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The Mariana subduction system is an ideal place for ocean–ocean convergence boundary research. As a typical example of an extensional subduction model, the subduction process, subduction mechanism and subduction effect of this system have long been popular research topics. The seismic reflection information of oceanic sedimentary layers shown on multichannel seismic profiles is an intuitive record of small‐ to medium‐scale structural activity and sedimentary sequence evolution and is an important source for studying plate‐coupling processes and tectonic dynamic action. This paper is based on the raw multichannel seismic data of MGL1204 in the Mariana arc forearc region; these data were obtained by using linear interference filter technique noise attenuation technology and multiple velocity iterations to accurately image the oceanic sedimentary layer, and the imagery is used to study the Cenozoic fracture activity and residual strata thickness distribution characteristics of the middle part of the Mariana forearc region and to explore the tectonic migration characteristics of the Cenozoic sedimentary basins. We believe that due to the influence of regional stress field changes caused by the movement directions of the Pacific Plate and Philippine Sea Plate towards the Eurasian Plate, the development of secondary structures in the western Pacific subduction zone shows a characteristic west‐to‐east migration, and the structural characteristics of the Mariana forearc Cenozoic sedimentary basin are consistent with the regional tectonic features. The faults, stratigraphy and depocentres of the oceanic sedimentary layer show a migration pattern from west to east and from north to south overall; 25 and 13 Ma are identified as two key tectonic migration periods, and the tectonic migration characteristics and time records of the basin also provide direct evidence for the plate reconstruction model of trench retreat and Philippine Sea plate rotation. [ABSTRACT FROM AUTHOR]

Phthalic acid esters (PAEs) and carbon nanotubes (CNTs) are common environmental pollutants and may degrade differently with different resulting biotoxicity, when present together. This study investigated the toxicological effects of singular or combined exposure to dibutyl phthalate (DBP) and multi-walled carbon nanotubes (MWCNTs) in KM mice. Results indicated that combined exposure led to slower weight gain and an increased leukocyte count in the blood, as well as liver tissue lesions and downregulation of organ coefficients. Additionally, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were elevated in the liver, and glucose, pyruvate, triglyceride (TG), and total cholesterol (T-CHO) were significantly reduced, suggesting compromised liver function. Furthermore, mRNA levels of genes related to hepatic glucose and lipid metabolism were significantly altered. These findings suggest that combined exposure to DBP and MWCNTs can have severe impacts on liver function in mice, highlighting the importance of considering interactions between multiple contaminants in environmental risk assessments. [ABSTRACT FROM AUTHOR]

Asymmetric competition occurs when some species have distinct advantages over their competitors and is common in animals with overlapping habitats and diet. However, the mechanism allowing coexistence between asymmetric competitors is not fully clear. Chinese white‐bellied rats (Niviventer confucianus, CWR) and Korean field mice (Apodemus peninsulae, KFM) are common asymmetric competitors in shrublands and forests west of Beijing city. They share similar diet (e.g. plant seeds) and activity (nocturnal), but differ in body size (CWR are bigger than KFM), food hoarding habit (CWR: mainly larder hoarding; KFM: both larder and scatter hoarding), and ability to protect cached food (CWR are more aggressive than KFM). Here, we tested seed competition in 15 CWR–KFM pairs over a 10‐day period under semi‐natural enclosure conditions to uncover the differences in food hoarding, cache pilferage, and food protection between the 2 rodents, and discuss the implication for coexistence. Prior to pilferage, CWR harvested and ate more seeds than KFM. CWR tended to larder hoard seeds, whereas KFM preferred to scatter hoard seeds. Following pilferage, CWR increased consumption, decreased intensity of hoarding, and pilfered more caches from KFM than they lost, while KFM increased consumption more than they hoarded, and they preferred to hoard seeds in low and medium competition areas. Accordingly, both of the 2 rodent species increased their total energy consumption and hoarding following pilferage. Both rodent species tended to harvest seeds from the source, rather than pilfer caches from each other to compensate for cache loss via pilferage. Compared to CWR, KFM consumed fewer seeds when considering seed number, but hoarded more seeds when considering the seeds' relative energy (energy of hoarded seeds/rodent body mass2/3) at the end of the trials. These results suggest that asymmetric competition for food exists between CWR and KFM, but differentiation in hoarding behavior could help the subordinate species (i.e. KFM) hoard more energy than the dominant species (i.e. CWR), and may contribute to their coexistence in the field. [ABSTRACT FROM AUTHOR]

One classic system of pulsed resource and animal population is mast seeding and population dynamics of seed‐eating rodents in forests. However, we still lack an understanding of the global patterns regarding the contributions of seed falls to rodent outbreaks or population dynamics. We analyzed a global dataset of coupled long‐term time series of seed abundances and rodent populations from published literature, including 66 and 89 time series (156 rodent–seed pairs from 37 studies) for rodent and seed abundances, respectively. We found only half of the examined rodent populations showed statistically significant coincidence between rodent outbreak and mast‐seeding years. Over all the coupled time series, seed abundance was found to positively correlate with rodent abundance with a one‐year lag, and the relative importance of seed abundance was much lower than that of density dependence in affecting rodent population growth rates. We also found the relative importance of seed abundance decreased, but that of rodent density dependence increased with the latitude of study. For the first time, our work provides a global pattern on the associations between seed falls and rodent population dynamics mostly in mid‐ and high‐latitude forests, and highlights the necessity of more long‐term studies on this subject in more forest ecosystems. [ABSTRACT FROM AUTHOR]

Ambient noise plays a crucial role in influencing the observation quality at seismic stations. By studying the distribution patterns of ambient noise, we can gain initial insights into the noise conditions within a specific research area. This paper investigates the properties of ambient noise in different frequency bands under environmental settings in the Chukchi Sea region, utilizing data collected from ocean bottom seismometers (OBSs) deployed during the Ninth Chinese National Arctic Scientific Survey. The probability density function (PDF) method is used to reveal the distinctive features of ambient noise. In addition, by comparing the crowed number values of ambient noise in the Chukchi Sea area with the global new low-noise model (NLNM) and new high-noise model (NHNM), a more comprehensive understanding of the patterns, distribution characteristics, and sources of ambient noise in the Arctic Chukchi Sea area is gained. The study suggests that the overlying sea ice in the Arctic Chukchi Sea area can suppress the microseismic band ambient noise, and the overall level of ambient noise in the Chukchi Sea area lies between the land seismic ambient noise level and the ambient noise level in the middle- and low-latitude sea areas. Meanwhile, an abnormal power spectrum caused by different levels of natural earthquakes is observed. This study fills the gap by using seafloor seismic instruments to investigate ambient noise in the Chukchi Sea area. [ABSTRACT FROM AUTHOR]

Masting is an evolutionary strategy used by plants to promote seed survival and/or seed dispersal under animal predation, but its effects on seedling establishment in field condition are rarely tested by long‐term experiments incorporating combined effects of seed and animal abundance. Here, we tracked seed production, rodent‐mediated seed dispersal, and seedling establishment in Armeniaca sibirica from 2005 to 2014 in a warm‐temperate forest in northern China, and examined the effects of seed abundance and per capita seed availability on seed fate and seedling recruitment rate. Our results showed that seed abundance or per capita seed availability generally benefited the seedling recruitment of A. sibirica through increasing dispersal intensity, supporting predator dispersal hypothesis. However, seedling recruitment showed satiated or even dome‐shaped association with per capita seed availability, suggesting the benefit to trees would be decreased when seed abundance were too high as compared to rodent abundance (a satiated effect). Our results suggest that the predator dispersal and satiation effects of masting on seedling recruitment can operate together in one system and conditionally change with seed and animal abundance. [ABSTRACT FROM AUTHOR]

Mutualism or antagonism between species is often investigated within the framework of monotonic interactions of either mutualism or antagonism, but studies on transition from mutualism to antagonism (within the context of nonmonotonic interactions) have been largely ignored. In this paper, through a brief review and synthesis, we highlighted the role of mutualism between antagonists in regulating the ecological and evolutionary processes, as well as maintaining the stability and complexity of ecosystems. Mutualism between antagonistic species represents the density‐dependent transition between mutualism and antagonism, which is beneficial to species coexistence and stability of complex ecosystems; thus, it should be favored by natural selection. Species may face selection of conflicting pressure on functional traits in co‐balancing mutualism and antagonism, which may result in evolution of the dual character of species with moderate mutualistic or antagonistic traits. Coevolution and co‐balance of these traits are driving forces in shaping mutualism–antagonism systems. Rewards for mutualists, punishment for exploiters, and competition of meta‐communities are essential in stabilizing mutualism between antagonists. We appeal for more studies on mutualism between antagonists and its ecological and evolutionary implications by expanding the conventional ecological studies from monotonic to nonmonotonic regimes. [ABSTRACT FROM AUTHOR]

Habitat fragmentation results in the loss of seed dispersers and subsequently leads to low regeneration and functional decline of forests. However, very few studies on disperser decline and seedling regeneration have been conducted in urban forest systems. In three isolated forest patches in Wuhan, central China, acorn dispersers, acorn dispersal, acorn deposition patterns in soil seed banks and seedling recruitment of the dominant animal-dispersed tree species (Quercus chenii) were investigated over four consecutive years (2014 to 2017). The hypothesis tested was that the loss of acorn dispersers caused by forest fragmentation leads to low regeneration and functional degradation of the urban forest system. As predicted by the hypothesis, very few acorn dispersers (only a few Chinese white-bellied rats, Niviventer confucianus, and Eurasian jays, Garrulus glandarius, were observed) existed in the forest patches; thus, almost all of the acorns were left on the soil surface under the mother trees, where conditions are not favorable for germination and establishment. Large acorns had higher probabilities of germination and seedling establishment than did small acorns when they were buried in the soil. These results suggest that regeneration of fragmented urban forests is increasingly hampered by sharp reduction in seed disperser abundance. Planting large seeds in the soil may compensate for the low regeneration caused by disperser loss in fragmented urban forests. [ABSTRACT FROM AUTHOR]