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Battulga, B.; Nakayama, Masataka; Matsuoka, Shunsuke*; Kondo, Toshiaki*; Atarashi-Andoh, Mariko; Koarashi, Jun
Water Research, 264, p.122207_1 - 122207_12, 2024/10
Times Cited Count:2 Percentile:61.65(Engineering, Environmental)Growing attention has been given to microbial attachment and biofilm formation on microplastics (MPs; sizes: 5 mm) in the environment. Here, we explore the microbial communities in the plastisphere to improve our understanding of microbial ecology as well as their impacts on aquatic ecosystems. Using the amplicon sequence of 16S and ITS genes, we identified bacterial and fungal community composition and diversity on MPs, surface waters, bottom sediments, and coastal sands in two contrasting coastal areas of Japan. Significantly different microbial diversity and taxonomic composition were detected depending on sample types and research sites. This research highlights the microbial metabolic functions in MP-associated biofilm, which could be the key to uncovering the true impact of plastic debris on the global ecosystem.
Nakayama, Masataka; Abe, Yukiko; Atarashi-Andoh, Mariko; Tange, Takeshi*; Sawada, Haruo*; Liang, N.*; Koarashi, Jun
Applied Soil Ecology, 201, p.105485_1 - 105485_12, 2024/09
Times Cited Count:1 Percentile:0.00(Soil Science)Nitrogen often limits plant growth in forest ecosystems. Plants, including trees, change vertical root distribution when nutrient competition is strong within surface soil layer and take up nitrogen even from subsurface soil layers in addition to the surface soil. However, there is still limited knowledge about nitrogen cycles within deeper soil layers. In this study, we investigated the vertical profiles (0-60 cm) of the net nitrogen mineralization and nitrification rates at four Japanese forest sites with two different soil types (Andosols and Cambisols). The partial least square path modeling (PLS-PM) was used to determine factors affecting nitrogen-cycling processes. The net nitrogen mineralization and nitrification rates per unit soil weight were considerably higher in surface soil layer than in deeper soil layers in Andosols but not in Cambisols. PLS-PM analysis showed that microbial biomass and soil organic matter quantities were the main factors influencing the net nitrogen mineralization and nitrification rates, indicating that a similar mechanism creating the spatial variations of nitrogen-cycling processes in surface soil layer predominantly regulates the processes in subsoil layers. Moreover, it was estimated that the net nitrogen mineralization rate could be comparable at all soil types and depths when the rate was expressed per unit soil volume. Therefore, our results suggest that subsoil layers are a quantitatively important nitrogen source for plant nutrients in Andosols and Cambisols, supporting high forest productivity.
Taniguchi, Takeshi*; Isobe, Kazuo*; Imada, Shogo*; Eltayeb, M. M.*; Akaji, Yasuaki*; Nakayama, Masataka; Allen, M. F.*; Aronson, E. L.*
Science of the Total Environment, 899, p.165524_1 - 165524_13, 2023/11
Times Cited Count:10 Percentile:83.83(Environmental Sciences)Dryland ecosystems experience seasonal cycles of severe drought and moderate precipitation. Desert plants typically have patchy distributions, and many may develop symbiotic relationships with root endophytic microbes to survive under the repeated wet and extremely dry conditions. Although community coalescence has been found in many systems, the colonization by functional microbes and its relationship to seasonal transitions in arid regions are not well understood. Here we examined root endophytic microbial taxa, and their traits in relation to their root colonization, during the dry and wet seasons in a hot desert of the southwestern United States. We used high-throughput DNA sequencing of 16S rRNA and ITS gene profiling of five desert shrubs, and analyzed the seasonal change in endophytic microbial lineages. In summer, Actinobacteria increased, although this was not genus-specific. For fungi, Glomeraceae selectively increased in summer. In winter, Gram-negative bacterial genera, including those capable of nitrogen fixation and plant growth promotion, increased. Neutral model analysis revealed a strong stochastic influence on endophytic bacteria but a weak effect for fungi, especially in summer. The taxa with higher frequency than that predicted by the neutral model shared environmental adaptability and symbiotic traits, whereas the frequency of pathogenic fungi was at or under the predicted value. These results suggest that community assembly of bacteria and fungi is regulated differently. The bacterial community was affected by stochastic and deterministic processes via the bacterial response to drought (response trait) and beneficial effect on plants (effect trait). For fungi, mycorrhizal fungi were selected by plants in summer. The regulation of beneficial microbes by plants in both dry and wet seasons suggests the presence of plant-soil positive feedback in this natural desert ecosystem.
Katata, Genki*; Yamaguchi, Takashi*; Watanabe, Makoto*; Fukushima, Keitaro*; Nakayama, Masataka*; Nagano, Hirohiko*; Koarashi, Jun; Tateno, Ryunosuke*; Kubota, Tomohiro
Atmospheric Environment, 298, p.119640_1 - 119640_12, 2023/04
Times Cited Count:1 Percentile:19.71(Environmental Sciences)Nakayama, Masataka; Tateno, Ryunosuke*
Plant and Soil, 17 Pages, 2023/00
Times Cited Count:2 Percentile:43.10(Agronomy) Microbial communities within the soil surrounding plant roots (rhizosphere) are distinct from those in the non-rhizosphere soil because of root exudation and symbiosis with plant roots and play important roles in plant growth. However, seasonal variations in these rhizosphere microbial communities are not well known, especially during the plant's dormant season in cool temperate forests.
We investigated the rhizosphere microbial communities in a cool-temperate deciduous broad-leaved forest at the growing season (mid-summer) and at the beginning and end of the plant's dormant season (early winter and early spring) using metabarcoding of prokaryotic 16S rRNA genes and fungal ITS region, microbial functional prediction, and co-occurrence network analysis.
The rhizosphere dominant prokaryotic subgroup (occupying 19.4
3.2% of relative read counts) had non-significant seasonal fluctuations, and their relative read counts were correlated with physicochemical properties, including pH and water content. In contrast, the relative read count of ectomycorrhizal fungi was 1.4 times higher in the rhizosphere than that in the bulk soil in mid-summer. However, the relative read counts of ectomycorrhizal fungi within rhizospheres in winter and spring (28.5
18.9% and 20.8
13.8%, respectively) were similar to that in bulk soil (25.8
18.7% and 22.4
17.1%, respectively).
Ectomycorrhizal fungi reduced their occupancy within the rhizosphere during the plant's dormant seasons, whereas rhizosphere-dominant prokaryotic communities were stable during the seasonal change, implying the importance of prokaryotic rather than ectomycorrhizal fungal communities in the processes occurring within the rhizosphere during dormant seasons.
Nagano, Hirohiko; Nakayama, Masataka*; Katata, Genki*; Fukushima, Keitaro*; Yamaguchi, Takashi*; Watanabe, Makoto*; Kondo, Toshiaki*; Atarashi-Andoh, Mariko; Kubota, Tomohiro*; Tateno, Ryunosuke*; et al.
Soil Science and Plant Nutrition, 67(5), p.606 - 616, 2021/10
Times Cited Count:2 Percentile:13.56(Plant Sciences)We analyzed the relationships between nitrogen deposition (deposition of nitrate and ammonium ions) and soil microbial properties in a cool temperate forest surrounded by normally fertilized pasture grasslands in northern Japan. The aim of the present study was to gain the primary information on soil microbial response to moderately elevated nitrogen deposition ( 10 kg N ha
y
). We established three experimental plots in the forest edge adjacent to grasslands and other three plots in the forest interior at least 700 m away from the grasslands. During May to November 2018, nitrogen deposition in each plot was measured. In August 2018, litter and soil (0-5 cm depth) samples were collected from all plots to measure net nitrogen mineralization and nitrification rates as indicators of microbial activity, and microbial biomass carbon and nitrogen and various gene abundances (i.e. bacterial 16S rRNA, fungal ITS, bacterial amoA, and archaeal amoA genes) as indicators of microbial abundance and structure. Nitrogen deposition in the forest edge was 1.4-fold greater than that in the forest interior, even while the maximum deposition was 3.7 kg N ha
. Nitrogen deposition was significantly correlated to the net nitrogen mineralization and nitrification rates and the 16S rRNA and bacterial amoA gene abundances. Microbial community structures were different between litter and soil samples but were similar between the forest edge and interior. Significant correlations of nitrogen deposition to the soil carbon to nitrogen ratio, and the nitrate and ammonium contents were also observed. Thus, our results show that moderately elevated nitrogen deposition in nitrogen-limited forest edges can stimulate microbial activities and abundances in soils.
Ogino, Masataka*; Owaki, Eiji*; Shirase, Mitsuyasu*; Nakayama, Masashi
Konkurito Kogaku Nenji Rombunshu (DVD-ROM), 39(1), p.703 - 708, 2017/07
no abstracts in English
Asahina, Kiyoshi*; Soya, Masataka*; Ogawa, Hikaru*; Akasaka, Takayuki*; Iwata, Toshio*; Fukutome, Yutaka*; Nakayama, Jumpei*
PNC TJ4058 89-005, 178 Pages, 1989/06
None
Nakayama, Masataka; Abe, Yukiko; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Plants take up nitrogen mainly from surface soil, while under the nutrient competition, they utilize nitrogen from subsurface soil layers. However, nitrogen dynamics in the subsoil layer is unclear. Here, we investigated the soil profiles (0-60 cm depth) of net nitrogen mineralization and nitrification rates at four Japanese broad-leave forest having two different soil types (volcanic ash and non-volcanic ash soil). The results showed that net nitrogen mineralization decreased with increase of soil depth in the sites of volcanic ash soil, but the trend was not observed in the sites of non-volcanic ash soil. When the rates represented per unit soil volume, the vertical differences in nitrogen mineralization were non-significant for these two soil types. Similar to the factors regulating the spatial variations of nitrogen dynamics, the vertical trends were regulated by the soil total carbon and nitrogen contents and microbial biomass. These results suggested that the quantities of soil organic material and microbes regulated both of the horizontal and vertical differences in the nitrogen dynamics, and that the subsurface soil, as well as surface soil, was quantitatively important nitrogen source for plants.
Abe, Yukiko; Nakayama, Masataka; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Subsoils contain more than half of the global soil carbon. Decomposition of organic matter accumulated in the subsoil is thought to contribute significantly to heterotrophic respiration, and the supply of new organic matter to the subsoil may accelerate the decomposition of soil organic matter (priming effect). However, the carbon dynamics in the subsoil are unknown. The aim of this study was to evaluate the decomposition response to a new supply of organic matter, focusing on the differences in the interaction between organic matter and minerals in the presence and absence of volcanic ash. The surface and subsoil layers of four study sites with volcanic and non-volcanic ash soils were prepared to 64% of water holding capacity (WHC) and incubated at 20C and 30
C after addition of 1% of WHC or a sucrose solution labeled at
C. Sucrose addition had a positive priming effect in the lower layers of the volcanic ash soils, but the difference in carbon release after 90 days of incubation was about half of the addition in all soils, with and without sucrose addition. Therefore, sucrose addition to the soil enhanced organic matter decomposition, but it was suggested that some of the sucrose may remain in the soil.
Abe, Yukiko; Teramoto, Munemasa*; Nakayama, Masataka; Atarashi-Andoh, Mariko; Liang, N.*; Koarashi, Jun
no journal, ,
Carbon dioxide released from the soil, known as soil respiration, is a major component of the carbon cycle in terrestrial ecosystems, but it is highly spatiotemporally variable. Therefore, observations of soil respiration have been conducted around the world to accurately estimate the total amount of soil respiration, but observations in coastal dune environments are very limited. To quantify the response of soil respiration to climate change, it is necessary to understand soil respiration in different regions and ecosystems and to clarify its controlling factors. The objective of this study was to determine the spatiotemporal variability of soil respiration rates and its controlling factors in coastal dune environments. The study site was a plantation on a coastal dune in the Arid Land Research Center of Tottori University. In June 2023, we established 20 points for soil respiration measurement within the study site and started measuring soil respiration rates. In addition, soil samples were collected every 3 months to measure soil composition. Large spatial variability was observed in soil respiration rates from June to December 2023, with coefficients of variation ranging from 43 to 67%. Seasonal changes in soil respiration rates from June to December 2023 were exponential with increasing soil temperatures, but a temporary decrease was observed in August. Soil respiration rates were positively correlated with WEOC. This suggests that WEOC may contribute to the spatial variability in soil respiration rate in sandy soils with a low organic matter content.
Katata, Genki*; Fukushima, Keitaro*; Koarashi, Jun; Yamaguchi, Takashi*; Watanabe, Makoto*; Nagano, Hirohiko; Nakayama, Masataka*; Tateno, Ryunosuke*; Kinose, Yoshiyuki*
no journal, ,
no abstracts in English
Abe, Yukiko; Nakayama, Masataka; Tange, Takeshi*; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Soil is the largest carbon pool in terrestrial ecosystems, and forest soils in particular play an important role as a C reservoir in the global C cycle. Organic matter in the soil is released to the atmosphere as carbon dioxide through microbial decomposition (heterotrophic respiration). Decomposition of organic matter accumulated in the subsoil may contribute significantly to heterotrophic respiration, but it is not clear. Therefore, the objective of this study was to determine the heterotrophic respiration rate from the surface to the lower layers of forest soils with different parent materials. This presentation will report on the relationship between soil physicochemical and organic matter properties and heterotrophic respiration.
Nagano, Hirohiko*; Nakayama, Masataka; Katata, Genki*; Fukushima, Keitaro*; Yamaguchi, Takashi*; Watanabe, Makoto*; Atarashi-Andoh, Mariko; Tateno, Ryunosuke*; Hiradate, Shuntaro*; Koarashi, Jun
no journal, ,
Battulga, B.; Nakayama, Masataka; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Plastic debris in the aquatic environment has become a growing concern due to their long-term ecological consequences. The current study is focused on microbial community composition on microplastics (MPs; sizes 5 mm) and characteristics of MP-associated biofilms in coastal river environments of Japan in order to understand the impact of MP-associated biofilms on aquatic organic matter cycling. The aims of the current study are i) extraction and characterization of microbial biofilms on MPs and ii) identification of diversity and composition of microbial communities on MP surfaces and in surrounding surface waters and sediments. The samples were collected from two coastal rivers during 2021-2022 on a seasonal basis. In this study, we proposed a new method to extract biofilms from MPs using ultrasound-assisted syringe treatment for isotopic analysis. Morphotypes of MPs and associated specific microbial taxa as well as seasonal differences were also observed.
Suzuki, Yuri*; Nagano, Hirohiko*; Hiradate, Shuntaro*; Atarashi-Andoh, Mariko; Abe, Yukiko; Koarashi, Jun; Nakayama, Masataka
no journal, ,
Suzuki, Yuri*; Nagano, Hirohiko*; Hiradate, Shuntaro*; Atarashi-Andoh, Mariko; Abe, Yukiko; Nakayama, Masataka; Koarashi, Jun
no journal, ,
no abstracts in English
Watanabe, Makoto*; Norisada, Masanari*; Kinose, Yoshiyuki*; Yamaguchi, Takashi*; Nakayama, Masataka*; Fukushima, Keitaro*; Tateno, Ryunosuke*; Nagano, Hirohiko; Koarashi, Jun; Katata, Genki*
no journal, ,
no abstracts in English
Alam, M. M.*; Yamakita, Eri*; Mori, Yuki*; Koarashi, Jun; Atarashi-Andoh, Mariko; Abe, Yukiko; Nakayama, Masataka; Hiradate, Shuntaro*
no journal, ,
Suzuki, Yuri*; Hiradate, Shuntaro*; Koarashi, Jun; Atarashi-Andoh, Mariko; Nakayama, Masataka*; Suzuki, Kazuki*; Abe, Yukiko; Nagano, Hirohiko*
no journal, ,
no abstracts in English