Background:Forest soils in tropical and subtropical areas store a significant amount of carbon.Recent framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SO...Background:Forest soils in tropical and subtropical areas store a significant amount of carbon.Recent framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SOM into particulate and mineral-associated organic matter(POM vs.MAOM)is a promising method for identifying how SOM contributes to reducing global warming.Soil macrofauna,earthworms,and millipedes have been found to play an important role in facilitating SOM processes.However,how these two co-existing macrofaunae impac the litter decomposition process and directly impact the formation of POM and MAOM remains unclear.Methods:Here,we set up a microcosm experiment,which consisted of 20 microcosms with four treatments earthworm and litter addition(E),millipedes and litter addition(M),earthworm,millipedes,and litter addition(E+M),and control(only litter addition)in five replicates.The soil and litter were sterilized prior to beginning the incubation experiment to remove any existing microbes.After incubating the samples for 42 days,the litte properties(mass,C,and N contents),soil physicochemical properties,as well as the C and N contents,and POM and MAOM^(13)C abundance in the 0–5 and 5–10 cm soil layers were measured.Finally,the relative influences o soil physicochemical and microbial properties on the distribution of C and N in the soil fractions were analyzed Results:The litter mass,C,and N associated with all four treatments significantly decreased after incubation especially under treatment E+M(litter mass:-58.8%,litter C:-57.0%,litter N:-75.1%,respectively),while earthworm biomass significantly decreased under treatment E.Earthworm or millipede addition alone showed no significant effects on the organic carbon(OC)and total nitrogen(TN)content in the POM fraction,but join addition of both significantly increased OC and TN regardless of soil depth.Importantly,all three macrofauna treatments increased the OC and TN content and decreased the^(13)C abundance in the MAOM fraction.More than65%of the total variations in the distribution of OC and TN throughout the two fractions can be explained by a combination of soil physicochemical and microbial properties.Changes in the OC distribution in the 0–5 cm soi layer are likely due to a decrease in soil pH and an increase in arbuscular mycorrhizal fungi(AMF),while those in the 5–10 cm layer are probably caused by increases in soil exchangeable Ca and Mg,in addition to fungi and gram-negative(GN)bacteria.The observed TN distribution changes in the 0–5 cm soil likely resulted from a decrease in soil pH and increases in AMF,GN,and gram-negative(GP)bacteria,while TN distribution changes in the 5–10 cm soil could be explained by increases in exchangeable Mg and GN bacteria.Conclusions:The results indicate that the coexistence of earthworms and millipedes can accelerate the litte decomposition process and store more C in the MAOM fractions.This novel finding helps to unlock the processe by which complex SOM systems serve as C sinks in tropical forests and addresses the importance of soil mac rofauna in maintaining C-neutral atmospheric conditions under global climate change.展开更多
Nutrient composition of the manure of four pill millipedes (Arthrosphaera dalyi, ,4. davisoni, ,4. fumosa and,4, magna) inhabiting in semi-evergreen forests and plantations of the Western Ghats of Southwest India wa...Nutrient composition of the manure of four pill millipedes (Arthrosphaera dalyi, ,4. davisoni, ,4. fumosa and,4, magna) inhabiting in semi-evergreen forests and plantations of the Western Ghats of Southwest India was evaluated. The quantity and quality of fecal pellets differed between millipedes and their habitats (forest and plantation). Organic carbon content in manure was lower in plantations than in forests, while nitrogen content was elevated in plantations. The carbon to nitrogen (C/N) ratio of manure was lower in plantations compared to forests. The phosphorus content in manure was elevated in plantations in all except for A. dalyi. Calcium content of manure was increased in plantations than in forests. The contents of magnesium, potassium and phenolics in manure showed varied results. The mass of fecal pellets was correlated only with volume in forests (r=0.882; p 〈0.01) and pH in plantations (r=0.616; p 〈0.05), while the volume of fecal pellets was correlated with nitrogen content in forests (r=0.751; p 〈0.01) and cal- cium in plantations (=0.619; p 〈0.05). The conductivity was positively correlated with phosphorus and potassium, while magnesium was negatively correlated in forests as well as plantations. Potassium and magnesium were negatively correlated in forests (r=0.920; p〈0.001) and plantations (t=0.692; p 〈0.05). Overall, the physicochemical characteristics and nutrient composition of fecal pelets differed between millipedes as well as habitats. The low carbon to nitrogen ratio and the increased nitrogen, phosphorus and calcium content in the manure of millipedes inhabiting in plantations indicates possibilities for successfully employing them for in situ composting of forest or plantation residues.展开更多
Millipede Forming is a novel metal forming method that has been proposed and developed recently.It can be applied to overcome fundamental limitations in conventional roll forming,and,in addition,used for incremental f...Millipede Forming is a novel metal forming method that has been proposed and developed recently.It can be applied to overcome fundamental limitations in conventional roll forming,and,in addition,used for incremental forging and integrated into a strip casting or extrusion process for downstream thickness reduction. In this new method,there are two main principles:①the use of an optimal transitional surface or space linking of the incoming material to the outgoing product,and②implementation of a method to feed the material through the forming device so that it conforms with this ideal space and the required deformation is imposed on it by the tooling. The system described here is called "Millipede forming" because deformation is accomplished in a large number of small steps.A prototype has been built to demonstrate the working principle applied to the replacement of a roll forming process;it can be used to produce simple profiles within a forming length an order of magnitude shorter than the conventional process. In this paper,the working principle of "Millipede forming" is introduced and some fundamental research on forming a channel section and a circular tube is discussed.Following the success of the small scale prototype, research on a full scale pilot machine has been proceeding.It is expected that this process can be developed and extended as a useful alternative to conventional roll forming,incremental forging and within a strip casting or other novel strip material(e.g.nanostructured metals) system.展开更多
We present a comprehensive catalog with an updated database of the fossil record of Diplopoda in the world.Taxonomic data was collected from descriptions and reports published from 1854 to the present.We also include ...We present a comprehensive catalog with an updated database of the fossil record of Diplopoda in the world.Taxonomic data was collected from descriptions and reports published from 1854 to the present.We also include new records from Mexican amber(Upper Oligocene-Lower Miocene),counting 83 unknown fossil inclusions,with the first records of the orders Polyxenida,Platydesmida,and Julida,as well as the families Sphaeriodesmidae and Trichopolydesmidae within Polydesmida.According to our results,Diplopoda counts 413 records featuring 299 distinct taxa ranging from the Middle Silurian to the Upper Pleistocene,representing three subclasses,two subterclasses,six superorders,25 orders,15 superfamilies,55 families,93 genera,and 161 fossil species.To date,no fossils of the order Siphonocryptida have been reported.The fossil record extends over three geological eras:the Paleozoic,with 161 taxa,including 97 species;the Mesozoic,with 53 taxa and 22 species;and the Cenozoic,with 85 taxa and 42 species.The referred material shows different forms of fossil preservation.It comprises 123 impressions,99 compressions,26 ichnites,predominantly from Paleozoic and Mesozoic sediments,and 165 amber inclusions from late Mesozoic and Cenozoic sites.Thus,this catalog allows us to estimate the size and taxonomic composition of Diplopoda in the fossil record worldwide.展开更多
基金supported by the GuangDong Basic and Applied Basic Research Foundation(2022A1515110439)the National Natural Science Foundation of China(32101393)+1 种基金China Postdoctoral Science Foundation(2023M7339832023M743547)。
文摘Background:Forest soils in tropical and subtropical areas store a significant amount of carbon.Recent framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SOM into particulate and mineral-associated organic matter(POM vs.MAOM)is a promising method for identifying how SOM contributes to reducing global warming.Soil macrofauna,earthworms,and millipedes have been found to play an important role in facilitating SOM processes.However,how these two co-existing macrofaunae impac the litter decomposition process and directly impact the formation of POM and MAOM remains unclear.Methods:Here,we set up a microcosm experiment,which consisted of 20 microcosms with four treatments earthworm and litter addition(E),millipedes and litter addition(M),earthworm,millipedes,and litter addition(E+M),and control(only litter addition)in five replicates.The soil and litter were sterilized prior to beginning the incubation experiment to remove any existing microbes.After incubating the samples for 42 days,the litte properties(mass,C,and N contents),soil physicochemical properties,as well as the C and N contents,and POM and MAOM^(13)C abundance in the 0–5 and 5–10 cm soil layers were measured.Finally,the relative influences o soil physicochemical and microbial properties on the distribution of C and N in the soil fractions were analyzed Results:The litter mass,C,and N associated with all four treatments significantly decreased after incubation especially under treatment E+M(litter mass:-58.8%,litter C:-57.0%,litter N:-75.1%,respectively),while earthworm biomass significantly decreased under treatment E.Earthworm or millipede addition alone showed no significant effects on the organic carbon(OC)and total nitrogen(TN)content in the POM fraction,but join addition of both significantly increased OC and TN regardless of soil depth.Importantly,all three macrofauna treatments increased the OC and TN content and decreased the^(13)C abundance in the MAOM fraction.More than65%of the total variations in the distribution of OC and TN throughout the two fractions can be explained by a combination of soil physicochemical and microbial properties.Changes in the OC distribution in the 0–5 cm soi layer are likely due to a decrease in soil pH and an increase in arbuscular mycorrhizal fungi(AMF),while those in the 5–10 cm layer are probably caused by increases in soil exchangeable Ca and Mg,in addition to fungi and gram-negative(GN)bacteria.The observed TN distribution changes in the 0–5 cm soil likely resulted from a decrease in soil pH and increases in AMF,GN,and gram-negative(GP)bacteria,while TN distribution changes in the 5–10 cm soil could be explained by increases in exchangeable Mg and GN bacteria.Conclusions:The results indicate that the coexistence of earthworms and millipedes can accelerate the litte decomposition process and store more C in the MAOM fractions.This novel finding helps to unlock the processe by which complex SOM systems serve as C sinks in tropical forests and addresses the importance of soil mac rofauna in maintaining C-neutral atmospheric conditions under global climate change.
文摘Nutrient composition of the manure of four pill millipedes (Arthrosphaera dalyi, ,4. davisoni, ,4. fumosa and,4, magna) inhabiting in semi-evergreen forests and plantations of the Western Ghats of Southwest India was evaluated. The quantity and quality of fecal pellets differed between millipedes and their habitats (forest and plantation). Organic carbon content in manure was lower in plantations than in forests, while nitrogen content was elevated in plantations. The carbon to nitrogen (C/N) ratio of manure was lower in plantations compared to forests. The phosphorus content in manure was elevated in plantations in all except for A. dalyi. Calcium content of manure was increased in plantations than in forests. The contents of magnesium, potassium and phenolics in manure showed varied results. The mass of fecal pellets was correlated only with volume in forests (r=0.882; p 〈0.01) and pH in plantations (r=0.616; p 〈0.05), while the volume of fecal pellets was correlated with nitrogen content in forests (r=0.751; p 〈0.01) and cal- cium in plantations (=0.619; p 〈0.05). The conductivity was positively correlated with phosphorus and potassium, while magnesium was negatively correlated in forests as well as plantations. Potassium and magnesium were negatively correlated in forests (r=0.920; p〈0.001) and plantations (t=0.692; p 〈0.05). Overall, the physicochemical characteristics and nutrient composition of fecal pelets differed between millipedes as well as habitats. The low carbon to nitrogen ratio and the increased nitrogen, phosphorus and calcium content in the manure of millipedes inhabiting in plantations indicates possibilities for successfully employing them for in situ composting of forest or plantation residues.
文摘Millipede Forming is a novel metal forming method that has been proposed and developed recently.It can be applied to overcome fundamental limitations in conventional roll forming,and,in addition,used for incremental forging and integrated into a strip casting or extrusion process for downstream thickness reduction. In this new method,there are two main principles:①the use of an optimal transitional surface or space linking of the incoming material to the outgoing product,and②implementation of a method to feed the material through the forming device so that it conforms with this ideal space and the required deformation is imposed on it by the tooling. The system described here is called "Millipede forming" because deformation is accomplished in a large number of small steps.A prototype has been built to demonstrate the working principle applied to the replacement of a roll forming process;it can be used to produce simple profiles within a forming length an order of magnitude shorter than the conventional process. In this paper,the working principle of "Millipede forming" is introduced and some fundamental research on forming a channel section and a circular tube is discussed.Following the success of the small scale prototype, research on a full scale pilot machine has been proceeding.It is expected that this process can be developed and extended as a useful alternative to conventional roll forming,incremental forging and within a strip casting or other novel strip material(e.g.nanostructured metals) system.
文摘We present a comprehensive catalog with an updated database of the fossil record of Diplopoda in the world.Taxonomic data was collected from descriptions and reports published from 1854 to the present.We also include new records from Mexican amber(Upper Oligocene-Lower Miocene),counting 83 unknown fossil inclusions,with the first records of the orders Polyxenida,Platydesmida,and Julida,as well as the families Sphaeriodesmidae and Trichopolydesmidae within Polydesmida.According to our results,Diplopoda counts 413 records featuring 299 distinct taxa ranging from the Middle Silurian to the Upper Pleistocene,representing three subclasses,two subterclasses,six superorders,25 orders,15 superfamilies,55 families,93 genera,and 161 fossil species.To date,no fossils of the order Siphonocryptida have been reported.The fossil record extends over three geological eras:the Paleozoic,with 161 taxa,including 97 species;the Mesozoic,with 53 taxa and 22 species;and the Cenozoic,with 85 taxa and 42 species.The referred material shows different forms of fossil preservation.It comprises 123 impressions,99 compressions,26 ichnites,predominantly from Paleozoic and Mesozoic sediments,and 165 amber inclusions from late Mesozoic and Cenozoic sites.Thus,this catalog allows us to estimate the size and taxonomic composition of Diplopoda in the fossil record worldwide.