaculata Leech, 1898, for the immaculata species-group), Paragalope S.-Y. Huang & Horie, gen. n. (type species Chelura pica Wileman, 1910, for the pica, glacialis and dejeani species-groups). An additional new genus, Agacysma S.-Y. Huang & Horie, gen. n., related to Agalope and Elcysma, is erected for the new species Agacysma sinica S.-Y. Huang & Horie sp. n. (mainland China: Chongqing, Hubei & Shaanxi). Two new species of the genus Agalope are described: A. geoffi S.-Y. Huang & Horie sp. n. (mainland China: SE. Xizang) and A. liuzihaoi S.-Y. Huang & Horie sp. n. (mainland China: SE. Xizang), forming a species-group of their own which is clearly different from congeners in their male genitalia. The taxonomic issues between Paragalope haoi (S.-Y. Huang, 2022) comb. n. and P. bieti (Oberthür, 1886) comb. n. are discussed. Moreover, following the erection of Paragalope, the homonymy of Agalope glacialis Butler, 1881 and A. glacialis (Moore, 1872) ends; hence the replacement name of the former, A. butleri Owada & Horie, 2000 syn. n., is unnecessary and hence synonymized. The following new combinations are given: Rotundagalope immaculata (Leech, 1898) comb. nov., Paragalope ardjuna (Roepke, 1936) comb. nov., P. aurelia (Oberthür, 1923) comb. nov., P. basiflava (Moore, 1879b) comb. nov., P. bieti (Oberthür, 1886) comb. nov., P. chayuensis (S.-Y. Huang & Pan, 2022) comb. nov., P. haoi (S.-Y. Huang, 2022) comb. nov., P. owadai (S.-Y. Huang, 2022) comb. nov., P. pica (Wileman, 1910) comb. nov., P. trimacula (Matsumura, 1927) comb. nov., P. wangi (Owada, 1992) comb. nov., P. dejeani (Oberthür, 1893) comb. nov., P. lucia (Oberthür, 1923) comb. nov., P. glacialis glacialis (Moore, 1872) comb. nov., P. glacialis parthenie (Jordan, 1907b) comb. nov., P. glacialis angustifasciata (Hering, 1922) comb. nov., P. glacialis postfasciata (Holloway, 2011) comb. nov. A checklist of the species and genera mentioned in the present study is given. Adults and genitalia of the newly described taxa and related ones are illustrated.

Large numbers of Amphipoda feed on floating green tide macroalgae in the Yellow Sea, among which Ampithoe valida has a high abundance in the stable and decline periods. Amphipoda preferentially feed on Ulva. Under different temperatures, salinities, and pH, the physiological responses of A. valida and its feeding potential on Ulva prolifera were investigated, along with its physiological responses during green tide blooms in the Southern Yellow Sea. Ampithoe valida could survive within a temperature range of 5-30 °C, salinity of 5-40, and pH of 4-10. Optimal environmental conditions for growth were temperature 15-25 °C, salinity 10-40, and pH 6-10. At temperatures of 5-30 °C, salinities of 5-35, and pH of 4-9, A. valida could effectively reduce U. prolifera biomass. The feeding ability of A. valida was greatest in 25-30 °C, 10-25 salinity, and neutral seawater, exceeding 5 mg·ind.-1·d-1. During green tide outbreaks in the Southern Yellow Sea from May to August, the monthly average sea surface temperature, salinity, and pH range is 17.5-27.3 °C, 23.8-29.6, and 7.87-8.17, respectively, within which A. valida showed well growth and could effectively reduce U. prolifera biomass. Finally, this study further discussed the possibility of A. valida as a biological method to control green tide.

Organic anthropogenic pollutants reach even the deepest parts of the oceans, i.e., the hadal trenches. We here presented the concentrations, influencing factors, and potential sources of polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) in hadal sediments and amphipods from the Mariana, Mussau and New Britain trenches. Results showed that BDE 209 was the dominant PBDEs congener and DBDPE was the dominant NBFRs. No significant correlation was found between TOC contents and PBDEs or NBFRs levels in sediment. Lipid content and body length were the potential important factors affecting variation in pollutant concentrations in the carapace & muscle of amphipods, while the pollution levels of viscera were mainly affected by the sex and lipid content. PBDEs and NBFRs might reach trench surface seawater through long-range atmospheric transport and oceans currents but with little contribution from the Great Pacific Garbage Patch. Determination of carbon and nitrogen isotopes indicated that the pollutants were transported and accumulated in amphipods and sediment via different pathways. PBDEs and NBFRs in the hadal sediments were generally transported via the settling of sediment particles of either marine or terrigenous origin whereas in amphipods they accumulated via feeding on animal carrion through the food web. This is the first study reporting on BDE 209 and NBFR contaminations in hadal settings and provide new insight on influencing factors and sources of PBDEs and NBFRs in the deepest oceans.

In this study, we performed a morphometric approach of 23 quantitative features of Paucibranchia bellii (Audouin Milne-Edwards, 1833), P. disjuncta (Hartman, 1961), and P. carrerai Molina-Acevedo, 2018 in order to evaluate their importance in interspecific discrimination. We found that eight of the 23 features measured were correlated with the organisms size, in particular, branchiae, parapodia, and chaetae. The features that were not size-dependent presented a low range of variation related to the maxillary apparatus (as the maxillary formula) or the prostomial appendages and could be used as taxonomically informative characters. The multivariate analysis selected six characteristics that best contributed to the three species discrimination. At least four of these features were related to the start of the branchiae and subacicular hooks, the maximum number of chaetigers with branchiae, and the maximum number of branchial filaments, all of them considered size-dependent. However, two other features, teeth in maxilla III and the length of the opening cavity in the maxillary apparatus, were not size-dependent. The results allowed us to demonstrate that both sized- and non-sized depending on characters are helpful and necessary to improve species discrimination within the genus Paucibranchia. Finally, we provide a detailed analysis of the ontogenetic changes of P. carrerai with additional material found on the east coast of Peninsular Malaysia.

The types and intensity of anthropogenic pressure in the same sea area may differ spatially and may change as time passes, but response of benthic biotic indices to different pressure is different, which makes it unreasonable to use the same benthic biotic indices in a large sea area. We provided a new way of thinking as to selecting benthic biotic indices according to pressure type. The study took six bays under eutrophication and sediment heavy metal pollution to different levels in Fujian coastal water, East China sea, as examples, analysed the response of five benthic biotic indices, namely AZTI marine biotic index (AMBI), multivariate AMBI (M-AMBI), Shannon-Wiener diversity index (H\'), benthic opportunistic polychaetes amphipods (BOPA) and benthic polychaetes amphipods (BPA), to eutrophication factors and sediment heavy metal pollution factors firstly. The result indicated that AMBI well responded to dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP); M-AMBI responded soundly in the range of DIN >0.131 mg L-1 and DIP >0.022 mg L-1 and responded universally to heavy metals; H\' responded to only Hg and Cd; BOPA has response to eutrophication condition of DIN >0.242 mg L-1; BPA had response to DIN, Cu and As. Then, suitable indices were selected based on the four pressure scenarios in the study area. AMBI was selected in no pressure scenario; M-AMBI was chosen under only eutrophication pressure and under dual pressure; H\' was preferred in only heavy metal pressure scenario (mainly Hg pollution). At last, the density plot of the distribution of the selected indices in the evaluation grades under different pressure scenarios proved the proposal of selecting benthic biotic indices according to pressure types feasible. This study can offer some new insights into rapidly choosing indices to evaluate the coastal benthic ecological quality status.

Pesticides from agricultural activities transfer to surrounding waterways, jeopardizing aquatic ecosystem. To better characterize transfer of pesticide residues and toxicity, a batch of pesticides were analyzed in 22 sediment samples collected from the ditches (< 5 m away from field) and receiving streams nearby a vegetable planting area, South China. Sum concentrations of pesticides in ditch sediments (152 ± 121 ng/g dry wt.) were higher than those in stream sediments (24.9 ± 14.9 ng/g dry wt.). Toxicity reduction from ditch to stream was different for two invertebrates. Stream sediment toxicity to Chironomus dilutus decreased considerably but elevated toxicity was still observed (50% mortality on average), while stream sediments exhibited no significant lethality to Hyallela azteca (< 10% mortality). Fipronil and its transformation products (FIPs) were responsible for sediment toxicity to the midges, and pyrethroids contributed significantly to the death of the amphipods. Hydrophobic pyrethroids were tended to stay in the ditches, whereas FIPs were detected in stream sediments at considerable concentrations due their possible transfer to the nearby streams and/or residential use. This physicochemical property-related transfer characteristics and intrinsic toxicity of the major toxicants explained the distinct toxicity reduction patterns for the two species, which highlighted their importance in assessing aquatic transfer and risk of agriculture derived pesticides.

A new species, Gammarus hoboksar Hou, sp. nov., is described from the Irtysh River basin of Xinjiang, China. The species differs morphologically from its congeners by calceoli of antenna II absent; merus and carpus of pereopods IIIIV with short setae; inner ramus of uropod III about 0.79 times the length of outer ramus, terminal article of outer ramus about 0.24 times the length of first article; telson cleft, with spines and setae on surface and three spines on distal end. Phylogenetic analysis based on 28S rRNA and COI gene sequences supported the species distinctness. A key to the genus Gammarus with nine species and a map of their distributions are provided.