Browsing by Subject "NITRATE"

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  • Salonen, Iines S.; Chronopoulou, Panagiota-Myrsini; Nomaki, Hidetaka; Langlet, Dewi; Tsuchiya, Masashi; Koho, Karoliina A. (2021)
    Foraminifera are unicellular eukaryotes that are an integral part of benthic fauna in many marine ecosystems, including the deep sea, with direct impacts on benthic biogeochemical cycles. In these systems, different foraminiferal species are known to have a distinct vertical distribution, i.e., microhabitat preference, which is tightly linked to the physico-chemical zonation of the sediment. Hence, foraminifera are well-adapted to thrive in various conditions, even under anoxia. However, despite the ecological and biogeochemical significance of foraminifera, their ecology remains poorly understood. This is especially true in terms of the composition and diversity of their microbiome, although foraminifera are known to harbor diverse endobionts, which may have a significant meaning to each species' survival strategy. In this study, we used 16S rRNA gene metabarcoding to investigate the microbiomes of five different deep-sea benthic foraminiferal species representing differing microhabitat preferences. The microbiomes of these species were compared intra- and inter-specifically, as well as with the surrounding sediment bacterial community. Our analysis indicated that each species was characterized with a distinct, statistically different microbiome that also differed from the surrounding sediment community in terms of diversity and dominant bacterial groups. We were also able to distinguish specific bacterial groups that seemed to be strongly associated with particular foraminiferal species, such as the family Marinilabiliaceae for Chilostomella ovoidea and the family Hyphomicrobiaceae for Bulimina subornata and Bulimina striata. The presence of bacterial groups that are tightly associated to a certain foraminiferal species implies that there may exist unique, potentially symbiotic relationships between foraminifera and bacteria that have been previously overlooked. Furthermore, the foraminifera contained chloroplast reads originating from different sources, likely reflecting trophic preferences and ecological characteristics of the different species. This study demonstrates the potential of 16S rRNA gene metabarcoding in resolving the microbiome composition and diversity of eukaryotic unicellular organisms, providing unique in situ insights into enigmatic deep-sea ecosystems.
  • Allen, John A.; Setälä, Heikki; Kotze, David Johan (2020)
    Urban residents and their pets utilize urban greenspaces daily. As urban dog ownership rates increase globally, urban greenspaces are under mounting pressure even as the benefits and services they provide become more important. The urine of dogs is high in nitrogen (N) and may represent a significant portion of the annual urban N load. We examined the spatial distribution and impact of N deposition from dog urine on soils in three urban greenspace typologies in Finland: Parks, Tree Alleys, and Remnant Forests. We analyzed soil from around trees, lampposts and lawn areas near walking paths, and compared these to soils from lawn areas 8 m away from pathways. Soil nitrate, ammonium, total N concentrations, and electrical conductivity were significantly higher and soil pH significantly lower near path-side trees and poles relative to the 8 m lawn plots. Also, stable isotope analysis indicates that the primary source of path-side N are distinct from those of the 8 m lawn plots, supporting our hypothesis that dogs are a significant source of N in urban greenspaces, but that this deposition occurs in a restricted zone associated with walking paths. Additionally, we found that Remnant Forests were the least impacted of the three typologies analyzed. We recommend that landscape planners acknowledge this impact, and design parks to reduce or isolate this source of N from the wider environment.
  • Neitola, Kimmo; Brus, David; Makkonen, Ulla; Sipila, Mikko; Lihavainen, Heikki; Kulmala, Markku (2014)
  • Hurkuck, Miriam; Bruemmer, Christian; Mohr, Karsten; Spott, Oliver; Well, Reinhard; Flessa, Heinz; Kutsch, Werner L. (2015)
    We applied a N-15 dilution technique called Integrated Total Nitrogen Input (ITNI) to quantify annual atmospheric N input into a peatland surrounded by intensive agricultural practices over a 2-year period. Grass species and grass growth effects on atmospheric N deposition were investigated using Lolium multiflorum and Eriophorum vaginatum and different levels of added N resulting in increased biomass production. Plant biomass production was positively correlated with atmospheric N uptake (up to 102.7mg N pot(-1)) when using Lolium multiflorum. In contrast, atmospheric N deposition to Eriophorum vaginatum did not show a clear dependency to produced biomass and ranged from 81.9 to 138.2mgNpot(-1). Both species revealed a relationship between atmospheric N input and total biomass N contents. Airborne N deposition varied from about 24 to 55kgNha(-1)yr(-1). Partitioning of airborne N within the monitor system differed such that most of the deposited N was found in roots of Eriophorum vaginatum while the highest share was allocated in aboveground biomass of Lolium multiflorum. Compared to other approaches determining atmospheric N deposition, ITNI showed highest airborne N input and an up to fivefold exceedance of the ecosystem-specific critical load of 5-10kgNha(-1)yr(-1).
  • Konig, Walter; Konig, Emilia; Elo, Kari; Vanhatalo, Aila; Jaakkola, Seija (2019)
    Legumes are particularly susceptible to clostridial fermentation when ensiled because of their high buffering capacity and water-soluble carbohydrate contents. The aim of the study was to investigate if a sodium nitrite treatment (900 g t(-1) herbage in fresh matter [FM]) impairs butyric acid fermentation of red clover-timothy-meadow fescue silage compared with formic acid-treated (4 l t(-1) FM) and untreated silage. The sward was harvested after wilting at low dry matter (DM) (LDM, 194 g kg(-1)) and high DM (HDM, 314 g kg(-1)) concentrations and half of the herbage batches were inoculated with Clostridium tyrobutyricum spores before additive treatments. No butyric acid fermentation was observed in HDM silages probably because of the relatively high DM and nitrate contents of the herbage mixture. In LDM silage butyric acid was detected only in formic acid-treated silage, and the number of clostridia copies was higher in formic acid-treated than in sodium nitrite treated silage. Sodium nitrite treatment was superior to FA treatment in suppressing clostridial fermentation in the LDM silages.
  • Saarenheimo, Jatta; Rissanen, Antti J.; Arvola, Lauri; Nykänen, Hannu; Lehmann, Moritz F.; Tiirola, Marja (2015)
    We studied potential links between environmental factors, nitrous oxide (N2O) accumulation, and genetic indicators of nitrite and N2O reducing bacteria in 12 boreal lakes. Denitrifying bacteria were investigated by quantifying genes encoding nitrite and N2O reductases (nirS/nirK and nosZ, respectively, including the two phylogenetically distinct clades nosZ(I) and nosZ(II)) in lake sediments. Summertime N2O accumulation and hypolimnetic nitrate concentrations were positively correlated both at the inter-lake scale and within a depth transect of an individual lake (Lake Vanajavesi). The variability in the individual nirS, nirK, nosZ(I), and nosZ(II) gene abundances was high (up to tenfold) among the lakes, which allowed us to study the expected links between the ecosystem's nir-vs-nos gene inventories and N2O accumulation. Inter-lake variation in N2O accumulation was indeed connected to the relative abundance of nitrite versus N2O reductase genes, i.e. the (nirS+nirK)/nosZ(I) gene ratio. In addition, the ratios of (nirS+ nirK)/nosZ(I) at the inter-lake scale and (nirS+ nirK)/nosZ(I+II) within Lake Vanajavesi correlated positively with nitrate availability. The results suggest that ambient nitrate concentration can be an important modulator of the N2O accumulation in lake ecosystems, either directly by increasing the overall rate of denitrification or indirectly by controlling the balance of nitrite versus N2O reductase carrying organisms.
  • König, Walter; Konig, Emilia; Weiss, Kirsten; Tuomivirta, Tero T.; Fritze, Hannu; Elo, Kari; Vanhatalo, Aila; Jaakkola, Seija (2019)
    BACKGROUND Nitrite and hexamine are used as silage additives because of their adverse effects on Clostridia and Clostridia spores. The effect of sodium nitrite and sodium nitrite/hexamine mixtures on silage quality was investigated. A white lupin-wheat mixture was treated with sodium nitrite (NaHe0) (900 g t(-1) forage), or mixtures of sodium nitrite (900 g t(-1)) and hexamine. The application rate of hexamine was 300 g t(-1) (NaHe300) or 600 g t(-1) (NaHe600). Additional treatments were the untreated control (Con), and formic acid (FA) applied at a rate of 4 L t(-1) (1000 g kg(-1)). RESULTS Additives improved silage quality noticeably only by reducing silage ammonia content compared with the control. The addition of hexamine to a sodium nitrite solution did not improve silage quality compared with the solution containing sodium nitrite alone. The increasing addition of hexamine resulted in linearly rising pH values (P <0.001) and decreasing amounts of lactic acid (P <0.01). Sodium nitrite based additives were more effective than formic acid in preventing butyric acid formation. Additives did not restrict the growth of Saccharomyces cerevisiae compared to the control. CONCLUSION The addition of hexamine did not improve silage quality compared with a solution of sodium nitrite. (c) 2018 Society of Chemical Industry
  • Lassmann-Klee, Paul Guenther; Lehtimäki, Lauri; Lindholm, Tuula; Malmberg, L. Pekka; Sovijärvi, Anssi; Piirilä, Päivi (2018)
    Fractional exhaled nitric oxide (F-ENO) is used to assess eosinophilic inflammation of the airways. F-ENO values are influenced by the expiratory flow rate and orally produced NO. We measured F-ENO at four different expiratory flow levels after two different mouthwashes: tap water and carbonated water. Further, we compared the alveolar NO concentration (C-ANO), maximum airway NO flux (J(awNO)) and airway NO diffusion (D-awNO) after these two mouthwashes. F-ENO was measured in 30 volunteers (healthy or asthmatic) with a chemiluminescence NO-analyser at flow rates of 30, 50, 100 and 300mL/s. A mouthwash was performed before the measurement at every flow rate. The carbonated water mouthwash significantly reduced F-ENO compared to the tap water mouthwash at all expiratory flows: 50mL/s (p
  • Kalu, Subin; Simojoki, Asko; Karhu, Kristiina; Tammeorg, Priit (2021)
    Biochars (BC) have tremendous potential in mitigating climate change, and offer various agricultural and environmental benefits. However, there is limited information about the long-term effects of added biochars particularly from boreal regions. We studied the effects of a single application of softwood biochars on two contrasting boreal agricultural soils (nutrient-poor, coarse textured Umbrisol and fertile, fine-textured Stagnosol), both with high initial soil organic carbon contents, over eight years following the application. We focused on plant nutrient contents and nutrient uptake dynamics of different field crops over these years, as well as on soil physical properties and greenhouse gas emissions during seven to nine growing seasons. We found that, added biochars had minor long-term effects on the crop biomass yield, plant nutrient contents and plant nutrient uptake in both soil types. In terms of crop biomass yields, significant biochar × fertilization interactions were observed in barley (in 2013) and peas (in 2016), three and six years after the application of biochar in Stagnosol, respectively. In both cases, the biochar combined with the normal fertilization rate (100% of the recommended value) significantly increased crop biomass yield compared to corresponding fertilization treatment without biochar. However, the biochar had no effect at a lower fertilization rate (30% of the recommended value). Similar significant biochar × fertilization interactions were observed for several plant nutrient contents for peas in 2016, and for uptake for both barley in 2013 and peas in 2016. Thus, the ability of biochar to enhance the supply of nutrients to plants and hence to improve the crop biomass yield exists in boreal conditions, although these effects were minimal and not consistent over the years. Biochar notably increased plant K content, and also increased K:Mg ratio in plant biomass, suggesting a possible antagonistic effect of K on Mg in Umbrisol. Similar K antagonism on Na was observed in Stagnosol. The applied biochar also reduced the plant content and uptake of Al and Na in several years in Stagnosol. Furthermore, we found that, increased plant Mn content with biochar in the initial years subsequently declined over the following years in Umbrisol. On the other hand, the relative plant contents of Cd and Ni in Umbrisol, and P, K, Mg, S, Al, Cu, Fe and Ni in Stagnosol increased over the years. Despite these increased plant contents, no significant improvement was observed in crop biomass yield by added biochar over the years. The enhanced plant available water and reduced bulk density previously reported during the initial years were faded in long-term, likely due to dilution of biochar concentration in topsoil. However, the potential of biochar to affect N2O emission persisted, even seven years after the application.
  • Uusheimo, Sari Anneli; Tulonen, Tiina Valpuri; Aalto, Sanni L.; Arvola, Lauri Matti Juhani (2018)
    Constructed agricultural ponds and wetlands can reduce nitrogen loading from agriculture especially in areas where warm climate predominates. However, in cold climate temperature-dependency of microbiological processes have raised the question about the applicability of constructed wetlands in N removal. We measured in situ denitrification rates in a constructed agricultural pond using N-15-isotope pairing technique at ambient light and temperature throughout a year as well as diurnally. The field IPT measurements were combined with a wide set of potentially important explanatory data, including air temperature, photosynthetically active radiation, precipitation, discharge, nitrate plus other water quality variables, sediment temperature, oxygen concentration and penetration depth, diffusive oxygen uptake and sediment organic carbon. Denitrification varied, on average, diurnally between 12 and 314 mu mol N m(-2) h(-1) and seasonally between 0 and 12409 mu mol m(-2) h(-1). Light and oxygen regulated the diel variation of denitrification, but seasonally denitrification was governed by a combination of temperature, oxygen and turbidity. The results indicated that the real N removal rate might be 30-35% higher than the measured daytime rates, suggesting that neglecting the diel variation of denitrification we may underestimate N removal capacity of shallow sediments. We conclude, that by following recommended wetland:catchment - size ratios, boreal agricultural ponds can efficiently remove nitrogen by denitrification in summer and in autumn, while in winter and in spring the contribution of denitrification might be negligible relative to the loading, especially with short residence time.
  • Kakaei Lafdani, Elham; Laurén, Ari; Cvetkovic, Jovana; Pumpanen, Jukka; Saarela, Taija; Palviainen, Marjo (2021)
    Forest regeneration operations increase the concentration of nitrogen (N) in watercourses especially outside the growing season when traditional biological water protection methods are inefficient. Biochar adsorption-based water treatment could be a solution for nutrient retention. We studied the total nitrogen (TN) and nitrate-nitrogen (NO3--N) adsorption-desorption properties of spruce and birch biochar. The adsorption test was performed under four different initial concentrations of TN (1, 2, 3, and 4 mg L-1) using forest runoff water collected from ditch drains of boreal harvested peatland. The results showed that the TN adsorption amount increased linearly from the lowest to the highest concentration. The maximum adsorption capacity was 2.4 and 3.2 times greater in the highest concentration (4 mg L-1) compared to the lowest concentration (1 mg L-1) in spruce and birch biochar, respectively. The NO3--N adsorption amount of birch biochar increased linearly from 0 to 0.15 mg NO3--N g biochar(-1) when the initial concentration of NO3--N increased from 0.2 to 1.4 mg L-1. However, in spruce biochar, the initial concentration did not affect NO3--N adsorption amount. The results indicate that concentration significantly affects the biochar's capacity to adsorb N from water. The desorption test was performed by adding biochar extracted from the adsorption test into the forest runoff water with low TN concentration (0.2 or 0.35 mg L-1). The desorption results showed that desorption was negligibly small, and it was dependent on the TN concentration for birch biochar. Therefore, biochar can be a complementary method supporting water purification in peatland areas.
  • Nie, Wei; Ding, Aijun; Wang, Tao; Kerminen, Veli-Matti; George, Christian; Xue, Likun; Wang, Wenxing; Zhang, Qingzhu; Petäjä, Tuukka; Qi, Ximeng; Gao, Xiaomei; Wang, Xinfeng; Yang, Xiuqun; Fu, Congbin; Kulmala, Markku (2014)
  • Karhu, Kristiina; Kalu, Subin; Seppänen, Aino; Kitzler, Barbara; Virtanen, Eetu (2021)
    Addition of biochar to soil has been shown to reduce nitrogen (N) leaching in pot experiments, but direct field measurements are scarce, and data is lacking especially from colder, boreal conditions. We studied the effect of soil organic amendments on nitrate (NO3-) and ammonium (NH4+) leaching using the resin bag method, by placing the bags containing ion-exchange resins under the plough layer. We compared N leaching under five different treatments at the Päästösäästö project site (Soilfood Oy) in Parainen, south-western Finland: non-fertilized control, fertilized control, and three different organic amendments: spruce biochar, willow biochar and nutrient fiber. During the 2017 growing season, resin bags were changed monthly between the end of May and beginning of September, extracted with 1 M NaCl, and analyzed for inorganic N. The daily leaching rate of NO3- was greatest at the beginning of the growing season, right after fertilization. Ammonium leaching was generally lower, and independent of the time since fertilization. The spruce biochar reduced cumulative NO3- leaching by 68% compared to the fertilized control. The NH4+leaching in the organic amendment treatments did not statistically significantly differ from the fertilized control in pairwise comparisons. In October 2017, after harvesting, the resin bags were placed under soil columns again, and left in the soil over winter to accumulate N leached during the plant-free period. Cumulative NO3- leaching during winter was consistent with the corresponding summer results, and average leaching decreased in the order: willow biochar >fertilized control >nutrient fiber >non-fertilized control >spruce biochar. Thus, we show here, for the first time in a field study from boreal conditions that spruce biochar soil application decreased nitrate leaching, while increasing its retention in the surface layer of the biochar-amended soil.
  • Makkonen, Ulla; Virkkula, Aki; Hellén, Heidi; Hemmila, Marja; Sund, Jenni; Aijala, Mikko; Ehn, Mikael; Junninen, Heikki; Keronen, Petri; Petaja, Tuukka; Worsnop, Douglas R.; Kulmala, Markku; Hakola, Hannele (2014)
    Makkonen, U., Virkkula, A., Hellén, H., Hemmilä, M., Sund, J., Äijälä, M., Ehn, M., Junninen, H., Keronen, P., Petäjä, T., Worsnop, D. R., Kulmala, M. & Hakola,