45 research outputs found

    Reciprocal facilitation between annual plants and burrowing crabs:Implications for the restoration of degraded saltmarshes

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    Increasing evidence shows that facilitative interactions between species play an essential role in coastal wetland ecosystems. However, there is a lack of understanding of how such interactions can be used for restoration purposes in saltmarsh ecosystems. We therefore studied the mechanisms of reciprocal facilitative interactions between native annual plants, Suaeda salsa, and burrowing crabs, Helice tientsinensis, in a middle-elevation saltmarsh (with generally high plant density and moderate tides) in the Yellow River Delta of China. We investigated the relationship between the densities of the plants and crab burrows in different seasons. Then, we tested whether and how saltmarsh plants and crabs indeed facilitate each other in a series of field and laboratory experiments. Finally, we applied the results by creating a field-scale artificial approach for microtopographic modification to restore a degraded saltmarsh. We found that the density of plant seedlings in spring was positively correlated with the density of crab burrows in the previous autumn; moreover, the density of crab burrows was correlated with the density of plants in summer. The concave-convex surface microtopography created by crabs promoted seed retention and seedling establishment of saltmarsh plants in winter and spring. These plants in turn facilitated crabs by inhibiting predators, providing food and reducing physical stresses for crabs in summer and autumn. The experimental removal of saltmarsh plants decreased crab burrow density, while both transplanting and simulating plants in bare patches promoted crabs. The microtopographic modification, inspired by our new understanding of the interactions between saltmarsh plants and crabs, showed that these degraded saltmarsh ecosystems can be restored by a single ploughing intervention. Synthesis. Our results suggest a reciprocal facilitation between annual plants and burrowing crabs in a middle-elevation saltmarsh ecosystem. This knowledge yielded new restoration options for degraded coastal saltmarshes through the one-time ploughing initiation of microtopographic variation, which could promote the re-establishment of ecosystem engineers and lead to the efficient recovery of pioneer coastal vegetation and associated fauna

    An invasive species erodes the performance of coastal wetland protected areas

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    The world has increasingly relied on protected areas (PAs) to rescue highly valued ecosystems from human activities, but whether PAs will fare well with bioinvasions remains unknown. By analyzing three decades of seven of the largest coastal PAs in China, including World Natural Heritage and/or Wetlands of International Importance sites, we show that, although PAs are achieving success in rescuing iconic wetlands and critical shorebird habitats from once widespread reclamation, this success is counteracted by escalating plant invasions. Plant invasions were not only more extensive in PAs than non-PA controls but also undermined PA performance by, without human intervention, irreversibly replacing expansive native wetlands (primarily mudflats) and precluding successional formation of new native marshes. Exotic species are invading PAs globally. This study across large spatiotemporal scales highlights that the consequences of bioinvasions for humanity’s major conservation tool may be more profound, far reaching, and critical for management than currently recognized

    Rosuvastatin Improves Cognitive Function of Chronic Hypertensive Rats by Attenuating White Matter Lesions and Beta-Amyloid Deposits

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    Hypertensive white matter lesion (WML) is one of common causes of vascular cognitive impairment. In this study, we aimed to investigate the effect of rosuvastatin on cognitive impairment and its underlying mechanisms in chronic hypertensive rats. From the 8th week after establishment of stroke-prone renovascular hypertensive rats (RHRSPs), rosuvastatin (10 mg/kg) or saline as a control was administrated once daily for consecutive 12 weeks by gastric gavage. Cognitive function was assessed with the Morris water maze test and novel object recognition test. WML was observed by Luxol fast blue staining. Aβ deposits, Claudin-5, Occludin, and ZO-1 were determined by immunofluorescence. After rosuvastatin treatment, the escape latencies were decreased and the time of crossing the hidden platform was increased in the Morris water maze, compared with the vehicle-treated RHRSP group. In a novel object recognition test, the recognition index in the rosuvastatin-treated RHRSP group was significantly larger than that in the vehicle-treated RHRSP group. Rosuvastatin treatment presented with the effects of lower WML grades, higher expression of tight junction proteins Claudin-5, Occludin, and ZO-1 in the corpus callosum, and less Aβ deposits in the cortex and hippocampus. The data suggested that rosuvastatin improved the cognitive function of chronic hypertensive rats partly by attenuating WML and reducing Aβ burden

    Somatic variants of MAP3K3 are sufficient to cause cerebral and spinal cord cavernous malformations

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    Cerebral cavernous malformations (CCMs) and spinal cord cavernous malformations (SCCMs) are common vascular abnormalities of the central nervous system that can lead to seizure, hemorrhage, and other neurological deficits. Approximately 85% of patients present with sporadic (versus congenital) CCMs. Somatic mutations in MAP3K3 and PIK3CA were recently reported in patients with sporadic CCM, yet it remains unknown whether MAP3K3 mutation is sufficient to induce CCMs. Here we analyzed whole-exome sequencing data for patients with CCM and found that ∼40% of them have a single, specific MAP3K3 mutation (c.1323C\u3eG [p.Ile441Met]) but not any other known mutations in CCM-related genes. We developed a mouse model of CCM with MAP3K3I441M uniquely expressed in the endothelium of the central nervous system. We detected pathological phenotypes similar to those found in patients with MAP3K3I441M. The combination of in vivo imaging and genetic labeling revealed that CCMs were initiated with endothelial expansion followed by disruption of the blood-brain barrier. Experiments with our MAP3K3I441M mouse model demonstrated that CCM can be alleviated by treatment with rapamycin, the mTOR inhibitor. CCM pathogenesis has usually been attributed to acquisition of two or three distinct genetic mutations involving the genes CCM1/2/3 and/or PIK3CA. However, our results demonstrate that a single genetic hit is sufficient to cause CCMs

    Diversity and functional prediction of microbial communities involved in the first aerobic bioreactor of coking wastewater treatment system.

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    The pre-aerobic process of coking wastewater treatment has strong capacity of decarbonization and detoxification, which contribute to the subsequent dinitrogen of non-carbon source/heterotrophic denitrification. The COD removal rate can reach > 90% in the first aerobic bioreactor of the novel O/H/O coking wastewater treatment system during long-term operation. The physico-chemical characteristics of influent and effluent coking wastewater in the first aerobic bioreactor were analyzed to examine how they correlated with bacterial communities. The diversity of the activated sludge microbial community was investigated using a culture-independent molecular approach. The microbial community functional profiling and detailed pathways were predicted from the 16S rRNA gene-sequencing data by the PICRUSt software and the KEGG database. High-throughput MiSeq sequencing results revealed a distinct microbial composition in the activated sludge of the first aerobic bioreactor of the O/H/O system. Proteobacteria, Bacteroidetes, and Chlorobi were the decarbonization and detoxification dominant phyla with the relative abundance of 84.07 ± 5.45, 10.89 ± 6.31, and 2.96 ± 1.12%, respectively. Thiobacillus, Rhodoplanes, Lysobacter, and Leucobacter were the potential major genera involved in the crucial functional pathways related to the degradation of phenols, cyanide, benzoate, and naphthalene. These results indicated that the comprehensive understanding of the structure and function diversity of the microbial community in the bioreactor will be conducive to the optimal coking wastewater treatment

    Microplastic-derived dissolved organic matter and its biogeochemical behaviors in aquatic environments: A review

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    Microplastic-derived dissolved organic matter (MP-DOM) exerts great effects on organic carbon pool and its environmental behaviors in natural waters due to increasing amounts of uncontrolled plastic disposal. However, systematic understanding of chemical composition and environmental impacts of MP-DOM in aquatic systems was limited. In this work, the chemical and molecular structures of MP-DOM derived from diverse characterization methods were examined and synthesized to provide a basis for understanding their environmental processes. Additionally, those factors affecting the quantity and quality of released MP-DOM (e.g., plastic types, water environments, and external weathering conditions) were reviewed. Furthermore, environmental behaviors of MP-DOM including its biological degradation, adsorption on mineral surfaces, and interaction with pollutants, as well as their environmental impacts were comprehensively summarized. Finally, we outlooked the future research directions on MP-DOM studies, aiming to contribute to a deeper understanding of the environmental mechanisms and control of plastic pollution through the analysis of MP-DOM. This review provides information for further understanding the impact of microplastics on natural water, which might have consequences on the fluxes of carbon and biogeochemical behaviors of metal and organic contaminants. The structural features, influence factors, and biogeochemical behavior of MP-DOM were reviewed.Compared with NOM, MP-DOM is dominated by labile aliphatic compounds.UV exposure, high temperature and alkalinity solution could promote MP-DOM release.MP-DOM actively interacts with environmental media and alters their environmental fate. The structural features, influence factors, and biogeochemical behavior of MP-DOM were reviewed. Compared with NOM, MP-DOM is dominated by labile aliphatic compounds. UV exposure, high temperature and alkalinity solution could promote MP-DOM release. MP-DOM actively interacts with environmental media and alters their environmental fate.</p

    Nylon Bristles and Elastomers Retain Centigram Levels of Triclosan and Other Chemicals from Toothpastes: Accumulation and Uncontrolled Release

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    Triclosan (TCS), a broad-spectrum antimicrobial, is used in commercial toothpastes with reported dental benefits. Our studies on 22 popular manual toothbrushes in the U.S. showed that common toothbrush head components can accumulate substantial amounts of TCS after brushing with TCS-formulated toothpastes (TCS-TPs). After simulated 3-month brushing with a commercial best-selling TCS-TP, over one third of the adults’ toothbrushes showed a cumulative TCS uptake of 21–37.5 mg, equivalent to 7–12.5 doses of the TCS used per brushing. Similar results were observed on children’s toothbrushes with small pea-size heads. Elastomer components were found to be the main contributor while both nylon bristles and elastomers could act as absorptive sinks for TCS during brushing. Studies on six different TCS-TPs containing 0.3 wt% TCS showed similar profiles of TCS accumulation. The absorbed TCS was gradually released into toothpaste slurries after switching to TCS-free alternatives. Release of TCS, which typically measured at a fraction (<75%) of the standard dose using the TCS-TPs, continued for over 2 weeks and occurred most rapidly in peroxide-containing “whitening” toothpastes, followed by alkaline and surfactant-rich toothpastes. The accumulating effect was not exclusive to TCS but was commonly observed on several chemicals identified in TCS-TPs and a range of regular toothpastes

    Magnon Torque Transferred into a Magnetic Insulator through an Antiferromagnetic Insulator

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    Electrical spin-orbit torque (SOT) in magnetic insulators (MI) has been intensively studied due to its advantages in spin-orbitronic devices with ultralow energy consumption. However, the magnon torque in the MIs, which has the potential to further lower the energy consumption, still remains elusive. In this work, we demonstrate the efficient magnon torque transferred into an MI through an antiferromagnetic insulator. By fabricating a Pt/NiO/Tm3Fe5O12 heterostructure with different NiO thicknesses, we have systematically investigated the evolution of the transferred magnon torque. We show that the magnon torque efficiency transferred through the NiO into the MI can retain a high value (∼50%), which is comparable to the previous report for the magnon torque transferred into the metallic magnet. Our study manifests the feasibility of realizing the pure magnon-based spin-orbitronic devices with ultralow energy consumption and high efficiency
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