Evolutionary Divergences in Root Exudate Composition among Ecologically-Contrasting Helianthus Species.

PubMed

Bowsher, Alan W; Ali, Rifhat; Harding, Scott A; Tsai, Chung-Jui; Donovan, Lisa A

2016-01-01

Plant roots exude numerous metabolites into the soil that influence nutrient availability. Although root exudate composition is hypothesized to be under selection in low fertility soils, few studies have tested this hypothesis in a phylogenetic framework. In this study, we examined root exudates of three pairs of Helianthus species chosen as phylogenetically-independent contrasts with respect to native soil nutrient availability. Under controlled environmental conditions, seedlings were grown to the three-leaf-pair stage, then transferred to either high or low nutrient treatments. After five days of nutrient treatments, we used gas chromatography-mass spectrometry for analysis of root exudates, and detected 37 metabolites across species. When compared in the high nutrient treatment, species native to low nutrient soils exhibited overall higher exudation than their sister species native to high nutrient soils in all three species pairs, providing support for repeated evolutionary shifts in response to native soil fertility. Species native to low nutrient soils and those native to high nutrient soils responded similarly to low nutrient treatments with increased exudation of organic acids (fumaric, citric, malic acids) and glucose, potentially as a mechanism to enhance nutrition acquisition. However, species native to low nutrient soils also responded to low nutrient treatments with a larger decrease in exudation of amino acids than species native to high nutrient soils in all three species pairs. This indicates that species native to low nutrient soils have evolved a unique sensitivity to changes in nutrient availability for some, but not all, root exudates. Overall, these repeated evolutionary divergences between species native to low nutrient soils and those native to high nutrient soils provide evidence for the adaptive value of root exudation, and its plasticity, in contrasting soil environments.

Equatorial Pacific peak in biological production regulated by nutrient and upwelling during the late Pliocene/early Pleistocene cooling

NASA Astrophysics Data System (ADS)

Etourneau, J.; Robinson, R. S.; Martinez, P.; Schneider, R.

2013-03-01

The largest increase in export production in the eastern Pacific of the last 5.3 Myr (million years) occurred between 2.2 and 1.6 Myr, a time of major climatic and oceanographic reorganization in the region. Here, we investigate the causes of this event using reconstructions of export production, nutrient supply and oceanic conditions across the Pliocene-Pleistocene in the eastern equatorial Pacific (EEP) for the last 3.2 Myr. Our results indicate that the export production peak corresponds to a cold interval marked by high nutrient supply relative to consumption, as revealed by the low bulk sedimentary 15N/14N (δ15N) and alkenone-derived sea surface temperature (SST) values. This ~ 0.6 million years long episode of enhanced delivery of nutrients to the surface of the EEP was predominantly initiated through the upwelling of nutrient-enriched water sourced in high latitudes. In addition, this phenomenon was likely promoted by the regional intensification of upwelling in response to the development of intense Walker and Hadley atmospheric circulations. Increased nutrient consumption in the polar oceans and enhanced denitrification in the equatorial regions restrained nutrient supply and availability and terminated the high export production event.

Mycorrhizal fungi enhance plant nutrient acquisition and modulate nitrogen loss with variable water regimes.

PubMed

Bowles, Timothy M; Jackson, Louise E; Cavagnaro, Timothy R

2018-01-01

Climate change will alter both the amount and pattern of precipitation and soil water availability, which will directly affect plant growth and nutrient acquisition, and potentially, ecosystem functions like nutrient cycling and losses as well. Given their role in facilitating plant nutrient acquisition and water stress resistance, arbuscular mycorrhizal (AM) fungi may modulate the effects of changing water availability on plants and ecosystem functions. The well-characterized mycorrhizal tomato (Solanum lycopersicum L.) genotype 76R (referred to as MYC+) and the mutant mycorrhiza-defective tomato genotype rmc were grown in microcosms in a glasshouse experiment manipulating both the pattern and amount of water supply in unsterilized field soil. Following 4 weeks of differing water regimes, we tested how AM fungi affected plant productivity and nutrient acquisition, short-term interception of a 15NH4+ pulse, and inorganic nitrogen (N) leaching from microcosms. AM fungi enhanced plant nutrient acquisition with both lower and more variable water availability, for instance increasing plant P uptake more with a pulsed water supply compared to a regular supply and increasing shoot N concentration more when lower water amounts were applied. Although uptake of the short-term 15NH4+ pulse was higher in rmc plants, possibly due to higher N demand, AM fungi subtly modulated NO3- leaching, decreasing losses by 54% at low and high water levels in the regular water regime, with small absolute amounts of NO3- leached (<1 kg N/ha). Since this study shows that AM fungi will likely be an important moderator of plant and ecosystem responses to adverse effects of more variable precipitation, management strategies that bolster AM fungal communities may in turn create systems that are more resilient to these changes. © 2017 John Wiley & Sons Ltd.

Sildenafil citrate treatment enhances amino acid availability in the conceptus and fetal growth in an ovine model of intrauterine growth restriction.

PubMed

Satterfield, M Carey; Bazer, Fuller W; Spencer, Thomas E; Wu, Guoyao

2010-02-01

Adequate placental blood flow is essential for the optimal delivery of nutrients from mother to fetus for conceptus growth. Restricted fetal development results from pathophysiological and environmental factors that alter utero-placental blood flow, placental function, and, therefore, nutrient availability in the fetus. To test this hypothesis, 0, 75, or 150 mg/d sildenafil citrate (Viagra) was administered subcutaneously from d 28 to 115 of gestation to either nutrient-restricted [50% of NRC requirements) or adequately-fed ewes (100% of NRC requirements). On d 115, maternal, fetal, and placental tissues and fluids were collected. Concentrations of total amino acids and polyamines in uterine venous and arterial sera, amniotic and allantoic fluids, and fetal umbilical venous serum were lower (P < 0.05) in nutrient-restricted ewes than in adequately fed ewes, as were the ratios of total amino acids in fetal umbilical venous serum to uterine arterial serum. Sildenafil citrate dose-dependently increased (P < 0.05) total amino acids and polyamines in amniotic fluid, allantoic fluid, and fetal serum without affecting values in maternal serum. Fetal weight was lower (P < 0.05) in nutrient-restricted ewes on d 115. Sildenafil citrate treatment dose-dependently increased (P < 0.05) fetal weight in both nutrient-restricted and adequately fed ewes. This study supports the hypothesis that long-term sildenafil citrate treatment enhances fetal growth, at least in part, by increasing the availability of amino acids in the conceptus. These findings may lead to the clinical use of sildenafil citrate in human pregnancies suspected to be at risk for intrauterine fetal growth retardation.

Canopy and leaf composition drive patterns of nutrient release from pruning residues in a coffee agroforest.

PubMed

Tully, Katherine L; Lawrence, Deborah

2012-06-01

In a coffee agroforest, the crop is cultivated under the shade of fruit-bearing and nitrogen (N)-fixing trees. These trees are periodically pruned to promote flowering and fruiting as well as to make nutrients stored in tree biomass available to plants. We investigated the effect of canopy composition and substrate quality on decomposition rates and patterns of nutrient release from pruning residues in a coffee agroforest located in Costa Rica's Central Valley. Initial phosphorus (P) release was enhanced under a canopy composed solely of N-fixing, Erythrina poeppigiana compared to a mixed canopy of Erythrina and Musa acuminata (banana). Both initial and final N release were similar under the two canopy types. However, after five months of decomposition, a higher proportion of initial N had been released under the single canopy. Although patterns of decomposition and nutrient release were not predicted by initial substrate quality, mass loss in leaf mixtures rates were well predicted by mean mass loss of their component species. This study identifies specific pruning regimes that may regulate N and P release during crucial growth periods, and it suggests that strategic pruning can enhance nutrient availability. For example, during the onset of rapid fruit growth, a two-species mixture may release more P than a three-species mixture. However, by the time of the harvest, the two- and three-species mixtures have released roughly the same amount of N and P. These nutrients do not always follow the same pattern, as N release can be maximized in single-species substrates, while P release is often facilitated in species mixtures. Our study indicates the importance of management practices in mediating patterns of nutrient release. Future research should investigate how canopy composition and farm management can also mediate on-farm nutrient losses.

Litter of the hemiparasite Bartsia alpina enhances plant growth: evidence for a functional role in nutrient cycling.

PubMed

Quested, Helen M; Press, Malcolm C; Callaghan, Terry V

2003-05-01

Hemiparasitic angiosperms concentrate nutrients in their leaves and also produce high quality litter, which can decompose faster and release more nutrients than that of surrounding species. The impact of these litters on plant growth may be particularly important in nutrient-poor communities where hemiparisites can be abundant, such as the sub-Arctic. We tested the hypothesis that plant growth is enhanced by the litter of the hemiparasite Bartsia alpina, in comparison with litter of co-occurring dwarf shrub species, using a pot based bioassay approach. Growth of Betula nana and Poa alpina was up to 51% and 41% greater, respectively, in the presence of Bartsia alpina litter than when grown with dwarf shrub litter (Vaccinium uliginosum, Betula nana and Empetrum nigrum subsp. hermaphroditum). The nutrient concentrations of Betula nana plants grown with Bartsia alpina litter were almost double those of plants grown with dwarf shrub litter, and a significantly greater proportion of biomass was allocated to shoots rather than roots, strongly suggesting that nutrient availability was higher where Bartsia alpina litter was present. The presence of litter from dwarf shrubs, or the moss Hylocomium splendens, did not reduce the positive effect of Bartsia alpina litter on plant growth. E. nigrum litter did not appear to affect plant growth substantially differently from litter of other dwarf shrub species, despite earlier reports of its allelopathic action. The enhanced nutrient uptake and growth of plants in the presence of Bartsia alpina (and potentially other hemiparasitic species) litter could have important implications for communities in which it occurs, including enhanced survival of seedlings of co-occurring species and increased resource patchiness.

Advances in understanding tree fruit-rhizosphere microbiome relationships for enhanced plant health

USDA-ARS?s Scientific Manuscript database

Host-microbe interactions in the rhizosphere influence numerous processes that determine plant productivity and health. The importance of the rhizo-microbiome for plant function is well known, influencing functions ranging from protection of the plant from pathogen attack to enhanced nutrient avail...

Parasite and nutrient enrichment effects on Daphnia interspecific competition.

PubMed

Decaestecker, Ellen; Verreydt, Dino; De Meester, Luc; Declerck, Steven A J

2015-05-01

Increased productivity due to nutrient enrichment is hypothesized to affect density-dependent processes, such as transmission success of horizontally transmitting parasites. Changes in nutrient availability can also modify the stoichiometry and condition of individual hosts, which may affect their susceptibility for parasites as well as the growth conditions for parasites within the host. Consequently, if not balanced by increased host immuno-competence or life history responses, changes in the magnitude of parasite effects with increasing nutrient availability are expected. If these parasite effects are host-species specific, this may lead to shifts in the host community structure. We here used the Daphnia- parasite model system to study the effect of nutrient enrichment on parasite-mediated competition in experimental mesocosms. In the absence of parasites, D. magna was competitively dominant to D. pulex at both low and high nutrient levels. Introduction of parasites resulted in infections of D. magna, but not of D. pulex and, as such, reversed the competitive hierarchy between these two species. Nutrient addition resulted in an increased prevalence and infection intensity of some of the parasites on D. magna. However, there was no evidence that high nutrient levels enhanced negative effects of parasites on the hosts. Costs associated with parasite infections may have been compensated by better growth conditions for D. magna in the presence of high nutrient levels.

Recapturing nutrients from dairy waste using biochar

NASA Astrophysics Data System (ADS)

Sarkhot, D.; Ghezzehei, T. A.; Berhe, A. A.

2009-12-01

Biochar or biomass derived black carbon is known to be highly resistant to decomposition with half-life periods ranging from hundreds of years to millennia. It is also reported to enhance soil productivity due to high nutrient retention and favorable effects on soil pH, water retention capacity as well as microbial population. Brazilian Terra Preta soils have shown the potential of biochar for long-term carbon sequestration capacity and productivity of soil and many researchers have now focused on utilizing this phenomenon to create fertile, carbon-rich soils, called Terra Preta Nova. Although the highly adsorptive nature of biochar is well characterized, the potential for using biochar in environmental cleanup efforts is relatively unexplored. Dairy waste is a source of significant water pollution because it introduces excess nutrients such as phosphates and nitrates into the soil and water system. Since many soils have limited capacity to retain nitrate and phosphate, especially for long periods of time, the utility of dairy waste manure to enhance soil fertility and nutrient availability to plants is limited. Here, we present results from a project that we started to determine the potential of biochar to recover the excess nutrients from dairy flushed manure. In this initial study, a commercially available biochar amendment was ground and used in a batch sorption experiment with the dairy flushed manure from a local dairy in Merced, California. Four manure dilutions viz. 10, 25, 50 and 100%, and three shaking times, viz. 1, 12 and 24 hours were used for this study. We then calculated the amount of ammonia, nitrate and phosphate adsorbed by the biochar using differences in nutrient concentrations before and after the sorption experiment. Biochar showed significant capacity of adsorbing these nutrients, suggesting a potential for controlling the dairy pollution. The resulting enriched biochar can potentially act as a slow release fertilizer and enhance soil productivity as well as increasing the long-term carbon sequestration potential of soils. We are currently initiating further research to determine the desorption potenial of the biochar sorbed nutrients in soil.

Effects of replacing soybean meal with canola meal or treated canola meal on ruminal digestion, and omasal nutrient flow in lactating dairy cows

USDA-ARS?s Scientific Manuscript database

Treated canola meal (TCM) was produced as an attempt to increase the rumen undegradable protein (RUP) fraction of canola meal (CM) with the goal of enhancing amino acid (AA) availability for absorption in the small intestine of dairy cows. The objective of this study was to measure nutrient and micr...

Nitrogen regulation of transpiration controls mass-flow acquisition of nutrients.

PubMed

Matimati, Ignatious; Verboom, G Anthony; Cramer, Michael D

2014-01-01

Transpiration may enhance mass-flow of nutrients to roots, especially in low-nutrient soils or where the root system is not extensively developed. Previous work suggested that nitrogen (N) may regulate mass-flow of nutrients. Experiments were conducted to determine whether N regulates water fluxes, and whether this regulation has a functional role in controlling the mass-flow of nutrients to roots. Phaseolus vulgaris were grown in troughs designed to create an N availability gradient by restricting roots from intercepting a slow-release N source, which was placed at one of six distances behind a 25 μm mesh from which nutrients could move by diffusion or mass-flow (termed 'mass-flow' treatment). Control plants had the N source supplied directly to their root zone so that N was available through interception, mass-flow, and diffusion (termed 'interception' treatment). 'Mass-flow' plants closest to the N source exhibited 2.9-fold higher transpiration (E), 2.6-fold higher stomatal conductance (gs), 1.2-fold higher intercellular [CO2] (Ci), and 3.4-fold lower water use efficiency than 'interception' plants, despite comparable values of photosynthetic rate (A). E, gs, and Ci first increased and then decreased with increasing distance from the N source to values even lower than those of 'interception' plants. 'Mass-flow' plants accumulated phosphorus and potassium, and had maximum concentrations at 10mm from the N source. Overall, N availability regulated transpiration-driven mass-flow of nutrients from substrate zones that were inaccessible to roots. Thus when water is available, mass-flow may partially substitute for root density in providing access to nutrients without incurring the costs of root extension, although the efficacy of mass-flow also depends on soil nutrient retention and hydraulic properties.

Nitrogen regulation of transpiration controls mass-flow acquisition of nutrients

PubMed Central

Matimati, Ignatious

2014-01-01

Transpiration may enhance mass-flow of nutrients to roots, especially in low-nutrient soils or where the root system is not extensively developed. Previous work suggested that nitrogen (N) may regulate mass-flow of nutrients. Experiments were conducted to determine whether N regulates water fluxes, and whether this regulation has a functional role in controlling the mass-flow of nutrients to roots. Phaseolus vulgaris were grown in troughs designed to create an N availability gradient by restricting roots from intercepting a slow-release N source, which was placed at one of six distances behind a 25 μm mesh from which nutrients could move by diffusion or mass-flow (termed ‘mass-flow’ treatment). Control plants had the N source supplied directly to their root zone so that N was available through interception, mass-flow, and diffusion (termed ‘interception’ treatment). ‘Mass-flow’ plants closest to the N source exhibited 2.9-fold higher transpiration (E), 2.6-fold higher stomatal conductance (g s), 1.2-fold higher intercellular [CO2] (C i), and 3.4-fold lower water use efficiency than ‘interception’ plants, despite comparable values of photosynthetic rate (A). E, g s, and C i first increased and then decreased with increasing distance from the N source to values even lower than those of ‘interception’ plants. ‘Mass-flow’ plants accumulated phosphorus and potassium, and had maximum concentrations at 10mm from the N source. Overall, N availability regulated transpiration-driven mass-flow of nutrients from substrate zones that were inaccessible to roots. Thus when water is available, mass-flow may partially substitute for root density in providing access to nutrients without incurring the costs of root extension, although the efficacy of mass-flow also depends on soil nutrient retention and hydraulic properties. PMID:24231035

Minimising losses to predation during microalgae cultivation.

PubMed

Flynn, Kevin J; Kenny, Philip; Mitra, Aditee

2017-01-01

We explore approaches to minimise impacts of zooplanktonic pests upon commercial microalgal crops using system dynamics models to describe algal growth controlled by light and nutrient availability and zooplankton growth controlled by crop abundance and nutritional quality. Losses of microalgal crops are minimised when their growth is fastest and, in contrast, also when growing slowly under conditions of nutrient exhaustion. In many culture systems, however, dwindling light availability due to self-shading in dense suspensions favours slow growth under nutrient sufficiency. Such a situation improves microalgal quality as prey, enhancing zooplankton growth, and leads to rapid crop collapse. Timing of pest entry is important; crop losses are least likely in established, nutrient-exhausted microalgal communities grown for high C-content (e.g. for biofuels). A potentially useful approach is to promote a low level of P-stress that does not adversely affect microalgal growth but which produces a crop that is suboptimal for zooplankton growth.

Equatorial Pacific peak in biological production regulated by nutrient and upwelling during the late Pliocene/early Pleistocene cooling

NASA Astrophysics Data System (ADS)

Etourneau, J.; Robinson, R. S.; Martinez, P.; Schneider, R.

2013-08-01

The largest increase in export production in the eastern Pacific of the last 5.3 Myr (million years) occurred between 2.2 and 1.6 Myr, a time of major climatic and oceanographic reorganization in the region. Here, we investigate the causes of this event using reconstructions of export production, nutrient supply and oceanic conditions across the Pliocene-Pleistocene in the eastern equatorial Pacific (EEP) for the last 3.2 Myr. Our results indicate that the export production peak corresponds to a cold interval marked by high nutrient supply relative to consumption, as revealed by the low bulk sedimentary 15N/14N (δ15N) and alkenone-derived sea surface temperature (SST) values. This ∼0.6 million year long episode of enhanced delivery of nutrients to the surface of the EEP was predominantly initiated through the upwelling of nutrient-enriched water sourced in high latitudes. In addition, this phenomenon was likely promoted by the regional intensification of upwelling in response to the development of intense Walker and Hadley atmospheric circulations. Increased nutrient consumption in the polar oceans and enhanced denitrification in the equatorial regions restrained nutrient supply and availability and terminated the high export production event.

Metal availability, soil nutrient, and enzyme activity in response to application of organic amendments in Cd-contaminated soil.

PubMed

Yang, Zhanbiao; Liu, Lixia; Lv, Yanfeng; Cheng, Zhang; Xu, Xiaoxun; Xian, Junren; Zhu, Xuemei; Yang, Yuanxiang

2018-01-01

The study investigated the effects of organic amendments: green tea amendment (GTA) and oil cake amendment (OCA) on Cd bioavailability, soil nutrients, and soil enzyme activity in Cd-contaminated soil. The amendments were added to the soil at the doses of 1, 3, and 5% and were incubated for 45 days. Then, pakchoi cabbage was planted to test the remediation effect of the above two organic amendments. The diethylenetriaminepentaacetic acid (DTPA)-extractable Cd in GTA and OCA treatments was reduced by 14.69-27.51 and 13.75-68.77%, respectively, compared to no amendment-applied treatment. The application of GTA and OCA notably decreased the proportion of exchangeable fraction of Cd, but increased the percentage of oxide and organic-bound fraction of Cd, thereby suppressing the uptake by pakchoi cabbage. Cd concentration of aboveground parts decreased by 8.21-18.05 and 7.77-35.89% in GTA and OCA treatments, respectively. Relative to the no amendment-applied treatment, both GTA and OCA had enhanced soil nutrients and enzyme activities largely. Redundancy analysis showed that organic matter, total P, available N, and DTPA-extractable Cd significantly affected the enzyme activities. Furthermore, the application of OCA at the dose of 5% was more effective in reducing bioavailable Cd, enhancing soil available nutrients and urease and catalase activities in contaminated soil. These results indicated that oil cake should be used to immobilize metal and improve fertility and quality of Cd-contaminated soil.

Impacts of Maternal Nutrition on Vascularity of Nutrient Transferring Tissues during Gestation and Lactation

PubMed Central

Vonnahme, Kimberly A.; Lemley, Caleb O.; Caton, Joel S.; Meyer, Allison M.

2015-01-01

As the demand for food increases with exponential growth in the world population, it is imperative that we understand how to make livestock production as efficient as possible in the face of decreasing available natural resources. Moreover, it is important that livestock are able to meet their metabolic demands and supply adequate nutrition to developing offspring both during pregnancy and lactation. Specific nutrient supplementation programs that are designed to offset deficiencies, enhance efficiency, and improve nutrient supply during pregnancy can alter tissue vascular responses, fetal growth, and postnatal offspring outcomes. This review outlines how vascularity in nutrient transferring tissues, namely the maternal gastrointestinal tract, the utero-placental tissue, and the mammary gland, respond to differing nutritional planes and other specific nutrient supplementation regimes. PMID:25984740

Increased sporulation of vesicular-arbuscular mycorrhizal fungi by manipulation of nutrient regimens.

PubMed

Douds, D D; Schenck, N C

1990-02-01

Adjustment of pot culture nutrient solutions increased root colonization and sporulation of vesicular-arbuscular mycorrhizal (VAM) fungi. Paspalum notatum Flugge and VAM fungi were grown in a sandy soil low in N and available P. Hoagland nutrient solution without P enhanced sporulation in soil and root colonization of Acaulospora longula, Scutellospora heterogama, Gigaspora margarita, and a wide range of other VAM fungi over levels produced by a tap water control or nutrient solutions containing P. However, Glomus intraradices produced significantly more spores in plant roots in the tap water control treatment. The effect of the nutrient solutions was not due solely to N nutrition, because the addition of NH(4)NO(3) decreased both colonization and sporulation by G. margarita relative to levels produced by Hoagland solution without P.

Biochar derived from corn straw affected availability and distribution of soil nutrients and cotton yield.

PubMed

Tian, Xiaofei; Li, Chengliang; Zhang, Min; Wan, Yongshan; Xie, Zhihua; Chen, Baocheng; Li, Wenqing

2018-01-01

Biochar application as a soil amendment has been proposed as a strategy to improve soil fertility and increase crop yields. However, the effects of successive biochar applications on cotton yields and nutrient distribution in soil are not well documented. A three-year field study was conducted to investigate the effects of successive biochar applications at different rates on cotton yield and on the soil nutrient distribution in the 0-100 cm soil profile. Biochar was applied at 0, 5, 10, and 20 t ha-1 (expressed as Control, BC5, BC10, and BC20, respectively) for each cotton season, with identical doses of chemical fertilizers. Biochar enhanced the cotton lint yield by 8.0-15.8%, 9.3-13.9%, and 9.2-21.9% in 2013, 2014, and 2015, respectively, and high levels of biochar application achieved high cotton yields each year. Leaching of soil nitrate was reduced, while the pH values, soil organic carbon, total nitrogen (N), and available K content of the 0-20 cm soil layer were increased in 2014 and 2015. However, the changes in the soil available P content were less substantial. This study suggests that successive biochar amendments have the potential to enhance cotton productivity and soil fertility while reducing nitrate leaching.

The influence of microtopography on soil nutrients in created mitigation wetlands

USGS Publications Warehouse

Moser, K.F.; Ahn, C.; Noe, G.B.

2009-01-01

This study explores the relationship between microtopography and soil nutrients (and trace elements), comparing results for created and reference wetlands in Virginia, and examining the effects of disking during wetland creation. Replicate multiscale tangentially conjoined circular transects were used to quantify microtopography both in terms of elevation and by two microtopographic indices. Corresponding soil samples were analyzed for moisture content, total C and N, KCl-extractable NH4-N and NO3-N, and Mehlich-3 extractable P, Ca, Mg, K, Al, Fe, and Mn. Means and variances of soil nutrient/element concentrations were compared between created and natural wetlands and between disked and nondisked created wetlands. Natural sites had higher and more variable soil moisture, higher extractable P and Fe, lower Mn than created wetlands, and comparatively high variability in nutrient concentrations. Disked sites had higher soil moisture, NH4-N, Fe, and Mn than did nondisked sites. Consistently low variances (Levene test for inequality) suggested that nondisked sites had minimal nutrient heterogeneity. Across sites, low P availability was inferred by the molar ratio (Mehlich-3 [P/(Al + Fe)] < 0.06); strong intercorrelations among total C, total N, and extractable Fe, Al, and P suggested that humic-metal-P complexes may be important for P retention and availability. Correlations between nutrient/element concentrations and microtopographic indices suggested increased Mn and decreased K and Al availability with increased surface roughness. Disking appears to enhance water and nutrient retention, as well as nutrient heterogeneity otherwise absent from created wetlands, thus potentially promoting ecosystem development. ?? 2008 Society for Ecological Restoration International.

Refuse dumps from leaf-cutting ant nests reduce the intensity of above-ground competition among neighboring plants in a Patagonian steppe

NASA Astrophysics Data System (ADS)

Farji-Brener, Alejandro G.; Lescano, María Natalia

2017-11-01

In arid environments, the high availability of sunlight due to the scarcity of trees suggests that plant competition take place mainly belowground for water and nutrients. However, the occurrence of soil disturbances that increase nutrient availability and thereby promote plant growth may enhance shoot competition between neighboring plants. We conducted a greenhouse experiment to evaluate the influence of the enriched soil patches generated by the leaf-cutting ant, Acromyrmex lobicornis, on the performance of the alien forb Carduus thoermeri (Asteraceae) under different intraspecific competition scenarios. Our results showed that substrate type and competition scenario affected mainly aboveground plant growth. As expected, plants growing without neighbors and in nutrient-rich ant refuse dumps showed more aboveground biomass than plants growing with neighbors and in nutrient-poor steppe soils. However, aboveground competition was more intense in nutrient-poor substrates: plants under shoot and full competition growing in the nutrient-rich ant refuse dumps showed higher biomass than those growing on steppe soils. Belowground biomass was similar among focal plants growing under different substrate type. Our results support the traditional view that increments in resource availability reduce competition intensity. Moreover, the fact that seedlings in this sunny habitat mainly compete aboveground illustrates how limiting factors may be scale-dependent and change in importance as plants grow.

Investigation of the effects of slow-release fertilizer and struvite in biodegradation in filter drains and potential application of treated water in irrigation of road verges.

PubMed

Theophilus, Stephen C; Mbanaso, Fredrick U; Nnadi, Ernest O; Onyedeke, Kingsley T

2017-11-14

Filter drains are usually laid along the margins of highways. Highway runoffs are polluted with hydrocarbons and high levels of total dissolved solids. Therefore, effective pollution removal mechanism is necessary in order to avoid contamination of surrounding soils and groundwater. Biodegradation is amongst pollution removal mechanisms in filter drains, but it is a relatively slow process which is dependent on wide range of factors including the type of pollutant and availability of nutrients. This paper reports on a study conducted to investigate the impact of slow-release fertilizer and struvite in enhancement of biodegradation of hydrocarbon in filter drains. Filter drain models incorporated with geotextile were challenged with cumulative oil loading of 178 mg/m 2 /week with a view to comparing the efficiency of these two nutrient sources under high oil pollution loading and realistic rainfall conditions of 13 mm/week. Nutrients and street dust were applied at one-off rate of 17 g/m 2 and 1.55 g/rig to provide nutrient enhancement and simulate field conditions respectively. The impact of the nutrients was studied by monitoring bacterial and fungal growth using nutrient agar, Rose Bengal Agar media and CO2 evolution. EC, pH, heavy metals, TPH, elemental analysis and SAR were used to investigate water quality of effluent of filter drains for potential application as irrigation fluid for trees and flowers planted on road verges. The results show that nutrient application encouraged microbial activities and enhanced biodegradation rates with differences in type of nutrient applied. Also, it was observed that incorporation of geotextiles in filter drains improved pollution retention efficiency and there is a potential opportunity for utilization of struvite in SuDS systems as sustainable nutrient source.

Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions.

PubMed

Gebremikael, Mesfin T; Steel, Hanne; Buchan, David; Bert, Wim; De Neve, Stefaan

2016-09-08

The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota.

Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions

NASA Astrophysics Data System (ADS)

Gebremikael, Mesfin T.; Steel, Hanne; Buchan, David; Bert, Wim; de Neve, Stefaan

2016-09-01

The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota.

Enhanced Nitrogen Availability in Karst Ecosystems by Oxalic Acid Release in the Rhizosphere

PubMed Central

Pan, Fujing; Liang, Yueming; Zhang, Wei; Zhao, Jie; Wang, Kelin

2016-01-01

In karst ecosystems, a high level of CaCO3 enhances the stabilization of soil organic matter (SOM) and causes nitrogen (N) and/or phosphorus (P) limitation in plants. Oxalic acid has been suggested to be involved in the nutrient-acquisition strategy of plants because its addition can temporarily relieve nutrient limitation. Therefore, understanding how oxalic acid drives N availability may help support successful vegetation restoration in the karst ecosystems of southwest China. We tested a model suggested by Clarholm et al. (2015) where oxalate reacts with Ca bridges in SOM, thus exposing previously protected areas to enzymatic attacks in a way that releases N for local uptake. We studied the effects of oxalic acid, microbial biomass carbon (MBC), and β-1,4-N-acetylglucosaminidase (NAG) on potential N mineralization rates in rhizosphere soils of four plant species (two shrubs and two trees) in karst areas. The results showed that rhizosphere soils of shrubs grown on formerly deforested land had significantly lower oxalic acid concentrations and NAG activity than that of trees in a 200-year-old forest. The levels of MBC in rhizosphere soils of shrubs were significantly lower than those of trees in the growing season, but the measure of shrubs and trees were similar in the non-growing season; the potential N mineralization rates showed a reverse pattern. Positive relationships were found among oxalic acid, MBC, NAG activity, and potential N mineralization rates for both shrubs and trees. This indicated that oxalic acid, microbes, and NAG may enhance N availability for acquisition by plants. Path analysis showed that oxalic acid enhanced potential N mineralization rates indirectly through inducing microbes and NAG activities. We found that the exudation of oxalic acid clearly provides an important mechanism that allows plants to enhance nutrient acquisition in karst ecosystems. PMID:27252713

Element interactions limit soil carbon storage

PubMed Central

van Groenigen, Kees-Jan; Six, Johan; Hungate, Bruce A.; de Graaff, Marie-Anne; van Breemen, Nico; van Kessel, Chris

2006-01-01

Rising levels of atmospheric CO2 are thought to increase C sinks in terrestrial ecosystems. The potential of these sinks to mitigate CO2 emissions, however, may be constrained by nutrients. By using metaanalysis, we found that elevated CO2 only causes accumulation of soil C when N is added at rates well above typical atmospheric N inputs. Similarly, elevated CO2 only enhances N2 fixation, the major natural process providing soil N input, when other nutrients (e.g., phosphorus, molybdenum, and potassium) are added. Hence, soil C sequestration under elevated CO2 is constrained both directly by N availability and indirectly by nutrients needed to support N2 fixation. PMID:16614072

Viral pathogen production in a wild grass host driven by host growth and soil nitrogen.

PubMed

Whitaker, Briana K; Rúa, Megan A; Mitchell, Charles E

2015-08-01

Nutrient limitation is a basic ecological constraint that has received little attention in studies on virus production and disease dynamics. Nutrient availability could directly limit the production of viral nucleic acids and proteins, or alternatively limit host growth and thus indirectly limit metabolic pathways necessary for viral replication. In order to compare direct and indirect effects of nutrient limitation on virus production within hosts, we manipulated soil nitrogen (N) and phosphorus (P) availability in a glasshouse for the wild grass host Bromus hordeaceus and the viral pathogen Barley yellow dwarf virus-PAV. We found that soil N additions increased viral concentrations within host tissues, and the effect was mediated by host growth. Specifically, in statistical models evaluating the roles of host biomass production, leaf N and leaf P, viral production depended most strongly on host biomass, rather than the concentration of either nutrient. Furthermore, at low soil N, larger plants supported greater viral concentrations than smaller ones, whereas at high N, smaller plants supported greater viral concentrations. Our results suggest that enhanced viral productivity under N enrichment is an indirect consequence of nutrient stimulation to host growth rate. Heightened pathogen production in plants has important implications for a world facing increasing rates of nutrient deposition. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Context-dependency in the effects of nutrient loading and consumers on the availability of space in marine rocky environments.

PubMed

Bulleri, Fabio; Russell, Bayden D; Connell, Sean D

2012-01-01

Enhanced nutrient loading and depletion of consumer populations interact to alter the structure of aquatic plant communities. Nonetheless, variation between adjacent habitats in the relative strength of bottom-up (i.e. nutrients) versus top-down (i.e. grazing) forces as determinants of community structure across broad spatial scales remains unexplored. We experimentally assessed the importance of grazing pressure and nutrient availability on the development of macroalgal assemblages and the maintenance of unoccupied space in habitats differing in physical conditions (i.e. intertidal versus subtidal), across regions of contrasting productivity (oligotrophic coasts of South Australia versus the more productive coasts of Eastern Australia). In Eastern Australia, grazers were effective in maintaining space free of macroalgae in both intertidal and subtidal habitats, irrespective of nutrient levels. Conversely, in South Australia, grazers could not prevent colonization of space by turf-forming macroalgae in subtidal habitats regardless of nutrients levels, yet in intertidal habitats removal of grazers reduced unoccupied space when nutrients were elevated. Assessing the effects of eutrophication in coastal waters requires balancing our understanding between local consumer pressure and background oceanographic conditions that affect productivity. This broader-based understanding may assist in reconciling disproportionately large local-scale variation, a characteristic of ecology, with regional scale processes that are often of greater relevance to policy making and tractability to management.

Increased plant growth from nitrogen addition should conserve phosphorus in terrestrial ecosystems.

PubMed

Perring, Michael P; Hedin, Lars O; Levin, Simon A; McGroddy, Megan; de Mazancourt, Claire

2008-02-12

Inputs of available nitrogen (N) to ecosystems have grown over the recent past. There is limited general understanding of how increased N inputs affect the cycling and retention of other potentially limiting nutrients. Using a plant-soil nutrient model, and by explicitly coupling N and phosphorus (P) in plant biomass, we examine the impact of increasing N supply on the ecosystem cycling and retention of P, assuming that the main impact of N is to increase plant growth. We find divergent responses in the P cycle depending on the specific pathway by which nutrients are lost from the ecosystem. Retention of P is promoted if the relative propensity for loss of plant available P is greater than that for the loss of less readily available organic P. This is the first theoretical demonstration that the coupled response of ecosystem-scale nutrient cycles critically depends on the form of nutrient loss. P retention might be lessened, or reversed, depending on the kinetics and size of a buffering reactive P pool. These properties determine the reactive pool's ability to supply available P. Parameterization of the model across a range of forest ecosystems spanning various environmental and climatic conditions indicates that enhanced plant growth due to increased N should trigger increased P conservation within ecosystems while leading to more dissolved organic P loss. We discuss how the magnitude and direction of the effect of N may also depend on other processes.

Biochar derived from corn straw affected availability and distribution of soil nutrients and cotton yield

PubMed Central

Tian, Xiaofei; Zhang, Min; Wan, Yongshan; Xie, Zhihua; Chen, Baocheng; Li, Wenqing

2018-01-01

Biochar application as a soil amendment has been proposed as a strategy to improve soil fertility and increase crop yields. However, the effects of successive biochar applications on cotton yields and nutrient distribution in soil are not well documented. A three-year field study was conducted to investigate the effects of successive biochar applications at different rates on cotton yield and on the soil nutrient distribution in the 0–100 cm soil profile. Biochar was applied at 0, 5, 10, and 20 t ha-1 (expressed as Control, BC5, BC10, and BC20, respectively) for each cotton season, with identical doses of chemical fertilizers. Biochar enhanced the cotton lint yield by 8.0–15.8%, 9.3–13.9%, and 9.2–21.9% in 2013, 2014, and 2015, respectively, and high levels of biochar application achieved high cotton yields each year. Leaching of soil nitrate was reduced, while the pH values, soil organic carbon, total nitrogen (N), and available K content of the 0–20 cm soil layer were increased in 2014 and 2015. However, the changes in the soil available P content were less substantial. This study suggests that successive biochar amendments have the potential to enhance cotton productivity and soil fertility while reducing nitrate leaching. PMID:29324750

The effects of CO2 and nutrient fertilisation on the growth and temperature response of the mangrove Avicennia germinans.

PubMed

Reef, Ruth; Slot, Martijn; Motro, Uzi; Motro, Michal; Motro, Yoav; Adame, Maria F; Garcia, Milton; Aranda, Jorge; Lovelock, Catherine E; Winter, Klaus

2016-08-01

In order to understand plant responses to both the widespread phenomenon of increased nutrient inputs to coastal zones and the concurrent rise in atmospheric CO2 concentrations, CO2-nutrient interactions need to be considered. In addition to its potential stimulating effect on photosynthesis and growth, elevated CO2 affects the temperature response of photosynthesis. The scarcity of experiments testing how elevated CO2 affects the temperature response of tropical trees hinders our ability to model future primary productivity. In a glasshouse study, we examined the effects of elevated CO2 (800 ppm) and nutrient availability on seedlings of the widespread mangrove Avicennia germinans. We assessed photosynthetic performance, the temperature response of photosynthesis, seedling growth and biomass allocation. We found large synergistic gains in both growth (42 %) and photosynthesis (115 %) when seedlings grown under elevated CO2 were supplied with elevated nutrient concentrations relative to their ambient growing conditions. Growth was significantly enhanced under elevated CO2 only under high-nutrient conditions, mainly in above-ground tissues. Under low-nutrient conditions and elevated CO2, root volume was more than double that of seedlings grown under ambient CO2 levels. Elevated CO2 significantly increased the temperature optimum for photosynthesis by ca. 4 °C. Rising CO2 concentrations are likely to have a significant positive effect on the growth rate of A. germinans over the next century, especially in areas where nutrient availability is high.

Biochar-enhanced composts reduce the potential leaching of nutrients and heavy metals and suppress plant-parasitic nematodes in excessively fertilized cucumber soils.

PubMed

Cao, Yune; Gao, Yanming; Qi, Yanbin; Li, Jianshe

2018-03-01

Excessive fertilization is a common agricultural practice that has largely reduced soil nutrient retention capacity and led to nutrient leaching in China. To reduce nutrient leaching, in this study, we evaluated the application of biochar, compost, and biochar-compost on soil properties, leaching water quality, and cucumber plant growth in soils with different nutrient levels. In general, the concentrations of nutrients and heavy metals in leaching water were higher under high-nutrient conditions than under low-nutrient conditions. Both biochar and compost efficiently enhanced soil cation exchange capacity (CEC), water holding capacity (WHC), and microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP), reduced the potential leaching of nutrients and heavy metals, and improved plant growth. The efficiency of biochar and compost in soil CEC, WHC, MBC, MBN, and MBP and plant growth was enhanced when applied jointly. In addition, biochar and biochar-enhanced compost efficiently suppressed plant-parasitic nematode infestation in a soil with high levels of both N and P. Our results suggest that biochar-enhanced compost can reduce the potential environmental risks in excessively fertilized vegetable soils.

Feasibility of Estimating Relative Nutrient Contributions of Agriculture and Forests Using MODIS Time Series

NASA Technical Reports Server (NTRS)

Ross, Kenton W.; Gasser, Gerald; Spiering, Bruce

2010-01-01

Around the Gulf of Mexico, high-input crops in several regions make a significant contribution to nutrient loading of small to medium estuaries and to the near-shore Gulf. Some crops cultivated near the coast include sorghum in Texas, rice in Texas and Louisiana, sugarcane in Florida and Louisiana, citrus orchards in Florida, pecan orchards in Mississippi and Alabama, and heavy sod and ornamental production around Mobile and Tampa Bay. In addition to crops, management of timberlands in proximity to the coasts also plays a role in nutrient loading. In the summer of 2008, a feasibility project is planned to explore the use of NASA data to enhance the spatial and temporal resolution of near-coast nutrient source information available to the coastal community. The purpose of this project is to demonstrate the viability of nutrient source information products applicable to small to medium watersheds surrounding the Gulf of Mexico. Conceptually, these products are intended to complement estuarine nutrient monitoring.

Nutrient enrichment enhances black band disease progression in corals

NASA Astrophysics Data System (ADS)

Voss, Joshua D.; Richardson, Laurie L.

2006-11-01

Infectious diseases are recognized as significant contributors to the dramatic loss of corals observed worldwide. However, the causes of increased coral disease prevalence and severity are not well understood. One potential factor is elevated nutrient concentration related to localized anthropogenic activities such as inadequate waste water treatment or terrestrial runoff. In this study the effect of nutrient enrichment on the progression of black band disease (BBD) was investigated using both in situ and laboratory experiments. Experimental increases in localized nutrient availability using commercial time release fertilizer in situ resulted in doubling of BBD progression and coral tissue loss in the common reef framework coral Siderastrea siderea. Laboratory experiments in which artificially infected S. siderea colonies were exposed to increased nitrate concentrations (up to 3 μM) demonstrated similar increases in BBD progression. These findings provide evidence that the impacts of this disease on coral populations are exacerbated by nutrient enrichment and that management to curtail excess nutrient loading may be important for reducing coral cover loss due to BBD.

Feasibility of Estimating Relative Nutrient Contributions of Agriculture using MODIS Time Series

NASA Technical Reports Server (NTRS)

Ross, Kenton W.; Gasser, Gerald; Spiering, Bruce

2008-01-01

Around the Gulf of Mexico, high-input crops in several regions make a significant contribution to nutrient loading of small to medium estuaries and to the near-shore Gulf. Some crops cultivated near the coast include sorghum in Texas, rice in Texas and Louisiana, sugarcane in Florida and Louisiana, citrus orchards in Florida, pecan orchards in Mississippi and Alabama, and heavy sod and ornamental production around Mobile and Tampa Bay. In addition to crops, management of timberlands in proximity to the coasts also plays a role in nutrient loading. In the summer of 2008, a feasibility project is planned to explore the use of NASA data to enhance the spatial and temporal resolution of near-coast nutrient source information available to the coastal community. The purpose of this project is to demonstrate the viability of nutrient source information products applicable to small to medium watersheds surrounding the Gulf of Mexico. Conceptually, these products are intended to complement estuarine nutrient monitoring.

Nutrients, high light, and shallow depths favor the expansion of the brown macroalgae Turbinaria ornata in the coral reefs of Mo'orea, French Polynesia

NASA Astrophysics Data System (ADS)

Rogers, J.; Cordoba, G.; Nieves, M.; Barber, P. H.; Fong, P.; Sura, S.

2016-02-01

Coral reefs provide food, recreation and economic resources for billions of people. Despite this importance, anthropogenic stressors including climate change and nutrification threaten coral reefs globally, causing phase-shifts to algal dominated ecosystems and loss of coral habitats. Throughout the tropical South Pacific, the brown macroalgae Turbinaria ornata is expanding its range and now dominates areas where corals used to thrive, especially shallow areas on fringing reefs of French Polynesia. Abiotic factors like light and nutrient availability could enhance the expansion of T. ornata by promoting its growth or by making it physically tougher, which could reduce herbivory pressure and enhance its survival in high energy zones. To understand the abiotic factors favoring growth and survival of T. ornata in Mo'orea, French Polynesia, we conducted a field experiment testing the effect of nutrients (+/- fertilizer), depth (1m within Turbinaria zone, 1.5m at border, 2m below depth distribution), and light (+/- shade) on the growth and toughness of T. ornata. Three-factor ANOVA showed that an interaction between nutrients and light favored T. ornata biomass accumulation (p=0.04). In addition, T. ornata from shallow depths were significantly tougher than intermediate depths (p=0.01). These results imply that nutrient enrichment combined with high light levels common in shallow coral reefs may promote growth and expansion of T. ornata to near-shore reef environments. Increased survival and population growth is likely further enhanced by increased toughness of T. ornata in shallow areas, which may limit herbivore grazing and improve survival in strong wave action or currents. Future research should examine whether reducing nutrient loading to coastal waters may limit the expansion of T. ornata in the South Pacific.

Nutrients, High Light and Shallow Depths Favor the Expansion of the Brown Macroalgae Turbinaria ornata in the Coral Reefs of Mo'orea, French Polynesia

NASA Astrophysics Data System (ADS)

Nieves, M.; Cordoba, G.; Rogers, J.

2016-02-01

Coral reefs provide food, recreation and economic resources for billions of people. Despite this importance, anthropogenic stressors including climate change and nutrification threaten coral reefs globally, causing phase-shifts to algal dominated ecosystems and loss of coral habitats. Throughout the tropical South Pacific, the brown macroalgae Turbinaria ornata is expanding its range and now dominates areas where corals used to thrive, especially shallow areas on fringing reefs of French Polynesia. Abiotic factors like light and nutrient availability could enhance the expansion of T. ornata by promoting its growth or by making it physically tougher, which could reduce herbivory pressure and enhance its survival in high energy zones. To understand the abiotic factors favoring growth and survival of T. ornata in Mo'orea, French Polynesia, we conducted a field experiment testing the effect of nutrients (+/- fertilizer), depth (1m within Turbinaria zone, 1.5m at border, 2m below depth distribution), and light (+/- shade) on the growth and toughness of T. ornata. Three-factor ANOVA showed that an interaction between nutrients and light favored T. ornata biomass accumulation (p=0.04). In addition, T. ornata from shallow depths were significantly tougher than those at intermediate depths (p=0.01). These results imply that nutrient enrichment combined with high light levels common in shallow coral reefs may promote growth and expansion of T. ornata to near-shore reef environments. Increased survival and population growth is likely further enhanced by increased toughness of T. ornata in shallow areas, which may limit herbivore grazing and improve survival in strong wave action or currents. Future research should examine whether reducing nutrient loading to coastal waters may limit the expansion of T. ornata in the South Pacific.

Warming effects on permafrost ecosystem carbon fluxes associated with plant nutrients.

PubMed

Li, Fei; Peng, Yunfeng; Natali, Susan M; Chen, Kelong; Han, Tianfeng; Yang, Guibiao; Ding, Jinzhi; Zhang, Dianye; Wang, Guanqin; Wang, Jun; Yu, Jianchun; Liu, Futing; Yang, Yuanhe

2017-11-01

Large uncertainties exist in carbon (C)-climate feedback in permafrost regions, partly due to an insufficient understanding of warming effects on nutrient availabilities and their subsequent impacts on vegetation C sequestration. Although a warming climate may promote a substantial release of soil C to the atmosphere, a warming-induced increase in soil nutrient availability may enhance plant productivity, thus offsetting C loss from microbial respiration. Here, we present evidence that the positive temperature effect on carbon dioxide (CO 2 ) fluxes may be weakened by reduced plant nitrogen (N) and phosphorous (P) concentrations in a Tibetan permafrost ecosystem. Although experimental warming initially enhanced ecosystem CO 2 uptake, the increased rate disappeared after the period of peak plant growth during the early growing season, even though soil moisture was not a limiting factor in this swamp meadow ecosystem. We observed that warming did not significantly affect soil extractable N or P during the period of peak growth, but decreased both N and P concentrations in the leaves of dominant plant species, likely caused by accelerated plant senescence in the warmed plots. The attenuated warming effect on CO 2 assimilation during the late growing season was associated with lowered leaf N and P concentrations. These findings suggest that warming-mediated nutrient changes may not always benefit ecosystem C uptake in permafrost regions, making our ability to predict the C balance in these warming-sensitive ecosystems more challenging than previously thought. © 2017 by the Ecological Society of America.

Mis-placed Congeniality: When Pathogens Ask Their Plant Hosts for Another Drink.

PubMed

Ding, Pingtao; Jones, Jonathan D G

2017-01-23

Plants control nutrient availability in intercellular spaces (the apoplast) via transporters, channels, and vesicular transport. Recent papers in Science and Nature from two groups have highlighted how plants control sugar to restrict bacterial growth (Yamada et al., 2016) and how increased water availability enhances pathogenesis (Xin et al., 2016). Copyright © 2017. Published by Elsevier Inc.

Comparing Nutrient Removal from Membrane Filtered and Unfiltered Domestic Wastewater Using Chlorella vulgaris

PubMed Central

Mayhead, Elyssia; Llewellyn, Carole A.; Fuentes-Grünewald, Claudio

2018-01-01

The nutrient removal efficiency of Chlorella vulgaris cultivated in domestic wastewater was investigated, along with the potential to use membrane filtration as a pre-treatment tool during the wastewater treatment process. Chlorella vulgaris was batch cultivated for 12 days in a bubble column system with two different wastewater treatments. Maximum uptake of 94.18% ammonium (NH4-N) and 97.69% ortho-phosphate (PO4-P) occurred in 0.2 μm membrane filtered primary wastewater. Membrane filtration enhanced the nutrient uptake performance of C. vulgaris by removing bacteria, protozoa, colloidal particles and suspended solids, thereby improving light availability for photosynthesis. The results of this study suggest that growing C. vulgaris in nutrient rich membrane filtered wastewater provides an option for domestic wastewater treatment to improve the quality of the final effluent. PMID:29351200

Application of agricultural biotechnology to improve food nutrition and healthcare products.

PubMed

Sun, Samuel S M

2008-01-01

Crop plants provide essential food nutrients to humans and livestock, including carbohydrates, lipids, proteins, minerals and vitamins, directly or indirectly. The level and composition of food nutrients vary significantly in different food crops. As a result, plant foods are often deficient in certain nutrient components. Relying on a single food crop as source of nutrients thus will not achieve a balanced diet and results in malnutrition and deficiency diseases, especially in the developing countries, due mainly to poverty. The development and application of biotechnology offers opportunities and novel possibilities to enhance the nutritional quality of crops, particularly when the necessary genetic variability is not available. While initial emphasis of agricultural biotechnology has been placed on input traits of crops such as herbicide tolerance, insect resistance and virus resistance, increasing effort and promising proof-of-concept products have been made in output traits including enhancing the nutritional quality of crops since 1990s. Advancements in plant transformation and transgene expression also allow the use of plants as bioreactors to produce a variety of bio-products at large scale and low cost. Many proof-of-concept plant-derived healthcare products have been generated and several commercialized.

Current understanding on ethylene signaling in plants: the influence of nutrient availability.

PubMed

Iqbal, Noushina; Trivellini, Alice; Masood, Asim; Ferrante, Antonio; Khan, Nafees A

2013-12-01

The plant hormone ethylene is involved in many physiological processes, including plant growth, development and senescence. Ethylene also plays a pivotal role in plant response or adaptation under biotic and abiotic stress conditions. In plants, ethylene production often enhances the tolerance to sub-optimal environmental conditions. This role is particularly important from both ecological and agricultural point of views. Among the abiotic stresses, the role of ethylene in plants under nutrient stress conditions has not been completely investigated. In literature few reports are available on the interaction among ethylene and macro- or micro-nutrients. However, the published works clearly demonstrated that several mineral nutrients largely affect ethylene biosynthesis and perception with a strong influence on plant physiology. The aim of this review is to revisit the old findings and recent advances of knowledge regarding the sub-optimal nutrient conditions on the effect of ethylene biosynthesis and perception in plants. The effect of deficiency or excess of the single macronutrient or micronutrient on the ethylene pathway and plant responses are reviewed and discussed. The synergistic and antagonist effect of the different mineral nutrients on ethylene plant responses is critically analyzed. Moreover, this review highlights the status of information between nutritional stresses and plant response, emphasizing the topics that should be further investigated. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Silicon availability modifies nutrient use efficiency and content, C:N:P stoichiometry, and productivity of winter wheat (Triticum aestivum L.)

NASA Astrophysics Data System (ADS)

Neu, Silke; Schaller, Jörg; Dudel, E. Gert

2017-01-01

Silicon (Si) is known as beneficial element for graminaceous plants. The importance of Si for plant functioning of cereals was recently emphasized. However, about the effect of Si availability on biomass production, grain yield, nutrient status and nutrient use efficiency for wheat (Triticum aestivum L.), as one of the most important crop plants worldwide, less is known so far. Consequently, we assessed the effect of a broad range of supply levels of amorphous SiO2 on wheat plant performance. Our results revealed that Si is readily taken up and accumulated basically in aboveground vegetative organs. Carbon (C) and phosphorus (P) status of plants were altered in response to varying Si supply. In bulk straw biomass C concentration decreased with increasing Si supply, while P concentration increased from slight limitation towards optimal nutrition. Thereby, aboveground biomass production increased at low to medium supply levels of silica whereas grain yield increased at medium supply level only. Nutrient use efficiency was improved by Si insofar that biomass production was enhanced at constant nitrogen (N) status of substrate and plants. Consequently, our findings imply fundamental influences of Si on C turnover, P availability and nitrogen use efficiency for wheat as a major staple crop.

Farming with rocks and minerals: challenges and opportunities.

PubMed

Van Straaten, Peter

2006-12-01

In many parts of the world food security is at risk. One of the biophysical root causes of falling per-capita food production is the declining quality and quantity of soils. To reverse this trend and increase soil fertility soil and plant nutrients have to be replenished. This review provides a literature survey of experiences of using multi-nutrient rock fertilizers for soil fertility enhancement from temperate and tropical environments. Advantages and limitations of the application of rock fertilizers are discussed. Examples are provided from two successful nutrient replenishment projects in Africa where locally available rock fertilizers are used on highly leached acid soils. The potential of combining organic materials alongside rock fertilizers in soil fertility replenishment strategies is stressed.

Shifting terrestrial feedbacks from CO2 fertilization to global warming

NASA Astrophysics Data System (ADS)

Peñuelas, Josep; Ciais, Philippe; Janssens, Ivan; Canadell, Josep; Obersteiner, Michael; Piao, Shilong; Vautard, Robert; Sardans Jordi Sardans, Jordi

2016-04-01

Humans are increasingly fertilizing the planet. Our activities are increasing atmospheric concentrations of carbon dioxide, nitrogen inputs to ecosystems and global temperatures. Individually and combined, they lead to biospheric availability of carbon and nitrogen, enhanced metabolic activity, and longer growing seasons. Plants can consequently grow more and take up more carbon that can be stored in ecosystem carbon pools, thus enhancing carbon sinks for atmospheric CO2. Data on the increased strength of carbon sinks are, however, inconclusive: Some data (eddy covariance, short-term experiments on elevated CO2 and nutrient fertilization) suggest that biospheric carbon uptake is already effectively increasing but some other data suggest it is not, or are not general and conclusive (tree-ring, forest inventory). The combined land-ocean CO2 sink flux per unit of excess atmospheric CO2 above preindustrial levels declined over 1959-2012 by a factor of about 1/3, implying that CO2 sinks increased more slowly than excess CO2. We will discuss the available data, and the discussion will drive us to revisit our projections for enhanced carbon sinks. We will reconsider the performance of the modulators of increased carbon uptake in a CO2 fertilized and warmed world: nutrients, climate, land use and pollution. Nutrient availability in particular plays a crucial role. A simple mass-balance approach indicates that limited phosphorus availability and the corresponding N:P imbalances can jointly reduce the projected future carbon storage by natural ecosystems during this century. We then present a new paradigm: we are shifting from a fertilization to a warming era. Compared to the historical period, future impacts of warming will be larger than the benefits of CO2 fertilization given nutrient limitations, management and disturbance (which reduces C stocks and thus sequestration potential) and because CO2 will decrease by 2050 in RCP2.6, meaning loss of CO2 fertilization, and CO2 stabilizes by 2060 in RCP4.5. So in light of the Paris agreement, it is more important to investigate climate change impacts on carbon stocks than to expect a continuation of increasing sink due to CO2 fertilization, which will have only a small role or disappear in RCP2.6 during this century.

Parasite infection alters nitrogen cycling at the ecosystem scale.

PubMed

Mischler, John; Johnson, Pieter T J; McKenzie, Valerie J; Townsend, Alan R

2016-05-01

Despite growing evidence that parasites often alter nutrient flows through their hosts and can comprise a substantial amount of biomass in many systems, whether endemic parasites influence ecosystem nutrient cycling, and which nutrient pathways may be important, remains conjectural. A framework to evaluate how endemic parasites alter nutrient cycling across varied ecosystems requires an understanding of the following: (i) parasite effects on host nutrient excretion; (ii) ecosystem nutrient limitation; (iii) effects of parasite abundance, host density, host functional role and host excretion rate on nutrient flows; and (iv) how this infection-induced nutrient flux compares to other pools and fluxes. Pathogens that significantly increase the availability of a limiting nutrient within an ecosystem should produce a measurable ecosystem-scale response. Here, we combined field-derived estimates of trematode parasite infections in aquatic snails with measurements of snail excretion and tissue stoichiometry to show that parasites are capable of altering nutrient excretion in their intermediate host snails (dominant grazers). We integrated laboratory measurements of host nitrogen excretion with field-based estimates of infection in an ecosystem model and compared these fluxes to other pools and fluxes of nitrogen as measured in the field. Eighteen nitrogen-limited ponds were examined to determine whether infection had a measurable effect on ecosystem-scale nitrogen cycling. Because of their low nitrogen content and high demand for host carbon, parasites accelerated the rate at which infected hosts excreted nitrogen to the water column in a dose-response manner, thereby shifting nutrient stoichiometry and availability at the ecosystem scale. Infection-enhanced fluxes of dissolved inorganic nitrogen were similar to other commonly important environmental sources of bioavailable nitrogen to the system. Additional field measurements within nitrogen-limited ponds indicated that nitrogen flux rates from the periphyton to the water column in high-snail density/high-infection ponds were up to 50% higher than low-infection ponds. By altering host nutrient assimilation/excretion flexibility, parasites could play a widespread, but currently unrecognized, role in ecosystem nutrient cycling, especially when parasite and host abundances are high and hosts play a central role in ecosystem nutrient cycling. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Sex-related differences in photoinhibition, photo-oxidative stress and photoprotection in stinging nettle (Urtica dioica L.) exposed to drought and nutrient deficiency.

PubMed

Simancas, Bárbara; Juvany, Marta; Cotado, Alba; Munné-Bosch, Sergi

2016-03-01

Dimorphic plant species can show distinct nutrient needs due to sex-related differences in nutrient allocation to reproductive structures, which can potentially affect their sensitivity to photoinhibition and photo-oxidative stress. Here, we investigated sex-related differences in the extent of photo-oxidative stress in male and female individuals of U. dioica exposed to a combination of severe drought and nutrient starvation. Male and female individuals of U. dioica subject to severe drought stress were exposed to various levels of nutrient availability. First, a set of plants grown under field conditions and exposed to summer drought was used to test the effects of nutrient supply (given as NPK fertilizer). Secondly, the effects of various phosphate concentrations in the nutrient solution were tested in drought-stressed potted plants. The Fv/Fm ratio (maximum efficiency of PSII photochemistry), photoprotection capacity (levels of carotenoids, including the xanthophyll cycle, and vitamins C and E), and the extent of lipid peroxidation (hydroperoxide levels) were measured. Results showed that an application of the NPK fertilizer to the soil had a positive effect on drought-stressed plants, reducing the extent of lipid peroxidation in both males and females. P deficiency led to residual photoinhibition, as indicated by significant reductions in the Fv/Fm ratio, and enhanced lipid peroxidation in females, but not in males. We conclude that (i) increased nutrient availability in the soil can alleviate photo-oxidative stress in drought-stressed U. dioica plants, and (ii) U. dioica plants show sexual secondary dimorphism in terms of photoinhibition and photo-oxidative stress, but this is only apparent when stress infringed on plants is very severe. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of enhanced loads of nutrients on epiphytes on leaves and rhizomes of Posidonia oceanica

NASA Astrophysics Data System (ADS)

Balata, David; Piazzi, Luigi; Nesti, Ugo; Bulleri, Fabio; Bertocci, Iacopo

2010-04-01

The increase of anthropogenic activities has severely altered both terrestrial and aquatic systems. Urbanisation, excessive use of agricultural fertilisers, organic runoff and climate change have caused an increase of nutrients in coastal waters, altering the diversity and food-web structure of benthic assemblages. The aims of the present paper were to text if an experimentally increased availability of nutrients, primarily nitrogen and phosphorous, in an oligotrophic basin, would affect epiphytic assemblages on leaves and rhizomes of P. oceanica and whether this could change rates of consumption of the plant by herbivores. In particular, we tested the hypothesis i) that changes to species composition and abundance of epiphytic assemblages generated by nutrients enrichment would vary between leaves and rhizomes and that ii) alterations to epiphytic assemblages on leaves might, in turn, modify feeding rates of herbivorous fish. After two years, the structure of both leaf and rhizome epiphytic assemblages responded to changes in nutrient concentrations before the occurrence of drastic alterations to the host plant, but only the former showed significant changes in terms of species composition. Moreover, a larger intensity of grazing on P. oceanica leaves was documented in experimentally enriched areas than in controls. The present findings and conclusions are applicable to other systems where patterns of biodiversity depend on changes in the availability of nutrients due to natural or anthropogenic events, likely interacting with biological processes, such as competition and grazing.

Microwave enhanced oxidation treatment of organic fertilizers.

PubMed

More, Abhilasha; Srinivasan, Asha; Liao, Ping Huang; Lo, Kwang Victor

2017-08-01

Liquid organic fertilizers (LOFs) are relatively easier to degrade than those of solid organic fertilizers, and the nutrients are readily available for plant uptake. Microwave enhanced advanced oxidation treatment (MW/H 2 O 2 -AOP) was used to convert solid organic fertilizers (insoluble blood meal, bone meal, feather meal, sunflower ash and a mixture) into LOF. After the MW/H 2 O 2 -AOP treatment, high soluble nitrogen (11-29%), soluble phosphorus (64%) and potassium (92%), as well as low total suspended solids content could be obtained. The resulting LOF would make the nutrients more bioavailable, and would provide some of them for the plant uptake immediately. Temperature and hydrogen peroxide dosage were found to be significant factors affecting nitrogen release from blood meal and feather meal, while temperature and pH were found to be significant factors for solubilizing phosphorus and potassium from bone meal and ash, respectively. The MW/H 2 O 2 -AOP reduced suspended solids, and released nutrients into solution; therefore, it was an effective treatment method to make LOFs. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Differential sensitivity of spinach and amaranthus to enhanced UV-B at varying soil nutrient levels: association with gas exchange, UV-B-absorbing compounds and membrane damage.

PubMed

Singh, Suruchi; Agrawal, Madhoolika; Agrawal, S B

2013-07-01

The metabolic reasons associated with differential sensitivity of C3 and C4 plant species to enhanced UV-B under varying soil nutrient levels are not well understood. In the present study, spinach (Spinacia oleracea L. var All Green), a C3 and amaranthus (Amaranthus tricolor L. var Pusa Badi Chaulai), a C4 plant were subjected to enhanced UV-B (280-315 nm; 7.2 kJ m(-2) day(-1)) over ambient under varying soil nutrient levels. The nutrient amendments were recommended Nitrogen (N), Phosphorus (P), Potassium (K), 1.5× recommended NPK, 1.5× recommended N and 1.5× recommended K. Enhanced UV-B negatively affected both the species at all nutrient levels, but the reductions varied with nutrient concentration and combinations. Reductions in photosynthetic rate, stomatal conductance and chlorophyll content were significantly more in spinach compared with amaranthus. The reduction in photosynthetic rate was maximum at 1.5× recommended K and minimum in 1.5× NPK amended plants. The oxidative damage to membranes measured in terms of malondialdehyde content was significantly higher in spinach compared with amaranthus. Enhanced UV-B reduced SOD activity in both the plants except in amaranthus at 1.5× recommended K. POX activity increased under enhanced UV-B at all nutrient levels in amaranthus, but only at 1.5× K in spinach. Amaranthus had significantly higher UV-B-absorbing compounds than spinach even under UV-B stress. Lowest reductions in yield and total biomass under enhanced UV-B compared with ambient were observed in amaranthus grown at 1.5× recommended NPK. Enhanced UV-B did not significantly change the nitrogen use efficiency in amaranthus at all NPK levels, but reduced in spinach except at 1.5× K. These findings suggest that the differential sensitivity of the test species under enhanced UV-B at varying nutrient levels is due to varying antioxidative and UV-B screening capacity, and their ability to utilize nutrients. Amaranthus tolerated enhanced UV-B stress more than spinach at all nutrient levels and 1.5× recommended NPK lowered the sensitivity maximally to enhanced UV-B with respect to photosynthesis, biomass and yield. PCA score has also confirmed the lower sensitivity of amaranthus compared with spinach with respect to the measured physiological and biochemical parameters.

Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees

PubMed Central

Chen, Weile; Koide, Roger T.; Adams, Thomas S.; DeForest, Jared L.; Cheng, Lei; Eissenstat, David M.

2016-01-01

Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich “hotspots” can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together. PMID:27432986

Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees.

PubMed

Chen, Weile; Koide, Roger T; Adams, Thomas S; DeForest, Jared L; Cheng, Lei; Eissenstat, David M

2016-08-02

Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich "hotspots" can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together.

The relative importance of light and nutrient limitation of phytoplankton growth: A simple index of coastal ecosystem sensitivity to nutrient enrichment

USGS Publications Warehouse

Cloern, J.E.

1999-01-01

Anthropogenic nutrient enrichment of the coastal zone is now a well-established fact. However, there is still uncertainty about the mechanisms through which nutrient enrichment can disrupt biological communities and ecosystem processes in the coastal zone. For example, while some estuaries exhibit classic symptoms of acute eutrophication, including enhanced production of algal biomass, other nutrient-rich estuaries maintain low algal biomass and primary production. This implies that large differences exist among coastal ecosystems in the rates and patterns of nutrient assimilation and cycling. Part of this variability comes from differences among ecosystems in the other resource that can limit algal growth and production - the light energy required for photosynthesis. Complete understanding of the eutrophication process requires consideration of the interacting effects of light and nutrients, including the role of light availability as a regulator of the expression of eutrophication. A simple index of the relative strength of light and nutrient limitation of algal growth can be derived from models that describe growth rate as a function of these resources. This index can then be used as one diagnostic to classify the sensitivity of coastal ecosystems to the harmful effects of eutrophication. Here I illustrate the application of this diagnostic with light and nutrient measurements made in three California estuaries and two Dutch estuaries.

Role of nutrients and illuminance in predicting the fate of fungal mediated petroleum hydrocarbon degradation and biomass production.

PubMed

Ali Khan, Aqib Hassan; Tanveer, Sundus; Anees, Mariam; Muhammad, Yousaf Shad; Iqbal, Mazhar; Yousaf, Sohail

2016-07-01

Biodegradation and biomass production are affected by numerous environmental factors including pH, oxygen availability and presence of pollutants. The present study, for the first time, elucidated the effects of nutrients and light on mycodegradation of petroleum hydrocarbons in diesel oil. Seven fungal strains (Aspergillus terreus FA3, Aspergillus niger FA5, Aspergillus terreus FA6, Penicillium chrysogenum FP4, Aspergillus terreus FP6, Aspergillus flavus FP10, and Candida sp. FG1) were used for hydrocarbon degradation under static conditions, in four combinations of nutrient media and illuminance for 45 days. Highest degradation was achieved by Aspergillus terreus FA6 and Candida sp. FG1 under both conditions of light and dark, with nutrient deprived HAF (Hydrocarbon adopted fungi) broth. Under HAF/Dark diesel oil degradation by FA6 and FG1 was 87.3% and 84.3% respectively, while under HAF/Light both FA6 and FG1 performed 84.3% biodegradation. The highest biomass was produced by Aspergillus flavus FP10 in PDB (Potato dextrose broth)/Dark (109.3 mg). Fungal degradation of petroleum hydrocarbons was negatively affected by the presence of other simpler-to-degrade carbon sources in the medium. The biomass production was enhanced by improved nutrient availability and diminished by illuminance. Copyright © 2016 Elsevier Ltd. All rights reserved.

High nutrient availability reduces the diversity and stability of the equine caecal microbiota

PubMed Central

Hansen, Naja C. K.; Avershina, Ekaterina; Mydland, Liv T.; Næsset, Jon A.; Austbø, Dag; Moen, Birgitte; Måge, Ingrid; Rudi, Knut

2015-01-01

Background It is well known that nutrient availability can alter the gut microbiota composition, while the effect on diversity and temporal stability remains largely unknown. Methods Here we address the equine caecal microbiota temporal stability, diversity, and functionality in response to diets with different levels of nutrient availability. Hay (low and slower nutrient availability) versus a mixture of hay and whole oats (high and more rapid nutrient availability) were used as experimental diets. Results We found major effects on the microbiota despite that the caecal pH was far from sub-clinical acidosis. We found that the low nutrient availability diet was associated with a higher level of both diversity and temporal stability of the caecal microbiota than the high nutrient availability diet. These observations concur with general ecological theories, suggesting a stabilising effect of biological diversity and that high nutrient availability has a destabilising effect through reduced diversity. Conclusion Nutrient availability does not only change the composition but also the ecology of the caecal microbiota. PMID:26246403

On nutrients and trace metals: Effects from Enhanced Weathering

NASA Astrophysics Data System (ADS)

Amann, T.; Hartmann, J.

2015-12-01

The application of rock flour on suitable land ("Enhanced Weathering") is one proposed strategy to reduce the increase of atmospheric CO2 concentrations. At the same time it is an old and established method to add fertiliser and influence soil properties. Investigations of this method focused on the impact on the carbonate system, as well as on engineering aspects of a large-scale application, but potential side effects were never discussed quantitatively. We analysed about 120,000 geochemically characterised volcanic rock samples from the literature. Applying basic statistics, theoretical release rates of nutrients and potential contaminants by Enhanced Weathering were evaluated for typical rock types. Applied rock material can contain significant amounts of essential or beneficial nutrients (potassium, phosphorus, micronutrients). Their release can partly cover the demand of major crops like wheat, rice or corn, thereby increasing crop yield on degraded soils. However, the concentrations of considered elements are variable within a specific rock type, depending on the geological setting. High heavy metal concentrations are found in (ultra-) basic rocks, the class with the highest CO2 drawdown potential. More acidic rocks contain less or no critical amounts, but sequester less CO2. Findings show that the rock selection determines the capability to supply significant amounts of nutrients, which could partly substitute industrial mineral fertiliser usage. At the same time, the release of harmful trace element has to be considered. Through careful selection of regionally available rocks, benefits could be maximised and drawbacks reduced. The deployment of Enhanced Weathering to sequester CO2 and to ameliorate soils necessitates an ecosystem management, considering the release and fate of weathered elements in plants, soils and water. Cropland with degraded soils would benefit while having a net negative CO2 effect, while other carbon dioxide removal strategies, like afforestation, biofuel production, and biochar application could benefit from Enhanced Weathering side effects, as organic carbon pools are positively influenced.

Crop response to deep tillage - a meta-analysis

NASA Astrophysics Data System (ADS)

Schneider, Florian; Don, Axel; Hennings, Inga; Schmittmann, Oliver; Seidel, Sabine J.

2017-04-01

Subsoil, i.e. the soil layer below the topsoil, stores tremendous stocks of nutrients and can keep water even under drought conditions. Deep tillage may be a method to enhance the plant-availability of subsoil resources. However, in field trials, deep tillage effects on crop yields were inconsistent. Therefore, we conducted a meta-analysis of crop yield response to subsoiling, deep ploughing and deep mixing of soil profiles. Our search resulted in 1530 yield comparisons following deep and conventional control tillage on 67 experimental cropping sites. The vast majority of the data derived from temperate latitudes, from trials conducted in the USA (679 observations) and Germany (630 observations). On average, crop yield response to deep tillage was slightly positive (6% increase). However, individual deep tillage effects were highly scattered including about 40% yield depressions after deep tillage. Deep tillage on soils with root restrictive layers increased crop yields about 20%, while soils containing >70% silt increased the risk of yield depressions following deep tillage. Generally, deep tillage effects increased with drought intensity indicating deep tillage as climate adaptation measure at certain sites. Our results suggest that deep tillage can facilitate the plant-availability of subsoil nutrients, which increases crop yields if (i) nutrients in the topsoil are growth limiting, and (ii) deep tillage does not come at the cost of impairing topsoil fertility. On sites with root restrictive soil layers, deep tillage can be an effective measure to mitigate drought stress and improve the resilience of crops. However, deep tillage should only be performed on soils with a stable structure, i.e. <70% silt content. We will discuss the contribution of deep tillage options to enhance the sustainability of agricultural production by facilitating the uptake of nutrients and water from the subsoil.

Irrigation and weed control alter soil microbiology and nutrient availability in North Carolina Sandhill peach orchards.

PubMed

Zhang, Yi; Wang, Liangju; Yuan, Yongge; Xu, Jing; Tu, Cong; Fisk, Connie; Zhang, Weijian; Chen, Xin; Ritchie, David; Hu, Shuijin

2018-02-15

Orchard management practices such as weed control and irrigation are primarily aimed at maximizing fruit yields and economic profits. However, the impact of these practices on soil fertility and soil microbiology is often overlooked. We conducted a two-factor experimental manipulation of weed control by herbicide and trickle irrigation in a nutrient-poor peach (Prunus persica L. cv. Contender) orchard near Jackson Springs, North Carolina. After three and eight years of treatments, an array of soil fertility parameters were examined, including soil pH, soil N, P and cation nutrients, microbial biomass and respiration, N mineralization, and presence of arbuscular mycorrhizal fungi (AMF). Three general trends emerged: 1) irrigation significantly increased soil microbial biomass and activity, 2) infection rate of mycorrhizal fungi within roots were significantly higher under irrigation than non-irrigation treatments, but no significant difference in the AMF community composition was detected among treatments, 3) weed control through herbicides reduced soil organic matter, microbial biomass and activity, and mineral nutrients, but had no significant impacts on root mycorrhizal infection and AMF communities. Weed-control treatments directly decreased availability of soil nutrients in year 8, especially soil extractable inorganic N. Weed control also appears to have altered the soil nutrients via changes in soil microbes and altered net N mineralization via changes in soil microbial biomass and activity. These results indicate that long-term weed control using herbicides reduces soil fertility through reducing organic C inputs, nutrient retention and soil microbes. Together, these findings highlight the need for alternative practices such as winter legume cover cropping that maintain and/or enhance organic inputs to sustain the soil fertility. Copyright © 2017 Elsevier B.V. All rights reserved.

Can observed ecosystem responses to elevated CO2 and N fertilisation be explained by optimal plant C allocation?

NASA Astrophysics Data System (ADS)

Stocker, Benjamin; Prentice, I. Colin

2016-04-01

The degree to which nitrogen availability limits the terrestrial C sink under rising CO2 is a key uncertainty in carbon cycle and climate change projections. Results from ecosystem manipulation studies and meta-analyses suggest that plant C allocation to roots adjusts dynamically under varying degrees of nitrogen availability and other soil fertility parameters. In addition, the ratio of biomass production to GPP appears to decline under nutrient scarcity. This reflects increasing plant C export into the soil and to symbionts (Cex) with decreasing nutrient availability. Cex is consumed by an array of soil organisms and may imply an improvement of nutrient availability to the plant. These concepts are left unaccounted for in Earth system models. We present a model for the coupled cycles of C and N in grassland ecosystems to explore optimal plant C allocation under rising CO2 and its implications for the ecosystem C balance. The model follows a balanced growth approach, accounting for the trade-offs between leaf versus root growth and Cex in balancing C fixation and N uptake. We further model a plant-controlled rate of biological N fixation (BNF) by assuming that Cex is consumed by N2-fixing processes if the ratio of Nup:Cex falls below the inverse of the C cost of N2-fixation. The model is applied at two temperate grassland sites (SwissFACE and BioCON), subjected to factorial treatments of elevated CO2 (FACE) and N fertilization. Preliminary simulation results indicate initially increased N limitation, evident by increased relative allocation to roots and Cex. Depending on the initial state of N availability, this implies a varying degree of aboveground growth enhancement, generally consistent with observed responses. On a longer time scale, ecosystems are progressively released from N limitation due tighter N cycling. Allowing for plant-controlled BNF implies a quicker release from N limitation and an adjustment to more open N cycling. In both cases, optimal plant C allocation implies a sustained growth enhancement but a decreased ratio of biomass productivity to GPP. Flexible allocation, C cost of N uptake, and flexible N retention imply plant control on N availability. Thereby, plant control on BNF is essential to determine the ultimate growth enhancement under elevated CO2 and whether this implies higher N losses and N2O emissions.

Surface Nutrient Utilisation and Productivity During Glacial-Interglacial Periods from the Equatorial Indian Ocean

NASA Astrophysics Data System (ADS)

R, C. K.; Bhushan, R.; Agnihotri, R.; Sawlani, R.; Jull, A. J. T.

2016-12-01

Seawaters and underlying sediments off Sri Lanka provide a unique marine realm affected by both branches of Northern Indian Ocean i.e. Arabian Sea (AS) and Bay of Bengal (BOB). AS and BOB are known for their distinct response to southwest monsoon. AS experiencing mainly winds and upwelling while BOB receives precipitation driven surface runoff from the Indian sub-continent. Multiple proxies were measured on a radiocarbon dated sediment core raised off Sri Lanka; their down core variations were used to understand oceanic history (nutrient utilisation, surface productivity, nature of organic matter) spanning last glacial-interglacial cycle ( 26 to 2.5 ka BP). Variations in CaCO3, biogenic silica (BSi) and δ15N from 26 ka to 12.5 ka BP indicate the region was experiencing high surface productivity with probably reduced surface nutrient utilisation efficiency. Sedimentary δ15N depth profile is decoupled from down core variations of major productivity indices (e.g. CaCO3, OC), hinting plausibly partial utilization of nutrients in the mixed layer (photic zone). δ13C of OC and C/N (wt. ratio) clearly reveal the terrestrial origin of organic matter at 15 ka BP, a period known for witnessing onset of deglaciation in northern hemisphere. δ13C minimum at 9 ka BP indicates intense monsoonal activity during this time coinciding well with solar insolation (June) maximum of the northern hemisphere. With the onset of Holocene ( 11 ka BP), δ15N variations appear to correlate with BSi and Ba/Ti indicating enhanced utilization of available nutrients at surface. Suggesting surface productivity over the region was probably micro-nutrient limited. The increased inventory of terrestrial runoff in Holocene probably demonstrates enhanced carbon sequestration capability of the region.

Does the combination of biochar and clinoptilolite enhance nutrient recovery from the liquid fraction of biogas digestate?

PubMed

Kocatürk-Schumacher, Nazlı Pelin; Zwart, Kor; Bruun, Sander; Brussaard, Lijbert; Jensen, Lars Stoumann

2017-05-01

Concentrating nutrients on biochar and clinoptilolite and subsequently using the nutrient-enriched sorbents as a fertiliser could be an alternative way to manage nutrients in digestate. In this study, we investigated the use of biochar and clinoptilolite columns in removing ammonium, potassium, orthophosphate and dissolved organic carbon (DOC) from the liquid fraction of digestate. Our objectives were to investigate the effect of the initial loading ratio between liquid and biochar on nutrient removal, and to investigate the effect of combining biochar with clinoptilolite on nutrient and DOC removal efficiency. Increasing the initial loading ratios increased nutrient concentrations on biochar to 8.61 mg NH 4 -N g -1 , 1.95 mg PO 4 -P g -1 and 13.01 mg DOC g -1 , but resulted in decreasing removal efficiencies. The combination of biochar and clinoptilolite resulted in improved ammonium, potassium and DOC removal efficiencies compared to biochar alone, but did not significantly change PO 4 -P removal efficiencies. Removal efficiencies with combined sorbents were up to 67% for ammonium, 58% for DOC and 58% for potassium. Clinoptilolite showed higher removal efficiencies compared to biochar alone, and combining clinoptilolite with biochar improved only total P removal efficiency. Concentrating nutrients with clinoptilolite and biochar may be an option when both sorbents are available at low cost.

Yield and Water Quality Impacts of Field-Scale Integration of Willow into a Continuous Corn Rotation System.

PubMed

Zumpf, Colleen; Ssegane, Herbert; Negri, Maria Cristina; Campbell, Patty; Cacho, Julian

2017-07-01

Agricultural landscape design has gained recognition by the international environmental and development community as a strategy to address multiple goals in land, water, and ecosystem service management; however, field research is needed to quantify impacts on specific local environments. The production of bioenergy crops in specific landscape positions within a grain-crop field can serve the dual purpose of producing cellulosic biomass (nutrient recovery) while also providing regulating ecosystem services to improve water quality (nutrient reduction). The effectiveness of such a landscape design was evaluated by the strategic placement of a 0.8-ha short-rotation shrub willow ( Seemen) bioenergy buffer along marginal soils in a 6.5-ha corn ( L.) field in a 6-yr field study in central Illinois. The impact of willow integration on water quality (soil water, shallow groundwater leaching, and crop nutrient uptake) and quantity (soil moisture and transpiration) was monitored in comparison with corn in the willow's first cycle of growth. Willows significantly reduced nitrate leachate in shallow subsurface water by 88% while maintaining adequate nutrient and water usage. Results suggest that willows offer an efficient nutrient-reduction strategy and may provide additional ecosystem services and benefits, including enhanced soil health. However, low values for calculated willow biomass will need to be readdressed in the future as harvest data become available to understand contributing factors that affected productivity beyond nutrient availability. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Root Traits and Phenotyping Strategies for Plant Improvement

PubMed Central

Paez-Garcia, Ana; Motes, Christy M.; Scheible, Wolf-Rüdiger; Chen, Rujin; Blancaflor, Elison B.; Monteros, Maria J.

2015-01-01

Roots are crucial for nutrient and water acquisition and can be targeted to enhance plant productivity under a broad range of growing conditions. A current challenge for plant breeding is the limited ability to phenotype and select for desirable root characteristics due to their underground location. Plant breeding efforts aimed at modifying root traits can result in novel, more stress-tolerant crops and increased yield by enhancing the capacity of the plant for soil exploration and, thus, water and nutrient acquisition. Available approaches for root phenotyping in laboratory, greenhouse and field encompass simple agar plates to labor-intensive root digging (i.e., shovelomics) and soil boring methods, the construction of underground root observation stations and sophisticated computer-assisted root imaging. Here, we summarize root architectural traits relevant to crop productivity, survey root phenotyping strategies and describe their advantages, limitations and practical value for crop and forage breeding programs. PMID:27135332

Root Traits and Phenotyping Strategies for Plant Improvement.

PubMed

Paez-Garcia, Ana; Motes, Christy M; Scheible, Wolf-Rüdiger; Chen, Rujin; Blancaflor, Elison B; Monteros, Maria J

2015-06-15

Roots are crucial for nutrient and water acquisition and can be targeted to enhance plant productivity under a broad range of growing conditions. A current challenge for plant breeding is the limited ability to phenotype and select for desirable root characteristics due to their underground location. Plant breeding efforts aimed at modifying root traits can result in novel, more stress-tolerant crops and increased yield by enhancing the capacity of the plant for soil exploration and, thus, water and nutrient acquisition. Available approaches for root phenotyping in laboratory, greenhouse and field encompass simple agar plates to labor-intensive root digging (i.e., shovelomics) and soil boring methods, the construction of underground root observation stations and sophisticated computer-assisted root imaging. Here, we summarize root architectural traits relevant to crop productivity, survey root phenotyping strategies and describe their advantages, limitations and practical value for crop and forage breeding programs.

Endangered Right Whales Enhance Primary Productivity in the Bay of Fundy

PubMed Central

Roman, Joe; Nevins, John; Altabet, Mark; Koopman, Heather; McCarthy, James

2016-01-01

Marine mammals have recently been documented as important facilitators of rapid and efficient nutrient recycling in coastal and offshore waters. Whales enhance phytoplankton nutrition by releasing fecal plumes near the surface after feeding and by migrating from highly productive, high-latitude feeding areas to low-latitude nutrient-poor calving areas. In this study, we measured NH4+ and PO43- release rates from the feces of North Atlantic right whales (Eubalaena glacialis), a highly endangered baleen whale. Samples for this species were primarily collected by locating aggregations of whales in surface-active groups (SAGs), which typically consist of a central female surrounded by males competing for sexual activity. When freshly collected feces were incubated in seawater, high initial rates of N release were generally observed, which decreased to near zero within 24 hours of sampling, a pattern that is consistent with the active role of gut microflora on fecal particles. We estimate that at least 10% of particulate N in whale feces becomes available as NH4+ within 24 hours of defecation. Phosphorous was also abundant in fecal samples: initial release rates of PO43- were higher than for NH4+, yielding low N/P nutrient ratios over the course of our experiments. The rate of PO43- release was thus more than sufficient to preclude the possibility that nitrogenous nutrients supplied by whales would lead to phytoplankton production limited by P availability. Phytoplankton growth experiments indicated that NH4+ released from whale feces enhance productivity, as would be expected, with no evidence that fecal metabolites suppress growth. Although North Atlantic right whales are currently rare (approximately 450 individuals), they once numbered about 14,000 and likely played a substantial role in recycling nutrients in areas where they gathered to feed and mate. Even though the NH4+ released from fresh whale fecal material is a small fraction of total whale fecal nitrogen, and recognizing the fact that the additional nitrogen released in whale urine would be difficult to measure in a field study, the results of this study support the idea that the distinctive isotopic signature of the released NH4+ could be used to provide a conservative estimate of the contribution of the whale pump to primary productivity in coastal regions where whales congregate. PMID:27331902

Endangered Right Whales Enhance Primary Productivity in the Bay of Fundy.

PubMed

Roman, Joe; Nevins, John; Altabet, Mark; Koopman, Heather; McCarthy, James

2016-01-01

Marine mammals have recently been documented as important facilitators of rapid and efficient nutrient recycling in coastal and offshore waters. Whales enhance phytoplankton nutrition by releasing fecal plumes near the surface after feeding and by migrating from highly productive, high-latitude feeding areas to low-latitude nutrient-poor calving areas. In this study, we measured NH4+ and PO43- release rates from the feces of North Atlantic right whales (Eubalaena glacialis), a highly endangered baleen whale. Samples for this species were primarily collected by locating aggregations of whales in surface-active groups (SAGs), which typically consist of a central female surrounded by males competing for sexual activity. When freshly collected feces were incubated in seawater, high initial rates of N release were generally observed, which decreased to near zero within 24 hours of sampling, a pattern that is consistent with the active role of gut microflora on fecal particles. We estimate that at least 10% of particulate N in whale feces becomes available as NH4+ within 24 hours of defecation. Phosphorous was also abundant in fecal samples: initial release rates of PO43- were higher than for NH4+, yielding low N/P nutrient ratios over the course of our experiments. The rate of PO43- release was thus more than sufficient to preclude the possibility that nitrogenous nutrients supplied by whales would lead to phytoplankton production limited by P availability. Phytoplankton growth experiments indicated that NH4+ released from whale feces enhance productivity, as would be expected, with no evidence that fecal metabolites suppress growth. Although North Atlantic right whales are currently rare (approximately 450 individuals), they once numbered about 14,000 and likely played a substantial role in recycling nutrients in areas where they gathered to feed and mate. Even though the NH4+ released from fresh whale fecal material is a small fraction of total whale fecal nitrogen, and recognizing the fact that the additional nitrogen released in whale urine would be difficult to measure in a field study, the results of this study support the idea that the distinctive isotopic signature of the released NH4+ could be used to provide a conservative estimate of the contribution of the whale pump to primary productivity in coastal regions where whales congregate.

Soil bacterial and fungal diversity differently correlated with soil biochemistry in alpine grassland ecosystems in response to environmental changes.

PubMed

Zhang, Yong; Dong, Shikui; Gao, Qingzhu; Liu, Shiliang; Ganjurjav, Hasbagan; Wang, Xuexia; Su, Xukun; Wu, Xiaoyu

2017-03-06

To understand effects of soil microbes on soil biochemistry in alpine grassland ecosystems under environmental changes, we explored relationships between soil microbial diversity and soil total nitrogen, organic carbon, available nitrogen and phosphorus, soil microbial biomass and soil enzyme activities in alpine meadow, alpine steppe and cultivated grassland on the Qinghai-Tibetan plateau under three-year warming, enhanced precipitation and yak overgrazing. Soil total nitrogen, organic carbon and NH 4 -N were little affected by overgrazing, warming or enhanced precipitation in three types of alpine grasslands. Soil microbial biomass carbon and phosphorus along with the sucrase and phosphatase activities were generally stable under different treatments. Soil NO 3 -N, available phosphorus, urease activity and microbial biomass nitrogen were increased by overgrazing in the cultivated grassland. Soil bacterial diversity was positively correlated with, while soil fungal diversity negatively with soil microbial biomass and enzyme activities. Soil bacterial diversity was negatively correlated with, while soil fungal diversity positively with soil available nutrients. Our findings indicated soil bacteria and fungi played different roles in affecting soil nutrients and microbiological activities that might provide an important implication to understand why soil biochemistry was generally stable under environmental changes in alpine grassland ecosystems.

Soil bacterial and fungal diversity differently correlated with soil biochemistry in alpine grassland ecosystems in response to environmental changes

NASA Astrophysics Data System (ADS)

Zhang, Yong; Dong, Shikui; Gao, Qingzhu; Liu, Shiliang; Ganjurjav, Hasbagan; Wang, Xuexia; Su, Xukun; Wu, Xiaoyu

2017-03-01

To understand effects of soil microbes on soil biochemistry in alpine grassland ecosystems under environmental changes, we explored relationships between soil microbial diversity and soil total nitrogen, organic carbon, available nitrogen and phosphorus, soil microbial biomass and soil enzyme activities in alpine meadow, alpine steppe and cultivated grassland on the Qinghai-Tibetan plateau under three-year warming, enhanced precipitation and yak overgrazing. Soil total nitrogen, organic carbon and NH4-N were little affected by overgrazing, warming or enhanced precipitation in three types of alpine grasslands. Soil microbial biomass carbon and phosphorus along with the sucrase and phosphatase activities were generally stable under different treatments. Soil NO3-N, available phosphorus, urease activity and microbial biomass nitrogen were increased by overgrazing in the cultivated grassland. Soil bacterial diversity was positively correlated with, while soil fungal diversity negatively with soil microbial biomass and enzyme activities. Soil bacterial diversity was negatively correlated with, while soil fungal diversity positively with soil available nutrients. Our findings indicated soil bacteria and fungi played different roles in affecting soil nutrients and microbiological activities that might provide an important implication to understand why soil biochemistry was generally stable under environmental changes in alpine grassland ecosystems.

Soil bacterial and fungal diversity differently correlated with soil biochemistry in alpine grassland ecosystems in response to environmental changes

PubMed Central

Zhang, Yong; Dong, Shikui; Gao, Qingzhu; Liu, Shiliang; Ganjurjav, Hasbagan; Wang, Xuexia; Su, Xukun; Wu, Xiaoyu

2017-01-01

To understand effects of soil microbes on soil biochemistry in alpine grassland ecosystems under environmental changes, we explored relationships between soil microbial diversity and soil total nitrogen, organic carbon, available nitrogen and phosphorus, soil microbial biomass and soil enzyme activities in alpine meadow, alpine steppe and cultivated grassland on the Qinghai-Tibetan plateau under three-year warming, enhanced precipitation and yak overgrazing. Soil total nitrogen, organic carbon and NH4-N were little affected by overgrazing, warming or enhanced precipitation in three types of alpine grasslands. Soil microbial biomass carbon and phosphorus along with the sucrase and phosphatase activities were generally stable under different treatments. Soil NO3-N, available phosphorus, urease activity and microbial biomass nitrogen were increased by overgrazing in the cultivated grassland. Soil bacterial diversity was positively correlated with, while soil fungal diversity negatively with soil microbial biomass and enzyme activities. Soil bacterial diversity was negatively correlated with, while soil fungal diversity positively with soil available nutrients. Our findings indicated soil bacteria and fungi played different roles in affecting soil nutrients and microbiological activities that might provide an important implication to understand why soil biochemistry was generally stable under environmental changes in alpine grassland ecosystems. PMID:28262753

Flower litters of alpine plants affect soil nitrogen and phosphorus rapidly in the eastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wang, Jinniu; Xu, Bo; Wu, Yan; Gao, Jing; Shi, Fusun

2016-10-01

Litters of reproductive organs have rarely been studied despite their role in allocating nutrients for offspring reproduction. This study determines the mechanism through which flower litters efficiently increase the available soil nutrient pool. Field experiments were conducted to collect plant litters and calculate biomass production in an alpine meadow of the eastern Tibetan Plateau. C, N, P, lignin, cellulose content, and their relevant ratios of litters were analyzed to identify their decomposition features. A pot experiment was performed to determine the effects of litter addition on the soil nutrition pool by comparing the treated and control samples. The litter-bag method was used to verify decomposition rates. The flower litters of phanerophyte plants were comparable with non-flower litters. Biomass partitioning of other herbaceous species accounted for 10-40 % of the aboveground biomass. Flower litter possessed significantly higher N and P levels but less C / N, N / P, lignin / N, and lignin and cellulose concentrations than leaf litter. The litter-bag experiment confirmed that the flower litters of Rhododendron przewalskii and Meconopsis integrifolia decompose approximately 3 times faster than mixed litters within 50 days. Pot experiment findings indicated that flower litter addition significantly increased the available nutrient pool and soil microbial productivity. The time of litter fall significantly influenced soil available N and P, and soil microbial biomass. Flower litters fed the soil nutrition pool and influenced nutrition cycling in alpine ecosystems more efficiently because of their non-ignorable production, faster decomposition rate, and higher nutrient contents compared with non-flower litters. The underlying mechanism can enrich nutrients, which return to the soil, and non-structural carbohydrates, which feed and enhance the transitions of soil microorganisms.

Considerations in planning vegan diets: children.

PubMed

Messina, V; Mangels, A R

2001-06-01

This article reviews research on the growth and nutrient intake of vegan children and provides guidelines for counselling parents of vegan children. Although diets of vegan children meet or exceed recommendations for most nutrients, and vegan children have higher intakes of fiber and lower intakes of total fat, saturated fat, and cholesterol than omnivore children, some studies indicate that they may be low in calcium. In addition, bioavailability of zinc and iron from plant foods can be low. Protein needs are slightly higher for vegan children but are easily met with a varied diet that provides adequate energy. Special attention should be given to dietary practices that enhance absorption of zinc and iron from plant foods. Further, good sources of the omega-3 fatty acid linolenic acid should be emphasized to enhance synthesis of the long-chain fatty acid docosahexanoic acid. Dietetics professionals who counsel vegan families should help parents identify good sources of vitamin B-12, riboflavin, zinc, calcium and, if sun exposure is not adequate, vitamin D. This should not be problematic, due to the growing number and availability of fortified vegan foods that can help children meet all nutrient needs. Therefore, with appropriate food choices, vegan diets can be adequate for children at all ages.

Analogous nutrient limitations in unicellular diazotrophs and Prochlorococcus in the South Pacific Ocean.

PubMed

Moisander, Pia H; Zhang, Ruifeng; Boyle, Edward A; Hewson, Ian; Montoya, Joseph P; Zehr, Jonathan P

2012-04-01

Growth limitation of phytoplankton and unicellular nitrogen (N(2)) fixers (diazotrophs) were investigated in the oligotrophic Western South Pacific Ocean. Based on change in abundances of nifH or 23S rRNA gene copies during nutrient-enrichment experiments, the factors limiting net growth of the unicellular diazotrophs UCYN-A (Group A), Crocosphaera watsonii, γ-Proteobacterium 24774A11, and the non-diazotrophic picocyanobacterium Prochlorococcus, varied within the region. At the westernmost stations, numbers were enhanced by organic carbon added as simple sugars, a combination of iron and an organic chelator, or iron added with phosphate. At stations nearest the equator, the nutrient-limiting growth was not apparent. Maximum net growth rates for UCYN-A, C. watsonii and γ-24774A11 were 0.19, 0.61 and 0.52 d(-1), respectively, which are the first known empirical growth rates reported for the uncultivated UCYN-A and the γ-24774A11. The addition of N enhanced total phytoplankton biomass up to 5-fold, and the non-N(2)-fixing Synechococcus was among the groups that responded favorably to N addition. Nitrogen was the major nutrient-limiting phytoplankton biomass in the Western South Pacific Ocean, while availability of organic carbon or iron and organic chelator appear to limit abundances of unicellular diazotrophs. Lack of phytoplankton response to nutrient additions in the Pacific warm pool waters suggests diazotroph growth in this area is controlled by different factors than in the higher latitudes, which may partially explain previously observed variability in community composition in the region.

Impact of Salt and Nutrient Content on Biofilm Formation by Vibrio fischeri.

PubMed

Marsden, Anne E; Grudzinski, Kevin; Ondrey, Jakob M; DeLoney-Marino, Cindy R; Visick, Karen L

2017-01-01

Vibrio fischeri, a marine bacterium and symbiont of the Hawaiian bobtail squid Euprymna scolopes, depends on biofilm formation for successful colonization of the squid's symbiotic light organ. Here, we investigated if culture conditions, such as nutrient and salt availability, affect biofilm formation by V. fischeri by testing the formation of wrinkled colonies on solid media. We found that V. fischeri forms colonies with more substantial wrinkling when grown on the nutrient-dense LBS medium containing NaCl relative to those formed on the more nutrient-poor, seawater-salt containing SWT medium. The presence of both tryptone and yeast extract was necessary for the production of "normal" wrinkled colonies; when grown on tryptone alone, the colonies displayed a divoting phenotype and were attached to the agar surface. We also found that the type and concentration of specific seawater salts influenced the timing of biofilm formation. Of the conditions assayed, wrinkled colony formation occurred earliest in LBS(-Tris) media containing 425 mM NaCl, 35 mM MgSO4, and 5 mM CaCl2. Pellicle formation, another measure of biofilm development, was also enhanced in these growth conditions. Therefore, both nutrient and salt availability contribute to V. fischeri biofilm formation. While growth was unaffected, these optimized conditions resulted in increased syp locus expression as measured by a PsypA-lacZ transcriptional reporter. We anticipate these studies will help us understand how the natural environment of V. fischeri affects its ability to form biofilms and, ultimately, colonize E. scolopes.

Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens

NASA Astrophysics Data System (ADS)

Gharajehdaghipour, Tazarve; Roth, James D.; Fafard, Paul M.; Markham, John H.

2016-04-01

Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ15N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra.

Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens.

PubMed

Gharajehdaghipour, Tazarve; Roth, James D; Fafard, Paul M; Markham, John H

2016-04-05

Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ(15)N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra.

Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens

PubMed Central

Gharajehdaghipour, Tazarve; Roth, James D.; Fafard, Paul M.; Markham, John H.

2016-01-01

Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ15N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra. PMID:27045973

Drainage and fertilization effects on nutrient availability in an ombrotrophic peatland.

PubMed

Wang, Meng; Talbot, Julie; Moore, Tim R

2018-04-15

Nutrient availability is an important control on the vegetation distribution, productivity and functioning of peatland ecosystems and we examined spatial and temporal patterns of nutrient availability through ion exchange at Mer Bleue bog, southeast Ontario, Canada. We installed ion exchange probes at 5-15cm for 4weeks and determined nutrient sorption at undisturbed sites as well as those affected by nitrogen (N), phosphorus (P), potassium (K) fertilization and drainage. Under undisturbed conditions, the bog had very small amount of available nutrients, especially N (ammonium>nitrate) and P, and exhibited small variations in nutrient availability during the growing season (May to October). The increase in NPK availability upon fertilization was short-lived over the season and the stoichiometry of available NPK captured by the probes was mismatched with the vegetation. The increase in nutrient availability with drainage was confounded by substantial changes in vegetation. We compare these results with data from other Canadian bogs and fens to provide baseline data on nutrient availability in peatlands. Copyright © 2017 Elsevier B.V. All rights reserved.

A review of the use of engineered nanomaterials to suppress plant disease and enhance crop yield

NASA Astrophysics Data System (ADS)

Servin, Alia; Elmer, Wade; Mukherjee, Arnab; De la Torre-Roche, Roberto; Hamdi, Helmi; White, Jason C.; Bindraban, Prem; Dimkpa, Christian

2015-02-01

Nanotechnology has the potential to play a critical role in global food production, food security, and food safety. The applications of nanotechnology in agriculture include fertilizers to increase plant growth and yield, pesticides for pest and disease management, and sensors for monitoring soil quality and plant health. Over the past decade, a number of patents and products incorporating nanomaterials into agricultural practices (e.g., nanopesticides, nanofertilizers, and nanosensors) have been developed. The collective goal of all of these approaches is to enhance the efficiency and sustainability of agricultural practices by requiring less input and generating less waste than conventional products and approaches. This review evaluates the current literature on the use of nanoscale nutrients (metals, metal oxides, carbon) to suppress crop disease and subsequently enhance growth and yield. Notably, this enhanced yield may not only be directly linked to the reduced presence of pathogenic organisms, but also to the potential nutritional value of the nanoparticles themselves, especially for the essential micronutrients necessary for host defense. We also posit that these positive effects are likely a result of the greater availability of the nutrients in the "nano" form. Last, we offer comments on the current regulatory perspective for such applications.

Long-term Nutrient Fertilization Increases CO2 Loss in Arctic Tundra

NASA Astrophysics Data System (ADS)

Graham, L. M.; Natali, S.; Rastetter, E. B.; Shaver, G. R.; Risk, D. A.; Loranty, M. M.; Jastrow, J. D.

2015-12-01

As anthropogenic climate change warms the Arctic, organic carbon (C) trapped in permafrost is at an increased risk of being released to the atmosphere as carbon dioxide (CO2). At the same time, higher rates of decomposition may increase nutrient availability and enhance plant growth, leading to an uptake of C that may offset respiratory losses. Arctic tundra ecosystems are highly nitrogen (N) limited, and the indirect effects of warming on nutrient availability will be the most likely outcome of increased temperature on plant productivity. This study aims to understand the effects of nutrient addition on arctic CO2 and H2O exchange in a tundra ecosystem at Toolik Lake Field Station, Alaska. The nutrient addition experiment, which began in 2006, is comprised of 7 fertilization treatments: 0.5, 1, 2, 5, and 10 g m-2 of N as NO3- and NH4+ (1:1) with 0.25, 0.5, 1, 2.5, and 5 g m-2 of phosphorus as PO43-; 5 g m-2 of N as NO3-; 5 g m-2 of N as NH4+, and one control plot. Plot-level CO2 and H2O exchange was measured at 5 light levels 7 times over a four-week period in June and July 2015. We measured ecosystem CO2 and H2O exchange using a rectangular plexiglass chamber (0.49 m2) that was connected to an infrared gas analyzer (LI-840). Other ecosystem variables measured include thaw depth, soil moisture and temperature, and normalized difference vegetation index. After 10 years of nutrient addition, fertilization significantly altered ecosystem C cycling. Soil respiration was greatest in the highest fertilization treatment (2.97 μmol m-2 s-1), increasing linearly with nutrient level at a rate of 0.133 μmol m-2 s-1 per g m-2 of N added (R2=0.914). Net CO2 uptake was greatest under highest fertilization (-2.06 μmol m-2 s-1), decreasing linearly with nutrient addition at a rate of -0.068 μmol m-2 s-1 per g m-2 of N added (R2=0.687). These results suggest that as nutrients become more available under a warmer climate, plant productivity increases may not offset respiratory losses, leading to a positive feedback to global climate.

The relative importance of vertical soil nutrient heterogeneity, and mean and depth-specific soil nutrient availabilities for tree species richness in tropical forests and woodlands.

PubMed

Shirima, Deo D; Totland, Ørjan; Moe, Stein R

2016-11-01

The relative importance of resource heterogeneity and quantity on plant diversity is an ongoing debate among ecologists, but we have limited knowledge on relationships between tree diversity and heterogeneity in soil nutrient availability in tropical forests. We expected tree species richness to be: (1) positively related to vertical soil nutrient heterogeneity; (2) negatively related to mean soil nutrient availability; and (3) more influenced by nutrient availability in the upper than lower soil horizons. Using a data set from 60, 20 × 40-m plots in a moist forest, and 126 plots in miombo woodlands in Tanzania, we regressed tree species richness against vertical soil nutrient heterogeneity, both depth-specific (0-15, 15-30, and 30-60 cm) and mean soil nutrient availability, and soil physical properties, with elevation and measures of anthropogenic disturbance as co-variables. Overall, vertical soil nutrient heterogeneity was the best predictor of tree species richness in miombo but, contrary to our prediction, the relationships between tree species richness and soil nutrient heterogeneity were negative. In the moist forest, mean soil nutrient availability explained considerable variations in tree species richness, and in line with our expectations, these relationships were mainly negative. Soil nutrient availability in the top soil layer explained more of the variation in tree species richness than that in the middle and lower layers in both vegetation types. Our study shows that vertical soil nutrient heterogeneity and mean availability can influence tree species richness at different magnitudes in intensively utilized tropical vegetation types.

Nutrients Can Enhance the Abundance and Expression of Alkane Hydroxylase CYP153 Gene in the Rhizosphere of Ryegrass Planted in Hydrocarbon-Polluted Soil

PubMed Central

Arslan, Muhammad; Afzal, Muhammad; Amin, Imran; Iqbal, Samina; Khan, Qaiser M.

2014-01-01

Plant-bacteria partnership is a promising strategy for the remediation of soil and water polluted with hydrocarbons. However, the limitation of major nutrients (N, P and K) in soil affects the survival and metabolic activity of plant associated bacteria. The objective of this study was to explore the effects of nutrients on survival and metabolic activity of an alkane degrading rhizo-bacterium. Annual ryegrass (Lolium multiflorum) was grown in diesel-contaminated soil and inoculated with an alkane degrading bacterium, Pantoea sp. strain BTRH79, in greenhouse experiments. Two levels of nutrients were applied and plant growth, hydrocarbon removal, and gene abundance and expression were determined after 100 days of sowing of ryegrass. Results obtained from these experiments showed that the bacterial inoculation improved plant growth and hydrocarbon degradation and these were further enhanced by nutrients application. Maximum plant biomass production and hydrocarbon mineralization was observed by the combined use of inoculum and higher level of nutrients. The presence of nutrients in soil enhanced the colonization and metabolic activity of the inoculated bacterium in the rhizosphere. The abundance and expression of CYP153 gene in the rhizosphere of ryegrass was found to be directly associated with the level of applied nutrients. Enhanced hydrocarbon degradation was associated with the population of the inoculum bacterium, the abundance and expression of CYP153 gene in the rhizosphere of ryegrass. It is thus concluded that the combination between vegetation, inoculation with pollutant-degrading bacteria and nutrients amendment was an efficient approach to reduce hydrocarbon contamination. PMID:25360680

Functional traits determine tree growth and ecosystem productivity of a tropical montane forest: Insights from a long-term nutrient manipulation experiment.

PubMed

Báez, Selene; Homeier, Jürgen

2018-01-01

Trait-response effects are critical to forecast community structure and biomass production in highly diverse tropical forests. Ecological theory and few observation studies indicate that trees with acquisitive functional traits would respond more strongly to higher resource availability than those with conservative traits. We assessed how long-term tree growth in experimental nutrient addition plots (N, P, and N + P) varied as a function of morphological traits, tree size, and species identity. We also evaluated how trait-based responses affected stand scale biomass production considering the community structure. We found that tree growth depended on interactions between functional traits and the type or combination of nutrients added. Common species with acquisitive functional traits responded more strongly to nutrient addition, mainly to N + P. Phosphorous enhanced the growth rates of species with acquisitive and conservative traits, had mostly positive effects on common species and neutral or negative effects in rare species. Moreover, trees receiving N + P grew faster irrespective of their initial size relative to trees in control or to trees in other treatment plots. Finally, species responses were highly idiosyncratic suggesting that community processes including competition and niche dimensionality may be altered under increased resource availability. We found no statistically significant effects of nutrient additions on aboveground biomass productivity because acquisitive species had a limited potential to increase their biomass, possibly due to their generally lower wood density. In contrast, P addition increased the growth rates of species characterized by more conservative resource strategies (with higher wood density) that were poorly represented in the plant community. We provide the first long-term experimental evidence that trait-based responses, community structure, and community processes modulate the effects of increased nutrient availability on biomass productivity in a tropical forest. © 2017 John Wiley & Sons Ltd.

Nutrition of mangroves.

PubMed

Reef, Ruth; Feller, Ilka C; Lovelock, Catherine E

2010-09-01

Mangrove forests dominate the world's tropical and subtropical coastlines. Similar to other plant communities, nutrient availability is one of the major factors influencing mangrove forest structure and productivity. Many mangrove soils have extremely low nutrient availability, although nutrient availability can vary greatly among and within mangrove forests. Nutrient-conserving processes in mangroves are well developed and include evergreeness, resorption of nutrients prior to leaf fall, the immobilization of nutrients in leaf litter during decomposition, high root/shoot ratios and the repeated use of old root channels. Both nitrogen-use efficiency and nutrient resorption efficiencies in mangroves are amongst the highest recorded for angiosperms. A complex range of interacting abiotic and biotic factors controls the availability of nutrients to mangrove trees, and mangroves are characteristically plastic in their ability to opportunistically utilize nutrients when these become available. Nitrogen and phosphorus have been implicated as the nutrients most likely to limit growth in mangroves. Ammonium is the primary form of nitrogen in mangrove soils, in part as a result of anoxic soil conditions, and tree growth is supported mainly by ammonium uptake. Nutrient enrichment is a major threat to marine ecosystems. Although mangroves have been proposed to protect the marine environment from land-derived nutrient pollution, nutrient enrichment can have negative consequences for mangrove forests and their capacity for retention of nutrients may be limited.

Simulated global change: contrasting short and medium term growth and reproductive responses of a common alpine/Arctic cushion plant to experimental warming and nutrient enhancement.

PubMed

Alatalo, Juha M; Little, Chelsea J

2014-01-01

Cushion plants are important components of alpine and Arctic plant communities around the world. They fulfill important roles as facilitators, nurse plants and foundation species across trophic levels for vascular plants, arthropods and soil microorganisms, the importance of these functions increasing with the relative severity of the environment. Here we report results from one of the few experimental studies simulating global change impacts on cushion plants; a factorial experiment with warming and nutrient enhancement that was applied to an alpine population of the common nurse plant, Silene acaulis, in sub-arctic Sweden. Experimental perturbations had significant short-term impacts on both stem elongation and leaf length. S. acaulis responded quickly by increasing stem elongation and (to a lesser extent) leaf length in the warming, nutrient, and the combined warming and nutrient enhancements. Cover and biomass also initially increased in response to the perturbations. However, after the initial positive short-term responses, S. acaulis cover declined in the manipulations, with the nutrient and combined warming and nutrient treatments having largest negative impact. No clear patterns were found for fruit production. Our results show that S. acaulis living in harsh environments has potential to react quickly when experiencing years with favorable conditions, and is more responsive to nutrient enhancement than to warming in terms of vegetative growth. While these conditions have an initial positive impact, populations experiencing longer-term increased nutrient levels will likely be negatively affected.

Long- and short-term changes in nutrient availability following commercial sawlog harvest via cable logging

Treesearch

Jennifer Knoepp; Wayne Swank; Bruce L. Haines

2014-01-01

Soil nutrient availability often limits forest productivity and soils have considerable variation in their ability to supply nutrients. Most southern Appalachian forests are minimally managed with no fertilizer inputs or routine thinning regime. Nutrient availability is regulated by atmospheric inputs and the internal cycling of nutrients through such processes as...

Leaf nitrogen and phosphorus of temperate desert plants in response to climate and soil nutrient availability

PubMed Central

He, Mingzhu; Dijkstra, Feike A.; Zhang, Ke; Li, Xinrong; Tan, Huijuan; Gao, Yanhong; Li, Gang

2014-01-01

In desert ecosystems, plant growth and nutrient uptake are restricted by availability of soil nitrogen (N) and phosphorus (P). The effects of both climate and soil nutrient conditions on N and P concentrations among desert plant life forms (annual, perennial and shrub) remain unclear. We assessed leaf N and P levels of 54 desert plants and measured the corresponding soil N and P in shallow (0–10 cm), middle (10–40 cm) and deep soil layers (40–100 cm), at 52 sites in a temperate desert of northwest China. Leaf P and N:P ratios varied markedly among life forms. Leaf P was higher in annuals and perennials than in shrubs. Leaf N and P showed a negative relationship with mean annual temperature (MAT) and no relationship with mean annual precipitation (MAP), but a positive relationship with soil P. Leaf P of shrubs was positively related to soil P in the deep soil. Our study indicated that leaf N and P across the three life forms were influenced by soil P. Deep-rooted plants may enhance the availability of P in the surface soil facilitating growth of shallow-rooted life forms in this N and P limited system, but further research is warranted on this aspect. PMID:25373739

Leaf nitrogen and phosphorus of temperate desert plants in response to climate and soil nutrient availability

NASA Astrophysics Data System (ADS)

He, Mingzhu; Dijkstra, Feike A.; Zhang, Ke; Li, Xinrong; Tan, Huijuan; Gao, Yanhong; Li, Gang

2014-11-01

In desert ecosystems, plant growth and nutrient uptake are restricted by availability of soil nitrogen (N) and phosphorus (P). The effects of both climate and soil nutrient conditions on N and P concentrations among desert plant life forms (annual, perennial and shrub) remain unclear. We assessed leaf N and P levels of 54 desert plants and measured the corresponding soil N and P in shallow (0-10 cm), middle (10-40 cm) and deep soil layers (40-100 cm), at 52 sites in a temperate desert of northwest China. Leaf P and N:P ratios varied markedly among life forms. Leaf P was higher in annuals and perennials than in shrubs. Leaf N and P showed a negative relationship with mean annual temperature (MAT) and no relationship with mean annual precipitation (MAP), but a positive relationship with soil P. Leaf P of shrubs was positively related to soil P in the deep soil. Our study indicated that leaf N and P across the three life forms were influenced by soil P. Deep-rooted plants may enhance the availability of P in the surface soil facilitating growth of shallow-rooted life forms in this N and P limited system, but further research is warranted on this aspect.

Organic wastes from bioenergy and ecological sanitation as a soil fertility improver: a field experiment in a tropical Andosol

NASA Astrophysics Data System (ADS)

Krause, Ariane; Nehls, Thomas; George, Eckhard; Kaupenjohann, Martin

2016-04-01

Andosols require the regular application of phosphorus (P) to sustain crop productivity. On an Andosol in NW Tanzania, we studied the short-term effects of amending standard compost, biogas slurry and CaSa compost (containing biochar and sanitized human excreta) on (i) the soil's physico-chemical properties, on (ii) biomass growth and crop productivity, and on (iii) the plants' nutrient status. The practice-oriented experiment design included the intercropping of seven locally grown crop species planted on 9 m2 plots with five repetitions arranged as a Latin rectangle. Differences in plant growth (biomass production and crop yield, e.g., of Zea mays) and crop nutrition (total C, N, P, K, Ca, Mg, Zn, etc.) were related to pH, CEC (cation exchange capacity), total C and the availability of nutrients (N, P, K, etc.) and water (water retention characteristics, bulk density, etc.) in the soil. None of the amendments had any significant effect on soil water availability, so the observed variations in crop yield and plant nutrition are attributed to nutrient availability. Applying CaSa compost increased the soil pH from 5.3 to 5.9 and the level of available P from 0.5 to 4.4 mg per kg. Compared to the control, adding biogas slurry, standard compost and CaSa compost increased the aboveground biomass of Zea mays by, respectively, 140, 154 and 211 %. The grain yields of maize on soil treated with biogas slurry, standard compost and CaSa compost were, respectively, 2.63, 3.18 and 4.40 t ha-1, compared to only 1.10 t ha-1 on unamended plots. All treatments enhanced crop productivity and increased the uptake of nutrients into the maize grains. The CaSa compost was most effective in mitigating P deficiency and soil acidification. We conclude that all treatments are viable as a substitute for synthetic fertilizers. Nevertheless, further steps are required to integrate the tested soil amendments into farm-scale nutrient management and to balance the additions and removals of nutrients, so that the cycle can be closed.

The use of vermicompost in organic farming: overview, effects on soil and economics.

PubMed

Lim, Su Lin; Wu, Ta Yeong; Lim, Pei Nie; Shak, Katrina Pui Yee

2015-04-01

Vermicomposting is a process in which earthworms are used to convert organic materials into humus-like material known as vermicompost. A number of researchers throughout the world have found that the nutrient profile in vermicompost is generally higher than traditional compost. In fact, vermicompost can enhance soil fertility physically, chemically and biologically. Physically, vermicompost-treated soil has better aeration, porosity, bulk density and water retention. Chemical properties such as pH, electrical conductivity and organic matter content are also improved for better crop yield. Nevertheless, enhanced plant growth could not be satisfactorily explained by improvements in the nutrient content of the soil, which means that other plant growth-influencing materials are available in vermicomposts. Although vermicomposts have been shown to improve plant growth significantly, the application of vermicomposts at high concentrations could impede growth due to the high concentrations of soluble salts available in vermicomposts. Therefore, vermicomposts should be applied at moderate concentrations in order to obtain maximum plant yield. This review paper discusses in detail the effects of vermicompost on soil fertility physically, chemically and biologically. Future prospects and economy on the use of organic fertilizers in the agricultural sector are also examined. © 2014 Society of Chemical Industry.

Subsurface application enhances benefits of manure redistribution

USDA-ARS?s Scientific Manuscript database

Sustainable nutrient management requires redistribution of livestock manure from nutrient-excess areas to nutrient-deficit areas. Field experiments were conducted to assess agronomic (i.e., corn yield) and environmental (i.e., ammonia volatilization and surface nutrient losses) effects of different ...

A specific multi-nutrient formulation enhances M1 muscarinic acetylcholine receptor responses in vitro.

PubMed

Savelkoul, Paul J M; Janickova, Helena; Kuipers, Almar A M; Hageman, Robert J J; Kamphuis, Patrick J; Dolezal, Vladimir; Broersen, Laus M

2012-02-01

Recent evidence indicates that supplementation with a specific combination of nutrients may affect cell membrane synthesis and composition. To investigate whether such nutrients may also modify the physical properties of membranes, and affect membrane-bound processes involved in signal transduction pathways, we studied the effects of nutrient supplementation on G protein-coupled receptor activation in vitro. In particular, we investigated muscarinic receptors, which are important for the progression of memory deterioration and pathology of Alzheimer's disease. Nerve growth factor differentiated pheochromocytoma cells that were supplemented with specific combinations of nutrients showed enhanced responses to muscarinic receptor agonists in a membrane potential assay. The largest effects were obtained with a combination of nutrients known as Fortasyn™ Connect, comprising docosahexaenoic acid, eicosapentaenoic acid, uridine monophosphate as a uridine source, choline, vitamin B6, vitamin B12, folic acid, phospholipids, vitamin C, vitamin E, and selenium. In subsequent experiments, it was shown that the effects of supplementation could not be attributed to single nutrients. In addition, it was shown that the agonist-induced response and the supplement-induced enhancement of the response were blocked with the muscarinic receptor antagonists atropine, telenzepine, and AF-DX 384. In order to determine whether the effects of Fortasyn™ Connect supplementation were receptor subtype specific, we investigated binding properties and activation of human muscarinic M1, M2 and M4 receptors in stably transfected Chinese hamster ovary cells after supplementation. Multi-nutrient supplementation did not change M1 receptor density in plasma membranes. However, M1 receptor-mediated G protein activation was significantly enhanced. In contrast, supplementation of M2- or M4-expressing cells did not affect receptor signaling. Taken together, these results indicate that a specific combination of nutrients acts synergistically in enhancing muscarinic M1 receptor responses, probably by facilitating receptor-mediated G protein activation. © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.

Effects of nutrient optimization on intra-annual wood formation in Norway spruce.

PubMed

Kalliokoski, Tuomo; Mäkinen, Harri; Jyske, Tuula; Nöjd, Pekka; Linder, Sune

2013-11-01

In the Nordic countries, growth of Norway spruce (Picea abies (L.) Karst.) is generally limited by low availability of nutrients, especially nitrogen. Optimizing forest management requires better insight on how growth responds to the environmental conditions and their manipulation. The aim of this study was to analyse the effects of nutrient optimization on timing and the rate of tracheid formation of Norway spruce and to follow the differentiation of newly formed tracheids. The study was performed during two growing seasons in a long-term nutrient optimization experiment in northern Sweden, where all essential macro- and micronutrients were supplied in irrigation water every second day from mid-June to mid-August. The control plots were without additional nutrients and water. Tracheid formation in the stem was monitored throughout the growing season by weekly sampling of microcores at breast height. The onset of xylogenesis occurred in early June, but in early summer there were no significant between-treatment differences in the onset and relative rate of tracheid formation. In both treatments, the onset of secondary cell wall formation occurred in mid-June. The maximum rate of tracheid formation occurred close to the summer solstice and 50% of the tracheids had been accumulated in early July. Optimized nutrition resulted in the formation of ∼50% more tracheids and delayed the cessation of tracheid formation, which extended the tracheid formation period by 20-50%, compared with control trees. The increased growth was mainly an effect of enhanced tracheid formation rate during the mid- and later-part of the growing season. In the second year, the increased growth rate also resulted in 11% wider tracheids. We conclude that the onset and rate of tracheid formation and differentiation during summer is primarily controlled by photoperiod, temperature and availability of nutrients, rather than supply of carbohydrates.

Mapping nutrient resorption efficiencies of subarctic cryptogams and seed plants onto the Tree of Life

PubMed Central

Lang, Simone I; Aerts, Rien; van Logtestijn, Richard S P; Schweikert, Wenka; Klahn, Thorsten; Quested, Helen M; van Hal, Jurgen R; Cornelissen, Johannes H C

2014-01-01

Nutrient resorption from senescing photosynthetic organs is a powerful mechanism for conserving nitrogen (N) and phosphorus (P) in infertile environments. Evolution has resulted in enhanced differentiation of conducting tissues to facilitate transport of photosynthate to other plant parts, ultimately leading to phloem. Such tissues may also serve to translocate N and P to other plant parts upon their senescence. Therefore, we hypothesize that nutrient resorption efficiency (RE, % of nutrient pool exported) should correspond with the degree of specialization of these conducting tissues across the autotrophic branches of the Tree of Life. To test this hypothesis, we had to compare members of different plant clades and lichens within a climatic region, to minimize confounding effects of climatic drivers on nutrient resorption. Thus, we compared RE among wide-ranging basal clades from the principally N-limited subarctic region, employing a novel method to correct for mass loss during senescence. Even with the limited numbers of species available for certain clades in this region, we found some consistent patterns. Mosses, lichens, and lycophytes generally showed low REN (<20%), liverworts and conifers intermediate (40%) and monilophytes, eudicots, and monocots high (>70%). REP appeared higher in eudicots and liverworts than in mosses. Within mosses, taxa with more efficient conductance also showed higher REN. The differences in REN among clades broadly matched the degree of specialization of conducting tissues. This novel mapping of a physiological process onto the Tree of Life broadly supports the idea that the evolution of conducting tissues toward specialized phloem has aided land plants to optimize their internal nitrogen recycling. The generality of evolutionary lines in conducting tissues and nutrient resorption efficiency needs to be tested across different floras in different climatic regions with different levels of N versus P availability. PMID:25360262

Long term growth responses of loblolly pine to optimal nutrient and water resource availability

Treesearch

Timothy J. Albaugh; H. Lee Allen; Phillip M. Dougherty; Kurt H. Johnsen

2004-01-01

A factorial combination of four treatments (control (CW), optimal growing season water availability (IW), optimum nutrient availability (FW), and combined optimum water and nutrient availability (FIW)) in four replications were initiated in an 8-year- old Pinus taeda stand growing on a droughty, nutrient-poor, sandy site in Scotland County, NC and...

Development of a diverse epiphyte community in response to phosphorus fertilization.

PubMed

Benner, Jon W; Vitousek, Peter M

2007-07-01

The role of terrestrial soil nutrient supply in determining the composition and productivity of epiphyte communities has been little investigated. In a montane Hawaiian rainforest, we documented dramatic increases in the abundance and species richness of canopy epiphytes in a forest that had been fertilized annually with phosphorus (P) for 15 years; there was no response in forest that had been fertilized with nitrogen (N) or other nutrients. The response of N-fixing lichens to P fertilization was particularly strong, although mosses and non-N-fixing lichens also increased in abundance and diversity. We show that enhancement of canopy P availability is the most likely factor driving the bloom in epiphytes. These results provide strong evidence that terrestrial soil fertility may structure epiphyte communities, and in particular that the abundance of N-fixing lichens--a functionally important epiphyte group--may be particularly sensitive to ecosystem P availability.

Peatland simulator connecting drainage, nutrient cycling, forest growth, economy and GHG efflux in boreal and tropical peatlands

NASA Astrophysics Data System (ADS)

Lauren, Ari; Hökkä, Hannu; Launiainen, Samuli; Palviainen, Marjo; Lehtonen, Aleksi

2016-04-01

Forest growth in peatlands is nutrient limited; principal source of nutrients is the decomposition of organic matter. Excess water decreases O2 diffusion and slows down the nutrient release. Drainage increases organic matter decomposition, CO2 efflux, and nutrient supply, and enhances the growth of forest. Profitability depends on costs, gained extra yield and its allocation into timber assortments, and the rate of interest. We built peatland simulator Susi to define and parameterize these interrelations. We applied Susi-simulator to compute water and nutrient processes, forest growth, and CO2 efflux of forested drained peatland. The simulator computes daily water fluxes and storages in two dimensions for a peatland forest strip located between drainage ditches. The CO2 efflux is made proportional to peat bulk density, soil temperature and O2 availability. Nutrient (N, P, K) release depends on decomposition and peat nutrient content. Growth limiting nutrient is detected by comparing the need and supply of nutrients. Increased supply of growth limiting nutrient is used to quantify the forest growth response to improved drainage. The extra yield is allocated into pulpwood and sawlogs based on volume of growing stock. The net present values of ditch cleaning operation and the gained extra yield are computed under different rates of interest to assess the profitability of the ditch cleaning. The hydrological sub-models of Susi-simulator were first parameterized using daily water flux data from Hyytiälä SMEAR II-site, after which the predictions were tested against independent hydrologic data from two drained peatland forests in Southern Finland. After verification of the hydrologic model, the CO2 efflux, nutrient release and forest growth proportionality hypothesis was tested and model performance validated against long-term forest growth and groundwater level data from 69 forested peatland sample plots in Central Finland. The results showed a clear relation between the stand growth, nutrient availability, and CO2 efflux. Potassium was the main limiting factor for the forest growth. This indicates that management aiming at decreasing heterotrophic CO2 efflux by raising the ground water table will decrease the forest growth. From the C balance perspective the growth rate of the tree stand becomes essential. Modelling approach enables a search for an optimal management schedule for producing timber in situation when there is a price given for release of C. Ditch network maintenance by ditch cleaning becomes profitable if: i) the initial drainage is very poor, ii) the availability of the critical nutrient is sufficient, iii) during prolonged rainy conditions, and iv) the tree stand is Scots pine (Pinus sylvestris) dominated and v) in a phase where most of the extra yield is allocated into sawlogs. The simulator and its holistic approach has been successfully implemented in both tropical pulpwood plantations in Sumatra, Indonesia and in Finnish boreal forests.

Dynamic investigation of nutrient consumption and injection strategy in microbial enhanced oil recovery (MEOR) by means of large-scale experiments.

PubMed

Song, Zhiyong; Zhu, Weiyao; Sun, Gangzheng; Blanckaert, Koen

2015-08-01

Microbial enhanced oil recovery (MEOR) depends on the in situ microbial activity to release trapped oil in reservoirs. In practice, undesired consumption is a universal phenomenon but cannot be observed effectively in small-scale physical simulations due to the scale effect. The present paper investigates the dynamics of oil recovery, biomass and nutrient consumption in a series of flooding experiments in a dedicated large-scale sand-pack column. First, control experiments of nutrient transportation with and without microbial consumption were conducted, which characterized the nutrient loss during transportation. Then, a standard microbial flooding experiment was performed recovering additional oil (4.9 % Original Oil in Place, OOIP), during which microbial activity mostly occurred upstream, where oil saturation declined earlier and steeper than downstream in the column. Subsequently, more oil remained downstream due to nutrient shortage. Finally, further research was conducted to enhance the ultimate recovery by optimizing the injection strategy. An extra 3.5 % OOIP was recovered when the nutrients were injected in the middle of the column, and another additional 11.9 % OOIP were recovered by altering the timing of nutrient injection.

Enhancing phosphorus and zinc acquisition efficiency in rice: a critical review of root traits and their potential utility in rice breeding.

PubMed

Rose, T J; Impa, S M; Rose, M T; Pariasca-Tanaka, J; Mori, A; Heuer, S; Johnson-Beebout, S E; Wissuwa, M

2013-07-01

Rice is the world's most important cereal crop and phosphorus (P) and zinc (Zn) deficiency are major constraints to its production. Where fertilizer is applied to overcome these nutritional constraints it comes at substantial cost to farmers and the efficiency of fertilizer use is low. Breeding crops that are efficient at acquiring P and Zn from native soil reserves or fertilizer sources has been advocated as a cost-effective solution, but would benefit from knowledge of genes and mechanisms that confer enhanced uptake of these nutrients by roots. This review discusses root traits that have been linked to P and Zn uptake in rice, including traits that increase mobilization of P/Zn from soils, increase the volume of soil explored by roots or root surface area to recapture solubilized nutrients, enhance the rate of P/Zn uptake across the root membrane, and whole-plant traits that affect root growth and nutrient capture. In particular, this review focuses on the potential for these traits to be exploited through breeding programmes to produce nutrient-efficient crop cultivars. Few root traits have so far been used successfully in plant breeding for enhanced P and Zn uptake in rice or any other crop. Insufficient genotypic variation for traits or the failure to enhance nutrient uptake under realistic field conditions are likely reasons for the limited success. More emphasis is needed on field studies in mapping populations or association panels to identify those traits and underlying genes that are able to enhance nutrient acquisition beyond the level already present in most cultivars.

Nutrient availability at Mer Bleue bog measured by PRSTM probes

NASA Astrophysics Data System (ADS)

Wang, M.; Moore, T. R.; Talbot, J.

2015-12-01

Bogs, covering ~0.7 million km2 in Canada, store a large amount of C and N. As nutrient deficient ecosystems, it's critical to examine the nutrient availabilities and seasonal dynamics. We used Plant Root Simulators (PRSTM) at Mer Bleue bog to provide some baseline data on nutrient availability and its variability. In particular, we focused on ammonium, nitrate, phosphate, calcium, magnesium and potassium, iron, sulphate and aluminum. We placed PRS probes at a depth of 5 - 15 cm in pristine plots and plots with long term N, P and K fertilization for 4 weeks and determined the availability of these nutrients, from spring through to fall. Probes were also placed beneath the water table in hummock and hollow microtopography and along a transect including part of the bog which had been drained through the creation of a ditch 80 years ago. The result showed that there was limited available ammonium, nitrate and phosphate in the bog, the seasonal variation of nutrient availabilities probably due to mineralization, an increase in the availability of some nutrients between different water table depths or as a result of drainage, and the relative availability of nutrients compared to the input from fertilization. We suggest that PRS probes could be a useful tool to examine nutrient availability and dynamics in wetlands, with careful consideration of installing condition, for example, proper exposure period, depth relative to water table etc.

Plant response to nutrient availability across variable bedrock geologies

USGS Publications Warehouse

Castle, S.C.; Neff, J.C.

2009-01-01

We investigated the role of rock-derived mineral nutrient availability on the nutrient dynamics of overlying forest communities (Populus tremuloides and Picea engelmanni-Abies lasiocarpa v. arizonica) across three parent materials (andesite, limestone, and sandstone) in the southern Rocky Mountains of Colorado. Broad geochemical differences were observed between bedrock materials; however, bulk soil chemistries were remarkably similar between the three different sites. In contrast, soil nutrient pools were considerably different, particularly for P, Ca, and Mg concentrations. Despite variations in nutrient stocks and nutrient availability in soils, we observed relatively inflexible foliar concentrations and foliar stoichiometries for both deciduous and coniferous species. Foliar nutrient resorption (P and K) in the deciduous species followed patterns of nutrient content across substrate types, with higher resorption corresponding to lower bedrock concentrations. Work presented here indicates a complex plant response to available soil nutrients, wherein plant nutrient use compensates for variations in supply gradients and results in the maintenance of a narrow range in foliar stoichiometry. ?? 2008 Springer Science+Business Media, LLC.

Enhanced Remediation of Toluene in the Vadose Zone via a Nitrate-Rich Nutrient Solution: Field Study

NASA Astrophysics Data System (ADS)

Tindall, J. A.; Friedel, M. J.

2003-12-01

The objective of this study was to test the effectiveness of nitrate-rich nutrient solutions and hydrogen peroxide (H202) to enhance in-situ microbial remediation of toluene. Three sand filled plots (2 m2 surface area and 1.5 meters deep) were tested in three phases (each phase lasting approximately 2 weeks). During each phase, toluene (21.6 mol as an emulsion in 50L of water) was applied uniformly via sprinkler irrigation. Passive remediation was allowed to occur during the first (control) phase. A nutrient solution (modified Hoagland), concentrated in 40L of water, was tested during the second phase. The final phase involved addition of 230 moles of H202 in 50L of water to increase the available oxygen needed for aerobic biodegradation. During the first phase, toluene concentrations in soil gas were reduced from 120 ppm to 25 ppm in 14 days. After the addition of nutrients during the second phase, concentrations were reduced from 90 ppm to about 8 ppm within 14 days, and for the third phase (H202), toluene concentrations were about 1 ppm after only five days. Initial results suggest that this method could be an effective means of remediating a contaminated site, directly after a BTEX spill, without the intrusiveness and high cost of other abatement technologies such as bioventing and soil vapor extraction. However, further tests need to be completed to determine the effect of each of the BTEX components.

Part 2: A field study of enhanced remediation of Toluene in the vadose zone using a nutrient solution

USGS Publications Warehouse

Tindall, J.A.; Weeks, E.P.; Friedel, M.

2005-01-01

The objective of this study was to test the effectiveness of a nitrate-rich nutrient solution and hydrogen peroxide (H2O2) to enhance in-situ microbial remediation of toluene in the unsaturated zone. Three sand-filled plots were tested in three phases (each phase lasting approximately 2 weeks). During the control phase, toluene was applied uniformly via sprinkler irrigation. Passive remediation was allowed to occur during this phase. A modified Hoagland nutrient solution, concentrated in 150 L of water, was tested during the second phase. The final phase involved addition of 230 moles of H2O2 in 150 L of water to increase the available oxygen needed for aerobic biodegradation. During the first phase, measured toluene concentrations in soil gas were reduced from 120 ppm to 25 ppm in 14 days. After the addition of nutrients during the second phase, concentrations were reduced from 90 ppm to about 8 ppm within 14 days, and for the third phase (H 2O2), toluene concentrations were about 1 ppm after only 5 days. Initial results suggest that this method could be an effective means of remediating a contaminated site, directly after a BTEX spill, without the intrusiveness and high cost of other abatement technologies such as bioventing or soil-vapor extraction. However, further tests need to be completed to determine the effect of each of the BTEX components. ?? Springer 2005.

Assessing weathered Endicott oil biodegradation in brackish water.

PubMed

Personna, Yves Robert; King, Thomas; Boufadel, Michel C; Zhang, Shuangyi; Kustka, Adam

2014-09-15

We evaluated the biodegradability of physically (WAF) and chemically (CEWAF) dispersed oil in brackish water (salinity ∼6.5 g/L), and the influence of nutrient availability (low nutrient-LN: background water vs. high nutrient-HN: addition of 100 mg NO3-N/L and 10mg PO4-P/L to background water) on oil biodegradation rates at 15±0.5 °C for 42 days. No oil removal occurred in WAF compared with CEWAF: 24% in HN and 14% in LN within two weeks. The oil biodegradation concerned mainly alkanes as confirmed by GC/MS analyses. Higher O2 consumption (10.30 mg L(-1) day(-1)) and CO2 production (3.89 mg CL(-1) day(-1)) were measured in HN compared with LN (O2: 2.79 mg L(-1) day(-1), CO2:0.18 mg CL(-1) day(-1)). Estimated biomass of hydrocarbon degraders and heterotrophic bacteria was at least an order of magnitude larger in HN than in LN. Combining dispersants with nutrients could enhance oil biodegradation and help improve oil spill mitigation responses. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mitochondrial Dynamics Mediated by Mitofusin 1 Is Required for POMC Neuron Glucose-Sensing and Insulin Release Control.

PubMed

Ramírez, Sara; Gómez-Valadés, Alicia G; Schneeberger, Marc; Varela, Luis; Haddad-Tóvolli, Roberta; Altirriba, Jordi; Noguera, Eduard; Drougard, Anne; Flores-Martínez, Álvaro; Imbernón, Mónica; Chivite, Iñigo; Pozo, Macarena; Vidal-Itriago, Andrés; Garcia, Ainhoa; Cervantes, Sara; Gasa, Rosa; Nogueiras, Ruben; Gama-Pérez, Pau; Garcia-Roves, Pablo M; Cano, David A; Knauf, Claude; Servitja, Joan-Marc; Horvath, Tamas L; Gomis, Ramon; Zorzano, Antonio; Claret, Marc

2017-06-06

Proopiomelanocortin (POMC) neurons are critical sensors of nutrient availability implicated in energy balance and glucose metabolism control. However, the precise mechanisms underlying nutrient sensing in POMC neurons remain incompletely understood. We show that mitochondrial dynamics mediated by Mitofusin 1 (MFN1) in POMC neurons couple nutrient sensing with systemic glucose metabolism. Mice lacking MFN1 in POMC neurons exhibited defective mitochondrial architecture remodeling and attenuated hypothalamic gene expression programs during the fast-to-fed transition. This loss of mitochondrial flexibility in POMC neurons bidirectionally altered glucose sensing, causing abnormal glucose homeostasis due to defective insulin secretion by pancreatic β cells. Fed mice lacking MFN1 in POMC neurons displayed enhanced hypothalamic mitochondrial oxygen flux and reactive oxygen species generation. Central delivery of antioxidants was able to normalize the phenotype. Collectively, our data posit MFN1-mediated mitochondrial dynamics in POMC neurons as an intrinsic nutrient-sensing mechanism and unveil an unrecognized link between this subset of neurons and insulin release. Copyright © 2017 Elsevier Inc. All rights reserved.

Recent land cover history and nutrient retention in riparian wetlands

USGS Publications Warehouse

Hogan, D.M.; Walbridge, M.R.

2009-01-01

Wetland ecosystems are profoundly affected by altered nutrient and sediment loads received from anthropogenic activity in their surrounding watersheds. Our objective was to compare a gradient of agricultural and urban land cover history during the period from 1949 to 1997, with plant and soil nutrient concentrations in, and sediment deposition to, riparian wetlands in a rapidly urbanizing landscape. We observed that recent agricultural land cover was associated with increases in Nitrogen (N) and Phosphorus (P) concentrations in a native wetland plant species. Conversely, recent urban land cover appeared to alter receiving wetland environmental conditions by increasing the relative availability of P versus N, as reflected in an invasive, but not a native, plant species. In addition, increases in surface soil Fe content suggests recent inputs of terrestrial sediments associated specifically with increasing urban land cover. The observed correlation between urban land cover and riparian wetland plant tissue and surface soil nutrient concentrations and sediment deposition, suggest that urbanization specifically enhances the suitability of riparian wetland habitats for the invasive species Japanese stiltgrass [Microstegium vimenium (Trinius) A. Camus]. ?? 2009 Springer Science+Business Media, LLC.

Isolation and identification of soil fungi isolates from forest soil for flooded soil recovery

NASA Astrophysics Data System (ADS)

Hazwani Aziz, Nor; Zainol, Norazwina

2018-04-01

Soil fungi have been evaluated for their ability in increasing and recovering nitrogen, phosphorus and potassium content in flooded soil and in promoting the growth of the host plant. Host plant was cultivated in a mixture of fertile forest soil (nutrient-rich soil) and simulated flooded soil (nutrient-poor soil) in an optimized soil condition for two weeks. The soil sample was harvested every day until two weeks of planting and was tested for nitrogen, phosphorus and potassium concentration. Soil fungi were isolated by using dilution plating technique and was identified by Biolog’s Microbial Systems. The concentration of nitrogen, phosphorus, and potassium was found to be increasing after two weeks by two to three times approximately from the initial concentration recorded. Two fungi species were identified with probability more than 90% namely Aspergillus aculeatus and Paecilomyces lilacinus. Both identified fungi were found to be beneficial in enhancing plant growth and increasing the availability of nutrient content in the soil and thus recovering the nutrient content in the flooded soil.

Sagebrush carrying out hydraulic lift enhances surface soil nitrogen cycling and nitrogen uptake into inflorescences.

PubMed

Cardon, Zoe G; Stark, John M; Herron, Patrick M; Rasmussen, Jed A

2013-11-19

Plant roots serve as conduits for water flow not only from soil to leaves but also from wetter to drier soil. This hydraulic redistribution through root systems occurs in soils worldwide and can enhance stomatal opening, transpiration, and plant carbon gain. For decades, upward hydraulic lift (HL) of deep water through roots into dry, litter-rich, surface soil also has been hypothesized to enhance nutrient availability to plants by stimulating microbially controlled nutrient cycling. This link has not been demonstrated in the field. Working in sagebrush-steppe, where water and nitrogen limit plant growth and reproduction and where HL occurs naturally during summer drought, we slightly augmented deep soil water availability to 14 HL+ treatment plants throughout the summer growing season. The HL+ sagebrush lifted greater amounts of water than control plants and had slightly less negative predawn and midday leaf water potentials. Soil respiration was also augmented under HL+ plants. At summer's end, application of a gas-based (15)N isotopic labeling technique revealed increased rates of nitrogen cycling in surface soil layers around HL+ plants and increased uptake of nitrogen into HL+ plants' inflorescences as sagebrush set seed. These treatment effects persisted even though unexpected monsoon rainstorms arrived during assays and increased surface soil moisture around all plants. Simulation models from ecosystem to global scales have just begun to include effects of hydraulic redistribution on water and surface energy fluxes. Results from this field study indicate that plants carrying out HL can also substantially enhance decomposition and nitrogen cycling in surface soils.

Maintaining adequate nutrient supply - Principles, decision-support tools, and best management practices [Chapter 6

Treesearch

Robert B. Harrison; Douglas A. Maguire; Deborah Page-Dumroese

2011-01-01

Maintaining adequate nutrient supply to maintain or enhance tree vigor and forest growth requires conservation of topsoil and soil organic matter. Sometimes nutrient amendments are also required to supplement inherent nutrient-pool limitations or replenish nutrients removed in harvested material. The goal is to maintain the productive potential of the soil and, when...

Effects of agricultural subsidies of nutrients and detritus on fish and plankton of shallow-reservoir ecosystems.

PubMed

Pilati, Alberto; Vanni, Michael J; González, María J; Gaulke, Alicia K

2009-06-01

Agricultural activities increase exports of nutrients and sediments to lakes, with multiple potential impacts on recipient ecosystems. Nutrient inputs enhance phytoplankton and upper trophic levels, and sediment inputs can shade phytoplankton, interfere with feeding of consumers, and degrade benthic habitats. Allochthonous sediments are also a potential food source for detritivores, as is sedimenting autochthonous phytodetritus, the production of which is stimulated by nutrient inputs. We examined effects of allochthonous nutrient and sediment subsidies on fish and plankton, with special emphasis on gizzard shad (Dorosoma cepedianum). This widespread and abundant omnivorous fish has many impacts on reservoir ecosystems, including negative effects on water quality via nutrient cycling and on fisheries via competition with sportfish. Gizzard shad are most abundant in agriculturally impacted, eutrophic systems; thus, agricultural subsidies may affect reservoir food webs directly and by enhancing gizzard shad biomass. We simulated agricultural subsidies of nutrients and sediment detritus by manipulating dissolved nutrients and allochthonous detritus in a 2 x 2 factorial design in experimental ponds. Addition of nutrients alone increased primary production and biomass of zooplanktivorous fish (bluegill and young-of-year gizzard shad). Addition of allochthonous sediments alone increased algal sedimentation and decreased seston and sediment C:P ratios. Ponds receiving both nutrients and sediments showed highest levels of phytoplankton and total phosphorus. Adult and juvenile gizzard shad biomass was enhanced equally by nutrient or sediment addition, probably because this apparently P-limited detritivore ingested similar amounts of P in all subsidy treatments. Nutrient excretion rates of gizzard shad were higher in ponds with nutrient additions, where sediments were composed mainly of phytodetritus. Therefore, gizzard shad can magnify the direct effects of nutrient subsidies on phytoplankton production, and these multiple effects must be considered in strategies to manage eutrophication and fisheries in warmwater reservoir lakes where gizzard shad can dominate fish biomass.

Fine root respiration in the mangrove Rhizophora mangle over variation in forest stature and nutrient availability.

PubMed

Lovelock, Catherine E; Ruess, Roger W; Feller, Ilka C

2006-12-01

Root respiration uses a significant proportion of photosynthetically fixed carbon (C) and is a globally important source of C liberated from soils. Mangroves, which are an important and productive forest resource in many tropical and subtropical countries, sustain a high ratio of root to shoot biomass which may indicate that root respiration is a particularly important component in mangrove forest carbon budgets. Mangroves are often exposed to nutrient pollution from coastal waters. Here we assessed the magnitude of fine root respiration in mangrove forests in Belize and investigated how root respiration is influenced by nutrient additions. Respiration rates of excised fine roots of the mangrove, Rhizophora mangle L., were low (4.01 +/- 0.16 nmol CO(2) g(-1) s(-1)) compared to those measured in temperate tree species at similar temperatures. In an experiment where trees where fertilized with nitrogen (N) or phosphorus (P) in low productivity dwarf forests (1-2 m height) and more productive, taller (4- 7 m height) seaward fringing forests, respiration of fine roots did not vary consistently with fertilization treatments or with forest stature. Fine roots of taller fringe trees had higher concentrations of both N and P compared to dwarf trees. Fertilization with P enhanced fine root P concentrations in both dwarf and fringe trees, but reduced root N concentrations compared to controls. Fertilization with N had no effect on root N or P concentrations. Unlike photosynthetic C gain and growth, which is strongly limited by P availability in dwarf forests at this site, fine root respiration (expressed on a mass basis) was variable, but showed no significant enhancements with nutrient additions. Variation in fine root production and standing biomass are, therefore, likely to be more important factors determining C efflux from mangrove sediments than variations in fine root respiration per unit mass.

Enhanced subarctic Pacific stratification and nutrient utilization during glacials over the last 1.2 Myr

NASA Astrophysics Data System (ADS)

Knudson, Karla P.; Ravelo, Ana Christina

2015-11-01

The relationship between climate, biological productivity, and nutrient flux is of considerable interest in the subarctic Pacific, which represents an important high-nitrate, low-chlorophyll region. While previous studies suggest that changes in iron supply and/or physical ocean stratification could hypothetically explain orbital-scale fluctuations in subarctic Pacific nutrient utilization and productivity, previous records of nutrient utilization are too short to evaluate these relationships over many glacial-interglacial cycles. We present new, high-resolution records of sedimentary δ15N, which offer the first opportunity to evaluate systematic, orbital-scale variations in subarctic Pacific nitrate utilization from 1.2 Ma. Nitrate utilization was enhanced during all glacials, varied with orbital-scale periodicity since the mid-Pleistocene transition, was strongly correlated with enhanced aeolian dust and low atmospheric CO2, but was not correlated with productivity. These results suggest that glacial stratification, rather than iron fertilization, systematically exerted an important regional control on nutrient utilization and air-sea carbon flux.

Enhancing phosphorus and zinc acquisition efficiency in rice: a critical review of root traits and their potential utility in rice breeding

PubMed Central

Rose, T. J.; Impa, S. M.; Rose, M. T.; Pariasca-Tanaka, J.; Mori, A.; Heuer, S.; Johnson-Beebout, S. E.; Wissuwa, M.

2013-01-01

Background Rice is the world's most important cereal crop and phosphorus (P) and zinc (Zn) deficiency are major constraints to its production. Where fertilizer is applied to overcome these nutritional constraints it comes at substantial cost to farmers and the efficiency of fertilizer use is low. Breeding crops that are efficient at acquiring P and Zn from native soil reserves or fertilizer sources has been advocated as a cost-effective solution, but would benefit from knowledge of genes and mechanisms that confer enhanced uptake of these nutrients by roots. Scope This review discusses root traits that have been linked to P and Zn uptake in rice, including traits that increase mobilization of P/Zn from soils, increase the volume of soil explored by roots or root surface area to recapture solubilized nutrients, enhance the rate of P/Zn uptake across the root membrane, and whole-plant traits that affect root growth and nutrient capture. In particular, this review focuses on the potential for these traits to be exploited through breeding programmes to produce nutrient-efficient crop cultivars. Conclusions Few root traits have so far been used successfully in plant breeding for enhanced P and Zn uptake in rice or any other crop. Insufficient genotypic variation for traits or the failure to enhance nutrient uptake under realistic field conditions are likely reasons for the limited success. More emphasis is needed on field studies in mapping populations or association panels to identify those traits and underlying genes that are able to enhance nutrient acquisition beyond the level already present in most cultivars. PMID:23071218

Immobilization and mineralization of N and P by heterotrophic microbes during leaf decomposition

Treesearch

Beth Cheever; Erika Kratzer; Jackson Webster

2012-01-01

According to theory, the rate and stoichiometry of microbial mineralization depend, in part, on nutrient availability. For microbes associated with leaves in streams, nutrients are available from both the water column and the leaf. Therefore, microbial nutrient cycling may change with nutrient availability and during leaf decomposition. We explored spatial and temporal...

Nutrient depletion from rhizosphere solution by maize grown in soil with long-term compost amendment

USDA-ARS?s Scientific Manuscript database

Improved understanding of rhizosphere chemistry will enhance our ability to model nutrient dynamics and on a broader scale, to develop effective management strategies for applied plant nutrients. With a controlled-climate study, we evaluated in situ changes in macro-nutrient concentrations in the rh...

Effects of the Integration of Sunn Hemp and Soil Solarization on Plant-Parasitic and Free-Living Nematodes

PubMed Central

Marahatta, Sharadchandra P.; Wang, Koon-Hui; Sipes, Brent S.; Hooks, Cerruti R. R.

2012-01-01

Sunn hemp (SH), Crotolaria juncea, is known to suppress Rotylenchulus reniformis and weeds while enhancing free-living nematodes involved in nutrient cycling. Field trials were conducted in 2009 (Trial I) and 2010 (Trial II) to examine if SH cover cropping could suppress R. reniformis and weeds while enhancing free-living nematodes if integrated with soil solarization (SOL). Cover cropping of SH, soil solarization, and SH followed by SOL (SHSOL) were compared to weedy fallow control (C). Rotylenchulus reniformis population was suppressed by SHSOL at the end of cover cropping or solarization period (Pi) in Trial I, but not in Trial II. However, SOL and SHSOL did not suppress R. reniformis compared to SH in either trial. SH enhanced abundance of bacterivores and suppressed the % herbivores only at Pi in Trial II. At termination of the experiment, SH resulted in a higher enrichment index indicating greater soil nutrient availability, and a higher structure index indicating a less disturbed nematode community compared to C. SOL suppressed bacterivores and fungivores only in Trial II but not in Trial I. On the other hand, SHSOL enhanced bacterivores and fungivores only at Pi in Trial I. Weeds were suppressed by SH, SOL and SHSOL throughout the experiment. SHSOL suppressed R. reniformis and enhanced free-living nematodes better than SOL, and suppressed weeds better than SH. PMID:23482700

WATERSHEED NUTRIENT INPUTS, PHYTOPLANKTON ACCUMULATION, AND C STOCKS IN CHESAPEAKE BAY

EPA Science Inventory

Inputs of N and P to Chesapeake Bay have been enhanced by anthropogenic activities. Fertilizers, developed areas, N emissions, and industrial effluents contribute to point and diffuse sources currently 2-20X higher than those from undisturbed watersheds. Enhanced nutrient inputs ...

Role of microbial inoculation and industrial by-product phosphogypsum in growth and nutrient uptake of maize (Zea mays L.) grown in calcareous soil.

PubMed

Al-Enazy, Abdul-Aziz R; Al-Oud, Saud S; Al-Barakah, Fahad N; Usman, Adel Ra

2017-08-01

Alkaline soils with high calcium carbonate and low organic matter are deficient in plant nutrient availability. Use of organic and bio-fertilizers has been suggested to improve their properties. Therefore, a greenhouse experiment was conducted to evaluate the integrative role of phosphogypsum (PG; added at 0.0, 10, 30, and 50 g PG kg -1 ), cow manure (CM; added at 50 g kg -1 ) and mixed microbial inoculation (Incl.; Azotobacter chroococcum, and phosphate-solubilizing bacteria Bacillus megaterium var. phosphaticum and Pseudomonas fluorescens) on growth and nutrients (N, P, K, Fe, Mn, Zn and Cu) uptake of maize (Zea mays L.) in calcareous soil. Treatment effects on soil chemical and biological properties and the Cd and Pb availability to maize plants were also investigated. Applying PG decreased soil pH. The soil available P increased when soil was inoculated and/or treated with CM, especially with PG. The total microbial count and dehydrogenase activity were enhanced with PG+CM+Incl. Inoculated soils treated with PG showed significant increases in NPK uptake and maize plant growth. However, the most investigated treatments showed significant decreases in shoot micronutrients. Cd and Pb were not detected in maize shoots. Applying PG with microbial inoculation improved macronutrient uptake and plant growth. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Spatial variability assessment of soil nutrients in an intense agricultural area, a case study of Rugao County in Yangtze River Delta Region, China

NASA Astrophysics Data System (ADS)

Zhao, Yongcun; Xu, Xianghua; Darilek, Jeremy Landon; Huang, Biao; Sun, Weixia; Shi, Xuezheng

2009-05-01

Topsoil samples (0-20 cm) ( n = 237) were collected from Rugao County, China. Geostatistical variogram analysis, sequential Gaussian simulation (SGS), and principal component (PC) analysis were applied to assess spatial variability of soil nutrients, identify the possible areas of nutrient deficiency, and explore spatial scale of variability of soil nutrients in the county. High variability of soil nutrient such as soil organic matter (SOM), total nitrogen (TN), available P, K, Fe, Mn, Cu, Zn, and B concentrations were observed. Soil nutrient properties displayed significant differences in their spatial structures, with available Cu having strong spatial dependence, SOM and available P having weak spatial dependence, and other nutrient properties having moderate spatial dependence. The soil nutrient deficiency, defined here as measured nutrient concentrations which do not meet the advisory threshold values specific to the county for dominant crops, namely rice, wheat, and rape seeds, was observed in available K and Zn, and the deficient areas covered 38 and 11%, respectively. The first three PCs of the nine soil nutrient properties explained 62.40% of the total variance. TN and SOM with higher loadings on PC1 are closely related to soil texture derived from different parent materials. The PC2 combined intermediate response variables such as available Zn and P that are likely to be controlled by land use and soil pH. Available B has the highest loading on PC3 and its variability of concentrations may be primarily ascribed to localized anthropogenic influence. The amelioration of soil physical properties (i.e. soil texture) and soil pH may improve the availability of soil nutrients and the sustainability of the agricultural system of Rugao County.

Microbial dynamics and enzyme activities in tropical Andosols depending on land use and nutrient inputs

NASA Astrophysics Data System (ADS)

Mganga, Kevin; Razavi, Bahar; Kuzyakov, Yakov

2015-04-01

Microbial decomposition of soil organic matter is mediated by enzymes and is a key source of terrestrial CO2 emissions. Microbial and enzyme activities are necessary to understand soil biochemical functioning and identify changes in soil quality. However, little is known about land use and nutrients availability effects on enzyme activities and microbial processes, especially in tropical soils of Africa. This study was conducted to examine how microbial and enzyme activities differ between different land uses and nutrient availability. As Andosols of Mt. Kilimanjaro are limited by nutrient concentrations, we hypothesize that N and P additions will stimulate enzyme activity. N and P were added to soil samples (0-20 cm) representing common land use types in East Africa: (1) savannah, (2) maize fields, (3) lower montane forest, (4) coffee plantation, (5) grasslands and (6) traditional Chagga homegardens. Total CO2 efflux from soil, microbial biomass and activities of β-glucosidase, cellobiohydrolase, chitinase and phosphatase involved in C, N and P cycling, respectively was monitored for 60 days. Total CO2 production, microbial biomass and enzyme activities varied in the order forest soils > grassland soils > arable soils. Increased β-glucosidase and cellobiohydrolase activities after N addition of grassland soils suggest that microorganisms increased N uptake and utilization to produce C-acquiring enzymes. Low N concentration in all soils inhibited chitinase activity. Depending on land use, N and P addition had an inhibitory or neutral effect on phosphatase activity. We attribute this to the high P retention of Andosols and low impact of N and P on the labile P fractions. Enhanced CO2 production after P addition suggests that increased P availability could stimulate soil organic matter biodegradation in Andosols. In conclusion, land use and nutrients influenced soil enzyme activities and microbial dynamics and demonstrated the decline in soil quality after landuse change. Key words: Andosols, β-glucosidase, Cellobiohydrolase, Chitinase, Phosphatase, Mt. Kilimanjaro

Evolving urban water and residuals management paradigms: water reclamation and reuse, decentralization, and resource recovery.

PubMed

Daigger, Glen T

2009-08-01

Population growth and improving standards of living, coupled with dramatically increased urbanization, are placing increased pressures on available water resources, necessitating new approaches to urban water management. The tradition linear "take, make, waste" approach to managing water increasingly is proving to be unsustainable, as it is leading to water stress (insufficient water supplies), unsustainable resource (energy and chemicals) consumption, the dispersion of nutrients into the aquatic environment (especially phosphorus), and financially unstable utilities. Different approaches are needed to achieve economic, environmental, and social sustainability. Fortunately, a toolkit consisting of stormwater management/rainwater harvesting, water conservation, water reclamation and reuse, energy management, nutrient recovery, and source separation is available to allow more closed-loop urban water and resource management systems to be developed and implemented. Water conservation and water reclamation and reuse (multiple uses) are becoming commonplace in numerous water-short locations. Decentralization, enabled by new, high-performance treatment technologies and distributed stormwater management/rainwater harvesting, is furthering this transition. Likewise, traditional approaches to residuals management are evolving, as higher levels of energy recovery are desired, and nutrient recovery and reuse is to be enhanced. A variety of factors affect selection of the optimum approach for a particular urban area, including local hydrology, available water supplies, water demands, local energy and nutrient-management situations, existing infrastructure, and utility governance structure. A proper approach to economic analysis is critical to determine the most sustainable solutions. Stove piping (i.e., separate management of drinking, storm, and waste water) within the urban water and resource management profession must be eliminated. Adoption of these new approaches to urban water and resource management can lead to more sustainable solutions, defined as financially stable, using locally sustainable water supplies, energy-neutral, providing responsible nutrient management, and with access to clean water and appropriate sanitation for all.

Enhanced efficiency fertilisers: a review of formulation and nutrient release patterns.

PubMed

Timilsena, Yakindra Prasad; Adhikari, Raju; Casey, Phil; Muster, Tim; Gill, Harsharn; Adhikari, Benu

2015-04-01

Fertilisers are one of the most important elements of modern agriculture. The application of fertilisers in agricultural practices has markedly increased the production of food, feed, fuel, fibre and other plant products. However, a significant portion of nutrients applied in the field is not taken up by plants and is lost through leaching, volatilisation, nitrification, or other means. Such a loss increases the cost of fertiliser and severely pollutes the environment. To alleviate these problems, enhanced efficiency fertilisers (EEFs) are produced and used in the form of controlled release fertilisers and nitrification/urease inhibitors. The application of biopolymers for coating in EEFs, tailoring the release pattern of nutrients to closely match the growth requirement of plants and development of realistic models to predict the release pattern of common nutrients have been the foci of fertiliser research. In this context, this paper intends to review relevant aspects of new developments in fertiliser production and use, agronomic, economic and environmental drives for enhanced efficiency fertilisers and their formulation process and the nutrient release behaviour. Application of biopolymers and complex coacervation technique for nutrient encapsulation is also explored as a promising technology to produce EEFs. © 2014 Society of Chemical Industry.

Subsurface application enhances benefits of manure redistribution

USDA-ARS?s Scientific Manuscript database

Sustainable nutrient management requires redistribution of livestock manure from nutrient-excess areas to nutrient-deficit areas. Field experiments were conducted to assess agronomic and environmental effects of different poultry litter application methods (surface vs. subsurface) and timings (fall ...

Numerical Modeling of the Effects of Nutrient-rich Coastal-water Input on the Phytoplankton in the Gulf of California

NASA Astrophysics Data System (ADS)

Bermudez, A.; Rivas, D.

2015-12-01

Phytoplankton bloom dynamics depends on the interactions of favorable physical, chemical, and biotic conditions, particularly on the available nutrients that enhance phytoplankton growth, like nitrogen. Costal and estuarine environments are heavily influenced by exogenous sources of nitrogen; the anthropogenic inputs include urban and rural wastewater coming from agricultural activities (i.e., fertilizers and animal waste). In response, new production is often enhanced, leading eutrophication and phytoplankton blooms, including harmful taxa. These events have become more frequent, and with it the interest to evaluate their effects on marine ecosystems and the impact on human health. In the Gulf of California the harmful algal blooms (HABs) had affected aquaculture, fisheries, and even tourism, thereby it is important to generate information about biological and physical factors that can influence their appearance. A numerical model is a tool that may bring key information about the origin and distribution of phytoplankton blooms. Herein the analysis is based on a three-dimensional, hydrodynamical numerical model, coupled to a Nitrogen-Phytoplankton-Zooplankton-Detritus (NPZD) model. Several numerical simulations using different forcing and scenarios are carried out in order to evaluate the processes that influence the phytoplankton growth. These numerical results are compared to available observations. Thus, the main environmental factors triggering the generation of HABs can be identified.

Seabird guano enhances phytoplankton production in the Southern Ocean.

NASA Astrophysics Data System (ADS)

Shatova, Olga; Wing, Stephen; Hoffmann, Linn; Jack, Lucy; Gault-Ringold, Melanie

2015-04-01

Great congregations of seabirds in sub-Antarctic and Antarctic coastal areas result in delivery of nutrient-rich guano to marine ecosystems that potentially enhances productivity and supports biodiversity in the region. Guano-derived bio-available micronutrients and macronutrients might be utilized by marine phytoplankton for photosynthetic production, however, mechanisms and significance of guano fertilization in the Southern Ocean are largely understudied. Over austral summers of 2012 and 2013 we performed a series of guano-enrichment phytoplankton incubation experiments with water samples collected from three different water masses in the Southern Ocean: Antarctic waters of the Ross sea and sub-Antarctic waters offshore the Otago Peninsula, both showing iron limitation of phytoplankton productivity in summer, and in the subtropical frontal zone offshore from the Snares Islands, which is generally micronutrient-repleted. Samples were enriched with known concentrations of guano-derived nutrients. Phytoplankton biomass increased significantly in guano-treated samples during all three incubation experiments (7-10 fold increase), while remained low in control samples. This response indicates that seabird guano provides nutrients that limit primary production in the Southern Ocean and that these nutrients are readily taken up by phytoplankton. Guano additions were compared to Fe and Macronutrient treatments (both added in quantities similar to those in the guano treatment). Phytoplankton biomass increased significantly in response to the Macronutrient treatment in the subtropical frontal zone, however, the response had a smaller magnitude compared to the guano treatment (2.8 µgL-1 vs 5.2 µgL-1) ; there was no significant effect of Fe on phytoplankton growth. This suggests the potential importance of synergistic effects of nutrients in guano. Incubation with sub-Antarctic waters showed that Fe and Macronutrients might be equally important for enhancement of phytoplankton production. Analysis of phytoplankton community composition showed that Prymnesiophytes (in particular, Phaeocystis antarctica) dominated phytoplankton response in both sub-Antarctic waters and offshore the Snares islands. Simultaneously, significant increases in the number of diatoms and photosynthetic pico- and nanophytoplankton were observed. Our study elucidates the potential role of seabirds in supporting productivity in the Southern Ocean.

Epiphyte loads on seagrasses and microphytobenthos abundance are not reliable indicators of nutrient availability in oligotrophic coastal ecosystems.

PubMed

Fourqurean, James W; Muth, Meredith F; Boyer, Joseph N

2010-07-01

Despite marked gradients in nutrient availability that control the abundance and species composition of seagrasses in south Florida, and the importance of nutrient availability in controlling abundance and composition of epiphytes on seagrasses in other locations, we did not find that epiphyte load on the dominant seagrass, Thalassia testudinum, or that the relative contribution of algal epiphytes to the epiphyte community, was positively correlated with nutrient availability in the water column or the sediment in oligotrophic seagrass beds. Further, the abundance of microphytobenthos, as indicated by Chlorophyll-a concentration in the sediments, was not directly correlated with concentrations of nutrients in the sediments. Our results suggest that epiphyte and microphytobenthos abundance are not unambiguous indicators of nutrient availability in relatively pristine seagrass environments, and therefore would make poor candidates for indicators of the status and trends of seagrass ecosystems in relatively low-nutrient environments like the Florida Keys. Copyright 2010 Elsevier Ltd. All rights reserved.

Plants may alter competition by modifying nutrient bioavailability in rhizosphere: a modeling approach.

PubMed

Raynaud, Xavier; Jaillard, Benoît; Leadley, Paul W

2008-01-01

Plants modify nutrient availability by releasing chemicals in the rhizosphere. This change in availability induced by roots (bioavailability) is known to improve nutrient uptake by individual plants releasing such compounds. Can this bioavailability alter plant competition for nutrients and under what conditions? To address these questions, we have developed a model of nutrient competition between plant species based on mechanistic descriptions of nutrient diffusion, plant exudation, and plant uptake. The model was parameterized using data of the effects of root citrate exudation on phosphorus availability. We performed a sensitivity analysis for key parameters to test the generality of these effects. Our simulations suggest the following. (1) Nutrient uptake depends on the number of roots when nutrients and exudates diffuse little, because individual roots are nearly independent in terms of nutrient supply. In this case, bioavailability profits only species with exudates. (2) Competition for nutrients depends on the spatial arrangement of roots when nutrients diffuse little but exudates diffuse widely. (3) Competition for nutrients depends on the nutrient uptake capacity of roots when nutrients and exudates diffuse widely. In this case, bioavailability profits all species. Mechanisms controlling competition for bioavailable nutrients appear to be diverse and strongly depend on soil, nutrient, and plant properties.

Relating watershed nutrient loads to satellite derived estuarine water quality

EPA Science Inventory

Nutrient enhanced phytoplankton production is a cause of degraded estuarine water quality. Yet, relationships between watershed nutrient loads and the spatial and temporal scales of phytoplankton blooms and subsequent water quality impairments remain unquantified for most systems...

Soil bacterial community response to vegetation succession after fencing in the grassland of China.

PubMed

Zeng, Quanchao; An, Shaoshan; Liu, Yang

2017-12-31

Natural succession is an important process in terrestrial system, playing an important role in enhancing soil quality and plant diversity. Soil bacteria is the linkage between soil and plant, has an important role in aboveground community dynamics and ecosystem functioning in terrestrial ecosystems, driving the decomposition of soil organic matter and plant litter. However, the role of soil bacteria in the secondary succession has not been well understood, particularly in the degraded soil of Loess Plateau. In this study, we investigated soil nutrients and soil bacterial community during the secondary succession after a long-term fencing in the grassland, in the Yuwu Mountain, northwest China. The chronosequence included 1year, 12years, 20years and 30years. The soil bacterial community composition was determined by the Illumina HiSeq sequencing method. The data showed that soil bacterial diversity had no significant changes along the chronosequence, but soil bacterial community compositions significantly changed. Proteobacteria, Acidobacteria and Actinobacteria were the main phyla in all the samples across succession. With the accumulation of soil organic matter and nutrients, the relative abundance of Actinobacteria decreased, whereas Proteobacteria increased. These shifts may be caused by the increase of the available nutrients across the secondary succession. In the younger sites, soils were dominated by oligotrophic groups, whereas soil in the late-succession site were dominated by copiotrophic groups, indicating the dependence of soil bacterial community composition on the contents of soil available nutrients. Copyright © 2017 Elsevier B.V. All rights reserved.

Interactions between accumulation of trace elements and major nutrients in Salix caprea after inoculation with rhizosphere microorganisms

PubMed Central

De Maria, Susanna; Rivelli, Anna Rita; Kuffner, Melanie; Sessitsch, Angela; Wenzel, Walter W.; Gorfer, Markus; Strauss, Joseph; Puschenreiter, Markus

2015-01-01

Although the beneficial effects on growth and trace element accumulation in Salix inoculated with microbes are well known, little information is available on the interactions among trace elements and major nutrients. The main purpose of this study was to assess the effect of inoculation with rhizobacteria Agromyces sp. AR33, Streptomyces sp. AR17, and the combination of each of them with the fungus Cadophora finlandica PRF15 on biomass production and the accumulation of selected trace elements and major nutrients (Cd, Zn, Fe, Ca, K and Mg) in Salix caprea grown on a moderately polluted soil. Dry matter production was significantly enhanced only upon inoculation with Agromyces AR33. Microbial treatments differently affected the accumulation of Zn and Cd in plants. Both the inoculation with Streptomyces AR17 and the co-inoculation of C. finlandica with Agromyces AR33 were most efficient in enhancing the accumulation of Zn and Cd in leaves. These two treatments showed also a higher translocation factor from roots to the leaves for both Cd and Zn. Concentrations of major nutrients in shoots were generally increased in the treatments with the fungus compared to those without, except for K in plants inoculated with bacterial strain Streptomyces AR17. Co-inoculation of C. finlandica plus Agromyces AR33 resulted in a better accumulation of both Zn and Cd and Ca, K and Mg in shoots. This study suggests that the phytoextraction of Zn and Cd can be improved by inoculation with selected microbial strains. PMID:21612812

A critical review on fungi mediated plant responses with special emphasis to Piriformospora indica on improved production and protection of crops.

PubMed

Ansari, Mohammad Wahid; Trivedi, Dipesh Kumar; Sahoo, Ranjan Kumar; Gill, Sarvajeet Singh; Tuteja, Narendra

2013-09-01

The beneficial fungi are potentially useful in agriculture sector to avail several services to crop plants such as water status, nutrient enrichment, stress tolerance, protection, weed control and bio-control. Natural agro-ecosystem relies on fungi because of it takes part in soil organic matter decomposition, nutrient acquisition, organic matter recycling, nutrient recycling, antagonism against plant pests, and crop management. The crucial role of fungi in normalizing the toxic effects of phenols, HCN and ROS by β-CAS, ACC demainase and antioxidant enzymes in plants is well documented. Fungi also play a part in various physiological processes such as water uptake, stomatal movement, mineral uptake, photosynthesis and biosynthesis of lignan, auxins and ethylene to improve growth and enhance plant fitness to cope heat, cold, salinity, drought and heavy metal stress. Here, we highlighted the ethylene- and cyclophilin A (CypA)-mediated response of Piriformospora indica for sustainable crop production under adverse environmental conditions. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Nutrient recovery from apple pomace waste by vermicomposting technology.

PubMed

Hanc, Ales; Chadimova, Zuzana

2014-09-01

The present work was focused on vermicomposting apple pomace waste and its mixtures with straw in volume proportions of 25%, 50%, and 75%. The feasibility was evaluated on the basis of agrochemical properties and earthworm biomass. Vermicomposting was able to reduce the weight and volume of the feedstock by 65% and 85%, respectively. The resulting vermicomposts were characterized by slightly acidic to neutral pH (5.9-6.9), and optimal EC (1.6-4.4mS/cm) and C:N ratios (13-14). The total content of nutrients increased during vermicomposting for all of the treatments with the following average final values: N=2.8%, P=0.85%, K=2.3%, and Mg=0.38%. The addition of straw to apple pomace did not enhance earthworm biomass, but did increase the available content of nutrients during vermicomposting. The data reveals that vermicomposting is a suitable technology for the decomposition of apple pomace waste into a value added product. Copyright © 2014 Elsevier Ltd. All rights reserved.

Efflux of hydraulically lifted water from mycorrhizal fungal hyphae during imposed drought

PubMed Central

Querejeta, José Ignacio; Allen, Michael F

2008-01-01

Apart from improving plant and soil water status during drought, it has been suggested that hydraulic lift (HL) could enhance plant nutrient capture through the flow of mineral nutrients directly from the soil to plant roots, or by maintaining the functioning of mycorrhizal fungi. We evaluated the extent to which the diel cycle of water availability created by HL covaries with the efflux of HL water from the tips of extramatrical (external) mycorrhizal hyphae, and the possible effects on biogeochemical processes. Phenotypic mycorrhizal fungal variables, such as total and live hyphal lengths, were positively correlated with HL efflux from hyphae, soil water potential (dawn), and plant response variables (foliar 15N). The efflux of HL water from hyphae was also correlated with bacterial abundance and soil enzyme activity (P), and the moistening of soil organic matter. Such findings indicate that the efflux of HL water from the external mycorrhizal mycelia may be a complementary explanation for plant nutrient acquisition and survival during drought. PMID:19704776

Effect of the nutritional status of semi-continuous microalgal cultures on the productivity and biochemical composition of Brachionus plicatilis.

PubMed

Ferreira, Martiña; Seixas, Pedro; Coutinho, Paula; Fábregas, Jaime; Otero, Ana

2011-12-01

The rotifer Brachionus plicatilis was cultured using the microalga Isochrysis aff. galbana clone T-ISO as feed. T-ISO was cultured semi-continuously with daily renewal rates of 10%, 20%, 30%, 40%, and 50% of the volume of cultures. The increase of renewal rate led to increasing nutrient and light availability in microalgal cultures, which caused differences in the biochemical composition of microalgal biomass. Growth rate, individual dry weight, organic content, and biomass productivity of rotifer cultures increased in response to higher growth rate in T-ISO cultures. Rotifer growth rate showed a strong negative correlation (R² = 0.90) with the C/N ratio of microalgal biomass. Rotifer dry weight was also affected by nutrient availability of T-ISO cultures, increasing up to 50% from nutrient-limited to nutrient-sufficient conditions. Consequently, biomass productivity of rotifer cultures increased more than twofold with the increase of renewal rate of T-ISO cultures. Rotifer organic content underwent the same trend of total dry weight. Maximum content of polyunsaturated fatty acids was reached in rotifers fed T-ISO from the renewal rate of 40%, with percentages of docosahexaenoic acid (22:6ω-3, DHA) and eicosapentaenoic acid (20:5ω-3, EPA) of 11% and 5% of total fatty acids, respectively. Selecting the most appropriate conditions for microalgal culture can therefore enhance the nutritive quality of microalgal biomass, resulting in a better performance of filter feeders and their nutrient content, and may constitute a useful tool to improve the rearing of fish larvae and other aquaculture organisms that require live feed in some or all the stages of their life cycle.

Organic wastes from bioenergy and ecological sanitation as soil fertility improver: a field experiment in a tropical Andosol

NASA Astrophysics Data System (ADS)

Krause, A.; Nehls, T.; George, E.; Kaupenjohann, M.

2015-11-01

Andosols require the regular application of phosphorus (P) to sustain crop productivity. In a practice oriented field experiment at an Andosol site in NW Tanzania, the effects of various soil amendments (standard compost, urine, biogas slurry and CaSa-compost [biochar and sanitized human excreta]) on (i) the productivity of locally grown crop species, on (ii) the plants' nutrient status and on (iii) the soil's physico-chemical properties were studied. None of the amendments had any significant effect on soil moisture, so the observed variation in crop yield and plant nutrition reflected differences in nutrient availability. The application of CaSa-compost increased the level of available P in the top-soil from 0.5 to 4.4 mg kg-1 and the soil pH from 5.3 to 5.9. Treatment with biogas slurry, standard compost and CaSa-compost increased the above-ground biomass of Zea mays by, respectively, 140, 154 and 211 %. The grain yields of maize on soil treated with biogas slurry, standard compost and CaSa-compost were, respectively, 2.63, 3.18 and 4.40 t ha-1, compared to only 1.10 t ha-1 on unamended plots. All treatments enhanced crop productivity and increased the uptake of nutrients into the maize grains. The CaSa-compost was especially effective in mitigating P deficiency and soil acidification. We conclude that all treatments are viable as substitute for synthetic fertilizers. However, further steps are required to integrate the tested soil amendments into farm-scale nutrient management and to balance the additions and removals of nutrients, so that the loop can be closed.

The effect of nitrogen availability and water conditions on competition between a facultative CAM plant and an invasive grass.

PubMed

Yu, Kailiang; D'Odorico, Paolo; Carr, David E; Personius, Ashden; Collins, Scott L

2017-10-01

Plants with crassulacean acid metabolism (CAM) are increasing their abundance in drylands worldwide. The drivers and mechanisms underlying the increased dominance of CAM plants and CAM expression (i.e., nocturnal carboxylation) in facultative CAM plants, however, remain poorly understood. We investigated how nutrient and water availability affected competition between Mesembryanthemum crystallinum (a model facultative CAM species) and the invasive C 3 grass Bromus mollis that co-occur in California's coastal grasslands. Specifically we investigated the extent to which water stress, nutrients, and competition affect nocturnal carboxylation in M. crystallinum . High nutrient and low water conditions favored M. crystallinum over B. mollis , in contrast to high water conditions. While low water conditions induced nocturnal carboxylation in 9-week-old individuals of M. crystallinum , in these low water treatments, a 66% reduction in nutrient applied over the entire experiment did not further enhance nocturnal carboxylation. In high water conditions M. crystallinum both alone and in association with B. mollis did not perform nocturnal carboxylation, regardless of the nutrient levels. Thus, nocturnal carboxylation in M. crystallinum was restricted by strong competition with B. mollis in high water conditions. This study provides empirical evidence of the competitive advantage of facultative CAM plants over grasses in drought conditions and of the restricted ability of M. crystallinum to use their photosynthetic plasticity (i.e., ability to switch to CAM behavior) to compete with grasses in well-watered conditions. We suggest that a high drought tolerance could explain the increased dominance of facultative CAM plants in a future environment with increased drought and nitrogen deposition, while the potential of facultative CAM plants such as M. crystallinum to expand to wet environments is expected to be limited.

Plant–herbivore–decomposer stoichiometric mismatches and nutrient cycling in ecosystems

PubMed Central

Cherif, Mehdi; Loreau, Michel

2013-01-01

Plant stoichiometry is thought to have a major influence on how herbivores affect nutrient availability in ecosystems. Most conceptual models predict that plants with high nutrient contents increase nutrient excretion by herbivores, in turn raising nutrient availability. To test this hypothesis, we built a stoichiometrically explicit model that includes a simple but thorough description of the processes of herbivory and decomposition. Our results challenge traditional views of herbivore impacts on nutrient availability in many ways. They show that the relationship between plant nutrient content and the impact of herbivores predicted by conceptual models holds only at high plant nutrient contents. At low plant nutrient contents, the impact of herbivores is mediated by the mineralization/immobilization of nutrients by decomposers and by the type of resource limiting the growth of decomposers. Both parameters are functions of the mismatch between plant and decomposer stoichiometries. Our work provides new predictions about the impacts of herbivores on ecosystem fertility that depend on critical interactions between plant, herbivore and decomposer stoichiometries in ecosystems. PMID:23303537

Energy and carbohydrate for training and recovery.

PubMed

Burke, Louise M; Loucks, Anne B; Broad, Nick

2006-07-01

Soccer players should achieve an energy intake that provides sufficient carbohydrate to fuel the training and competition programme, supplies all nutrient requirements, and allows manipulation of energy or nutrient balance to achieve changes in lean body mass, body fat or growth. Although the traditional culture of soccer has focused on carbohydrate intake for immediate match preparation, top players should adapt their carbohydrate intake on a daily basis to ensure adequate fuel for training and recovery between matches. For players with a mobile playing style, there is sound evidence that dietary programmes that restore and even super-compensate muscle glycogen levels can enhance activity patterns during matches. This will presumably also benefit intensive training, such as twice daily practices. As well as achieving a total intake of carbohydrate commensurate with fuel needs, the everyday diet should promote strategic intake of carbohydrate and protein before and after key training sessions to optimize the adaptations and enhance recovery. The achievement of the ideal physique for soccer is a long-term goal that should be undertaken over successive years, and particularly during the off-season and pre-season. An increase in lean body mass or a decrease in body fat is the product of a targeted training and eating programme. Consultation with a sports nutrition expert can assist soccer players to manipulate energy and nutrient intake to meet such goals. Players should be warned against the accidental or deliberate mismatch of energy intake and energy expenditure, such that energy availability (intake minus the cost of exercise) falls below 125 kJ (30 kcal) per kilogram of fat-free mass per day. Such low energy availability causes disturbances to hormonal, metabolic, and immune function.

Cyclodextrin enhanced biodegradation of polycyclic aromatic hydrocarbons and phenols in contaminated soil slurries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ian J. Allan; Kirk T. Semple; Rina Hare

This work aimed to evaluate the relative contribution of soil catabolic activity, contaminant bioaccessibility, and nutrient levels on the biodegradation of field-aged polycyclic aromatic hydrocarbons and phenolic compounds in three municipal gas plant site soils. Extents of biodegradation achieved, in 6 week-long soil slurry assays, under the following conditions were compared: (i) with inoculation of catabolically active PAH and phenol-degrading microorganisms, (ii) with and without hydroxypropyl-{beta}-cyclodextrin supplementation (HPCD; 100 g L{sup -1}), and finally (iii) with the provision of additional inorganic nutrients in combination with HPCD. Results indicated no significant (p {lt} 0.05) differences between biodegradation endpoints attained in treatmentsmore » inoculated with catabolically active microorganisms as compared with the uninoculated control. Amendments with HPCD significantly (p {lt} 0.05) lowered biodegradation endpoints for most PAHs and phenolic compounds. Only in one soil did the combination of HPCD and nutrients consistently achieve better bioremediation endpoints with respect to the HPCD-only treatments. Thus, for most compounds, biodegradation was not limited by the catabolic activity of the indigenous microorganisms but rather by processes resulting in limited availability of contaminants to degraders. It is therefore suggested that the bioremediation of PAH and phenol impacted soils could be enhanced through HPCD amendments. In addition, the biodegradability of in situ and spiked (deuterated analogues) PAHs following 120 days aging of the soils suggested that this contact time was not sufficient to obtain similar partitions to that observed for field-aged contaminants; with the spiked compounds being significantly (p {lt} 0.05) more available for biodegradation. 42 refs., 5 figs., 2 tabs.« less

The effect of pH on phosphorus availability and speciation in an aquaponics nutrient solution.

PubMed

Cerozi, Brunno da Silva; Fitzsimmons, Kevin

2016-11-01

The interaction between the main ions in aquaponics nutrient solutions affects chemical composition and availability of nutrients, and nutrient uptake by plant roots. This study determined the effect of pH on phosphorus (P) speciation and availability in an aquaponics nutrient solution and used Visual MINTEQ to simulate P species and P activity. In both experimental and simulated results, P availability decreased with increase in pH of aquaponics nutrient solutions. According to simulations, P binds to several cations leaving less free phosphate ions available in solution. High pH values resulted in the formation of insoluble calcium phosphate species. The study also demonstrated the importance of organic matter and alkalinity in keeping free phosphate ions in solution at high pH ranges. It is recommended though that pH in aquaponics systems is maintained at a 5.5-7.2 range for optimal availability and uptake by plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

FORAGES AND PASTURES SYMPOSIUM: Improving soil health and productivity on grasslands using managed grazing of livestock.

PubMed

Russell, J R; Bisinger, J J

2015-06-01

Beyond grazing, managed grasslands provide ecological services that may offer economic incentives for multifunctional use. Increasing biodiversity of plant communities may maximize net primary production by optimizing utilization of available light, water, and nutrient resources; enhance production stability in response to climatic stress; reduce invasion of exotic species; increase soil OM; reduce nutrient leaching or loading in surface runoff; and provide wildlife habitat. Strategically managed grazing may increase biodiversity of cool-season pastures by creating disturbance in plant communities through herbivory, treading, nutrient cycling, and plant seed dispersal. Soil OM will increase carbon and nutrient sequestration and water-holding capacity of soils and is greater in grazed pastures than nongrazed grasslands or land used for row crop or hay production. However, results of studies evaluating the effects of different grazing management systems on soil OM are limited and inconsistent. Although roots and organic residues of pasture forages create soil macropores that reduce soil compaction, grazing has increased soil bulk density or penetration resistance regardless of stocking rates or systems. But the effects of the duration of grazing and rest periods on soil compaction need further evaluation. Because vegetative cover dissipates the energy of falling raindrops and plant stems and tillers reduce the rate of surface water flow, managing grazing to maintain adequate vegetative cover will minimize the effects of treading on water infiltration in both upland and riparian locations. Through increased diversity of the plant community with alterations of habitat structure, grazing systems can be developed that enhance habitat for wildlife and insect pollinators. Although grazing management may enhance the ecological services provided by grasslands, environmental responses are controlled by variations in climate, soil, landscape position, and plant community resulting in considerable spatial and temporal variation in the responses. Furthermore, a single grazing management system may not maximize livestock productivity and each of the potential ecological services provided by grasslands. Therefore, production and ecological goals must be integrated to identify the optimal grazing management system.

Enhancement of microbial 2,4,6-trinitrotoluene transformation with increased toxicity by exogenous nutrient amendment.

PubMed

Liang, Shih-Hsiung; Hsu, Duen-Wei; Lin, Chia-Ying; Kao, Chih-Ming; Huang, Da-Ji; Chien, Chih-Ching; Chen, Ssu-Ching; Tsai, Isheng Jason; Chen, Chien-Cheng

2017-04-01

In this study, the bacterial strain Citrobacter youngae strain E4 was isolated from 2,4,6-trinitrotoluene (TNT)-contaminated soil and used to assess the capacity of TNT transformation with/without exogenous nutrient amendments. C. youngae E4 poorly degraded TNT without an exogenous amino nitrogen source, whereas the addition of an amino nitrogen source considerably increased the efficacy of TNT transformation in a dose-dependent manner. The enhanced TNT transformation of C. youngae E4 was mediated by increased cell growth and up-regulation of TNT nitroreductases, including NemA, NfsA and NfsB. This result indicates that the increase in TNT transformation by C. youngae E4 via nitrogen nutrient stimulation is a cometabolism process. Consistently, TNT transformation was effectively enhanced when C. youngae E4 was subjected to a TNT-contaminated soil slurry in the presence of an exogenous amino nitrogen amendment. Thus, effective enhancement of TNT transformation via the coordinated inoculation of the nutrient-responsive C. youngae E4 and an exogenous nitrogen amendment might be applicable for the remediation of TNT-contaminated soil. Although the TNT transformation was significantly enhanced by C. youngae E4 in concert with biostimulation, the 96-h LC50 value of the TNT transformation product mixture on the aquatic invertebrate Tigriopus japonicas was higher than the LC50 value of TNT alone. Our results suggest that exogenous nutrient amendment can enhance microbial TNT transformation; however, additional detoxification processes may be needed due to the increased toxicity after reduced TNT transformation. Copyright © 2016 Elsevier Inc. All rights reserved.

Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean

NASA Astrophysics Data System (ADS)

Ezzat, Leïla; Maguer, Jean-François; Grover, Renaud; Ferrier-Pagès, Christine

2016-08-01

During the 20th century, seawater temperatures have significantly increased, leading to profound alterations in biogeochemical cycles and ecosystem processes. Elevated temperatures have also caused massive bleaching (symbiont/pigment loss) of autotrophic symbioses, such as in coral-dinoflagellate association. As symbionts provide most nutrients to the host, their expulsion during bleaching induces host starvation. However, with the exception of carbon, the nutritional impact of bleaching on corals is still unknown, due to the poorly understood requirements in inorganic nutrients during stress. We therefore assessed the uptake rates of nitrogen and phosphate by five coral species maintained under normal and thermal stress conditions. Our results showed that nitrogen acquisition rates were significantly reduced during thermal stress, while phosphorus uptake rates were significantly increased in most species, suggesting a key role of this nutrient. Additional experiments showed that during thermal stress, phosphorus was required to maintain symbiont density and photosynthetic rates, as well as to enhance the translocation and retention of carbon within the host tissue. These findings shed new light on the interactions existing between corals and inorganic nutrients during thermal stress, and highlight the importance of phosphorus for symbiont health.

Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean.

PubMed

Ezzat, Leïla; Maguer, Jean-François; Grover, Renaud; Ferrier-Pagès, Christine

2016-08-17

During the 20(th) century, seawater temperatures have significantly increased, leading to profound alterations in biogeochemical cycles and ecosystem processes. Elevated temperatures have also caused massive bleaching (symbiont/pigment loss) of autotrophic symbioses, such as in coral-dinoflagellate association. As symbionts provide most nutrients to the host, their expulsion during bleaching induces host starvation. However, with the exception of carbon, the nutritional impact of bleaching on corals is still unknown, due to the poorly understood requirements in inorganic nutrients during stress. We therefore assessed the uptake rates of nitrogen and phosphate by five coral species maintained under normal and thermal stress conditions. Our results showed that nitrogen acquisition rates were significantly reduced during thermal stress, while phosphorus uptake rates were significantly increased in most species, suggesting a key role of this nutrient. Additional experiments showed that during thermal stress, phosphorus was required to maintain symbiont density and photosynthetic rates, as well as to enhance the translocation and retention of carbon within the host tissue. These findings shed new light on the interactions existing between corals and inorganic nutrients during thermal stress, and highlight the importance of phosphorus for symbiont health.

Parent's responses to nutrient claims and sports celebrity endorsements on energy-dense and nutrient-poor foods: an experimental study.

PubMed

Dixon, Helen; Scully, Maree; Wakefield, Melanie; Kelly, Bridget; Chapman, Kathy; Donovan, Robert

2011-06-01

To assess parents' responses to common, potentially misleading strategies for marketing energy-dense and nutrient-poor (EDNP) child-oriented foods. Between-subjects online experiment to test whether nutrient claims and sports celebrity endorsements on the front of packs of EDNP products lead parents to prefer and rate these foods more favourably. Australia. A total of 1551 parents of children aged 5-12 years, who were the main household grocery buyers. Inclusion of nutrient claims or sports celebrity endorsements on EDNP products led parents to perceive these products to be more nutritious than if they did not include such promotions. When asked to choose between a pair of different products (EDNP v. healthier), 56 % of parents did not read a nutrition information panel (NIP) before making their choice and this did not differ by promotion condition. These parents were more likely to choose an EDNP product if it included a nutrient claim (OR = 1.83, 95 % CI 1.31, 2.56; P < 0.001) or sports celebrity endorsement (OR = 2.37, 95 % CI 1.70, 3.32; P < 0.001). Sports celebrity endorsements also enhanced parent's perceptions of typical consumers of the product, perceptions of product healthiness and quality, as well as purchase intentions. Nutrient claims and sports celebrity endorsements tip consumer preferences towards EDNP products bearing such promotions, especially among the majority who do not read the NIP. As parents largely determine what foods are available to children at home, it is critical that initiatives aimed at reducing the persuasive impact of food marketing include this target group.

Soluble dust as source of nutrients to the oceans and the role of humans

NASA Astrophysics Data System (ADS)

Tsigaridis, K.; Kanakidou, M.; Myriokefalitakis, S.; Nikolaou, P.; Daskalakis, N.; Theodosi, C.; Nenes, A.; Mihalopoulos, N.

2014-12-01

Atmospheric deposition of trace constituents, both of natural and anthropogenic origin, can act as a nutrient source into the open ocean and affect marine ecosystem functioning and subsequently the exchange of CO2 between the atmosphere and the global ocean. Dust is known as a major source of nutrients (Fe and P) into the atmosphere, but only a fraction of these nutrients is released in soluble form that can be assimilated by the ecosystems. Dust is also known to enhance N deposition by interacting with anthropogenic pollutants and neutralisation of part of the acidity of the atmosphere by crustal alkaline species. The link between the soluble iron (Fe) and phosphorus (P) atmospheric deposition and atmospheric acidity, as well as anthropogenic sources, is investigated. The global atmospheric Fe, P and N cycle are parameterized in the global 3-D chemical transport model TM4-ECPL. Both primary emissions of total and soluble Fe and P associated with dust and combustion processes are taken into account, as well as inorganic and organic N emissions. The impact of atmospheric acidity on nutrient solubility is parameterised based on experimental findings. The model results are evaluated by comparison with available observations. The impact of air-quality changes on soluble nutrient deposition is studied by performing sensitivity simulations using preindustrial, present and future emission scenarios. The response of the chemical composition of nutrient-containing aerosols to environmental changes is demonstrated and quantified. This work has been supported by ARISTEIA - PANOPLY grant co-financed by European Union (ESF) and Greek national funds NSRF.

Enhancing nitrogen use efficiency of cereal crops by optimizing temperature, moisture, balanced nutrients, and oxygen bioavailability

USDA-ARS?s Scientific Manuscript database

Enhancement of nutrient use efficiency is imperative for increasing economic returns and reduction of environmental pollution caused by fertilization in crop production systems. In this paper, we have demonstrated at a given soil temperature and nitrogen (N) rate, N loss via ammonia (NH3) emission f...

NUTRIENTS IN WATERSHEDS; DEVELOPING ENHANCED MODELING TOOLS

EPA Science Inventory

Nutrient enrichment is one of the most detrimental stressors causing water-resource impairment. Of systems surveyed and reported as impaired, 40% of rivers, 51% of lakes, and 57% of estuaries listed nutrients as a primary cause of impairment (USEPA, 1996). In many cases, these ...

Soil Microbial Properties and Plant Growth Responses to Carbon and Water Addition in a Temperate Steppe: The Importance of Nutrient Availability

PubMed Central

Guo, Chengyuan; Wang, Renzhong; Xiao, Chunwang

2012-01-01

Background Global climatic change is generally expected to stimulate net primary production, and consequently increase soil carbon (C) input. The enhanced C input together with potentially increased precipitation may affect soil microbial processes and plant growth. Methodology/Principal Findings To examine the effects of C and water additions on soil microbial properties and plant growth, we conducted an experiment lasting two years in a temperate steppe of northeastern China. We found that soil C and water additions significantly affected microbial properties and stimulated plant growth. Carbon addition significantly increased soil microbial biomass and activity but had a limited effect on microbial community structure. Water addition significantly increased soil microbial activity in the first year but the response to water decreased in the second year. The water-induced changes of microbial activity could be ascribed to decreased soil nitrogen (N) availability and to the shift in soil microbial community structure. However, no water effect on soil microbial activity was visible under C addition during the two years, likely because C addition alleviated nutrient limitation of soil microbes. In addition, C and water additions interacted to affect plant functional group composition. Water addition significantly increased the ratio of grass to forb biomass in C addition plots but showed only minor effects under ambient C levels. Our results suggest that soil microbial activity and plant growth are limited by nutrient (C and N) and water availability, and highlight the importance of nutrient availability in modulating the responses of soil microbes and plants to potentially increased precipitation in the temperate steppe. Conclusions/Significance Increased soil C input and precipitation would show significant effects on soil microbial properties and plant growth in the temperate steppe. These findings will improve our understanding of the responses of soil microbes and plants to the indirect and direct climate change effects. PMID:22496905

Using membrane transporters to improve crops for sustainable food production

PubMed Central

Schroeder, Julian I.; Delhaize, Emmanuel; Frommer, Wolf B.; Guerinot, Mary Lou; Harrison, Maria J.; Herrera-Estrella, Luis; Horie, Tomoaki; Kochian, Leon V.; Munns, Rana; Nishizawa, Naoko K.; Tsay, Yi-Fang; Sanders, Dale

2013-01-01

With the global population predicted to grow by at least 25 per cent by 2050, the need for sustainable production of nutritious foods is critical for human and environmental health. Recent advances show that specialized plant membrane transporters can be used to enhance yields of staple crops, increase nutrient content and increase resistance to key stresses, including salinity, pathogens and aluminium toxicity, which in turn could expand available arable land. PMID:23636397

Counterintuitive effects of global warming-induced wind patterns on primary production in the Northern Humboldt Current System.

PubMed

Mogollón, Rodrigo; R Calil, Paulo H

2018-07-01

It has been hypothesized that global warming will strengthen upwelling-favorable winds in the Northern Humboldt Current System (NHCS) as a consequence of the increase of the land-sea thermal gradient along the Peruvian coast. The effect of strengthened winds in this region is assessed with the use of a coupled physical-biogeochemical model forced with projected and climatological winds. Strengthened winds induce an increase in primary production of 2% per latitudinal degree from 9.5°S to 5°S. In some important coastal upwelling sites primary production is reduced. This is due to a complex balance between nutrient availability, nutrient use efficiency, as well as eddy- and wind-driven factors. Mesoscale activity induces a net offshore transport of inorganic nutrients, thus reducing primary production in the coastal upwelling region. Wind mixing, in general disadvantageous for primary producers, leads to shorter residence times in the southern and central coastal zones. Overall, instead of a proportional enhancement in primary production due to increased winds, the NHCS becomes only 5% more productive (+5 mol C m -2 year -1 ), 10% less limited by nutrients and 15% less efficient due to eddy-driven effects. It is found that regions with a initial strong nutrient limitation are more efficient in terms of nutrient assimilation which makes them more resilient in face of the acceleration of the upwelling circulation. © 2018 John Wiley & Sons Ltd.

Sagebrush wildfire effects on surface soil nutrient availability: A temporal and spatial study

USDA-ARS?s Scientific Manuscript database

Wildfires occurring in Artemisia (sagebrush) ecosystems can temporarily increase soil nutrient availability in surface soil. Less is known, however, on how soil nutrient availability changes over time and microsite location post-wildfire. In Oct., 2013 a wildfire approximately 30 km north of Reno, N...

Inter-annual changes in detritus-based food chains can enhance plant growth response to elevated atmospheric CO2.

PubMed

Hines, Jes; Eisenhauer, Nico; Drake, Bert G

2015-12-01

Elevated atmospheric CO2 generally enhances plant growth, but the magnitude of the effects depend, in part, on nutrient availability and plant photosynthetic pathway. Due to their pivotal role in nutrient cycling, changes in abundance of detritivores could influence the effects of elevated atmospheric CO2 on essential ecosystem processes, such as decomposition and primary production. We conducted a field survey and a microcosm experiment to test the influence of changes in detritus-based food chains on litter mass loss and plant growth response to elevated atmospheric CO2 using two wetland plants: a C3 sedge (Scirpus olneyi) and a C4 grass (Spartina patens). Our field study revealed that organism's sensitivity to climate increased with trophic level resulting in strong inter-annual variation in detritus-based food chain length. Our microcosm experiment demonstrated that increased detritivore abundance could not only enhance decomposition rates, but also enhance plant growth of S. olneyi in elevated atmospheric CO2 conditions. In contrast, we found no evidence that changes in the detritus-based food chains influenced the growth of S. patens. Considered together, these results emphasize the importance of approaches that unite traditionally subdivided food web compartments and plant physiological processes to understand inter-annual variation in plant production response to elevated atmospheric CO2. © 2015 John Wiley & Sons Ltd.

Nutritional Aspects of Bone Health and Fracture Healing

PubMed Central

Karpouzos, Athanasios; Diamantis, Evangelos; Farmaki, Paraskevi

2017-01-01

Introduction Fractures are quite common, especially among the elderly. However, they can increase in prevalence in younger ages too if the bone health is not good. This may happen as a result of bad nutrition. Methods A customized, retrospective review of available literature was performed using the following keywords: bone health, nutrition, and fractures. Results Insufficient intake of certain vitamins, particularly A and D, and other nutrients, such as calcium, may affect bone health or even the time and degree of bone healing in case of fracture. The importance of different nutrients, both dietary and found in food supplements, is discussed concerning bone health and fracture healing. Conclusion A healthy diet with adequate amounts of both macro- and micronutrients is essential, for both decreasing fracture risk and enhancing the healing process after fracture. PMID:29464131

Soy-enhanced lunch acceptance by preschoolers.

PubMed

Endres, Jeannette; Barter, Sharon; Theodora, Perseli; Welch, Patricia

2003-03-01

To evaluate acceptance of soy-enhanced compared with traditional menus by preschool children. Soy-enhanced foods were substituted on a traditional cycle menu, and the amount eaten, energy, and nutrient values for traditional and soy-enhanced lunches were compared. A traditional three-week cycle menu, using the Child and Adult Care Food Program (CACFP) meal pattern guidelines, was used to develop a comparable soy-enhanced menu. Traditional and soy-enhanced lunches were randomly assigned to respective days. Foods were portioned onto individual plates using standardized measuring utensils. Individual plate waste techniques were used to collect food waste. Subjects/setting Participants were preschool children, three to six years of age and of white and Hispanic origin, attending a part-day Head Start program. Statistical analyses performed Analysis of covariance was used to adjust lunch and food intakes for differences in average amounts of foods served. The Nutrient Data System was used to calculate energy and nutrient content of lunches. Analysis of variance was used to calculate differences in amounts eaten, energy values, and nutrient values of traditional and soy-enhanced lunches and foods. Data analyses were performed with the Statistical Analysis Software (version 8.0, 1999, SAS Institute, Cary, NC). Soy-enhanced foods were successfully substituted for 23 traditional foods included in the cycle menus. Soy-enhanced foods tended to be higher in energy, protein, and iron. Traditional lunches tended to be higher in fat, saturated fat, and vitamin A. Consumption was significantly less for energy, protein, fiber, and iron from foods eaten from traditional compared with soy-enhanced lunch menus. Applications/conclusions Acceptance of soy-enhanced lunches was shown because there were no significant differences in the average amount eaten (grams per meal) between traditional and soy-enhanced lunches. Preschool programs can substitute soy-enhanced for traditional foods, which will add variety to the diet without sacrificing taste, energy, or nutrient value. The fat and energy content of the lunches was higher than recommended, and soy-enhanced foods were not always lower in fat. There is a need for the food industry and foodservice personnel to address the energy and fat content of all foods served in lunches to preschool children because a few extra calories added to the daily intakes can contribute to weight gain.

Reconstruction of surface water conditions in the central region of the Okhotsk Sea during the last 180 kyrs

NASA Astrophysics Data System (ADS)

Khim, Boo-Keun; Sakamoto, Tatsuhiko; Harada, Naomi

2012-02-01

Core GC9A, a 6.7 m long gravity core collected from the central region of the Okhotsk Sea during Cruise YK0712 on R/V Yokosuka (JAMSTEC), was used to reconstruct the changes in surface water conditions by measuring biogenic components (biogenic opal, CaCO3, total organic carbon and δ15N of sediment organic matter) of sediment samples. The age of Core GC9A was determined indirectly by graphic correlation comparing the b* (psychometric yellow-blue chromaticness) values with those of well-dated Core MD01-2415, with complement to the tephra layer (K3; 50 ka). The bottom age of Core GC9A was estimated to be about 180 kyr; therefore it provides the history of surface water conditions from MIS 1 to MIS 6. The biogenic opal, CaCO3, and TOC contents were high during the interglacial periods as expected, indicating enhanced surface water production under warm climatic conditions. This condition resulted from sufficient nutrient supply to the surface waters by active vertical mixing, which was validated by low δ15N values of the sediment organic matter. In contrast, surface water productivity was depressed during the colder glacial periods, probably due to the expanded sea-ice distribution and limited nutrient supply. However, the glacial sediments had moderately high δ15N values, indicating enhanced nitrate utilization resulting from the limited nutrient supply caused by strong stratification of the surface water. High δ15N values were also observed during the deglaciation, which was attributed to the increased nitrate utilization during enhanced surface water productivity. However, the low δ15N values during the glacial and deglacial periods may be attributed to the increased supply of terrestrial organic matter. Diatom production was primarily responsible for surface water paleoproductivity during the interglacial periods rather than coccolithophores. However, the succession of glacial to early deglacial coccolithophore production and late deglacial to interglacial diatom production was remarkable, corresponding to the present-day seasonal phytoplankton succession. Such an advanced coccolithophore production relative to diatom production might be attributed to the degree of nutrient availability associated with surface water conditions on the basis of variations in the δ15N value. Finally, the opal and TOC contents decreased abruptly in conjunction with a gradual decrease in CaCO3 content from about 2 ka, which seems to implicate a late Holocene sudden decrease in paleoproductivity in the central region of the Okhotsk Sea. According to the increase in δ15N values during this interval, nutrient availability appears to be poor, which is likely attributed to the resumed strong stratification that occurred due to the southward shift of the Aleutian Low atmospheric pressure system.

Strategy of nitrogen acquisition and utilization by carnivorous Dionaea muscipula.

PubMed

Kruse, Jörg; Gao, Peng; Honsel, Anne; Kreuzwieser, Jürgen; Burzlaff, Tim; Alfarraj, Saleh; Hedrich, Rainer; Rennenberg, Heinz

2014-03-01

Plant carnivory represents an exceptional means to acquire N. Snap traps of Dionaea muscipula serve two functions, and provide both N and photosynthate. Using (13)C/(15)N-labelled insect powder, we performed feeding experiments with Dionaea plants that differed in physiological state and N status (spring vs. autumn plants). We measured the effects of (15)N uptake on light-saturated photosynthesis (A(max)), dark respiration (R(D)) and growth. Depending on N status, insect capture briefly altered the dynamics of R(D)/A(max), reflecting high energy demand during insect digestion and nutrient uptake, followed by enhanced photosynthesis and growth. Organic N acquired from insect prey was immediately redistributed, in order to support swift renewal of traps and thereby enhance probability of prey capture. Respiratory costs associated with permanent maintenance of the photosynthetic machinery were thereby minimized. Dionaea's strategy of N utilization is commensurate with the random capture of large prey, occasionally transferring a high load of organic nutrients to the plant. Our results suggest that physiological adaptations to unpredictable resource availability are essential for Dionaea's success with regards to a carnivorous life style.

Insect-based protein: future promising protein source for fish cultured

NASA Astrophysics Data System (ADS)

Nugroho, R. A.; Nur, F. M.

2018-04-01

As one of the vital component feed used in fisheries, fishmeal (FM) is generally added to the fish diet to enhance fish growth, digestive performance and absorption of nutrients. This addition contributes significantly to the variable production cost in the aquaculture industry. Expanded production of carnivorous species requiring high protein, high-energy feeds will further tax global fish meal. Thus, research based on the low-cost budget for feed operating cost should be strategized to assist aquaculturists in enhancing fish productivity. Moreover, suitable alternative feed ingredients will have to be utilized to provide the essential nutrients and energy needed to fuel the growth of aquaculture production. To this effect, the use of insect-based protein sources to replace FM that often scarce, expensive, limited availability, and leads to high fish production costs is alternative ways and has been gaining momentum. Currently, Insects have been proposed as one of the potential future protein sources of protein because of the production of insects is highly sustainable. Farming insects is characterized by higher food conversion efficiencies, lower environmental impact, and higher potential to be grown on waste streams.

Combating Human Micronutrient Deficiencies through Soil Management Practices that Enhance Bioavailability of Nutrients to Plants

ERIC Educational Resources Information Center

O'Meara, Mary

2009-01-01

Micronutrient malnutrition affects the health and well being of 3 billion people globally. Identifying means to improve the micronutrient density in the edible portions of crops is an important way to combat nutrient deficiencies. By studying how plants obtain micronutrients from the soil, we can develop methods to enhance uptake. Although more…

Impacts of light shading and nutrient enrichment geo-engineering approaches on the productivity of a stratified, oligotrophic ocean ecosystem.

PubMed

Hardman-Mountford, Nick J; Polimene, Luca; Hirata, Takafumi; Brewin, Robert J W; Aiken, Jim

2013-12-06

Geo-engineering proposals to mitigate global warming have focused either on methods of carbon dioxide removal, particularly nutrient fertilization of plant growth, or on cooling the Earth's surface by reducing incoming solar radiation (shading). Marine phytoplankton contribute half the Earth's biological carbon fixation and carbon export in the ocean is modulated by the actions of microbes and grazing communities in recycling nutrients. Both nutrients and light are essential for photosynthesis, so understanding the relative influence of both these geo-engineering approaches on ocean ecosystem production and processes is critical to the evaluation of their effectiveness. In this paper, we investigate the relationship between light and nutrient availability on productivity in a stratified, oligotrophic subtropical ocean ecosystem using a one-dimensional water column model coupled to a multi-plankton ecosystem model, with the goal of elucidating potential impacts of these geo-engineering approaches on ecosystem production. We find that solar shading approaches can redistribute productivity in the water column but do not change total production. Macronutrient enrichment is able to enhance the export of carbon, although heterotrophic recycling reduces the efficiency of carbon export substantially over time. Our results highlight the requirement for a fuller consideration of marine ecosystem interactions and feedbacks, beyond simply the stimulation of surface blooms, in the evaluation of putative geo-engineering approaches.

Impacts of light shading and nutrient enrichment geo-engineering approaches on the productivity of a stratified, oligotrophic ocean ecosystem

PubMed Central

Hardman-Mountford, Nick J.; Polimene, Luca; Hirata, Takafumi; Brewin, Robert J. W.; Aiken, Jim

2013-01-01

Geo-engineering proposals to mitigate global warming have focused either on methods of carbon dioxide removal, particularly nutrient fertilization of plant growth, or on cooling the Earth's surface by reducing incoming solar radiation (shading). Marine phytoplankton contribute half the Earth's biological carbon fixation and carbon export in the ocean is modulated by the actions of microbes and grazing communities in recycling nutrients. Both nutrients and light are essential for photosynthesis, so understanding the relative influence of both these geo-engineering approaches on ocean ecosystem production and processes is critical to the evaluation of their effectiveness. In this paper, we investigate the relationship between light and nutrient availability on productivity in a stratified, oligotrophic subtropical ocean ecosystem using a one-dimensional water column model coupled to a multi-plankton ecosystem model, with the goal of elucidating potential impacts of these geo-engineering approaches on ecosystem production. We find that solar shading approaches can redistribute productivity in the water column but do not change total production. Macronutrient enrichment is able to enhance the export of carbon, although heterotrophic recycling reduces the efficiency of carbon export substantially over time. Our results highlight the requirement for a fuller consideration of marine ecosystem interactions and feedbacks, beyond simply the stimulation of surface blooms, in the evaluation of putative geo-engineering approaches. PMID:24132201

ADDING NUTRIENTS TO ENHANCE SALMON RUNS: DEVELOPING A COHERENT PUBLIC POLICY

EPA Science Inventory

One scheme to help restore salmon to the Pacific Northwest is the addition of nutrients (i.e., raw or processed salmon carcasses, and commercially produced organic or inorganic fertilizers) to headwaters (i.e., watersheds, lakes, or streams) that are now nutrient deficient becau...

Effect of enhanced homestead food production and aquaculture on dietary intakes of women and children in rural Cambodia: A cluster randomized controlled trial.

PubMed

Verbowski, Vashti; Talukder, Zaman; Hou, Kroeun; Sok Hoing, Ly; Michaux, Kristina; Anderson, Victoria; Gibson, Rosalind; Li, Kathy H; Lynd, Larry D; McLean, Judy; Green, Tim J; Barr, Susan I

2018-01-05

The Cambodian diet is low in nutrient-dense animal-source foods. Enhanced homestead food production (EHFP) and aquaculture, which increase availability of nutrient-dense foods, are promising interventions to improve dietary intake. This study examined the effect of EHFP with or without aquaculture on dietary intake and prevalence of inadequate intake of select nutrients among women and children living in rural Cambodia, compared to controls. In a registered, cluster randomized controlled trial in Prey Veng, Cambodia, 10 households in each of 90 villages (n = 900) were randomized by village to receive EHFP, EHFP plus aquaculture, or control. After 22-month intervention, 24-hr dietary recalls (24HRs) were collected from mothers aged 18-50 years (n = 429) and their children aged 6 months-7 years (n = 421), reported by their mothers. Usual intake distributions (generated using 24HRs and repeat 24HRs on a subsample) were used to estimate prevalence of inadequate intake. Compared to controls, women in the EHFP group had significantly higher zinc (+1.0 mg/d) and Vitamin A (+139 retinol activity equivalents/d) intakes, and women in the EHFP plus aquaculture group had significantly higher iron (+2.7 mg/d), Vitamin A (+191 retinol activity equivalents/d), and riboflavin (+0.17 mg/d) intakes. Women in the EHFP plus aquaculture group also had significantly lower prevalence of inadequate iron (-7%, at 10% bioavailability), Vitamin A (-19%), and riboflavin (-17%) intakes, compared to controls. No significant differences in intakes or nutrient adequacy were observed among children or between EHFP and EHFP plus aquaculture groups. The biological importance of the small differences in nutrient intakes among women remains to be established. © 2018 John Wiley & Sons Ltd.

Responses of nutrient capture and fine root morphology of subalpine coniferous tree Picea asperata to nutrient heterogeneity and competition

PubMed Central

Nan, Hongwei; Liang, Jin; Cheng, Xinying; Zhao, ChunZhang; Yin, HuaJun; Yin, ChunYing; Liu, Qing

2017-01-01

Investigating the responses of trees to the heterogeneous distribution of nutrients in soil and simultaneous presence of neighboring roots could strengthen the understanding of an influential mechanism on tree growth and provide a scientific basis for forest management. Here, we conducted two split-pot experiments to investigate the effects of nutrient heterogeneity and intraspecific competition on the fine root morphology and nutrient capture of Picea asperata. The results showed that P. asperata efficiently captured nutrients by increasing the specific root length (SRL) and specific root area (SRA) of first-and second-order roots and decreasing the tissue density of first-order roots to avoid competition for resources and space with neighboring roots. The nutrient heterogeneity and addition of fertilization did not affect the fine root morphology, but enhanced the P and K concentrations in the fine roots in the absence of a competitor. On the interaction between nutrient heterogeneity and competition, competition decreased the SRL and SRA but enhanced the capture of K under heterogeneous soil compared with under homogeneous soil. Additionally, the P concentration, but not the K concentration, was linearly correlated to root morphology in heterogeneous soil, even when competition was present. The results suggested that root morphological features were only stimulated when the soil nutrients were insufficient for plant growth and the nutrients accumulations by root were mainly affected by the soil nutrients more than the root morphology. PMID:29095947

A novel approach to enhance biological nutrient removal using a culture supernatant from Micrococcus luteus containing resuscitation-promoting factor (Rpf) in SBR process.

PubMed

Liu, Yindong; Su, Xiaomei; Lu, Lian; Ding, Linxian; Shen, Chaofeng

2016-03-01

A culture supernatant from Micrococcus luteus containing resuscitation-promoting factor (SRpf) was used to enhance the biological nutrient removal of potentially functional bacteria. The obtained results suggest that SRpf accelerated the start-up process and significantly enhanced the biological nutrient removal in sequencing batch reactor (SBR). PO4 (3-)-P removal efficiency increased by over 12 % and total nitrogen removal efficiency increased by over 8 % in treatment reactor acclimated by SRpf compared with those without SRpf addition. The Illumina high-throughput sequencing analysis showed that SRpf played an essential role in shifts in the composition and diversity of bacterial community. The phyla of Proteobacteria and Actinobacteria, which were closely related to biological nutrient removal, were greatly abundant after SRpf addition. This study demonstrates that SRpf acclimation or addition might hold great potential as an efficient and cost-effective alternative for wastewater treatment plants (WWTPs) to meet more stringent operation conditions and legislations.

Wastewater treatment to enhance the economic viability of microalgae culture.

PubMed

Pires, J C M; Alvim-Ferraz, M C M; Martins, F G; Simões, M

2013-08-01

Microalgae culture is still not economically viable and it presents some negative environmental impacts, concerning water, nutrient and energy requirements. In this context, this study aims to review the recent advances on microalgal cultures in wastewaters to enhance their economic viability. We focused on three different culture concepts: (1) suspended cell systems, (2) cell immobilization, and (3) microalgae consortia. Cultures with suspended cells are the most studied. The nutrient removal efficiencies are usually high for wastewaters of different sources. However, biomass harvesting is difficult and a costly process due to the small cell size and lower culture density. On the other hand, the cell immobilization systems showed to be the solution for this problem, having as main limitation the nutrient diffusion from bulk to cells, which results in a reduced nutrient removal efficiency. The consortium between microalgae and bacteria enhances the growth of both microorganisms. This culture concept showed to be a promising technology to improve wastewater treatment, regarding not only nutrient removal but also biomass harvesting by bioflocculation. The aggregation mechanism must be studied in depth to find the process parameters that would lead to an effective and cheap harvesting process.

Response of plant nutrient stoichiometry to fertilization varied with plant tissues in a tropical forest

PubMed Central

Mo, Qifeng; Zou, Bi; Li, Yingwen; Chen, Yao; Zhang, Weixin; Mao, Rong; Ding, Yongzhen; Wang, Jun; Lu, Xiankai; Li, Xiaobo; Tang, Jianwu; Li, Zhian; Wang, Faming

2015-01-01

Plant N:P ratios are widely used as indices of nutrient limitation in terrestrial ecosystems, but the response of these metrics in different plant tissues to altered N and P availability and their interactions remains largely unclear. We evaluated changes in N and P concentrations, N:P ratios of new leaves (<1 yr), older leaves (>1 yr), stems and mixed fine roots of seven species after 3-years of an N and P addition experiment in a tropical forest. Nitrogen addition only increased fine root N concentrations. P addition increased P concentrations among all tissues. The N × P interaction reduced leaf and stem P concentrations, suggesting a negative effect of N addition on P concentrations under P addition. The reliability of using nutrient ratios as indices of soil nutrient availability varied with tissues: the stoichiometric metrics of stems and older leaves were more responsive indicators of changed soil nutrient availability than those of new leaves and fine roots. However, leaf N:P ratios can be a useful indicator of inter-specific variation in plant response to nutrients availability. This study suggests that older leaf is a better choice than other tissues in the assessment of soil nutrient status and predicting plant response to altered nutrients using nutrients ratios. PMID:26416169

Evaluating Aquatic Life Benefits of Reducing Nutrient Loading to Remediate Episodic and Diel Cycling Hypoxia in a Shallow Hypereutrophic Estuary

EPA Science Inventory

Theoretical linkages between excess nutrient loading, nutrient-enhanced community metabolism (i.e., production and respiration), and hypoxia in estuaries are well-understood. In seasonally-stratified estuaries and coastal systems (e.g., Chesapeake Bay, northern Gulf of Mexico), h...

Root traits explain observed tundra vegetation nitrogen uptake patterns: Implications for trait-based land models: Tundra N Uptake Model-Data Comparison

DOE PAGES

Zhu, Qing; Iversen, Colleen M.; Riley, William J.; ...

2016-12-23

Ongoing climate warming will likely perturb vertical distributions of nitrogen availability in tundra soils through enhancing nitrogen mineralization and releasing previously inaccessible nitrogen from frozen permafrost soil. But, arctic tundra responses to such changes are uncertain, because of a lack of vertically explicit nitrogen tracer experiments and untested hypotheses of root nitrogen uptake under the stress of microbial competition implemented in land models. We conducted a vertically explicit 15N tracer experiment for three dominant tundra species to quantify plant N uptake profiles. Then we applied a nutrient competition model (N-COM), which is being integrated into the ACME Land Model, tomore » explain the observations. Observations using an 15N tracer showed that plant N uptake profiles were not consistently related to root biomass density profiles, which challenges the prevailing hypothesis that root density always exerts first-order control on N uptake. By considering essential root traits (e.g., biomass distribution and nutrient uptake kinetics) with an appropriate plant-microbe nutrient competition framework, our model reasonably reproduced the observed patterns of plant N uptake. Additionally, we show that previously applied nutrient competition hypotheses in Earth System Land Models fail to explain the diverse plant N uptake profiles we observed. These results cast doubt on current climate-scale model predictions of arctic plant responses to elevated nitrogen supply under a changing climate and highlight the importance of considering essential root traits in large-scale land models. Finally, we provided suggestions and a short synthesis of data availability for future trait-based land model development.« less

Distinct Microbial Limitations in Litter and Underlying Soil Revealed by Carbon and Nutrient Fertilization in a Tropical Rainforest

PubMed Central

Fanin, Nicolas; Barantal, Sandra; Fromin, Nathalie; Schimann, Heidy; Schevin, Patrick; Hättenschwiler, Stephan

2012-01-01

Human-caused alterations of the carbon and nutrient cycles are expected to impact tropical ecosystems in the near future. Here we evaluated how a combined change in carbon (C), nitrogen (N) and phosphorus (P) availability affects soil and litter microbial respiration and litter decomposition in an undisturbed Amazonian rainforest in French Guiana. In a fully factorial C (as cellulose), N (as urea), and P (as phosphate) fertilization experiment we analyzed a total of 540 litterbag-soil pairs after a 158-day exposure in the field. Rates of substrate-induced respiration (SIR) measured in litter and litter mass loss were similarly affected by fertilization showing the strongest stimulation when N and P were added simultaneously. The stimulating NP effect on litter SIR increased considerably with increasing initial dissolved organic carbon (DOC) concentrations in litter, suggesting that the combined availability of N, P, and a labile C source has a particularly strong effect on microbial activity. Cellulose fertilization, however, did not further stimulate the NP effect. In contrast to litter SIR and litter mass loss, soil SIR was reduced with N fertilization and showed only a positive effect in response to P fertilization that was further enhanced with additional C fertilization. Our data suggest that increased nutrient enrichment in the studied Amazonian rainforest can considerably change microbial activity and litter decomposition, and that these effects differ between the litter layer and the underlying soil. Any resulting change in relative C and nutrient fluxes between the litter layer and the soil can have important consequences for biogeochemical cycles in tropical forest ecosystems. PMID:23272052

Root traits explain observed tundra vegetation nitrogen uptake patterns: Implications for trait-based land models: Tundra N Uptake Model-Data Comparison

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Qing; Iversen, Colleen M.; Riley, William J.

Ongoing climate warming will likely perturb vertical distributions of nitrogen availability in tundra soils through enhancing nitrogen mineralization and releasing previously inaccessible nitrogen from frozen permafrost soil. But, arctic tundra responses to such changes are uncertain, because of a lack of vertically explicit nitrogen tracer experiments and untested hypotheses of root nitrogen uptake under the stress of microbial competition implemented in land models. We conducted a vertically explicit 15N tracer experiment for three dominant tundra species to quantify plant N uptake profiles. Then we applied a nutrient competition model (N-COM), which is being integrated into the ACME Land Model, tomore » explain the observations. Observations using an 15N tracer showed that plant N uptake profiles were not consistently related to root biomass density profiles, which challenges the prevailing hypothesis that root density always exerts first-order control on N uptake. By considering essential root traits (e.g., biomass distribution and nutrient uptake kinetics) with an appropriate plant-microbe nutrient competition framework, our model reasonably reproduced the observed patterns of plant N uptake. Additionally, we show that previously applied nutrient competition hypotheses in Earth System Land Models fail to explain the diverse plant N uptake profiles we observed. These results cast doubt on current climate-scale model predictions of arctic plant responses to elevated nitrogen supply under a changing climate and highlight the importance of considering essential root traits in large-scale land models. Finally, we provided suggestions and a short synthesis of data availability for future trait-based land model development.« less

Rhizosphere effect on phosphorus availability in forest soils at different altitudes.

NASA Astrophysics Data System (ADS)

De Feudis, Mauro; Cardelli, Valeria; Massaccesi, Luisa; Bol, Roland; Willbold, Sabine; Cocco, Stefania; Corti, Giuseppe; Agnelli, Alberto

2016-04-01

Phosphorus (P) is an essential nutrient for plants but it is one of the least available mineral nutrients, and can substantially limit plant growth. Although plants are able to respond to the P shortage, the global warming might modify the soil-plant-microorganisms system and reduce P availability. We evaluated the rhizosphere effect of beech (Fagus sylvatica L.) in forest soils of the Apennines mountains (central Italy) at two altitudes (800 and 1000 m) and along 1° of latitudinal gradient, using latitude and altitude as proxies for temperature change. Specifically, we tested if 1) soil organic C, total N, and organic and available P decrease with increasing latitude and altitude, and 2) the rhizosphere effect on P availability becomes more pronounced when potential nutrient limitations are more severe, as it happens with increasing latitude and altitude. The results suggested that the small latitudinal gradient has no effect on soil properties. Conversely, significant changes occurred between 800 and 1000 m a.s.l., as the soils at higher altitude showed greater TOC, organic and available P contents, and alkaline mono-phosphatases activity than the soils at 800 m a.s.l. Compared to the soils at lower altitude, a marked rhizosphere effect was found at 1000 m a.s.l., and it was mainly attributed to the release of labile organics through rhizodeposition processes. These labile organic compounds were considered able to induce a "priming effect" that fostered the mineralization of the soil organic matter. The enhanced organic carbon cycling, in turn, likely promoted the mineralization of the organic P forms. This was supported by the smaller proportion of orthophosphate monoesters found in the P pool of the rhizosphere than in that of the soil far from the roots, with a consequent increase of the amount of available P. Hence, we speculate that at high altitude the energy supplied by the plants through rhizodeposition to the rhizosphere heterotrophic microbial community promotes the rhizospheric biochemical processes and, in particular, P cycling.

Effects of harvesting on nitrogen and phosphorus availability in riparian management zone soils in Minnesota, USA

Treesearch

Douglas N. Kastendick; Eric K. Zenner; Brian J. Palik; Randall K. Kolka; Charles R. Blinn

2012-01-01

Riparian management zones (RMZs) protect streams from excess nutrients, yet few studies have looked at soil nutrients in forested RMZs or the impacts of partial harvesting on nutrient availability. We investigated the impacts of upland clearcutting in conjunction with uncut and partially harvested RMZs (40% basal area reduction) on soil nutrients in forests in...

Small-scale drivers: the importance of nutrient availability and snowmelt timing on performance of the alpine shrub Salix herbacea.

PubMed

Little, Chelsea J; Wheeler, Julia A; Sedlacek, Janosch; Cortés, Andrés J; Rixen, Christian

2016-04-01

Alpine plant communities are predicted to face range shifts and possibly extinctions with climate change. Fine-scale environmental variation such as nutrient availability or snowmelt timing may contribute to the ability of plant species to persist locally; however, variation in nutrient availability in alpine landscapes is largely unmeasured. On three mountains around Davos, Switzerland, we deployed Plant Root Simulator probes around 58 Salix herbacea plants along an elevational and microhabitat gradient to measure nutrient availability during the first 5 weeks of the summer growing season, and used in situ temperature loggers and observational data to determine date of spring snowmelt. We also visited the plants weekly to assess performance, as measured by stem number, fruiting, and herbivory damage. We found a wide snowmelt gradient which determined growing season length, as well as variations of an order of magnitude or more in the accumulation of 12 nutrients between different microhabitats. Higher nutrient availability had negative effects on most shrub performance metrics, for instance decreasing stem number and the proportion of stems producing fruits. High nutrient availability was associated with increased herbivory damage in early-melting microhabitats, but among late-emerging plants this pattern was reversed. We demonstrate that nutrient availability is highly variable in alpine settings, and that it strongly influences performance in an alpine dwarf shrub, sometimes modifying the response of shrubs to snowmelt timing. As the climate warms and human-induced nitrogen deposition continues in the Alps, these factors may contribute to patterns of local plants persistence.

Available nutrients in biochar

USDA-ARS?s Scientific Manuscript database

Biochar technology may contribute to the recovery and recycling of plant nutrients and thus add a fertilizer value to the biochar. Total nutrient content in biochars varies greatly and is mainly dependent on feedstock elemental composition and to a lesser extent on pyrolysis conditions. Availability...

Glycogen Synthase Kinase-3 and Mammalian Target of Rapamycin Pathways Contribute to DNA Synthesis, Cell Cycle Progression, and Proliferation in Human Islets

PubMed Central

Liu, Hui; Remedi, Maria S.; Pappan, Kirk L.; Kwon, Guim; Rohatgi, Nidhi; Marshall, Connie A.; McDaniel, Michael L.

2009-01-01

OBJECTIVE—Our previous studies demonstrated that nutrient regulation of mammalian target of rapamycin (mTOR) signaling promotes regenerative processes in rodent islets but rarely in human islets. Our objective was to extend these findings by using therapeutic agents to determine whether the regulation of glycogen synthase kinase-3 (GSK-3)/β-catenin and mTOR signaling represent key components necessary for effecting a positive impact on human β-cell mass relevant to type 1 and 2 diabetes. RESEARCH DESIGN AND METHODS—Primary adult human and rat islets were treated with the GSK-3 inhibitors, LiCl and the highly potent 1-azakenpaullone (1-Akp), and with nutrients. DNA synthesis, cell cycle progression, and proliferation of β-cells were assessed. Measurement of insulin secretion and content and Western blot analysis of GSK-3 and mTOR signaling components were performed. RESULTS—Human islets treated for 4 days with LiCl or 1-Akp exhibited significant increases in DNA synthesis, cell cycle progression, and proliferation of β-cells that displayed varying degrees of sensitivity to rapamycin. Intermediate glucose (8 mmol/l) produced a striking degree of synergism in combination with GSK-3 inhibition to enhance bromodeoxyuridine (BrdU) incorporation and Ki-67 expression in human β-cells. Nuclear translocation of β-catenin responsible for cell proliferation was found to be particularly sensitive to rapamycin. CONCLUSIONS—A combination of GSK-3 inhibition and nutrient activation of mTOR contributes to enhanced DNA synthesis, cell cycle progression, and proliferation of human β-cells. Identification of therapeutic agents that appropriately regulate GSK-3 and mTOR signaling may provide a feasible and available approach to enhance human islet growth and proliferation. PMID:19073772

Foxtail Millet [Setaria italica (L.) Beauv.] Grown under Low Nitrogen Shows a Smaller Root System, Enhanced Biomass Accumulation, and Nitrate Transporter Expression.

PubMed

Nadeem, Faisal; Ahmad, Zeeshan; Wang, Ruifeng; Han, Jienan; Shen, Qi; Chang, Feiran; Diao, Xianmin; Zhang, Fusuo; Li, Xuexian

2018-01-01

Foxtail millet (FM) [ Setaria italica (L.) Beauv.] is a grain and forage crop well adapted to nutrient-poor soils. To date little is known how FM adapts to low nitrogen (LN) at the morphological, physiological, and molecular levels. Using the FM variety Yugu1, we found that LN led to lower chlorophyll contents and N concentrations, and higher root/shoot and C/N ratios and N utilization efficiencies under hydroponic culture. Importantly, enhanced biomass accumulation in the root under LN was in contrast to a smaller root system, as indicated by significant decreases in total root length; crown root number and length; and lateral root number, length, and density. Enhanced carbon allocation toward the root was rather for significant increases in average diameter of the LN root, potentially favorable for wider xylem vessels or other anatomical alterations facilitating nutrient transport. Lower levels of IAA and CKs were consistent with a smaller root system and higher levels of GA may promote root thickening under LN. Further, up-regulation of SiNRT1.1, SiNRT2.1, and SiNAR2.1 expression and nitrate influx in the root and that of SiNRT1.11 and SiNRT1.12 expression in the shoot probably favored nitrate uptake and remobilization as a whole. Lastly, more soluble proteins accumulated in the N-deficient root likely as a result of increases of N utilization efficiencies. Such "excessive" protein-N was possibly available for shoot delivery. Thus, FM may preferentially transport carbon toward the root facilitating root thickening/nutrient transport and allocate N toward the shoot maximizing photosynthesis/carbon fixation as a primary adaptive strategy to N limitation.

Contribution of Golden Apple Snail Flour to Enhance Omega- 3 and Omega-6 Fatty Acids Contents in Weaning Food

NASA Astrophysics Data System (ADS)

Marsyha, D. D.; Wijayanti, H. S.; Nuryanto; Anjani, G.

2018-02-01

The case of undernourished children in Grobogan District (15.3%) is caused by children nutrients intake less than the Recommendation Dietary Allowance (RDA). To enhance children nutrients intake, be required formulation of weaning food using high-nutrient local food such as golden apple snail (Pomacea canaliculata). Golden apple snail flour contains high contents of zinc, iron, omega-3 and omega-6 fatty acids. This study aims to analyze the effect of golden apple snail flour substitution on nutrients content and organoleptic properties of weaning food (baby porridge). This is an experimental research by substitution of golden apple snail flour in the making of weaning food with four treatments of substitution (0%, 5%, 10%, 15%). Substitution of golden apple snails flour could affect the nutrient content levels of fat, zinc, iron (p=0.0001), carbohydrate (p=0.011), water (p=0.003), ash (p=0.001), omega-3 and omega-6 fatty acids. Whereas, it could not affect the content of energy (p=0.678), protein (p=0.129) and fiber (p=0.482). Furthermore, the substitution could affect the organoleptic properties include color, texture and taste (p=0.0001) while not for the aroma (p=0.798). Based on nutrient content analysis, substitution of golden apple snail flour could enhance the zinc, iron, omega-3 and omega-6 fatty acids contents of weaning food.

Role of model structure on the response of soil biogeochemistry to hydro-climatic fluctuations

NASA Astrophysics Data System (ADS)

Manzoni, S.; Porporato, A.

2005-05-01

Soil carbon and nutrient cycles are strongly affected by hydro-climatic variability, which interacts with the internal ecosystem structure. Here we test the implications of biogeochemical model structure on such dynamics by extending an existing model by the authors and coworkers. When forced by hydro-climatic fluctuations, the different model structures induce specific preferential nutrient paths among the soil pools, which in turn affect nutrient distribution and availability to microbes and plants. In particular, if it is assumed that microbes can directly assimilate organic nitrogen, plants tend to be inferior competitors for nutrients even in well-watered conditions, while if a certain amount of organic nitrogen is assumed to be mineralized without being first incorporated into microbial cells, vegetation can be advantaged over a wide range of soil moisture values. We also investigate the intensification of competition for nutrients (e.g., nitrogen) between plant and soil microbial communities under extreme hydrologic conditions, such as droughts and intense storms. Frequent rainfall events may determine ideal soil moisture conditions for plant uptake, enhancing nitrogen leaching while lowering oxygen concentration and inhibiting microbial activity. During droughts, the soil water potential often drops to the point of hampering the plant nutrient uptake while still remaining high enough for microbial decomposition and nitrogen immobilization. The interplay of microbe and vegetation water stress is investigated in depth as it controls the ability of one community (e.g., plants or soil microbes) to establish competitive advantage on the other. The long-term effects of these dynamics of competition and nutrient allocation are explored under steady-state and stochastic soil moisture conditions to analyze the feedbacks between soil organic matter and vegetation dynamics.

Symbiotic soil fungi enhance ecosystem resilience to climate change.

PubMed

Martínez-García, Laura B; De Deyn, Gerlinde B; Pugnaire, Francisco I; Kothamasi, David; van der Heijden, Marcel G A

2017-12-01

Substantial amounts of nutrients are lost from soils through leaching. These losses can be environmentally damaging, causing groundwater eutrophication and also comprise an economic burden in terms of lost agricultural production. More intense precipitation events caused by climate change will likely aggravate this problem. So far it is unresolved to which extent soil biota can make ecosystems more resilient to climate change and reduce nutrient leaching losses when rainfall intensity increases. In this study, we focused on arbuscular mycorrhizal (AM) fungi, common soil fungi that form symbiotic associations with most land plants and which increase plant nutrient uptake. We hypothesized that AM fungi mitigate nutrient losses following intensive precipitation events (higher amount of precipitation and rain events frequency). To test this, we manipulated the presence of AM fungi in model grassland communities subjected to two rainfall scenarios: moderate and high rainfall intensity. The total amount of nutrients lost through leaching increased substantially with higher rainfall intensity. The presence of AM fungi reduced phosphorus losses by 50% under both rainfall scenarios and nitrogen losses by 40% under high rainfall intensity. Thus, the presence of AM fungi enhanced the nutrient interception ability of soils, and AM fungi reduced the nutrient leaching risk when rainfall intensity increases. These findings are especially relevant in areas with high rainfall intensity (e.g., such as the tropics) and for ecosystems that will experience increased rainfall due to climate change. Overall, this work demonstrates that soil biota such as AM fungi can enhance ecosystem resilience and reduce the negative impact of increased precipitation on nutrient losses. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Experimentally increased nutrient availability at the permafrost thaw front selectively enhances biomass production of deep-rooting subarctic peatland species.

PubMed

Keuper, Frida; Dorrepaal, Ellen; van Bodegom, Peter M; van Logtestijn, Richard; Venhuizen, Gemma; van Hal, Jurgen; Aerts, Rien

2017-10-01

Climate warming increases nitrogen (N) mineralization in superficial soil layers (the dominant rooting zone) of subarctic peatlands. Thawing and subsequent mineralization of permafrost increases plant-available N around the thaw-front. Because plant production in these peatlands is N-limited, such changes may substantially affect net primary production and species composition. We aimed to identify the potential impact of increased N-availability due to permafrost thawing on subarctic peatland plant production and species performance, relative to the impact of increased N-availability in superficial organic layers. Therefore, we investigated whether plant roots are present at the thaw-front (45 cm depth) and whether N-uptake ( 15 N-tracer) at the thaw-front occurs during maximum thaw-depth, coinciding with the end of the growing season. Moreover, we performed a unique 3-year belowground fertilization experiment with fully factorial combinations of deep- (thaw-front) and shallow-fertilization (10 cm depth) and controls. We found that certain species are present with roots at the thaw-front (Rubus chamaemorus) and have the capacity (R. chamaemorus, Eriophorum vaginatum) for N-uptake from the thaw-front between autumn and spring when aboveground tissue is largely senescent. In response to 3-year shallow-belowground fertilization (S) both shallow- (Empetrum hermaphroditum) and deep-rooting species increased aboveground biomass and N-content, but only deep-rooting species responded positively to enhanced nutrient supply at the thaw-front (D). Moreover, the effects of shallow-fertilization and thaw-front fertilization on aboveground biomass production of the deep-rooting species were similar in magnitude (S: 71%; D: 111% increase compared to control) and additive (S + D: 181% increase). Our results show that plant-available N released from thawing permafrost can form a thus far overlooked additional N-source for deep-rooting subarctic plant species and increase their biomass production beyond the already established impact of warming-driven enhanced shallow N-mineralization. This may result in shifts in plant community composition and may partially counteract the increased carbon losses from thawing permafrost. © 2017 John Wiley & Sons Ltd.

Exponential Nutrient Loading as a Means to Optimize Bareroot Nursery Fertility of Oak Species

Treesearch

Zonda K. D. Birge; Douglass F. Jacobs; Francis K. Salifu

2006-01-01

Conventional fertilization in nursery culture of hardwoods may involve supply of equal fertilizer doses at regularly spaced intervals during the growing season, which may create a surplus of available nutrients in the beginning and a deficiency in nutrient availability by the end of the growing season. A method of fertilization termed “exponential nutrient loading” has...

Advancing Analysis of Spatio-Temporal Variations of Soil Nutrients in the Water Level Fluctuation Zone of China’s Three Gorges Reservoir Using Self-Organizing Map

PubMed Central

Ye, Chen; Li, Siyue; Yang, Yuyi; Shu, Xiao; Zhang, Jiaquan; Zhang, Quanfa

2015-01-01

The ~350 km2 water level fluctuation zone (WLFZ) in the Three Gorges Reservoir (TGR) of China, situated at the intersection of terrestrial and aquatic ecosystems, experiences a great hydrological change with prolonged winter inundation. Soil samples were collected in 12 sites pre- (September 2008) and post submergence (June 2009) in the WLFZ and analyzed for soil nutrients. Self-organizing map (SOM) and statistical analysis including multi-way ANOVA, paired-T test, and stepwise least squares multiple regression were employed to determine the spatio-temporal variations of soil nutrients in relation to submergence, and their correlations with soil physical characteristics. Results showed significant spatial variability in nutrients along ~600 km long shoreline of the TGR before and after submergence. There were higher contents of organic matter, total nitrogen (TN), and nitrate (NO3-) in the lower reach and total phosphorus (TP) in the upper reach that were primarily due to the spatial variations in soil particle size composition and anthropogenic activities. Submergence enhanced soil available potassium (K), while significantly decreased soil N, possibly due to the alterations of soil particle size composition and increase in soil pH. In addition, SOM analysis determined important roles of soil pH value, bulk density, soil particle size (i.e., silt and sand) and nutrients (TP, TK, and AK) on the spatial and temporal variations in soil quality. Our results suggest that urban sewage and agricultural runoffs are primary pollutants that affect soil nutrients in the WLFZ of TGR. PMID:25789612

Responses of Wheat Yield, Macro- and Micro-Nutrients, and Heavy Metals in Soil and Wheat following the Application of Manure Compost on the North China Plain.

PubMed

Wang, Fan; Wang, Zhaohui; Kou, Changlin; Ma, Zhenghua; Zhao, Dong

2016-01-01

The recycling of livestock manure in cropping systems is considered to enhance soil fertility and crop productivity. However, there have been no systematic long-term studies of the effects of manure application on soil and crop macro- and micro-nutrients, heavy metals, and crop yields in China, despite their great importance for sustainable crop production and food safety. Thus, we conducted field experiments in a typical cereal crop production area of the North China Plain to investigate the effects of compost manure application rates on wheat yield, as well as on the macro-/micro-nutrients and heavy metals contents of soil and wheat. We found that compost application increased the soil total N and the available K, Fe, Zn, and Mn concentrations, whereas the available P in soil was not affected, and the available Cu decreased. In general, compost application had no significant effects on the grain yield, biomass, and harvest index of winter wheat. However, during 2012 and 2013, the N concentration decreased by 9% and 18% in straw, and by 16% and 12% in grain, respectively. With compost application, the straw P concentration only increased in 2012 but the grain P generally increased, while the straw K concentration tended to decrease and the grain K concentration increased in 2013. Compost application generally increased the Fe and Zn concentrations in straw and grain, whereas the Cu and Mn concentrations decreased significantly compared with the control. The heavy metal concentrations increased at some compost application rates, but they were still within the safe range. The balances of the macro-and micro-nutrients indicated that the removal of nutrients by wheat was compensated for by the addition of compost, whereas the level of N decreased without the application of compost. The daily intake levels of micronutrients via the consumption of wheat grain were still lower than the recommended levels when sheep manure compost was applied, except for that of Mn.

Responses of Wheat Yield, Macro- and Micro-Nutrients, and Heavy Metals in Soil and Wheat following the Application of Manure Compost on the North China Plain

PubMed Central

Wang, Fan; Wang, Zhaohui; Kou, Changlin; Ma, Zhenghua; Zhao, Dong

2016-01-01

The recycling of livestock manure in cropping systems is considered to enhance soil fertility and crop productivity. However, there have been no systematic long-term studies of the effects of manure application on soil and crop macro- and micro-nutrients, heavy metals, and crop yields in China, despite their great importance for sustainable crop production and food safety. Thus, we conducted field experiments in a typical cereal crop production area of the North China Plain to investigate the effects of compost manure application rates on wheat yield, as well as on the macro-/micro-nutrients and heavy metals contents of soil and wheat. We found that compost application increased the soil total N and the available K, Fe, Zn, and Mn concentrations, whereas the available P in soil was not affected, and the available Cu decreased. In general, compost application had no significant effects on the grain yield, biomass, and harvest index of winter wheat. However, during 2012 and 2013, the N concentration decreased by 9% and 18% in straw, and by 16% and 12% in grain, respectively. With compost application, the straw P concentration only increased in 2012 but the grain P generally increased, while the straw K concentration tended to decrease and the grain K concentration increased in 2013. Compost application generally increased the Fe and Zn concentrations in straw and grain, whereas the Cu and Mn concentrations decreased significantly compared with the control. The heavy metal concentrations increased at some compost application rates, but they were still within the safe range. The balances of the macro-and micro-nutrients indicated that the removal of nutrients by wheat was compensated for by the addition of compost, whereas the level of N decreased without the application of compost. The daily intake levels of micronutrients via the consumption of wheat grain were still lower than the recommended levels when sheep manure compost was applied, except for that of Mn. PMID:26771517

Impact of irrigation scheduling on pore water nitrate and phosphate in coastal plains soils with corn production

USDA-ARS?s Scientific Manuscript database

Agriculture is one of the most important sources of nutrient contamination, mainly inorganic nitrogen (N) fertilization of intensive crops, such as corn (Zea mays L). Proper irrigation and nutrient management can reduce nutrient leaching while maintaining crop yield, which is critical in enhancing t...

Sources of nutrients to nearshore areas of a eutrophic estuary: Implications for nutrient-enhanced acidification in Puget Sound

EPA Science Inventory

Ocean acidification has recently been highlighted as a major stressor for coastal organisms. Further work is needed to assess the role of anthropogenic nutrient additions in eutrophied systems on local biological processes, and how this interacts with CO2emission-driven acidific...

Nutrient Loss in Runoff from Turf: Effect on Surface Water Quality

USDA-ARS?s Scientific Manuscript database

Excess nutrients in surface waters may result in enhanced algal blooms and plant growth that can lead to eutrophication and a decline in water quality. The applicatin of fertilizer to golf courses may be a source of nutrients to surface waters. Runoff studies were conducted to measure applied nitrog...

Fall fertilization enhanced nitrogen storage and translocation in Larix olgensis seedlings

Treesearch

Y. Zhu; R. K. Dumroese; G. L. Li; J. R. Pinto; Y. Liu

2013-01-01

Fall nutrient loading of deciduous forest nursery seedlings is of special interest because of foliage abscission and varied translocation patterns. For non-deciduous seedlings in the nursery, fall fertilization typically can reverse nutrient dilution and possibly increase nutrient reserves; however, this technique has received little attention with deciduous conifer...

Iron deficiency-induced changes in growth reveal differences in nutrient partitioning between two ecotypes of Medicago truncatula

USDA-ARS?s Scientific Manuscript database

Enhancing the nutritional quality of crops is of international importance, and multiple methods have been utilized to increase the nutrient content of legume seeds. Because nutrients mobilized from source leaves to growing reproductive sink tissues greatly contribute to the final composition of the ...

Physiological Responses of Two Epiphytic Bryophytes to Nitrogen, Phosphorus and Sulfur Addition in a Subtropical Montane Cloud Forest

PubMed Central

Chen, Xi; Liu, Wen-yao; Song, Liang; Li, Su; Wu, Yi; Shi, Xian-meng; Huang, Jun-biao; Wu, Chuan-sheng

2016-01-01

Atmospheric depositions pose significant threats to biodiversity and ecosystem function. However, the underlying physiological mechanisms are not well understood, and few studies have considered the combined effects and interactions of multiple pollutants. This in situ study explored the physiological responses of two epiphytic bryophytes to combined addition of nitrogen, phosphorus and sulfur. We investigated the electrical conductivity (EC), total chlorophyll concentration (Chl), nutrient stoichiometry and chlorophyll fluorescence signals in a subtropical montane cloud forest in south-west China. The results showed that enhanced fertilizer additions imposed detrimental effects on bryophytes, and the combined enrichment of simulated fertilization exerted limited synergistic effects in their natural environments. On the whole, EC, Chl, the effective quantum yield of photosystem II (ΦPSII) and photochemical quenching (qP) were the more reliable indicators of increased artificial fertilization. However, conclusions on nutrient stoichiometry should be drawn cautiously concerning the saturation uptake and nutrient interactions in bryophytes. Finally, we discuss the limitations of prevailing fertilization experiments and emphasize the importance of long-term data available for future investigations. PMID:27560190

Plant growth improvement mediated by nitrate capture in co-composted biochar

PubMed Central

Kammann, Claudia I.; Schmidt, Hans-Peter; Messerschmidt, Nicole; Linsel, Sebastian; Steffens, Diedrich; Müller, Christoph; Koyro, Hans-Werner; Conte, Pellegrino; Stephen, Joseph

2015-01-01

Soil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting considerably promoted biochars’ positive effects, largely by nitrate (nutrient) capture and delivery. In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a sandy-poor soil amended with 2% (w/w) co-composted biochar (BCcomp). Conversely, addition of 2% (w/w) untreated biochar (BCpure) decreased the biomass to 60% of the control. Growth-promoting (BCcomp) as well as growth-reducing (BCpure) effects were more pronounced at lower nutrient-supply levels. Electro-ultra filtration and sequential biochar-particle washing revealed that co-composted biochar was nutrient-enriched, particularly with the anions nitrate and phosphate. The captured nitrate in BCcomp was (1) only partly detectable with standard methods, (2) largely protected against leaching, (3) partly plant-available, and (4) did not stimulate N2O emissions. We hypothesize that surface ageing plus non-conventional ion-water bonding in micro- and nano-pores promoted nitrate capture in biochar particles. Amending (N-rich) bio-waste with biochar may enhance its agronomic value and reduce nutrient losses from bio-wastes and agricultural soils. PMID:26057083

Plant growth improvement mediated by nitrate capture in co-composted biochar

NASA Astrophysics Data System (ADS)

Kammann, Claudia I.; Schmidt, Hans-Peter; Messerschmidt, Nicole; Linsel, Sebastian; Steffens, Diedrich; Müller, Christoph; Koyro, Hans-Werner; Conte, Pellegrino; Stephen, Joseph

2015-06-01

Soil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting considerably promoted biochars’ positive effects, largely by nitrate (nutrient) capture and delivery. In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a sandy-poor soil amended with 2% (w/w) co-composted biochar (BCcomp). Conversely, addition of 2% (w/w) untreated biochar (BCpure) decreased the biomass to 60% of the control. Growth-promoting (BCcomp) as well as growth-reducing (BCpure) effects were more pronounced at lower nutrient-supply levels. Electro-ultra filtration and sequential biochar-particle washing revealed that co-composted biochar was nutrient-enriched, particularly with the anions nitrate and phosphate. The captured nitrate in BCcomp was (1) only partly detectable with standard methods, (2) largely protected against leaching, (3) partly plant-available, and (4) did not stimulate N2O emissions. We hypothesize that surface ageing plus non-conventional ion-water bonding in micro- and nano-pores promoted nitrate capture in biochar particles. Amending (N-rich) bio-waste with biochar may enhance its agronomic value and reduce nutrient losses from bio-wastes and agricultural soils.

ULK1, mammalian target of rapamycin, and mitochondria: linking nutrient availability and autophagy.

PubMed

Kundu, Mondira

2011-05-15

A fundamental function of autophagy conserved from yeast to mammals is mobilization of macromolecules during times of limited nutrient availability, permitting organisms to survive under starvation conditions. In yeast, autophagy is initiated following nitrogen or carbon deprivation, and autophagy mutants die rapidly under these conditions. Similarly, in mammals, autophagy is upregulated in most organs following initiation of starvation, and is critical for survival in the perinatal period following abrupt termination of the placental nutrient supply. The nutrient-sensing kinase, mammalian target of rapamycin, coordinates cellular proliferation and growth with nutrient availability, at least in part by regulating protein synthesis and autophagy-mediated degradation. This review focusses on the regulation of autophagy by Tor, a mammalian target of rapamycin, and Ulk1, a mammalian homolog of Atg1, in response to changes in nutrient availability. Given the importance of mitochondria in maintaining bioenergetic homestasis, and potentially as a source of membrane for autophagosomes during starvation, possible roles for mitochondria in this process are also discussed.

Assessment of bacterial and fungal growth on natural substrates: consequences for preserving caves with prehistoric paintings.

PubMed

Stomeo, Francesca; Portillo, Maria C; Gonzalez, Juan M

2009-09-01

The most representative bacterium (Pseudonocardia sp.) and fungus (Fusarium sp.) from the microbial communities of a cave containing paleolithic paintings were isolated and their growth on natural substrates assessed. Growth was tested at the in situ and optimal, laboratory growth temperature. Development was analyzed with and without supplemented nutrients (glucose, ammonium, phosphate, peptone). Results showed that the assayed bacterium on natural substrate was able to develop best at in situ temperature and the addition of organic nutrients and/or phosphate enhanced its growth. The growth of the assayed fungus, however, was limited by low temperature and the availability of ammonium. These results confirm a differential behavior of microorganisms between the laboratory and the natural environments and could explain previous invasion of fungi reported for some caves with prehistoric paintings.

Data-model synthesis of grassland carbon metabolism. Quantifying direct, indirect & interactive effects of warming & elevated CO 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pendall, Elise; Ogle, Kiona; Parton, William

2016-02-29

This research project improved understanding of how climate change (elevated atmospheric CO 2, warming and altered precipitation) can affect grassland ecosystem productivity and nutrient availability. Our advanced experimental and modeling methods allowed us to test 21 specific hypotheses. We found that ecosystem changes over years of exposure to climate change can shift the plant communities and potentially make them more resilient to future climate changes. These changes in plant communities may be related to increased growth of belowground roots and enhanced nutrient uptake by some species. We also found that climate change can increase the spread of invasive and noxiousmore » weeds. These findings are important for land managers to make adaptive planning decisions for domestic livestock production in response to climate variability in semi-arid grasslands.« less

Enhancement of in situ microbial remediation of aquifers

DOEpatents

Fredrickson, James K.; Brockman, Fred J.; Streile, Gary P.; Cary, John W.; McBride, John F.

1993-01-01

Methods are provided for remediating subsurface areas contaminated by toxic organic compounds. An innocuous oil, such as vegetable oil, mineral oil, or other immiscible organic liquid, is introduced into the contaminated area and permitted to move therethrough. The oil concentrates or strips the organic contaminants, such that the concentration of the contaminants is reduced and such contaminants are available to be either pumped out of the subsurface area or metabolized by microorganisms. Microorganisms may be introduced into the contaminated area to effect bioremediation of the contamination. The methods may be adapted to deliver microorganisms, enzymes, nutrients and electron donors to subsurface zones contaminated by nitrate in order to stimulate or enhance denitrification.

Enhancement of in situ microbial remediation of aquifers

DOEpatents

Fredrickson, J.K.; Brockman, F.J.; Streile, G.P.; Cary, J.W.; McBride, J.F.

1993-11-30

Methods are provided for remediating subsurface areas contaminated by toxic organic compounds. An innocuous oil, such as vegetable oil, mineral oil, or other immiscible organic liquid, is introduced into the contaminated area and permitted to move therethrough. The oil concentrates or strips the organic contaminants, such that the concentration of the contaminants is reduced and such contaminants are available to be either pumped out of the subsurface area or metabolized by microorganisms. Microorganisms may be introduced into the contaminated area to effect bioremediation of the contamination. The methods may be adapted to deliver microorganisms, enzymes, nutrients and electron donors to subsurface zones contaminated by nitrate in order to stimulate or enhance denitrification. 4 figures.

Integration of Carbon, Nitrogen, and Oxygen Metabolism in Escherichia coli--Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rabinowitz, Joshua D; Wingreen, Ned s; Rabitz, Herschel A

2012-10-22

A key challenge for living systems is balancing utilization of multiple elemental nutrients, such as carbon, nitrogen, and oxygen, whose availability is subject to environmental fluctuations. As growth can be limited by the scarcity of any one nutrient, the rate at which each nutrient is assimilated must be sensitive not only to its own availability, but also to that of other nutrients. Remarkably, across diverse nutrient conditions, E. coli grows nearly optimally, balancing effectively the conversion of carbon into energy versus biomass. To investigate the link between the metabolism of different nutrients, we quantified metabolic responses to nutrient perturbations usingmore » LC-MS based metabolomics and built differential equation models that bridge multiple nutrient systems. We discovered that the carbonaceous substrate of nitrogen assimilation, -ketoglutarate, directly inhibits glucose uptake and that the upstream glycolytic metabolite, fructose-1,6-bisphosphate, ultrasensitively regulates anaplerosis to allow rapid adaptation to changing carbon availability. We also showed that NADH controls the metabolic response to changing oxygen levels. Our findings support a general mechanism for nutrient integration: limitation for a nutrient other than carbon leads to build-up of the most closely related product of carbon metabolism, which in turn feedback inhibits further carbon uptake.« less

Kinetic parameters for nutrient enhanced crude oil biodegradation in intertidal marine sediments

PubMed Central

Singh, Arvind K.; Sherry, Angela; Gray, Neil D.; Jones, D. Martin; Bowler, Bernard F. J.; Head, Ian M.

2014-01-01

Availability of inorganic nutrients, particularly nitrogen and phosphorous, is often a primary control on crude oil hydrocarbon degradation in marine systems. Many studies have empirically determined optimum levels of inorganic N and P for stimulation of hydrocarbon degradation. Nevertheless, there is a paucity of information on fundamental kinetic parameters for nutrient enhanced crude oil biodegradation that can be used to model the fate of crude oil in bioremediation programmes that use inorganic nutrient addition to stimulate oil biodegradation. Here we report fundamental kinetic parameters (Ks and qmax) for nitrate- and phosphate-stimulated crude oil biodegradation under nutrient limited conditions and with respect to crude oil, under conditions where N and P are not limiting. In the marine sediments studied, crude oil degradation was limited by both N and P availability. In sediments treated with 12.5 mg/g of oil but with no addition of N and P, hydrocarbon degradation rates, assessed on the basis of CO2 production, were 1.10 ± 0.03 μmol CO2/g wet sediment/day which were comparable to rates of CO2 production in sediments to which no oil was added (1.05 ± 0.27 μmol CO2/g wet sediment/day). When inorganic nitrogen was added alone maximum rates of CO2 production measured were 4.25 ± 0.91 μmol CO2/g wet sediment/day. However, when the same levels of inorganic nitrogen were added in the presence of 0.5% P w/w of oil (1.6 μmol P/g wet sediment) maximum rates of measured CO2 production increased more than four-fold to 18.40 ± 1.04 μmol CO2/g wet sediment/day. Ks and qmax estimates for inorganic N (in the form of sodium nitrate) when P was not limiting were 1.99 ± 0.86 μmol/g wet sediment and 16.16 ± 1.28 μmol CO2/g wet sediment/day respectively. The corresponding values for P were 63 ± 95 nmol/g wet sediment and 12.05 ± 1.31 μmol CO2/g wet sediment/day. The qmax values with respect to N and P were not significantly different (P < 0.05). When N and P were not limiting Ks and qmax for crude oil were 4.52 ± 1.51 mg oil/g wet sediment and 16.89 ± 1.25 μmol CO2/g wet sediment/day. At concentrations of inorganic N above 45 μmol/g wet sediment inhibition of CO2 production from hydrocarbon degradation was evident. Analysis of bacterial 16S rRNA genes indicated that Alcanivorax spp. were selected in these marine sediments with increasing inorganic nutrient concentration, whereas Cycloclasticus spp. were more prevalent at lower inorganic nutrient concentrations. These data suggest that simple empirical estimates of the proportion of nutrients added relative to crude oil concentrations may not be sufficient to guarantee successful crude oil bioremediation in oxic beach sediments. The data we present also help define the maximum rates and hence timescales required for bioremediation of beach sediments. PMID:24782848

Effects of poultry litter injection on ammonia volatilization, nitrogen availability, and nutrient losses in runoff

USDA-ARS?s Scientific Manuscript database

Poultry litter is a common organic amendment in agricultural production systems, but nutrient losses can reduce the effectiveness as a fertilizer. Three studies were conducted to determine differences in nutrient availability and loss when comparing injection and surface application. These investi...

Improvement of water and light availability after thinning at a xeric site: which matters more? A dual isotope approach.

PubMed

Giuggiola, Arnaud; Ogée, Jérôme; Rigling, Andreas; Gessler, Arthur; Bugmann, Harald; Treydte, Kerstin

2016-04-01

Thinning fosters individual tree growth by increasing the availability of water, light and nutrients. At sites where water rather than light is limiting, thinning also enhances soil evaporation and might not be beneficial. Detailed knowledge of the short- to long-term physiological response underlying the growth responses to thinning is crucial for the management of forests already suffering from recurrent drought-induced dieback. We applied a dual isotope approach together with mechanistic isotope models to study the physiological processes underlying long-term growth enhancement of heavily thinned Pinus sylvestris in a xeric forest in Switzerland. This approach allowed us to identify and disentangle thinning-induced changes in stomatal conductance and assimilation rate. At our xeric study site, the increase in stomatal conductance far outweighed the increase in assimilation, implying that growth release in heavily thinned trees is primarily driven by enhanced water availability rather than increased light availability. We conclude that in forests with relatively isohydric species (drought avoiders) that are growing close to their physiological limits, thinning is recommended to maintain a less negative water balance and thus foster tree growth, and ultimately the survival of forest trees under drought. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Soil nutrient availability and reproductive effort drive patterns in nutrient resorption in Pentachlethra macroloba

Treesearch

K. L. Tully; Tana Wood; A. M. Schwantes; D. Lawrence

2013-01-01

The removal of nutrients from senescing tissues, nutrient resorption, is a key strategy for conserving nutrients in plants. However, our understanding of what drives patterns of nutrient resorption in tropical trees is limited. We examined the effects of nutrient sources (stand-level and tree-level soil fertility) and sinks (reproductive effort) on nitrogen (N) and...

Removal of nutrient limitations by long-term fertilization decreases nocturnal water loss in savanna trees.

Treesearch

F.G. Scholz; S.J. Bucci; G. Goldstein; F.C. Meinzer; A.C. Franco; F. Miralles-Wilhelm

2007-01-01

Under certain environmental conditions, nocturnal transpiration can be relatively high in temperate and tropical woody species. In nutrient-poor systems such as the Brazilian Cerrado, nocturnal transpiration may enhance delivery of nutrients to roots. We compared nocturnal transpiration of three dominant Cerrado tree species growing in unfertilized plots and plots to...

Numerical modelling of biophysicochemical effects on multispecies reactive transport in porous media involving Pseudomonas putida for potential microbial enhanced oil recovery application.

PubMed

Sivasankar, P; Rajesh Kanna, A; Suresh Kumar, G; Gummadi, Sathyanarayana N

2016-07-01

pH and resident time of injected slug plays a critical role in characterizing the reservoir for potential microbial enhanced oil recovery (MEOR) application. To investigate MEOR processes, a multispecies (microbes-nutrients) reactive transport model in porous media was developed by coupling kinetic and transport model. The present work differs from earlier works by explicitly determining parametric values required for kinetic model by experimental investigations using Pseudomonas putida at different pH conditions and subsequently performing sensitivity analysis of pH, resident time and water saturation on concentrations of microbes, nutrients and biosurfactant within reservoir. The results suggest that nutrient utilization and biosurfactant production are found to be maximum at pH 8 and 7.5 respectively. It is also found that the sucrose and biosurfactant concentrations are highly sensitive to pH rather than reservoir microbial concentration, while at larger resident time and water saturation, the microbial and nutrient concentrations were lesser due to enhanced dispersion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bench-scale evaluation of in situ bioremediation strategies for soil at a former manufactured gas plant site.

PubMed

Li, Jun; Pignatello, Joseph J; Smets, Barth F; Grasso, Domenico; Monserrate, Esteban

2005-03-01

We examined the biodegradation and desorption of a set of 15 polycyclic aromatic hydrocarbon (PAH) compounds in coal tar-contaminated soil at a former manufactured gas plant site to evaluate the feasibility of in situ bioremediation. Experiments were conducted in well-mixed aerobic soil suspensions containing various additives over a 93- to 106-d period. In general, both biotransformation and desorption decreased with PAH ring size, becoming negligible for the six-ring PAH compounds. Biodegradation by indigenous microorganisms was strongly accelerated by addition of inorganic nutrients (N, P, K, and trace metals). The rates of biotransformation of PAH compounds by indigenous microorganisms in nutrient-amended flasks outpaced their maximum (i.e., chelate-enhanced) rates of desorption to an infinite sink (Tenax) in sterilized systems run in parallel, suggesting that indigenous organisms facilitated desorption. Biodegradation by indigenous organisms in nutrient-amended flasks appeared to be unaffected by the addition of a site-derived bacterial enrichment culture, resulting in approximately 100-fold higher aromatic dioxygenase levels, and by the addition of 0.01 M chelating agent (citrate or pyrophosphate), although such chelating agents greatly enhanced desorption in microbially inactivated flasks. The strong ability of nutrients to enhance degradation of the bioavailable PAHs indicates that their persistence for many decades at this site likely results from nutrient-limited natural biodegradation, and it also suggests that an effective strategy for their bioremediation could consist simply of adding inorganic nutrients.

Using Hyperspectral Aircraft Remote Sensing to Support Ecosystems Services Research in New England Lakes and Ponds

NASA Astrophysics Data System (ADS)

Keith, D. J.; Milstead, B.; Walker, H.; Worthy, D.; Szykman, J.; Wusk, M.; Kagey, L.; Howell, C.; Snook, H.; Drueke, C.

2010-12-01

Northeastern lakes and ponds provide important ecosystem services to New England residents and visitors. These include the provisioning of abundant, clean water for consumption, agriculture, and industry as well as cultural services (recreation, aesthetics, and wilderness experiences) which enhance local economies and quality of life. Less understood, but equally important, are the roles that these lakes play in protecting all life through supportive services such as nutrient cycling. Nitrogen and phosphorus have a direct impact on the condition of fresh water lakes. Excesses of these nutrients can lead to eutrophication, toxic cyanobacteria blooms, decreased biodiversity, and loss of ecosystem function leading to a reduction in the availability and delivery of ecosystem services. In this study, we examined how variations in lake nutrient concentrations and phytoplankton pigment concentrations correlated with changes in the potential to provide cultural ecosystem services. Using a NASA Cessna 206 aircraft, hyperspectral data were collected during late summer 2009 from 55 lakes in New Hampshire, Massachusetts, Connecticut, and Rhode Island over a 2 day period. From the spectral data, algorithms were created which estimated concentrations of chlorophyll a, phycocyanin, and colored dissolved organic matter. The remotely sensed estimates were supplemented by in situ chlorophyll a, total nitrogen, total phosphorus and lake color data from 43 lakes sampled by field crews from the New England states. The purpose of this research is to understand how variations in lake nutrient concentrations and phytoplankton pigment concentrations correlate with changes in availability of cultural ecosystem services in the surveyed lakes. This dataset will be combined with information from the EPA National Lake Survey (2007), the EPA New England Lakes and Ponds Survey (2008) and the USGS SPARROW model to explore the association between lake condition and the provisioning of ecosystem services on a regional scale. Under the EPA Ecological Services Research Program (ESRP), this information will provide managers and researchers with a better understanding of links between management decisions affecting nutrient fluxes and impacts on selected ecosystem services.

Analysis of field-scale spatial correlations and variations of soil nutrients using geostatistics.

PubMed

Liu, Ruimin; Xu, Fei; Yu, Wenwen; Shi, Jianhan; Zhang, Peipei; Shen, Zhenyao

2016-02-01

Spatial correlations and soil nutrient variations are important for soil nutrient management. They help to reduce the negative impacts of agricultural nonpoint source pollution. Based on the sampled available nitrogen (AN), available phosphorus (AP), and available potassium (AK), soil nutrient data from 2010, the spatial correlation, was analyzed, and the probabilities of the nutrient's abundance or deficiency were discussed. This paper presents a statistical approach to spatial analysis, the spatial correlation analysis (SCA), which was originally developed for describing heterogeneity in the presence of correlated variation and based on ordinary kriging (OK) results. Indicator kriging (IK) was used to assess the susceptibility of excess of soil nutrients based on crop needs. The kriged results showed there was a distinct spatial variability in the concentration of all three soil nutrients. High concentrations of these three soil nutrients were found near Anzhou. As the distance from the center of town increased, the concentration of the soil nutrients gradually decreased. Spatially, the relationship between AN and AP was negative, and the relationship between AP and AK was not clear. The IK results showed that there were few areas with a risk of AN and AP overabundance. However, almost the entire study region was at risk of AK overabundance. Based on the soil nutrient distribution results, it is clear that the spatial variability of the soil nutrients differed throughout the study region. This spatial soil nutrient variability might be caused by different fertilizer types and different fertilizing practices.

Grafting: A Technique to Modify Ion Accumulation in Horticultural Crops

PubMed Central

Nawaz, Muhammad A.; Imtiaz, Muhammad; Kong, Qiusheng; Cheng, Fei; Ahmed, Waqar; Huang, Yuan; Bie, Zhilong

2016-01-01

Grafting is a centuries-old technique used in plants to obtain economic benefits. Grafting increases nutrient uptake and utilization efficiency in a number of plant species, including fruits, vegetables, and ornamentals. Selected rootstocks of the same species or close relatives are utilized in grafting. Rootstocks absorb more water and ions than self-rooted plants and transport these water and ions to the aboveground scion. Ion uptake is regulated by a complex communication mechanism between the scion and rootstock. Sugars, hormones, and miRNAs function as long-distance signaling molecules and regulate ion uptake and ion homeostasis by affecting the activity of ion transporters. This review summarizes available information on the effect of rootstock on nutrient uptake and utilization and the mechanisms involved. Information on specific nutrient-efficient rootstocks for different crops of commercial importance is also provided. Several other important approaches, such as interstocking (during double grafting), inarching, use of plant-growth-promoting rhizobacteria, use of arbuscular mycorrhizal fungi, use of plant growth substances (e.g., auxin and melatonin), and use of genetically engineered rootstocks and scions (transgrafting), are highlighted; these approaches can be combined with grafting to enhance nutrient uptake and utilization in commercially important plant species. Whether the rootstock and scion affect each other's soil microbiota and their effect on the nutrient absorption of rootstocks remain largely unknown. Similarly, the physiological and molecular bases of grafting, crease formation, and incompatibility are not fully identified and require investigation. Grafting in horticultural crops can help reveal the basic biology of grafting, the reasons for incompatibility, sensing, and signaling of nutrients, ion uptake and transport, and the mechanism of heavy metal accumulation and restriction in rootstocks. Ion transporter and miRNA-regulated nutrient studies have focused on model and non-grafted plants, and information on grafted plants is limited. Such information will improve the development of nutrient-efficient rootstocks. PMID:27818663

Cumulative Effects of Nutrient Enrichment and Elevated Temperature Compromise the Early Life History Stages of the Coral Acropora tenuis

PubMed Central

Noonan, Sam H. C.; Willis, Bette L.; Fabricius, Katharina E.; Negri, Andrew P.

2016-01-01

Inshore coral reefs are experiencing the combined pressures of excess nutrient availability associated with coastal activities and warming seawater temperatures. Both pressures are known to have detrimental effects on the early life history stages of hard corals, but studies of their combined effects on early demographic stages are lacking. We conducted a series of experiments to test the combined effects of nutrient enrichment (three levels) and elevated seawater temperature (up to five levels) on early life history stages of the inshore coral Acropora tenuis, a common species in the Indo-Pacific and Red Sea. Gamete fertilization, larval survivorship and larval settlement were all significantly reduced as temperature increased, but only fertilization was further affected by simultaneous nutrient enrichment. Combined high temperatures and nutrient enrichment affected fertilization in an additive manner, whereas embryo abnormalities increased synergistically. Higher than normal temperatures (32°C) increased coral juvenile growth rates 1.6-fold, but mortality also increased by 50%. The co-occurrence of nutrient enrichment with high temperatures reduced juvenile mortality to 36%, ameliorating temperature stress (antagonistic interaction). Overall, the types of effect (additive vs synergistic or antagonistic) and their magnitude varied among life stages. Gamete and embryo stages were more affected by temperature stress and, in some cases, also by nutrient enrichment than juveniles. The data suggest that coastal runoff events might exacerbate the impacts of warming temperatures on fertilization if these events co-occur during corals spawning. The cumulative impacts of simultaneous exposure to nutrient enrichment and elevated temperatures over all early life history stages increases the likelihood for failure of larval supply and recruitment for this coral species. Our results suggest that improving the water quality of river discharges into coastal areas might help to enhance the thermal tolerances of early life history stages in this common coral species. PMID:27575699

Microbial and biogeochemical dynamics in glacier forefields are sensitive to century-scale climate and anthropogenic change.

NASA Astrophysics Data System (ADS)

Bradley, James A.; Anesio, Alexandre M.; Arndt, Sandra

2017-04-01

The recent retreat of glaciers and ice sheets as a result of global warming exposes forefield soils that are rapidly colonised by microbes. These ecosystems are dominant in high-latitude carbon and nutrient cycles as microbial activity drives biogeochemical transformations within these newly exposed soils. Despite this, little is known about the response of these emerging ecosystems and associated biogeochemical cycles to projected changes in environmental factors due to human impacts. Here, we applied the model SHIMMER to quantitatively explore the sensitivity of biogeochemical dynamics in the forefield of Midtre Lovénbreen, Svalbard, to future changes in climate and anthropogenic forcings including soil temperature, snow cover, and nutrient and organic substrate deposition. Model results indicated that the rapid warming of the Arctic, as well as an increased deposition of organic carbon and nutrients, may impact primary microbial colonisers in Arctic soils. Warming and increased snow-free conditions resulted in enhanced bacterial production and an accumulation of biomass that was sustained throughout 200 years of soil development. Nitrogen deposition stimulated growth during the first 50 years of soil development following exposure. Increased deposition of organic carbon sustained higher rates of bacterial production and heterotrophic respiration leading to decreases in net ecosystem production and thus net CO2 efflux from soils. Pioneer microbial communities were particularly susceptible to future changes. All future climate simulations encouraged a switch from allochthonously-dominated young soils (<40 years) to microbially-dominated older soils, due to enhanced heterotrophic degradation of organic matter. Critically, this drove remineralisation and increased nutrient availability. Overall, we show that human activity, especially the burning of fossil fuels and the enhanced deposition of nitrogen and organic carbon, has the potential to considerably affect the biogeochemical development of recently exposed Arctic soils in the present day and for centuries into the future. These effects must be acknowledged when attempting to make accurate predictions of the future fate of Arctic soils that are exposed over large expanses of presently ice-covered regions.

Response of Benthic Microalgae to Phosphorus Inputs in Grand Bay National Estuarine Research Reserve

NASA Astrophysics Data System (ADS)

Sleek, J.; Caffrey, J. M.; Baine, G. C., II; Capps, R.

2016-12-01

Benthic microalgae are an important, but often understudied component of shallow, photic estuaries in the Gulf of Mexico. Grand Bay National Estuarine Research Reserve (GBNERR) is located in a small and relatively pristine estuary in the northern Gulf of Mexico. Freshwater input into the estuary is primarily local runoff from bayous and tidal creeks, including Bayou Cumbest, Bayou Heron, and Bangs Lake. Nutrient loading to Grand Bay is relatively small, with ambient nutrient concentrations often below detection. However, several events in 2005, 2012, 2013, and 2014 due to breaches in a containment levee from a gypsum stack have led to high phosphate levels near Bangs Lake. GBNERR staff assembled a phosphate working group to investigate scientific questions related to these phosphate loadings. This working group includes members from GBNERR, regional universities, marine labs, and Mississippi Department of Environmental Quality. In marine ecosystems, nitrogen availability normally limits growth of phytoplankton and previous research has shown this to be the case in Grand Bay. However, little is known about benthic microalgae in Grand Bay and what their response is to these phosphorus inputs. Between 2013 and 2015, summer concentrations of water column and benthic chlorophyll a were positively correlated, with the highest concentrations occurring in Bangs Lake. Benthic chlorophyll was also positively correlated with the percent surface irradiance reaching the bottom. Bottom light levels range from 3 to 36% surface irradiance. This along with experiments that showed no enhancement of growth of benthic microalgae following addition of nutrients (ammonium, phosphate or both) suggest that benthic microalgae are predominantly light limited rather than nutrient limited. Preliminary nitrogen fixation measurements suggest that nitrogen fixation was positively correlated with extractable phosphate concentrations. Thus, enhanced sediment nitrogen fixation and excess phosphate from the fertilizer plant runoff in this high light environment may enhance benthic microalgal production. The results of this research are part of the larger effort by the phosphate working group to understand the impact of repeated phosphate impacts. These results will provide information needed to help manage the reserve.

Response of Benthic Microalgae to Phosphorus Inputs in Grand Bay National Estuarine Research Reserve

NASA Astrophysics Data System (ADS)

Sleek, J.; Caffrey, J. M.; Baine, G. C., II; Capps, R.

2016-02-01

Benthic microalgae are an important, but often understudied component of shallow, photic estuaries in the Gulf of Mexico. Grand Bay National Estuarine Research Reserve (GBNERR) is located in a small and relatively pristine estuary in the northern Gulf of Mexico. Freshwater input into the estuary is primarily local runoff from bayous and tidal creeks, including Bayou Cumbest, Bayou Heron, and Bangs Lake. Nutrient loading to Grand Bay is relatively small, with ambient nutrient concentrations often below detection. However, several events in 2005, 2012, 2013, and 2014 due to breaches in a containment levee from a gypsum stack have led to high phosphate levels near Bangs Lake. GBNERR staff assembled a phosphate working group to investigate scientific questions related to these phosphate loadings. This working group includes members from GBNERR, regional universities, marine labs, and Mississippi Department of Environmental Quality. In marine ecosystems, nitrogen availability normally limits growth of phytoplankton and previous research has shown this to be the case in Grand Bay. However, little is known about benthic microalgae in Grand Bay and what their response is to these phosphorus inputs. Between 2013 and 2015, summer concentrations of water column and benthic chlorophyll a were positively correlated, with the highest concentrations occurring in Bangs Lake. Benthic chlorophyll was also positively correlated with the percent surface irradiance reaching the bottom. Bottom light levels range from 3 to 36% surface irradiance. This along with experiments that showed no enhancement of growth of benthic microalgae following addition of nutrients (ammonium, phosphate or both) suggest that benthic microalgae are predominantly light limited rather than nutrient limited. Preliminary nitrogen fixation measurements suggest that nitrogen fixation was positively correlated with extractable phosphate concentrations. Thus, enhanced sediment nitrogen fixation and excess phosphate from the fertilizer plant runoff in this high light environment may enhance benthic microalgal production. The results of this research are part of the larger effort by the phosphate working group to understand the impact of repeated phosphate impacts. These results will provide information needed to help manage the reserve.

Biological potential of extraterrestrial materials. 2. Microbial and plant responses to nutrients in the Murchison carbonaceous meteorite

NASA Technical Reports Server (NTRS)

Mautner, M. N.; Conner, A. J.; Killham, K.; Deamer, D. W.

1997-01-01

Meteoritic materials are investigated as potential early planetary nutrients. Aqueous extracts of the Murchison C2 carbonaceous meteorite are utilized as a sole carbon source by microorganisms, as demonstrated by the genetically modified Pseudomonas fluorescence equipped with the lux gene. Nutrient effects are observed also with the soil microorganisms Nocardia asteroides and Arthrobacter pascens that reach populations up to 5 x 10(7) CFU/ml in meteorite extracts, similar to populations in terrestrial soil extracts. Plant tissue cultures of Asparagus officinalis and Solanum tuberosum (potato) exhibit enhanced pigmentation and some enhanced growth when meteorite extracts are added to partial nutrient media, but inhibited growth when added to full nutrient solution. The meteorite extracts lead to large increases in S, Ca, Mg, and Fe plant tissue contents as shown by X-ray fluorescence, while P, K, and Cl contents show mixed effects. In both microbiological and plant tissue experiments, the nutrient and inhibitory effects appear to be best balanced for growth at about 1:20 (extracted solid : H2O) ratios. The results suggest that solutions in cavities in meteorites can provide efficient concentrated biogenic and early nutrient environments, including high phosphate levels, which may be the limiting nutrient. The results also suggest that carbonaceous asteroid resources can sustain soil microbial activity and provide essential macronutrients for future space-based ecosystems.

Effect of nutrient amendments on indigenous hydrocarbon biodegradation in oil-contaminated beach sediments.

PubMed

Xu, Ran; Obbard, Jeffrey P

2003-01-01

Nutrient amendment to oil-contaminated beach sediments is a critical factor for the enhancement of indigenous microbial activity and biodegradation of petroleum hydrocarbons in the intertidal marine environment. In this study, we investigated the stimulatory effect of the slow-release fertilizers Osmocote (Os; Scotts, Marysville, OH) and Inipol EAP-22 (Ip; ATOFINA Chemicals, Philadelphia, PA) combined with inorganic nutrients on the bioremediation of oil-spiked beach sediments using an open irrigation system with artificial seawater over a 45-d period. Osmocote is comprised of a semipermeable membrane surrounding water-soluble inorganic N, P, and K. Inipol, which contains organic N and P, has been used for oil cleanup on beach substrate. Nutrient concentrations and microbial activity in sediments were monitored by analyzing sediment leachates and metabolic dehydrogenase activity of the microbial biomass, respectively. Loss of aliphatics (n-C12 to n-C33, pristane, and phytane) was significantly greater (total loss between 95 and 97%) in oil-spiked sediments treated with Os alone or in combination with other nutrient amendments, compared with an unamended oil-spiked control (26% loss) or sediments treated with the other nutrient amendments (28-65% loss). A combination of Os and soluble nutrients (SN) was favorable for the rapid metabolic stimulation of the indigenous microbial biomass, the sustained release of nutrients, and the enhanced biodegradation of petroleum hydrocarbons in leached, oil-contaminated sediments.

Comprehensive Analysis of the Effects of Ordinary Nutrients on Hepatitis C Virus RNA Replication in Cell Culture▿

PubMed Central

Yano, Masahiko; Ikeda, Masanori; Abe, Ken-ichi; Dansako, Hiromichi; Ohkoshi, Shogo; Aoyagi, Yutaka; Kato, Nobuyuki

2007-01-01

To date, only a limited number of studies have reported finding an influence of ordinary nutrients on hepatitis C virus (HCV) RNA replication. However, the effects of other nutrients on HCV RNA replication remain largely unknown. We recently developed a reporter assay system for genome-length HCV RNA replication in hepatoma-derived HuH-7 cells (OR6). Here, using this OR6 assay system, we comprehensively examined 46 nutrients from four nutrient groups: vitamins, amino acids, fatty acids, and salts. We found that three nutrients—β-carotene, vitamin D2, and linoleic acid—inhibited HCV RNA replication and that their combination caused additive and/or synergistic effects on HCV RNA replication. In addition, combined treatment with each of the three nutrients and interferon alpha or beta or fluvastatin inhibited HCV RNA replication in an additive manner, while combined treatment with cyclosporine synergistically inhibited HCV RNA replication. In contrast, we found that vitamin E enhanced HCV RNA replication and negated the effects of the three anti-HCV nutrients and cyclosporine but not those of interferon or fluvastatin. These results will provide useful information for the treatment of chronic hepatitis C patients who also take anti-HCV nutrients as an adjunctive therapy in combination with interferon. In conclusion, among the ordinary nutrients tested, β-carotene, vitamin D2, and linoleic acid possessed anti-HCV activity in a cell culture system, and these nutrients are therefore considered to be potential candidates for enhancing the effects of interferon therapy. PMID:17420205

The effect of nutrient enrichment on growth, photosynthesis and hydraulic conductance of dwarf mangroves in Panamá

USGS Publications Warehouse

Lovelock, C.E.; Feller, Ilka C.; McKee, K.L.; Engelbrecht, B.M.J.; Ball, M.C.

2004-01-01

1. Dwarf stands of the mangrove Rhizophora mangle L. are extensive in the Caribbean. We fertilized dwarf trees in Almirante Bay, Bocas del Toro Province, north-eastern Panama with nitrogen (N) and phosphorus (P) to determine (1) if growth limitations are due to nutrient deficiency; and (2) what morphological and/or physiological factors underlie nutrient limitations to growth. 2. Shoot growth was 10-fold when fertilized with P and twofold with N fertilization, indicating that stunted growth of these mangroves is partially due to nutrient deficiency. 3. Growth enhancements caused by N or P enrichment could not be attributed to increases in photosynthesis on a leaf area basis, although photosynthetic nutrient-use efficiency was improved. The most dramatic effect was on stem hydraulic conductance, which was increased sixfold by P and 2-5-fold with N enrichment. Fertilization with P enhanced leaf and stem P concentrations and reduced C:N ratio, but did not alter leaf damage by herbivores. 4. Our findings indicate that addition of N and P significantly alter tree growth and internal nutrient dynamics of mangroves at Bocas del Toro, but also that the magnitude, pattern and mechanisms of change will be differentially affected by each nutrient.

Food crop production, nutrient availability, and nutrient intakes in Bangladesh: exploring the agriculture-nutrition nexus with the 2010 Household Income and Expenditure Survey.

PubMed

Fiedler, John L

2014-12-01

Systematic collection of national agricultural data has been neglected in many low- and middle-income countries for the past 20 years. Commonly conducted nationally representative household surveys collect substantial quantities of highly underutilized food crop production data. To demonstrate the potential usefulness of commonly available household survey databases for analyzing the agriculture-nutrition nexus. Using household data from the 2010 Bangladesh Household Income and Expenditure Survey, the role and significance of crop selection, area planted, yield, nutrient production, and the disposition of 34 food crops in affecting the adequacy of farming households' nutrient availability and nutrient intake status are explored. The adequacy of each farming household's available energy, vitamin A, calcium, iron, and zinc and households' apparent intakes and intake adequacies are estimated. Each household's total apparent nutrient intake adequacies are estimated, taking into account the amount of each crop that households consume from their own production, together with food purchased or obtained from other sources. Even though rice contains relatively small amounts of micronutrients, has relatively low nutrient density, and is a relatively poor source of nutrients compared with what other crops can produce on a given tract of land, because so much rice is produced in Bangladesh, it is the source of 90% of the total available energy, 85% of the zinc, 67% of the calcium, and 55% of the iron produced by the agricultural sector. The domination of agriculture and diet by rice is a major constraint to improving nutrition in Bangladesh. Simple examples of how minor changes in the five most common cropping patterns could improve farming households' nutritional status are provided. Household surveys' agricultural modules can provide a useful tool for better understanding national nutrient production realities and possibilities.

Effects of burn temperature on ash nutrient forms and availability from cattail (Typha domingensis) and sawgrass (Cladium jamaicense) in the Florida Everglades.

PubMed

Qian, Y; Miao, S L; Gu, B; Li, Y C

2009-01-01

Plant ash derived from fire plays an important role in nutrient balance and cycling in ecosystems. Factors that determine the composition and availability of ash nutrients include fire intensity (burn temperature and duration), plant species, habitat nutrient enrichment, and leaf type (live or dead leaf). We used laboratory simulation methods to evaluate temperature effects on nutrient composition and metals in the residual ash of sawgrass (Cladium jamaicense) and cattail (Typha domingensis), particularly on post-fire phosphorus (P) availability in plant ash. Live and dead leaf samples were collected from Water Conservation Area 2A in the northern Everglades along a soil P gradient, where prescribed fire may be used to accelerate recovery of this unique ecosystem. Significant decreases in total carbon and total nitrogen were detected with increasing fire temperature. Organic matter combustion was nearly complete at temperatures > or = 450 degrees C. HCl-extractable P (average, 50% of total P in the ash) and NH(4)Cl-extractable P (average, 33% of total P in the ash) were the predominant P fractions for laboratory-burned ash. Although a low-intensity fire could induce an elevation of P availability, an intense fire generally resulted in decreased water-soluble P. Significant differences in nutrient compositions were observed between species, habitat nutrient status, and leaf types. More labile inorganic P remained in sawgrass ash than in cattail ash; hence, sawgrass ash has a greater potential to release available P than cattail. Fire intensity affected plant ash nutrient composition, particularly P availability, and the effects varied with plant species and leaf type. Therefore, it is important to consider fire intensity and vegetation community when using a prescribed fire for ecosystem management.

Nutrient and other environmental controls of harmful cyanobacterial blooms along the freshwater-marine continuum.

PubMed

Paerl, Hans

2008-01-01

Nutrient and hydrologic conditions strongly influence harmful planktonic and benthic cyanobacterial bloom (CHAB) dynamics in aquatic ecosystems ranging from streams and lakes to coastal ecosystems. Urbanization, agricultural and industrial development have led to increased nitrogen (N) and phosphorus (P) discharge, which affect CHAB potentials of receiving waters. The amounts, proportions and chemical composition of N and P sources can influence the composition, magnitude and duration of blooms. This, in turn, has ramifications for food web dynamics (toxic or inedible CHABs), nutrient and oxygen cycling and nutrient budgets. Some CHABs are capable of N2 fixation, a process that can influence N availability and budgets. Certain invasive N2 fixing taxa (e.g., Cylindrospermopsis, Lyngbya) also effectively compete for fixed N during spring, N-enriched runoff periods, while they use N2 fixation to supplant their N needs during N-deplete summer months. Control of these taxa is strongly dependent on P supply. However, additional factors, such as molar N:P supply ratios, organic matter availability, light attenuation, freshwater discharge, flushing rates (residence time) and water column stability play interactive roles in determining CHAB composition (i.e. N2 fixing vs. non-N2 fixing taxa) and biomass. Bloom potentials of nutrient-impacted waters are sensitive to water residence (or flushing) time, temperatures (preference for > 15 degrees C), vertical mixing and turbidity. These physical forcing features can control absolute growth rates of bloom taxa. Human activities may affect "bottom up" physical-chemical modulators either directly, by controlling hydrologic, nutrient, sediment and toxic discharges, or indirectly, by influencing climate. Control and management of cyanobacterial and other phytoplankton blooms invariably includes nutrient input constraints, most often focused on N and/or P. While single nutrient input constraints may be effective in some water bodies, dual N and P input reductions are usually required for effective long-term control and management of blooms. In some systems where hydrologic manipulations (i.e., plentiful water supplies) are possible, reducing the water residence time by flushing and artificial mixing (along with nutrient input constraints) can be effective alternatives. Blooms that are not readily consumed and transferred up the food web will form a relatively large proportion of sedimented organic matter. This, in turn, will exacerbate sediment oxygen demand, and enhance the potential for oxygen depletion and release of nutrients back to the water column. This scenario is particularly problematic in long-residence time (i.e., months) systems, where blooms may exert a strong positive feedback on future events. Implications of these scenarios and the confounding issues of climatic (hydrologic) variability, including droughts, tropical storms, hurricanes and floods, will be discussed in the context of developing effective CHAB control strategies along the freshwater-marine continuum.

Plant Nutrition 2: Macronutrients (N, P, K, S, Mg, and Ca)

PubMed Central

2014-01-01

Summary In the second of three lessons spanning the topic of Plant Nutrition, we examine how macronutrients affect plant growth. Specifically, we look at (1) the availability of nutrients in the soil along with the effects of soil microbes and physical properties on their availability; (2) nutrient uptake from the external environment, across plasma membranes and into plant cells; (3) in some cases, the assimilation of the nutrient into organic molecules; (4) the distribution and redistribution of nutrients throughout the plant; and (5) regulation of these processes. In parallel, we examine the genetic basis of a plant's nutrient use efficiency (NUE) and evaluate strategies by which to replenish nutrients that growing plants extract from soil.

Efficacy of algal metrics for assessing nutrient and organic enrichment in flowing waters

USGS Publications Warehouse

Porter, S.D.; Mueller, D.K.; Spahr, N.E.; Munn, M.D.; Dubrovsky, N.M.

2008-01-01

4. Although algal species tolerance to nutrient and organic enrichment is well documented, additional taxonomic and autecological research on sensitive, endemic algal species would further enhance water-quality assessments.

ULK1, Mammalian Target of Rapamycin, and Mitochondria: Linking Nutrient Availability and Autophagy

PubMed Central

2011-01-01

Abstract A fundamental function of autophagy conserved from yeast to mammals is mobilization of macromolecules during times of limited nutrient availability, permitting organisms to survive under starvation conditions. In yeast, autophagy is initiated following nitrogen or carbon deprivation, and autophagy mutants die rapidly under these conditions. Similarly, in mammals, autophagy is upregulated in most organs following initiation of starvation, and is critical for survival in the perinatal period following abrupt termination of the placental nutrient supply. The nutrient-sensing kinase, mammalian target of rapamycin, coordinates cellular proliferation and growth with nutrient availability, at least in part by regulating protein synthesis and autophagy-mediated degradation. This review focusses on the regulation of autophagy by Tor, a mammalian target of rapamycin, and Ulk1, a mammalian homolog of Atg1, in response to changes in nutrient availability. Given the importance of mitochondria in maintaining bioenergetic homestasis, and potentially as a source of membrane for autophagosomes during starvation, possible roles for mitochondria in this process are also discussed. Antioxid. Redox Signal. 14, 1953–1958. PMID:21235397

[Spatial variability of surface soil nutrients in the landslide area of Beichuan County, South- west China, after 5 · 12 Wenchuan Earthquake].

PubMed

Mai, Ji-shan; Zhao, Ting-ning; Zheng, Jiang-kun; Shi, Chang-qing

2015-12-01

Based on grid sampling and laboratory analysis, spatial variability of surface soil nutrients was analyzed with GS⁺ and other statistics methods on the landslide area of Fenghuang Mountain, Leigu Town, Beichuan County. The results showed that except for high variability of available phosphorus, other soil nutrients exhibited moderate variability. The ratios of nugget to sill of the soil available phosphorus and soil organic carbon were 27.9% and 28.8%, respectively, showing moderate spatial correlation, while the ratios of nugget to sill of the total nitrogen (20.0%), total phosphorus (24.3%), total potassium (11.1%), available nitrogen (11.2%), and available potassium (22.7%) suggested strong spatial correlation. The total phosphorus had the maximum range (1232.7 m), followed by available nitrogen (541.27 m), total nitrogen (468.35 m), total potassium (136.0 m), available potassium (128.7 m), available phosphorus (116.6 m), and soil organic carbon (93.5 m). Soil nutrients had no significant variation with the increase of altitude, but gradually increased from the landslide area, the transition area, to the little-impacted area. The total and available phosphorus contents of the landslide area decreased by 10.3% and 79.7% compared to that of the little-impacted area, respectively. The soil nutrient contents in the transition area accounted for 31.1%-87.2% of that of the little-impacted area, with the nant reason for the spatial variability of surface soil nutrients.

Unravelling the limits to tree height: a major role for water and nutrient trade-offs.

PubMed

Cramer, Michael D

2012-05-01

Competition for light has driven forest trees to grow exceedingly tall, but the lack of a single universal limit to tree height indicates multiple interacting environmental limitations. Because soil nutrient availability is determined by both nutrient concentrations and soil water, water and nutrient availabilities may interact in determining realised nutrient availability and consequently tree height. In SW Australia, which is characterised by nutrient impoverished soils that support some of the world's tallest forests, total [P] and water availability were independently correlated with tree height (r = 0.42 and 0.39, respectively). However, interactions between water availability and each of total [P], pH and [Mg] contributed to a multiple linear regression model of tree height (r = 0.72). A boosted regression tree model showed that maximum tree height was correlated with water availability (24%), followed by soil properties including total P (11%), Mg (10%) and total N (9%), amongst others, and that there was an interaction between water availability and total [P] in determining maximum tree height. These interactions indicated a trade-off between water and P availability in determining maximum tree height in SW Australia. This is enabled by a species assemblage capable of growing tall and surviving (some) disturbances. The mechanism for this trade-off is suggested to be through water enabling mass-flow and diffusive mobility of P, particularly of relatively mobile organic P, although water interactions with microbial activity could also play a role.

Rhizodeposition flux of competitive versus conservative graminoid: contribution of exudates and root lysates as affected by N loading

NASA Astrophysics Data System (ADS)

Kastovska, Eva; Edwards, Keith; Santruckova, Hana

2017-04-01

Carbon allocation pattern represents the plant strategy for growth and nutrient capture. Plants exhibit high plasticity in their allocation pattern and belowground C partitioning in response to changes in the availability of nutrients limiting their production, namely nitrogen (N). Any shift in the belowground C fluxes and partitioning between root production, exudation and other rhizodeposits could affect the soil microbial activity and soil organic matter turnover. We studied the influence of N availability on plant allocation patterns with emphasis on belowground C fluxes of two wetland graminoids, the competitive Glyceria maxima and the conservative Carex acuta. Plants were grown in pots under two levels of N availability. We combined pulse-labeling of plants with 13CO2 to track recent assimilates with estimation of the root death rate calculated from the difference between gross and net root growth rates for assessing the rhizodeposition flux to soil, and the contribution of root exudates and lysates from root turnover. We found that higher N supply enhanced root biomass and, subsequently, the total rhizodeposition. Both species shifted partitioning of belowground C towards higher mass-specific root production and turnover, with lower investments into root exudation. Therefore, the rhizodeposition flux was enriched in root-derived lysates over soluble exudates. Root exudates accounted for 50-70% of the rhizodeposition flux in conditions of low N availability, while it was only 20-40% under high N availability. The N fertilization induced changes in belowground C fluxes were species-specific, with more pronounced changes in the conservative Carex than the competitive Glyceria. In summary, soil N loading enhanced total C rhizodeposition and, simultaneously, the proportion of predominantly more complex root lysates over soluble root exudates, with potential implications for soil organic matter dynamics. Our results further stress the importance of species-specific responses to N loading in predicting total rhizodeposition flux and changes in its quality.

Growth, allocation and tissue chemistry of Picea abies seedlings affected by nutrient supply during the second growing season.

PubMed

Kaakinen, Seija; Jolkkonen, Annika; Iivonen, Sari; Vapaavuori, Elina

2004-06-01

One-year-old Norway spruce (Picea abies (L.) Karst.) seedlings were grown hydroponically in a growth chamber to investigate the effects of low and high nutrient availability (LN; 0.25 mM N and HN; 2.50 mM N) on growth, biomass allocation and chemical composition of needles, stem and roots during the second growing season. Climatic conditions in the growth chamber simulated the mean growing season from May to early October in Flakaliden, northern Sweden. In the latter half of the growing season, biomass allocation changed in response to nutrient availability: increased root growth and decreased shoot growth led to higher root/shoot ratios in LN seedlings than in HN seedlings. At high nutrient availability, total biomass, especially stem biomass, increased, as did total nonstructural carbohydrate and nitrogen contents per seedling. Responses of stem chemistry to nutrient addition differed from those of adult trees of the same provenance. In HN seedlings, concentrations of alpha-cellulose, hemicellulose and lignin decreased in the secondary xylem. Our results illustrate the significance of retranslocation of stored nutrients to support new growth early in the season when root growth and nutrient uptake are still low. We conclude that nutrient availability alters allocation patterns, thereby influencing the success of 2-year-old Norway spruce seedlings at forest planting sites.

Farmers' Perception of Integrated Soil Fertility and Nutrient Management for Sustainable Crop Production: A Study of Rural Areas in Bangladesh

ERIC Educational Resources Information Center

Farouque, Md. Golam; Takeya, Hiroyuki

2007-01-01

This study aimed to determine farmers' perception of integrated soil fertility and nutrient management for sustainable crop production. Integrated soil fertility (ISF) and nutrient management (NM) is an advanced approach to maintain soil fertility and to enhance crop productivity. A total number of 120 farmers from eight villages in four districts…

Maternal–Fetal Nutrient Transport in Pregnancy Pathologies: The Role of the Placenta

PubMed Central

Brett, Kendra Elizabeth; Ferraro, Zachary Michael; Yockell-Lelievre, Julien; Gruslin, Andrée; Adamo, Kristi Bree

2014-01-01

Appropriate in utero growth is essential for offspring development and is a critical contributor to long-term health. Fetal growth is largely dictated by the availability of nutrients in maternal circulation and the ability of these nutrients to be transported into fetal circulation via the placenta. Substrate flux across placental gradients is dependent on the accessibility and activity of nutrient-specific transporters. Changes in the expression and activity of these transporters is implicated in cases of restricted and excessive fetal growth, and may represent a control mechanism by which fetal growth rate attempts to match availability of nutrients in maternal circulation. This review provides an overview of placenta nutrient transport with an emphasis on macro-nutrient transporters. It highlights the changes in expression and activity of these transporters associated with common pregnancy pathologies, including intrauterine growth restriction, macrosomia, diabetes and obesity, as well as the potential impact of maternal diet. Molecular signaling pathways linking maternal nutrient availability and placenta nutrient transport are discussed. How sexual dimorphism affects fetal growth strategies and the placenta’s response to an altered intrauterine environment is considered. Further knowledge in this area may be the first step in the development of targeted interventions to help optimize fetal growth. PMID:25222554

Probiotics for Plants? Growth Promotion by the Entomopathogenic Fungus Beauveria bassiana Depends on Nutrient Availability.

PubMed

Tall, Susanna; Meyling, Nicolai V

2018-03-28

Cultivation of crops requires nutrient supplements which are costly and impact the environment. Furthermore, global demands for increased crop production call for sustainable solutions to increase yield and utilize resources such as nutrients more effectively. Some entomopathogenic fungi are able to promote plant growth, but studies over such effects have been conducted under optimal conditions where nutrients are abundantly available. We studied the effects of Beauveria bassiana (strain GHA) seed treatment on the growth of maize (Zea mays) at high and low nutrient conditions during 6 weeks in greenhouse. As expected, B. bassiana seed treatment increased plant growth, but only at high nutrient conditions. In contrast, the seed treatment did not benefit plant growth at low nutrient conditions where the fungus potentially constituted a sink and tended to reduce plant growth. The occurrence of endophytic B. bassiana in experimental plant tissues was evaluated by PCR after 6 weeks, but B. bassiana was not documented in any of the above-ground plant tissues indicating that the fungus-plant interaction was independent of endophytic establishment. Our results suggest that B. bassiana seed treatment could be used as a growth promoter of maize when nutrients are abundantly available, while the fungus does not provide any growth benefits when nutrients are scarce.

Nutrient-enhanced growth of Cladophora prolifera in harrington sound, bermuda: Eutrophication of a confined, phosphorus-limited marine ecosystem

NASA Astrophysics Data System (ADS)

Lapointe, Brian E.; O'Connell, Julie

1989-04-01

The green alga Cladophora prolifera (Chlorophyta, Cladophorales) has formed widespread blooms in Bermuda's inshore waters during the past 20 years, but, to date, no conclusive evidence links these blooms to nutrient enrichment. This study assessed the nutrient-dependance of productivity of Cladophora collected from Harrington Sound, a confined P-limited marine system where Cladophora first became abundant. Both N- and P-enrichment decreased the doubling time of Cladophora, which ranged from 14 days (with N and P enrichment) to 100 days (without enrichment). Nutrient enrichment also enhanced the light-saturated photosynthetic capacity (i.e. P max) of Cladophora, which ranged from 0·50 mg C g dry wt -1 h -1 (without enrichment) to 1·0 mg C g dry wt -1 h -1 (with enrichment). Tissue C:N, C:P and N:P ratios of unenriched Cladophora were elevated—25, 942, and 49, respectively—levels that suggest limitation by both N and P but primary limitation by P. Pore-waters under Cladophora mats had reduced salinities, elevated concentrations of NH 4, and high N:P ratios (N:P of 85), suggesting that N-rich groundwater seepage enriches Cladophora mats. The alkaline phosphatase capacity of Cladophora was high compared to other macroalgae in Harrington Sound, and its capacity was enhanced by N-enrichment and suppressed by P-enrichment. Because the productivity of Cladophora is nutrient-limited in shallow waters of Harrington Sound, enhanced growth and increased biomass of Cladophora result from cumulative seepage of N-rich groundwaters coupled with efficient utilization and recycling of dissolved organo-phosphorus compounds.

Nitrate, ascorbic acid, mineral and antioxidant activities of Cosmos caudatus in response to organic and mineral-based fertilizer rates.

PubMed

Hassan, Siti Aishah; Mijin, Salumiah; Yusoff, Umi Kalsom; Ding, Phebe; Wahab, Puteri Edaroyati Megat

2012-06-28

The source and quantity of nutrients available to plants can affect the quality of leafy herbs. A study was conducted to compare quality of Cosmos caudatus in response to rates of organic and mineral-based fertilizers. Organic based fertilizer GOBI (8% N:8% P₂O₅:8% K₂O) and inorganic fertilizer (15% N, 15% P₂O₅, 15% K₂O) were evaluated based on N element rates at 0, 30, 60, 90, 120 kg h⁻¹. Application of organic based fertilizer reduced nitrate, improved vitamin C, antioxidant activity as well as nitrogen and calcium nutrients content. Antioxidant activity and chlorophyll content were significantly higher with increased fertilizer application. Fertilization appeared to enhance vitamin C content, however for the maximum ascorbic acid content, regardless of fertilizer sources, plants did not require high amounts of fertilizer.

7 CFR 3430.201 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-01-01

... responses and tolerances; (iii) Nutrient management, including plant nutrient uptake efficiency; (iv) Pest and disease management, including resistance to pests and diseases resulting in reduced application management strategies; and (v) Enhanced phytonutrient content. (2) Efforts to identify and address threats...

NUTRIENTS IN WATERSHEDS: DEVELOPING ENHANCED MODELING TOOLS

EPA Science Inventory

Nutrient enrichment is one of the most important stressors causing water-resource impairment. These impairments are causing devastating changes: 1) high nitrate concentrations have rendered the groundwaters and reservoirs in many regions impotable -- especially in the rural area...

Reducing Nutrients to San Francisco Bay through Additional Wastewater Sidestream Treatment Project

EPA Pesticide Factsheets

Information about the SFBWQP Reducing Nutrients to San Francisco Bay Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

Method and apparatus for determining nutrient stimulation of biological processes

DOEpatents

Colwell, F.S.; Geesey, G.G.; Gillis, R.J.; Lehman, R.M.

1997-11-11

A method and apparatus is described for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for said microorganisms in said sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure differences in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses. 5 figs.

Method and apparatus for determining nutrient stimulation of biological processes

DOEpatents

Colwell, Frederick S.; Geesey, Gill G.; Gillis, Richard J.; Lehman, R. Michael

1999-01-01

A method and apparatus for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for said microorganisms in said sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure difference in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses.

Method and apparatus for determining nutrient stimulation of biological processes

DOEpatents

Colwell, F.S.; Geesey, G.G.; Gillis, R.J.; Lehman, R.M.

1999-07-13

A method and apparatus are disclosed for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for microorganisms in the sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure difference in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses. 5 figs.

Method and apparatus for determining nutrient stimulation of biological processes

DOEpatents

Colwell, Frederick S.; Geesey, Gill G.; Gillis, Richard J.; Lehman, R. Michael

1997-01-01

A method and apparatus for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for said microorganisms in said sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure differences in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses.

Dispersion/dilution enhances phytoplankton blooms in low-nutrient waters

NASA Astrophysics Data System (ADS)

Lehahn, Yoav; Koren, Ilan; Sharoni, Shlomit; D'Ovidio, Francesco; Vardi, Assaf; Boss, Emmanuel

2017-03-01

Spatial characteristics of phytoplankton blooms often reflect the horizontal transport properties of the oceanic turbulent flow in which they are embedded. Classically, bloom response to horizontal stirring is regarded in terms of generation of patchiness following large-scale bloom initiation. Here, using satellite observations from the North Pacific Subtropical Gyre and a simple ecosystem model, we show that the opposite scenario of turbulence dispersing and diluting fine-scale (~1-100 km) nutrient-enriched water patches has the critical effect of regulating the dynamics of nutrients-phytoplankton-zooplankton ecosystems and enhancing accumulation of photosynthetic biomass in low-nutrient oceanic environments. A key factor in determining ecological and biogeochemical consequences of turbulent stirring is the horizontal dilution rate, which depends on the effective eddy diffusivity and surface area of the enriched patches. Implementation of the notion of horizontal dilution rate explains quantitatively plankton response to turbulence and improves our ability to represent ecological and biogeochemical processes in oligotrophic oceans.

Effects of nutrient availabiiity on biomass allocation as well as constitutive and rapid induced herbivore resistance in poplar

Treesearch

Carolyn Glynn; Daniel A. Herms; Marie Egawa; Robert Hansen; William J. Mattson

2003-01-01

Many studies have examined effects of nutrient availability on constitutive herbivore resistance of plants, but few have addressed effects on expression of rapid induced resistance (RIR). We quantified effects of two levels of nutrient availability on growth, biomass allocation, photosynthesis, and constitutive secondary metabolism of black poplar (>i>Populus...

The influence of nutrient and water availability on carbohydrate storage in loblolly pine

Treesearch

K.H. Ludovici; H.L. Allen; T.J. Albaugh; P.M. Dougherty

2002-01-01

We quantified the effects of nutrient and water availability on monthly whole-tree carbohydrate budgets and determined allocation patterns of storage carbohydrates in loblolly pine (Pinus taeda) to test site resource impacts on internal carbon (C) storage. A factorial combination of two nutrient and two irrigation treatments were imposed on a 7-year...

[Spatial variability of soil nutrients based on geostatistics combined with GIS--a case study in Zunghua City of Hebei Province].

PubMed

Guo, X; Fu, B; Ma, K; Chen, L

2000-08-01

Geostatistics combined with GIS was applied to analyze the spatial variability of soil nutrients in topsoil (0-20 cm) in Zunghua City of Hebei Province. GIS can integrate attribute data with geographical data of system variables, which makes the application of geostatistics technique for large spatial scale more convenient. Soil nutrient data in this study included available N (alkaline hydrolyzing nitrogen), total N, available K, available P and organic matter. The results showed that the semivariograms of soil nutrients were best described by spherical model, except for that of available K, which was best fitted by complex structure of exponential model and linear with sill model. The spatial variability of available K was mainly produced by structural factor, while that of available N, total N, available P and organic matter was primarily caused by random factor. However, their spatial heterogeneity degree was different: the degree of total N and organic matter was higher, and that of available P and available N was lower. The results also indicated that the spatial correlation of the five tested soil nutrients at this large scale was moderately dependent. The ranges of available N and available P were almost same, which were 5 km and 5.5 km, respectively. The range of total N was up to 18 km, and that of organic matter was 8.5 km. For available K, the spatial variability scale primarily expressed exponential model between 0-3.5 km, but linear with sill model between 3.5-25.5 km. In addition, five soil nutrients exhibited different isotropic ranges. Available N and available P were isotropic through the whole research range (0-28 km). The isotropic range of available K was 0-8 km, and that of total N and organic matter was 0-10 km.

The availability and accessibility of nutrition information in fast food outlets in five states post-menu labelling legislation in New South Wales.

PubMed

Wellard, Lyndal; Havill, Michelle; Hughes, Clare; Watson, Wendy L; Chapman, Kathy

2015-12-01

1) Explore the availability and accessibility of fast food energy and nutrient information post-NSW menu labelling legislation in states with and without menu labelling legislation. 2) Determine whether availability and accessibility differed compared with pre-menu labelling legislation in NSW. We visited 210 outlets of the five largest fast food chains in five Australian states to observe the availability and accessibility of energy and nutrient information. Results were compared with 197 outlets surveyed pre-menu labelling. Most outlets (95%) provided energy values, half provided nutrient values and 3% provided information for all menu items. The total amount of information available increased post-NSW menu labelling implementation (473 versus 178 pre-implementation, p<0.001); however, fewer outlets provided nutrient values (26% versus 97% pre-implementation, p<0.001). Fast food chains surveyed had voluntarily introduced menu labelling nationally. However, more nutrient information was available in-store in 2010, showing that fast food chains are able to provide comprehensive nutrition information, yet they have stopped doing so. Menu labelling legislation should compel fast food chains to provide accessible nutrition information including nutrient values in addition to energy for all menu items in-store. Additionally, public education campaigns are needed to ensure customers can use menu labelling. © 2015 Public Health Association of Australia.

Tailoring biocontrol to maximize top-down effects: on the importance of underlying site fertility.

PubMed

Hovick, Stephen M; Carson, Walter P

2015-01-01

The degree to which biocontrol agents impact invasive plants varies widely across landscapes, often for unknown reasons. Understanding this variability can help optimize invasive species management while also informing our understanding of trophic linkages. To address these issues, we tested three hypotheses with contrasting predictions regarding the likelihood of biocontrol success. (1) The biocontrol effort hypothesis: invasive populations are regulated primarily by top-down effects, predicting that increased biocontrol efforts alone (e.g., more individuals of a given biocontrol agent or more time since agent release) will enhance biocontrol success. (2) The relative fertility hypothesis: invasive populations are regulated primarily by bottom-up effects, predicting that nutrient enrichment will increase dominance by invasives and thus reduce biocontrol success, regardless of biocontrol efforts. (3) The fertility-dependent biocontrol effort hypothesis: top-down effects will only regulate invasive populations if bottom-up effects are weak. It predicts that greater biocontrol efforts will increase biocontrol success, but only in low-nutrient sites. To test these hypotheses, we surveyed 46 sites across three states with prior releases of Galerucella beetles, the most common biocontrol agents used against invasive purple loosestrife (Lythrum salicaria). We found strong support for the fertility-dependent biocontrol effort hypothesis, as biocontrol success occurred most often with greater biocontrol efforts, but only in low-fertility sites. This result held for early stage metrics of biocontrol success (higher Galerucella abundance) and ultimate biocontrol outcomes (decreased loosestrife plant size and abundance). Presence of the invasive grass Phalaris arundinacea was also inversely related to loosestrife abundance, suggesting that biocontrol-based reductions in loosestrife made secondary invasion by P. arundinacea more likely. Our data suggest that low-nutrient sites be prioritized for loosestrife biocontrol and that future monitoring account for variation in site fertility or work to mitigate it. We introduce a new framework that integrates our findings with conflicting patterns previously reported from other biocontrol systems, proposing a unimodal relationship whereby nutrient availability enhances biocontrol success in low-nutrient sites but hampers it in high-nutrient sites. Our results represent one of the first examples of biocontrol success depending on site fertility, which has the potential to inform biocontrol-based management decisions across entire regions and among contrasting systems.

Selection of Optimal Auxiliary Soil Nutrient Variables for Cokriging Interpolation

PubMed Central

Song, Genxin; Zhang, Jing; Wang, Ke

2014-01-01

In order to explore the selection of the best auxiliary variables (BAVs) when using the Cokriging method for soil attribute interpolation, this paper investigated the selection of BAVs from terrain parameters, soil trace elements, and soil nutrient attributes when applying Cokriging interpolation to soil nutrients (organic matter, total N, available P, and available K). In total, 670 soil samples were collected in Fuyang, and the nutrient and trace element attributes of the soil samples were determined. Based on the spatial autocorrelation of soil attributes, the Digital Elevation Model (DEM) data for Fuyang was combined to explore the coordinate relationship among terrain parameters, trace elements, and soil nutrient attributes. Variables with a high correlation to soil nutrient attributes were selected as BAVs for Cokriging interpolation of soil nutrients, and variables with poor correlation were selected as poor auxiliary variables (PAVs). The results of Cokriging interpolations using BAVs and PAVs were then compared. The results indicated that Cokriging interpolation with BAVs yielded more accurate results than Cokriging interpolation with PAVs (the mean absolute error of BAV interpolation results for organic matter, total N, available P, and available K were 0.020, 0.002, 7.616, and 12.4702, respectively, and the mean absolute error of PAV interpolation results were 0.052, 0.037, 15.619, and 0.037, respectively). The results indicated that Cokriging interpolation with BAVs can significantly improve the accuracy of Cokriging interpolation for soil nutrient attributes. This study provides meaningful guidance and reference for the selection of auxiliary parameters for the application of Cokriging interpolation to soil nutrient attributes. PMID:24927129

Distributions of Competing Container Mosquitoes Depend on Detritus Types, Nutrient Ratios, and Food Availability

PubMed Central

Murrell, Ebony G.; Damal, Kavitha; Lounibos, L. P.; Juliano, Steven A.

2012-01-01

Coexistence of competitors may result if resources are sufficiently abundant to render competition unimportant, or if species differ in resource requirements. Detritus type has been shown to affect interspecific competitive outcomes between Aedes albopictus (Skuse) and Aedes aegypti (L.) larvae under controlled conditions. We assessed the relationships among spatial distributions of detritus types, nutrients, and aquatic larvae of these species in nature. We collected mosquitoes, water, and detritus from artificial containers across 24 Florida cemeteries that varied in relative abundances of Ae. aegypti and Ae. albopictus.We measured nutrient content of fine particulate organic matter in water samples as total N, P, and C and ratios of these nutrients. We quantified food availability via a bioassay, raising individual Aedes larvae in the laboratory in standard volumes of field-collected, particulate-containing water from each cemetery. Quantities of detritus types collected in standard containers were significant predictors of nutrients and nutrient ratios. Nutrient abundances were significant predictors of relative abundance of Ae. aegypti, and of larval survival and development by both species in the bioassay. Survival and development of larvae reared in particulate-containing water from sites decreased with decreasing relative abundance of Ae. aegypti. These data suggest that N, P, and C availabilities are determined by detritus inputs to containers and that these nutrients in turn determine the feeding environment encountered by larvae, the intensity of interspecific competition among larvae, and subsequent relative abundances of species at sites. Detritus inputs, nutrients, and food availability thus seem to contribute to distributions of Ae. aegypti and Ae. albopictus in cemetery containers throughout Florida. PMID:22707761

Arbuscular mycorrhizas enhance nutrient uptake in different wheat genotypes at high salinity levels under field and greenhouse conditions.

PubMed

Mardukhi, Baran; Rejali, Farhad; Daei, Gudarz; Ardakani, Mohammad Reza; Malakouti, Mohammad Javad; Miransari, Mohammad

2011-07-01

Since most experiments regarding the symbiosis between arbuscular mycorrhizal (AM) fungi and their host plants under salinity stress have been performed only under greenhouse conditions, this research work was also conducted under field conditions. The effects of three AM species including Glomus mosseae, G. etunicatum and G. intraradices on the nutrient uptake of different wheat cultivars (including Roshan, Kavir and Tabasi) under field and greenhouse (including Chamran and Line 9) conditions were determined. At field harvest, the concentrations of N, Ca, Mg, Fe, Cu, and Mn, and at greenhouse harvest, plant growth, root colonization and concentrations of different nutrients including N, K, P, Ca, Mg, Mn, Cu, Fe, Zn, Na and Cl were determined. The effects of wheat cultivars on the concentrations of N, Ca, and Mn, and of all nutrients were significant at field and greenhouse conditions, respectively. In both experiments, AM fungi significantly enhanced the concentrations of all nutrients including N, K, P, Ca, Mg, Mn, Cu, Fe, Zn, Na and Cl. The synergistic and enhancing effects of co-inoculation of AM species on plant growth and the inhibiting effect of AM species on Na(+) rather than on Cl(-) uptake under salinity are also among the important findings of this research work. Copyright © 2011 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Growth of mature boreal Norway spruce was not affected by elevated [CO(2)] and/or air temperature unless nutrient availability was improved.

PubMed

Sigurdsson, Bjarni D; Medhurst, Jane L; Wallin, Göran; Eggertsson, Olafur; Linder, Sune

2013-11-01

The growth responses of mature Norway spruce (Picea abies (L.) Karst.) trees exposed to elevated [CO(2)] (CE; 670-700 ppm) and long-term optimized nutrient availability or elevated air temperature (TE; ±3.9 °C) were studied in situ in northern Sweden in two 3 year field experiments using 12 whole-tree chambers in ca. 40-year-old forest. The first experiment (Exp. I) studied the interactions between CE and nutrient availability and the second (Exp. II) between CE and TE. It should be noted that only air temperature was elevated in Exp. II, while soil temperature was maintained close to ambient. In Exp. I, CE significantly increased the mean annual height increment, stem volume and biomass increment during the treatment period (25, 28, and 22%, respectively) when nutrients were supplied. There was, however, no significant positive CE effect found at the low natural nutrient availability. In Exp. II, which was conducted at the natural site fertility, neither CE nor TE significantly affected height or stem increment. It is concluded that the low nutrient availability (mainly nitrogen) in the boreal forests is likely to restrict their response to the continuous rise in [CO(2)] and/or TE.

Water-quality assessment of the Lower Susquehanna River Basin, Pennsylvania and Maryland; sources, characteristics, analysis and limitations of nutrient and suspended-sediment data, 1975-90

USGS Publications Warehouse

Hainly, R.A.; Loper, C.A.

1997-01-01

This report describes analyses of available information on nutrients and suspended sediment collected in the Lower Susquehanna River Basin during water years 1975-90. Most of the analyses were applied to data collected during water years 1980-89. The report describes the spatial and temporal availability of nutrient and suspended-sediment data and presents a preliminary concept of the spatial and temporal patterns of concentrations and loads within the basin. Where data were available, total and dissolved forms of nitrogen and phosphorus species from precipitation, surface water, ground water, and springwater, and bottom material from streams and reservoirs were evaluated. Suspended-sediment data from streams also were evaluated. The U.S. Geological Survey National Water Information System (NWIS) database was selected as the primary database for the analyses. Precipitation-quality data from the National Atmospheric Deposition Program (NADP) and bottom-material-quality data from the National Uranium Resource Evaluation (NURE) were used to supplement the water-quality data from NWIS. Concentrations of nutrients were available from 3 precipitation sites established for longterm monitoring purposes, 883 wells (854 synoptic areal survey sites and 29 project and research sites), 23 springs (17 synoptic areal survey sites and 6 project and research sites), and 894 bottom-material sites (840 synoptic areal survey sites and 54 project and research sites). Concentrations of nutrients and (or) suspended sediment were available from 128 streams (36 long-term monitoring sites, 51 synoptic areal survey sites, and 41 project and research sites). Concentrations of nutrients and suspended sediment in streams varied temporally and spatially and were related to land use, agricultural practices, and streamflow. A general north-to-south pattern of increasing median nitrate concentrations, from 2 to 5 mg/L, was detected in samples collected in study unit streams. In streams that drain areas dominated by agriculture, concentrations of nutrients and suspended sediment tend to be elevated with respect to those found in areas of other land-use types and are related to the amount of commercial fertilizer and animal manure applied to the area drained by the streams. Animal manure is the dominant source of nitrogen for the streams in the lower, agricultural part of the basin. Concentrations of nutrients in samples from wells varied with season and well depth and were related to hydrogeologic setting. Median concentrations of nitrate were 2.5 and 3.5 mg/L for wells drawing water at depths of 0 to 100 ft and 101 to 200 ft, respectively. The lowest median concentrations for nitrate in ground water from wells were generally found in siliciclastic-bedrock, forested settings of the Ridge and Valley Physiographic Province, and the highest were found in carbonate-bedrock agricultural settings of the Piedmont Physiographic Province. Twenty-five percent of the measurements from wells in carbonate rocks in the Piedmont Physiographic Province exceeded the Pennsylvania drinking-water standard. An estimate of mass balance of nutrient loads within the Lower Susquehanna River Basin was produced by combining the available information on stream loads, atmosphericdeposition loads, commercial-fertilizer applications, animal-manure production, privateseptic-system nonpoint-source loads, and municipal and industrial point-source loads. The percentage of the average annual nitrate load carried in base flow of streams in the study unit ranged from 45 to 76 percent, and the average annual phosphorus load carried in base flow ranged from 20 to 33 percent. Average annual yields of nutrients and suspended sediment from tributary basins are directly related to percentage of drainage area in agriculture and inversely to drainage area. Information required to compute loads of nitrogen and phosphorus were available for all sources except atmospheric deposition, for which only nitrogen data were available. Atmospheric deposition is the dominant source of nitrogen for the mostly forested basins draining the upper half of the study unit. The estimate of total annual nitrogen load to the study unit from precipitation is 98.8 million pounds. Nonpoint and point sources of nutrients were estimated. Nonpoint and point sources combined, including atmospheric deposition, provide a potential annual load of 390 million pounds of nitrogen and 79.5 million pounds of phosphorus. The range of percentages of the estimated nonpoint and point sources that were measured in the stream was 20 to 47 percent for nitrogen and 6 to 14 percent for phosphorus. On the average, the Susquehanna River discharges 141,000 pounds of nitrogen and 7,920 pounds of phosphorus to the Lower Susquehanna River reservoir system each year. About 98 percent of the nitrogen and 60 percent of the phosphorus passes through the reservoir system. Interpretations of available water-quality data and conclusions about the water quality of the Lower Susquehanna River Basin were limited by the scarcity of certain types of water-quality data and current ancillary data. A more complete assessment of the water quality of the basin with respect to nutrients and suspended sediment would be enhanced by the availability of additional data for multiple samples over time from all water environments; samples from streams in the northern and western part of the basin; samples from streams and springs throughout the basin during high base-flow or stormflow conditions; and information on current land-use, and nutrient loading from all types of land-use settings.

Examining the Potential of Forest Residue-Based Amendments for Post-Wildfire Rehabilitation in Colorado, USA

PubMed Central

Minatre, Kerri L.; Pierson, Derek N.; Fegel, Timothy S.; Cotrufo, M. Francesca; Kelly, Eugene F.

2017-01-01

Wildfire is a natural disturbance, though elemental losses and changes that occur during combustion and post-fire erosion can have long-term impacts on soil properties, ecosystem productivity, and watershed condition. Here we evaluate the potential of forest residue-based materials to rehabilitate burned soils. We compare soil nutrient and water availability, and plant recovery after application of 37 t ha−1 of wood mulch, 20 t ha−1 of biochar, and the combination of the two amendments with untreated, burned soils. We also conducted a greenhouse trial to examine how biochar influenced soil nutrient and water content under two wetting regimes. The effects of wood mulch on plant-available soil N and water content were significant and seasonally consistent during the three-year field study. Biochar applied alone had few effects under field conditions, but significantly increased soil pH, Ca, P, and water in the greenhouse. The mulched biochar treatment had the greatest effects on soil N and water availability and increased cover of the most abundant native plant. We found that rehabilitation treatments consisting of forest residue-based products have potential to enhance soil N and water dynamics and plant recovery following severe wildfire and may be justified where erosion risk or water supply protection are crucial. PMID:28321358

Examining the Potential of Forest Residue-Based Amendments for Post-Wildfire Rehabilitation in Colorado, USA.

PubMed

Rhoades, Charles C; Minatre, Kerri L; Pierson, Derek N; Fegel, Timothy S; Cotrufo, M Francesca; Kelly, Eugene F

2017-01-01

Wildfire is a natural disturbance, though elemental losses and changes that occur during combustion and post-fire erosion can have long-term impacts on soil properties, ecosystem productivity, and watershed condition. Here we evaluate the potential of forest residue-based materials to rehabilitate burned soils. We compare soil nutrient and water availability, and plant recovery after application of 37 t ha -1 of wood mulch, 20 t ha -1 of biochar, and the combination of the two amendments with untreated, burned soils. We also conducted a greenhouse trial to examine how biochar influenced soil nutrient and water content under two wetting regimes. The effects of wood mulch on plant-available soil N and water content were significant and seasonally consistent during the three-year field study. Biochar applied alone had few effects under field conditions, but significantly increased soil pH, Ca, P, and water in the greenhouse. The mulched biochar treatment had the greatest effects on soil N and water availability and increased cover of the most abundant native plant. We found that rehabilitation treatments consisting of forest residue-based products have potential to enhance soil N and water dynamics and plant recovery following severe wildfire and may be justified where erosion risk or water supply protection are crucial.

Nutrient resorption and patterns of litter production and decomposition in a Neotropical savanna.

Treesearch

A.R. Kozovits; M.M.C. Bustamante; C.R. Garofalo; S. Bucci; A.C. Franco; G. Goldstein; F. Meinzer

2007-01-01

1. Deposition of nutrients owing to anthropogenic activities has the potential to change nutrient availability in nutrient-limited ecosystems with consequences for plant and ecosystem processes. 2. Species-specific and ecosystem responses to the addition of nutrients were studied in a field experiment conducted in a Savanna (Cerrado sensu stricto)...

Enhanced bioremediation of nutrient-amended, petroleum hydrocarbon-contaminated soils over a cold-climate winter: The rate and extent of hydrocarbon biodegradation and microbial response in a pilot-scale biopile subjected to natural seasonal freeze-thaw temperatures.

PubMed

Kim, Jihun; Lee, Aslan Hwanhwi; Chang, Wonjae

2018-01-15

A pilot-scale biopile field experiment for nutrient-amended petroleum-contaminated fine-grained soils was performed over the winter at a cold-climate site. The rate and extent of hydrocarbon biodegradation and microbial responses were determined and corresponded to the on-site soil phase changes (from unfrozen to partially frozen, deeply frozen, and thawed) associated with natural seasonal freeze-thaw conditions. Treated and untreated biopiles were constructed (~3500kg each) on an open outdoor surface at a remediation facility in Saskatoon, Canada. The treated biopile received N-P-K-based nutrient and humate amendments before seasonal freezing. Real-time field monitoring indicated significant unfrozen water content in the treated and untreated biopiles throughout the freezing period, from the middle of November to early March. Unfrozen water was slightly more available in the treated biopile due to the aqueous nutrient supply. Soil CO 2 production and O 2 consumption in the treated biopile were generally greater than in the untreated biopile. Total removal percentages for F2 (>C10-C16), F3 (>C16-C34), and total petroleum hydrocarbons (TPH) in the treated biopile were 57, 58, and 58%, respectively, of which 26, 39, and 33% were removed during seasonal freezing and early thawing between November to early March. F3 degradation largely occurred during freezing while F2 hydrocarbons were primarily removed during thawing. Biomarker-based hydrocarbon analyses confirmed enhanced biodegradation in the treated biopile during freezing. The soil treatment increased the first-order rate constants for F2, F3, and TPH degradation by a factor of 2 to 7 compared to the untreated biopile. Shifts in bacterial community appeared in both biopiles as the biopile soils seasonally froze and thawed. Increased alkB1 gene copy numbers in the treated biopile, especially in the partially thawed phase during early thawing, suggest extended hydrocarbon biodegradation to the seasonal freeze-thaw season, due to the nutrients supplied prior to seasonal freezing. Copyright © 2017 Elsevier B.V. All rights reserved.

[Changes of soil nutrient contents after prescribed burning of forestland in Heshan City, Guangdong Province].

PubMed

Sun, Yu-xin; Wu, Jian-ping; Zhou, Li-xia; Lin, Yong-biao; Fu, Sheng-lei

2009-03-01

A comparative study was conducted to analyze the changes of soil nutrient contents in Eucalyptus forestland and in shrubland after three years of prescribed burning. In Eucalyptus forestland, soil organic carbon, total nitrogen, available potassium contents and soil pH decreased significantly; soil available phosphorus and exchangeable magnesium contents, net nitrogen mineralization rate and ammonification rate also decreased but showed no significant difference. In shrubland, soil exchangeable calcium content increased significantly, but the contents of other nutrients had no significant change. The main reason of the lower soil net nitrogen mineralization rate in Eucalyptus forest could be the decrease of available substrates and the uptake of larger amount of soil nutrients by the fast growth of Eucalyptus. The soil nutrients in shrubland had a quick restoration rate after burning.

Carbon fluxes in the Arabian Sea: Export versus recycling

NASA Astrophysics Data System (ADS)

Rixen, Tim; Gaye, Birgit; Ramaswamy, Venkitasubramani

2016-04-01

The organic carbon pump strongly influences the exchange of carbon between the ocean and the atmosphere. It is known that it responds to global change but the magnitude and the direction of change are still unpredictable. Sediment trap experiments carried out at various sites in the Arabian Sea between 1986 and 1998 have shown differences in the functioning of the organic carbon pump (OCP). An OCP driven by eukaryotic phytoplankton operated in the upwelling region off Oman and during the spring bloom in the northern Arabian Sea. Cyanobacteria capable of fixing nitrogen seem to dominate the phytoplankton community during all other seasons. The export driven by cyanobacteria was much lower than the export driven by eukaryotic phytoplankton. Productivity and nutrient availability seems to be a main factor controlling fluxes during blooms of eukaryotic phytoplankton. The ballast effect caused by inputs of dust into the ocean and its incorporation into sinking particles seems to be the main factor controlling the export during times when cyanobacteria dominate the phytoplankton community. C/N ratios of organic matter exported from blooms dominated by nitrogen fixing cyanobacteria are enhanced and, furthermore, indicate a more efficient recycling of nutrients at shallower water depth. This implies that the bacterial-driven OCP operates more in a recycling mode that keeps nutrients closer to the euphotic zone whereas the OCP driven by eukaryotic phytoplankton reduces the recycling of nutrients by exporting them into greater water-depth.

Plant growth improvement mediated by nitrate capture in co-composted biochar.

PubMed

Kammann, Claudia I; Schmidt, Hans-Peter; Messerschmidt, Nicole; Linsel, Sebastian; Steffens, Diedrich; Müller, Christoph; Koyro, Hans-Werner; Conte, Pellegrino; Joseph, Stephen; Stephen, Joseph

2015-06-09

Soil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting considerably promoted biochars' positive effects, largely by nitrate (nutrient) capture and delivery. In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a sandy-poor soil amended with 2% (w/w) co-composted biochar (BC(comp)). Conversely, addition of 2% (w/w) untreated biochar (BC(pure)) decreased the biomass to 60% of the control. Growth-promoting (BC(comp)) as well as growth-reducing (BC(pure)) effects were more pronounced at lower nutrient-supply levels. Electro-ultra filtration and sequential biochar-particle washing revealed that co-composted biochar was nutrient-enriched, particularly with the anions nitrate and phosphate. The captured nitrate in BC(comp) was (1) only partly detectable with standard methods, (2) largely protected against leaching, (3) partly plant-available, and (4) did not stimulate N2O emissions. We hypothesize that surface ageing plus non-conventional ion-water bonding in micro- and nano-pores promoted nitrate capture in biochar particles. Amending (N-rich) bio-waste with biochar may enhance its agronomic value and reduce nutrient losses from bio-wastes and agricultural soils.

Does infection tilt the scales? Disease effects on the mass balance of an invertebrate nutrient recycler.

PubMed

Narr, Charlotte F; Frost, Paul C

2015-12-01

While parasites are increasingly recognized as important components of ecosystems, we currently know little about how they alter ecosystem nutrient availability via host-mediated nutrient cycling. We examined whether infection alters the flow of nutrients through hosts and whether such effects depend upon host diet quality. To do so, we compared the mass specific nutrient (i.e., nitrogen and phosphorus) release rates, ingestion rates, and elemental composition of uninfected Daphnia to those infected with a bacterial parasite, P. ramosa. N and P release rates were increased by infection when Daphnia were fed P-poor diets, but we found no effect of infection on the nutrient release of individuals fed P-rich diets. Calculations based on the first law of thermodynamics indicated that infection should increase the nutrient release rates of Daphnia by decreasing nutrient accumulation rates in host tissues. Although we found reduced nutrient accumulation rates in infected Daphnia fed all diets, this reduction did not increase the nutrient release rates of Daphnia fed the P-rich diet because infected Daphnia fed this diet ingested nutrients more slowly than uninfected hosts. Our results thus indicate that parasites can significantly alter the nutrient use of animal consumers, which could affect the availability of nutrients in heavily parasitized environments.

Impact of biomass burning on nutrient deposition to the global ocean

NASA Astrophysics Data System (ADS)

Kanakidou, Maria; Myriokefalitakis, Stelios; Daskalakis, Nikos; Mihalopoulos, Nikolaos; Nenes, Athanasios

2017-04-01

Atmospheric deposition of trace constituents, both of natural and anthropogenic origin, can act as a nutrient source into the open ocean and affect marine ecosystem functioning and subsequently the exchange of CO2 between the atmosphere and the global ocean. Dust is known as a major source of nutrients (Fe and P) into the atmosphere, but only a fraction of these nutrients is released in soluble form that can be assimilated by the ecosystems. Dust is also known to enhance N deposition by interacting with anthropogenic pollutants and neutralisation of part of the acidity of the atmosphere by crustal alkaline species. These nutrients have also primary anthropogenic sources including combustion emissions. The global atmospheric N [1], Fe [2] and P [3] cycles have been parameterized in the global 3-D chemical transport model TM4-ECPL, accounting for inorganic and organic forms of these nutrients, for all natural and anthropogenic sources of these nutrients including biomass burning, as well as for the link between the soluble forms of Fe and P atmospheric deposition and atmospheric acidity. The impact of atmospheric acidity on nutrient solubility has been parameterised based on experimental findings and the model results have been evaluated by extensive comparison with available observations. In the present study we isolate the significant impact of biomass burning emissions on these nutrients deposition by comparing global simulations that consider or neglect biomass burning emissions. The investigated impact integrates changes in the emissions of the nutrients as well as in atmospheric oxidants and acidity and thus in atmospheric processing and secondary sources of these nutrients. The results are presented and thoroughly discussed. References [1] Kanakidou M, S. Myriokefalitakis, N. Daskalakis, G. Fanourgakis, A. Nenes, A. Baker, K. Tsigaridis, N. Mihalopoulos, Past, Present and Future Atmospheric Nitrogen Deposition, Journal of the Atmospheric Sciences (JAS-D-15-0278) Vol 73, 2039-2047, 2016. [2] Myriokefalitakis,S., Daskalakis,N., Mihalopoulos,N., Baker, A.R., Nenes, A., and Kanakidou,M.: Changes in dissolved iron deposition to the oceans driven by human activity: a 3-D global modelling study, Biogeosciences, 12, 3973-3992, 2015. [3] Myriokefalitakis S., Nenes A., Baker A.R., Mihalopoulos N., Kanakidou M.: Bioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modelling study, Biogeosciences, 13, 6519-6543, 2016.

Nutrients removal and substrate enzyme activities in vertical subsurface flow constructed wetlands for mariculture wastewater treatment: Effects of ammonia nitrogen loading rates and salinity levels.

PubMed

Li, Meng; Liang, Zhenlin; Callier, Myriam D; Roque d'orbcastel, Emmanuelle; Sun, Guoxiang; Ma, Xiaona; Li, Xian; Wang, Shunkui; Liu, Ying; Song, Xiefa

2018-06-01

This study aims to investigate the effects of ammonia nitrogen loading rates and salinity levels on nutrients removal rates and substrate enzyme activities of constructed wetland (CW) microcosms planted with Salicornia bigelovii treating mariculture wastewater. Activities of urease (UA), dehydrogenase (DA), protease (PrA) and phosphatase (PA) were considered. Using principal component analysis (PCA), nutrient removal index (NRI) and enzyme activity index (EAI) were developed to evaluate the effects. The results revealed that increasing ammonia nitrogen loading rates had positive effects on nitrogen removal rates (i.e. NH 4 -N and DIN) and enhanced substrate enzyme activities. Compared with low salinity (i.e. 15 and 22), high salinity levels (i.e. 29 and 36) enhanced nutrients removal rates, DA and UA, but weaken PA and PrA. In conclusion, CW microcosms with Salicornia bigelovii can be used for the removal of nutrients under a range of ammonia nitrogen loadings and high salinity levels. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhanced dissolved lipid production as a response to the sea surface warming

NASA Astrophysics Data System (ADS)

Novak, Tihana; Godrijan, Jelena; Pfannkuchen, Daniela Marić; Djakovac, Tamara; Mlakar, Marina; Baricevic, Ana; Tanković, Mirta Smodlaka; Gašparović, Blaženka

2018-04-01

The temperature increase in oceans reflects on marine ecosystem functioning and surely has consequences on the marine carbon cycle and carbon sequestration. In this study, we examined dissolved lipid, lipid classes and dissolved organic carbon (DOC) production in the northern Adriatic Sea, isolated diatom Chaetoceros pseudocurvisetus batch cultures grown in a wide temperature range (10-30 °C) and in contrasting nutrient regimes, phosphorus (P)-depleted and P-replete conditions. Additionally, lipids and DOC were analyzed in the northern Adriatic (NA) in two stations characterized with different P availability, occupied from February to August 2010 that covered a temperature range from 9.3 to 31.1 °C. To gain insight into factors governing lipid and lipid classes' production in the NA, apart from temperature (T), Chlorophyll a, phytoplankton community abundance and structure, nutrient concentrations were measured together with hydrographic parameters. We found enhanced accumulation of dissolved lipids, particulary glycolipids, with increasing T, especially during the highest in situ temperature. The effect of T on enhanced dissolved lipid release is much more pronounced under P-deplete conditions indicating that oligotrophic regions might be more vulnerable to T rise. Temperature between 25 and 30 °C is a threshold T range for C. pseudocurvisetus, at which a significant part of lipid production is directed toward the dissolved phase. Unlike monocultures, there are multiple factors influencing produced lipid composition, distribution and cycling in the NA that may counteract the T influence. The possible role of enhanced dissolved lipid concentration for carbon sequestration at elevated T is discussed. On the one hand, lipids are buoyant and do not sink, which enhances their retention at the surface layer. In addition, they are surface active, and therefore prone to adsorb on sinking particles, contributing to the C sequestration.

Wind driven nutrient and subsurface chlorophyll-a enhancement in the Bay of La Paz, Gulf of California

NASA Astrophysics Data System (ADS)

Coria-Monter, Erik; Monreal-Gómez, María Adela; Salas de León, David Alberto; Durán-Campos, Elizabeth; Merino-Ibarra, Martín

2017-09-01

Nutrient and chlorophyll-a distributions in the Bay of La Paz, Gulf of California, Mexico were analyzed during the late spring of 2004 to assess their relations to hydrography and circulation patterns. The results show the presence of both Gulf of California Water and Subtropical Subsurface Water. Water circulation was dominated by wind stress driven cyclonic circulation along f / H contours (f is planetary vorticity and H is depth), and upwelling resulting from the divergence shows a vertical velocity of ∼0.4 m d-1. Nutrient concentrations were higher in the center of the cyclonic pattern, where a rise in the nutricline contributed nutrients to the euphotic layer as a result of Ekman pumping. The vertical section showed the presence of a chlorophyll-a maximum at the thermocline shoaling to a depth of only 12 m. Along the surface, two peaks of chlorophyll-a were observed, one at Boca Grande and another off San Juan de la Costa, associated with upwelling and mixing derived from current interactions with abrupt topographies. The chlorophyll-a maximum increased from 0.8 mg m-3 in the external part of the cyclonic pattern to 2.0 mg m-3 in its center. The vertically integrated chlorophyll-a concentrations followed a similar pattern, rising from 10 to 20 mg m-2 and reaching their highest values in the center of the cyclonic circulation pattern. A schematic model was developed to describe processes that occur in late spring: the wind stress driven cyclonic structure promotes upward nutrient flux, which in turn drives an enhancement of chlorophyll-a. Upwelling was found to be the main mechanism of fertilization responsible for the enhancement of productivity levels by means of nutrient transport into the euphotic zone during spring. Other chlorophyll enhancement areas point to the occurrence of additional fertilization processes that may derive from interactions between cyclonic circulation patterns and the topography off of San Juan de la Costa, where phosphate mining occurs.

Nutrient availability in rangeland soils: influence of prescribed burning, herbaceous vegetation removal, overseeding with Bromus tectorum, season, and elevation

Treesearch

R. R. Blank; J. Chambers; B. Roundy; A. Whittaker

2007-01-01

Soil nutrient availability influences plant invasions. Resin capsules were used to examine soil nutrient bioavailability along 2 sagebrush-grassland elevation transects in the east Tintic Range (Utah) and Shoshone Range (Nevada). In the fall of 2001, treatments were applied to 3 replicate plots at each site, which included prescribed burning, herbaceous vegetation...

Stormwater harvesting for irrigation purposes: an investigation of chemical quality of water recycled in pervious pavement system.

PubMed

Nnadi, Ernest O; Newman, Alan P; Coupe, Stephen J; Mbanaso, Fredrick U

2015-01-01

Most available water resources in the world are used for agricultural irrigation. Whilst this level of water use is expected to increase due to rising world population and land use, available water resources are expected to become limited due to climate change and uneven rainfall distribution. Recycled stormwater has the potential to be used as an alternative source of irrigation water and part of sustainable water management strategy. This paper reports on a study to investigate whether a sustainable urban drainage system (SUDS) technique, known as the pervious pavements system (PPS) has the capability to recycle water that meets irrigation water quality standard. Furthermore, the experiment provided information on the impact of hydrocarbon (which was applied to simulate oil dripping from parked vehicles onto PPS), leaching of nutrients from different layers of the PPS and effects of nutrients (applied to enhance bioremediation) on the stormwater recycling efficiency of the PPS. A weekly dose of 6.23 × 10(-3) L of lubricating oil and single dose of 17.06 g of polymer coated controlled-release fertilizer granules were applied to the series of 710 mm × 360 mm model pervious pavement structure except the controls. Rainfall intensity of 7.4 mm/h was applied to the test models at the rate of 3 events per week. Analysis of the recycled water showed that PPS has the capability to recycle stormwater to a quality that meets the chemical standards for use in agricultural irrigation irrespective of the type of sub-base used. There is a potential benefit of nutrient availability in recycled water for plants, but care should be taken not to dispose of this water in natural water courses as it might result in eutrophication problems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Phosphorus-mobilization ecosystem engineering: the roles of cluster roots and carboxylate exudation in young P-limited ecosystems

PubMed Central

Lambers, Hans; Bishop, John G.; Hopper, Stephen D.; Laliberté, Etienne; Zúñiga-Feest, Alejandra

2012-01-01

Background Carboxylate-releasing cluster roots of Proteaceae play a key role in acquiring phosphorus (P) from ancient nutrient-impoverished soils in Australia. However, cluster roots are also found in Proteaceae on young, P-rich soils in Chile where they allow P acquisition from soils that strongly sorb P. Scope Unlike Proteaceae in Australia that tend to proficiently remobilize P from senescent leaves, Chilean Proteaceae produce leaf litter rich in P. Consequently, they may act as ecosystem engineers, providing P for plants without specialized roots to access sorbed P. We propose a similar ecosystem-engineering role for species that release large amounts of carboxylates in other relatively young, strongly P-sorbing substrates, e.g. young acidic volcanic deposits and calcareous dunes. Many of these species also fix atmospheric nitrogen and release nutrient-rich litter, but their role as ecosystem engineers is commonly ascribed only to their diazotrophic nature. Conclusions We propose that the P-mobilizing capacity of Proteaceae on young soils, which contain an abundance of P, but where P is poorly available, in combination with inefficient nutrient remobilization from senescing leaves allows these species to function as ecosystem engineers. We suggest that diazotrophic species that colonize young soils with strong P-sorption potential should be considered for their positive effect on P availability, as well as their widely accepted role in nitrogen fixation. Their P-mobilizing activity possibly also enhances their nitrogen-fixing capacity. These diazotrophic species may therefore facilitate the establishment and growth of species with less-efficient P-uptake strategies on more-developed soils with low P availability through similar mechanisms. We argue that the significance of cluster roots and high carboxylate exudation in the development of young ecosystems is probably far more important than has been envisaged thus far. PMID:22700940

Phosphorus-mobilization ecosystem engineering: the roles of cluster roots and carboxylate exudation in young P-limited ecosystems.

PubMed

Lambers, Hans; Bishop, John G; Hopper, Stephen D; Laliberté, Etienne; Zúñiga-Feest, Alejandra

2012-07-01

Carboxylate-releasing cluster roots of Proteaceae play a key role in acquiring phosphorus (P) from ancient nutrient-impoverished soils in Australia. However, cluster roots are also found in Proteaceae on young, P-rich soils in Chile where they allow P acquisition from soils that strongly sorb P. Unlike Proteaceae in Australia that tend to proficiently remobilize P from senescent leaves, Chilean Proteaceae produce leaf litter rich in P. Consequently, they may act as ecosystem engineers, providing P for plants without specialized roots to access sorbed P. We propose a similar ecosystem-engineering role for species that release large amounts of carboxylates in other relatively young, strongly P-sorbing substrates, e.g. young acidic volcanic deposits and calcareous dunes. Many of these species also fix atmospheric nitrogen and release nutrient-rich litter, but their role as ecosystem engineers is commonly ascribed only to their diazotrophic nature. We propose that the P-mobilizing capacity of Proteaceae on young soils, which contain an abundance of P, but where P is poorly available, in combination with inefficient nutrient remobilization from senescing leaves allows these species to function as ecosystem engineers. We suggest that diazotrophic species that colonize young soils with strong P-sorption potential should be considered for their positive effect on P availability, as well as their widely accepted role in nitrogen fixation. Their P-mobilizing activity possibly also enhances their nitrogen-fixing capacity. These diazotrophic species may therefore facilitate the establishment and growth of species with less-efficient P-uptake strategies on more-developed soils with low P availability through similar mechanisms. We argue that the significance of cluster roots and high carboxylate exudation in the development of young ecosystems is probably far more important than has been envisaged thus far.

Controls of bedrock geochemistry on soil and plant nutrients in Southeastern Utah

USGS Publications Warehouse

Neff, J.C.; Reynolds, R.; Sanford, R.L.; Fernandez, D.; Lamothe, P.

2006-01-01

The cold deserts of the Colorado Plateau contain numerous geologically and geochemically distinct sedimentary bedrock types. In the area near Canyonlands National Park in Southeastern Utah, geochemical variation in geologic substrates is related to the depositional environment with higher concentrations of Fe, Al, P, K, and Mg in sediments deposited in alluvial or marine environments and lower concentrations in bedrock derived from eolian sand dunes. Availability of soil nutrients to vegetation is also controlled by the formation of secondary minerals, particularly for P and Ca availability, which, in some geologic settings, appears closely related to variation of CaCO3 and Ca-phosphates in soils. However, the results of this study also indicate that P content is related to bedrock and soil Fe and Al content suggesting that the deposition history of the bedrock and the presence of P-bearing Fe and Al minerals, is important to contemporary P cycling in this region. The relation between bedrock type and exchangeable Mg and K is less clear-cut, despite large variation in bedrock concentrations of these elements. We examined soil nutrient concentrations and foliar nutrient concentration of grasses, shrubs, conifers, and forbs in four geochemically distinct field sites. All four of the functional plant groups had similar proportional responses to variation in soil nutrient availability despite large absolute differences in foliar nutrient concentrations and stoichiometry across species. Foliar P concentration (normalized to N) in particular showed relatively small variation across different geochemical settings despite large variation in soil P availability in these study sites. The limited foliar variation in bedrock-derived nutrients suggests that the dominant plant species in this dryland setting have a remarkably strong capacity to maintain foliar chemistry ratios despite large underlying differences in soil nutrient availability. ?? 2006 Springer Science+Business Media, Inc.

High Nutrient Transport and Cycling Potential Revealed in the Microbial Metagenome of Australian Sea Lion (Neophoca cinerea) Faeces

PubMed Central

Lavery, Trish J.; Roudnew, Ben; Seymour, Justin; Mitchell, James G.; Jeffries, Thomas

2012-01-01

Metagenomic analysis was used to examine the taxonomic diversity and metabolic potential of an Australian sea lion (Neophoca cinerea) gut microbiome. Bacteria comprised 98% of classifiable sequences and of these matches to Firmicutes (80%) were dominant, with Proteobacteria and Actinobacteria representing 8% and 2% of matches respectively. The relative proportion of Firmicutes (80%) to Bacteriodetes (2%) is similar to that in previous studies of obese humans and obese mice, suggesting the gut microbiome may confer a predisposition towards the excess body fat that is needed for thermoregulation within the cold oceanic habitats foraged by Australian sea lions. Core metabolic functions, including carbohydrate utilisation (14%), protein metabolism (9%) and DNA metabolism (7%) dominated the metagenome, but in comparison to human and fish gut microbiomes there was a significantly higher proportion of genes involved in phosphorus metabolism (2.4%) and iron scavenging mechanisms (1%). When sea lions defecate at sea, the relatively high nutrient metabolism potential of bacteria in their faeces may accelerate the dissolution of nutrients from faecal particles, enhancing their persistence in the euphotic zone where they are available to stimulate marine production. PMID:22606263

High nutrient transport and cycling potential revealed in the microbial metagenome of Australian sea lion (Neophoca cinerea) faeces.

PubMed

Lavery, Trish J; Roudnew, Ben; Seymour, Justin; Mitchell, James G; Jeffries, Thomas

2012-01-01

Metagenomic analysis was used to examine the taxonomic diversity and metabolic potential of an Australian sea lion (Neophoca cinerea) gut microbiome. Bacteria comprised 98% of classifiable sequences and of these matches to Firmicutes (80%) were dominant, with Proteobacteria and Actinobacteria representing 8% and 2% of matches respectively. The relative proportion of Firmicutes (80%) to Bacteriodetes (2%) is similar to that in previous studies of obese humans and obese mice, suggesting the gut microbiome may confer a predisposition towards the excess body fat that is needed for thermoregulation within the cold oceanic habitats foraged by Australian sea lions. Core metabolic functions, including carbohydrate utilisation (14%), protein metabolism (9%) and DNA metabolism (7%) dominated the metagenome, but in comparison to human and fish gut microbiomes there was a significantly higher proportion of genes involved in phosphorus metabolism (2.4%) and iron scavenging mechanisms (1%). When sea lions defecate at sea, the relatively high nutrient metabolism potential of bacteria in their faeces may accelerate the dissolution of nutrients from faecal particles, enhancing their persistence in the euphotic zone where they are available to stimulate marine production.

Non Pharmacological Cognitive Enhancers - Current Perspectives.

PubMed

Sachdeva, Ankur; Kumar, Kuldip; Anand, Kuljeet Singh

2015-07-01

Cognition refers to the mental processes involved in thinking, knowing, remembering, judging, and problem solving. Cognitive dysfunctions are an integral part of neuropsychiatric disorders as well as in healthy ageing. Cognitive Enhancers are molecules that help improve aspects of cognition like memory, intelligence, motivation, attention and concentration. Recently, Non Pharmacological Cognitive Enhancers have gained popularity as effective and safe alternative to various established drugs. Many of these Non Pharmacological Cognitive Enhancers seem to be more efficacious compared to currently available Pharmacological Cognitive Enhancers. This review describes and summarizes evidence on various Non Pharmacological Cognitive Enhancers such as physical exercise, sleep, meditation and yoga, spirituality, nutrients, computer training, brain stimulation, and music. We also discuss their role in ageing and different neuro-psychiatric disorders, and current status of Cochrane database recommendations. We searched the Pubmed database for the articles and reviews having the terms 'non pharmacological and cognitive' in the title, published from 2000 till 2014. A total of 11 results displayed, out of which 10 were relevant to the review. These were selected and reviewed. Appropriate cross-references within the articles along with Cochrane reviews were also considered and studied.

Nutritional Supplementation and Meal Timing

NASA Astrophysics Data System (ADS)

Farris, Jim

For the competitive athlete and the serious recreational athlete, nutritional supplementation can have a positive effect on training and on performance. There are many fad supplements on the market, and many that have come and gone. However, two nutrients have withstood the test of time and many tests in research laboratories around the world, and they continue to have positive training- and performance-enhancing effects. Carbohydrates are commonly supplemented to improve energy availability and to replace valuable muscle and liver glycogen stores. Protein supplementation usually is associated with building muscle tissue.

Influence of Anthropogenic Nutrient Additions on Greenhouse Gas Production Rates at Water-soil Interfaces in an Urban Dominated Estuary

NASA Astrophysics Data System (ADS)

Brigham, B. A.; O'Mullan, G. D.; Bird, J. A.

2014-12-01

The tidal Hudson River Estuary (HRE) receives significant inputs of readily dissolvable carbon (C) and nitrogen (N) from incomplete wastewater treatment and sewer overflow during storm events associated with NYC and other urban centers. Nutrient deposition may alter C utilization in the estuarine water column, associated sediments and surrounding wetlands. In these anaerobic systems, we hypothesize that microbial activity is limited by the availability of easily-degradable C (not electron acceptors), which acts as a co-metabolite and provides energy for organic matter decomposition. Sporadic transport of highly C enriched storm derived runoff may substantially enhance greenhouse gas (GHG) production rates through the utilization of stored C pools. To test our hypothesis carbon dioxide (CO2) and methane (CH4) process rates (1) were evaluated from soil cores removed from three distinct HRE wetland sites (Saw Mill Creek, Piermont, and Iona Island Marsh(s)) across a salinity gradient and incubated under varying nutrient treatments. Further, CO2 and CH4 surface water effluxes (2) were quantified from multiple river cruises spanning two years at varying distance from nutrient sources associated with NYC. Incubation experiments from wetland soil core experiments demonstrated that readily degradable C but not inorganic N additions stimulated GHG production (200 - 350 ug C g-1 of dry soil day-1) threefold compared to negative controls. The HRE was found to be both a CO2 and CH4 source under all conditions. The greatest GHG efflux (300 - 3000 nmoles C m-2 day-1) was quantified in mid-channel, tributary, and near shore sites in close proximity to NYC which following precipitation events demonstrated 2-20X increased GHG efflux. These results demonstrate that anthropogenic C additions associated with dense urban centers have the potential to enhance anaerobic microbial degradation of organic matter and subsequent GHG production.

Understanding complexities in coupled dynamics of human-water and food security

NASA Astrophysics Data System (ADS)

Usmani, M.; Kondal, A.; Lin, L.; Colwell, R. R.; Jutla, A.

2017-12-01

Traditional premise of food security is associated with satisfying human hunger by providing sufficient calories to population. Water is the key variable associated with the growth of crops, which is then used as a metric of success for abundance of food across globe. The current framework often negates complex coupled interaction between availability of food nutrients and human well-being (such as productivity, work efficiency, low birth weight, physical and mental growth). Our analysis suggests that 1 in 3 humans suffer from malnutrition across the globe. In last five decades, most of the countries have a decreasing availability trend in at least one of the twenty-three essential food nutrients required for human well-being. We argue that food security can only be achieved if information on use of water for crops and consumption of food must include availability of nutrients for humans. Here, we propose a new concept of "consumptive nutrients" that include constant feedback mechanism between water-human and societal processes- essential for growth, distribution and consumption of food nutrients. Using Ethiopia as a signature rain-fed agricultural region, we will show how decreasing precipitation has led to an increase in crop productivity, but decreased availability of nutrients for humans. This in turn has destabilizing impact on overall regional economy. We will demonstrate why inclusion of nutrients must be a part of discussion for ensuring food security to human population.

Breeding crops for improved mineral nutrition under climate change conditions.

PubMed

Pilbeam, David J

2015-06-01

Improvements in understanding how climate change may influence chemical and physical processes in soils, how this may affect nutrient availability, and how plants may respond to changed availability of nutrients will influence crop breeding programmes. The effects of increased atmospheric CO2 and warmer temperatures, both individually and combined, on soil microbial activity, including mycorrhizas and N-fixing organisms, are evaluated, together with their implications for nutrient availability. Potential changes to plant growth, and the combined effects of soil and plant changes on nutrient uptake, are discussed. The organization of research on the efficient use of macro- and micronutrients by crops under climate change conditions is outlined, including analysis of QTLs for nutrient efficiency. Suggestions for how the information gained can be used in plant breeding programmes are given. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Effects of soil nutrient heterogeneity on intraspecific competition in the invasive, clonal plant Alternanthera philoxeroides.

PubMed

Zhou, Jian; Dong, Bi-Cheng; Alpert, Peter; Li, Hong-Li; Zhang, Ming-Xiang; Lei, Guang-Chun; Yu, Fei-Hai

2012-03-01

Fine-scale, spatial heterogeneity in soil nutrient availability can increase the growth of individual plants, the productivity of plant communities and interspecific competition. If this is due to the ability of plants to concentrate their roots where nutrient levels are high, then nutrient heterogeneity should have little effect on intraspecific competition, especially when there are no genotypic differences between individuals in root plasticity. We tested this hypothesis in a widespread, clonal species in which individual plants are known to respond to nutrient heterogeneity. Plants derived from a single clone of Alternanthera philoxeroides were grown in the greenhouse at low or high density (four or 16 plants per 27·5 × 27·5-cm container) with homogeneous or heterogeneous availability of soil nutrients, keeping total nutrient availability per container constant. After 9 weeks, measurements of size, dry mass and morphology were taken. Plants grew more in the heterogeneous than in the homogeneous treatment, showing that heterogeneity promoted performance; they grew less in the high- than in the low-density treatment, showing that plants competed. There was no interactive effect of nutrient heterogeneity and plant density, supporting the hypothesis that heterogeneity does not affect intraspecific competition in the absence of genotypic differences in plasticity. Treatments did not affect morphological characteristics such as specific leaf area or root/shoot ratio. Results indicate that fine-scale, spatial heterogeneity in the availability of soil nutrients does not increase competition when plants are genetically identical, consistent with the suggestion that effects of heterogeneity on competition depend upon differences in plasticity between individuals. Heterogeneity is only likely to increase the spread of monoclonal, invasive populations such as that of A. philoxeroides in China.

Bottom-up nutrient and top-down fish impacts on insect-mediated mercury flux from aquatic ecosystems.

PubMed

Jones, Taylor A; Chumchal, Matthew M; Drenner, Ray W; Timmins, Gabrielle N; Nowlin, Weston H

2013-03-01

Methyl mercury (MeHg) is one of the most hazardous contaminants in the environment, adversely affecting the health of wildlife and humans. Recent studies have demonstrated that aquatic insects biotransport MeHg and other contaminants to terrestrial consumers, but the factors that regulate the flux of MeHg out of aquatic ecosystems via emergent insects have not been studied. The authors used experimental mesocosms to test the hypothesis that insect emergence and the associated flux of MeHg from aquatic to terrestrial ecosystems is affected by both bottom-up nutrient effects and top-down fish consumer effects. In the present study, nutrient addition led to an increase in MeHg flux primarily by enhancing the biomass of emerging insects whose tissues were contaminated with MeHg, whereas fish decreased MeHg flux primarily by reducing the biomass of emerging insects. Furthermore, the authors found that these factors are interdependent such that the effects of nutrients are more pronounced when fish are absent, and the effects of fish are more pronounced when nutrient concentrations are high. The present study is the first to demonstrate that the flux of MeHg from aquatic to terrestrial ecosystems is strongly enhanced by bottom-up nutrient effects and diminished by top-down consumer effects. Copyright © 2012 SETAC.

Effects of irradiation intensity and pH on nutrients release and solids destruction of waste activated sludge using the microwave-enhanced advanced oxidation process.

PubMed

Chan, W I; Liao, P H; Lo, K V

2010-11-01

Using the microwave-enhanced advanced oxidation process (MW/H2O2-AOP), the pH and irradiation intensity on waste activated sludge samples were investigated to provide insight to the athermal effects on nutrients release, solids destruction, particle size distribution and dewaterability, and to demonstrate their interrelationships. Carbonaceous matters and nutrients released into solution depended on the irradiation intensity and time. Higher irradiation levels tended to be more effective in the solubilization of nutrients and had more pronounced effects in the dewaterability of sludge. In terms of particle size distribution, detectable particles increased in size for treatments in acidic conditions, while the dewaterability of treated sludge was improved. In treatments under neutral and alkaline conditions, the particle size range increased, with more small particles formed, thereby significantly deteriorating the dewaterability of sludge treated in alkaline conditions. The best results for the solubilization of nutrients were in alkaline conditions with high irradiation power, but dewaterability of the sludge was compromised. Sludge treatment with the MW/H2O2-AOP in acidic conditions with high irradiation power yielded the best dewaterable sludge and significant nutrient solubilization; therefore, it is the recommended treatment condition for activated sludge.

A nutrient dependant switch explains mutually exclusive existence of meiosis and mitosis initiation in budding yeast.

PubMed

Wannige, C T; Kulasiri, D; Samarasinghe, S

2014-01-21

Nutrients from living environment are vital for the survival and growth of any organism. Budding yeast diploid cells decide to grow by mitosis type cell division or decide to create unique, stress resistant spores by meiosis type cell division depending on the available nutrient conditions. To gain a molecular systems level understanding of the nutrient dependant switching between meiosis and mitosis initiation in diploid cells of budding yeast, we develop a theoretical model based on ordinary differential equations (ODEs) including the mitosis initiator and its relations to budding yeast meiosis initiation network. Our model accurately and qualitatively predicts the experimentally revealed temporal variations of related proteins under different nutrient conditions as well as the diverse mutant studies related to meiosis and mitosis initiation. Using this model, we show how the meiosis and mitosis initiators form an all-or-none type bistable switch in response to available nutrient level (mainly nitrogen). The transitions to and from meiosis or mitosis initiation states occur via saddle node bifurcation. This bidirectional switch helps the optimal usage of available nutrients and explains the mutually exclusive existence of meiosis and mitosis pathways. © 2013 Elsevier Ltd. All rights reserved.

Synoptic-to-planetary scale wind variability enhances phytoplankton biomass at ocean fronts

NASA Astrophysics Data System (ADS)

Whitt, D. B.; Taylor, J. R.; Lévy, M.

2017-06-01

In nutrient-limited conditions, phytoplankton growth at fronts is enhanced by winds, which drive upward nutrient fluxes via enhanced turbulent mixing and upwelling. Hence, depth-integrated phytoplankton biomass can be 10 times greater at isolated fronts. Using theory and two-dimensional simulations with a coupled physical-biogeochemical ocean model, this paper builds conceptual understanding of the physical processes driving upward nutrient fluxes at fronts forced by unsteady winds with timescales of 4-16 days. The largest vertical nutrient fluxes occur when the surface mixing layer penetrates the nutricline, which fuels phytoplankton in the mixed layer. At a front, mixed layer deepening depends on the magnitude and direction of the wind stress, cross-front variations in buoyancy and velocity at the surface, and potential vorticity at the base of the mixed layer, which itself depends on past wind events. Consequently, mixing layers are deeper and more intermittent in time at fronts than outside fronts. Moreover, mixing can decouple in time from the wind stress, even without other sources of physical variability. Wind-driven upwelling also enhances depth-integrated phytoplankton biomass at fronts; when the mixed layer remains shallower than the nutricline, this results in enhanced subsurface phytoplankton. Oscillatory along-front winds induce both oscillatory and mean upwelling. The mean effect of oscillatory vertical motion is to transiently increase subsurface phytoplankton over days to weeks, whereas slower mean upwelling sustains this increase over weeks to months. Taken together, these results emphasize that wind-driven phytoplankton growth is both spatially and temporally intermittent and depends on a diverse combination of physical processes.

Permafrost carbon—climate feedback is sensitive to deep soil carbon decomposability but not deep soil nitrogen dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koven, Charles D.; Lawrence, David M.; Riley, William J.

Permafrost soils contain enormous amounts of organic carbon whose stability is contingent on remaining frozen. With future warming, these soils may release carbon to the atmosphere and act as a positive feedback to climate change. Significant uncertainty remains on the postthaw carbon dynamics of permafrost-affected ecosystems, in particular since most of the carbon resides at depth where decomposition dynamics may differ from surface soils, and since nitrogen mineralized by decomposition may enhance plant growth. Here we show, using a carbon–nitrogen model that includes permafrost processes forced in an unmitigated warming scenario, that the future carbon balance of the permafrost regionmore » is highly sensitive to the decomposability of deeper carbon, with the net balance ranging from 21 Pg C to 164 Pg C losses by 2300. Increased soil nitrogen mineralization reduces nutrient limitations, but the impact of deep nitrogen on the carbon budget is small due to enhanced nitrogen availability from warming surface soils and seasonal asynchrony between deeper nitrogen availability and plant nitrogen demands. The future carbon balance of this region is projected to hinge more on the rate and extent of permafrost thaw and soil decomposition than on enhanced nitrogen availability for vegetation growth resulting from permafrost thaw.« less

Permafrost carbon—climate feedback is sensitive to deep soil carbon decomposability but not deep soil nitrogen dynamics

DOE PAGES

Koven, Charles D.; Lawrence, David M.; Riley, William J.

2015-03-09

Permafrost soils contain enormous amounts of organic carbon whose stability is contingent on remaining frozen. With future warming, these soils may release carbon to the atmosphere and act as a positive feedback to climate change. Significant uncertainty remains on the postthaw carbon dynamics of permafrost-affected ecosystems, in particular since most of the carbon resides at depth where decomposition dynamics may differ from surface soils, and since nitrogen mineralized by decomposition may enhance plant growth. Here we show, using a carbon–nitrogen model that includes permafrost processes forced in an unmitigated warming scenario, that the future carbon balance of the permafrost regionmore » is highly sensitive to the decomposability of deeper carbon, with the net balance ranging from 21 Pg C to 164 Pg C losses by 2300. Increased soil nitrogen mineralization reduces nutrient limitations, but the impact of deep nitrogen on the carbon budget is small due to enhanced nitrogen availability from warming surface soils and seasonal asynchrony between deeper nitrogen availability and plant nitrogen demands. The future carbon balance of this region is projected to hinge more on the rate and extent of permafrost thaw and soil decomposition than on enhanced nitrogen availability for vegetation growth resulting from permafrost thaw.« less

Permafrost carbon−climate feedback is sensitive to deep soil carbon decomposability but not deep soil nitrogen dynamics

PubMed Central

Koven, Charles D.; Lawrence, David M.; Riley, William J.

2015-01-01

Permafrost soils contain enormous amounts of organic carbon whose stability is contingent on remaining frozen. With future warming, these soils may release carbon to the atmosphere and act as a positive feedback to climate change. Significant uncertainty remains on the postthaw carbon dynamics of permafrost-affected ecosystems, in particular since most of the carbon resides at depth where decomposition dynamics may differ from surface soils, and since nitrogen mineralized by decomposition may enhance plant growth. Here we show, using a carbon−nitrogen model that includes permafrost processes forced in an unmitigated warming scenario, that the future carbon balance of the permafrost region is highly sensitive to the decomposability of deeper carbon, with the net balance ranging from 21 Pg C to 164 Pg C losses by 2300. Increased soil nitrogen mineralization reduces nutrient limitations, but the impact of deep nitrogen on the carbon budget is small due to enhanced nitrogen availability from warming surface soils and seasonal asynchrony between deeper nitrogen availability and plant nitrogen demands. Although nitrogen dynamics are highly uncertain, the future carbon balance of this region is projected to hinge more on the rate and extent of permafrost thaw and soil decomposition than on enhanced nitrogen availability for vegetation growth resulting from permafrost thaw. PMID:25775603

Effects of fire alone or combined with thinning on tissue nutrient concentrations and nutrient resorption in Desmodium nudiflorum.

PubMed

Huang, Jianjun; Boerner, Ralph E J

2007-08-01

This study examined tissue nutrient responses of Desmodium nudiflorum to changes in soil total inorganic nitrogen (TIN) and available phosphorus (P) that occurred as the result of the application of alternative forest management strategies, namely (1) prescribed low-intensity fire (B), (2) overstory thinning followed by prescribed fire (T + B), and (3) untreated control C), in two Quercus-dominated forests in the State of Ohio, USA. In the fourth growing season after a first fire, TIN was significantly greater in the control plots (9.8 mg/kg) than in the B (5.5 mg/kg) and T + B (6.4 mg/kg) plots. Similarly, available P was greater in the control sites (101 microg/g) than in the B (45 microg/kg) and T + B (65 microg/kg) sites. Leaf phosphorus ([P]) was higher in the plants from control site (1.86 mg/g) than in either the B (1.77 mg/g) or T + B plants (1.73 mg/g). Leaf nitrogen ([N]) and root [N] showed significant site-treatment interactive effects, while stem [N], stem [P], and root [P] did not differ significantly among treatments. During the first growing season after a second fire, leaf [N], stem [N], litter [P] and available soil [P] were consistently lower in plots of the manipulated treatments than in the unmanaged control plot, whereas the B and T + B plots did not differ significantly from each other. N resorption efficiency was positively correlated with the initial foliar [N] in the manipulated (B and T + B) sites, but there was no such relation in the unmanaged control plots. P resorption efficiency was positively correlated with the initial leaf [P] in both the control and manipulated plots. Leaf nutrient status was strongly influenced by soil nutrient availability shortly after fire, but became more influenced by topographic position in the fourth year after fire. Nutrient resorption efficiency was independent of soil nutrient availability. These findings enrich our understanding of the effects of ecosystem restoration treatments on soil nutrient availability, plant nutrient relations, and plant-soil interactions at different temporal scales.

A Comparison of the Role of Episode Nutrient Supply on Pathways of Carbon in Upwelling Regimes

NASA Technical Reports Server (NTRS)

Carr, M. E.

1997-01-01

Nutrient supply is episode in the ocean even in regions of fairly high and continuous nutrient supply, such as coastal upwelling regimes. The structure of the ecosystem depends on nutrient availability and the different requirements of phytoplankton cells.

Bayesian Modeling of the Assimilative Capacity Component of Stream Nutrient Export

EPA Science Inventory

Implementing stream restoration techniques and best management practices to reduce nonpoint source nutrients implies enhancement of the assimilative capacity for the stream system. In this paper, a Bayesian method for evaluating this component of a TMDL load capacity is developed...

Greenhouse gas emissions in an agroforestry system in the southeastern USA

USDA-ARS?s Scientific Manuscript database

Agroforestry systems may provide diverse ecosystem services and economic benefits that conventional agriculture cannot, e.g. potentially mitigating greenhouse gas emissions by enhancing nutrient cycling, since tree roots can capture nutrients not taken up by crops. However, greenhouse gas emission ...

The influence of particles recycling on the geochemistry of sediments in a large tropical dam lake in the Amazonian region, Brazil

NASA Astrophysics Data System (ADS)

Fonseca, Rita; Pinho, Catarina; Oliveira, Manuela

2016-12-01

As a result of over-erosion of soils, the fine particles, which contain the majority of nutrients, are easily washed away from soils, which become deficient in a host of components, accumulating in lakes. On one hand, the accumulation of nutrients-rich sediments are a problem, as they affect the quality of the overlying water and decrease the water storage capacity of the system; on the other hand, sediments may constitute an important resource, as they are often extremely rich in organic and inorganic nutrients in readily available forms. In the framework of an extensive work on the use of rock related materials to enhance the fertility of impoverish soils, this study aimed to evaluate the role on the nutrients cycle, of particles recycling processes from the watershed to the bottom of a large dam reservoir, at a wet tropical region under high weathering conditions. The study focus on the mineralogical transformations that clay particles undergo from the soils of the drainage basin to their final deposition within the reservoir and their influence in terms of the geochemical characteristics of sediments. We studied the bottom sediments that accumulate in two distinct seasonal periods in Tucuruí reservoir, located in the Amazonian Basin, Brazil, and soils from its drainage basin. The surface layers of sediments in twenty sampling points with variable depths, are representative of the different morphological sections of the reservoir. Nineteen soil samples, representing the main soil classes, were collected near the margins of the reservoir. Sediments and soils were subjected to the same array of physical, mineralogical and geochemical analyses: (1) texture, (2) characterization and semi-quantification of the clay fraction mineralogy and (3) geochemical analysis of the total concentration of major elements, organic compounds (organic C and nitrogen), soluble fractions of nutrients (P and K), exchangeable fractions (cation exchange capacity, exchangeable bases and acidity) and pH(H2O). There is a remarkable homogeneity in the sedimentary distribution along the reservoir in terms of the texture and mineralogy of the clay fraction and of the chemistry of the total, soluble and exchangeable phases. These observations contrast with the physical, morphological and chemical heterogeneity of the soils and the setting lithology. Most of the sediments has a higher contribution of fine-grained material and the mineralogy of the clay fraction is dominated by kaolinite in soils and kaolinite and illite in sediments, followed by lesser amounts of gibbsite, goethite, and metahaloisite and by small/vestigial contents of chlorite and smectite. The sediments are mainly inherited from the watershed but there exist marked differences between the accumulated sediments and their parent materials. These differences mainly come from the selective erosion of fine-grained particles and the extreme climatic conditions which enhance complex transformations of mineralogical and chemical nature. Compared with the parental soils, the reservoir sediments show the following differences: (1) enrichment in fine-grained and less dense inorganic particles, (2) aggradative mineralogical transformations, including enrichment in clay minerals with higher cationic adsorption and exchange capacity, (3) degradation of the crystalline structure of Fe- and Al-oxides (goethite, gibbsite), (4) increase in easily leached elements (Mg, Ca, P, K, Na) and decrease in chemically less mobile elements (Si, Fe) and (5) higher contents of organic carbon, nitrogen, and soluble forms of P and K, mainly concentrated in the clay fraction. These transformations are extremely important in the nutrients cycle, denoting that sediments represent an efficient sink for nutrients from the over-erosion of soils. Mineral and organic compounds can permanently or temporarily sequester these nutrients, recycling them and enhancing their availability through the slow release of components from relatively loose crystal structures. These processes can easily explain the enrichment in soluble and exchangeable forms of elements such as P, K, Ca or Mg. This study conclude that the particles recycling in a large tropical dam reservoir which receives high fluxes of allochthonous nutrients, has an important role in the good quality of sediments for agricultural use and in the profitable use of this technology to recover depleted soils in remediation projects in regions near large hydroelectric plants.

Enhancement and inhibition of microbial activity in hydrocarbon- contaminated arctic soils: Implications for nutrient-amended bioremediation

USGS Publications Warehouse

Braddock, J.F.; Ruth, M.L.; Catterall, P.H.; Walworth, J.L.; McCarthy, K.A.

1997-01-01

Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) end low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus. When nutrients were added to soil in the field at three levels of N:P (100:45, 200:90, and 300:135 mg/kg soil), the greatest stimulation in microbial activity occurred at the lowest, rather than the highest, level of nutrient addition. The total soil-water potentials ranged from -2 to -15 bar with increasing levels of fertilizer. Semivolatile hydrocarbon concentrations declined significantly only in the soils treated at the low fertilizer level. These results indicate that an understanding of nutrient effects at a specific site is essential for successful bioremediation.Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) and low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus. When nutrients were added to soil in the field at three levels of N:P (100:45, 200:90, and 300:135 mg/kg soil), the greatest stimulation in microbial activity occurred at the lowest, rather than the highest, level of nutrient addition. The total soil-water potentials ranged from -2 to -15 bar with increasing levels of fertilizer. Semi-volatile hydrocarbon concentrations declined significantly only in the soils treated at the low fertilizer level. These results indicate that an understanding of nutrient effects at a specific site is essential for successful bioremediation.

[An optical-fiber-sensor-based spectrophotometer for soil non-metallic nutrient determination].

PubMed

He, Dong-xian; Hu, Juan-xiu; Lu, Shao-kun; He, Hou-yong

2012-01-01

In order to achieve rapid, convenient and efficient soil nutrient determination in soil testing and fertilizer recommendation, a portable optical-fiber-sensor-based spectrophotometer including immersed fiber sensor, flat field holographic concave grating, and diode array detector was developed for soil non-metallic nutrient determination. According to national standard of ultraviolet and visible spectrophotometer with JJG 178-2007, the wavelength accuracy and repeatability, baseline stability, transmittance accuracy and repeatability measured by the prototype instrument were satisfied with the national standard of III level; minimum spectral bandwidth, noise and excursion, and stray light were satisfied with the national standard of IV level. Significant linear relationships with slope of closing to 1 were found between the soil available nutrient contents including soil nitrate nitrogen, ammonia nitrogen, available phosphorus, available sulfur, available boron, and organic matter measured by the prototype instrument compared with that measured by two commercial single-beam-based and dual-beam-based spectrophotometers. No significant differences were revealed from the above comparison data. Therefore, the optical-fiber-sensor-based spectrophotometer can be used for rapid soil non-metallic nutrient determination with a high accuracy.

Soil Chemical Property Changes in Eggplant/Garlic Relay Intercropping Systems under Continuous Cropping

PubMed Central

Wang, Mengyi; Wu, Cuinan; Cheng, Zhihui; Meng, Huanwen; Zhang, Mengru; Zhang, Hongjing

2014-01-01

Soil sickness is a critical problem for eggplant (Solanum melongena L.) under continuous cropping that affects sustainable eggplant production. Relay intercropping is a significant technique on promoting soil quality, improving eco-environment, and raising output. Field experiments were conducted from September 2010 to November 2012 in northwest China to determine the effects of relay intercropping eggplant with garlic (Allium sativum L.) on soil enzyme activities, available nutrient contents, and pH value under a plastic tunnel. Three treatments were in triplicate using randomized block design: eggplant monoculture (CK), eggplant relay intercropping with normal garlic (NG) and eggplant relay intercropping with green garlic (GG). The major results are as follows: (1) the activities of soil invertase, urease, and alkaline phosphatase were generally enhanced in NG and GG treatments; (2) relay intercropping significantly increased the soil available nutrient contents, and they were mostly higher in GG than NG. On April 11, 2011, the eggplant/garlic co-growth stage, the available nitrogen content in GG was 76.30 mg·kg−1, significantly higher than 61.95 mg·kg−1 in NG. For available potassium on April 17, 2012, they were 398.48 and 387.97 mg·kg−1 in NG and GG, both were significantly higher than 314.84 mg·kg−1 in CK; (3) the soil pH showed a significantly higher level in NG treatment, but lower in GG treatment compared with CK. For the last samples in 2012, soil pH in NG and GG were 7.70 and 7.46, the highest and lowest one among them; (4) the alkaline phosphatase activity and pH displayed a similar decreasing trend with continuous cropping. These findings indicate that relay intercropping eggplant with garlic could be an ideal farming system to effectively improve soil nutrient content, increase soil fertility, and alleviate soil sickness to some extent. These findings are important in helping to develop sustainable eggplant production. PMID:25340875

Evidence for micronutrient limitation of biological soil crusts: Importance to arid-lands restoration

USGS Publications Warehouse

Bowker, M.A.; Belnap, J.; Davidson, D.W.; Phillips, S.L.

2005-01-01

Desertification is a global problem, costly to national economies and human societies. Restoration of biological soil crusts (BSCs) may have an important role to play in the reversal of desertification due to their ability to decrease erosion and enhance soil fertility. To determine if there is evidence that lower fertility may hinder BSC recolonization, we investigated the hypothesis that BSC abundance is driven by soil nutrient concentrations. At a regional scale (north and central Colorado Plateau, USA), moss and lichen cover and richness are correlated with a complex water-nutrient availability gradient and have approximately six-fold higher cover and approximately two-fold higher species richness on sandy soils than on shale-derived soils. At a microscale, mosses and lichens are overrepresented in microhabitats under the north sides of shrub canopies, where water and nutrients are more available. At two spatial scales, and at the individual species and community levels, our data are consistent with the hypothesis that distributions of BSC organisms are determined largely by soil fertility. The micronutrients Mn and Zn figured prominently and consistently in the various analyses, strongly suggesting that these elements are previously unstudied limiting factors in BSC development. Structural-equation modeling of our data is most consistent with the hypothesis of causal relationships between the availability of micronutrients and the abundance of the two major nitrogen (N) fixers of BSCs. Specifically, higher Mn availability may determine greater Collema tenax abundance, and both Mn and Zn may limit Collema coccophorum; alternative causal hypotheses were less consistent with the data. We propose experimental trials of micronutrient addition to promote the restoration of BSC function on disturbed lands. Arid lands, where BSCs are most prevalent, cover ???40% of the terrestrial surface of the earth; thus the information gathered in this study is potentially useful in many places worldwide. ?? 2005 by the Ecological Society of America.

Soil chemical property changes in eggplant/garlic relay intercropping systems under continuous cropping.

PubMed

Wang, Mengyi; Wu, Cuinan; Cheng, Zhihui; Meng, Huanwen; Zhang, Mengru; Zhang, Hongjing

2014-01-01

Soil sickness is a critical problem for eggplant (Solanum melongena L.) under continuous cropping that affects sustainable eggplant production. Relay intercropping is a significant technique on promoting soil quality, improving eco-environment, and raising output. Field experiments were conducted from September 2010 to November 2012 in northwest China to determine the effects of relay intercropping eggplant with garlic (Allium sativum L.) on soil enzyme activities, available nutrient contents, and pH value under a plastic tunnel. Three treatments were in triplicate using randomized block design: eggplant monoculture (CK), eggplant relay intercropping with normal garlic (NG) and eggplant relay intercropping with green garlic (GG). The major results are as follows: (1) the activities of soil invertase, urease, and alkaline phosphatase were generally enhanced in NG and GG treatments; (2) relay intercropping significantly increased the soil available nutrient contents, and they were mostly higher in GG than NG. On April 11, 2011, the eggplant/garlic co-growth stage, the available nitrogen content in GG was 76.30 mg·kg(-1), significantly higher than 61.95 mg·kg(-1) in NG. For available potassium on April 17, 2012, they were 398.48 and 387.97 mg·kg(-1) in NG and GG, both were significantly higher than 314.84 mg·kg(-1) in CK; (3) the soil pH showed a significantly higher level in NG treatment, but lower in GG treatment compared with CK. For the last samples in 2012, soil pH in NG and GG were 7.70 and 7.46, the highest and lowest one among them; (4) the alkaline phosphatase activity and pH displayed a similar decreasing trend with continuous cropping. These findings indicate that relay intercropping eggplant with garlic could be an ideal farming system to effectively improve soil nutrient content, increase soil fertility, and alleviate soil sickness to some extent. These findings are important in helping to develop sustainable eggplant production.

LABORATORY EVALUATION OF OIL SPILL BIOREMEDIATION PRODUCTS IN SALT AND FRESHWATER SYSTEMS

EPA Science Inventory

Ten oil spill bioremediation products were tested in the laboratory for their ability to enhance biodegradation of weathered Alaskan North Slope crude oil in both fresh and salt-water media. The products included: nutrients to stimulate inoculated microorganisms, nutrients plus a...

Carrot, Corn, Lettuce and Soybean Nutrient Contents are Affected by Biochar

EPA Science Inventory

Biochar, the carbon-rich material remaining after pyrolysis of cellulosic and manure feedstocks, has the potential as a soil amendment to sequester carbon and to improve soil water-holding and nutrient properties- thereby enhancing plant growth. However, biochar produced from so...

The Intrauterine Growth Restriction Phenotype: Fetal Adaptations and Potential Implications for Later Life Insulin Resistance and Diabetes

PubMed Central

Thorn, Stephanie R.; Rozance, Paul J.; Brown, Laura D.; Hay, William W.

2011-01-01

The intrauterine growth restricted (IUGR) fetus develops unique metabolic adaptations in response to exposure to reduced nutrient supply. These adaptations provide survival value for the fetus by enhancing the capacity of the fetus to take up and use nutrients, thereby reducing the need for nutrient supply. Each organ and tissue in the fetus adapts differently, with the brain showing the greatest capacity for maintaining nutrient supply and growth. Such adaptations, if persistent, also have the potential in later life to promote nutrient uptake and storage, which directly lead to complications of obesity, insulin resistance, reduced insulin production, and type 2 diabetes. PMID:21710398

Root Cortical Aerenchyma Enhances the Growth of Maize on Soils with Suboptimal Availability of Nitrogen, Phosphorus, and Potassium1[W][OA

PubMed Central

Postma, Johannes Auke; Lynch, Jonathan Paul

2011-01-01

Root cortical aerenchyma (RCA) is induced by hypoxia, drought, and several nutrient deficiencies. Previous research showed that RCA formation reduces the respiration and nutrient content of root tissue. We used SimRoot, a functional-structural model, to provide quantitative support for the hypothesis that RCA formation is a useful adaptation to suboptimal availability of phosphorus, nitrogen, and potassium by reducing the metabolic costs of soil exploration in maize (Zea mays). RCA increased the growth of simulated 40-d-old maize plants up to 55%, 54%, or 72% on low nitrogen, phosphorus, or potassium soil, respectively, and reduced critical fertility levels by 13%, 12%, or 7%, respectively. The greater utility of RCA on low-potassium soils is associated with the fact that root growth in potassium-deficient plants was more carbon limited than in phosphorus- and nitrogen-deficient plants. In contrast to potassium-deficient plants, phosphorus- and nitrogen-deficient plants allocate more carbon to the root system as the deficiency develops. The utility of RCA also depended on other root phenes and environmental factors. On low-phosphorus soils (7.5 μm), the utility of RCA was 2.9 times greater in plants with increased lateral branching density than in plants with normal branching. On low-nitrate soils, the utility of RCA formation was 56% greater in coarser soils with high nitrate leaching. Large genetic variation in RCA formation and the utility of RCA for a range of stresses position RCA as an interesting crop-breeding target for enhanced soil resource acquisition. PMID:21628631

Sequential nutrient uptake as a potential mechanism for phytoplankton to maintain high primary productivity and balanced nutrient stoichiometry

NASA Astrophysics Data System (ADS)

Yin, Kedong; Liu, Hao; Harrison, Paul J.

2017-05-01

We hypothesize that phytoplankton have the sequential nutrient uptake strategy to maintain nutrient stoichiometry and high primary productivity in the water column. According to this hypothesis, phytoplankton take up the most limiting nutrient first until depletion, continue to draw down non-limiting nutrients and then take up the most limiting nutrient rapidly when it is available. These processes would result in the variation of ambient nutrient ratios in the water column around the Redfield ratio. We used high-resolution continuous vertical profiles of nutrients, nutrient ratios and on-board ship incubation experiments to test this hypothesis in the Strait of Georgia. At the surface in summer, ambient NO3- was depleted with excess PO43- and SiO4- remaining, and as a result, both N : P and N : Si ratios were low. The two ratios increased to about 10 : 1 and 0. 45 : 1, respectively, at 20 m. Time series of vertical profiles showed that the leftover PO43- continued to be removed, resulting in additional phosphorus storage by phytoplankton. The N : P ratios at the nutricline in vertical profiles responded differently to mixing events. Field incubation of seawater samples also demonstrated the sequential uptake of NO3- (the most limiting nutrient) and then PO43- and SiO4- (the non-limiting nutrients). This sequential uptake strategy allows phytoplankton to acquire additional cellular phosphorus and silicon when they are available and wait for nitrogen to become available through frequent mixing of NO3- (or pulsed regenerated NH4). Thus, phytoplankton are able to maintain high productivity and balance nutrient stoichiometry by taking advantage of vigorous mixing regimes with the capacity of the stoichiometric plasticity. To our knowledge, this is the first study to show the in situ dynamics of continuous vertical profiles of N : P and N : Si ratios, which can provide insight into the in situ dynamics of nutrient stoichiometry in the water column and the inference of the transient status of phytoplankton nutrient stoichiometry in the coastal ocean.

Diversifying crop rotations with pulses enhances system productivity

PubMed Central

Gan, Yantai; Hamel, Chantal; O’Donovan, John T.; Cutforth, Herb; Zentner, Robert P.; Campbell, Con A.; Niu, Yining; Poppy, Lee

2015-01-01

Agriculture in rainfed dry areas is often challenged by inadequate water and nutrient supplies. Summerfallowing has been used to conserve rainwater and promote the release of nitrogen via the N mineralization of soil organic matter. However, summerfallowing leaves land without any crops planted for one entire growing season, creating lost production opportunity. Additionally, summerfallowing has serious environmental consequences. It is unknown whether alternative systems can be developed to retain the beneficial features of summerfallowing with little or no environmental impact. Here, we show that diversifying cropping systems with pulse crops can enhance soil water conservation, improve soil N availability, and increase system productivity. A 3-yr cropping sequence study, repeated for five cycles in Saskatchewan from 2005 to 2011, shows that both pulse- and summerfallow-based systems enhances soil N availability, but the pulse system employs biological fixation of atmospheric N2, whereas the summerfallow-system relies on ‘mining’ soil N with depleting soil organic matter. In a 3-yr cropping cycle, the pulse system increased total grain production by 35.5%, improved protein yield by 50.9%, and enhanced fertilizer-N use efficiency by 33.0% over the summerfallow system. Diversifying cropping systems with pulses can serve as an effective alternative to summerfallowing in rainfed dry areas. PMID:26424172

Nutrient Composition of Enhanced and Non-enhanced Boneless Skinless Chicken Breast Fillets Purchased from Retail

USDA-ARS?s Scientific Manuscript database

The objective of this study was to compare nutritional composition of raw enhanced (E) and non-enhanced (NE), boneless, skinless chicken breast fillets (pectoralis major), obtained from U.S. retail supermarkets. Fillets were either enhanced with a salt, phosphate, and water solution, or were non-en...

Dactylorhiza maculata, Platanthera bifolia and Listera ovata survive N application under P limitation

NASA Astrophysics Data System (ADS)

Hejcman, Michal; Schellberg, Jürgen; Pavlů, Vilém

2010-11-01

Increased nutrient availability is generally believed to be harmful for terrestrial orchids. However, no information is available on whether grassland orchids survive decades-long calcium (Ca), nitrogen (N), phosphorus (P) and potassium (K) application. We took advantage of sampling in one of the oldest long-term experiments in the world, the Rengen Grassland Experiment (RGE), which was established in Germany in 1941 on low-productive Violion caninae grassland, and we monitored orchids from 2005 to 2009. Dactylorhiza maculata, Platanthera bifolia and Listera ovata survived decades-long application of Ca and CaN fertilizer, but not CaN together with P. Cover of D. maculata was highest in areas of Ca treatment. The number of flowers per plant of L. ovata was significantly higher in the CaN treatment compared with the control indicating that enhanced N availability stimulated its growth. Long-term N application (NH 4NO 3 at an annual rate of 100 kg N ha -1) was not fatal to the studied orchids if not accompanied by P application. It is more likely that enhanced N availability can cause loss of studied orchids only where the availability of P in soil is high enough to enable the growth of productive species that can better compete for light on eutrophic soils.

Enhanced terrestrial carbon uptake: global drivers and implications for the growth rate of atmospheric CO2.

NASA Astrophysics Data System (ADS)

Keenan, Trevor F.; Prentice, Colin; Canadell, Josep; Williams, Christopher; Han, Wang; Riley, William; Zhu, Qing; Koven, Charlie; Chambers, Jeff

2017-04-01

In this presentation we will focus on using decadal changes in the global carbon cycle to better understand how ecosystems respond to changes in CO2 concentration, temperature, and water and nutrient availability. Using global carbon budget estimates, ground, atmospheric and satellite observations, and multiple process-based global vegetation models, we examine the causes and consequences of the long-term changes in the terrestrial carbon sink. We show that over the past century the sink has been greatly enhanced, largely due to the effect of elevated CO2 on photosynthesis dominating over warming induced increases in respiration. We also examine the relative roles of greening, water and nutrients, along with individual events such as El Nino. We show that a slowdown in the rate of warming over land since the start of the 21st century likely led to a large increase in the sink, and that this increase was sufficient to lead to a pause in the growth rate of atmospheric CO2. We also show that the recent El Nino resulted in the highest growth rate of atmospheric CO2 ever recorded. Our results provide evidence of the relative roles of CO2 fertilization and warming induced respiration in the global carbon cycle, along with an examination of the impact of climate extremes.

Soil and pasture P concentration in a Fraxinus excelsior L. silvopastoral system fertilised with different types of sewage sludge

NASA Astrophysics Data System (ADS)

Ferreiro-Domínguez, Nuria; Nair, Vimala; Rigueiro-Rodríguez, Antonio; Rosa Mosquera-Losada, María

2015-04-01

In Europe, sewage sludge should be stabilised before using as fertiliser in agriculture. Depending on the stabilisation process that is used, sewage sludge has different characteristics, nutrient contents and soil nutrient incorporation rates. Sewage sludge is usually applied on a plant-available N or total metal concentration basic, and therefore, P concentrations can be well above crop needs. Leaching of excess P can threaten surface and ground waters with eutrophication. In this context, recent studies have demonstrated that the implementation of agroforestry systems could reduce the P leaching risk compared with conventional agricultural systems due to the different localisation of tree and crop roots which enhance nutrient uptake. The aim of this study was to evaluate during three consecutive years the effect of municipal sewage sludge stabilised by anaerobic digestion, composting, and pelletisation on concentration of P in soil and pasture compared to control treatments (mineral and no fertilisation) in a silvopastoral system established under Fraxinus excelsior L. in Galicia (Spain). The results showed that at the beginning of the study, the fertilisation with mineral increased more the total and available P in soil than the fertilisation with sewage sludge probably because the sludge nutrient release rate is slower than those from mineral fertilisers. The increment of soil available P caused by the mineral fertiliser implied an improvement of the P concentration in the pasture. However, in the last year of the experiment it was observed a positive effect of the fertilisation with pelletised sludge on the concentration of P in pasture compared with the composted sludge and the mineral fertiliser probably due to the annual application of this type of sludge. Therefore, the establishment of silvopastoral systems and their fertilisation with pelletized sludge should be recommended because the pelletized sludge increases the concentration of P in the pasture and reduces the application and storage costs due to its lower proportion of water than the other types of sludge tested. At the same time, the integration of trees in agricultural areas decreases the problem of environmental impact resulting from addition of organic and inorganic fertilisers on soils.

Corn grain yield and nutrient uptake from application of enhanced-efficiency nitrogen fertilizers

USDA-ARS?s Scientific Manuscript database

Increasing demand for food and agricultural products directly impact the use of chemical fertilizers particularly nitrogen (N). This study examined corn grain yield and nutrient uptake resulting from applications of different N fertilizer sources, urea (U), urea-ammonium nitrate (UAN), ammonium nitr...

USDA Branded Food Products Database, Release 2

USDA-ARS?s Scientific Manuscript database

The USDA Branded Food Products Database is the ongoing result of a Public-Private Partnership (PPP), whose goal is to enhance public health and the sharing of open data by complementing the USDA National Nutrient Database for Standard Reference (SR) with nutrient composition of branded foods and pri...

When microbes and consumers determine the limiting nutrient of autotrophs: a theoretical analysis

PubMed Central

Cherif, Mehdi; Loreau, Michel

2008-01-01

Ecological stoichiometry postulates that differential nutrient recycling of elements such as nitrogen and phosphorus by consumers can shift the element that limits plant growth. However, this hypothesis has so far considered the effect of consumers, mostly herbivores, out of their food-web context. Microbial decomposers are important components of food webs, and might prove as important as consumers in changing the availability of elements for plants. In this theoretical study, we investigate how decomposers determine the nutrient that limits plants, both by feeding on nutrients and organic carbon released by plants and consumers, and by being fed upon by omnivorous consumers. We show that decomposers can greatly alter the relative availability of nutrients for plants. The type of limiting nutrient promoted by decomposers depends on their own elemental composition and, when applicable, on their ingestion by consumers. Our results highlight the limitations of previous stoichiometric theories of plant nutrient limitation control, which often ignored trophic levels other than plants and herbivores. They also suggest that detrital chains play an important role in determining plant nutrient limitation in many ecosystems. PMID:18854301

Nitrogenase and Alkaline Phosphatase Activity in Wetland Metaphyton: Implications for Primary Production and CNP Composition

NASA Astrophysics Data System (ADS)

Scott, T.; Doyle, R.

2005-05-01

Longitudinal gradients of nutrient availability often occur along the flow path of water in freshwater wetlands. Differential removal efficiencies of water column nitrogen (N) and phosphorus (P) may increase the severity of nutrient deficiency and possibly change the nutrient that limits primary production. A previous study demonstrated that periphyton in the Lake Waco Wetlands (LWW), near Waco, Texas, USA, are generally more P limited near the inflow and become increasingly N limited as distance from the inflow increases. Therefore, spatial heterogeneity in nutrient availability likely influences both the structure and function of periphyton assemblages within this system. In this ongoing study, we are evaluating the relationships between metaphyton primary production, nitrogenase activity, alkaline phosphatase activity, and CNP stoichiometry in areas of differing nutrient limitation within the LWW. As expected, primary production is generally greatest in areas where nitrogenase and alkaline phosphatase activities are minimal. However, expected increases in C:N ratios in areas of greatest nutrient deficiency have not been frequently observed. Decreased primary production and increased enzyme mediated nutrient uptake appear to balance metaphyton nutrient content in these areas.

Model-based analysis of environmental controls over ecosystem primary production in an alpine tundra dry meadow

DOE PAGES

Fan, Zhaosheng; Neff, Jason C.; Wieder, William R.

2016-02-10

We investigated several key limiting factors that control alpine tundra productivity by developing an ecosystem biogeochemistry model. The model simulates the coupled cycling of carbon (C), nitrogen (N), and phosphorus (P) and their interactions with gross primary production (GPP). It was parameterized with field observations from an alpine dry meadow ecosystem using a global optimization strategy to estimate the unknown parameters. The model, along with the estimated parameters, was first validated against independent data and then used to examine the environmental controls over plant productivity. Our results show that air temperature is the strongest limiting factor to GPP in themore » early growing season, N availability becomes important during the middle portion of the growing season, and soil moisture is the strongest limiting factors by late in the growing season. Overall, the controls over GPP during the growing season, from strongest to weakest, are soil moisture content, air temperature, N availability, and P availability. This simulation provides testable predictions of the shifting nature of physical and nutrient limitations on plant growth. The model also indicates that changing environmental conditions in the alpine will likely lead to changes in productivity. For example, warming eliminates the control of P availability on GPP and makes N availability surpass air temperature to become the second strongest limiting factor. In contrast, an increase in atmospheric nutrient deposition eliminates the control of N availability and enhances the importance of P availability. Furthermore, these analyses provide a quantitative and conceptual framework that can be used to test predictions and refine ecological analyses at this long-term ecological research site.« less

Model-based analysis of environmental controls over ecosystem primary production in an alpine tundra dry meadow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Zhaosheng; Neff, Jason C.; Wieder, William R.

We investigated several key limiting factors that control alpine tundra productivity by developing an ecosystem biogeochemistry model. The model simulates the coupled cycling of carbon (C), nitrogen (N), and phosphorus (P) and their interactions with gross primary production (GPP). It was parameterized with field observations from an alpine dry meadow ecosystem using a global optimization strategy to estimate the unknown parameters. The model, along with the estimated parameters, was first validated against independent data and then used to examine the environmental controls over plant productivity. Our results show that air temperature is the strongest limiting factor to GPP in themore » early growing season, N availability becomes important during the middle portion of the growing season, and soil moisture is the strongest limiting factors by late in the growing season. Overall, the controls over GPP during the growing season, from strongest to weakest, are soil moisture content, air temperature, N availability, and P availability. This simulation provides testable predictions of the shifting nature of physical and nutrient limitations on plant growth. The model also indicates that changing environmental conditions in the alpine will likely lead to changes in productivity. For example, warming eliminates the control of P availability on GPP and makes N availability surpass air temperature to become the second strongest limiting factor. In contrast, an increase in atmospheric nutrient deposition eliminates the control of N availability and enhances the importance of P availability. Furthermore, these analyses provide a quantitative and conceptual framework that can be used to test predictions and refine ecological analyses at this long-term ecological research site.« less

Relationship between soil nutrients and mycorrhizal associations of two Bipinnula species (Orchidaceae) from central Chile.

PubMed

Mujica, María Isabel; Saez, Nicolás; Cisternas, Mauricio; Manzano, Marlene; Armesto, Juan J; Pérez, Fernanda

2016-07-01

Mycorrhizal associations are influenced by abiotic and biotic factors, including climate, soil conditions and the identity of host plants. However, the effect of environmental conditions on orchid mycorrhizal associations remains poorly understood. The present study examined how differences in soil nutrient availability are related to the diversity and composition of mycorrhizal fungi associated with two terrestrial orchid species from central Chile. For 12 populations of Bipinnula fimbriata and B. plumosa, OTU (operational taxonomic unit) richness, phylogenetic diversity and community composition of mycorrhizal fungi in root samples were estimated using internal transcribed spacer (ITS) sequences. Then, these mycorrhizal diversity variables were related to soil nutrients and host species using generalized linear models and non-metric multidimensional scaling. Variation in OTU composition of mycorrhizal fungi among sites was explained mainly by orchid host species. Fungi in Tulasnellaceae and Ceratobasidiaceae were isolated from both orchid species, but the former were more frequent in B. fimbriata and the latter in B. plumosa. Soil nutrients and orchid host species had significant effects on OTU richness and phylogenetic diversity. Mycorrhizal diversity decreased in habitats with higher N in both species and increased with P availability only in B. fimbriata The results suggest that soil nutrient availability modulates orchid mycorrhizal associations and provide support for the hypothesis that specialization is favoured by higher soil nutrient availability. Inter-specific differences in mycorrhizal composition can arise due to a geographical pattern of distribution of orchid mycorrhizal fungi, host preferences for fungal partners or differential performance of mycorrhizal fungi under different nutrient availabilities. Further experiments are needed to evaluate these hypotheses. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Relationship between soil nutrients and mycorrhizal associations of two Bipinnula species (Orchidaceae) from central Chile

PubMed Central

Mujica, María Isabel; Saez, Nicolás; Cisternas, Mauricio; Manzano, Marlene; Armesto, Juan J.; Pérez, Fernanda

2016-01-01

Background and Aims Mycorrhizal associations are influenced by abiotic and biotic factors, including climate, soil conditions and the identity of host plants. However, the effect of environmental conditions on orchid mycorrhizal associations remains poorly understood. The present study examined how differences in soil nutrient availability are related to the diversity and composition of mycorrhizal fungi associated with two terrestrial orchid species from central Chile. Methods For 12 populations of Bipinnula fimbriata and B. plumosa, OTU (operational taxonomic unit) richness, phylogenetic diversity and community composition of mycorrhizal fungi in root samples were estimated using internal transcribed spacer (ITS) sequences. Then, these mycorrhizal diversity variables were related to soil nutrients and host species using generalized linear models and non-metric multidimensional scaling. Key Results Variation in OTU composition of mycorrhizal fungi among sites was explained mainly by orchid host species. Fungi in Tulasnellaceae and Ceratobasidiaceae were isolated from both orchid species, but the former were more frequent in B. fimbriata and the latter in B. plumosa. Soil nutrients and orchid host species had significant effects on OTU richness and phylogenetic diversity. Mycorrhizal diversity decreased in habitats with higher N in both species and increased with P availability only in B. fimbriata. Conclusions The results suggest that soil nutrient availability modulates orchid mycorrhizal associations and provide support for the hypothesis that specialization is favoured by higher soil nutrient availability. Inter-specific differences in mycorrhizal composition can arise due to a geographical pattern of distribution of orchid mycorrhizal fungi, host preferences for fungal partners or differential performance of mycorrhizal fungi under different nutrient availabilities. Further experiments are needed to evaluate these hypotheses. PMID:27311572

Dynamic shear-stress-enhanced rates of nutrient consumption in gas-liquid semi-continuous-flow suspensions

NASA Astrophysics Data System (ADS)

Belfiore, Laurence A.; Volpato, Fabio Z.; Paulino, Alexandre T.; Belfiore, Carol J.

2011-12-01

The primary objective of this investigation is to establish guidelines for generating significant mammalian cell density in suspension bioreactors when stress-sensitive kinetics enhance the rate of nutrient consumption. Ultra-low-frequency dynamic modulations of the impeller (i.e., 35104 Hz) introduce time-dependent oscillatory shear into this transient analysis of cell proliferation under semi-continuous creeping flow conditions. Greater nutrient consumption is predicted when the amplitude A of modulated impeller rotation increases, and stress-kinetic contributions to nutrient consumption rates increase linearly at higher modulation frequency via an application of fluctuation-dissipation response. Interphase mass transfer is required to replace dissolved oxygen as it is consumed by aerobic nutrient consumption in the liquid phase. The theory and predictions described herein could be important at small length scales in the creeping flow regime where viscous shear is significant at the interface between the nutrient medium and isolated cells in suspension. Two-dimensional flow around spherically shaped mammalian cells, suspended in a Newtonian culture medium, is analyzed to calculate the surface-averaged magnitude of the velocity gradient tensor and modify homogeneous rates of nutrient consumption that are stimulated by viscous shear, via the formalism of stress-kinetic reciprocal relations that obey Curie's theorem in non-equilibrium thermodynamics. Time constants for stress-free free and stress-sensitive stress nutrient consumption are defined and quantified to identify the threshold (i.e., stress,threshold) below which the effect of stress cannot be neglected in accurate predictions of bioreactor performance. Parametric studies reveal that the threshold time constant for stress-sensitive nutrient consumption stress,threshold decreases when the time constant for stress-free nutrient consumption free is shorter. Hence, stress,threshold depends directly on free. In other words, the threshold rate of stress-sensitive nutrient consumption is higher when the stress-free rate of nutrient consumption increases. Modulated rotation of the impeller, superimposed on steady shear, increases stress,threshold when free is constant, and stress,threshold depends directly on the amplitude A of these angular velocity modulations.

Nutritional strategies to optimize dairy cattle immunity.

PubMed

Sordillo, L M

2016-06-01

Dairy cattle are susceptible to increased incidence and severity of both metabolic and infectious diseases during the periparturient period. A major contributing factor to increased health disorders is alterations in bovine immune mechanisms. Indeed, uncontrolled inflammation is a major contributing factor and a common link among several economically important infectious and metabolic diseases including mastitis, retained placenta, metritis, displaced abomasum, and ketosis. The nutritional status of dairy cows and the metabolism of specific nutrients are critical regulators of immune cell function. There is now a greater appreciation that certain mediators of the immune system can have a reciprocal effect on the metabolism of nutrients. Thus, any disturbances in nutritional or immunological homeostasis can provide deleterious feedback loops that can further enhance health disorders, increase production losses, and decrease the availability of safe and nutritious dairy foods for a growing global population. This review will discuss the complex interactions between nutrient metabolism and immune functions in periparturient dairy cattle. Details of how either deficiencies or overexposure to macro- and micronutrients can contribute to immune dysfunction and the subsequent development of health disorders will be presented. Specifically, the ways in which altered nutrient metabolism and oxidative stress can interact to compromise the immune system in transition cows will be discussed. A better understanding of the linkages between nutrition and immunity may facilitate the design of nutritional regimens that will reduce disease susceptibility in early lactation cows. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Atmospheric CO2 enrichment and reactive nitrogen inputs interactively stimulate soil cation losses and acidification.

PubMed

Zhang, Li; Qiu, Yunpeng; Cheng, Lei; Wang, Yi; Liu, Lingli; Tu, Cong; Bowman, Dan C; Burkey, Kent O; Bian, Xinmin; Zhang, Weijian; Hu, Shuijin

2018-05-17

Reactive N inputs (Nr) may alleviate N-limitation of plant growth and are assumed to help sustain plant responses to the rising atmospheric CO2 (eCO2). However, Nr and eCO2 may elicit a cascade reaction that alters soil chemistry and nutrient availability, shifting the limiting factors of plant growth, particularly in acidic tropical and subtropical croplands with low organic matter and low nutrient cations. Yet, few have so far examined the interactive effects of Nr and eCO2 on the dynamics of soil cation nutrients and soil acidity. We investigated the cation dynamics in the plant-soil system with exposure to eCO2 and different N sources in a subtropical, acidic agricultural soil. eCO2 and Nr, alone and interactively, increased Ca2+ and Mg2+ in soil solutions or leachates in aerobic agroecosystems. eCO2 significantly reduced soil pH, and NH4+-N inputs amplified this effect, suggesting that eCO2-induced plant preference of NH4+-N and plant growth may facilitate soil acidification. This is, to our knowledge, the first direct demonstration of eCO2 enhancement of soil acidity, although other studies have previously shown that eCO2 can increase cation release into soil solutions. Together, these findings provide new insights into the dynamics of cation nutrients and soil acidity under future climatic scenarios, highlighting the urgency for more studies on plant-soil responses to climate change in acidic tropical and subtropical ecosystems.

Soil Nutrient Assessment for Urban Ecosystems in Hubei, China

PubMed Central

Li, Zhi-guo; Zhang, Guo-shi; Liu, Yi; Wan, Kai-yuan; Zhang, Run-hua; Chen, Fang

2013-01-01

Recent urban landscape vegetation surveys conducted in many cities in China identified numerous plant nutrient deficiencies, especially in newly developed cities. Soil nutrients and soil nutrient management in the cities of Hubei province have not received adequate attention to date. The aims of this study were to characterize the available nutrients of urban soils from nine cities in Hubei province, China, and to assess how soil nutrient status is related to land use type and topography. Soil nutrients were measured in 405 sites from 1,215 soil samples collected from four land use types (park, institutional [including government building grounds, municipal party grounds, university grounds, and garden city institutes], residential, and roadside verges) and three topographies (mountainous [142–425 m a.s.l], hilly [66–112 m a.s.l], and plain [26–30 m a.s.l]). Chemical analyses showed that urban soils in Hubei had high pH and lower soil organic matter, available nitrogen (N), available phosphorus (P), and available boron (B) concentrations than natural soils. Nutrient concentrations were significantly different among land use types, with the roadside and residential areas having greater concentrations of calcium (Ca), sulfur (S), copper (Cu), manganese (Mn), and zinc (Zn) that were not deficient against the recommended ranges. Topographic comparisons showed statistically significant effects for 8 of the 11 chemical variables (p < 0.05). Concentrations of N, Ca, Mg, S, Cu, and Mn in plain cities were greater than those in mountainous cities and show a negative correlation with city elevation. These results provide data on urban soils characteristics in land use types and topography, and deliver significant information for city planners and policy makers. PMID:24086647

Soil nutrient assessment for urban ecosystems in Hubei, China.

PubMed

Li, Zhi-Guo; Zhang, Guo-Shi; Liu, Yi; Wan, Kai-Yuan; Zhang, Run-Hua; Chen, Fang

2013-01-01

Recent urban landscape vegetation surveys conducted in many cities in China identified numerous plant nutrient deficiencies, especially in newly developed cities. Soil nutrients and soil nutrient management in the cities of Hubei province have not received adequate attention to date. The aims of this study were to characterize the available nutrients of urban soils from nine cities in Hubei province, China, and to assess how soil nutrient status is related to land use type and topography. Soil nutrients were measured in 405 sites from 1,215 soil samples collected from four land use types (park, institutional [including government building grounds, municipal party grounds, university grounds, and garden city institutes], residential, and roadside verges) and three topographies (mountainous [142-425 m a.s.l], hilly [66-112 m a.s.l], and plain [26-30 m a.s.l]). Chemical analyses showed that urban soils in Hubei had high pH and lower soil organic matter, available nitrogen (N), available phosphorus (P), and available boron (B) concentrations than natural soils. Nutrient concentrations were significantly different among land use types, with the roadside and residential areas having greater concentrations of calcium (Ca), sulfur (S), copper (Cu), manganese (Mn), and zinc (Zn) that were not deficient against the recommended ranges. Topographic comparisons showed statistically significant effects for 8 of the 11 chemical variables (p < 0.05). Concentrations of N, Ca, Mg, S, Cu, and Mn in plain cities were greater than those in mountainous cities and show a negative correlation with city elevation. These results provide data on urban soils characteristics in land use types and topography, and deliver significant information for city planners and policy makers.

The influence of soil properties and nutrients on conifer forest growth in Sweden, and the first steps in developing a nutrient availability metric

NASA Astrophysics Data System (ADS)

Van Sundert, Kevin; Horemans, Joanna A.; Stendahl, Johan; Vicca, Sara

2018-06-01

The availability of nutrients is one of the factors that regulate terrestrial carbon cycling and modify ecosystem responses to environmental changes. Nonetheless, nutrient availability is often overlooked in climate-carbon cycle studies because it depends on the interplay of various soil factors that would ideally be comprised into metrics applicable at large spatial scales. Such metrics do not currently exist. Here, we use a Swedish forest inventory database that contains soil data and tree growth data for > 2500 forests across Sweden to (i) test which combination of soil factors best explains variation in tree growth, (ii) evaluate an existing metric of constraints on nutrient availability, and (iii) adjust this metric for boreal forest data. With (iii), we thus aimed to provide an adjustable nutrient metric, applicable for Sweden and with potential for elaboration to other regions. While taking into account confounding factors such as climate, N deposition, and soil oxygen availability, our analyses revealed that the soil organic carbon concentration (SOC) and the ratio of soil carbon to nitrogen (C : N) were the most important factors explaining variation in normalized (climate-independent) productivity (mean annual volume increment - m3 ha-1 yr-1) across Sweden. Normalized forest productivity was significantly negatively related to the soil C : N ratio (R2 = 0.02-0.13), while SOC exhibited an empirical optimum (R2 = 0.05-0.15). For the metric, we started from a (yet unvalidated) metric for constraints on nutrient availability that was previously developed by the International Institute for Applied Systems Analysis (IIASA - Laxenburg, Austria) for evaluating potential productivity of arable land. This IIASA metric requires information on soil properties that are indicative of nutrient availability (SOC, soil texture, total exchangeable bases - TEB, and pH) and is based on theoretical considerations that are also generally valid for nonagricultural ecosystems. However, the IIASA metric was unrelated to normalized forest productivity across Sweden (R2 = 0.00-0.01) because the soil factors under consideration were not optimally implemented according to the Swedish data, and because the soil C : N ratio was not included. Using two methods (each one based on a different way of normalizing productivity for climate), we adjusted this metric by incorporating soil C : N and modifying the relationship between SOC and nutrient availability in view of the observed relationships across our database. In contrast to the IIASA metric, the adjusted metrics explained some variation in normalized productivity in the database (R2 = 0.03-0.21; depending on the applied method). A test for five manually selected local fertility gradients in our database revealed a significant and stronger relationship between the adjusted metrics and productivity for each of the gradients (R2 = 0.09-0.38). This study thus shows for the first time how nutrient availability metrics can be evaluated and adjusted for a particular ecosystem type, using a large-scale database.

Scaling of physical constraints at the root-soil interface to macroscopic patterns of nutrient retention in ecosystems.

PubMed

Gerber, Stefan; Brookshire, E N Jack

2014-03-01

Nutrient limitation in terrestrial ecosystems is often accompanied with maintaining a nearly closed vegetation-soil nutrient cycle. The ability to retain nutrients in an ecosystem requires the capacity of the plant-soil system to draw down nutrient levels in soils effectually such that export concentrations in soil solutions remain low. Here we address the physical constraints of plant nutrient uptake that may be limited by the diffusive movement of nutrients in soils, by the uptake at the root/mycorrhizal surface, and from interactions with soil water flow. We derive an analytical framework of soil nutrient transport and uptake and predict levels of plant available nutrient concentration and residence time. Our results, which we evaluate for nitrogen, show that the physical environment permits plants to lower soil solute concentration substantially. Our analysis confirms that plant uptake capacities in soils are considerable, such that water movement in soils is generally too small to significantly erode dissolved plant-available nitrogen. Inorganic nitrogen concentrations in headwater streams are congruent with the prediction of our theoretical framework. Our framework offers a physical-based parameterization of nutrient uptake in ecosystem models and has the potential to serve as an important tool toward scaling biogeochemical cycles from individual roots to landscapes.

Bamboo shoot preservation for enhancing its business potential and local economy: a review.

PubMed

Bal, Lalit M; Singhal, Poonam; Satya, Santosh; Naik, S N; Kar, Abhijit

2012-01-01

Bamboo shoot as food has been used in traditional ways by the tribal community the world over. For enhancing its business potential, research on various aspects of bamboo shoot as food is being carried out in Japan, Taiwan, Thailand, and Asian countries and several products are available in the market. Bamboo shoots are used as a delicacy in human food, are a good source of dietary fiber, low in fat and calories. The research studies included in this review paper focus on post-harvest preservation of bamboo shoot. In view of the seasonal availability of bamboo shoot, the post-harvest preservation system for handling cynogenic toxicity in raw shoot while keeping nutrients intact and enhancement of shelf life of the value added products assume great significance for the business potential of this natural product. A yardstick of assessing the "Shelf life-Quality Matrix" developed in this review paper would give a new perspective of quality control in case of preservation of bamboo shoot. Also, knowledge gaps identified in this paper would give impetus to new academic and R&D activities, in turn generating an innovative job profile in the food industry as well as rural entrepreneurship.

Variations in eco-enzymatic stoichiometric and microbial characteristics in paddy soil as affected by long-term integrated organic-inorganic fertilization

PubMed Central

Lin, Sen; Wang, Shaoxian; Si, Yuanli; Yang, Wenhao; Zhu, Shaowei

2017-01-01

To investigate the effects of different nutrient management regimes on the soil chemical, eco-enzymatic stoichiometric and microbial characteristics, soil samples were collected from a 30-year, long-term field experiment with six plots growing rice. The results showed that as integrated fertilization increased, so did the concentrations of soil total or available nutrients and microbial biomass carbon (MBC). Our results also found enhanced soil basal respiration and cumulative carbon mineralization compared to chemical fertilization alone at the same nutrient doses. The activities of soil protease (Pro), β-glucosidase (βG), N-acetyl-glucosaminidase (NAG) and acid phosphatase (AP) from the integrated fertilization treatments were significantly higher than those of the treatments without organic manure, so did the activities of soil leucyl aminopeptidase (LAP) and urease (Ure) from the treatment with organic manure in addition to farmer practise fertilization (NPKM2). The stoichiometric ratios, expressed as lnβG/ln(NAG+LAP)/lnPro/lnUre/lnAP, ranged from 1:0.94:1.04:0.67:1.01 to 1:0.98:1.10:0.78:1.25, indicating that the acquisition of C, N and P changed consistently and synchronously under different nutrient management strategies. Integrated fertilization was more beneficial to the acquisition and utilization of soil organic carbon compared to low-molecular-weight organic nitrogen. We concluded that protease and urease should be considered in eco-enzymatic stoichiometric assessments for the hydrolysis of proteins, amino acids, carbohydrates and phosphomonoesters in soil, and integrated fertilization with chemical fertilizers and organic manure should be recommended as a preferable nutrient management system for intensive rice cultivation. PMID:29253000

Multifunctional Nutrient-Binding Proteins Adapt Human Symbiotic Bacteria for Glycan Competition in the Gut by Separately Promoting Enhanced Sensing and Catalysis

PubMed Central

Cameron, Elizabeth A.; Kwiatkowski, Kurt J.; Lee, Byung-Hoo; Hamaker, Bruce R.; Koropatkin, Nicole M.

2014-01-01

ABSTRACT To compete for the dynamic stream of nutrients flowing into their ecosystem, colonic bacteria must respond rapidly to new resources and then catabolize them efficiently once they are detected. The Bacteroides thetaiotaomicron starch utilization system (Sus) is a model for nutrient acquisition by symbiotic gut bacteria, which harbor thousands of related Sus-like systems. Structural investigation of the four Sus outer membrane proteins (SusD, -E, -F, and -G) revealed that they contain a total of eight starch-binding sites that we demonstrated, using genetic and biochemical approaches, to play distinct roles in starch metabolism in vitro and in vivo in gnotobiotic mice. SusD, whose homologs are abundant in the human microbiome, is critical for the initial sensing of available starch, allowing sus transcriptional activation at much lower concentrations than without this function. In contrast, seven additional binding sites across SusE, -F, and -G are dispensable for sus activation. However, they optimize the rate of growth on starch in a manner dependent on the expression of the bacterial polysaccharide capsule, suggesting that they have evolved to offset the diffusion barrier created by this structure. These findings demonstrate how proteins with similar biochemical behavior can serve orthogonal functions during different stages of cellular adaptation to nutrients. Finally, we demonstrated in gnotobiotic mice fed a starch-rich diet that the Sus binding sites confer a competitive advantage to B. thetaiotaomicron in vivo in a manner that is dependent on other colonizing microbes. This study reveals how numerically dominant families of carbohydrate-binding proteins in the human microbiome fulfill separate and sometimes cooperative roles to optimize gut commensal bacteria for nutrient acquisition. PMID:25205092

Inoculant of Arbuscular Mycorrhizal Fungi (Rhizophagus clarus) Increase Yield of Soybean and Cotton under Field Conditions.

PubMed

Cely, Martha V T; de Oliveira, Admilton G; de Freitas, Vanessa F; de Luca, Marcelo B; Barazetti, André R; Dos Santos, Igor M O; Gionco, Barbara; Garcia, Guilherme V; Prete, Cássio E C; Andrade, Galdino

2016-01-01

Nutrient availability is an important factor in crop production, and regular addition of chemical fertilizers is the most common practice to improve yield in agrosystems for intensive crop production. The use of some groups of microorganisms that have specific activity providing nutrients to plants is a good alternative, and arbuscular mycorrhizal fungi (AMF) enhance plant nutrition by providing especially phosphorus, improving plant growth and increasing crop production. Unfortunately, the use of AMF as an inoculant on a large scale is not yet widely used, because of several limitations in obtaining a large amount of inoculum due to several factors, such as low growth, the few species of AMF domesticated under in vitro conditions, and high competition with native AMF. The objective of this work was to test the infectivity of a Rhizophagus clarus inoculum and its effectiveness as an alternative for nutrient supply in soybean (Glycine max L.) and cotton (Gossypium hirsutum L.) when compared with conventional chemical fertilization under field conditions. The experiments were carried out in a completely randomized block design with five treatments: Fertilizer, AMF, AMF with Fertilizer, AMF with 1/2 Fertilizer, and the Control with non-inoculated and non-fertilized plants. The parameters evaluated were AMF root colonization and effect of inoculation on plant growth, nutrient absorption and yield. The results showed that AMF inoculation increased around 20 % of root colonization in both soybean and cotton; nutrients analyses in vegetal tissues showed increase of P and nitrogen content in inoculated plants, these results reflect in a higher yield. Our results showed that, AMF inoculation increase the effectiveness of fertilizer application in soybean and reduce the fertilizer dosage in cotton.

The Role of Nutrients in Protecting Mitochondrial Function and Neurotransmitter Signaling: Implications for the Treatment of Depression, PTSD, and Suicidal Behaviors.

PubMed

Du, Jing; Zhu, Ming; Bao, Hongkun; Li, Bai; Dong, Yilong; Xiao, Chunjie; Zhang, Grace Y; Henter, Ioline; Rudorfer, Matthew; Vitiello, Benedetto

2016-11-17

Numerous studies have linked severe stress to the development of major depressive disorder (MDD) and suicidal behaviors. Furthermore, recent preclinical studies from our laboratory and others have demonstrated that in rodents, chronic stress and the stress hormone cortisol cause oxidative damage to mitochondrial function and membrane lipids in the brain. Mitochondria play a key role in synaptic neurotransmitter signaling by providing adenosine triphosphate (ATP), mediating lipid and protein synthesis, buffering intracellular calcium, and regulating apoptotic and resilience pathways. Membrane lipids are similarly essential to central nervous system (CNS) function because cholesterol, polyunsaturated fatty acids, and sphingolipids form a lipid raft region, a special lipid region on the membrane that mediates neurotransmitter signaling through G-protein-coupled receptors and ion channels. Low serum cholesterol levels, low antioxidant capacity, and abnormal early morning cortisol levels are biomarkers consistently associated with both depression and suicidal behaviors. In this review, we summarize the manner in which nutrients can protect against oxidative damage to mitochondria and lipids in the neuronal circuits associated with cognitive and affective behaviors. These nutrients include ω3 fatty acids, antioxidants (vitamin C and zinc), members of the vitamin B family (Vitamin B12 and folic acid), and magnesium. Accumulating data have shown that these nutrients can enhance neurocognitive function, and may have therapeutic benefits for depression and suicidal behaviors. A growing body of studies suggests the intriguing possibility that regular consumption of these nutrients may help prevent the onset of mood disorders and suicidal behaviors in vulnerable individuals, or significantly augment the therapeutic effect of available antidepressants. These findings have important implications for the health of both military and civilian populations.

Rationale and clinical data supporting nutritional intervention in Alzheimer's disease.

PubMed

Engelborghs, S; Gilles, C; Ivanoiu, A; Vandewoude, M

2014-01-01

Adequate nutrition plays an important role in the maintenance of cognitive function, particularly during aging. Malnutrition is amongst the risk factors for developing mild cognitive impairment (MCI) and Alzheimer's disease (AD). Epidemiological studies have associated deficiencies in some nutrients with a higher risk of cognitive dysfunction and/or AD. Cognitive decline in AD is correlated with synaptic loss and many of the components required to maintain optimal synaptic function are derived from dietary sources. As synapses are part of the neuronal membrane and are continuously being remodelled, the availability of sufficient levels of nutritional precursors (mainly uridine monophosphate, choline and omega-3 fatty acids) to make the phospholipids required to build neuronal membranes may have beneficial effects on synaptic degeneration in AD. In addition, B-vitamins, phospholipids and other micronutrients act as cofactors to enhance the supply of precursors required to make neuronal membranes and synapses. Despite this, no randomized controlled trial has hitherto provided evidence that any single nutrient has a beneficial effect on cognition or lowers the risk for AD. However, a multi-target approach using combinations of (micro)nutrients might have beneficial effects on cognitive function in neurodegenerative brain disorders like AD leading to synaptic degeneration. Here we review the clinical evidence for supplementation, based on a multi-target approach with a focus on key nutrients with a proposed role in synaptic dysfunction. Based on preclinical evidence, a nutrient mixture, Souvenaid(®) (Nutricia N.V., Zoetermeer, The Netherlands) was developed. Clinical trials with Souvenaid(®) have shown improved memory performance in patients with mild AD. Further clinical trials to evaluate the effects of nutritional intervention in MCI and early dementia due to AD are on-going.

The Role of Nutrients in Protecting Mitochondrial Function and Neurotransmitter Signaling: Implications for the Treatment of Depression, PTSD, and Suicidal Behaviors

PubMed Central

Du, Jing; Zhu, Ming; Bao, Hongkun; Li, Bai; Dong, Yilong; Xiao, Chunjie; Zhang, Grace Y.; Henter, Ioline; Rudorfer, Matthew; Vitiello, Benedetto

2015-01-01

Numerous studies have linked severe stress to the development of major depressive disorder (MDD), and suicidal behaviors. Furthermore, recent preclinical studies from our laboratory and others have demonstrated that in rodents, chronic stress and the stress hormone cortisol has caused oxidative damage to mitochondrial function and membrane lipids in the brain. Mitochondria play a key role in synaptic neurotransmitter signaling by providing adenosine triphosphate (ATP), mediating lipid and protein synthesis, buffering intracellular calcium, and regulating apoptotic and resilience pathways. Membrane lipids are similarly essential to central nervous system (CNS) function, because cholesterol, polyunsaturated fatty acids, and sphingolipids form a lipid raft region, a special lipid region on the membrane that mediates neurotransmitter signaling through G-protein coupled receptors and ion channels. Low serum cholesterol levels, low antioxidant capacity, and abnormal early morning cortisol levels are biomarkers consistently associated with both depression and suicidal behaviors. In this review, we summarize the manner in which nutrients can protect against oxidative damage to mitochondria and lipids in the neuronal circuits associated with cognitive and affective behaviors. These nutrients include ω3 fatty acids, antioxidants (vitamin C and zinc), members of the vitamin B family (Vitamin B12 and folic acid) and magnesium. Accumulating data have shown that these nutrients can enhance neurocognitive function, and may have therapeutic benefits for depression and suicidal behaviors. A growing body of studies suggests the intriguing possibility that regular consumption of these nutrients may help prevent the onset of mood disorders and suicidal behaviors in vulnerable individuals, or significantly augment the therapeutic effect of available antidepressants. These findings have important implications for the health of both military and civilian populations. PMID:25365455

Variations in eco-enzymatic stoichiometric and microbial characteristics in paddy soil as affected by long-term integrated organic-inorganic fertilization.

PubMed

Lin, Sen; Wang, Shaoxian; Si, Yuanli; Yang, Wenhao; Zhu, Shaowei; Ni, Wuzhong

2017-01-01

To investigate the effects of different nutrient management regimes on the soil chemical, eco-enzymatic stoichiometric and microbial characteristics, soil samples were collected from a 30-year, long-term field experiment with six plots growing rice. The results showed that as integrated fertilization increased, so did the concentrations of soil total or available nutrients and microbial biomass carbon (MBC). Our results also found enhanced soil basal respiration and cumulative carbon mineralization compared to chemical fertilization alone at the same nutrient doses. The activities of soil protease (Pro), β-glucosidase (βG), N-acetyl-glucosaminidase (NAG) and acid phosphatase (AP) from the integrated fertilization treatments were significantly higher than those of the treatments without organic manure, so did the activities of soil leucyl aminopeptidase (LAP) and urease (Ure) from the treatment with organic manure in addition to farmer practise fertilization (NPKM2). The stoichiometric ratios, expressed as lnβG/ln(NAG+LAP)/lnPro/lnUre/lnAP, ranged from 1:0.94:1.04:0.67:1.01 to 1:0.98:1.10:0.78:1.25, indicating that the acquisition of C, N and P changed consistently and synchronously under different nutrient management strategies. Integrated fertilization was more beneficial to the acquisition and utilization of soil organic carbon compared to low-molecular-weight organic nitrogen. We concluded that protease and urease should be considered in eco-enzymatic stoichiometric assessments for the hydrolysis of proteins, amino acids, carbohydrates and phosphomonoesters in soil, and integrated fertilization with chemical fertilizers and organic manure should be recommended as a preferable nutrient management system for intensive rice cultivation.

Nutritional Modulation of Age-Related Macular Degeneration

PubMed Central

Weikel, Karen A; Taylor, Allen

2012-01-01

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly worldwide. It affects 30–50 million individuals and clinical hallmarks of AMD are observed in at least one third of persons over the age of 75 in industrialized countries (Gehrs et al., 2006). Costs associated with AMD are in excess of $340 billion US (American-Health-Assistance-Foundation, 2012). The majority of AMD patients in the United States are not eligible for clinical treatments (Biarnes et al., 2011; Klein et al., 2011). Preventive interventions through dietary modulation are attractive strategies because many studies suggest a benefit of micro and macronutrients with respect to AMD, as well as other age-related debilities, and with few, if any, adverse effects (Chiu, 2011). Preservation of vision would enhance quality of life for millions of elderly people, and alleviate the personal and public health financial burden of AMD (Frick et al., 2007; Wood et al., 2011). Observational studies indicate that maintaining adequate levels of omega-3 fatty acids (i.e. with 2 servings/wk of fish) or a low glycemic index diet may be particularly beneficial for early AMD and that higher levels of carotenoids may be protective, most probably, against neovascular AMD. Intervention trials are needed to better understand the full effect of these nutrients and/or combinations of nutrients on retinal health. Analyses that describe effects of a nutrient on onset and/or progress of AMD are valuable because they indicate the value of a nutrient to arrest AMD at the early stages. This comprehensive summary provides essential information about the value of nutrients with regard to diminishing risk for onset or progress of AMD and can serve as a guide until data from ongoing intervention trials are available. PMID:22503690

Effects of nutrient content claims, sports celebrity endorsements and premium offers on pre-adolescent children's food preferences: experimental research.

PubMed

Dixon, H; Scully, M; Niven, P; Kelly, B; Chapman, K; Donovan, R; Martin, J; Baur, L A; Crawford, D; Wakefield, M

2014-04-01

To assess pre-adolescent children's responses to common child-oriented front-of-pack food promotions. Between-subjects, web-based experiment with four front-of-pack promotion conditions on energy-dense and nutrient-poor (EDNP) foods: no promotion [control]; nutrient content claims; sports celebrity endorsements (male athletes) and premium offers. Participants were 1302 grade 5 and 6 children (mean age 11 years) from Melbourne, Australia. Participants chose their preferred product from a randomly assigned EDNP food pack and comparable healthier food pack then completed detailed product ratings. Child-oriented pack designs with colourful, cartooned graphics, fonts and promotions were used. Compared to the control condition, children were more likely to choose EDNP products featuring nutrient content claims (both genders) and sports celebrity endorsements (boys only). Perceptions of nutritional content were enhanced by nutrient content claims. Effects of promotions on some product ratings (but not choice) were negated when children referred to the nutrition information panel. Premium offers did not enhance children's product ratings or choice. Nutrient content claims and sports celebrity endorsements influence pre-adolescent children's preferences towards EDNP food products displaying them. Policy interventions to reduce the impact of unhealthy food marketing to children should limit the use of these promotions. © 2013 The Authors. Pediatric Obesity © 2013 International Association for the Study of Obesity.

Agronomic assessment of pyrolysed food waste digestate for sandy soil management.

PubMed

Opatokun, Suraj Adebayo; Yousef, Lina F; Strezov, Vladimir

2017-02-01

The digestate (DFW) of an industrial food waste treatment plant was pyrolysed for production of biochar for its direct application as bio-fertilizer or soil enhancer. Nutrient dynamics and agronomic viability of the pyrolysed food waste digestate (PyD) produced at different temperatures were evaluated using germination index (GI), water retention/availability and mineral sorption as indicators when applied on arid soil. The pyrolysis was found to enrich P, K and other micronutrients in the biochar at an average enrichment factor of 0.87. All PyD produced at different temperatures indicated significantly low phytotoxicity with GI range of 106-168% and an average water retention capacity of 40.2%. Differential thermogravimetric (DTG) thermographs delineated the stability of the food waste digestate pyrolysed at 500 °C (PyD500) against the degradation of the digestate food waste despite the latter poor nutrient sorption potential. Plant available water in soil is 40% when treated with 100 g of digestate per kg soil, whereas PyD500 treated soil indicated minimal effect on plant available water, even with high application rates. However, the positive effects of PyD on GI and the observed enrichment in plant macro and micronutrients suggest potential agronomic benefits for PyD use, in addition to the benefits from energy production from DFW during the pyrolysis process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metallic Nanoparticle (TiO2 and Fe3O4) Application Modifies Rhizosphere Phosphorus Availability and Uptake by Lactuca sativa.

PubMed

Zahra, Zahra; Arshad, Muhammad; Rafique, Rafia; Mahmood, Arshad; Habib, Amir; Qazi, Ishtiaq A; Khan, Saud A

2015-08-12

Application of engineered nanoparticles (NPs) with respect to nutrient uptake in plants is not yet well understood. The impacts of TiO2 and Fe3O4 NPs on the availability of naturally soil-bound inorganic phosphorus (Pi) to plants were studied along with relevant parameters. For this purpose, Lactuca sativa (lettuce) was cultivated on the soil amended with TiO2 and Fe3O4 (0, 50, 100, 150, 200, and 250 mg kg(-1)) over a period of 90 days. Different techniques, such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Raman, and Fourier transform infrared spectroscopy (FTIR) were used to monitor translocation and understand the possible mechanisms for phosphorus (P) uptake. The trends for P accumulation were different for roots (TiO2 > Fe3O4 > control) and shoots (Fe3O4 > TiO2 > control). Cystine and methionine were detected in the rhizosphere in Raman spectra. Affinities of NPs to adsorb phosphate ions, modifications in P speciation, and NP stress in the rhizosphere had possibly contributed to enhanced root exudation and acidification. All of these changes led to improved P availability and uptake by the plants. These promising results can help to develop an innovative strategy for using NPs for improved nutrient management to ensure food security.

The stoichiometry of nutrient release by terrestrial herbivores and its ecosystem consequences

NASA Astrophysics Data System (ADS)

Sitters, Judith; Bakker, Elisabeth S.; Veldhuis, Michiel P.; Veen, G. F.; Olde Venterink, Harry; Vanni, Michael J.

2017-04-01

It is widely recognized that the release of nutrients by herbivores via their waste products strongly impacts nutrient availability for autotrophs. The ratios of nitrogen (N) and phosphorus (P) recycled through herbivore release (i.e., waste N:P) are mainly determined by the stoichiometric composition of the herbivore’s food (food N:P) and its body nutrient content (body N:P). Waste N:P can in turn impact autotroph nutrient limitation and productivity. Herbivore-driven nutrient recycling based on stoichiometric principles is dominated by theoretical and experimental research in freshwater systems, in particular interactions between algae and invertebrate herbivores. In terrestrial ecosystems, the impact of herbivores on nutrient cycling and availability is often limited to studying carbon (C ):N and C:P ratios, while the role of terrestrial herbivores in mediating N:P ratios is also likely to influence herbivore-driven nutrient recycling. In this review, we use rules and predictions on the stoichiometry of nutrient release originating from algal-based aquatic systems to identify the factors that determine the stoichiometry of nutrient release by herbivores. We then explore how these rules can be used to understand the stoichiometry of nutrient release by terrestrial herbivores, ranging from invertebrates to mammals, and its impact on plant nutrient limitation and productivity. Future studies should focus on measuring both N and P when investigating herbivore-driven nutrient recycling in terrestrial ecosystems, while also taking the form of waste product (urine or feces) and other pathways by which herbivores change nutrients into account, to be able to quantify the impact of waste stoichiometry on plant communities.

Systematic review to support the development of nutrient reference intake values: challenges and solutions

USDA-ARS?s Scientific Manuscript database

Workshops sponsored by the Institute of Medicine (IOM) and the World Health Organization (WHO) suggested that incorporating systematic reviews into the process of updating nutrient reference values would enhance the transparency of the process. The IOM issues the Dietary Reference Intake values (DR...

Corn grain and nutrient uptake response to different swine manure application methods

USDA-ARS?s Scientific Manuscript database

Farmers are looking for better management practices to enhance production and reduce negative environmental impact from nitrogen (N) fertilizer application since N is one of the most important and costly nutrient inputs for crop production. In this field experiment pre-plant swine effluent applicati...

Nitrogen source and application method impact on corn yield and nutrient uptake

USDA-ARS?s Scientific Manuscript database

Farmers are looking for better management practices to enhance production and reduce negative environmental impact from nitrogen (N) fertilizer application since N is one of the most important and costly nutrient inputs for crop production. In this field experiment pre-plant swine effluent applicati...

Cell-specific CO2 fixation rates of two distinct groups of plastidic protists in the Atlantic Ocean remain unchanged after nutrient addition.

PubMed

Grob, Carolina; Jardillier, Ludwig; Hartmann, Manuela; Ostrowski, Martin; Zubkov, Mikhail V; Scanlan, David J

2015-04-01

To assess the role of open-ocean ecosystems in global CO2 fixation, we investigated how picophytoplankton, which dominate primary production, responded to episodic increases in nutrient availability. Previous experiments have shown nitrogen alone, or in combination with phosphorus or iron, to be the proximate limiting nutrient(s) for total phytoplankton grown over several days. Much less is known about how nutrient upshift affects picophytoplankton CO2 fixation over the duration of the light period. To address this issue, we performed a series of small volume (8-60 ml) - short term (10-11 h) nutrient addition experiments in different regions of the Atlantic Ocean using NH4 Cl, FeCl3 , K medium, dust and nutrient-rich water from 300 m depth. We found no significant nutrient stimulation of group-specific CO2 fixation rates of two taxonomically and size-distinct groups of plastidic protists. The above was true regardless of the region sampled or nutrient added, suggesting that this is a generic phenomenon. Our findings show that at least in the short term (i.e. daylight period), nutrient availability does not limit CO2 fixation by the smallest plastidic protists, while their taxonomic composition does not determine their response to nutrient addition. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Assessing the Feasibility and Risks of Using Wave-Driven Upwelling Pumps to Enhance the Biological Sequestration of Carbon in Open Oceans

NASA Astrophysics Data System (ADS)

White, A.; Bjorkman, K.; Grabowski, E.; Letelier, R. M.; Poulos, S.; Watkins, B.; Karl, D. M.

2008-12-01

In 1976, John D. Isaacs proposed to use wave energy to pump cold and nutrient-rich deep water into the sunlit surface layers. The motivation for this endeavor has taken many forms over the years, from energy production to fueling aquaculture to the more recent suggestion that artificial upwelling could be used to stimulate primary productivity and anthropogenic carbon sequestration in oligotrophic regions of the ocean. However, the potential for biological carbon sequestration in response to upwelling will depend on the concentration of nutrients relative to that of dissolved inorganic carbon in the water being upwelled and on the response of the marine microbial assemblage to this nutrient enrichment. In June 2008, we tested a commercially available wave pump in the vicinity of Station ALOHA, north of Oahu, Hawaii in order to assess the logistics of at-sea deployment and the survivability of the equipment in the open ocean. Our engineering test was also designed to evaluate a recently published hypothesis (Karl and Letelier, 2008, Marine Ecology Progress Series) that upwelling of water containing excess phosphate relative to nitrogen compared to the canonical "Redfield" molar ratio of 16N:1P, would generate a two-phased phytoplankton bloom and enhance carbon sequestration. In this presentation, we analyze the results of this field test within the context of pelagic biogeochemical cycles. Furthermore, we discuss the deployment of a 300m wave pump, efforts to sample a biochemical response, the engineering challenges faced and the practical and ethical implications of these results for future experiments aimed at stimulating the growth of phytoplankton in oligotrophic regions.

A Ca(2)+ signaling pathway regulates a K(+) channel for low-K response in Arabidopsis.

PubMed

Li, Legong; Kim, Beom-Gi; Cheong, Yong Hwa; Pandey, Girdhar K; Luan, Sheng

2006-08-15

Nutrient sensing is critical for plant adaptation to the environment. Because of extensive farming and erosion, low content of mineral nutrients such as potassium (K(+)) in soils becomes a limiting factor for plant growth. In response to low-K conditions, plants enhance their capability of K(+) uptake through an unknown signaling mechanism. Here we report the identification of a Ca(2+)-dependent pathway for low-K response in Arabidopsis. We are not aware of any other example of a molecular pathway for a nutrient response in plants. Earlier genetic analyses revealed three genes encoding two Ca(2+) sensors (CBL1 and CBL9) and their target protein kinase (CIPK23) to be critical for plant growth on low-K media and for stomatal regulation, indicating that these calcium signaling components participate in the low-K response and turgor regulation. In this study, we show that the protein kinase CIPK23 interacted with, and phosphorylated, a voltage-gated inward K(+) channel (AKT1) required for K(+) acquisition in Arabidopsis. In the Xenopus oocyte system, our studies showed that interacting calcium sensors (CBL1 and CBL9) together with target kinase CIPK23, but not either component alone, activated the AKT1 channel in a Ca(2+)-dependent manner, connecting the Ca(2+) signal to enhanced K(+) uptake through activation of a K(+) channel. Disruption of both CBL1 and CBL9 or CIPK23 gene in Arabidopsis reduced the AKT1 activity in the mutant roots, confirming that the Ca(2+)-CBL-CIPK pathway functions to orchestrate transporting activities in planta according to external K(+) availability.

Effects of biochar on enhanced nutrient use efficiency of green bean, Vigna radiata L.

PubMed

Prapagdee, Songkrit; Tawinteung, Nukoon

2017-04-01

Biochar is the carbonized material produced from biomass and is used in several environmental applications. The biochar characteristics depend on the carbonization conditions and feedstock. The suitability of a given biochar for soil improvement depends on the biochar characteristics, soil properties, and target plants. Biochar has been applied at 1-20% (w/w) in the soil, but currently there is a lack of information on what type and concentration of biochar are most suitable for a specific plant and soil quality. Too much biochar will reduce plant growth because of the high alkalinity of biochar, which will cause long-term soil alkalinity. In contrast, too little biochar might be insufficient to enhance plant productivity. In this study, a suitable concentration of cassava stem (an abundant agricultural waste in Thailand) biochar produced at 350 °C was evaluated for green bean (Vigna radiata L.) growth from germination to seed production in pots over 8 weeks. The soil fertility was increased with increasing biochar concentration. At 5% (w/w) biochar, the soil fertility and plant growth were significantly enhanced, while 10% (w/w) biochar significantly enhanced bean growth and bean pod production. The increased biochar concentration in the soil significantly increased the soil total nitrogen and extractable potassium (K) levels but did not affect the amount of available phosphorous. Biochar at 10% (w/w) significantly induced the accumulation of K in the stems, leaves, nut shells, and roots but not in nut seeds. Moreover, biochar not only increased the K concentration in soil but also increased the plant nutrient use efficiency of K, which is important for plant growth. Graphical abstract ᅟ.

Relative importance of P and N in macrophyte and epilithic algae biomass in a wastewater-impacted oligotrophic river.

PubMed

Taube, Nadine; He, Jianxun; Ryan, M Cathryn; Valeo, Caterina

2016-08-01

The role of nutrient loading on biomass growth in wastewater-impacted rivers is important in order to effectively optimize wastewater treatment to avoid excessive biomass growth in the receiving water body. This paper directly relates wastewater treatment plant (WWTP) effluent nutrients (including ammonia (NH3-N), nitrate (NO3-N) and total phosphorus (TP)) to the temporal and spatial distribution of epilithic algae and macrophyte biomass in an oligotrophic river. Annual macrophyte biomass, epilithic algae data and WWTP effluent nutrient data from 1980 to 2012 were statistically analysed. Because discharge can affect aquatic biomass growth, locally weighted scatterplot smoothing (LOWESS) was used to remove the influence of river discharge from the aquatic biomass (macrophytes and algae) data before further analysis was conducted. The results from LOWESS indicated that aquatic biomass did not increase beyond site-specific threshold discharge values in the river. The LOWESS-estimated biomass residuals showed a variable response to different nutrients. Macrophyte biomass residuals showed a decreasing trend concurrent with enhanced nutrient removal at the WWTP and decreased effluent P loading, whereas epilithic algae biomass residuals showed greater response to enhanced N removal. Correlation analysis between effluent nutrient concentrations and the biomass residuals (both epilithic algae and macrophytes) suggested that aquatic biomass is nitrogen limited, especially by NH3-N, at most sampling sites. The response of aquatic biomass residuals to effluent nutrient concentrations did not change with increasing distance to the WWTP but was different for P and N, allowing for additional conclusions about nutrient limitation in specific river reaches. The data further showed that the mixing process between the effluent and the river has an influence on the spatial distribution of biomass growth.

Enhanced flavor-nutrient conditioning in obese rats on a high-fat, high-carbohydrate choice diet.

PubMed

Wald, Hallie S; Myers, Kevin P

2015-11-01

Through flavor-nutrient conditioning rats learn to prefer and increase their intake of flavors paired with rewarding, postingestive nutritional consequences. Since obesity is linked to altered experience of food reward and to perturbations of nutrient sensing, we investigated flavor-nutrient learning in rats made obese using a high fat/high carbohydrate (HFHC) choice model of diet-induced obesity (ad libitum lard and maltodextrin solution plus standard rodent chow). Forty rats were maintained on HFHC to induce substantial weight gain, and 20 were maintained on chow only (CON). Among HFHC rats, individual differences in propensity to weight gain were studied by comparing those with the highest proportional weight gain (obesity prone, OP) to those with the lowest (obesity resistant, OR). Sensitivity to postingestive food reward was tested in a flavor-nutrient conditioning protocol. To measure initial, within-meal stimulation of flavor acceptance by post-oral nutrient sensing, first, in sessions 1-3, baseline licking was measured while rats consumed grape- or cherry-flavored saccharin accompanied by intragastric (IG) water infusion. Then, in the next three test sessions they received the opposite flavor paired with 5 ml of IG 12% glucose. Finally, after additional sessions alternating between the two flavor-infusion contingencies, preference was measured in a two-bottle choice between the flavors without IG infusions. HFHC-OP rats showed stronger initial enhancement of intake in the first glucose infusion sessions than CON or HFHC-OR rats. OP rats also most strongly preferred the glucose-paired flavor in the two-bottle choice. These differences between OP versus OR and CON rats suggest that obesity is linked to responsiveness to postoral nutrient reward, consistent with the view that flavor-nutrient learning perpetuates overeating in obesity. Copyright © 2015 Elsevier Inc. All rights reserved.

Modeling the impact of hydraulic redistribution on the carbon flux and storages using CLM4.5 at four AmeriFlux Sites

NASA Astrophysics Data System (ADS)

Fu, C.; Wang, G.; Cardon, Z. G.

2015-12-01

Effects of hydraulic redistribution (HR) on the hydrological cycle and ecosystem dynamics have been demonstrated in the field, but few modeling studies have compared HR's influences on the carbon cycle in different ecosystems and climate regions. The soil moisture changes associated with HR could influence plant carbon gain via two mechanisms: (1) improved plant water status supporting stomatal opening, and/or (2) enhanced nutrient availability to plants caused by enhanced soil microbial activity. In this study, using a modified version of the Community Land Model with Century-based soil carbon pool kinetics that includes the "Ryel et al. 2002" scheme for hydraulic redistribution (HR), the influence of HR on the carbon flux and storage is investigated at four Ameriflux sites where HR was detected from soil moisture measurements. The study sites include a Douglas-fir site (US-Wrc) in Washington State with a mediterranean climate, a savanna site (US-SRM) in Arizona with a semi-arid climate, an oak/pine forest site (US-SCf) in Southern California with a mediterranean climate, and an evergreen broadleaf forest site (BR-Sa1) with tropical monsoon climate. Simulations revealed that HR tended to enhance plant growth at all four sites, and incorporating HR into CLM4.5 reduces the temporal fluctuation of soil carbon storage at all four sites. Simulations with HR can capture the net carbon exchange between ecosystem and the atmosphere (NEE) at the US-Wrc, US-SRM, and BR-Sa1 sites over the annual cycle. Incorporation of HR into CLM4.5 clearly improved the weekly and sub-daily NEE simulation during dry periods at US-SCf and BR-Sa1 site. HR-induced increase in Net Primary Productivity (NPP) at the US-Wrc and US-SRM sites was driven approximately equally by the two distinct mechanisms we investigated: increased stomatal conductance and increased nutrient availability to plants.

Can nutrient limitations explain low and declining white spruce growth near the Arctic treeline in the eastern Brooks Range, Alaska?

NASA Astrophysics Data System (ADS)

Ellison, S.; Sullivan, P. F.

2014-12-01

The position of the Arctic treeline is of critical importance for global carbon cycling and surface energy budgets. However, controls on tree growth at treeline remain uncertain. In the Alaskan Brooks Range, 20th century warming has caused varying growth responses among treeline trees, with trees in the west responding positively, while trees in the east have responded negatively. The prevailing explanation of this trend ascribes the negative growth response to warming-induced drought stress in the eastern Brooks Range. However, recent measurements of carbon isotope discrimination in tree rings, xylem sap flow and needle gas exchange suggest that drought stress cannot explain these regional growth declines. Additionally, evidence from the western Brooks Range suggests that nutrient availability, rather than drought stress, may be the proximate control on tree growth. In this study, we investigated the hypothesis that low and declining growth of eastern Brooks Range trees is due to low and declining soil nutrient availability, which may continue to decrease with climate change as soils become drier and microbial activity declines. We compared microclimate, tree performance, and a wide range of proxies for soil nutrient availability in four watersheds along a west-east transect in the Brooks Range during the growing seasons of 2013 and 2014. We hypothesized that soil nutrient availability would track closely with the strong west-east precipitation gradient, with higher rainfall and greater soil nutrient availability in the western Brooks Range. We expected to find that soil water contents in the west are near optimum for nitrogen mineralization, while those in the east are below optimum. Needle nitrogen concentration, net photosynthesis, branch extension growth, and growth in the main stem are expected to decline with the hypothesized decrease in soil nutrient availability. The results of our study will elucidate the current controls on growth of trees near the Arctic treeline, enabling improved predictions of future treeline position and more accurate reconstructions of past climate.

Biochar affected by composting with farmyard manure.

PubMed

Prost, Katharina; Borchard, Nils; Siemens, Jan; Kautz, Timo; Séquaris, Jean-Marie; Möller, Andreas; Amelung, Wulf

2013-01-01

Biochar applications to soils can improve soil fertility by increasing the soil's cation exchange capacity (CEC) and nutrient retention. Because biochar amendment may occur with the applications of organic fertilizers, we tested to which extent composting with farmyard manure increases CEC and nutrient content of charcoal and gasification coke. Both types of biochar absorbed leachate generated during the composting process. As a result, the moisture content of gasification coke increased from 0.02 to 0.94 g g, and that of charcoal increased from 0.03 to 0.52 g g. With the leachate, the chars absorbed organic matter and nutrients, increasing contents of water-extractable organic carbon (gasification coke: from 0.09 to 7.00 g kg; charcoal: from 0.03 to 3.52 g kg), total soluble nitrogen (gasification coke: from not detected to 705.5 mg kg; charcoal: from 3.2 to 377.2 mg kg), plant-available phosphorus (gasification coke: from 351 to 635 mg kg; charcoal: from 44 to 190 mg kg), and plant-available potassium (gasification coke: from 6.0 to 15.3 g kg; charcoal: from 0.6 to 8.5 g kg). The potential CEC increased from 22.4 to 88.6 mmol kg for the gasification coke and from 20.8 to 39.0 mmol kg for the charcoal. There were little if any changes in the contents and patterns of benzene polycarboxylic acids of the biochars, suggesting that degradation of black carbon during the composting process was negligible. The surface area of the biochars declined during the composting process due to the clogging of micropores by sorbed compost-derived materials. Interactions with composting substrate thus enhance the nutrient loads but alter the surface properties of biochars. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Current perspective on assessing site of digestion in ruminants.

PubMed

Merchen, N R; Elizalde, J C; Drackley, J K

1997-08-01

The site of nutrient digestion in the gastrointestinal tract of ruminants affects nutrient availability and the nature of digestive end-products supplied to the host animal. Methods to study site of digestion in vivo provide a tool to obtain data that enhance the ability to interpret or predict animal responses to some feeding practices. Examples are discussed for which site of digestion data provided insights that might not have been evident from other approaches. The use of site of digestion techniques may provide interpretation regarding digestion of N by ruminants different from those derived from measurement of total tract N digestion. Site of digestion measurements have been particularly important in studying effects of heat processing of protein sources and in understanding the nature of digestion of N in high-quality, fresh forages. Moreover, site of digestion techniques have been instrumental in interpreting the influences of supplemental fat sources on ruminal digestion and ruminal biohydrogenation and small intestinal digestion of long-chain fatty acids.

Nutrient limitation and morphological plasticity of the carnivorous pitcher plant Sarracenia purpurea in contrasting wetland environments.

PubMed

Bott, Terry; Meyer, Gretchen A; Young, Erica B

2008-01-01

* Plasticity of leaf nutrient content and morphology, and macronutrient limitation were examined in the northern pitcher plant, Sarracenia purpurea subsp. purpurea, in relation to soil nutrient availability in an open, neutral pH fen and a shady, acidic ombrotrophic bog, over 2 yr following reciprocal transplantation of S. purpurea between the wetlands. * In both wetlands, plants were limited by nitrogen (N) but not phosphorus (P) (N content < 2% DW(-1), N : P < 14) but photosynthetic quantum yields were high (F(V)/F(M) > 0.79). Despite carnivory, leaf N content correlated with dissolved N availability to plant roots (leaf N vs , r(2) = 0.344, P < 0.0001); carnivorous N acquisition did not apparently overcome N limitation. * Following transplantation, N content and leaf morphological traits changed in new leaves to become more similar to plants in the new environment, reflecting wetland nutrient availability. Changes in leaf morphology were faster when plants were transplanted from fen to bog than from bog to fen, possibly reflecting a more stressful environment in the bog. * Morphological plasticity observed in response to changes in nutrient supply to the roots in natural habitats complements previous observations of morphological changes with experimental nutrient addition to pitchers.

Nutrient allocation among plant organs across 13 tree species in three Bornean rain forests with contrasting nutrient availabilities.

PubMed

Aoyagi, Ryota; Kitayama, Kanehiro

2016-07-01

Allocation of nitrogen (N) and phosphorus (P) among plant organs is an important factor regulating growth rate, which is a key ecological process associated with plant life-history strategies. However, few studies have explored how N and P investment in photosynthetic (leaves) and non-photosynthetic (stems and roots) organs changes in relation to depletion of each element. We investigated nutrient concentrations of plant organs in relation to whole-plant nutrient concentration (total nutrient weight per total biomass) as an index of nutrient status of each individual using the saplings of the 13 species in three tropical rain forests with contrasting N and P availabilities (tropical evergreen forests and tropical heath forests). We found a steeper decrease in foliar N concentration than foliar P concentration with decreasing whole-plant nutrient concentration. Moreover, the steeper decrease in foliar N concentration was associated with relatively stable N concentration in stems, and vice versa for P. We suggest that the depletion of N is associated with a rapid dilution of foliar N because the cell walls in non-photosynthetic organs function as an N sink. On the other hand, these species can maintain foliar P concentration by decreasing stem P concentrations despites the depletion of P. Our results emphasize the significance of non-photosynthetic organs as an N sink for understanding the variation of foliar nutrient concentrations for the tree species in the three Bornean rain forests with different N and P availabilities.

Biochar in viticulture

NASA Astrophysics Data System (ADS)

Niggli, C.; Schmidt, H.-P.

2012-04-01

Viticulture is becoming the pioneering culture for biochar research. Biochar has been applied to many large-scale viticulture experiments across Europe this spring. After the first large-scale and long term experiments at the Delinat Institute in 2007-08, expectations are high. The latest results confirm these expectations and also show that only scientifically sound experiments will lead to conclusive information on the effect of biochar on vine growth and wine quality in many different climates and soil types. In the last three years it has been clearly shown that biologically activated biochar does not only have positive impact on soil-plant systems in the tropics, but in all soil types and climatic zones [Crane Droescher [2011], Ogawa [2010], IBI [2011]). While biochar improves water availability for plants and microorganisms in dry or seasonally dry farming areas, it also plays a substantial role in high rainfall zones because it improves nutrient dynamics through prevention of nutrient leaching. Spectacular crop growth can be seen in extreme climates (tropical or semi-desert), partly due to biochar's buffering capacity leading to the compensation of strong limiting factors (water in semi-deserts, washed-out nutrients in the tropics). In temperate climates, however, the achievable increase in harvest is lower as there are no extremely limiting elements which have to be compensated. In addition, potential maximum growth of many plant species is easily reached in temperate zones through using good fertilizers and careful seed selection. Therefore the advantage of biochar application in temperate climates is less evident as crop growth but rather is seen as plant quality improvement through optimizing plant nutrition. 1. Increase of plant resistance and hence reduction of plant protection products 2. Stimulation of soil microbial activity and symbioses between plants and soil organisms 3. Reduction in fertilizer use by optimizing the supply of nutrients, limiting nutrient losses 4. Improvement of taste and nutrient content of the crop 5. Improvement of shelf life 6. Reduction of greenhouse gas emissions and groundwater pollution Biochar is not a fertilizer, but rather a nutrient carrier and a habitat for microorganisms. If biochar is incorporated pure and without activation into the soil, its high adsorption capacity and increasing CEC will result in the absorption and fixing of available nutrients and water in the soil. This may lead to inhibition of plant growth, at least in the beginning (several months to a year), depending on the soil's nutrient content. Biochar needs to be charged to become biologically active in order to efficiently utilize its soil-enhancing properties. There are numerous methods of activating and producing substrates similar to terra preta aside from mixing biochar with compost. A new field experiment has been established in the vineyards of Delinat-Institute in 2011 to study the effects of biochar incorporation into compost preliminary to the composting process. Other field trials with manure-activated biochar were conducted this year by more than 15 companies in several major wine regions in Europe and first results have been evaluated.

Bioavailability of Dissolved Organic Carbon and Nitrogen From Tropical Montane Rainforest Streams Across a Geologic age Gradient

NASA Astrophysics Data System (ADS)

Wiegner, T. N.

2005-05-01

Dissolved organic matter (DOM) is metabolically important in streams. Its bioavailability is influenced by organic matter sources to streams and inorganic nutrient availability. As forest canopies and soils develop over time, organic matter inputs to streams should switch from algal to watershed sources. Across this succession gradient, nutrient limitation should also change. This study examines how chemical composition and bioavailability of DOM from tropical montane rainforest streams on Hawaii change across a geologic age gradient from 4 ky to 150 ky. Dissolved organic C (DOC) and N (DON) concentrations, chemical characteristics, and bioavailability varied with site age. With increasing stream age, DOC and DON concentrations, DOM aromaticity, and the C:N of the stream DOM increased. Changes in stream DOM chemistry and inorganic nutrient availability affected DOM bioavailability. Fifty percent of the DOC from the 4 ky site was bioavailable, where little to none was bioavailable from the older streams. Inorganic nutrient availability did not affect DOC bioavailability. In contrast, DON bioavailability was similar (12%) across sites and was affected by inorganic nutrient availability. This study demonstrates that the chemistry and metabolism of streams draining forests change with ecosystem age and development.

Competitive interactions between a nonmycorrhizal invasive plant, Alliaria petiolata, and a suite of mycorrhizal grassland, old field, and forest species.

PubMed

Poon, Gary T; Maherali, Hafiz

2015-01-01

The widespread invasion of the nonmycorrhizal biennial plant, Alliaria petiolata in North America is hypothesized to be facilitated by the production of novel biochemical weapons that suppress the growth of mycorrhizal fungi. As a result, A. petiolata is expected to be a strong competitor against plant species that rely on mycorrhizal fungi for nutrient uptake services. If A. petiolata is also a strong competitor for soil resources, it should deplete nutrients to levels lower than can be tolerated by weaker competitors. Because the negative effect of losing the fungal symbiont for mycorrhizal plants is greatest when nutrients are low, the ability of A. petiolata to simultaneously suppress fungi and efficiently take up soil nutrients should further strengthen its competitive ability against mycorrhizal plants. To test this hypothesis, we grew 27 mycorrhizal tree, forb and grass species that are representative of invaded habitats in the absence or presence of competition with A. petiolata in soils that had previously been experimentally planted with the invader or left as a control. A history of A. petiolata in soil reduced plant available forms of nitrogen by >50% and phosphorus by 17% relative to control soil. Average mycorrhizal colonization of competitor species was reduced by >50% in A. petiolata history versus control soil. Contrary to expectations, competition between A. petiolata and other species was stronger in control than history soil. The invader suppressed the biomass of 70% of competitor species in control soil but only 26% of species in history soil. In addition, A. petiolata biomass was reduced by 56% in history versus control soil, whereas the average biomass of competitor species was reduced by 15%. Thus, our results suggest that the negative effect of nutrient depletion on A. petiolata was stronger than the negative effect of suppressing mycorrhizal colonization on competitor species. These findings indicate that the inhibitory potential of A. petiolata on competitor species via mycorrhizal suppression is not enhanced under nutrient limitation.

Competitive interactions between a nonmycorrhizal invasive plant, Alliaria petiolata, and a suite of mycorrhizal grassland, old field, and forest species

PubMed Central

Poon, Gary T.

2015-01-01

The widespread invasion of the nonmycorrhizal biennial plant, Alliaria petiolata in North America is hypothesized to be facilitated by the production of novel biochemical weapons that suppress the growth of mycorrhizal fungi. As a result, A. petiolata is expected to be a strong competitor against plant species that rely on mycorrhizal fungi for nutrient uptake services. If A. petiolata is also a strong competitor for soil resources, it should deplete nutrients to levels lower than can be tolerated by weaker competitors. Because the negative effect of losing the fungal symbiont for mycorrhizal plants is greatest when nutrients are low, the ability of A. petiolata to simultaneously suppress fungi and efficiently take up soil nutrients should further strengthen its competitive ability against mycorrhizal plants. To test this hypothesis, we grew 27 mycorrhizal tree, forb and grass species that are representative of invaded habitats in the absence or presence of competition with A. petiolata in soils that had previously been experimentally planted with the invader or left as a control. A history of A. petiolata in soil reduced plant available forms of nitrogen by >50% and phosphorus by 17% relative to control soil. Average mycorrhizal colonization of competitor species was reduced by >50% in A. petiolata history versus control soil. Contrary to expectations, competition between A. petiolata and other species was stronger in control than history soil. The invader suppressed the biomass of 70% of competitor species in control soil but only 26% of species in history soil. In addition, A. petiolata biomass was reduced by 56% in history versus control soil, whereas the average biomass of competitor species was reduced by 15%. Thus, our results suggest that the negative effect of nutrient depletion on A. petiolata was stronger than the negative effect of suppressing mycorrhizal colonization on competitor species. These findings indicate that the inhibitory potential of A. petiolata on competitor species via mycorrhizal suppression is not enhanced under nutrient limitation. PMID:26213654

Ecological role of reindeer summer browsing in the mountain birch (Betula pubescens ssp. czerepanovii) forests: effects on plant defense, litter decomposition, and soil nutrient cycling.

PubMed

Stark, Sari; Julkunen-Tiitto, Riitta; Kumpula, Jouko

2007-03-01

Mammalian herbivores commonly alter the concentrations of secondary compounds in plants and, by this mechanism, have indirect effects on litter decomposition and soil carbon and nutrient cycling. In northernmost Fennoscandia, the subarctic mountain birch (Betula pubescens ssp. czerepanovii) forests are important pasture for the semidomestic reindeer (Rangifer tarandus). In the summer ranges, mountain birches are intensively browsed, whereas in the winter ranges, reindeer feed on ground lichens, and the mountain birches remain intact. We analyzed the effect of summer browsing on the concentrations of secondary substances, litter decomposition, and soil nutrient pools in areas that had been separated as summer or winter ranges for at least 20 years, and we predicted that summer browsing may reduce levels of secondary compounds in the mountain birch and, by this mechanism, have an indirect effect on the decomposition of mountain birch leaf litter and soil nutrient cycling. The effect of browsing on the concentration of secondary substances in the mountain birch leaves varied between different years and management districts, but in some cases, the concentration of condensed tannins was lower in the summer than in the winter ranges. In a reciprocal litter decomposition trial, both litter origin and emplacement significantly affected the litter decomposition rate. Decomposition rates were faster for the litter originating from and placed into the summer range. Soil inorganic nitrogen (N) concentrations were higher in the summer than in the winter ranges, which indicates that reindeer summer browsing may enhance the soil nutrient cycling. There was a tight inverse relationship between soil N and foliar tannin concentrations in the winter range but not in the summer range. This suggests that in these strongly nutrient-limited ecosystems, soil N availability regulates the patterns of resource allocation to condensed tannins in the absence but not in the presence of browsing.

Forage nutritive quality in the Serengeti ecosystem: The roles of fire and herbivory

USGS Publications Warehouse

Anderson, T.M.; Ritchie, M.E.; Mayemba, E.; Eby, S.; Grace, J.B.; McNaughton, S.J.

2007-01-01

Fire and herbivory are important determinants of nutrient availability in savanna ecosystems. Fire and herbivory effects on the nutritive quality of savanna vegetation can occur directly, independent of changes in the plant community, or indirectly, via effects on the plant community. Indirect effects can be further subdivided into those occurring because of changes in plant species composition or plant abundance (i.e., quality versus quantity). We studied relationships between fire, herbivory, rainfall, soil fertility, and leaf nitrogen (N), phosphorus (P), and sodium (Na) at 30 sites inside and outside of Serengeti National Park. Using structural equation modeling, we asked whether fire and herbivory influences were largely direct or indirect and how their signs and strengths differed within the context of natural savanna processes. Herbivory was associated with enhanced leaf N and P through changes in plant biomass and community composition. Fire was associated with reduced leaf nutrient concentrations through changes in plant community composition. Additionally, fire had direct positive effects on Na and nonlinear direct effects on P that partially mitigated the indirect negative effects. Key mechanisms by which fire reduced plant nutritive quality were through reductions of Na-rich grasses and increased abundance of Themeda triandra, which had below-average leaf nutrients. ?? 2007 by The University of Chicago. All rights reserved.

Site-specific nutrient management systems

USDA-ARS?s Scientific Manuscript database

Site-specific nutrient management systems were created to manage for spatial and temporal variability in biophysical factors that determine the availability and demand of crop nutrients. These systems differ among geographical regions in the information utilized and way they operate to accomplish th...

Non Pharmacological Cognitive Enhancers – Current Perspectives

PubMed Central

Kumar, Kuldip; Anand, Kuljeet Singh

2015-01-01

Cognition refers to the mental processes involved in thinking, knowing, remembering, judging, and problem solving. Cognitive dysfunctions are an integral part of neuropsychiatric disorders as well as in healthy ageing. Cognitive Enhancers are molecules that help improve aspects of cognition like memory, intelligence, motivation, attention and concentration. Recently, Non Pharmacological Cognitive Enhancers have gained popularity as effective and safe alternative to various established drugs. Many of these Non Pharmacological Cognitive Enhancers seem to be more efficacious compared to currently available Pharmacological Cognitive Enhancers. This review describes and summarizes evidence on various Non Pharmacological Cognitive Enhancers such as physical exercise, sleep, meditation and yoga, spirituality, nutrients, computer training, brain stimulation, and music. We also discuss their role in ageing and different neuro-psychiatric disorders, and current status of Cochrane database recommendations. We searched the Pubmed database for the articles and reviews having the terms ‘non pharmacological and cognitive’ in the title, published from 2000 till 2014. A total of 11 results displayed, out of which 10 were relevant to the review. These were selected and reviewed. Appropriate cross-references within the articles along with Cochrane reviews were also considered and studied. PMID:26393186

Spatial Heterogeneity of Soil Nutrients after the Establishment of Caragana intermedia Plantation on Sand Dunes in Alpine Sandy Land of the Tibet Plateau

PubMed Central

Li, Qingxue; Jia, Zhiqing; Zhu, Yajuan; Wang, Yongsheng; Li, Hong; Yang, Defu; Zhao, Xuebin

2015-01-01

The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil “fertile islands” were formed, and the “fertile islands” were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous shrub. PMID:25946170

Spatial Heterogeneity of Soil Nutrients after the Establishment of Caragana intermedia Plantation on Sand Dunes in Alpine Sandy Land of the Tibet Plateau.

PubMed

Li, Qingxue; Jia, Zhiqing; Zhu, Yajuan; Wang, Yongsheng; Li, Hong; Yang, Defu; Zhao, Xuebin

2015-01-01

The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil "fertile islands" were formed, and the "fertile islands" were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous shrub.

Significance of Plankton Community Structure and Nutrient Availability for the Control of Dinoflagellate Blooms by Parasites: A Modeling Approach

PubMed Central

Alves-de-Souza, Catharina; Pecqueur, David; Le Floc’h, Emilie; Mas, Sébastien; Roques, Cécile; Mostajir, Behzad; Vidussi, Franscesca; Velo-Suárez, Lourdes; Sourisseau, Marc; Fouilland, Eric; Guillou, Laure

2015-01-01

Dinoflagellate blooms are frequently observed under temporary eutrophication of coastal waters after heavy rains. Growth of these opportunistic microalgae is believed to be promoted by sudden input of nutrients and the absence or inefficiency of their natural enemies, such as grazers and parasites. Here, numerical simulations indicate that increasing nutrient availability not only promotes the formation of dinoflagellate blooms but can also stimulate their control by protozoan parasites. Moreover, high abundance of phytoplankton other than dinoflagellate hosts might have a significant dilution effect on the control of dinoflagellate blooms by parasites, either by resource competition with dinoflagellates (thus limiting the number of hosts available for infection) or by affecting numerical-functional responses of grazers that consume free-living parasite stages. These outcomes indicate that although both dinoflagellates and their protozoan parasites are directly affected by nutrient availability, the efficacy of the parasitic control of dinoflagellate blooms under temporary eutrophication depends strongly on the structure of the plankton community as a whole. PMID:26030411

Interactive effects of phosphorus deficiency and exogenous auxin on root morphological and physiological traits in white lupin (Lupinus albus L.).

PubMed

Tang, Hongliang; Shen, Jianbo; Zhang, Fusuo; Rengel, Zed

2013-04-01

White lupin (Lupinus albus) exhibits strong root morphological and physiological responses to phosphorus (P) deficiency and auxin treatments, but the interactive effects of P and auxin in regulating root morphological and physiological traits are not fully understood. This study aimed to assess white lupin root traits as influenced by P (0 or 250 μmol L(-1)) and auxin (10(-8) mol L(-1) NAA) in nutrient solution. Both P deficiency and auxin treatments significantly altered root morphological traits, as evidenced by reduced taproot length, increased number and density of first-order lateral roots, and enhanced cluster-root formation. Changes in root physiological traits were also observed, i.e., increased proton, citrate, and acid phosphatase exudation. Exogenous auxin enhanced root responses and sensitivity to P deficiency. A significant interplay exists between P and auxin in the regulation of root morphological and physiological traits. Principal component analysis showed that P availability explained 64.8% and auxin addition 21.3% of the total variation in root trait parameters, indicating that P availability is much more important than auxin in modifying root responses of white lupin. This suggests that white lupin can coordinate root morphological and physiological responses to enhance acquisition of P resources, with an optimal trade-off between root morphological and physiological traits regulated by external stimuli such as P availability and auxin.

Fall fertilization of Pinus resinosa seedlings: nutrient uptake, cold hardiness, and morphological development

Treesearch

M. Anisul Islam; Kent G. Apostol; Douglass F. Jacobs; R. Kasten Dumroese

2009-01-01

Fertilization is an integral component of nursery culture for production of high quality seedlings for afforestation and reforestation because it can enhance plant growth, nutrient storage reserves, and resistance to biotic and abiotic stresses (Landis, 1985). While fertilizer is conventionally applied during spring and summer in accordance with the...

Illustrated manual on composting for improved soil fertility and enhanced cocoa production

USDA-ARS?s Scientific Manuscript database

In West and Central Africa, most cocoa farms are old and the soils are highly depleted in major nutrients. Cocoa pod harvest continues to remove nutrients, and this loss of soil fertility is one of the major causes of low cocoa yields and subsequent economic losses. Plant pathogens, including nema...

Carbon Stable Isotope Values in Plankton and Mussels Reflect Changes in Carbonate Chemistry Associated with Nutrient Enhanced Net Production

EPA Science Inventory

Coastal ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13C) measurements could play in understanding that adaptation with a series of three Ecostat (i.e...

Framework to parameterize and validate APEX to support deployment of the nutrient tracking tool

USDA-ARS?s Scientific Manuscript database

The Agricultural Policy Environmental eXtender (APEX) model is the scientific basis for the Nutrient Tracking Tool (NTT). NTT is an enhanced version of the Nitrogen Trading Tool, a user-friendly web-based computer program originally developed by the USDA. NTT was developed to estimate reductions in...

Nutrient concentrations and fluxes in tributaries to the Swan-Canning estuary, Western Australia

USGS Publications Warehouse

Peters, N.E.; Donohue, R.

1999-01-01

In Western Australia, catchment nutrient availability on an areal basis is primarily controlled by the disposal of animal waste and the type and rate of fertilizer application, particularly in coastal areas. The coastal areas receive notably higher rainfall and have more intense horticulture and animal production than inland areas, and are undergoing rapid urbanization, particularly adjacent to the estuary. Also, the surficial aquifers on the coastal plain are generally sandy having a low nutrient retention capacity and rapidly transmit soluble and colloidal material through the subsurface. In the Swan-Canning basin, high air and soil temperatures and seasonally arid conditions cause rapid mineralization of nitrogen and phosphorus. The nutrients are subsequently available for transport during the onset of seasonal wet weather, which typically begins during the period from late April to June. In addition to the rapid mobility of nutrients in streamwater from agricultural areas during the wet season, drains in urban areas, which typically have high nutrient concentrations, also are an important source of nutrients as the drains flow directly to the estuary throughout the year.

Community temporal variability increases with fluctuating resource availability

PubMed Central

Li, Wei; Stevens, M. Henry H.

2017-01-01

An increase in the quantity of available resources is known to affect temporal variability of aggregate community properties. However, it is unclear how might fluctuations in resource availability alter community-level temporal variability. Here we conduct a microcosm experiment with laboratory protist community subjected to manipulated resource pulses that vary in intensity, duration and time of supply, and examine the impact of fluctuating resource availability on temporal variability of the recipient community. The results showed that the temporal variation of total protist abundance increased with the magnitude of resource pulses, as protist community receiving infrequent resource pulses (i.e., high-magnitude nutrients per pulse) was relatively more unstable than community receiving multiple resource pulses (i.e., low-magnitude nutrients per pulse), although the same total amounts of nutrients were added to each community. Meanwhile, the timing effect of fluctuating resources did not significantly alter community temporal variability. Further analysis showed that fluctuating resource availability increased community temporal variability by increasing the degree of community-wide species synchrony and decreasing the stabilizing effects of dominant species. Hence, the importance of fluctuating resource availability in influencing community stability and the regulatory mechanisms merit more attention, especially when global ecosystems are experiencing high rates of anthropogenic nutrient inputs. PMID:28345592

Community temporal variability increases with fluctuating resource availability

NASA Astrophysics Data System (ADS)

Li, Wei; Stevens, M. Henry H.

2017-03-01

An increase in the quantity of available resources is known to affect temporal variability of aggregate community properties. However, it is unclear how might fluctuations in resource availability alter community-level temporal variability. Here we conduct a microcosm experiment with laboratory protist community subjected to manipulated resource pulses that vary in intensity, duration and time of supply, and examine the impact of fluctuating resource availability on temporal variability of the recipient community. The results showed that the temporal variation of total protist abundance increased with the magnitude of resource pulses, as protist community receiving infrequent resource pulses (i.e., high-magnitude nutrients per pulse) was relatively more unstable than community receiving multiple resource pulses (i.e., low-magnitude nutrients per pulse), although the same total amounts of nutrients were added to each community. Meanwhile, the timing effect of fluctuating resources did not significantly alter community temporal variability. Further analysis showed that fluctuating resource availability increased community temporal variability by increasing the degree of community-wide species synchrony and decreasing the stabilizing effects of dominant species. Hence, the importance of fluctuating resource availability in influencing community stability and the regulatory mechanisms merit more attention, especially when global ecosystems are experiencing high rates of anthropogenic nutrient inputs.

Nanotechnology in Sustainable Agriculture: Recent Developments, Challenges, and Perspectives

PubMed Central

Prasad, Ram; Bhattacharyya, Atanu; Nguyen, Quang D.

2017-01-01

Nanotechnology monitors a leading agricultural controlling process, especially by its miniature dimension. Additionally, many potential benefits such as enhancement of food quality and safety, reduction of agricultural inputs, enrichment of absorbing nanoscale nutrients from the soil, etc. allow the application of nanotechnology to be resonant encumbrance. Agriculture, food, and natural resources are a part of those challenges like sustainability, susceptibility, human health, and healthy life. The ambition of nanomaterials in agriculture is to reduce the amount of spread chemicals, minimize nutrient losses in fertilization and increased yield through pest and nutrient management. Nanotechnology has the prospective to improve the agriculture and food industry with novel nanotools for the controlling of rapid disease diagnostic, enhancing the capacity of plants to absorb nutrients among others. The significant interests of using nanotechnology in agriculture includes specific applications like nanofertilizers and nanopesticides to trail products and nutrients levels to increase the productivity without decontamination of soils, waters, and protection against several insect pest and microbial diseases. Nanotechnology may act as sensors for monitoring soil quality of agricultural field and thus it maintain the health of agricultural plants. This review covers the current challenges of sustainability, food security and climate change that are exploring by the researchers in the area of nanotechnology in the improvement of agriculture. PMID:28676790

Nanotechnology in Sustainable Agriculture: Recent Developments, Challenges, and Perspectives.

PubMed

Prasad, Ram; Bhattacharyya, Atanu; Nguyen, Quang D

2017-01-01

Nanotechnology monitors a leading agricultural controlling process, especially by its miniature dimension. Additionally, many potential benefits such as enhancement of food quality and safety, reduction of agricultural inputs, enrichment of absorbing nanoscale nutrients from the soil, etc. allow the application of nanotechnology to be resonant encumbrance. Agriculture, food, and natural resources are a part of those challenges like sustainability, susceptibility, human health, and healthy life. The ambition of nanomaterials in agriculture is to reduce the amount of spread chemicals, minimize nutrient losses in fertilization and increased yield through pest and nutrient management. Nanotechnology has the prospective to improve the agriculture and food industry with novel nanotools for the controlling of rapid disease diagnostic, enhancing the capacity of plants to absorb nutrients among others. The significant interests of using nanotechnology in agriculture includes specific applications like nanofertilizers and nanopesticides to trail products and nutrients levels to increase the productivity without decontamination of soils, waters, and protection against several insect pest and microbial diseases. Nanotechnology may act as sensors for monitoring soil quality of agricultural field and thus it maintain the health of agricultural plants. This review covers the current challenges of sustainability, food security and climate change that are exploring by the researchers in the area of nanotechnology in the improvement of agriculture.

Future changes in coastal upwelling ecosystems with global warming: The case of the California Current System.

PubMed

Xiu, Peng; Chai, Fei; Curchitser, Enrique N; Castruccio, Frederic S

2018-02-12

Coastal upwelling ecosystems are among the most productive ecosystems in the world, meaning that their response to climate change is of critical importance. Our understanding of climate change impacts on marine ecosystems is largely limited to the open ocean, mainly because coastal upwelling is poorly reproduced by current earth system models. Here, a high-resolution model is used to examine the response of nutrients and plankton dynamics to future climate change in the California Current System (CCS). The results show increased upwelling intensity associated with stronger alongshore winds in the coastal region, and enhanced upper-ocean stratification in both the CCS and open ocean. Warming of the open ocean forces isotherms downwards, where they make contact with water masses with higher nutrient concentrations, thereby enhancing the nutrient flux to the deep source waters of the CCS. Increased winds and eddy activity further facilitate upward nutrient transport to the euphotic zone. However, the plankton community exhibits a complex and nonlinear response to increased nutrient input, as the food web dynamics tend to interact differently. This analysis highlights the difficulty in understanding how the marine ecosystem responds to a future warming climate, given to range of relevant processes operating at different scales.

An ecological vegetation-activated sludge process (V-ASP) for decentralized wastewater treatment: system development, treatment performance, and mathematical modeling.

PubMed

Yuan, Jiajia; Dong, Wenyi; Sun, Feiyun; Li, Pu; Zhao, Ke

2016-05-01

An environment-friendly decentralized wastewater treatment process that is comprised of activated sludge process (ASP) and wetland vegetation, named as vegetation-activated sludge process (V-ASP), was developed for decentralized wastewater treatment. The long-term experimental results evidenced that the vegetation sequencing batch reactor (V-SBR) process had consistently stable higher removal efficiencies of organic substances and nutrients from domestic wastewater compared with traditional sequencing batch reactor (SBR). The vegetation allocated into V-SBR system could not only remove nutrients through its vegetation transpiration ratio but also provide great surface area for microorganism activity enhancement. This high vegetation transpiration ratio enhanced nutrients removal effectiveness from wastewater mainly by flux enhancement, oxygen and substrate transportation acceleration, and vegetation respiration stimulation. A mathematical model based on ASM2d was successfully established by involving the specific function of vegetation to simulate system performance. The simulation results on the influence of operational parameters on V-ASP treatment effectiveness demonstrated that V-SBR had a high resistance to seasonal temperature fluctuations and influent loading shocking.

ENSO-driven nutrient variability recorded by central equatorial Pacific corals

NASA Astrophysics Data System (ADS)

LaVigne, M.; Nurhati, I. S.; Cobb, K. M.; McGregor, H. V.; Sinclair, D. J.; Sherrell, R. M.

2012-12-01

Recent evidence for shifts in global ocean primary productivity suggests that surface ocean nutrient availability is a key link between global climate and ocean carbon cycling. Time-series records from satellite, in situ buoy sensors, and bottle sampling have documented the impact of the El Niño Southern Oscillation (ENSO) on equatorial Pacific hydrography and broad changes in biogeochemistry since the late 1990's, however, data are sparse prior to this. Here we use a new paleoceanographic nutrient proxy, coral P/Ca, to explore the impact of ENSO on nutrient availability in the central equatorial Pacific at higher-resolution than available from in situ nutrient data. Corals from Christmas (157°W 2°N) and Fanning (159°W 4°N) Islands recorded a well-documented decrease in equatorial upwelling as a ~40% decrease in P/Ca during the 1997-98 ENSO cycle, validating the application of this proxy to Pacific Porites corals. We compare the biogeochemical shifts observed through the 1997-98 event with two pre-TOGA-TAO ENSO cycles (1982-83 and 1986-87) reconstructed from a longer Christmas Island core. All three corals revealed ~30-40% P/Ca depletions during ENSO warming as a result of decreased regional wind stress, thermocline depth, and equatorial upwelling velocity. However, at the termination of each El Niño event, surface nutrients did not return to pre-ENSO levels for ~4-12 months after, SST as a result of increased biological draw down of surface nutrients. These records demonstrate the utility of high-resolution coral nutrient archives for understanding the impact of tropical Pacific climate on the nutrient and carbon cycling of this key region.

Engineering crop nutrient efficiency for sustainable agriculture.

PubMed

Chen, Liyu; Liao, Hong

2017-10-01

Increasing crop yields can provide food, animal feed, bioenergy feedstocks and biomaterials to meet increasing global demand; however, the methods used to increase yield can negatively affect sustainability. For example, application of excess fertilizer can generate and maintain high yields but also increases input costs and contributes to environmental damage through eutrophication, soil acidification and air pollution. Improving crop nutrient efficiency can improve agricultural sustainability by increasing yield while decreasing input costs and harmful environmental effects. Here, we review the mechanisms of nutrient efficiency (primarily for nitrogen, phosphorus, potassium and iron) and breeding strategies for improving this trait, along with the role of regulation of gene expression in enhancing crop nutrient efficiency to increase yields. We focus on the importance of root system architecture to improve nutrient acquisition efficiency, as well as the contributions of mineral translocation, remobilization and metabolic efficiency to nutrient utilization efficiency. © 2017 Institute of Botany, Chinese Academy of Sciences.

Soil moisture and biogeochemical factors influence the distribution of annual Bromus species

USGS Publications Warehouse

Belnap, Jayne; Stark, John Thomas; Rau, Benjamin; Allen, Edith B.; Phillips, Sue

2016-01-01

Abiotic factors have a strong influence on where annual Bromus species are found. At the large regional scale, temperature and precipitation extremes determine the boundaries of Bromusoccurrence. At the more local scale, soil characteristics and climate influence distribution, cover, and performance. In hot, dry, summer-rainfall-dominated deserts (Sonoran, Chihuahuan), little or noBromus is found, likely due to timing or amount of soil moisture relative to Bromus phenology. In hot, winter-rainfall-dominated deserts (parts of the Mojave Desert), Bromus rubens is widespread and correlated with high phosphorus availability. It also responds positively to additions of nitrogen alone or with phosphorus. On the Colorado Plateau, with higher soil moisture availability, factors limiting Bromus tectorum populations vary with life stage: phosphorus and water limit germination, potassium and the potassium/magnesium ratio affect winter performance, and water and potassium/magnesium affect spring performance. Controlling nutrients also change with elevation. In cooler deserts with winter precipitation (Great Basin, Columbia Plateau) and thus even greater soil moisture availability, B. tectorum populations are controlled by nitrogen, phosphorus, or potassium. Experimental nitrogen additions stimulate Bromus performance. The reason for different nutrients limiting in dissimilar climatic regions is not known, but it is likely that site conditions such as soil texture (as it affects water and nutrient availability), organic matter, and/or chemistry interact in a manner that regulates nutrient availability and limitations. Under future drier, hotter conditions,Bromus distribution is likely to change due to changes in the interaction between moisture and nutrient availability.

Organic coating on biochar explains its nutrient retention and stimulation of soil fertility.

PubMed

Hagemann, Nikolas; Joseph, Stephen; Schmidt, Hans-Peter; Kammann, Claudia I; Harter, Johannes; Borch, Thomas; Young, Robert B; Varga, Krisztina; Taherymoosavi, Sarasadat; Elliott, K Wade; McKenna, Amy; Albu, Mihaela; Mayrhofer, Claudia; Obst, Martin; Conte, Pellegrino; Dieguez-Alonso, Alba; Orsetti, Silvia; Subdiaga, Edisson; Behrens, Sebastian; Kappler, Andreas

2017-10-20

Amending soil with biochar (pyrolized biomass) is suggested as a globally applicable approach to address climate change and soil degradation by carbon sequestration, reducing soil-borne greenhouse-gas emissions and increasing soil nutrient retention. Biochar was shown to promote plant growth, especially when combined with nutrient-rich organic matter, e.g., co-composted biochar. Plant growth promotion was explained by slow release of nutrients, although a mechanistic understanding of nutrient storage in biochar is missing. Here we identify a complex, nutrient-rich organic coating on co-composted biochar that covers the outer and inner (pore) surfaces of biochar particles using high-resolution spectro(micro)scopy and mass spectrometry. Fast field cycling nuclear magnetic resonance, electrochemical analysis and gas adsorption demonstrated that this coating adds hydrophilicity, redox-active moieties, and additional mesoporosity, which strengthens biochar-water interactions and thus enhances nutrient retention. This implies that the functioning of biochar in soil is determined by the formation of an organic coating, rather than biochar surface oxidation, as previously suggested.

[Relationships between soil nutrients and rhizospheric soil microbial communities and enzyme activities in a maize-capsicum intercropping system].

PubMed

Xu, Qiang; Cheng, Zhi-Hui; Meng, Huan-Wen; Zhang, Yu

2007-12-01

By using plastic sheet and nylon mesh to partition the root systems of maize and capsicum in a maize-capsicum intercropping system, this paper studied the relationships between soil biological factors and nutritive status in the intercropping system, with no partitioning and maize monoculture and capsicum monoculture as the control. The results showed that intercropping maize and capsicum had its high superiority. In the treatments of no partitioning and nylon mesh portioning in the intercropping system, soil enzyme activities, microbial individuals and nutrient contents were significantly higher, compared with those in the treatments of nylon mesh partitioning and monocultures. All kinds of soil available nutrients showed significant or very significant positive correlations with soil biological factors, except that soil available Mg was negatively correlated with soil fungi and catalase activity. Pathway analysis indicated that in the intercropping system, soil urease, catalase, protease, and bacteria were the main factors affecting the accumulation of soil organic matter, saccharase was the most important factor affecting soil alkali-hydrolyzable N, urease was the most important factor affecting soil available P, and bacteria largely determined soil available K. Soil alkaline phosphatase and fungi selectively affected the accumulation of soil organic matter and available N, P and K. There was a slight negative correlation between soil actinomycetes and soil nutrients, suggesting that actinomycetes had little effect on soil nutrient formation.

Neuronal regulation of homeostasis by nutrient sensing.

PubMed

Lam, Tony K T

2010-04-01

In type 2 diabetes and obesity, the homeostatic control of glucose and energy balance is impaired, leading to hyperglycemia and hyperphagia. Recent studies indicate that nutrient-sensing mechanisms in the body activate negative-feedback systems to regulate energy and glucose homeostasis through a neuronal network. Direct metabolic signaling within the intestine activates gut-brain and gut-brain-liver axes to regulate energy and glucose homeostasis, respectively. In parallel, direct metabolism of nutrients within the hypothalamus regulates food intake and blood glucose levels. These findings highlight the importance of the central nervous system in mediating the ability of nutrient sensing to maintain homeostasis. Futhermore, they provide a physiological and neuronal framework by which enhancing or restoring nutrient sensing in the intestine and the brain could normalize energy and glucose homeostasis in diabetes and obesity.

Isolation and characterization of N2 -fixing bacteria from giant reed and switchgrass for plant growth promotion and nutrient uptake.

PubMed

Xu, Jia; Kloepper, Joseph W; Huang, Ping; McInroy, John A; Hu, Chia H

2018-05-01

The aims of this study were to isolate and characterize N 2 -fixing bacteria from giant reed and switchgrass and evaluate their plant growth promotion and nutrient uptake potential for use as biofertilizers. A total of 190 bacteria were obtained from rhizosphere soil and inside stems and roots of giant reed and switchgrass. All the isolates were confirmed to have nitrogenase activity, 96.9% produced auxin, and 85% produced siderophores. Then the top six strains, including Sphingomonas trueperi NNA-14, Sphingomonas trueperi NNA-19, Sphingomonas trueperi NNA-17, Sphingomonas trueperi NNA-20, Psychrobacillus psychrodurans NP-3, and Enterobacter oryzae NXU-38, based on nitrogenase activity, were inoculated on maize and wheat seeds in greenhouse tests to assess their potential benefits to plants. All the selected strains promoted plant growth by increasing at least one plant growth parameter or increasing the nutrient concentration of maize or wheat plants. NNA-14 outperformed others in promoting early growth and nutrient uptake by maize. Specifically, NNA-14 significantly increased root length, surface area, and fine roots of maize by 14%, 12%, and 17%, respectively, and enhanced N, Ca, S, B, Cu, and Zn in maize. NNA-19 and NXU-38 outperformed others in promoting both early growth and nutrient uptake by wheat. Specifically, NNA-19 significantly increased root dry weight and number of root tips of wheat by 25% and 96%, respectively, and enhanced Ca in wheat. NXU-38 significantly increased root length, surface area, and fine roots of wheat by 21%, 13%, and 26%, respectively, and enhanced levels of Ca and Mg in wheat. It is concluded that switchgrass and giant reed are colonized by N 2 -fixing bacteria that have the potential to contribute to plant growth and nutrient uptake by agricultural crops. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Native Mussels Alter Nutrient Availability and Reduce Blue-Green Algae Abundance

EPA Science Inventory

Nutrient cycling is a key process that ties all organisms together. This is especially apparent in stream environments in which nutrients are taken up readily and cycled through the system in a downstream trajectory. Ecological stoichiometry predicts that biogeochemical cycles of...

NUTRIENT TRANSPORT DURING BIOREMEDIATION OF CONTAMINATED BEACHES: EVALUATION WITH LITHIUM AS A CONSERVATIVE TRACER

EPA Science Inventory

Bioremediation of oil-contaminated beaches typically involves fertilization with nutrients that are thought to limit the growth rate of hydrocarbon-degrading bacteria. Much of the available technology involves application of fertilizers that release nutrients in a water-soluble ...

Sewage input reduces the consumption of Rhizophora mangle propagules by crabs in a subtropical mangrove system.

PubMed

Boehm, Frederike Ricarda; Sandrini-Neto, Leonardo; Moens, Tom; da Cunha Lana, Paulo

2016-12-01

Mangrove forests are highly productive and play a major role in global carbon cycling. Their carbon accumulation can be influenced through the consumption of nutrient-poor leaves and propagules by herbivore crabs. Anthropogenic nutrient input from sewage contamination is widespread in these often naturally nutrient-limited ecosystems. We hypothesised that sewage-mediated nutrient input to mangrove stands of Paranaguá Bay (southern Brazil), would alter the nutrient sources available for crabs, e.g. through microphytobenthos increase, and that this would reflect in their feeding behaviour. We predicted that propagules of Rhizophora mangle in contaminated stands would experience lower grazing pressure from their two main local consumers (Ucides cordatus and Goniopsis cruentata). We compared herbivory rates on R. mangle propagules in sewage contaminated and uncontaminated mangrove stands. We found that herbivory rates were significantly lower in contaminated than uncontaminated forests, but this pattern could not be clearly attributed to increased nutrient availability. Copyright © 2016 Elsevier Ltd. All rights reserved.

PPARγ-mediated increase in glucose availability sustains chronic Brucella abortus infection in alternatively activated macrophages

PubMed Central

Xavier, Mariana N.; Winter, Maria G.; Spees, Alanna M.; den Hartigh, Andreas B.; Nguyen, Kim; Roux, Christelle M.; Silva, Teane M. A.; Atluri, Vidya L.; Kerrinnes, Tobias; Keestra, A. Marijke; Monack, Denise M.; Luciw, Paul A.; Eigenheer, Richard A.; Bäumler, Andreas J.; Santos, Renato L.; Tsolis, Renée M.

2013-01-01

SUMMARY Eradication of persistent intracellular bacterial pathogens with antibiotic therapy is often slow or incomplete. However, strategies to augment antibiotics are hampered by our poor understanding of the nutritional environment that sustains chronic infection. Here we show that the intracellular pathogen Brucella abortus survives and replicates preferentially in alternatively activated macrophages (AAM), which are more abundant during chronic infection. A metabolic shift induced by peroxisome proliferator activated receptor γ (PPARγ), which increases intracellular glucose availability, is identified as a causal mechanism promoting enhanced bacterial survival in AAM. Glucose uptake was crucial for increased replication of B. abortus in AAM, and chronic infection, as inactivation of the bacterial glucose transporter gluP reduced both intracellular survival in AAM and persistence in mice. Thus, a shift in intracellular nutrient availability induced by PPARγ promotes chronic persistence of B. abortus within AAM and targeting this pathway may aid in eradicating chronic infection. PMID:23954155

Part 1: Vadose-zone column studies of toluene (enhanced bioremediation) in a shallow unconfined aquifer

USGS Publications Warehouse

Tindall, J.A.; Friedel, M.J.; Szmajter, R.J.; Cuffin, S.M.

2005-01-01

The objectives of the laboratory study described in this paper were (1) to determine the effectiveness of four nutrient solutions and a control in stimulating the microbial degradation of toluene in the unsaturated zone as an alternative to bioremediation methodologies such as air sparging, in situ vitrification, or others (Part I), and (2) to compare the effectiveness of the addition of the most effective nutrient solution from Part I (modified Hoagland type, nitrate-rich) and hydrogen peroxide (H2O2) on microbial degradation of toluene for repeated, simulated spills in the unsaturated zone (Part II). For Part 1, fifteen columns (30-cm diameter by 150-cm height), packed with air-dried, 0.25-mm, medium-fine sand, were prepared to simulate shallow unconfined aquifer conditions. Toluene (10 mL) was added to the surface of each column, and soil solution and soil gas samples were collected from the columns every third day for 21 days. On day 21, a second application of toluene (10 mL) was made, and the experiment was run for another 21 days. Solution 4 was the most effective for microbial degradation in Part I. For Part II, three columns were designated nutrient-rich 3-day toluene columns and received toluene injections every 3 days; three columns were designated as nutrient-rich 7-day columns and received toluene injections every 7 days; and two columns were used as controls to which no nutrient was added. As measured by CO2 respiration, the initial benefits for aerobic organisms from the O2 enhancement were sustained by the bacteria for only a short period of time (about 8 days). Degradation benefits from the nutrient solution were sustained throughout the experiment. The O2 and nutrient-enhanced columns degraded significantly more toluene than the control columns when simulating repeated spills onto the unsaturated zone, and demonstrated a potentially effective in situ bioremediation technology when used immediately or within days after a spill. The combined usage of H 2O2 and nitrate-rich nutrients served to effectively maximize natural aerobic and anaerobic metabolic processes that biodegrade hydrocarbons in petroleum-contaminated media. Applications of this technology in the field may offer economical advantages to other, more intrusive abatement technologies. ?? Springer 2005.

Phytosterols Play a Key Role in Plant Innate Immunity against Bacterial Pathogens by Regulating Nutrient Efflux into the Apoplast1[C][W][OA

PubMed Central

Wang, Keri; Senthil-Kumar, Muthappa; Ryu, Choong-Min; Kang, Li; Mysore, Kirankumar S.

2012-01-01

Bacterial pathogens colonize a host plant by growing between the cells by utilizing the nutrients present in apoplastic space. While successful pathogens manipulate the plant cell membrane to retrieve more nutrients from the cell, the counteracting plant defense mechanism against nonhost pathogens to restrict the nutrient efflux into the apoplast is not clear. To identify the genes involved in nonhost resistance against bacterial pathogens, we developed a virus-induced gene-silencing-based fast-forward genetics screen in Nicotiana benthamiana. Silencing of N. benthamiana SQUALENE SYNTHASE, a key gene in phytosterol biosynthesis, not only compromised nonhost resistance to few pathovars of Pseudomonas syringae and Xanthomonas campestris, but also enhanced the growth of the host pathogen P. syringae pv tabaci by increasing nutrient efflux into the apoplast. An Arabidopsis (Arabidopsis thaliana) sterol methyltransferase mutant (sterol methyltransferase2) involved in sterol biosynthesis also compromised plant innate immunity against bacterial pathogens. The Arabidopsis cytochrome P450 CYP710A1, which encodes C22-sterol desaturase that converts β-sitosterol to stigmasterol, was dramatically induced upon inoculation with nonhost pathogens. An Arabidopsis Atcyp710A1 null mutant compromised both nonhost and basal resistance while overexpressors of AtCYP710A1 enhanced resistance to host pathogens. Our data implicate the involvement of sterols in plant innate immunity against bacterial infections by regulating nutrient efflux into the apoplast. PMID:22298683

Effect of exogenous abscisic acid on morphology, growth and nutrient uptake of rice (Oryza sativa) roots under simulated acid rain stress.

PubMed

Liu, Hongyue; Ren, Xiaoqian; Zhu, Jiuzheng; Wu, Xi; Liang, Chanjuan

2018-05-31

Application of proper ABA can improve acid tolerance of rice roots by balancing endogenous hormones and promoting nutrient uptake. Abscisic acid (ABA) has an important signaling role in enhancing plant tolerance to environmental stress. To alleviate the inhibition on plant growth and productivity caused by acid rain, it is crucial to clarify the regulating mechanism of ABA on adaptation of plants to acid rain. Here, we studied the effects of exogenously applied ABA on nutrients uptake of rice roots under simulated acid rain (SAR) stress from physiological, biochemical and molecular aspects. Compared to the single SAR treatment (pH 4.5 or 3.5), exogenous 10 μM ABA alleviated the SAR-induced inhibition of root growth by balancing endogenous hormones (abscisic acid, indole-3-acetic acid, gibberellic acid and zeatin), promoting nutrient uptake (nitrate, P, K and Mg) in rice roots, and increasing the activity of the plasma membrane H + -ATPase by up-regulating expression levels of genes (OSA2, OSA4, OSA9 and OSA10). However, exogenous 100 μM ABA exacerbated the SAR-caused inhibition of root growth by disrupting the balance of endogenous hormones, and inhibiting nutrient uptake (nitrate, P, K, Ca and Mg) through decreasing the activity of the plasma membrane H + -ATPase. These results indicate that proper concentration of exogenous ABA could enhance tolerance of rice roots to SAR stress by promoting nutrients uptake and balancing endogenous hormones.

Experimental study of clay-hydrocarbon interactions relevant to the biodegradation of the Deepwater Horizon oil from the Gulf of Mexico.

PubMed

Warr, Laurence N; Friese, André; Schwarz, Florian; Schauer, Frieder; Portier, Ralph J; Basirico, Laura M; Olson, Gregory M

2016-11-01

Adding clay to marine oil pollution represents a promising approach to enhance bacterial hydrocarbon degradation in nutrient poor waters. In this study, three types of regionally available clays (Ca-bentonite, Fuller's Earth and kaolin) were tested to stimulate the biodegradation of source and weathered oil collected from the Deepwater Horizon spill. The weathered oil showed little biodegradation prior to experimentation and was extensively degraded by bacteria in the laboratory in a similar way as the alkane-rich source oil. For both oils, the addition of natural clay-flakes showed minor enhancement of oil biodegradation compared to the non-clay bearing control, but the clay-oil films did limit evaporation. Only alkanes of a molecular weight (MW) > 420 showed significant reduction by enhanced biodegradation following natural clay treatment. In contrast, all fertilized clay flakes showed major bacterial degradation of the oil, with a 6-10 times reduction in alkane content, and an up to 8 fold increase in the rate of O2 consumption. Compared to the control, such treatment showed particular reduction of longer chained alkanes (MW > 226). The application of natural and fertilized clay flakes also showed selective reduction of PAHs, mainly in the MW range of 200-300, but without significant change in the toxicity indices measured. These results imply that a large variety of clays may be used to boost oil biodegradation by aiding attachment of fertilizing nutrients to the oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fungi benefit from two decades of increased nutrient availability in tundra heath soil.

PubMed

Rinnan, Riikka; Michelsen, Anders; Bååth, Erland

2013-01-01

If microbial degradation of carbon substrates in arctic soil is stimulated by climatic warming, this would be a significant positive feedback on global change. With data from a climate change experiment in Northern Sweden we show that warming and enhanced soil nutrient availability, which is a predicted long-term consequence of climatic warming and mimicked by fertilization, both increase soil microbial biomass. However, while fertilization increased the relative abundance of fungi, warming caused only a minimal shift in the microbial community composition based on the phospholipid fatty acid (PLFA) and neutral lipid fatty acid (NLFA) profiles. The function of the microbial community was also differently affected, as indicated by stable isotope probing of PLFA and NLFA. We demonstrate that two decades of fertilization have favored fungi relative to bacteria, and increased the turnover of complex organic compounds such as vanillin, while warming has had no such effects. Furthermore, the NLFA-to-PLFA ratio for (13)C-incorporation from acetate increased in warmed plots but not in fertilized ones. Thus, fertilization cannot be used as a proxy for effects on warming in arctic tundra soils. Furthermore, the different functional responses suggest that the biomass increase found in both fertilized and warmed plots was mediated via different mechanisms.

DHA and EPA Content and Fatty Acid Profile of 39 Food Fishes from India

PubMed Central

Mahanty, Arabinda; Sankar, T. V.; Anandan, R.; Paul, B. N.; Sarma, Debajit; Syama Dayal, J.; Venkateshwarlu, G.; Mathew, Suseela; Karunakaran, D.; Chanda, Soumen; Shahi, Neetu; Das, Puspita; Das, Partha; Akhtar, Md Shahbaz; Vijayagopal, P.; Sridhar, N.

2016-01-01

Docosahexaenoic acid (DHA) is the principal constituent of a variety of cells especially the brain neurons and retinal cells and plays important role in fetal brain development, development of motor skills, and visual acuity in infants, lipid metabolism, and cognitive support and along with eicosapentaenoic acid (EPA) it plays important role in preventing atherosclerosis, dementia, rheumatoid arthritis, Alzheimer's disease, and so forth. Being an essential nutrient, it is to be obtained through diet and therefore searching for affordable sources of these ω-3 polyunsaturated fatty acids (PUFA) is important for consumer guidance and dietary counseling. Fish is an important source of PUFA and has unique advantage that there are many food fish species available and consumers have a wide choice owing to availability and affordability. The Indian subcontinent harbors a rich fish biodiversity which markedly varies in their nutrient composition. Here we report the DHA and EPA content and fatty acid profile of 39 important food fishes (including finfishes, shellfishes, and edible molluscs from both marine water and freshwater) from India. The study showed that fishes Tenualosa ilisha, Sardinella longiceps, Nemipterus japonicus, and Anabas testudineus are rich sources of DHA and EPA. Promotion of these species as DHA rich species would enhance their utility in public health nutrition. PMID:27579313

DHA and EPA Content and Fatty Acid Profile of 39 Food Fishes from India.

PubMed

Mohanty, Bimal Prasanna; Ganguly, Satabdi; Mahanty, Arabinda; Sankar, T V; Anandan, R; Chakraborty, Kajal; Paul, B N; Sarma, Debajit; Syama Dayal, J; Venkateshwarlu, G; Mathew, Suseela; Asha, K K; Karunakaran, D; Mitra, Tandrima; Chanda, Soumen; Shahi, Neetu; Das, Puspita; Das, Partha; Akhtar, Md Shahbaz; Vijayagopal, P; Sridhar, N

2016-01-01

Docosahexaenoic acid (DHA) is the principal constituent of a variety of cells especially the brain neurons and retinal cells and plays important role in fetal brain development, development of motor skills, and visual acuity in infants, lipid metabolism, and cognitive support and along with eicosapentaenoic acid (EPA) it plays important role in preventing atherosclerosis, dementia, rheumatoid arthritis, Alzheimer's disease, and so forth. Being an essential nutrient, it is to be obtained through diet and therefore searching for affordable sources of these ω-3 polyunsaturated fatty acids (PUFA) is important for consumer guidance and dietary counseling. Fish is an important source of PUFA and has unique advantage that there are many food fish species available and consumers have a wide choice owing to availability and affordability. The Indian subcontinent harbors a rich fish biodiversity which markedly varies in their nutrient composition. Here we report the DHA and EPA content and fatty acid profile of 39 important food fishes (including finfishes, shellfishes, and edible molluscs from both marine water and freshwater) from India. The study showed that fishes Tenualosa ilisha, Sardinella longiceps, Nemipterus japonicus, and Anabas testudineus are rich sources of DHA and EPA. Promotion of these species as DHA rich species would enhance their utility in public health nutrition.

The Influence of Shredder Feeding on Fungal Activity in a Nutrient-Enriched Stream and an Unaltered Stream

NASA Astrophysics Data System (ADS)

Chung, N.; Suberkopp, K.

2005-05-01

The effect of shredder feeding on aquatic hyphomycete communities associated with submerged leaves was studied in two southern Appalachian headwater streams in North Carolina. Coarse and fine mesh litter bags containing red maple (Acer rubrum) leaves were placed in the nutrient-enriched stream and in the reference stream and were retrieved monthly. Both shredder feeding and nutrient enrichment enhanced breakdown rates. The breakdown rates of leaves in coarse mesh bags in the reference stream (k = 0.0275) and fine mesh bags in the nutrient enriched stream (k = 0.0272) were not significantly different, suggesting that the shredding effect on litter breakdown was offset by higher fungal activity as a result of nutrient enrichment. Fungal sporulation rates and biomass (based on ergosterol concentrations) were higher in the nutrient enriched than in the reference stream, but neither fungal biomass nor sporulation rate was affected by shredder feeding. Species richness was higher in the nutrient-enriched than in the reference stream. The enrichment with nutrients altered fungal community composition more than shredder feeding.

The combined effects of sediment accretion (burial) and nutrient enrichment on the growth and propagation of Phalaris arundinacea

PubMed Central

Chen, Xinsheng; Liao, Yulin; Xie, Yonghong; Wu, Chao; Li, Feng; Deng, Zhengmiao; Li, Xu

2017-01-01

Sediment accretion (burial) and nutrient enrichment occur concurrently in lacustrine wetlands, but the role of these two aspects of sedimentation on macrophyte performance has rarely been examined. Here, we investigated the concurrent effects of sediment accretion and nutrient enrichment on the growth and propagation of Phalaris arundinacea L. using a factorial sediment burial by nutrient addition experimental design. Regardless of burial depth, nutrient addition increased biomass accumulation, shoot mass ratio, the number of rhizomes, and the length of ramets and rhizomes. While burial had little effect on plant growth and propagation, it had an interactive effect with nutrient addition on belowground growth and ramet production. These results indicate that P. arundinacea is tolerant to burial, which allows it to grow in habitats with high sedimentation rates. However, the enhanced growth and propagation of P. arundinacea following sedimentation were primarily related to nutrient enrichment. This suggests that nutrient enrichment of sediments, which occurs in many lacustrine wetlands, increases the risk of invasion by P. arundinacea. PMID:28054590

Exploring the efficacy of wastewater-grown microalgal biomass as a biofertilizer for wheat.

PubMed

Renuka, Nirmal; Prasanna, Radha; Sood, Anjuli; Ahluwalia, Amrik S; Bansal, Radhika; Babu, Santosh; Singh, Rajendra; Shivay, Yashbir S; Nain, Lata

2016-04-01

Microalgae possess the ability to grow and glean nutrients from wastewater; such wastewater-grown biomass can be used as a biofertilizer for crops. The present investigation was undertaken to evaluate two formulations (formulation with unicellular microalgae (MC1) and formulation with filamentous microalgae (MC2); T4 and T5, respectively), prepared using wastewater-grown microalgal biomass, as a biofertilizer (after mixing with vermiculite/compost as a carrier) in wheat crop (Triticum aestivum L. HD2967) under controlled conditions. The highest values of available nitrogen (N), phosphorus (P), and potassium (K) in soil and nitrogen-fixing potential were recorded in treatment T5 (75% N + full-dose PK + formulation with filamentous microalgae (MC2). Microbial biomass carbon was significantly enhanced by 31.8-67.0% in both the inoculated treatments over control (recommended dose of fertilizers), with highest values in T4 (75% N + full-dose PK + formulation with unicellular microalgae (MC1)). Both the microalgal formulations significantly increased the N, P, and K content of roots, shoots, and grains, and the highest total N content of 3.56% in grains was observed in treatment T5. At harvest stage, the treatments inoculated with microalgal formulations (T4 and T5) recorded a 7.4-33% increase in plant dry weight and up to 10% in spike weight. The values of 1000-grain weight showed an enhancement of 5.6-8.4%, compared with T1 (recommended doses of fertilizers). A positive correlation was observed between soil nutrient availability at mid crop stage and plant biometrical parameters at harvest stage. This study revealed the promise of such microalgal consortia as a biofertilizer for 25% N savings and improved yields of wheat crop.

Selective dissolution followed by EDDS washing of an e-waste contaminated soil: Extraction efficiency, fate of residual metals, and impact on soil environment.

PubMed

Beiyuan, Jingzi; Tsang, Daniel C W; Valix, Marjorie; Zhang, Weihua; Yang, Xin; Ok, Yong Sik; Li, Xiang-Dong

2017-01-01

To enhance extraction of strongly bound metals from oxide minerals and organic matter, this study examined the sequential use of reductants, oxidants, alkaline solvents and organic acids followed by a biodegradable chelating agent (EDDS, [S,S]-ethylene-diamine-disuccinic-acid) in a two-stage soil washing. The soil was contaminated by Cu, Zn, and Pb at an e-waste recycling site in Qingyuan city, China. In addition to extraction efficiency, this study also examined the fate of residual metals (e.g., leachability, bioaccessibility, and distribution) and the soil quality parameters (i.e., cytotoxicity, enzyme activities, and available nutrients). The reductants (dithionite-citrate-bicarbonate and hydroxylamine hydrochloride) effectively extracted metals by mineral dissolution, but elevated the leachability and bioaccessibility of metals due to the transformation from Fe/Mn oxides to labile fractions. Subsequent EDDS washing was found necessary to mitigate the residual risks. In comparison, prior washing by oxidants (persulphate, hypochlorite, and hydrogen peroxide) was marginally useful because of limited amount of soil organic matter. Prior washing by alkaline solvents (sodium hydroxide and sodium bicarbonate) was also ineffective due to metal precipitation. In contrast, prior washing by low-molecular-weight organic acids (citrate and oxalate) improved the extraction efficiency. Compared to hydroxylamine hydrochloride, citrate and oxalate induced lower cytotoxicity (Microtox) and allowed higher enzyme activities (dehydrogenase, acid phosphatase, and urease) and soil nutrients (available nitrogen and phosphorus), which would facilitate reuse of the treated soil. Therefore, while sequential washing proved to enhance extraction efficacy, the selection of chemical agents besides EDDS should also include the consideration of effects on metal leachability/bioaccessibility and soil quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of nitrogen additions on litter decomposition, nutrient dynamics, and enzymatic activity of two plant species in a peatland in Northeast China.

PubMed

Song, Yanyu; Song, Changchun; Ren, Jiusheng; Tan, Wenwen; Jin, Shaofei; Jiang, Lei

2018-06-01

Nitrogen (N) availability affects litter decomposition and nutrient dynamics, especially in N-limited ecosystems. We investigated the response of litter decomposition to N additions in Eriophorum vaginatum and Vaccinium uliginosum peatlands. These two species dominate peatlands in Northeast China. In 2012, mesh bags containing senesced leaf litter of Eriophorum vaginatum and Vaccinium uliginosum were placed in N addition plots and sprayed monthly for two years with NH 4 NO 3 solution at dose rates of 0, 6, 12, and 24gNm -2 year -1 (CK, N1, N2 and N3, respectively). Mass loss, N and phosphorus (P) content, and enzymatic activity were measured over time as litter decomposed. In the control plots, V. uliginosum litter decomposed faster than E. vaginatum litter. N1, N2, and N3 treatments increased the mass losses of V. uliginosum litter by 6%, 9%, and 4% respectively, when compared with control. No significant influence of N additions was found on the decomposition of E. vaginatum litter. However, N and P content in E. vaginatum litter and V. uliginosum litter significantly increased with N additions. Moreover, N additions significantly promoted invertase and β-glucosidase activity in E. vaginatum and V. uliginosum litter. However, only in V. uliginosum litter was polyphenol oxidase activity significantly enhanced. Our results showed that initial litter quality and polyphenol oxidase activity influence the response of plant litter to N additions in peatland ecosystems. Increased N availability may change peatland soil N and P cycling by enhancing N and P immobilization during litter decomposition. Copyright © 2018 Elsevier B.V. All rights reserved.

Genetic diversity enhances the resistance of a seagrass ecosystem to disturbance.

PubMed

Hughes, A Randall; Stachowicz, John J

2004-06-15

Motivated by recent global reductions in biodiversity, empirical and theoretical research suggests that more species-rich systems exhibit enhanced productivity, nutrient cycling, or resistance to disturbance or invasion relative to systems with fewer species. In contrast, few data are available to assess the potential ecosystem-level importance of genetic diversity within species known to play a major functional role. Using a manipulative field experiment, we show that increasing genotypic diversity in a habitat-forming species (the seagrass Zostera marina) enhances community resistance to disturbance by grazing geese. The time required for recovery to near predisturbance densities also decreases with increasing eelgrass genotypic diversity. However, there is no effect of diversity on resilience, measured as the rate of shoot recovery after the disturbance, suggesting that more rapid recovery in diverse plots is due solely to differences in disturbance resistance. Genotypic diversity did not affect ecosystem processes in the absence of disturbance. Thus, our results suggest that genetic diversity, like species diversity, may be most important for enhancing the consistency and reliability of ecosystems by providing biological insurance against environmental change.

Recent developments in biochar utilization as an additive in organic solid waste composting: A review.

PubMed

Xiao, Ran; Awasthi, Mukesh Kumar; Li, Ronghua; Park, Jonghwan; Pensky, Scott M; Wang, Quan; Wang, Jim J; Zhang, Zengqiang

2017-12-01

In recent years, considerable studies have been devoted to investigating the effect of biochar application on organic solid waste composting. This review provides an up-to-date overview of biochar amendment on composting processes and compost quality. Biochar production, characteristics, and its application coupled with the basic concepts of composting are briefly introduced before detailing the effects of biochar addition on composting. According to recent studies, biochar has exhibited great potential for enhancing composting. It is evident that biochar addition in composting can: (1) improve compost mixture physicochemical properties, (2) enhance microbial activities and promote organic matter decomposition, (3) reduce ammonia (NH 3 ) and greenhouse gas (GHG) emissions, and (4) upgrade compost quality by increasing the total/available nutrient content, enhancing maturity, and decreasing phytotoxicity. Despite that, further research is needed to explore the mechanism of biochar addition on composting and to evaluate the agricultural and environmental performances of co-composted biochar compost. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Governor has a sweet tooth - mouth sensing of nutrients to enhance sports performance.

PubMed

Burke, Louise M; Maughan, Ronald J

2015-01-01

The oral-pharyngeal cavity and the gastrointestinal tract are richly endowed with receptors that respond to taste, temperature and to a wide range of specific nutrient and non-nutritive food components. Ingestion of carbohydrate-containing drinks has been shown to enhance endurance exercise performance, and these responses have been attributed to post-absorptive effects. It is increasingly recognised, though, that the response to ingested carbohydrate begins in the mouth via specific carbohydrate receptors and continues in the gut via the release of a range of hormones that influence substrate metabolism. Cold drinks can also enhance performance, especially in conditions of thermal stress, and part of the mechanism underlying this effect may be the response to cold fluids in the mouth. There is also some, albeit not entirely consistent, evidence for effects of caffeine, quinine, menthol and acetic acid on performance or other relevant effects. This review summarises current knowledge of responses to mouth sensing of temperature, carbohydrate and other food components, with the goal of assisting athletes to implement practical strategies that make best use of its effects. It also examines the evidence that oral intake of other nutrients or characteristics associated with food/fluid intake during exercise can enhance performance via communication between the mouth/gut and the brain.

Volcanic ash as a driver of enhanced organic carbon burial in the Cretaceous.

PubMed

Lee, Cin-Ty A; Jiang, Hehe; Ronay, Elli; Minisini, Daniel; Stiles, Jackson; Neal, Matthew

2018-03-08

On greater than million year timescales, carbon in the ocean-atmosphere-biosphere system is controlled by geologic inputs of CO 2 through volcanic and metamorphic degassing. High atmospheric CO 2 and warm climates in the Cretaceous have been attributed to enhanced volcanic emissions of CO 2 through more rapid spreading at mid-ocean ridges and, in particular, to a global flare-up in continental arc volcanism. Here, we show that global flare-ups in continental arc magmatism also enhance the global flux of nutrients into the ocean through production of windblown ash. We show that up to 75% of Si, Fe and P is leached from windblown ash during and shortly after deposition, with soluble Si, Fe and P inputs from ash alone in the Cretaceous being higher than the combined input of dust and rivers today. Ash-derived nutrient inputs may have increased the efficiency of biological productivity and organic carbon preservation in the Cretaceous, possibly explaining why the carbon isotopic signature of Cretaceous seawater was high. Variations in volcanic activity, particularly continental arcs, have the potential of profoundly altering carbon cycling at the Earth's surface by increasing inputs of CO 2 and ash-borne nutrients, which together enhance biological productivity and burial of organic carbon, generating an abundance of hydrocarbon source rocks.

The effect of herbicide application on rangeland soil nutrient availability

USDA-ARS?s Scientific Manuscript database

Very sparse literature exists on the effect of soil active herbicides on nutrient availability. As part of a larger rangeland rehabilitation project, on four sites in northern Nevada, we quantified the effect of the herbicides Landmark®, Perspective®, and Plateau® relative to controls on surface soi...

Nutrient source and tillage influences on nitrogen availability in a Southern Piedmont corn cropping system

USDA-ARS?s Scientific Manuscript database

Combinations of conservation tillage and poultry litter (PL) can increase crop production in southeastern USA soils compared to conventional tillage (CT) and chemical fertilizer (CF). The reason for the beneficial response is usually attributed to improved water and nutrient availability. We evaluat...

Effects of Phos-Chek® on soil nutrient availability

USDA-ARS?s Scientific Manuscript database

Wildfire frequencies and intensities have been steadily increasing on western US landscapes. Phos-chek® is an aerially-applied fire retardant used to contain and control wildfires. Composed of ammonium and phosphate salts, Phos-chek® has the potential to increase soil nutrient availability of N and ...

Effect of temperature and nutrients on the growth and development of seedlings of an invasive plant.

PubMed

Skálová, Hana; Moravcová, Lenka; Dixon, Anthony F G; Kindlmann, P; Pyšek, Petr

2015-04-28

Plant species distributions are determined by the response of populations to regional climates; however, little is known about how alien plants that arrive in central Europe from climatically warmer regions cope with the temperature conditions at the early stage of population development. Ambrosia artemisiifolia (common ragweed) is an invasive annual plant causing considerable health and economic problems in Europe. Although climate-based models predict that the whole of the Czech Republic is climatically suitable for this species, it is confined to the warmest regions. To determine the factors possibly responsible for its restricted occurrence, we investigated the effects of temperature and nutrient availability on its seedlings. The plants were cultivated at one of seven temperature regimes ranging from 10 to 34 °C, combined with three nutrient levels. The data on the rate of leaf development were used to calculate the lower developmental threshold (LDT, the temperature, in °C, below which development ceases), the sum of effective temperatures (SET, the amount of heat needed to complete a developmental stage measured in degree days above LDT) and width of the thermal window. The rate of development decreased with decrease in temperature and nutrient supply. Besides this, the decrease in the availability of nutrients resulted in decreased LDT, increased SET and wider thermal window. The dependence of LDT and SET on the availability of nutrients contradicts the concept that thermal constants do not vary. Our results highlight temperature as the main determinant of common ragweed's distribution and identify nutrient availability as a factor that results in the realized niche being smaller than the fundamental niche; both of these need to be taken into account when predicting the future spread of A. artemisiifolia. Published by Oxford University Press on behalf of the Annals of Botany Company.

A nonpathogenic Fusarium oxysporum strain enhances phytoextraction of heavy metals by the hyperaccumulator Sedum alfredii Hance.

PubMed

Zhang, Xincheng; Lin, Li; Chen, Mingyue; Zhu, Zhiqiang; Yang, Weidong; Chen, Bao; Yang, Xiaoe; An, Qianli

2012-08-30

Low biomass and shallow root systems limit the application of heavy metal phytoextraction by hyperaccumulators. Plant growth-promoting microbes may enhance hyperaccumulators'phytoextraction. A heavy metal-resistant fungus belonged to the Fusarium oxysporum complex was isolated from the Zn/Cd co-hyperaccumulator Sedum alfredii Hance grown in a Pb/Zn mined area. This Fusarium fungus was not pathogenic to plants but promoted host growth. Hydroponic experiments showed that 500 μM Zn(2+) or 50 μM Cd(2+) combined with the fungus increased root length, branches, and surface areas, enhanced nutrient uptake and chlorophyll synthesis, leading to more vigorous hyperaccumulators with greater root systems. Soil experiments showed that the fungus increased root and shoot biomass and S. alfredii-mediated heavy metal availabilities, uptake, translocation or concentrations, and thus increased phytoextraction of Zn (144% and 44%), Cd (139% and 55%), Pb (84% and 85%) and Cu (63% and 77%) from the original Pb/Zn mined soil and a multi-metal contaminated paddy soil. Together, the nonpathogenic Fusarium fungus was able to increase S. alfredii root systems and function, metal availability and accumulation, plant biomass, and thus phytoextraction efficiency. This study showed a great application potential for culturable indigenous fungi other than symbiotic mycorrhizas to enhance the phytoextraction by hyperaccumulators. Copyright © 2012 Elsevier B.V. All rights reserved.

X-ray fluorescence spectrometry-based approach to precision management of bioavailable phosphorus in soil environments

USDA-ARS?s Scientific Manuscript database

Declining nutrient use efficiency in crop production has been a global priority to preserve high agricultural productivity with finite non-renewable nutrient resources, in particular phosphorus (P). Rapid spectroscopic methods increase measurement density of soil nutrients, and the availability of ...

Combined Influence of Landscape Composition and Nutrient Inputs on Lake Trophic Structure

EPA Science Inventory

The concentration of chlorophyll a is a measure of the biological productivity of a lake and is largely (but not exclusively) determined by available nutrients. As nutrient inputs increase, productivity increases and lakes transition from low trophic state (e.g. oligotrophic) to...

Measuring nutrient flux in Pacific Coast salt marshes using fluctuating water-level chambers

EPA Science Inventory

Nutrient removal from the water column is an important ecosystem function that contributes to the production of clean water, a final valued ecosystem service of wetlands. However, little data is currently available for nutrient exchange in Pacific Northwest tidal ecosystems. We h...

Integrated plant nutrient system - with special emphasis on mineral nutriton and biofertilizers for Black pepper and cardamom - A review.

PubMed

K P, Sangeeth; R, Suseela Bhai

2016-05-01

Integrated Plant Nutrition System (IPNS) as a concept and farm management strategy embraces and transcends from single season crop fertilization efforts to planning and management of plant nutrients in crop rotations and farming systems on a long-term basis for enhanced productivity, profitability and sustainability. It is estimated that about two-thirds of the required increase in crop production in developing countries will have to come from yield increases from lands already under cultivation. IPNS enhances soil productivity through a balanced use of soil nutrients, chemical fertilizers, combined with organic sources of plant nutrients, including bio-inoculants and nutrient transfer through agro-forestry systems and has adaptation to farming systems in both irrigated and rainfed agriculture. Horticultural crops, mainly plantation crops, management practices include application of fertilizers and pesticides which become inevitable due to the depletion of soil organic matter and incidence of pests and diseases. The extensive use of chemical fertilizers in these crops deteriorated soil health that in turn affected the productivity. To revitalize soil health and to enhance productivity, it is inexorable to enrich the soil using microorganisms. The lacunae observed here is the lack of exploitation of indigenous microbes having the potential to fix atmospheric nitrogen (N) and to solubilize Phosphorus (P) and Potassium (K). The concept of biofertilizer application appears to be technically simple and financially feasible, but the task of developing biofertilizers with efficient strains in appropriate combinations in a consortia mode is not easier. More than developing consortia, a suitable delivery system to discharge the microbial inoculants warranted much effort. This review focuses on the integrated plant nutrition system incorporating biofertilizer with special emphasis on developing and formulating biofertilizer consortium.

Buffering and Amplifying Interactions among OAW (Ocean Acidification & Warming) and Nutrient Enrichment on Early Life-Stage Fucus vesiculosus L. (Phaeophyceae) and Their Carry Over Effects to Hypoxia Impact.

PubMed

Al-Janabi, Balsam; Kruse, Inken; Graiff, Angelika; Winde, Vera; Lenz, Mark; Wahl, Martin

2016-01-01

Ocean acidification and warming (OAW) are occurring globally. Additionally, at a more local scale the spreading of hypoxic conditions is promoted by eutrophication and warming. In the semi-enclosed brackish Baltic Sea, occasional upwelling in late summer and autumn may expose even shallow-water communities including the macroalga Fucus vesiculosus to particularly acidified, nutrient-rich and oxygen-poor water bodies. During summer 2014 (July-September) sibling groups of early life-stage F. vesiculosus were exposed to OAW in the presence and absence of enhanced nutrient levels and, subsequently to a single upwelling event in a near-natural scenario which included all environmental fluctuations in the Kiel Fjord, southwestern Baltic Sea, Germany (54°27 ´N, 10°11 ´W). We strove to elucidate the single and combined impacts of these potential stressors, and how stress sensitivity varies among genetically different sibling groups. Enhanced by a circumstantial natural heat wave, warming and acidification increased mortalities and reduced growth in F. vesiculosus germlings. This impact, however, was mitigated by enhanced nutrient conditions. Survival under OAW conditions strongly varied among sibling groups hinting at a substantial adaptive potential of the natural Fucus populations in the Western Baltic. A three-day experimental upwelling caused severe mortality of Fucus germlings, which was substantially more severe in those sibling groups which previously had been exposed to OAW. Our results show that global (OAW), regional (nutrient enrichment) and local pressures (upwelling), both alone and co-occurring may have synergistic and antagonistic effects on survival and/or growth of Fucus germlings. This result emphasizes the need to consider combined stress effects.

An analysis of the breakdown of paper products (toilet paper, tissues and tampons) in natural environments, Tasmania, Australia.

PubMed

Bridle, Kerry L; Kirkpatrick, J B

2005-01-01

An examination of the relative breakdown rates of unused toilet paper, facial tissues and tampons was undertaken in nine different environments typical of Tasmanian natural areas. Bags of the paper products (toilet paper, facial tissues, tampons) were buried for periods of 6, 12 and 24 months at depths of 5 and 15 cm. A nutrient solution simulating human body wastes was added to half of the samples, to test the hypothesis that the addition of nutrients would enhance the breakdown of paper products buried in the soil. Mean annual rainfall was the most important measured variable determining mean breakdown in the nutrient addition treatment between sites, with high rainfall sites (mean annual rainfall of greater than 650 mm) recording less decayed products than the drier sites (mean annual rainfall of 500-650 mm). Temperature and soil organic content were important influences on the breakdown of the unfertilised products. Toilet paper and tissues decayed more readily than tampons. Nutrient addition enhanced decay for all products across all sites. Depth of burial was not important in determining the degree to which products decayed. In alpine environments, burial under rocks at the surface did not increase the speed of decay of any product. The Western Alpine site, typical of alpine sites in the Tasmanian Wilderness World Heritage Area, showed very little decay over the two-year period, even for nutrient enhanced products. Management prescriptions should be amended to dissuade people from depositing human toilet waste in the extreme (montane to alpine) environments in western Tasmania. Tampons should continue to be carried out as currently prescribed.

The Good, the Bad and the Ugly - Interacting Physical, Biogeochemical and Biolological Controls of Nutrient Cycling at Ecohydrological Interfaces

NASA Astrophysics Data System (ADS)

Krause, S.; Baranov, V. A.; Lewandowski, J.; Blaen, P. J.; Romeijn, P.

2016-12-01

The interfaces between streams, lakes and their bed sediments have for a long time been in the research focus of ecohydrologists, aquatic ecologists and biogeochemists. While over the past decades, critical understanding has been gained of the spatial patterns and temporal dynamics in nutrient cycling at sediment-freshwater interfaces, important question remain as to the actual drivers (physical, biogeochemical and biological) of the often observed hot spots and hot moments of nutrient cycling at these highly reactive systems. This study reports on a combination of laboratory manipulation, artificial stream and field experiments from reach to river network scales to investigate the interplay of physical, biogeochemical and biological drivers of interface nutrient cycling under the impact of and resilience to global environmental change. Our results indicate that biogeochemical hotspots at sediment-freshwater interfaces were controlled not only by reactant mixing ratios and residence time distributions, but strongly affected by patterns in streambed physical properties and bioavailability of organic carbon. Lab incubation experiments revealed that geology, and in particular organic matter content strongly controlled the magnitude of enhanced streambed greenhouse gas production caused by increasing water temperatures. While these findings help to improve our understanding of physical and biogeochemical controls on nutrient cycling, we only start to understand to what degree biological factors can enhance these processes even further. We found that for instance chironomid or brittle star facilitated bioturbation in has the potential to substantially enhance freshwater or marine sediment pore-water flow and respiration. We revealed that ignorance of these important biologically controls on physical exchange fluxes can lead to critical underestimation of whole system respiration and its increase under global environmental change.

The influence of arbuscular mycorrhizae on root precision nutrient foraging of two pioneer plant species during early reclamation

NASA Astrophysics Data System (ADS)

Boldt-Burisch, Katja; Naeth, M. Anne

2017-04-01

On many post mining sites in the Lusatian Mining District (East Germany) soil heterogeneity consists of sandy soil with embedded clay-silt fragments. Those clays silt fragments might act as nutrient hotspots. Arbuscular mycorrhizal fungi in an infertile ecosystem could enhance a plant's ability to selectively forage for those nutrients and thus to improve plants nutrient supply. In our study we investigated whether silt-clay fragments within a sandy soil matrix induced preferential root growth of Lotus corniculatus and Calamagrostis epigeios, whether arbuscular mycorrhizae influenced root foraging patterns, and to what extent selective rooting in clay silt fragments influenced plant growth were addressed in this research. Soil types were sterile and non-sterile sandy soil and clay-silt fragments. Treatments were with and without arbuscular mycorrhizae, with and without soil solution, and soil solution and mycorrhizal inoculum combined. Root biomass, root density and intraradical fungal alkaline phosphatase activity and frequency were determined in fragments relative to sandy soil. Furthermore, temporal relationship of number of roots in fragments and plant height was assessed. Lotus corniculatus showed strong selective rooting into fragments especially with those plants treated with commercial cultivated arbuscular mycorrhizae; Calamagrostis epigeios did not. Without arbuscular mycorrhizae, L. corniculatus growth was significantly reduced and selective rooting did not occur. Selective rooting induced significant growth spurts of L. corniculatus. Roots in fragments had higher fungal alkaline phosphatase activity suggesting that mycorrhizal efficiency and related plants phosphorus supply is enhanced in roots in fragments. The application of cultivated arbuscular mycorrhizal fungi significantly and quickly influenced root foraging patterns, especially those of L. corniculatus, suggesting mycorrhizae may also enhance the ability of other plants to selectively forage for nutrients and could therefore play an important role in early plant establishment on infertile reclamation sites.

Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis.

PubMed

Zhou, Qiongzhi; Li, Feng; Ge, Fei; Liu, Na; Kuang, Yangduo

2016-10-01

Toxicants are generally harmful to biotechnology in wastewater treatment. However, trace toxicant can induce microbial hormesis, but to date, it is still unknown how this phenomenon affects nutrient removal during municipal wastewater treatment process. Therefore, this study focused on the effects of hormesis induced by cetyltrimethyl ammonium bromide (CTAB), a representative quaternary ammonium cationic surfactant, on nutrient removal by Chlorella vulgaris F1068. Results showed that when the concentration of CTAB was less than 10 ng/L, the cellular components chlorophyll a, proteins, polysaccharides, and total lipids increased by 10.11, 58.17, 38.78, and 11.87 %, respectively, and some enzymes in nutrient metabolism of algal cells, such as glutamine synthetase (GS), acid phosphatase (ACP), H(+)-ATPase, and esterase, were also enhanced. As a result, the removal efficiencies of ammonia nitrogen (NH4 (+)) and total phosphorus (TP) increased by 14.66 and 8.51 %, respectively, compared to the control during a 7-day test period. The underlying mechanism was mainly due to an enhanced photosynthetic activity of C. vulgaris F1068 indicated by the increase in chlorophyll fluorescence parameters (the value of Fv/Fm, ΦII, Fv/Fo, and rETR increased by 12.99, 7.56, 25.59, and 8.11 %, respectively) and adenylate energy charge (AEC) (from 0.68 to 0.72). These results suggest that hormesis induced by trace toxicants could enhance the nutrient removal, which would be further considered in the design of municipal wastewater treatment processes. Graphical abstract The schematic mechanism of C. vulgaris F1068 under CTAB induced hormesis. Green arrows ( ) represent the increase and the red arrow ( ) represents the decrease.

Effect of acclimation and nutrient supply on 5-tolyltriazole biodegradation with activated sludge communities.

PubMed

Herzog, Bastian; Yuan, Heyang; Lemmer, Hilde; Horn, Harald; Müller, Elisabeth

2014-07-01

The corrosion inhibitor 5-tolyltriazole (5-TTri) can have a detrimental impact on aquatic systems thus implying an acute need to reduce the effluent concentrations of 5-TTri. In this study, 5-TTri biodegradation was enhanced through acclimation and nutrient supply. Activated sludge communities (ASC) were setup in nine subsequent ASC generations. While generation two showed a lag phase of five days without biodegradation, generations four to nine utilized 5-TTri right after inoculation, with biodegradation rates from 3.3 to 5.2 mg L(-1)d(-1). Additionally, centrifuged AS supernatant was used to simulate the nutrient conditions in wastewater. This sludge supernatant (SS) significantly enhanced biodegradation, resulting in removal rates ranging from 3.2 to 5.0 mg L(-1)d(-1) without acclimation while the control groups without SS observed lower rates of ⩽ 2.2 mg L(-1)d(-1). Copyright © 2014 Elsevier Ltd. All rights reserved.

Balancing carbon/nitrogen ratio to improve nutrients removal and algal biomass production in piggery and brewery wastewaters.

PubMed

Zheng, Hongli; Liu, Mingzhi; Lu, Qian; Wu, Xiaodan; Ma, Yiwei; Cheng, Yanling; Addy, Min; Liu, Yuhuan; Ruan, Roger

2018-02-01

To improve nutrients removal from wastewaters and enhance algal biomass production, piggery wastewater was mixed with brewery wastewaters. The results showed that it was a promising way to cultivate microalga in piggery and brewery wastewaters by balancing the carbon/nitrogen ratio. The optimal treatment condition for the mixed piggery-brewery wastewater using microalga was piggery wastewater mixed with brewery packaging wastewater by 1:5 at pH 7.0, resulting in carbon/nitrogen ratio of 7.9, with the biomass concentration of 2.85 g L -1 , and the removal of 100% ammonia, 96% of total nitrogen, 90% of total phosphorus, and 93% of chemical oxygen demand. The application of the established strategies can enhance nutrient removal efficiency of the wastewaters while reducing microalgal biomass production costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Freshwater bacterioplankton richness in oligotrophic lakes depends on nutrient availability rather than on species–area relationships

PubMed Central

Logue, Jürg Brendan; Langenheder, Silke; Andersson, Anders F; Bertilsson, Stefan; Drakare, Stina; Lanzén, Anders; Lindström, Eva S

2012-01-01

A central goal in ecology is to grasp the mechanisms that underlie and maintain biodiversity and patterns in its spatial distribution can provide clues about those mechanisms. Here, we investigated what might determine the bacterioplankton richness (BR) in lakes by means of 454 pyrosequencing of the 16S rRNA gene. We further provide a BR estimate based upon a sampling depth and accuracy, which, to our knowledge, are unsurpassed for freshwater bacterioplankton communities. Our examination of 22 669 sequences per lake showed that freshwater BR in fourteen nutrient-poor lakes was positively influenced by nutrient availability. Our study is, thus, consistent with the finding that the supply of available nutrients is a major driver of species richness; a pattern that may well be universally valid to the world of both micro- and macro-organisms. We, furthermore, observed that BR increased with elevated landscape position, most likely as a consequence of differences in nutrient availability. Finally, BR decreased with increasing lake and catchment area that is negative species–area relationships (SARs) were recorded; a finding that re-opens the debate about whether positive SARs can indeed be found in the microbial world and whether positive SARs can in fact be pronounced as one of the few ‘laws' in ecology. PMID:22170419

Assessing Marine Microbial Induced Corrosion at Santa Catalina Island, California

PubMed Central

Ramírez, Gustavo A.; Hoffman, Colleen L.; Lee, Michael D.; Lesniewski, Ryan A.; Barco, Roman A.; Garber, Arkadiy; Toner, Brandy M.; Wheat, Charles G.; Edwards, Katrina J.; Orcutt, Beth N.

2016-01-01

High iron and eutrophic conditions are reported as environmental factors leading to accelerated low-water corrosion, an enhanced form of near-shore microbial induced corrosion. To explore this hypothesis, we deployed flow-through colonization systems in laboratory-based aquarium tanks under a continuous flow of surface seawater from Santa Catalina Island, CA, USA, for periods of 2 and 6 months. Substrates consisted of mild steel – a major constituent of maritime infrastructure – and the naturally occurring iron sulfide mineral pyrite. Four conditions were tested: free-venting “high-flux” conditions; a “stagnant” condition; an “active” flow-through condition with seawater slowly pumped over the substrates; and an “enrichment” condition where the slow pumping of seawater was supplemented with nutrient rich medium. Electron microscopy analyses of the 2-month high flux incubations document coating of substrates with “twisted stalks,” resembling iron oxyhydroxide bioprecipitates made by marine neutrophilic Fe-oxidizing bacteria (FeOB). Six-month incubations exhibit increased biofilm and substrate corrosion in the active flow and nutrient enriched conditions relative to the stagnant condition. A scarcity of twisted stalks was observed for all 6 month slow-flow conditions compared to the high-flux condition, which may be attributable to oxygen concentrations in the slow-flux conditions being prohibitively low for sustained growth of stalk-producing bacteria. All substrates developed microbial communities reflective of the original seawater input, as based on 16S rRNA gene sequencing. Deltaproteobacteria sequences increased in relative abundance in the active flow and nutrient enrichment conditions, whereas Gammaproteobacteria sequences were relatively more abundant in the stagnant condition. These results indicate that (i) high-flux incubations with higher oxygen availability favor the development of biofilms with twisted stalks resembling those of marine neutrophilic FeOB and (ii) long-term nutrient stimulation results in substrate corrosion and biofilms with different bacterial community composition and structure relative to stagnant and non-nutritionally enhanced incubations. Similar microbial succession scenarios, involving increases in nutritional input leading to the proliferation of anaerobic iron and sulfur-cycling guilds, may occur at the nearby Port of Los Angeles and cause potential damage to maritime port infrastructure. PMID:27826293

Pyrolysis of attapulgite clay blended with yak dung enhances pasture growth and soil health: Characterization and initial field trials.

PubMed

Rafiq, Muhammad Khalid; Joseph, Stephen D; Li, Fei; Bai, Yanfu; Shang, Zhanhuan; Rawal, Aditya; Hook, James M; Munroe, Paul R; Donne, Scott; Taherymoosavi, Sara; Mitchell, David R G; Pace, Ben; Mohammed, Mohanad; Horvat, Joseph; Marjo, Christopher E; Wagner, Avital; Wang, Yanlong; Ye, Jun; Long, Rui-Jun

2017-12-31

Recent studies have shown that the pyrolysis of biomass combined with clay can result in both lower cost and increase in plant yields. One of the major sources of nutrients for pasture growth, as well as fuel and building materials in Tibet is yak dung. This paper reports on the initial field testing in a pasture setting in Tibet using yak dung, biochar, and attapulgite clay/yak dung biochars produced at ratios of 10/90 and 50/50 clay to dung. We found that the treatment with attapulgite clay/yak dung (50/50) biochar resulted in the highest pasture yields and grass nutrition quality. We also measured the properties and yields of mixtures of clay/yak dung biochar used in the field trials produced at 400°C and 500°C to help determine a possible optimum final pyrolysis temperature and dung/clay ratio. It was observed that increasing clay content increased carbon stability, overall biochar yield, pore size, carboxyl and ketone/aldehyde functional groups, hematite and ferrous/ferric sulphate/thiosulphate concentration, surface area and magnetic moment. Decreasing clay content resulted in higher pH, CEC, N content and an enhanced ability to accept and donate electrons. The resulting properties were a complex function of both processing temperature and the percentage of clay for the biochars processed at both 400°C and 500°C. It is possible that the increase in yield and nutrient uptake in the field trial is related to the higher concentration of C/O functional groups, higher surface area and pore volume and higher content of Fe/O/S nanoparticles of multiple oxidation state in the 50/50 clay/dung. These properties have been found to significantly increase the abundance of beneficial microorganisms and hence improve the nutrient cycling and availability in soil. Further field trials are required to determine the optimum pyrolysis production conditions and application rate on the abundance of beneficial microorganisms, yields and nutrient quality. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of available nitrogen on phytoavailability and bioaccumulation of hexavalent and trivalent chromium in hankow willows (Salix matsudana Koidz).

PubMed

Yu, Xiao-Zhang; Gu, Ji-Dong

2008-06-01

The effect of available nitrogen in nutrient solution on removal of two chemical forms of chromium (Cr) by plants was investigated. Pre-rooted hankow willows (Salix matsudana Koidz) were grown in a hydroponic solution system with or without nitrogen, and amended with hexavalent chromium [Cr (VI)] or trivalent chromium [Cr (III)] at 25.0+/-0.5 degrees C for 192 h. The results revealed that higher removal of Cr by plants was achieved from the hydroponic solutions without any nitrogen than those containing nitrogen. Although faster removal of Cr (VI) than Cr (III) was observed, translocation of Cr (III) within plant materials was more efficient than Cr (VI). Substantial difference existed in the distribution of Cr in different parts of plant tissues due to the nitrogen in nutrient solutions (p<0.05): lower stems were the major sink for both Cr species in willows grown in the N-free nutrient solutions and more Cr was accumulated in the roots of plants in N-containing ones. No significant difference was found in the removal rate of Cr (VI) between willows grown in the N-free and N-containing solutions (p>0.05). Removal rates of Cr (III) decreased linearly with the strength of nutrient solutions with or without N addition (p<0.01). Translocation efficiencies of both Cr species increased proportionally with the strength of N-containing nutrient solutions and decreased with the strength of N-free nutrient solutions. Results suggest that uptake and translocation mechanisms of Cr (VI) and Cr (III) are apparently different in hankow willows. The presence of easily available nitrogen and other nutrient elements in the nutrient solutions had a more pronounced influence on the uptake of Cr (III) than Cr (VI). Nitrogen availability and quantities in the ambient environment will affect the translocation of both Cr species and their distribution in willows in phytoremediation.

USA Nutrient managment forecasting via the "Fertilizer Forecaster": linking surface runnof, nutrient application and ecohydrology.

NASA Astrophysics Data System (ADS)

Drohan, Patrick; Buda, Anthony; Kleinman, Peter; Miller, Douglas; Lin, Henry; Beegle, Douglas; Knight, Paul

2017-04-01

USA and state nutrient management planning offers strategic guidance that strives to educate farmers and those involved in nutrient management to make wise management decisions. A goal of such programs is to manage hotspots of water quality degradation that threaten human and ecosystem health, water and food security. The guidance provided by nutrient management plans does not provide the day-to-day support necessary to make operational decisions, particularly when and where to apply nutrients over the short term. These short-term decisions on when and where to apply nutrients often make the difference between whether the nutrients impact water quality or are efficiently utilized by crops. Infiltrating rainfall events occurring shortly after broadcast nutrient applications are beneficial, given they will wash soluble nutrients into the soil where they are used by crops. Rainfall events that generate runoff shortly after nutrients are broadcast may wash off applied nutrients, and produce substantial nutrient losses from that site. We are developing a model and data based support tool for nutrient management, the Fertilizer Forecaster, which identifies the relative probability of runoff or infiltrating events in Pennsylvania (PA) landscapes in order to improve water quality. This tool will support field specific decisions by farmers and land managers on when and where to apply fertilizers and manures over 24, 48 and 72 hour periods. Our objectives are to: (1) monitor agricultural hillslopes in watersheds representing four of the five Physiographic Provinces of the Chesapeake Bay basin; (2) validate a high resolution mapping model that identifies soils prone to runoff; (3) develop an empirically based approach to relate state-of-the-art weather forecast variables to site-specific rainfall infiltration or runoff occurrence; (4) test the empirical forecasting model against alternative approaches to forecasting runoff occurrence; and (5) recruit farmers from the four watersheds to use web-based forecast maps in daily manure and fertilizer application decisions. Data from on-farm trials is being used to assess farmer fertilizer, manure, and tillage management decisions before and after use of the Fertilizer Forecaster. This data will help us understand not only the effectiveness of the tool, but also characteristics of farmers with the greatest potential to benefit from such a tool. Feedback from on-farm trials will be used to refine a final tool for field deployment. We hope that the Fertilizer Forecaster will serve as the basis for state (USA-PA), regional (Chesapeake Bay), and national changes in nutrient management planning. This Fertilizer Forecaster is an innovative management practice that is designed to enhance the services of aquatic ecosystems by improving water quality and enhance the services of terrestrial ecosystems by increasing the efficiency of nutrient use by targeted crops.

Eutrophication and Warming Boost Cyanobacterial Biomass and Microcystins.

PubMed

Lürling, Miquel; van Oosterhout, Frank; Faassen, Elisabeth

2017-02-11

Eutrophication and warming are key drivers of cyanobacterial blooms, but their combined effects on microcystin (MC) concentrations are less studied. We tested the hypothesis that warming promotes cyanobacterial abundance in a natural plankton community and that eutrophication enhances cyanobacterial biomass and MC concentrations. We incubated natural seston from a eutrophic pond under normal, high, and extreme temperatures (i.e., 20, 25, and 30 °C) with and without additional nutrients added (eutrophication) mimicking a pulse as could be expected from projected summer storms under climate change. Eutrophication increased algal- and cyanobacterial biomass by 26 and 8 times, respectively, and led to 24 times higher MC concentrations. This effect was augmented with higher temperatures leading to 45 times higher MC concentrations at 25 °C, with 11 times more cyanobacterial chlorophyll- a and 25 times more eukaryote algal chlorophyll- a . At 30 °C, MC concentrations were 42 times higher, with cyanobacterial chlorophyll- a being 17 times and eukaryote algal chlorophyll- a being 24 times higher. In contrast, warming alone did not yield more cyanobacteria or MCs, because the in situ community had already depleted the available nutrient pool. MC per potential MC producing cell declined at higher temperatures under nutrient enrichments, which was confirmed by a controlled experiment with two laboratory strains of Microcystis aeruginosa. Nevertheless, MC concentrations were much higher at the increased temperature and nutrient treatment than under warming alone due to strongly promoted biomass, lifting N-imitation and promotion of potential MC producers like Microcystis . This study exemplifies the vulnerability of eutrophic urban waters to predicted future summer climate change effects that might aggravate cyanobacterial nuisance.

Nitrogen Cycling in Seagrass Beds Dominated by Thalassia testudinum and Halodule wrightii: the Role of Nitrogen Fixation and Ammonium Oxidation in Regulating Ammonium Availability

NASA Astrophysics Data System (ADS)

Capps, R.; Caffrey, J. M.; Hester, C.

2016-02-01

Seagrass meadows provide key ecosystem services including nursery and foraging grounds, storm and erosion buffers, biodiversity enhancers and global carbon and nutrient cycling. Nitrogen concentrations are often very low in coastal waters and sediments, which may limit primary productivity. Biological nitrogen fixation is a microbial process that converts dinitrogen to ammonium, which is readily taken up by seagrasses. In the oxygenated rhizospheres, diazotrophs provide the plant with ammonium and use root exudates as an energy source. Nitrogen fixation rates and nutrient concentrations differ between seagrass species and substrate types. Thalassia testudinum has a higher biomass and is a climax species than Halodule wrightii, which is a pioneer species. Nitrogen fixation rates are relatively consistent in Thalassia testudinum dominated sediments. However, it is relatively variable in sediments occupied by Halodule wrightii. Nitrogen fixation rates are higher in bare substrate compared to areas with Thalassia testudinum, which may be due to T. testudinum's greater efficiency in nutrient retention because it is a climax species. We hypothesize that seasonal shifts in nitrogen fixation will coincide with seasonal shifts in seagrass biomass due to higher nutrient requirements during peak growth and lower requirements during senescence and dormancy. The ratio of porewater ammonium to phosphate suggests that seagrass growth may be nitrogen limited as does nitrogen demand, estimated from gross primary productivity. Significant rates of ammonium oxidation in both surface and rhizosphere sediments contribute to this imbalance. Thus, nitrogen fixation may be critical in supporting plant growth.

Electric-field-enhanced nutrient consumption in dielectric biomaterials that contain anchorage-dependent cells.

PubMed

Belfiore, Laurence A; Floren, Michael L; Belfiore, Carol J

2012-02-01

This research contribution addresses electric-field stimulation of intra-tissue mass transfer and cell proliferation in viscoelastic biomaterials. The unsteady state reaction-diffusion equation is solved according to the von Kármán-Pohlhausen integral method of boundary layer analysis when nutrient consumption and tissue regeneration occur in response to harmonic electric potential differences across a parallel-plate capacitor in a dielectric-sandwich configuration. The partial differential mass balance with diffusion and electro-kinetic consumption contains the Damköhler (Λ(2)) and Deborah (De) numbers. Zero-field and electric-field-sensitive Damköhler numbers affect nutrient boundary layer growth. Diagonal elements of the 2nd-rank diffusion tensor are enhanced in the presence of weak electric fields, in agreement with the formalism of equilibrium and nonequilibrium thermodynamics. Induced dipole polarization density within viscoelastic biomaterials is calculated via the real and imaginary components of the complex dielectric constant, according to the Debye equation, to quantify electro-kinetic stimulation. Rates of nutrient consumption under zero-field conditions are described by third-order kinetics that include local mass densities of nutrients, oxygen, and attached cells. Thinner nutrient boundary layers are stabilized at shorter dimensionless diffusion times when the zero-field intra-tissue Damköhler number increases above its initial-condition-sensitive critical value [i.e., {Λ(2)(zero-field)}(critical)≥53, see Eq. (23)], such that the biomaterial core is starved of essential ingredients required for successful proliferation. When tissue regeneration occurs above the critical electric-field-sensitive intra-tissue Damköhler number, the electro-kinetic contribution to nutrient consumption cannot be neglected. The critical electric-field-sensitive intra-tissue Damköhler number is proportional to the Deborah number. Copyright © 2011 Elsevier B.V. All rights reserved.

System and method for preparing near-surface heavy oil for extraction using microbial degradation

DOEpatents

Busche, Frederick D [Highland Village, TX; Rollins, John B [Southlake, TX; Noyes, Harold J [Golden, CO; Bush, James G [West Richland, WA

2011-04-12

A system and method for enhancing the recovery of heavy oil in an oil extraction environment by feeding nutrients to a preferred microbial species (bacteria and/or fungi). A method is described that includes the steps of: sampling and identifying microbial species that reside in the oil extraction environment; collecting fluid property data from the oil extraction environment; collecting nutrient data from the oil extraction environment; identifying a preferred microbial species from the oil extraction environment that can transform the heavy oil into a lighter oil; identifying a nutrient from the oil extraction environment that promotes a proliferation of the preferred microbial species; and introducing the nutrient into the oil extraction environment.

Regional assessments of the Nation's water quality—Improved understanding of stream nutrient sources through enhanced modeling capabilities

USGS Publications Warehouse

Preston, Stephen D.; Alexander, Richard B.; Woodside, Michael D.

2011-01-01

The U.S. Geological Survey (USGS) recently completed assessments of stream nutrients in six major regions extending over much of the conterminous United States. SPARROW (SPAtially Referenced Regressions On Watershed attributes) models were developed for each region to explain spatial patterns in monitored stream nutrient loads in relation to human activities and natural resources and processes. The model information, reported by stream reach and catchment, provides contrasting views of the spatial patterns of nutrient source contributions, including those from urban (wastewater effluent and diffuse runoff from developed land), agricultural (farm fertilizers and animal manure), and specific background sources (atmospheric nitrogen deposition, soil phosphorus, forest nitrogen fixation, and channel erosion).

Terra-Preta-Technology as an innovative system component to create circulation oriented, sustainable land use systems

NASA Astrophysics Data System (ADS)

Dotterweich, M.; Böttcher, J.; Krieger, A.

2012-04-01

This paper presents current research and application projects on innovative system solutions which are based on the implementation of a regional resource efficient material flow management as well as utilising "Terra-Preta-Technology" as an innovative system component. Terra Preta Substrate (TPS) is a recently developed substance composed of liquid and solid organic matter, including biochar, altered by acid-lactic fermentation. Based on their properties, positive effects on water and nutrient retention, soil microbiological activity, and cation-exchange capacity are expected and currently investigated by different projects. TPS further sequesters carbon and decreases NO2 emissions from fertilized soils as observed by the use of biochar. The production of TPS is based on a circulation oriented organic waste management system directly adapted to the local available inputs and desired soil amendment properties. The production of TPS is possible with simple box systems for subsistence farming but also on a much larger scale as modular industrial plants for farmers or commercial and municipal waste management companies in sizes from 500 and 50,000 m3. The Terra-Preta-Technology enhances solutions to soil conservation, soil amelioration, humic formation, reduced water consumption, long term carbon sequestration, nutrient retention, containment binding, and to biodiversity on local to a regional scale. The projects also involve research of ancient land management systems to enhance resource efficiency by means of an integrative and transdisciplinary approach.

The invasive species Alliaria petiolata (garlic mustard) increases soil nutrient availability in northern hardwood-conifer forests.

PubMed

Rodgers, Vikki L; Wolfe, Benjamin E; Werden, Leland K; Finzi, Adrien C

2008-09-01

The invasion of non-native plants can alter the diversity and activity of soil microorganisms and nutrient cycling within forests. We used field studies to analyze the impact of a successful invasive groundcover, Alliaria petiolata, on fungal diversity, soil nutrient availability, and pH in five northeastern US forests. We also used laboratory and greenhouse experiments to test three mechanisms by which A. petiolata may alter soil processes: (1) the release of volatile, cyanogenic glucosides from plant tissue; (2) the exudation of plant secondary compounds from roots; and (3) the decomposition of litter. Fungal community composition was significantly different between invaded and uninvaded soils at one site. Compared to uninvaded plots, plots invaded by A. petiolata were consistently and significantly higher in N, P, Ca and Mg availability, and soil pH. In the laboratory, the release of volatile compounds from the leaves of A. petiolata did not significantly alter soil N availability. Similarly, in the greenhouse, the colonization of native soils by A. petiolata roots did not alter soil nutrient cycling, implying that the exudation of secondary compounds has little effect on soil processes. In a leaf litter decomposition experiment, however, green rosette leaves of A. petiolata significantly increased the rate of decomposition of native tree species. The accelerated decomposition of leaf litter from native trees in the presence of A. petiolata rosette leaves shows that the death of these high-nutrient-content leaves stimulates decomposition to a greater extent than any negative effect that secondary compounds may have on the activity of the microbes decomposing the native litter. The results presented here, integrated with recent related studies, suggest that this invasive plant may change soil nutrient availability in such a way as to create a positive feedback between site occupancy and continued proliferation.

Comparison of methods for nutrient measurement in calcareous soils: Ion-exchange resin bag, capsule, membrane, and chemical extractions

USGS Publications Warehouse

Sherrod, S.K.; Belnap, J.; Miller, M.E.

2002-01-01

Four methods for measuring quantities of 12 plant-available nutrients were compared using three sandy soils in a series of three experiments. Three of the methods use different ion-exchange resin forms—bags, capsules, and membranes—and the fourth was conventional chemical extraction. The first experiment compared nutrient extraction data from a medium of sand saturated with a nutrient solution. The second and third experiments used Nakai and Sheppard series soils from Canyonlands National Park, which are relatively high in soil carbonates. The second experiment compared nutrient extraction data provided by the four methods from soils equilibrated at two temperatures, “warm” and “cold.” The third experiment extracted nutrients from the same soils in a field equilibration. Our results show that the four extraction techniques are not comparable. This conclusion is due to differences among the methods in the net quantities of nutrients extracted from equivalent soil volumes, in the proportional representation of nutrients within similar soils and treatments, in the measurement of nutrients that were added in known quantities, and even in the order of nutrients ranked by net abundance. We attribute the disparities in nutrient measurement among the different resin forms to interacting effects of the inherent differences in resin exchange capacity, differences among nutrients in their resin affinities, and possibly the relatively short equilibration time for laboratory trials. One constraint for measuring carbonate-related nutrients in high-carbonate soils is the conventional ammonium acetate extraction method, which we suspect of dissolving fine CaCO3 particles that are more abundant in Nakai series soils, resulting in erroneously high Ca2+ estimates. For study of plant-available nutrients, it is important to identify the nutrients of foremost interest and understand differences in their resin sorption dynamics to determine the most appropriate extraction method.

Gustatory and metabolic perception of nutrient stress in Drosophila.

PubMed

Linford, Nancy J; Ro, Jennifer; Chung, Brian Y; Pletcher, Scott D

2015-02-24

Sleep loss is an adaptive response to nutrient deprivation that alters behavior to maximize the chances of feeding before imminent death. Organisms must maintain systems for detecting the quality of the food source to resume healthy levels of sleep when the stress is alleviated. We determined that gustatory perception of sweetness is both necessary and sufficient to suppress starvation-induced sleep loss when animals encounter nutrient-poor food sources. We further find that blocking specific dopaminergic neurons phenocopies the absence of gustatory stimulation, suggesting a specific role for these neurons in transducing taste information to sleep centers in the brain. Finally, we show that gustatory perception is required for survival, specifically in a low nutrient environment. Overall, these results demonstrate an important role for gustatory perception when environmental food availability approaches zero and illustrate the interplay between sensory and metabolic perception of nutrient availability in regulating behavioral state.

Effects of Liming on Forage Availability and Nutrient Content in a Forest Impacted by Acid Rain

PubMed Central

Pabian, Sarah E.; Ermer, Nathan M.; Tzilkowski, Walter M.; Brittingham, Margaret C.

2012-01-01

Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer. PMID:22761890

Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

PubMed

Pabian, Sarah E; Ermer, Nathan M; Tzilkowski, Walter M; Brittingham, Margaret C

2012-01-01

Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

Facilitating nutrient aquisition of black walnut and other hardwoods at plantation establishment

Treesearch

Douglass F. Jacobs; John R. Seifert

2004-01-01

Bareroot hardwood seedlings typically undergo transplant shock immediately following planting before root systems are established. Fertilization at planting may act to minimize transplant shock by reducing nutrient stresses. However, previous work with fertilization of hardwoods at planting has generally relied on fertilizers with nutrient forms immediately available....

Short-term effects of a simulated acid rain upon the growth and nutrient relations of Pinus strobus, L.

Treesearch

Tim Wood; F. H. Bormann

1976-01-01

Acidified precipitation may affect the productivity of forests by altering the availability of plant nutrients of by affecting the ability of trees to absorb and assimilate those nutrients. In this study, the short-term effects of simulated acid rain (pH range 5.6 - 2.3) upon the growth and nutrient relations of Eastern White Pine seedlings (Pinus strobus...

Drug-nutrient interactions.

PubMed

Trovato, A; Nuhlicek, D N; Midtling, J E

1991-11-01

Drug-nutrient interactions are a commonly overlooked aspect of the prescribing practices of physicians. As more pharmaceutical agents become available, attention should be focused on interactions of drugs with foods and nutrients. Although drug-nutrient interactions are not as common as drug-drug interactions, they can have an impact on therapeutic outcome. Drugs can affect nutritional status by altering nutrient absorption, metabolism, utilization or excretion. Food, beverages and mineral or vitamin supplements can affect the absorption and effectiveness of drugs. Knowledge of drug-nutrient interactions can help reduce the incidence of these effects. Physicians should question patients about their dietary habits so that patients can be informed about possible interactions between a prescribed drug and foods and nutrients.

L-Cysteine enhances nutrient absorption via a cystathionine-β-synthase-derived H2 S pathway in rodent jejunum.

PubMed

Xiao, Ailin; Li, Jing; Liu, Tianjian; Liu, Zhuxi; Wei, Chuanfei; Xu, Xiaomeng; Li, Qin; Li, Jingxin

2016-05-01

Hydrogen sulphide (H2 S) is generated endogenously from L-cysteine (L-Cys) by the enzymes cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE). In addition, L-Cys is commonly used as a precursor in the food and pharmaceutical industries. The aim of the present study is to determine whether L-Cys regulates intestinal nutrient transport. To that end, the presence of CBS and CSE in the jejunum epithelium was assessed by immunohistochemistry, Western blotting and the methylene blue assay. In addition, in vivo L-Cys (100 mg/kg, administered immediately after the glucose load) significantly increased blood glucose levels 30 min after the oral administration of glucose to mice. This effect of L-Cys was completely blocked by amino-oxyacetic acid (AOA; 50 mg/kg; administered at the same time as L-Cys) an inhibitor of CBS. Measurements of the short-circuit current (Isc) in the rat jejunum epithelium revealed that L-Cys (1 mmol/L; 6 min before the administration of L-alanine) enhances Na(+)-coupled L-alanine or glucose transport, and that this effect is inhibited by AOA (1 mmol/L;10 min before the administration of L-Cys), but not D,L-propargylglycine (PAG;1 mmol/L; 10 min before the administration of L-Cys), a CSE inhibitor. Notably, L-Cys-evoked enhancement of nutrient transport was alleviated by glibenclamide (Gli;0.1 mmol/L; 10 min before the administration of L-Cys), a K(+) channel blocker. Together, the data indicate that L-Cys enhances jejunal nutrient transport, suggesting a new approach to future treatment of nutrition-related maladies, including a range of serious health consequences linked to undernutrition. © 2016 John Wiley & Sons Australia, Ltd.

Are freshwater diversion projects in Louisiana wetlands doing more harm than good?

NASA Astrophysics Data System (ADS)

Schulz, C. J.; Childers, G. W.

2009-12-01

Several freshwater diversion projects are online and many more are proposed, drastically altering the hydrology and nutrient flux in Louisiana wetlands. The intention of these massive projects is to prevent saltwater intrusion and provide sediments and nutrients to combat coastal erosion and subsidence. A proposed mechanism that such diversions decrease land loss is through the increase in vegetative biomass accumulation, leading to net gains in organic sediments. Although freshwater and nutrients can enhance primary production, it is unclear what impact these waters will have on existing sediment organic reservoirs. There are a limited, but growing number of studies suggesting that nutrient additions to wetland systems can lead to enhanced soil decomposition; thus, freshwater diversion projects may actually enhance wetland deterioration. A wetland restoration project delivering five million gallons per day of treated domestic effluent to the Joyce Wildlife Management Area (JWMA) marsh began in 2006. The treated effluent is similar to Mississippi River water with respect to alkalinity and reactive nitrogen concentrations. Sediment carbon and nitrogen content was monitored pre and post restoration project commencement and decreased significantly over a two year period from 2006 to 2008. The change in water chemistry (alkalinity/pH and reactive nitrogen) was expected to have an impact on microbial activities in these sediments. The microbial community composition of methanogens and archaeal ammonia oxidizers (as monitored by mcrA and amoA gene clone libraries, respectively) also shifted during this time period. Microcosm experiments using relatively un-impacted JWMA sediments with cellulose amendments showed increased methane production (i.e. enhanced organic matter / plant matter decomposition) corresponding to increasing alkalinity. Possible mechanisms accounting for these observations can be explained by thermodynamic constraints in anaerobic degradation pathways.

Innovations in Food Chemistry and Processing to Enhance the Nutrient Profile of the White Potato in All Forms12

PubMed Central

Decker, Eric A.; Ferruzzi, Mario G.

2013-01-01

Potatoes can be an important part of a balanced diet because they are an excellent source of many nutrients, including nutrients that are commonly underconsumed (dietary fiber and potassium). Despite the existence of many positive nutrients in potatoes, the popular press has recently aligned potatoes, and particularly fried potatoes, with an unhealthy diet. This article examines the nutritional content of potatoes and how these nutrients are affected by cooking and other food-processing operations. In addition, it examines how the nutritional content of potatoes is altered by cooking methods and how fried potatoes can have wide variations in fat content depending on the cooking method. Finally, the potential of new food-processing technologies to improve the nutritional content of cooked potatoes is evaluated. PMID:23674803

Potassium fertigation in highbush blueberry increases availability of K and other nutrients in the root zone

USDA-ARS?s Scientific Manuscript database

Fertigation with nitrogen (N) increases growth and production relative to granular N applications in blueberry, but little information is available on whether there is any benefit to fertigating with other nutrients. The plants were grown on raised beds and irrigated using two lines of drip tubing p...

NGEE Arctic Plant Traits: Soil Nutrient Availability, Kougarok Road Mile Marker 64, Seward Peninsula, Alaska, beginning 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verity Salmon; Colleen Iversen; Amy Breen

Soil nutrient availability at all vegetation plots was measured using anion and cation binding resins deployed to vegetation plots at the Kougarok hillslope site located at Kougarok Road Marker 64. Concentrations of ammonia, nitrate, and phosphate in resin extract solutions were determined in the lab.

Natural and anthropogenic drivers of calcium depletion in a northern forest during the last millennium.

PubMed

Leys, Bérangère A; Likens, Gene E; Johnson, Chris E; Craine, Joseph M; Lacroix, Brice; McLauchlan, Kendra K

2016-06-21

The pace and degree of nutrient limitation are among the most critical uncertainties in predicting terrestrial ecosystem responses to global change. In the northeastern United States, forest growth has recently declined along with decreased soil calcium (Ca) availability, suggesting that acid rain has depleted soil Ca to the point where it may be a limiting nutrient. However, it is unknown whether the past 60 y of changes in Ca availability are strictly anthropogenic or partly a natural consequence of long-term ecosystem development. Here, we report a high-resolution millennial-scale record of Ca and 16 other elements from the sediments of Mirror Lake, a 15-ha lake in the White Mountains of New Hampshire surrounded by northern hardwood forest. We found that sedimentary Ca concentrations had been declining steadily for 900 y before regional Euro-American settlement. This Ca decline was not a result of serial episodic disturbances but instead the gradual weathering of soils and soil Ca availability. As Ca availability was declining, nitrogen availability concurrently was increasing. These data indicate that nutrient availability on base-poor, parent materials is sensitive to acidifying processes on millennial timescales. Forest harvesting and acid rain in the postsettlement period mobilized significant amounts of Ca from watershed soils, but these effects were exacerbated by the long-term pattern. Shifting nutrient limitation can potentially occur within 10,000 y of ecosystem development, which alters our assessments of the speed and trajectory of nutrient limitation in forests, and could require reformulation of global models of forest productivity.

Natural and anthropogenic drivers of calcium depletion in a northern forest during the last millennium

PubMed Central

Leys, Bérangère A.; Likens, Gene E.; Craine, Joseph M.; Lacroix, Brice; McLauchlan, Kendra K.

2016-01-01

The pace and degree of nutrient limitation are among the most critical uncertainties in predicting terrestrial ecosystem responses to global change. In the northeastern United States, forest growth has recently declined along with decreased soil calcium (Ca) availability, suggesting that acid rain has depleted soil Ca to the point where it may be a limiting nutrient. However, it is unknown whether the past 60 y of changes in Ca availability are strictly anthropogenic or partly a natural consequence of long-term ecosystem development. Here, we report a high-resolution millennial-scale record of Ca and 16 other elements from the sediments of Mirror Lake, a 15-ha lake in the White Mountains of New Hampshire surrounded by northern hardwood forest. We found that sedimentary Ca concentrations had been declining steadily for 900 y before regional Euro-American settlement. This Ca decline was not a result of serial episodic disturbances but instead the gradual weathering of soils and soil Ca availability. As Ca availability was declining, nitrogen availability concurrently was increasing. These data indicate that nutrient availability on base-poor, parent materials is sensitive to acidifying processes on millennial timescales. Forest harvesting and acid rain in the postsettlement period mobilized significant amounts of Ca from watershed soils, but these effects were exacerbated by the long-term pattern. Shifting nutrient limitation can potentially occur within 10,000 y of ecosystem development, which alters our assessments of the speed and trajectory of nutrient limitation in forests, and could require reformulation of global models of forest productivity. PMID:27298361

Evidence for circulatory benefits of resveratrol in humans.

PubMed

Wong, Rachel H X; Coates, Alison M; Buckley, Jonathan D; Howe, Peter R C

2013-07-01

Impairments of endothelial function, which can be assessed noninvasively by flow-mediated dilation (FMD) of the brachial artery, contribute to the development of cardiovascular disease. Associations between FMD and cognition suggest a vascular component in the loss of cognitive function. Certain vasoactive nutrients that have been shown to improve FMD may also have the potential to enhance cerebral perfusion and cognition. Preclinical studies show that trans-resveratrol can enhance nitric oxide bioavailability, thereby increasing endothelium-dependent vasodilation. We have now shown that acute administration of resveratrol elicits dose-dependent increases of FMD with greater potency than other vasoactive nutrients and that this benefit is sustained following regular consumption. We describe the potential implications of this vasodilator benefit of resveratrol and its role in enhancing cerebrovascular and cognitive functions. © 2013 New York Academy of Sciences.

The role of Juncus effusus litter quality and nutrient availability on organic matter decomposition in restored cutover bogs

NASA Astrophysics Data System (ADS)

Agethen, Svenja; Knorr, Klaus-Holger

2017-04-01

More than 90% of peatlands in Europe are degraded by drainage and subsequent land use. However, beneficial effects of functioning peatlands, most of all carbon storage, have long been recognized but remain difficult to recover. Fragmentation and a surrounding of intensively used agricultural catchments with excess nutrients in air and waters further affects the recovery of sites. Under such conditions, highly competitive species such as Juncus effusus colonize restored peatlands instead of peat forming Sphagnum. While the specific stoichiometry and chemical composition makes Sphagnum litter recalcitrant in decomposition and hence, effective in carbon sequestration, we know little about dynamics involving Juncus, although this species provides organic matter in high quantity and of rather labile quality. To better understand decomposition in context of litter quality and nutrient availability, we incubated different peat types for 70 days; I) recent, II) weakly degraded fossil, and III) earthyfied nutrient rich fossil peat, amended with two 13C pulse-labelled Juncus litter types (excessively fertilized "F", and nutrient poor "NF" plants grown for three years watered with MilliQ only), respectively. We determined anaerobic decomposition rates, compared potential rates extrapolated from pure materials with measured rates of the mixtures, and tracked the 13C in the solid, liquid, and gaseous phase. To characterize the biogeochemical conditions, inorganic and organic electron acceptors, hydrogen and organic acids, and total enzyme activity were monitored. For characterization of dissolved organic matter we used UV-Vis and fluorescence spectroscopy (parallel factor analysis), and for solid organic matter elemental analysis and FTIR spectroscopy. There were two main structural differences between litter types: "F" litter and its leachates contained more proteinaceous components, the C/N ratio was 20 in contrast to 60 of the "NF" litter. However, humic components and aromaticity were higher in "F" litter. Generally, decomposition rates of litter were 5-30 times higher than of peat. Rates in batches amended with "F" were lower compared to "NF" for the respective peat, opposing typically reported observations. Nevertheless, the 13C label suggested that in case of peat I and III preferably the litter was decomposed, decomposition of peat II was apparently stimulated when "NF" was added, albeit this litter was poor in nutrients. Multiple linear regression identified specific absorption at 254 nm (SUVA), a measure of aromaticity representative for an array of inter-correlating spectroscopic features, and enzyme activity as most important predictors for C-mineralization rates. These two parameters explained 88% of the variance. Although enzyme activity and SUVA did not correlate in the mixed assays, this was the case for the pure materials (R2=0.95), suggesting an inhibitory effect of aromatic components on enzyme activity. This study confirms that generally litter quality is a major control for mineralization and hence, carbon storage in peatlands. Interestingly, in the case of Juncus effusus, high nutrient availability in peat and litter did not lead to enhanced degradation of the litter itself or priming of decomposition of the surrounding peat. Furthermore, the results underline the substantial contribution of Juncus biomass to C-cycling and potentially high C-emissions in restored peatlands.

Marine-derived nutrients, bioturbation, and ecosystem metabolism: reconsidering the role of salmon in streams.

PubMed

Holtgrieve, Gordon W; Schindler, Daniel E

2011-02-01

In coastal areas of the North Pacific Ocean, annual returns of spawning salmon provide a substantial influx of nutrients and organic matter to streams and are generally believed to enhance the productivity of recipient ecosystems. Loss of this subsidy from areas with diminished salmon runs has been hypothesized to limit ecosystem productivity in juvenile salmon rearing habitats (lakes and streams), thereby reinforcing population declines. Using five to seven years of data from an Alaskan stream supporting moderate salmon densities, we show that salmon predictably increased stream water nutrient concentrations, which were on average 190% (nitrogen) and 390% (phosphorus) pre-salmon values, and that primary producers incorporated some of these nutrients into tissues. However, benthic algal biomass declined by an order of magnitude despite increased nutrients. We also measured changes in stream ecosystem metabolic properties, including gross primary productivity (GPP) and ecosystem respiration (ER), from three salmon streams by analyzing diel measurements of oxygen concentrations and stable isotopic ratios (delta O-O2) within a Bayesian statistical model of oxygen dynamics. Our results do not support a shift toward higher primary productivity with the return of salmon, as is expected from a nutrient fertilization mechanism. Rather, net ecosystem metabolism switched from approximately net autotrophic (GPP > or = ER) to a strongly net heterotrophic state (GPP < ER) in response to bioturbation of benthic habitats by salmon. Following the seasonal arrival of salmon, GPP declined to <12% of pre-salmon rates, while ER increased by over threefold. Metabolism by live salmon could not account for the observed increase in ER early in the salmon run, suggesting salmon nutrients and disturbance enhanced in situ heterotrophic respiration. Salmon also changed the physical properties of the stream, increasing air-water gas exchange by nearly 10-fold during peak spawning. We suggest that management efforts to restore salmon ecosystems should consider effects on ecosystem metabolic properties and how salmon disturbance affects the incorporation of marine-derived nutrients into food webs.

The emerging role of mTORC1 signaling in placental nutrient-sensing.

PubMed

Jansson, T; Aye, I L M H; Goberdhan, D C I

2012-11-01

Nutrient-sensing signaling pathways regulate cell metabolism and growth in response to altered nutrient levels and growth factor signaling. Because trophoblast cell metabolism and associated signaling influence fetal nutrient availability, trophoblast nutrient sensors may have a unique role in regulating fetal growth. We review data in support of a role for mammalian target of rapamycin complex 1 (mTORC1) in placental nutrient-sensing. Placental insulin/IGF-I signaling and fetal levels of oxygen, glucose and amino acids (AAs) are altered in pregnancy complications such as intrauterine growth restriction, and all these factors are well-established upstream regulators of mTORC1. Furthermore, mTORC1 is a positive regulator of placental AA transporters, suggesting that trophoblast mTORC1 modulates AA transfer across the placenta. In addition, placental mTORC1 signaling is also known to be modulated in pregnancy complications associated with altered fetal growth and in animal models in which maternal nutrient availability has been altered experimentally. Recently, significant progress has been made in identifying the molecular mechanisms by which mTORC1 senses AAs, a process requiring shuttling of mTOR to late endosomal and lysosomal compartments (LELs). We recently identified members of the proton-assisted amino acid transporter (PAT/SLC36) family as critical components of the AA-sensing system or 'nutrisome' that regulates mTORC1 on LEL membranes, placing AA transporters and their subcellular regulation both upstream and downstream of mTORC1-driven processes. We propose a model in which placental mTORC1 signaling constitutes a critical link between maternal nutrient availability and fetal growth, thereby influencing the long-term health of the fetus. Copyright © 2012 Elsevier Ltd. All rights reserved.

Food Web Architecture and Basal Resources Interact to Determine Biomass and Stoichiometric Cascades along a Benthic Food Web

PubMed Central

Guariento, Rafael D.; Carneiro, Luciana S.; Caliman, Adriano; Leal, João J. F.; Bozelli, Reinaldo L.; Esteves, Francisco A.

2011-01-01

Understanding the effects of predators and resources on primary producers has been a major focus of interest in ecology. Within this context, the trophic cascade concept especially concerning the pelagic zone of lakes has been the focus of the majority of these studies. However, littoral food webs could be especially interesting because base trophic levels may be strongly regulated by consumers and prone to be light limited. In this study, the availability of nutrients and light and the presence of an omnivorous fish (Hyphessobrycon bifasciatus) were manipulated in enclosures placed in a humic coastal lagoon (Cabiúnas Lagoon, Macaé – RJ) to evaluate the individual and interactive effects of resource availability (nutrients and light) and food web configuration on the biomass and stoichiometry of periphyton and benthic grazers. Our findings suggest that light and nutrients interact to determine periphyton biomass and stoichiometry, which propagates to the consumer level. We observed a positive effect of the availability of nutrients on periphytic biomass and grazers' biomass, as well as a reduction of periphytic C∶N∶P ratios and an increase of grazers' N and P content. Low light availability constrained the propagation of nutrient effects on periphyton biomass and induced higher periphytic C∶N∶P ratios. The effects of fish presence strongly interacted with resource availability. In general, a positive effect of fish presence was observed for the total biomass of periphyton and grazer's biomass, especially with high resource availability, but the opposite was found for periphytic autotrophic biomass. Fish also had a significant effect on periphyton stoichiometry, but no effect was observed on grazers' stoichiometric ratios. In summary, we observed that the indirect effect of fish predation on periphyton biomass might be dependent on multiple resources and periphyton nutrient stoichiometric variation can affect consumers' stoichiometry. PMID:21789234

Identification of Candidate Transcriptional Regulators of Epidermal Transfer Cell Development in Vicia faba Cotyledons

PubMed Central

Arun-Chinnappa, Kiruba S.; McCurdy, David W.

2016-01-01

Transfer cells (TCs) are anatomically-specialized cells formed at apoplasmic-symplasmic bottlenecks in nutrient transport pathways in plants. TCs form invaginated wall ingrowths which provide a scaffold to amplify plasma membrane surface area and thus increase the density of nutrient transporters required to achieve enhanced nutrient flow across these bottlenecks. Despite their importance to nutrient transport in plants, little is known of the transcriptional regulation of wall ingrowth formation. Here, we used RNA-Seq to identify transcription factors putatively involved in regulating epidermal TC development in cotyledons of Vicia faba. Comparing cotyledons cultured for 0, 3, 9, and 24 h to induce trans-differentiation of epidermal TCs identified 43 transcription factors that showed either epidermal-specific or epidermal–enhanced expression, and 10 that showed epidermal-specific down regulation. Members of the WRKY and ethylene-responsive families were prominent in the cohort of transcription factors showing epidermal-specific or epidermal–enhanced expression, consistent with the initiation of TC development often representing a response to stress. Members of the MYB family were also prominent in these categories, including orthologs of MYB genes involved in localized secondary wall deposition in Arabidopsis thaliana. Among the group of transcription factors showing down regulation were various homeobox genes and members of the MADs-box and zinc-finger families of poorly defined functions. Collectively, this study identified several transcription factors showing expression characteristics and orthologous functions that indicate likely participation in transcriptional regulation of epidermal TC development in V. faba cotyledons. PMID:27252730

The Consequences of Precipitation Seasonality for Mediterranean-Ecosystem Vegetation of South Africa.

PubMed

Cramer, Michael D; Hoffman, M Timm

2015-01-01

Globally, mediterranean-climate ecosystem vegetation has converged on an evergreen, sclerophyllous and shrubby growth form. The particular aspects of mediterranean-climate regions that contribute to this convergence include summer droughts and relatively nutrient-poor soils. We hypothesised that winter-precipitation implies stressful summer droughts and leaches soils due to greater water availability (i.e. balance between precipitation and potential evapotranspiration; P-PET) during cold periods. We conducted a comparative analysis of normalised difference vegetation indices (NDVI) and edaphic and climate properties across the biomes of South Africa. NDVI was strongly correlated with both precipitation and P-PET (r2 = 0.8). There was no evidence, however, that winter-precipitation reduces NDVI in comparison to similar amounts of summer-precipitation. Base saturation (BS), a measure of soil leaching was, however, negatively related to P-PET (r2 = 0.64). This led to an interaction between P-PET and BS in determining NDVI, indicating the existence of a trade-off between water availability and soil nutrients that enables NDVI to increase with precipitation, despite negative consequences for soil nutrient availability. The mechanism of this trade-off is suggested to be that water increases nutrient accessibility. This implies that along with nutrient-depauperate geologies and long periods of time since glaciation, the winter-precipitation may have contributed to the highly leached status of the soils. Since many of the ecophysiological characteristics of mediterranean-ecosystem flora are associated with low nutrient availabilities (e.g. evergreen foliage, sclerophylly, cluster roots), we conclude that mediterranean-climates promote convergence of growth-forms in these regions through high leaching capacity.

The Consequences of Precipitation Seasonality for Mediterranean-Ecosystem Vegetation of South Africa

PubMed Central

2015-01-01

Globally, mediterranean-climate ecosystem vegetation has converged on an evergreen, sclerophyllous and shrubby growth form. The particular aspects of mediterranean-climate regions that contribute to this convergence include summer droughts and relatively nutrient-poor soils. We hypothesised that winter-precipitation implies stressful summer droughts and leaches soils due to greater water availability (i.e. balance between precipitation and potential evapotranspiration; P–PET) during cold periods. We conducted a comparative analysis of normalised difference vegetation indices (NDVI) and edaphic and climate properties across the biomes of South Africa. NDVI was strongly correlated with both precipitation and P–PET (r2 = 0.8). There was no evidence, however, that winter-precipitation reduces NDVI in comparison to similar amounts of summer-precipitation. Base saturation (BS), a measure of soil leaching was, however, negatively related to P–PET (r2 = 0.64). This led to an interaction between P–PET and BS in determining NDVI, indicating the existence of a trade-off between water availability and soil nutrients that enables NDVI to increase with precipitation, despite negative consequences for soil nutrient availability. The mechanism of this trade-off is suggested to be that water increases nutrient accessibility. This implies that along with nutrient-depauperate geologies and long periods of time since glaciation, the winter-precipitation may have contributed to the highly leached status of the soils. Since many of the ecophysiological characteristics of mediterranean-ecosystem flora are associated with low nutrient availabilities (e.g. evergreen foliage, sclerophylly, cluster roots), we conclude that mediterranean-climates promote convergence of growth-forms in these regions through high leaching capacity. PMID:26650081

Light Is More Important Than Nutrient Ratios of Fertilization for Cymodocea nodosa Seedling Development.

PubMed

Alexandre, Ana; Silva, João; Santos, Rui

2018-01-01

Restoration of seagrass beds through seedlings is an alternative to the transplantation of adult plants that reduces the impact over donor areas and increases the genetic variability of restored meadows. To improve the use of Cymodocea nodosa seedlings, obtained from seeds germinated in vitro , in restoration programs, we investigated the ammonium and phosphate uptake rates of seedlings, and the synergistic effects of light levels (20 and 200 μmol quanta m -2 s -1 ) and different nitrogen to phosphorus molar ratios (40 μM N:10 μM P, 25 μM N:25 μM P, and 10 μM N:40 μM P) on the photosynthetic activity and growth of seedlings. The nutrient content of seedlings was also compared to the seed nutrient reserves to assess the relative importance of external nutrient uptake for seedling development. Eighty two percent of the seeds germinated after 48 days at a mean rate of 1.5 seeds per day. All seedlings under all treatments survived and grew during the 4 weeks of the experiment. Seedlings of C. nodosa acquired ammonium and phosphate from the incubation media while still attached to the seed, at rates of about twice of adult plants. The relevance of external nutrient uptake was further highlighted by the observation that seedlings' tissues were richer in nitrogen and phosphorus than non-germinated seeds. The uptake of ammonium followed saturation kinetics with a half saturation constant of 32 μM whereas the uptake of phosphate increased linearly with nutrient concentration within the range tested (5 - 100 μM). Light was more important than the nutrient ratio of fertilization for the successful development of the young seedlings. The seedlings' photosynthetic and growth rates were about 20% higher in the high light treatment, whereas different nitrogen to phosphorus ratios did not significantly affect growth. The photosynthetic responses of the seedlings to changes in the light level and their capacity to use external nutrient sources showed that seedlings of C. nodosa have the ability to rapidly acclimate to the surrounding light and nutrient environment while still attached to the seeds. C. nodosa seedlings experiencing fertilization under low light levels showed slightly enhanced growth if nourished with a balanced formulation, whereas a slight increase in growth was also observed with unbalanced formulations under a higher light level. Our results highlight the importance of high light availability at the seedling restoration sites.

Database of nutrient digestibility’s of traditional and novel feed ingredients for trout and hybrid striped bass

USDA-ARS?s Scientific Manuscript database

The determination of nutrient digestibility’s in specific ingredients and diets for fish has been an area of active research for decades. The Apparent Digestibility Coefficients (ADC), the percentage of nutrients in an ingredient that are available to the fish, is information needed by researchers,...

Wastewater and Sludge Nutrient Utilization in Forest Ecosystems

Treesearch

D.G. Brockway; D.H. Urie; P.V. Nguyen; J.B. Hart

1986-01-01

Although forest ecosystems have evolved efficient mechanisms to assimilate and retain modest levels of annual geochemical input, their productivity is frequently limited by low levels of available nutrients. A review of research studies conducted in the major U.S. forest regions indicates that the nutrients and organic matter in wastewater and sludge representa...

Nutrient Supplying Potential of Different Spent Mushroom Substrate Preparations as Soil Amendment in a Potting Media

NASA Astrophysics Data System (ADS)

Ultra, VU, Jr.; Ong Sotto, JME; Punzalan, MR

2018-03-01

A three consecutive cropping experiment was conducted to evaluate the nutrient supplying potential of different preparations of the spent mushroom substrate as an amendment of growing media for potted plants using pechay as test plant. There are 12 treatment combinations consisted 4 types of growing media containing soil alone and mixtures of soil with fresh SMS (FSMS), weathered SMS (WSMS) and carbonized SMS (CSMS) in combination with 0%, 50% or 100% recommended rate (RR) of nitrogen fertilizer. Succeeding two trials were conducted on the same pots and treatment assignments. The high yield of pechay during the first and second crop was observed on WSMS and CSMS treatments FSMS media produced high yields only during the 3rd crop. Yield was increased by N fertilizer in WSMS and CSMS treatments but not in FSMS. The growth differences is attributed to differences in available nutrients and C/N ratio between treatments. WSMS and CSMS increased the available N while FSMS immobilized N and other nutrients indicting that weathered SMS and carbonized SMS are more suitable as a component of potting media or as soil amendments without detrimental effect on immobilization and availability of nutrients.

Overnutrition, mTOR signaling, and cardiovascular diseases

PubMed Central

Jia, Guanghong; Aroor, Annayya R.; Martinez-Lemus, Luis A.

2014-01-01

The prevalence of obesity and associated medical disorders has increased dramatically in the United States and throughout much of the world in the past decade. Obesity, induced by excess intake of carbohydrates and fats, is a major cause of Type 2 diabetes, hypertension, and the cardiorenal metabolic syndrome. There is emerging evidence that excessive nutrient intake promotes signaling through the mammalian target of rapamycin (mTOR), which, in turn, may lead to alterations of cellular metabolic signaling leading to insulin resistance and obesity-related diseases, such as diabetes, cardiovascular and kidney disease, as well as cancer. While the pivotal role of mTOR signaling in regulating metabolic stress, autophagy, and adaptive immune responses has received increasing attention, there remain many gaps in our knowledge regarding this important nutrient sensor. For example, the precise cellular signaling mechanisms linking excessive nutrient intake and enhanced mTOR signaling with increased cardiovascular and kidney disease, as well as cancer, are not well understood. In this review, we focus on the effects that the interaction between excess intake of nutrients and enhanced mTOR signaling have on the promotion of obesity-associated diseases and potential therapeutic strategies involving targeting mTOR signaling. PMID:25253086

Enhancing tolerance of rice (Oryza sativa) to simulated acid rain by exogenous abscisic acid.

PubMed

Wu, Xi; Liang, Chanjuan

2017-02-01

Abscisic acid (ABA) regulates much important plant physiological and biochemical processes and induces tolerance to different stresses. Here, we studied the regulation of exogenous ABA on adaptation of rice seedlings to simulated acid rain (SAR) stress by measuring biomass dry weight, stomatal conductance, net photosynthesis rate, nutrient elements, and endogenous hormones. The application of 10 μM ABA alleviated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and decreases in contents of nutrient (K, Mg, N, and P) and hormone (auxin, gibberellins, and zeatin). Moreover, 10 μM ABA could stimulate the Ca content as signaling molecules under SAR stress. Contrarily, the application of 100 μM ABA aggravated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and contents of nutrient and hormone. The results got after a 5-day recovery (without SAR) show that exogenous 10 μM ABA can promote self-restoration process in rice whereas 100 μM ABA hindered the restoration by increasing deficiency of nutrients and disturbing the balance of hormones. These results confirmed that exogenous ABA at proper concentration could enhance the tolerance of rice to SAR stress.

Iron and protein biofortification of cassava: lessons learned.

PubMed

Leyva-Guerrero, Elisa; Narayanan, Narayanan N; Ihemere, Uzoma; Sayre, Richard T

2012-04-01

Over two hundred and fifty million Africans rely on the starchy root crop cassava (Manihot esculenta) as their primary source of calories. Cassava roots, however, have the lowest protein:energy ratio of all the world's major staple crops. Furthermore, a typical cassava-based diet provides less than 10-20% of the required amounts of iron, zinc, vitamin A and vitamin E. The BioCassava Plus program employed modern biotechnologies to improve the health of Africans through development and delivery of novel cassava germplasm with increased nutrient levels. Here we describe the development of molecular strategies and their outcomes to meet minimum daily allowances for protein and iron in cassava based diets. We demonstrate that cyanogens play a central role in cassava nitrogen metabolism and that strategies employed to increase root protein levels result in reduced cyanogen levels in roots. We also demonstrate that enhancing root iron uptake has an impact on the expression of genes that regulate iron homeostasis in multiple tissues. These observations demonstrate the complex metabolic interactions involved in enhancing targeted nutrient levels in plants and identify potential new strategies for further enhancing nutrient levels in cassava. Published by Elsevier Ltd.

Phytohormonal basis for the plant growth promoting action of naturally occurring biostimulators.

PubMed

Kurepin, Leonid V; Zaman, Mohammad; Pharis, Richard P

2014-07-01

There is increasing interest in the use of naturally occurring 'biostimulators' for enhancing the growth of agricultural and horticultural crops. Bacteria, fungi and protozoa, as well as marine algae-based seaweed extracts, can produce or contain biostimulators. The activity of biostimulators to promote plant growth is often attributed to their ability to directly or indirectly provide mineral nutrients (mostly N, but also P, S and other macro- and micro-nutrients) to plants. Alternatively, biostimulators are postulated to increase the plant's ability to assimilate these mineral nutrients, often in return for photo-assimilates (as occurs with certain bacteria and fungi associations). Although optimal growth of plants depends on the availability of adequate mineral nutritients, that growth (and also development, including reproduction) is also regulated by plant hormones (phytohormones), including gibberellins, auxins and cytokinins. This review describes and discusses the evidence that the presence or application of biostimulators also increases plant growth directly via phytohormone action and also influences the plant's ability to control its own hormone biosynthesis and homeostasis. Finally, it discusses the need for a better understanding of the role(s) that are played by the naturally occurring biostimulators associated with the plant in the crop field. It is suggested that better understanding will allow for optimal crop yield returns, since disruptions of phytohormone homeostasis in plant organs and tissues can yield either beneficial or sub-optimal outcomes. © 2013 Society of Chemical Industry.

Development of natural treatment system consisting of black soil and Kentucky bluegrass for the post-treatment of anaerobically digested strong wastewater.

PubMed

Chen, Xiaochen; Fukushi, Kensuke

2016-03-01

To develop a sound post-treatment process for anaerobically-digested strong wastewater, a novel natural treatment system comprising two units is put forward. The first unit, a trickling filter, provides for further reduction of biochemical oxygen demand and adjustable nitrification. The subsequent soil-plant unit aims at removing and recovering the nutrients nitrogen (N), phosphorus (P) and potassium (K). As a lab-scale feasibility study, a soil column test was conducted, in which black soil and valuable Kentucky bluegrass were integrated to treat artificial nutrient-enriched wastewater. After a long-term operation, the nitrification function was well established in the top layers, despite the need for an improved denitrification process prior to discharge. P and K were retained by the soil through distinct mechanisms. Since they either partially or totally remained in plant-available forms in the soil, indirect nutrient reuse could be achieved. As for Kentucky bluegrass, it displayed better growth status when receiving wastewater, with direct recovery of 8%, 6% and 14% of input N, P and K, respectively. Furthermore, the indispensable role of Kentucky bluegrass for better treatment performance was proved, as it enhanced the cell-specific nitrification potential of the soil nitrifying microorganisms inhabiting the rhizosphere. After further upgrade, the proposed system is expected to become a new solution for strong wastewater pollution. Copyright © 2015. Published by Elsevier B.V.

Carry over effects of nutrient addition on the recovery of an invasive seaweed from the winter die-back.

PubMed

Uyà, Marc; Maggi, Elena; Mori, Giovanna; Nuccio, Caterina; Gribben, Paul E; Bulleri, Fabio

2017-05-01

Nutrient enrichment of coastal waters can enhance the invasibility and regrowth of non-native species. The invasive alga Caulerpa cylindracea has two distinct phases: a well-studied fast-growing summer phase, and a winter latent phase. To investigate the effects of nutrient enrichment on the regrowth of the seaweed after the winter resting-phase, a manipulative experiment was carried out in intertidal rockpools in the North-western Mediterranean. Nutrients were supplied under different temporal regimes: press (constant release from January to May), winter pulse (January to March) and spring pulse (March to May). Independently from the temporal characteristics of their addition, nutrients accelerated the re-growth of C. cylindracea after the winter die-back, resulting in increased percentage covers at the peak of the growing season. Nutrient addition did not influence the number and length of fronds and the biomass. Native components of the algal community did not respond to nutrient additions. Our results show that nutrient supply can favour the spread of C. cylindracea even when occurring at a time of the year at which the seaweed is not actively growing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dynamics of Inorganic Nutrients in Intertidal Sediments: Porewater, Exchangeable, and Intracellular Pools

PubMed Central

Garcia-Robledo, Emilio; Bohorquez, Julio; Corzo, Alfonso; Jimenez-Arias, Juan L.; Papaspyrou, Sokratis

2016-01-01

The study of inorganic nutrients dynamics in shallow sediments usually focuses on two main pools: porewater (PW) nutrients and exchangeable (EX) ammonium and phosphate. Recently, it has been found that microphytobenthos (MPB) and other microorganisms can accumulate large amounts of nutrients intracellularly (IC), highlighting the biogeochemical importance of this nutrient pool. Storing nutrients could support the growth of autotrophs when nutrients are not available, and could also provide alternative electron acceptors for dissimilatory processes such as nitrate reduction. Here, we studied the magnitude and relative importance of these three nutrient pools (PW, IC, and EX) and their relation to chlorophylls (used as a proxy for MPB abundance) and organic matter (OM) contents in an intertidal mudflat of Cadiz Bay (Spain). MPB was localized in the first 4 mm of the sediment and showed a clear seasonal pattern; highest chlorophylls content was found during autumn and lowest during spring-summer. The temporal and spatial distribution of nutrients pools and MPB were largely correlated. Ammonium was higher in the IC and EX fractions, representing on average 59 and 37% of the total ammonium pool, respectively. Similarly, phosphate in the IC and EX fractions accounted on average for 40 and 31% of the total phosphate pool, respectively. Nitrate in the PW was low, suggesting low nitrification activity and rapid consumption. Nitrate accumulated in the IC pool during periods of moderate MPB abundance, being up to 66% of the total nitrate pool, whereas it decreased when chlorophyll concentration peaked likely due to a high nitrogen demand. EX-Nitrate accounted for the largest fraction of total sediment nitrate, 66% on average. The distribution of EX-Nitrate was significantly correlated with chlorophyll and OM, which probably indicates a relation of this pool to an increased availability of sites for ionic adsorption. This EX-Nitrate pool could represent an alternative nitrate source with significant concentrations available to the microbial community, deeper in the sediment below the oxic layer. PMID:27303370

Nutrient availability affects floral scent much less than other floral and vegetative traits in Lithophragma bolanderi.

PubMed

Friberg, Magne; Waters, Mia T; Thompson, John N

2017-09-01

Many plant-pollinator interactions are mediated by floral scents that can vary among species, among populations within species and even among individuals within populations. This variation could be innate and unaffected by the environment, but, because many floral volatiles have amino-acid precursors, scent variation also could be affected by differences in nutrient availability among environments. In plants that have coevolved with specific pollinators, natural selection is likely to favour low phenotypic plasticity in floral scent even under different conditions of nutrient availability if particular scents or scent combinations are important for attracting local pollinators. Clonal pairs of multiple seed-families of two Lithophragma bolanderi (Saxifragaceae) populations were subjected to a high and a low nutrient treatment. These plants are pollinated primarily by host-specific Greya moths. It was evaluated how nutrient treatment affected variation in floral scent relative to other vegetative and reproductive traits. Floral scent strength (the per-flower emission rate) and composition were unaffected by nutrient treatment, but low-nutrient plants produced fewer and lighter leaves, fewer scapes and fewer flowers than high-nutrient plants. The results held in both populations, which differed greatly in the number and composition of floral scents produced. The results reveal a strong genetic component both to scent composition and emission level, and partly contrasts with the only previous study that has assessed the susceptibility of floral volatile signals to variation in the abundance of nutrients. These results, and the tight coevolutionary relationship between Lithophragma plants and their specialized Greya moth pollinators, indicate that reproductive traits important to coevolving interactions, such as the floral scent of L. bolanderi, may be locally specialized and more canalized than other traits important for plant fitness. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Dynamics of Inorganic Nutrients in Intertidal Sediments: Porewater, Exchangeable, and Intracellular Pools.

PubMed

Garcia-Robledo, Emilio; Bohorquez, Julio; Corzo, Alfonso; Jimenez-Arias, Juan L; Papaspyrou, Sokratis

2016-01-01

The study of inorganic nutrients dynamics in shallow sediments usually focuses on two main pools: porewater (PW) nutrients and exchangeable (EX) ammonium and phosphate. Recently, it has been found that microphytobenthos (MPB) and other microorganisms can accumulate large amounts of nutrients intracellularly (IC), highlighting the biogeochemical importance of this nutrient pool. Storing nutrients could support the growth of autotrophs when nutrients are not available, and could also provide alternative electron acceptors for dissimilatory processes such as nitrate reduction. Here, we studied the magnitude and relative importance of these three nutrient pools (PW, IC, and EX) and their relation to chlorophylls (used as a proxy for MPB abundance) and organic matter (OM) contents in an intertidal mudflat of Cadiz Bay (Spain). MPB was localized in the first 4 mm of the sediment and showed a clear seasonal pattern; highest chlorophylls content was found during autumn and lowest during spring-summer. The temporal and spatial distribution of nutrients pools and MPB were largely correlated. Ammonium was higher in the IC and EX fractions, representing on average 59 and 37% of the total ammonium pool, respectively. Similarly, phosphate in the IC and EX fractions accounted on average for 40 and 31% of the total phosphate pool, respectively. Nitrate in the PW was low, suggesting low nitrification activity and rapid consumption. Nitrate accumulated in the IC pool during periods of moderate MPB abundance, being up to 66% of the total nitrate pool, whereas it decreased when chlorophyll concentration peaked likely due to a high nitrogen demand. EX-Nitrate accounted for the largest fraction of total sediment nitrate, 66% on average. The distribution of EX-Nitrate was significantly correlated with chlorophyll and OM, which probably indicates a relation of this pool to an increased availability of sites for ionic adsorption. This EX-Nitrate pool could represent an alternative nitrate source with significant concentrations available to the microbial community, deeper in the sediment below the oxic layer.

Biogeographic differences in soil biota promote invasive grass response to nutrient addition relative to co-occurring species despite lack of belowground enemy release.

PubMed

Broadbent, Arthur A D; Stevens, Carly J; Ostle, Nicholas J; Orwin, Kate H

2018-03-01

Multiple plant species invasions and increases in nutrient availability are pervasive drivers of global environmental change that often co-occur. Many plant invasion studies, however, focus on single-species or single-mechanism invasions, risking an oversimplification of a multifaceted process. Here, we test how biogeographic differences in soil biota, such as belowground enemy release, interact with increases in nutrient availability to influence invasive plant growth. We conducted a greenhouse experiment using three co-occurring invasive grasses and one native grass. We grew species in live and sterilized soil from the invader's native (United Kingdom) and introduced (New Zealand) ranges with a nutrient addition treatment. We found no evidence for belowground enemy release. However, species' responses to nutrients varied, and this depended on soil origin and sterilization. In live soil from the introduced range, the invasive species Lolium perenne L. responded more positively to nutrient addition than co-occurring invasive and native species. In contrast, in live soil from the native range and in sterilized soils, there were no differences in species' responses to nutrients. This suggests that the presence of soil biota from the introduced range allowed L. perenne to capture additional nutrients better than co-occurring species. Considering the globally widespread nature of anthropogenic nutrient additions to ecosystems, this effect could be contributing to a global homogenization of flora and the associated losses in native species diversity.

Is nitrogen transfer among plants enhanced by contrasting nutrient-acquisition strategies?

PubMed

Teste, François P; Veneklaas, Erik J; Dixon, Kingsley W; Lambers, Hans

2015-01-01

Nitrogen (N) transfer among plants has been found where at least one plant can fix N2 . In nutrient-poor soils, where plants with contrasting nutrient-acquisition strategies (without N2 fixation) co-occur, it is unclear if N transfer exists and what promotes it. A novel multi-species microcosm pot experiment was conducted to quantify N transfer between arbuscular mycorrhizal (AM), ectomycorrhizal (EM), dual AM/EM, and non-mycorrhizal cluster-rooted plants in nutrient-poor soils with mycorrhizal mesh barriers. We foliar-fed plants with a K(15) NO3 solution to quantify one-way N transfer from 'donor' to 'receiver' plants. We also quantified mycorrhizal colonization and root intermingling. Transfer of N between plants with contrasting nutrient-acquisition strategies occurred at both low and high soil nutrient levels with or without root intermingling. The magnitude of N transfer was relatively high (representing 4% of donor plant N) given the lack of N2 fixation. Receiver plants forming ectomycorrhizas or cluster roots were more enriched compared with AM-only plants. We demonstrate N transfer between plants of contrasting nutrient-acquisition strategies, and a preferential enrichment of cluster-rooted and EM plants compared with AM plants. Nutrient exchanges among plants are potentially important in promoting plant coexistence in nutrient-poor soils. © 2014 John Wiley & Sons Ltd.

Assessing the impact of nutrient enrichment in estuaries: susceptibility to eutrophication.

PubMed

Painting, S J; Devlin, M J; Malcolm, S J; Parker, E R; Mills, D K; Mills, C; Tett, P; Wither, A; Burt, J; Jones, R; Winpenny, K

2007-01-01

The main aim of this study was to develop a generic tool for assessing risks and impacts of nutrient enrichment in estuaries. A simple model was developed to predict the magnitude of primary production by phytoplankton in different estuaries from nutrient input (total available nitrogen and/or phosphorus) and to determine likely trophic status. In the model, primary production is strongly influenced by water residence times and relative light regimes. The model indicates that estuaries with low and moderate light levels are the least likely to show a biological response to nutrient inputs. Estuaries with a good light regime are likely to be sensitive to nutrient enrichment, and to show similar responses, mediated only by site-specific geomorphological features. Nixon's scale was used to describe the relative trophic status of estuaries, and to set nutrient and chlorophyll thresholds for assessing trophic status. Estuaries identified as being eutrophic may not show any signs of eutrophication. Additional attributes need to be considered to assess negative impacts. Here, likely detriment to the oxygen regime was considered, but is most applicable to areas of restricted exchange. Factors which limit phytoplankton growth under high nutrient conditions (water residence times and/or light availability) may favour the growth of other primary producers, such as macrophytes, which may have a negative impact on other biological communities. The assessment tool was developed for estuaries in England and Wales, based on a simple 3-category typology determined by geomorphology and relative light levels. Nixon's scale needs to be validated for estuaries in England and Wales, once more data are available on light levels and primary production.

Mathematical modelling of the influenced of diffusion rate on macro nutrient availability in paddy field

NASA Astrophysics Data System (ADS)

Renny; Supriyanto

2018-04-01

Nutrition is the chemical compounds that needed by the organism for the growth process. In plants, nutrients are organic or inorganic compounds that are absorbed from the roots of the soil. It consist of macro and micro nutrient. Macro nutrients are nutrition that needed by plants in large quantities, such as, nitrogen, calcium, pottacium, magnesium, and sulfur. The total soil nutrient is the difference between the input nutrient and the output nutrients. Input nutrients are nutrient that derived from the decomposition of organic substances. Meanwhile, the output nutrient consists of the nutrients that absorbed by plant roots (uptake), the evaporated nutrients (volatilized) and leached nutrients. The nutrient transport can be done through diffusion process. The diffusion process is essential in removing the nutrient from one place to the root surface. It will cause the rate of absorption of nutrient by the roots will be greater. Nutrient concept in paddy filed can be represented into a mathematical modelling, by making compartment models. The rate of concentration change in the compartment model forms a system of homogeneous linear differential equations. In this research, we will use Laplaces transformation to solve the compartment model and determined the dynamics of macro nutrition due to diffusion process.

Short-term effect of nutrient availability and rainfall distribution on biomass production and leaf nutrient content of savanna tree species.

PubMed

Barbosa, Eduardo R M; Tomlinson, Kyle W; Carvalheiro, Luísa G; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H T; van Langevelde, Frank

2014-01-01

Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use). Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna to test how water supply (even water supply vs. natural rainfall) and nutrient availability (no fertilisation vs. fertilisation) affects seedlings' above-ground biomass production and leaf-nutrient concentrations (N, P and K) of broad-leafed and fine-leafed tree species. Contrary to expectations, neither changes in water supply nor changes in soil nutrient level affected biomass production of the studied species. By contrast, leaf-nutrient concentration did change significantly. Under regular water supply, soil nutrient addition increased the leaf phosphorus concentration of both fine-leafed and broad-leafed species. However, under uneven water supply, leaf nitrogen and phosphorus concentration declined with soil nutrient supply, this effect being more accentuated in broad-leafed species. Leaf potassium concentration of broad-leafed species was lower when growing under constant water supply, especially when no NPK fertilizer was applied. We found that changes in environmental factors can affect leaf quality, indicating a potential interactive effect between land-use changes and environmental changes on savanna vegetation: under more uneven rainfall patterns within the growing season, leaf quality of tree seedlings for a number of species can change as a response to changes in nutrient levels, even if overall plant biomass does not change. Such changes might affect herbivore pressure on trees and thus savanna plant community dynamics. Although longer term experiments would be essential to test such potential effects of eutrophication via changes in leaf nutrient concentration, our findings provide important insights that can help guide management plans that aim to preserve savanna biodiversity.

Stimulatory Effects of Arsenic-Tolerant Soil Fungi on Plant Growth Promotion and Soil Properties

PubMed Central

Srivastava, Pankaj Kumar; Shenoy, Belle Damodara; Gupta, Manjul; Vaish, Aradhana; Mannan, Shivee; Singh, Nandita; Tewari, Shri Krishna; Tripathi, Rudra Deo

2012-01-01

Fifteen fungi were obtained from arsenic-contaminated agricultural fields in West Bengal, India and examined for their arsenic tolerance and removal ability in our previous study. Of these, the four best arsenic-remediating isolates were tested for plant growth promotion effects on rice and pea in the present study. A greenhouse-based pot experiment was conducted using soil inocula of individual fungi. The results indicated a significant (P<0.05) increase in plant growth and improvement of soil properties in inoculated soils compared to the control. A significant increase in plant growth was recorded in treated soils and varied from 16–293%. Soil chemical and enzymatic properties varied from 20–222% and 34–760%, respectively, in inoculated soil. Plants inoculated with inocula of Westerdykella and Trichoderma showed better stimulatory effects on plant growth and soil nutrient availability than Rhizopus and Lasiodiplodia. These fungi improved soil nutrient content and enhanced plant growth. These fungi may be used as bioinoculants for plant growth promotion and improved soil properties in arsenic-contaminated agricultural soils. PMID:23047145

Stimulatory effects of arsenic-tolerant soil fungi on plant growth promotion and soil properties.

PubMed

Srivastava, Pankaj Kumar; Shenoy, Belle Damodara; Gupta, Manjul; Vaish, Aradhana; Mannan, Shivee; Singh, Nandita; Tewari, Shri Krishna; Tripathi, Rudra Deo

2012-01-01

Fifteen fungi were obtained from arsenic-contaminated agricultural fields in West Bengal, India and examined for their arsenic tolerance and removal ability in our previous study. Of these, the four best arsenic-remediating isolates were tested for plant growth promotion effects on rice and pea in the present study. A greenhouse-based pot experiment was conducted using soil inocula of individual fungi. The results indicated a significant (P<0.05) increase in plant growth and improvement of soil properties in inoculated soils compared to the control. A significant increase in plant growth was recorded in treated soils and varied from 16-293%. Soil chemical and enzymatic properties varied from 20-222% and 34-760%, respectively, in inoculated soil. Plants inoculated with inocula of Westerdykella and Trichoderma showed better stimulatory effects on plant growth and soil nutrient availability than Rhizopus and Lasiodiplodia. These fungi improved soil nutrient content and enhanced plant growth. These fungi may be used as bioinoculants for plant growth promotion and improved soil properties in arsenic-contaminated agricultural soils.

[The impact of human activities on the dynamics of phosphorus in the environment and its effect on public health].

PubMed

de Quevedo, Claudia Maria Gomes; Paganini, Wanderley da Silva

2011-08-01

Phosphorus is a nutrient with finite and non-renewable sources, the speed of exploitation of which is currently far higher than the rates of return to its natural cycle. It is already being predicted that available and known sources will soon be exhausted, with serious and irreversible economic, social and environmental impacts. In this context, this study sets out to present information about the dynamics of phosphorus in the environment, assessing the impacts caused by human activities and establishing what actions might contribute to preservation of the nutrient cycle. To contribute to enhanced understanding of the topic, the evolution of data on population density, the number of industries and the extension of cultivated areas in a river basin, was studied over 22 years in relation to concentrations of phosphorus in water and sediment. The Tietê River was used for the case study. The results revealed that the control of domestic effluent, especially the amount of sodium tripolyphosphate (STPP) used in detergents and soap products, is of major importance for improving water quality, ensuring environmental protection and safeguarding public health.

Efficiency of C3 and C4 Plant Derived-Biochar for Cd Mobility, Nutrient Cycling and Microbial Biomass in Contaminated Soil.

PubMed

Bashir, Saqib; Shaaban, Muhammad; Mehmood, Sajid; Zhu, Jun; Fu, Qingling; Hu, Hongqing

2018-06-01

Biochar is considered a novel soil amendment to reduce metal mobility, but its influence on soil chemical and biochemical properties is not fully understood. In the present study, biochar derived from rice straw (RSB), rice hull (RHB), and maize stover (MSB) was used to evaluate comparative efficiency on Cd mobility and soil biochemical properties. Ammonium nitrate extractable Cd significantly decreased among all the applied biochar types and application rates. The European Community Bureau of Reference (BCR) technique showed significant decrease in acid-soluble Cd by 24%-32%, 19%-23%, and 22%-27% for RSB, RHB, and MSB, respectively at the 1.5% and 3% rate. However, the concentration of Cd in the residual increased by 38%, 35% and 36% for RSB, RHB and MSB, respectively at a 3% application rate. Soil microbial biomass (C and N) and inorganic nitrogen forms (NH 4 and NO 3 ) significantly increased among all biochar applications. Overall, RSB demonstrated positive results as soil amendments for Cd immobilization, increasing soil nutrient availability, and enhancing soil microbial biomass.

Amelioration and degradation of pressmud and bagasse wastes using vermitechnology.

PubMed

Bhat, Sartaj Ahmad; Singh, Jaswinder; Vig, Adarsh Pal

2017-11-01

This study evaluated the amelioration of pressmud (PM) and bagasse (BG) wastes by the vermiremediation process. The wastes were spiked with cattle dung (CD) in different concentrations to find out the best proportion supporting maximum earthworm growth and nutrients availability. The highest growth rate was observed in PMBG 50 (282.2mg/d/worm) feed mixture. Response surface design of earthworm growth parameters enumerated best concentration of wastes in CD with maximum value of 21.81% for earthworm number, 30.86% for earthworm weight, 27.09% for cocoons, 29.71% for hatchlings and 34.0% for hatchlings weight. Vermicomposting enhanced nutrient parameters like pH (6-8%), total kjeldahl nitrogen (19-48%), total phosphorus (9-67%), total calcium (13-111%), while decrease in total organic carbon (14-32%), electrical conductivity (21-30%), C:N ratio (36-51%), total potassium (9-19%) and total sodium (3-21%). Heavy metals in the final products were found to be under safe limits. SEM micrographs were more fragmented which indicated maturity and stability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Seasonal Belowground Ecosystem and Eco-enzymatic Responses to Soil pH and Phosphorus Availability in Temperate Hardwood Forests

NASA Astrophysics Data System (ADS)

Smemo, K. A.; Deforest, J. L.; Petersen, S. L.; Burke, D.; Hewins, C.; Kluber, L. A.; Kyker, S. R.

2013-12-01

Atmospheric acid deposition can increase phosphorus (P) limitation in temperate hardwood forests by increasing N availability, and therefore P demand, and/or by decreasing pH and occluding inorganic P. However, only recently have studies demonstrated that P limitation can occur in temperate forests and very little is known about the temporal aspects of P dynamics in acidic forest soils and how seasonal shifts in nutrient availability and demand influence microbial investment in extracellular enzymes. The objectives of this study were to investigate how P availability and soil pH influence seasonal patterns of nutrient cycling and soil microbial activity in hardwood forests that experience chronic acid deposition. We experimentally manipulated soil pH, P, or both for three years and examined soil treatment responses in fall, winter, spring, early summer, and late summer. We found that site (glaciated versus unglaciated) and treatment had the most significant influence on nutrient pools and cycling. In general, nutrient pools were higher in glaciated soils than unglaciated for measured nutrients, including total C and N (2-3 times higher), extractable inorganic nitrogen, and readily available P. Treatment had no impact on total C and N pools in either region, but did affect other measured nutrients such as ammonium, which was greatest in the elevated pH treatment for both sites. As expected, readily available P pools were highest in the elevated P treatments (3 fold increase in both sites), but raising pH decreased available P pools in the glaciated site. Raising soil pH increased both net N mineralization rates and net P mineralization rates, regardless of site. Nitrification responses were complex, but we observed an overall significant nitrification increase under elevated pH, particularly in the growing season. Extracellular enzyme activity showed more seasonal patterns than site and treatment effects, exhibiting significant growing season activity reductions for all enzymes measured. Phosphatase enzymes did not respond to our treatments and were generally greatest in the unglaciated soils, particularly in winter and spring. Enzyme stoichiometric relationships revealed that soil microbial populations in the glaciated site were consistently less P and N-limited than unglaciated sites but this difference was less pronounced during the growing season. The trajectory of nutrient limitation in response to soil pH and P availability was highly variable, but we observed that enzyme ratios in the early summer were particularly shifted relative to other seasons suggesting that both sites were increasingly P and N-limited during this period. Overall, our results suggest that ecosystem and microbial responses to soil pH and P availability vary with both season and site history and that more spatially and temporally explicit observations are needed to improve our understanding of ecosystem acidification, nutrient limitation, and the cost-benefit relationships of microbial investments in extracellular enzymes.

Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

DOE PAGES

Knelman, Joseph E.; Graham, Emily B.; Ferrenberg, Scott; ...

2017-09-15

In post-disturbance landscapes nutrient availability has proven a major control on ecological succession. In this study, we examined variation in connections between soil nutrient availability and decomposition extracellular enzyme activity (EEA) across post fire secondary succession in forest soils as well as after a secondary flood disturbance. We also examined possible linkages between edaphic properties and bacterial communities based on 16S rRNA gene analysis. We found that with advancing succession in a post-fire landscape, the relationship between soil nutrients and EEA became stronger over time. In general, late successional soils showed stronger connections between EEA and soil nutrient status, whilemore » early successional soils were marked by a complete decoupling of nutrients and EEA. We also found that soil moisture and bacterial communities of post-fire disturbance soils were susceptible to change following the secondary flood disturbance, while undisturbed, reference forest soils were not. Our results demonstrate that nutrient pools correlating with EEA change over time. While past work has largely focused on ecosystem succession on decadal timescales, our work suggests that nutrients shift in their relative importance as a control of decomposition EEA in the earliest stages of secondary succession. Furthermore, this work emphasizes the relevance of successional stage, even on short timescales, in predicting rates of carbon and nitrogen cycling, especially as disturbances become more frequent in a rapidly changing world.« less

Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knelman, Joseph E.; Graham, Emily B.; Ferrenberg, Scott

In post-disturbance landscapes nutrient availability has proven a major control on ecological succession. In this study, we examined variation in connections between soil nutrient availability and decomposition extracellular enzyme activity (EEA) across post fire secondary succession in forest soils as well as after a secondary flood disturbance. We also examined possible linkages between edaphic properties and bacterial communities based on 16S rRNA gene analysis. We found that with advancing succession in a post-fire landscape, the relationship between soil nutrients and EEA became stronger over time. In general, late successional soils showed stronger connections between EEA and soil nutrient status, whilemore » early successional soils were marked by a complete decoupling of nutrients and EEA. We also found that soil moisture and bacterial communities of post-fire disturbance soils were susceptible to change following the secondary flood disturbance, while undisturbed, reference forest soils were not. Our results demonstrate that nutrient pools correlating with EEA change over time. While past work has largely focused on ecosystem succession on decadal timescales, our work suggests that nutrients shift in their relative importance as a control of decomposition EEA in the earliest stages of secondary succession. Furthermore, this work emphasizes the relevance of successional stage, even on short timescales, in predicting rates of carbon and nitrogen cycling, especially as disturbances become more frequent in a rapidly changing world.« less

Growth, biomass allocation and nutrient use efficiency in Cladium jamaicense and Typha domingensis as affected by phosphorus and oxygen availability

USGS Publications Warehouse

Lorenzen, B.; Brix, H.; Mendelssohn, I.A.; McKee, K.L.; Miao, S.L.

2001-01-01

The effects of phosphorus (P) and oxygen availability on growth, biomass allocation and nutrient use efficiency in Cladium jamaicense Crantz and Typha domingensis Pers. were studied in a growth facility equipped with steady-state hydroponic rhizotrons. The treatments included four P concentrations (10, 40, 80 and 500 ??g I-1) and two oxygen concentration (8.0 and <0.5 mg O2 I-1) in the culture solutions. In Cladium, no clear relationship was found between P availability and growth rate (19-37 mg g-1 d-1), the above to below ground biomass ratio (A/B) (mean = 4.6), or nitrogen use efficiency (NUE) (mean = 72 g dry weight g-1 N). However, the ratio between root supported tissue (leaves, rhizomes and ramets) and root biomass (S/R) (5.6-8) increased with P availability. In contrast, the growth rate (48-89 mg g-1 d-1) and the biomass ratios A/B (2.4-6.1) and S/R (5.4-10.3) of Typha increased with P availability, while NUE (71-30 g dry weight g-1 N) decreased. The proportion of root laterals was similar in the two species, but Typha had thinner root laterals (diameter = 186 ??m) than Cladium (diameter = 438 ??m) indicating a larger root surface area in Typha. The two species had a similar P use efficiency (PUE) at 10 ??g PI-1 (mean = 1134 g dry weight g-1 P) and at 40 and 80 ??g PI-1 (mean = 482 dry weight g-1 P) but the N/P ratio indicated imbalances in nutrient uptake at a higher P concentration (40 ??g PI-1) in Typha than in Cladium (10 ??g PI-1). The two species had similar root specific P accumulation rate at the two lowest P levels, whereas Typha had 3-13-fold higher P uptake rates at the two highest P levels, indicating a higher nutrient uptake capacity in Typha. The experimental oxygen concentration in the rhizosphere had only limited effect on the growth of the two species and had little effect on biomass partitioning and nutrient use efficiency. The aerenchyma in these species was probably sufficient to maintain adequate root oxygenation under partially oxygen depleted conditions. Cladium had characteristics typical for plants from nutrient poor habitats, which included slow growth rate, low capacity for P uptake and relatively inflexible biomass partitioning in response to increased P availability. In contrast, Typha demonstrated a high degree of flexibility in growth, biomass partitioning, and nutrient accumulation to P availability, similar to species from nutrient rich habitats. Although the N/P ratio indicated that Typha was more nutrient stressed at the low P levels, Typha had a higher capacity for P uptake and was more competitive than Cladium at the applied P concentrations. ?? 2001 Elsevier Science B.V.

Contrasting bacterial communities in two indigenous Chionochloa (Poaceae) grassland soils in New Zealand

PubMed Central

Griffith, Jocelyn C.; Lee, William G.; Orlovich, David A.

2017-01-01

The cultivation of grasslands can modify both bacterial community structure and impact on nutrient cycling as well as the productivity and diversity of plant communities. In this study, two pristine New Zealand grassland sites dominated by indigenous tall tussocks (Chionochloa pallens or C. teretifolia) were examined to investigate the extent and predictability of variation of the bacterial community. The contribution of free-living bacteria to biological nitrogen fixation is predicted to be ecologically significant in these soils; therefore, the diazotrophic community was also examined. The C. teretifolia site had N-poor and poorly-drained peaty soils, and the C. pallens had N-rich and well-drained fertile soils. These soils also differ in the proportion of organic carbon (C), Olsen phosphorus (P) and soil pH. The nutrient-rich soils showed increased relative abundances of some copiotrophic bacterial taxa (including members of the Proteobacteria, Bacteroidetes and Firmicutes phyla). Other copiotrophs, Actinobacteria and the oliogotrophic Acidobacteria showed increased relative abundance in nutrient-poor soils. Greater diversity based on 16S rRNA gene sequences and the Tax4Fun prediction of enhanced spore formation associated with nutrient-rich soils could indicate increased resilience of the bacterial community. The two sites had distinct diazotrophic communities with higher diversity in C. teretifolia soils that had less available nitrate and ammonium, potentially indicating increased resilience of the diazotroph community at this site. The C. teretifolia soils had more 16S rRNA gene and nifH copies per g soil than the nutrient rich site. However, the proportion of the bacterial community that was diazotrophic was similar in the two soils. We suggest that edaphic and vegetation factors are contributing to major differences in the composition and diversity of total bacterial and diazotrophic communities at these sites. We predict the differences in the communities at the two sites will result in different responses to environmental change. PMID:28658306

Primary Respiratory Chain Disease Causes Tissue-Specific Dysregulation of the Global Transcriptome and Nutrient-Sensing Signaling Network

PubMed Central

Zhang, Zhe; Tsukikawa, Mai; Peng, Min; Polyak, Erzsebet; Nakamaru-Ogiso, Eiko; Ostrovsky, Julian; McCormack, Shana; Place, Emily; Clarke, Colleen; Reiner, Gail; McCormick, Elizabeth; Rappaport, Eric; Haas, Richard; Baur, Joseph A.; Falk, Marni J.

2013-01-01

Primary mitochondrial respiratory chain (RC) diseases are heterogeneous in etiology and manifestations but collectively impair cellular energy metabolism. Mechanism(s) by which RC dysfunction causes global cellular sequelae are poorly understood. To identify a common cellular response to RC disease, integrated gene, pathway, and systems biology analyses were performed in human primary RC disease skeletal muscle and fibroblast transcriptomes. Significant changes were evident in muscle across diverse RC complex and genetic etiologies that were consistent with prior reports in other primary RC disease models and involved dysregulation of genes involved in RNA processing, protein translation, transport, and degradation, and muscle structure. Global transcriptional and post-transcriptional dysregulation was also found to occur in a highly tissue-specific fashion. In particular, RC disease muscle had decreased transcription of cytosolic ribosomal proteins suggestive of reduced anabolic processes, increased transcription of mitochondrial ribosomal proteins, shorter 5′-UTRs that likely improve translational efficiency, and stabilization of 3′-UTRs containing AU-rich elements. RC disease fibroblasts showed a strikingly similar pattern of global transcriptome dysregulation in a reverse direction. In parallel with these transcriptional effects, RC disease dysregulated the integrated nutrient-sensing signaling network involving FOXO, PPAR, sirtuins, AMPK, and mTORC1, which collectively sense nutrient availability and regulate cellular growth. Altered activities of central nodes in the nutrient-sensing signaling network were validated by phosphokinase immunoblot analysis in RC inhibited cells. Remarkably, treating RC mutant fibroblasts with nicotinic acid to enhance sirtuin and PPAR activity also normalized mTORC1 and AMPK signaling, restored NADH/NAD+ redox balance, and improved cellular respiratory capacity. These data specifically highlight a common pathogenesis extending across different molecular and biochemical etiologies of individual RC disorders that involves global transcriptome modifications. We further identify the integrated nutrient-sensing signaling network as a common cellular response that mediates, and may be amenable to targeted therapies for, tissue-specific sequelae of primary mitochondrial RC disease. PMID:23894440

Effects of prescribed fire on wildlife and wildlife habitat in selected ecosystems of North America

Treesearch

William M. Block; L. Mike Conner; Paul A. Brewer; Paulette Ford; Jonathan Haufler; Andrea Litt; Ronald E. Masters; Laura R. Mitchell; Jane Park

2016-01-01

Prescribed fire is applied widely as a management tool in North America to meet various objectives such as reducing fuel loads and fuel continuity, returning fire to an ecosystem, enhancing wildlife habitats, improving forage, preparing seedbeds, improving watershed conditions, enhancing nutrient cycling, controlling exotic weeds, and enhancing resilience from...

Canopy leaf area constrains [CO2]-induced enhancement of productivity and partitioning among aboveground carbon pools.

Treesearch

Heather R. McCarthy; Ram Oren; Adrien C. Finzi; Kurt H. Johnsen

2006-01-01

Net primary productivity (NPP) is enhanced under future atmospheric [CO2] in temperate forests representing a broad range of productivity. Yet questions remain in regard to how elevated [CO2]-induced NPP enhancement may be affected by climatic variations and limiting nutrient resources, as well as how this additional...

Linking Soil Microbial Ecology to Ecosystem Functioning in Integrated Crop-Livestock Systems

USDA-ARS?s Scientific Manuscript database

Enhanced soil stability, nutrient cycling and C sequestration potential are important ecosystem functions driven by soil microbial processes and are directly influenced by agricultural management. Integrated crop-livestock agroecosystems (ICL) can enhance these functions via high-residue returning c...

Effects of thinning, residue mastication, and prescribed fire on soil and nutrient budgets in a Sierra Nevada mixed-conifer forest

USDA-ARS?s Scientific Manuscript database

The effects of thinning followed by residue mastication (THIN), prescribed fire (BURN), and thinning plus residue mastication plus burning (T+B) on nutrient budgets and resin-based (plant root simulator [PRS] probe) measurements of soil nutrient availability in a mixed-conifer forest were measured. ...

Effects of thinning, residue mastication, and prescribed fire on soil and nutrient budgets in a Sierra Nevada mixed conifer forest

USDA-ARS?s Scientific Manuscript database

The effects of thinning followed by residue mastication (THIN), prescribed fire (BURN), and thinning plus residue mastication plus burning (T+B) on nutrient budgets and resin-based (plant root simulator [PRS] probe) measurements of soil nutrient availability in a mixed-conifer forest were measured. ...

Fiddler crabs facilitate Spartina alterniflora growth, mitigating periwinkle overgrazing of marsh habitat.

PubMed

Gittman, Rachel K; Keller, Danielle A

2013-12-01

Ecologists have long been interested in identifying and testing factors that drive top-down or bottom-up regulation of communities. Most studies have focused on factors that directly exert top-down (e.g., grazing) or bottom-up (e.g., nutrient availability) control on primary production. For example, recent studies in salt marshes have demonstrated that fronts of Littoraria irrorata periwinkles can overgraze Spartina alterniflora and convert marsh to mudflat. The importance of indirect, bottom-up effects, particularly facilitation, in enhancing primary production has also recently been explored. Previous field studies separately revealed that fiddler crabs, which burrow to depths of more than 30 cm, can oxygenate marsh sediments and redistribute nutrients, thereby relieving the stress of anoxia and enhancing S. alterniflora growth. However, to our knowledge, no studies to date have explored how nontrophic facilitators can mediate top-down effects (i.e., grazing) on primary-producer biomass. We conducted a field study testing whether fiddler crabs can facilitate S. alterniflora growth sufficiently to mitigate overgrazing by periwinkles and thus sustain S. alterniflora marsh. As inferred from contrasts to experimental plots lacking periwinkles and fiddler crabs, periwinkles alone exerted top-down control of total aboveground biomass and net growth of S. alterniflora. When fiddler crabs were included, they counteracted the effects of periwinkles on net S. alterniflora growth. Sediment oxygen levels were greater and S. alterniflora belowground biomass was lower where fiddler crabs were present, implying that fiddler crab burrowing enhanced S. alterniflora growth. Consequently, in the stressful interior S. alterniflora marsh, where subsurface soil anoxia is widespread, fiddler crab facilitation can mitigate top-down control by periwinkles and can limit and possibly prevent loss of biogenically structured marsh habitat and its ecosystem services.

Light exposure enhances urea absorption in the fluted giant clam, Tridacna squamosa, and up-regulates the protein abundance of a light-dependent urea active transporter, DUR3-like, in its ctenidium.

PubMed

Chan, Christabel Y L; Hiong, Kum C; Boo, Mel V; Choo, Celine Y L; Wong, Wai P; Chew, Shit F; Ip, Yuen K

2018-04-19

Giant clams live in nutrient-poor reef waters of the Indo-Pacific and rely on symbiotic dinoflagellates ( Symbiodinium spp., also known as zooxanthellae) for nutrients. As the symbionts are nitrogen deficient, the host clam has to absorb exogenous nitrogen and supply it to them. This study aimed to demonstrate light-enhanced urea absorption in the fluted giant clam, Tridacna squamosa , and to clone and characterize the urea active transporter DUR3-like from its ctenidium (gill). The results indicate that T. squamosa absorbs exogenous urea, and the rate of urea uptake in the light was significantly higher than that in darkness. The DUR3-like coding sequence obtained from its ctenidium comprised 2346 bp, encoding a protein of 782 amino acids and 87.0 kDa. DUR3-like was expressed strongly in the ctenidium, outer mantle and kidney. Twelve hours of exposure to light had no significant effect on the transcript level of ctenidial DUR3-like However, between 3 and 12 h of light exposure, DUR3-like protein abundance increased progressively in the ctenidium, and became significantly greater than that in the control at 12 h. DUR3-like had an apical localization in the epithelia of the ctenidial filaments and tertiary water channels. Taken together, these results indicate that DUR3-like might participate in light-enhanced urea absorption in the ctenidium of T. squamosa When made available to the symbiotic zooxanthellae that are known to possess urease, the absorbed urea can be metabolized to NH 3 and CO 2 to support amino acid synthesis and photosynthesis, respectively, during insolation. © 2018. Published by The Company of Biologists Ltd.

Plant and microbial responses to nitrogen and phosphorus addition across an elevational gradient in subarctic tundra.

PubMed

Sundqvist, Maja K; Liu, Zhanfeng; Giesler, Reiner; Wardle, David A

2014-07-01

Temperature and nutrients are major limiting factors in subarctic tundra. Experimental manipulation of nutrient availability along elevational gradients (and thus temperature) can improve our understanding of ecological responses to climate change. However, no study to date has explored impacts of nutrient addition along a tundra elevational gradient, or across contrasting vegetation types along any elevational gradient. We set up a full factorial nitrogen (N) and phosphorus (P) fertilization experiment in each of two vegetation types (heath and meadow) at 500 m, 800 m, and 1000 m elevation in northern Swedish tundra. We predicted that plant and microbial communities in heath or at lower elevations would be more responsive to N addition while communities in meadow or at higher elevations would be more responsive to P addition, and that fertilizer effects would vary more with elevation for the heath than for the meadow. Although our results provided little support for these predictions, the relationship between nutrient limitation and elevation differed between vegetation types. Most plant and microbial properties were responsive to N and/or P fertilization, but responses often varied with elevation and/or vegetation type. For instance, vegetation density significantly increased with N + P fertilization relative to the other fertilizer treatments, and this increase was greatest at the lowest elevation for the heath but at the highest elevation for the meadow. Arbuscular mycorrhizae decreased with P fertilization at 500 m for the meadow, but with all fertilizer treatments in both vegetation types at 800 m. Fungal to bacterial ratios were enhanced by N+ P fertilization for the two highest elevations in the meadow only. Additionally, microbial responses to fertilization were primarily direct rather than indirect via plant responses, pointing to a decoupled response of plant and microbial communities to nutrient addition and elevation. Because our study shows how two community types differ in their responses to fertilization and elevation, and because the temperature range across this gradient is approximately 3 degrees C, our study is informative about how nutrient limitation in tundra may be influenced by temperature shifts that are comparable to those expected under climate change during this century.