23 results on '"Fujio Hyodo"'
Search Results
2. Arbuscular Mycorrhizal Community in Roots and Nitrogen Uptake Patterns of Understory Trees Beneath Ectomycorrhizal and Non-ectomycorrhizal Overstory Trees
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Chikae Tatsumi, Fujio Hyodo, Takeshi Taniguchi, Weiyu Shi, Keisuke Koba, Keitaro Fukushima, Sheng Du, Norikazu Yamanaka, Pamela Templer, and Ryunosuke Tateno
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0106 biological sciences ,mycorrhizal dependence ,dryland ,chemistry.chemical_element ,arbuscular mycorrhizal fungi ,Plant Science ,lcsh:Plant culture ,Biology ,010603 evolutionary biology ,01 natural sciences ,chemistry.chemical_compound ,Nutrient ,15N natural abundance ,Nitrate ,nitrate ,Abundance (ecology) ,Botany ,lcsh:SB1-1110 ,Original Research ,ectomycorrhizal fungi (ECM fungi) ,δ15N ,Understory ,Nitrogen ,chemistry ,Soil water ,Arbuscular mycorrhizal ,010606 plant biology & botany - Abstract
Nitrogen (N) is an essential plant nutrient, and plants can take up N from several sources, including via mycorrhizal fungal associations. The N uptake patterns of understory plants may vary beneath different types of overstory trees, especially through the difference in their type of mycorrhizal association (arbuscular mycorrhizal, AM; or ectomycorrhizal, ECM), because soil mycorrhizal community and N availability differ beneath AM (non-ECM) and ECM overstory trees (e.g., relatively low nitrate content beneath ECM overstory trees). To test this hypothesis, we examined six co-existing AM-symbiotic understory tree species common beneath both AM-symbiotic black locust (non-ECM) and ECM-symbiotic oak trees of dryland forests in China. We measured AM fungal community composition of roots and natural abundance stable isotopic composition of N (δ15N) in plant leaves, roots, and soils. The root mycorrhizal community composition of understory trees did not significantly differ between beneath non-ECM and ECM overstory trees, although some OTUs more frequently appeared beneath non-ECM trees. Understory trees beneath non-ECM overstory trees had similar δ15N values in leaves and soil nitrate, suggesting that they took up most of their nitrogen as nitrate. Beneath ECM overstory trees, understory trees had consistently lower leaf than root δ15N, suggesting they depended on mycorrhizal fungi for N acquisition since mycorrhizal fungi transfer isotopically light N to host plants. Additionally, leaf N concentrations in the understory trees were lower beneath ECM than the non-ECM overstory trees. Our results show that, without large differences in root mycorrhizal community, the N uptake patterns of understory trees vary between beneath different overstory trees.
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- 2021
3. Potential Sources of Ammonium-Nitrogen in the Coastal Groundwater Determined from a Combined Analysis of Nitrogen Isotope, Biological and Geological Parameters, and Land Use
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Mitsuyo Saito, Fujio Hyodo, Sunarya Wibawa, Anna Fadliah Rusydi, Khori Sugianti, Shin-ichi Onodera, and Morihiro Maeda
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lcsh:Hydraulic engineering ,010504 meteorology & atmospheric sciences ,Geography, Planning and Development ,chemistry.chemical_element ,Sewage ,010501 environmental sciences ,Aquatic Science ,engineering.material ,Indramayu ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,lcsh:Water supply for domestic and industrial purposes ,lcsh:TC1-978 ,parasitic diseases ,Ammonium ,sodium ,0105 earth and related environmental sciences ,Water Science and Technology ,lcsh:TD201-500 ,business.industry ,Mineralization (soil science) ,coliform ,ammonium-nitrogen ,Manure ,Nitrogen ,Isotopes of nitrogen ,nitrogen isotope ,chemistry ,Environmental chemistry ,engineering ,Environmental science ,Fertilizer ,business ,alluvial groundwater ,Groundwater - Abstract
The origin of ammonium-nitrogen in Indonesian coastal groundwater has not been intensively examined, meanwhile the elevated concentration remains a concern. This research aims at tracing the potential sources of ammonium-nitrogen in the groundwater of Indramayu, Indonesia where groundwater is vital for livelihood. From results, a combined examination of nitrogen isotope, coliform bacteria, land-use, and geology confirmed the natural and anthropogenic origins of ammonium-nitrogen in the groundwater. In the brackish-water aquaculture region, groundwater has &delta, 15NNH4 values from +1.8 to +4.8&permil, signifying that ammonium-nitrogen is derived from mineralization of organic nitrogen to ammonium. Furthermore, ammonium has a significantly positive relationship with sodium indicating the exchangeable ammonium is mobilized to groundwater via cation exchange. Meanwhile ammonium-nitrogen from anthropogenic waste was detected in agricultural and residential region. The groundwater has more varied &delta, 15NNH4 values, from &minus, 2.9 to +16.1&permil, which implies attenuation of ammonium-nitrogen from several sources namely manure, mineral fertilizer, sewage, and pit latrines. Also, the presence of E. coli confirms the indication of human and animal waste contamination. However, since ammonium has no relationship with sodium, cation exchange is not feasible and ammonium-nitrogen flows into the groundwater from anthropogenic sources along with liquid wastes.
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- 2020
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4. Variations in lignin-derived phenols in sediments of Japanese lakes over the last century and their relation to watershed vegetation
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Soichiro Kusaka, Narumi K. Tsugeki, Seiji Ishida, Kohei Omoto, Hajime Ohtsuki, Wataru Makino, Fujio Hyodo, Jotaro Urabe, Ryoma Hayashi, Naoko Sasaki, and Michinobu Kuwae
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Hydrology ,Total organic carbon ,Watershed ,010504 meteorology & atmospheric sciences ,Vegetation ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,chemistry ,Terrestrial organic matter ,Geochemistry and Petrology ,Environmental chemistry ,Lignin ,Environmental science ,Phenols ,Vegetation Index ,Eutrophication ,0105 earth and related environmental sciences - Abstract
Lignins have been used as a biomarker to explore changes in terrestrial organic matter input into lakes and to investigate past watershed vegetation. Burial of organic carbon (OC) in lake sediments, an important component of the global C cycle, is likely associated with the terrestrial OC input. However, few studies have explored changes in terrestrial C input into lakes in the last century. Furthermore, the relationship between lignin phenol compositions and watershed vegetation remains poorly examined. In this study, we examined changes in OC concentrations, OC mass accumulation rates (MAR), and lignin phenol compositions over the last century in sediments from six lakes in Japan that differ in watershed land-use and vegetation. The sediments were dated using 210 Pb and 137 Cs, and showed increased OC concentrations and MARs in three lowland lakes over the last century. This pattern was not found in three mountain lakes. In one of the lowland lakes, lignin phenol concentrations normalized to OC did not change during the periods with high OC concentrations and MARs. This indicates that not only eutrophication but also enhanced terrestrial OC input could lead to greater burial of OC. The lignin phenol compositions did not show clear trends over the last century in most of the lakes examined. The ratios of syringyl to vanillyl phenols and the lignin phenol vegetation index had significant relationships with proportions of angiosperms in watershed vegetation. These results demonstrate that lignin phenols are useful in inferring recent as well as past changes in lake watershed environments.
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- 2017
5. Volcanic deposits affect soil nitrogen dynamics and fungal–bacterial dominance in temperate forests
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Naoko Tokuchi, Tomohiro Yokobe, and Fujio Hyodo
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geography ,geography.geographical_feature_category ,Soil Science ,04 agricultural and veterinary sciences ,Soil carbon ,complex mixtures ,Microbiology ,Andosol ,chemistry.chemical_compound ,Microbial population biology ,Volcano ,Nitrate ,chemistry ,Environmental chemistry ,Soil water ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Environmental science ,Dominance (ecology) ,Nitrification - Abstract
Volcanic deposits increase soil organic carbon storage. However, little is known about the effect of volcanic deposits on forest soil nitrogen (N) dynamics and microbial communities. We explored gross and net N transformation rates and microbial community structure using a phospholipid fatty acid (PLFA) method across eight forests with soils derived from different parent material in Japan. Volcanic mineral soils had approximately three-fold greater total N and inorganic N contents and gross nitrification, ammonium immobilization, and nitrate immobilization rates that were one order of magnitude higher than in non-volcanic soils. Moreover, volcanic mineral soils had a 1.7-fold lower N turnover rate, which was estimated as net N mineralization rate per soil N. This was likely caused by a higher gross N immobilization rate, potentially due to the mineral traits of volcanic soils. Volcanic mineral soils had approximately four- and three-fold greater microbial biomass-N and bacterial PLFA contents, respectively, and the fungal:bacterial PLFA ratio was lower in volcanic mineral soils than in non-volcanic soils. Microbial community structure, analyzed using non-metric multidimensional scaling, was distinct between volcanic and non-volcanic soils, and was significantly affected by soil characteristics. This study demonstrates that aside from soil carbon storage, volcanic deposits are related to increases in soil N immobilization, N content, bacterial biomass, and N transformation rates in forest ecosystems.
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- 2020
6. Seasonal Effects on Microbial Community Structure and Nitrogen Dynamics in Temperate Forest Soil
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Naoko Tokuchi, Fujio Hyodo, and Tomohiro Yokobe
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0106 biological sciences ,nitrogen dynamics ,chemistry.chemical_element ,Growing season ,Biology ,010603 evolutionary biology ,01 natural sciences ,gross nitrogen transformations ,seasons ,Dormant season ,temperature ,soil microbial communities ,PLFA ,Temperate forest ,Forestry ,04 agricultural and veterinary sciences ,Mineralization (soil science) ,lcsh:QK900-989 ,Nitrogen ,chemistry ,Agronomy ,Microbial population biology ,Soil water ,040103 agronomy & agriculture ,lcsh:Plant ecology ,0401 agriculture, forestry, and fisheries - Abstract
The soil microbial community and nitrogen (N) dynamics change seasonally due to several factors. The microbial community structure (MCS) can regulate N dynamics. However, there is insufficient information on seasonal changes in MCS and the relationship between MCS and N dynamics. We investigated MCS and N dynamics in forest soils with two different fertilities throughout a year. MCS, measured with phospholipid fatty acid (PLFA) analysis, showed a consistent seasonal trend, regardless of the fertility. Microbial indices (particularly the Saturated-/monounsaturated-PLFA ratio; Sat/mono) indicated a major PLFA shift among seasons, with temperature likely the most important factor. The fungal-/bacterial-PLFA ratio in the dormant season (December–April) was approximately 1.3 times greater than in the growing season (June–November). The trend in N dynamics showed that in summer (June–August), the gross N mineralization potential was greater than immobilization, whereas in winter (December–April), immobilization was dominant. The net mineralization potential in the growing season was approximately 1.6 times higher than in the dormant season. Moreover, a relationship was found between Sat/mono and N transformation potentials. We highlight the microbial sensitivity to seasonal dynamics which can be associated with temperature, as well as carbon and N dynamics.
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- 2018
- Full Text
- View/download PDF
7. Variation in nitrogen isotopic composition in the Selenga river watershed, Mongolia
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Noboru Fujita, Fujio Hyodo, Choijilsuren Javzan, Davaadorj Gantomor, Narantsetsegiin Amartuvshin, Reiichiro Ishii, Junko Nishikawa, Ayato Kohzu, Jamsran Tsogtbaatar, Eitaro Wada, Mangaa Enkhtuya, and Izuru Saizen
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chemistry.chemical_classification ,Hydrology ,education.field_of_study ,Watershed ,Ecology ,biology ,Aquatic ecosystem ,Population ,Aquatic Science ,biology.organism_classification ,Population density ,Manure ,chemistry ,Environmental science ,Organic matter ,Ecosystem ,Potamogeton ,education ,Water Science and Technology - Abstract
The stable nitrogen (N) isotope ratio (δ15N) has been used to examine the anthropogenic N input (i.e., septic water, wastewater, and manure) to aquatic ecosystems, because anthropogenic N generally has a δ15N signature distinct from that found in nature. Aquatic organisms and the derived organic matter such as sediments are reported to become increasingly enriched in 15N as the human population density increases in watersheds. However, little is known about the relationship in steppe ecosystems, where the livestock population is greater than that of humans. Here, we conducted a preliminary study in the Selenga river mainstream watershed in Mongolia, which covers an area of approximately 300,000 km2. A multiple regression analysis revealed that the δ15N of the riverine sediment was significantly affected by the human population density and more significantly by livestock population density. The population density, including both humans and livestock, significantly influenced δ15N of the macrophytic Potamogeton spp. The results showed that δ15N of riverine organic matter can be an indicator of the human and livestock population density, which is likely associated with the status of N cycles in livestock-dominated watersheds.
- Published
- 2011
8. A strontium isotope analysis on the relationship between ritual tooth ablation and migration among the Jomon people in Japan
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Minoru Yoneda, Takanori Nakano, Atsushi Ando, Soichiro Kusaka, Kazumichi Katayama, Eriko Ishimaru, Fujio Hyodo, and Takakazu Yumoto
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Archeology ,Population ,Human bone ,Zoology ,chemistry.chemical_element ,Biology ,stomatognathic system ,Human tooth ,medicine ,education ,Isotope analysis ,Mobility ,education.field_of_study ,Strontium ,Enamel paint ,Strontium isotopes ,Tooth enamel ,Archaeology ,Isotopes of strontium ,Jomon period ,stomatognathic diseases ,medicine.anatomical_structure ,chemistry ,Ritual tooth ablation ,visual_art ,visual_art.visual_art_medium ,Hunter-gatherers - Abstract
Distinct patterns can be discerned in the extensive ritual tooth ablation found among the human skeletal remains of the Late–Final Jomon period (ca. 3200–2800 cal BP) in Japan. Based on comparative observations of sex and grave patterns in the skeletal remains, two major patterns in ritual tooth ablation, termed type 4I and type 2C, have been assigned to locals and immigrants, respectively. In order to test this hypothesis, strontium (Sr) isotope ( 87 Sr/ 86 Sr) analyses were performed on human skeletal remains from the Yoshigo shell mound in Aichi Prefecture, central Japan. Plants in the surrounding area were also examined to illustrate the geographic 87 Sr/ 86 Sr distribution. The Sr isotopic variation in human tooth enamel ( 87 Sr/ 86 Sr = 0.70868–0.71028) was greater than that in human bones ( 87 Sr/ 86 Sr = 0.70871–0.70943). Individuals with higher Sr isotope ratios in their tooth enamel than seawater Sr values of 0.7092 can be identified as immigrants (36% of population). The presence of these isotopically identified immigrants between both type 2C and type 4I individuals does not support the previous hypothesis. The intra-population 87 Sr/ 86 Sr distribution of tooth enamel of type 2C individuals showed a significantly higher mean ratio than that of type 4I individuals, suggesting a higher proportion of immigrants among the former.
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- 2009
9. Effect of ecosystem retrogression on stable nitrogen and carbon isotopes of plants, soils and consumer organisms in boreal forest islands
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David A. Wardle and Fujio Hyodo
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Delta ,biology ,Chemistry ,Ecology ,Chronosequence ,fungi ,Organic Chemistry ,biology.organism_classification ,Humus ,Analytical Chemistry ,Nutrient ,Soil retrogression and degradation ,Ecosystem ,Nitrogen cycle ,Spectroscopy ,Pleurozium schreberi - Abstract
In the prolonged absence of catastrophic disturbance, ecosystem retrogression occurs, and this involves increased nutrient limitation, and reduced aboveground and belowground ecosystem processes rates. Little is known about how the nitrogen and carbon stable isotope ratios (delta(15)N and delta(13)C) of plants, soils and consumer organisms respond to retrogression in boreal forests. We investigated a 5000 year chronosequence of forested islands in the boreal zone of northern Sweden, for which the time since lightning-induced wildfire increases with decreasing island size, leading to ecosystem retrogression. For this system, tissue delta(15)N of three abundant plant species (Betula pubescens, Vaccinium myrtillus and Pleurozium schreberi) and humus all increased as retrogression proceeded. This is probably due to enhanced ecosystem inputs of N by biological fixation, and greater dependency of the plants on organic N during retrogression. The delta(13)C of B. pubescens and plant-derived humus also increased during retrogression, probably through nutrient limitation increasing plant physiological stress. Unlike the plants, delta(15)N of invertebrates (lycosid spiders and ants) did not increase during retrogression, probably because of their partial dependence on aquatic-derived prey that had a variable delta(15)N signature. The delta(13)C of the invertebrates increased as retrogression proceeded and converged towards that of an aquatic prey source (chironomid flies), suggesting increased dependence on aquatic-derived prey during retrogression. These results show that measurement of delta(15)N and delta(13)C of plants, soils, and consumers across the same environmental gradient can provide insights into environmental factors that drive both the aboveground and belowground subsystems, as well as the linkages between them.
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- 2009
10. Use of Stable Nitrogen Isotope Signatures of Riparian Macrophytes As an Indicator of Anthropogenic N Inputs to River Ecosystems
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Takanori Nakano, Noboru Fujita, Toshi Nagata, Fujio Hyodo, Toshihiro Miyajima, Kiyoshi Matsui, Chikage Yoshimizu, Ayato Kohzu, Ichiro Tayasu, and Eitaro Wada
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River ecosystem ,Nitrogen ,chemistry.chemical_compound ,Japan ,Rivers ,Nitrate ,Humans ,Environmental Chemistry ,Ecosystem ,Riparian zone ,Hydrology ,geography ,Nitrates ,geography.geographical_feature_category ,Nitrogen Isotopes ,Land use ,Aquatic ecosystem ,Water ,General Chemistry ,Plants ,Macrophyte ,chemistry ,Environmental science ,Seasons ,Surface water - Abstract
Deterioration of aquatic ecosystems resulting from enhanced anthropogenic N loading has become an issue of increasing concern worldwide, and methods are needed to trace sources of N in rivers. Because nitrate from sewage is enriched in 15N relative to nitrate from natural soils, delta(15)N values of stream nitrate (delta(15)Nnitrate) should be an appropriate index of anthropogenic N loading to rivers, as should the delta(15)N values of riparian plants (delta(15)Nplant) because they are consumers of nitrate. We determined the delta(15)N values of stream nitrate and six species of riparian macrophytes in 31 rivers in the Lake Biwa Basin in Japan. We then tested the correlation between these values and various land-use parameters, including the percentage of land used for residential and agricultural purposes as well as for natural areas. These delta(15)N values were significantly positively correlated with land use (%) that had a high N load (i.e., residential or agricultural use) and significantly negatively correlated with forest (%). These findings indicate that delta(15)N values of stream nitrate and riparian plants might be good indicators of anthropogenic inputs of nitrogen.
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- 2008
11. Changes in stable isotopes, lignin-derived phenols, and fossil pigments in sediments of Lake Biwa, Japan: Implications for anthropogenic effects over the last 100 years
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Masami Nakanishi, Narumi K. Tsugeki, Eitaro Wada, Fujio Hyodo, Jotaro Urabe, and Jun-ichi Azuma
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Geologic Sediments ,Environmental Engineering ,ved/biology.organism_classification_rank.species ,Fresh Water ,Lignin ,Suess effect ,Japan ,Phenols ,Terrestrial plant ,Humans ,Environmental Chemistry ,Human Activities ,Organic matter ,Ecosystem ,Coloring Agents ,Waste Management and Disposal ,Isotope analysis ,chemistry.chemical_classification ,Carbon Isotopes ,Nitrogen Isotopes ,Fossils ,ved/biology ,Ecology ,Stable isotope ratio ,Carbon-13 ,Eutrophication ,Pollution ,chemistry ,Environmental chemistry - Abstract
We measured stable nitrogen (N) and carbon (C) isotope ratios, lignin-derived phenols, and fossil pigments in sediments of known ages to elucidate the historical changes in the ecosystem status of Lake Biwa, Japan, over the last 100 years. Stable N isotope ratios and algal pigments in the sediments increased rapidly from the early 1960s to the 1980s, and then remained relatively constant, indicating that eutrophication occurred in the early 1960s but ceased in the 1980s. Stable C isotope ratios of the sediment increased from the 1960s, but decreased after the 1980s to the present. This decrease in stable C isotope ratios after the 1980s could not be explained by annual changes in either terrestrial input or algal production. However, when the C isotope ratios were corrected for the Suess effect, the shift to more negative isotopic value in atmospheric CO 2 by fossil fuel burning, the isotopic value showed a trend, which is consistent with the other biomarkers and the monitoring data. The trend was also mirrored by the relative abundance of lignin-derived phenols, a unique organic tracer of material that originated from terrestrial plants, which decreased in the early 1960s and recovered to some degree in the 1980s. We detected no notable difference in the composition of lignin phenols, suggesting that the terrestrial plant composition did not change markedly. However, we found that lignin accumulation rate increased around the 1980s. These results suggest that although eutrophication has stabilized since the 1980s, allochthonous organic matter input has changed in Lake Biwa over the past 25 years.
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- 2008
12. Nitrogen-stable isotopic signatures of basal food items, primary consumers and omnivores in rivers with different levels of human impact
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Kiyoshi Matsui, Fujio Hyodo, Ichiro Tayasu, Eitaro Wada, Akitake Igeta, Chikage Yoshimizu, Yukihiro Kohmatsu, Toshi Nagata, Yukio Onoda, Ayato Kohzu, Yasuhiro Takemon, Takanori Nakano, and Atsushi Maruyama
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chemistry.chemical_classification ,Primary (chemistry) ,Ecology ,chemistry.chemical_element ,δ15N ,Biology ,Nitrogen ,Food web ,Basal (phylogenetics) ,Nutrient ,Benthos ,chemistry ,Benthic zone ,Organic matter ,Omnivore ,Ecology, Evolution, Behavior and Systematics ,Trophic level - Abstract
We examined how nitrogen-stable isotopic signatures of food web components (basal resources, primary and lower consumers, and omnivores) in rivers change with increasing levels of human population density (HPD) in their watersheds. Samples were collected from 22 rivers flowing in the Lake Biwa basin, Japan. Among three potential resources at the base of food webs (epilithon, benthic and suspended particulate organic matter), the mean isotopic values (δ15N) of the epilithon (4.5–7.8%) were consistently higher than those of other items (1.9–4.2%) and displayed the most pronounced elevation (by 3.3%) with increasing HPD. The mean δ15N values of the individual taxa of lower consumers (bivalve, snail and caddisfly) tended to increase with increasing HPD, although the pattern and the extent of the elevation were highly variable among the taxa. These results suggest a taxon-specific feature in the N source (or sources) of lower consumers. Our data suggested that human activities (e.g. nutrient loading) potentially induce changes in the N baselines of river food webs. The major N source of bivalves appeared to be shifted from suspended particulate organic matter to other items with increasing HPD. Trophic levels of goby fish (Rhinogobius sp. OR) and shrimp (Palaemon paucidens), being estimated to be at 2.4–3.8 and 2.1–3.4, respectively, did not differ significantly among rivers with different HPD levels.
- Published
- 2008
13. The feeding habits of collembola along decomposition gradients using stable carbon and nitrogen isotope analyses
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Takuo Hishi, Hiroshi Takeda, Fujio Hyodo, and Seikoh Saitoh
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geography ,geography.geographical_feature_category ,Chemistry ,Ecology ,Meiobenthos ,Fauna ,Soil Science ,Microbiology ,Decomposition ,Isotopes of nitrogen ,Isotopic signature ,Isotopes of carbon ,Temperate coniferous forest ,Isotope analysis - Abstract
We measured the natural stable carbon (C) and nitrogen (N) isotope ratio patterns of collembola and the organic substrates of their habitats and potential food sources in a warm temperate coniferous forest. Based on previous studies, we classified collembola into successional classes along litter decomposition gradients: early colonizers, late colonizers, and dominants-throughout. The stable C and N isotope ratios of late colonizers exceeded those of early colonizers, and those of the dominants-throughout were intermediate between early and late colonizers, which is consistent with previous studies on two macro-invertebrates, earthworms and termites. The C and N isotopic signature differences in collembola may reflect food resource partitioning along decomposition gradients.
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- 2007
14. Estimation of the longevity of C in terrestrial detrital food webs using radiocarbon (14C): how old are diets in termites?
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E. Wada, Ichiro Tayasu, and Fujio Hyodo
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chemistry.chemical_classification ,Primary producers ,Ecology ,Biology ,biology.organism_classification ,Food web ,law.invention ,Animal science ,chemistry ,law ,Grazing ,Terrestrial ecosystem ,Organic matter ,Radiocarbon dating ,Ecology, Evolution, Behavior and Systematics ,Trophic level ,Apis florea - Abstract
Summary 1We propose that diets of consumers in a food web have various ages, where age is defined as the time elapsed since carbon (C) in the diet was fixed from atmospheric CO2 by primary producers. To examine the diet ages for primary consumers in a detrital food web, we measured the radiocarbon (14C) content of termites collected in Thailand in 1998 and 2004. Diet ages were estimated by comparing the 14C content of samples with records of atmospheric 14CO2, which doubled in the early 1960s as a result of nuclear weapons tests and decreased after the nuclear test ban treaty. For comparison, we measured the 14C content of bees as primary consumers in a grazing web at the same study site. Stable carbon and nitrogen (N) isotope ratios were also analysed. 2The 14C contents of the same species of termites decreased during the sampling interval, indicating that they used organic matter produced after the peak in atmospheric 14CO2. The diet ages were estimated to be 12–18, 7–13 and 5–9 years for the wood-feeder (Microcerotermes crassus), the soil-feeders (Dicuspiditermes makhamensis and Termes comis) and the fungus-grower (Macrotermes carbonarius), respectively. One colony of soil-feeder (T. comis), which nested in a fallen tree trunk, had exceptionally low 14C content, and its diet age was estimated to be around 50 years. The two bee species had lower 14C contents compared with the termites, and their diet ages were estimated to be 0 (Apis florea) and 2–4 years (Trigona sp.). 3Stable C and N isotope ratios of termites showed similar patterns as previously reported, and no clear difference was observed between 1998 and 2004. Although the bees and the fungus-growing termite had similar stable C and N isotope ratios, their diet ages differed. 4Our study suggests that radiocarbon can be used to estimate the diet ages of consumers in terrestrial food webs. Diet age should provide new insight into the trophic positions of organisms in grazing and detrital food webs and the interactions between these two webs.
- Published
- 2006
15. Sulfur and strontium isotope geochemistry of tributary rivers of Lake Biwa: implications for human impact on the decadal change of lake water quality
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Takanori Nakano, Akitake Igeta, Fujio Hyodo, Eitaro Wada, Yuuta Miura, and Ichiro Tayasu
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Geologic Sediments ,Geological Phenomena ,Environmental Engineering ,Watershed ,chemistry.chemical_element ,Fresh Water ,Strontium Isotopes ,Japan ,Rivers ,Water Supply ,Sulfur Isotopes ,Tributary ,Environmental Chemistry ,Human Activities ,Water pollution ,Waste Management and Disposal ,Isotope analysis ,Hydrology ,geography ,Strontium ,geography.geographical_feature_category ,Geology ,Pollution ,Isotopes of strontium ,chemistry ,Environmental science ,Water quality ,Surface water ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
To study the deterioration of the water quality in Lake Biwa, Japan, over the last 40 years, we measured the concentrations and isotopic ratios of sulfur and strontium of water in 41 inflowing rivers and one discharging river. The concentrations of SO4 and Sr of inflowing rivers at downstream sites were generally high in the southern urban area and in the eastern area, where a large agricultural plain is situated, but low in the northern and western areas, whose watersheds are mountainous and with low population density. SO4 and Sr concentrations are also lower at upstream sites, which are closer to mountainous areas. Thus, the inflowing river receives large amounts of SO4 and Sr as it flows across the plain, where human activity levels are high. The delta34S or 87Sr/86Sr values of most eastern rivers at downstream sites are lower than those of water in Lake Biwa, and values become more uniform as the proportion of the plain area in the watershed increases. River water in other areas has higher values of delta34S or 87Sr/86Sr than the lake water. This result indicates that the decadal decrease of delta34S and 87Sr/86Sr in the lake water has been caused mainly by the increased flux of SO4 and Sr from rivers in the eastern plain. We assume that in the plain, sulfur, nitrogen, and organic compounds induced by human activities generate sulfuric, nitric, and organic acids in the water, which accelerate the extraction of Sr from bedrocks, leading to the generation of Sr in the river water in the area.
- Published
- 2005
16. Differential role of symbiotic fungi in lignin degradation and food provision for fungus-growing termites (Macrotermitinae: Isoptera)
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Fujio Hyodo, Ichiro Tayasu, Toshiaki Kudo, J.‐I. Azuma, Takuya Abe, and Tetsushi Inoue
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food.ingredient ,biology ,fungi ,Fungus ,biology.organism_classification ,Conidium ,chemistry.chemical_compound ,Lignin degradation ,food ,chemistry ,Termitomyces ,Botany ,Macrotermes ,Lignin ,Cellulose ,Macrotermitinae ,Ecology, Evolution, Behavior and Systematics - Abstract
Summary 1To investigate whether the role of symbiotic fungi in lignin degradation and food provision differs among fungus-growing termites (four species of Macrotermes, three species of Odontotermes, Hypotermes makhamensis, Ancistrotermes pakistanicus and Pseudacanthotermes militaris), the chemical composition of fungus combs of different ages and the chitinolytic activity in the gut of termites were analysed. In addition, the carbon stable isotope ratios (δ13C) in old combs, worker termite tissues and fungal nodules (aggregated conidia) were compared. 2In Macrotermes spp., the carbohydrate : lignin ratio of the combs increased with increased comb age, but it decreased or remained the same in Odontotermes spp., H. makhamensis, A. pakistanicus and P. militaris. In contrast, the chitin : carbohydrate ratio and ash content increased more over time in the combs of Odontotermes spp., H. makhamensis, A. pakistanicus and P. militaris than in the combs of Macrotermes spp. 3Chitinolytic activity in the gut of workers was higher in O. takensis, H. makhamensis and A. pakistanicus than in M. annandalei. 4In all species examined, the δ13C value increased in the sequence: old combs < termites < fungal nodules. Based on a two-source model of δ13C, the contribution of fungi to termite nutrition was considered higher in Odontotermes spp., H. makhamensis, A. pakistanicus and P. militaris than in Macrotermes spp. 5These results suggest that symbiotic fungi play different roles among fungus-growing termites. In Macrotermes spp., the main role of symbiotic fungi is to degrade lignin, so that the termites can utilize cellulose more efficiently, whereas in Odontotermes spp., H. makhamensis, A. pakistanicus and P. militaris, it is to serve as a food source.
- Published
- 2003
17. Caste-specific N and C isotope ratios in fungus-growing termites with special reference to uric acid preservation and their nutritional interpretation
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Ichiro Tayasu, Takuya Abe, and Fujio Hyodo
- Subjects
food.ingredient ,Ecology ,biology ,δ13C ,Fungus ,biology.organism_classification ,Isotopes of nitrogen ,chemistry.chemical_compound ,Termitidae ,Animal science ,food ,chemistry ,Isotopes of carbon ,Insect Science ,Botany ,Macrotermes ,Uric acid ,Macrotermitinae - Abstract
1. Nitrogen and carbon isotope ratios and uric acid concentrations in fungus-growing termites (Isoptera: Termitidae: Macrotermitinae), sampled in Cameroon and Thailand, were determined in order to compare castes that are known to differ in behaviour and feeding habits. 2. Nitrogen isotope ratios (δ15N) were either not significantly changed or lower in workers compared with the diet (the fungus combs), whereas carbon isotope ratios (δ13C) were higher in worker termites than in the fungus combs. 3. In old workers, δ15N values were unexpectedly low and correlated negatively with whole-body uric acid concentrations. This indicates that older workers retain uric acid, which has a low δ15N value, to conserve nitrogen within the colony and, furthermore, that older colony members may ultimately be consumed by younger conspecifics.
- Published
- 2002
18. Nitrogen and carbon stable isotope ratios in the sympatric Australian termites, Amitermes laurensis and Drepanotermes rubriceps (Isoptera: Termitidae) in relation to their feeding habits and the quality of their food materials
- Author
-
Fujio Hyodo, Takuya Abe, Tetsushi Inoue, Alister V. Spain, and Ichiro Tayasu
- Subjects
Stable isotope ratio ,Soil Science ,chemistry.chemical_element ,Biology ,biology.organism_classification ,Microbiology ,Nitrogen ,chemistry.chemical_compound ,Termitidae ,chemistry ,Habitat ,Sympatric speciation ,Botany ,Lignin ,Drepanotermes rubriceps ,Carbon - Abstract
Tissue N and C stable isotope ratios of two sympatric termite species were investigated in relation to those of their stored food materials at two savanna sites in north-eastern Australia (Woodstock and Oak Valley). At both sites, the δ 15 N values of termite tissues and the stored food materials of the litter-feeding species Amitermes laurensis were significantly greater than their equivalents in the grass-harvesting species Drepanotermes rubriceps . In addition, the carbohydrate/lignin and C/N ratios were higher and chitin/carbohydrate ratios were lower in food materials stored in the mounds of D. rubriceps . Both sets of analyses confirmed that D. rubriceps assimilates less decomposed food materials than A. laurensis . Tissue δ 13 C values indicated that both species assimilated similar proportions of C3 and C4 plant materials at the Woodstock site, but that the workers of A. laurensis assimilated a greater proportion of C3 plant material at the Oak Valley site. The δ 15 N values of termites from the Woodstock site were significantly greater than those from Oak Valley, although the differences in order at each site were consistent between species. The results indicate that N and C stable isotope ratios must be carefully compared across habitats.
- Published
- 2002
19. Termite ecology in a dry evergreen forest in Thailand in terms of stable (δ13C andδ15N) and radio (14C,137Cs and210Pb) isotopes
- Author
-
Toshio Nakamura, Fujio Hyodo, Hirotaka Oda, Ichiro Tayasu, Yoko Takematsu, and Takuya Abe
- Subjects
chemistry.chemical_classification ,biology ,δ13C ,Ecology ,Tropics ,δ15N ,biology.organism_classification ,Evergreen forest ,Termitidae ,Nest ,chemistry ,Organic matter ,Ecosystem ,Ecology, Evolution, Behavior and Systematics - Abstract
Stable (δ13C and δ15N) and radio- (14C, 137Cs and 210Pb) isotopes were determined for termites that have been sampled from a dry evergreen forest in Thailand. A wood-feeding termite, Microcerotermes crassus, was separated from soil-feeders: Termes propinquus, Termes comis and Dicuspiditermes makhamensis by δ13C and δ15N values. The Termes group in Thailand had less diverse values in δ13C and δ15N than those in Australia, where the feeding habits of the ‘Termes’ group are more diverse. Other soil-feeding termites produced similar δ13C values, but a larger range in δ15N values. 14C-percent modern carbon (pMC) values suggest that the soil-feeding termites used younger carbon than the wood-feeding termites, and this was consistent with the termites from Cameroon, central Africa. Values of δ13C and 14C-pMC indicate that surface soil was used by a soil-feeding termite, D. makhamensis, in making the nest mounds, and deeper soil (10–30 cm) by a fungus-growing termite, Macrotermes carbonarius. 210Pb and 137Cs were scarcely incorporated into the termites, although 214Pb was recovered from the workers. The results suggest that stable- and radioisotopes are useful in the study of detritivorous animals, organic matter decomposition and ecosystem engineering.
- Published
- 2002
20. Role of the mutualistic fungus in lignin degradation in the fungus-growing termite Macrotermes gilvus (Isoptera; Macrotermitinae)
- Author
-
Takuya Abe, Ichiro Tayasu, Tetsushi Inoue, Fujio Hyodo, and J.‐I. Azuma
- Subjects
biology ,fungi ,Soil Science ,Macrotermes gilvus ,Fungus ,biology.organism_classification ,Microbiology ,chemistry.chemical_compound ,Termitidae ,chemistry ,Symbiosis ,Termitomyces ,Botany ,Lignin ,Cellulose ,Macrotermitinae - Abstract
In order to investigate the role of the mutualistic fungus, Termitomyces sp., in the fungus-growing termite, Macrotermes gilvus , we applied CP/MAS 13 C NMR and selected proximate analyses to fungus comb of different ages and degrees of maturation. We found evidence that lignin degradation took place progressively in the fungus comb. In vitro digestibility of cellulose in old fungus comb, on which the termites feed, was approximately 3-fold higher than that in the fresh part. These results confirm the ‘lignin degradation hypothesis’ that the role of the mutualistic fungi is to degrade lignin and enhance the digestibility of cellulose for the termites, suggesting the ability of the termite–fungus association to make extremely efficient use of plant material.
- Published
- 2000
21. Estimation of Effect of Passage Through the Gut of a Lower Termite, Coptotermes formosanus Shiraki, on Lignin by Solid-State CP/MAS 13C NMR
- Author
-
Fujio Hyodo, Takuya Abe, and Jun-ichi Azuma
- Subjects
Biomaterials ,chemistry.chemical_compound ,biology ,Biochemistry ,Coptotermes ,chemistry ,Solid-state ,Lignin ,Organic chemistry ,Carbon-13 NMR ,Digestion ,biology.organism_classification ,Rhinotermitidae - Published
- 1999
22. Gradual enrichment of N-15 with humification of diets in a below-ground food web : relationship between N-15 and diet age determined using C-14
- Author
-
Patrick Lavelle, Souleymane Konaté, Jérôme E. Tondoh, Ichiro Tayasu, Fujio Hyodo, E. Wada, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)
- Subjects
0106 biological sciences ,stable nitrogen isotope ,termites ,earthworms ,Photosynthesis ,010603 evolutionary biology ,01 natural sciences ,Animal science ,Botany ,Organic matter ,Ecology, Evolution, Behavior and Systematics ,Trophic level ,2. Zero hunger ,chemistry.chemical_classification ,biology ,Soil organic matter ,Earthworm ,04 agricultural and veterinary sciences ,15. Life on land ,biology.organism_classification ,Humus ,Food web ,chemistry ,13. Climate action ,040103 agronomy & agriculture ,radiocarbon ,0401 agriculture, forestry, and fisheries ,Epigeal ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology - Abstract
1. Stable nitrogen (N) isotope has been widely used to disentangle food webs and to infer trophic positions of organisms based on an assumption that the stepwise enrichment occurs along trophic levels. The enrichment of N-15 in soil organisms with diet humification has also been reported, but the underlying mechanism has not been fully examined. 2. To examine the effect of diet humification on N-15, we estimated the stable N isotope ratios and diet ages of earthworms and termites. These organisms feed on organic matter with various degrees of humification, ranging from undecomposed plant materials to humified organic matter (soil organic matter), in a gallery forest and a savanna in the Ivory Coast. We defined diet age as the time elapsed since carbon (C) in the diet of earthworms and termites was fixed from atmospheric CO2 by photosynthesis; it was estimated by comparing the radiocarbon (C-14) content of these organisms to atmospheric (CO2)-C-14 records. 3. Stable N isotope ratios increased along the humification gradient of diets, and values for earthworms and termites varied from 1.8 parts per thousand to 9.9 parts per thousand and from -1.5 parts per thousand to 15.9 parts per thousand, respectively. Epigeic (litter-feeding) earthworms had younger diet ages (2-4 years), whereas endogeic (soil-feeding) earthworms generally exhibited older diet ages (5-9 years). Grass-feeding termites had young diet ages (2 years), and wood/soil-feeding termites had the oldest diet ages (c. 50 years). Soil-feeding termites were similar in diet age (7-12 years) to wood feeders (8-11 years), with the exception of one species (18-21 years) that consumes large-diameter wood. 4. A significant positive relationship was found between diet ages and stable N isotope ratios of the two groups in the savanna. This relationship held in the gallery forest when termites feeding on woody tissues were not considered. These results show that the stable N isotope ratios of organisms can increase with diet age, unless C in the diet has been stored as organic matter, such as woody tissue, that is able to age without being subject to humification processes. 5. Given that above-ground food webs are often sustained directly by material and energy flow from below-ground food webs, in addition to trophic interactions, gradual enrichment of N-15 with the humification of below-ground diets should be considered when interpreting stable N isotope ratios of terrestrial food webs.
- Published
- 2008
23. Stable isotope ratios and uric acid preservation in termites belonging to three feeding habits in Thailand
- Author
-
N. Kirtibutr, Ichiro Tayasu, Fujio Hyodo, Atsuko Sugimoto, Tetsushi Inoue, Yoko Takematsu, and Takuya Abe
- Subjects
Dicuspiditermes makhamensis ,Lichens ,chemistry.chemical_element ,Isoptera ,Trees ,Inorganic Chemistry ,chemistry.chemical_compound ,Soil ,Animal science ,Environmental Chemistry ,Animals ,Lichen ,General Environmental Science ,Carbon Isotopes ,Nitrogen Isotopes ,Ecology ,Chemistry ,Stable isotope ratio ,Microcerotermes crassus ,Carbon-13 ,Significant difference ,Feeding Behavior ,Thailand ,Nitrogen ,Wood ,Uric Acid ,Uric acid - Abstract
Nitrogen and carbon stable isotope ratios and uric acid concentrations in termites sampled from a dry evergreen forest in Thailand, were determined across three kinds of feeding habits. Feeding habits of Microcerotermes crassus, which is an abundant wood-feeder, and Dicuspiditermes makhamensis, a common soil-feeding termite, were confirmed by isotopic signatures. Lichen feeding termites (Hospitalitermes birmanicus, H. bicolor and H. ataramensis) were characterized by low delta15N values, suggesting that they assimilated nitrogen deposited from the atmosphere. There was also a significant difference in uric acid concentrations between termites representing different feeding habits. No significant relationships were found between uric acid concentrations and delta15N or delta13C in Hospitalitermes. However, delta15N values were correlated with C/N ratios in H. birmanicus, except in one colony of H. ataramensis. delta13C values in both species were negatively correlated with C/N ratios.
- Published
- 2001
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