Short term nitrogen dynamics in a small Brazilian wetland (Lago Infernão, São Paulo)

ABSTRACTWe have studied a number of related processes of the nitrogen cycle in a Brazilian floodplain lake to identify the major pools and pathways over a short time period. The study was centred on the littoral zone dominated by the floating plantEichhornia azurea, which has a large epiphyte algal community of which heterocystous cyanobacteria were the major components. The water column was continuously undersaturated with oxygen although some elevated values (to 60% saturation) were recorded in the macrophyte beds in the afternoon. Marked diel temperature changes were documented. NH4-N dominated the dissolved N component in the water with maximal values (60 mg m−3) at lowest O2, concentrations early in the morning. Nitrogen fixation (acetylene reduction) of the epiphyte community showed marked diel changes with daily values of 5 mg N fixed m−2day−1(based on 3:1 C2H4:N2ratio). Macrophyte NH4-N uptake rates (in situincubations) were 93 mg N m−2day−1. The activities of nitrifying bacteria could not be detected with the nitrapyrin block on dark CO2fixation but denitrification (acetylene block technique) was recorded in the sediments when enhanced with NO-3. The major pathways of aquatic nitrogen involved macrophyte uptake and sediment release of NH4-N.

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Effect of incubation time and substrate concentration on N-uptake rates by phytoplankton in the Bay of Bengal

Biogeosciences Discussions ◽

10.5194/bgd-2-1331-2005 ◽

2005 ◽

Vol 2 (5) ◽

pp. 1331-1352

Author(s):

S. Kumar ◽

R. Ramesh ◽

S. Sardesai ◽

M. S. Sheshshayee

Keyword(s):

Incubation Time ◽

Uptake Rate ◽

Nitrate Uptake ◽

N Uptake ◽

Marine Phytoplankton ◽

Total Production ◽

New Production ◽

Urea Uptake ◽

Uptake Rates

Abstract. We report here the results of three experiments, which are slight variations of the 15N method (JGOFS protocol) for determination of new production. The first two test the effect of (i) duration of incubation time and (ii) concentration of tracer added on the uptake rates of various N-species (nitrate, ammonium and urea) by marine phytoplankton; while the third compares in situ and deck incubations from dawn to dusk. Results indicate that nitrate uptake can be underestimated by experiments where incubation times shorter than 4h or when more than 10% of the ambient concentration of nitrate is added prior to incubation. The f-ratio increases from 0.28 to 0.42 when the incubation time increases from two to four hours. This may be due to the observed increase in the uptake rate of nitrate and decrease in the urea uptake rate. Unlike ammonium [y{=}2.07x{-}0.002\\, (r2=0.55)] and urea uptakes [y{=}1.88x{+}0.004 (r2=0.88)], the nitrate uptake decreases as the concentration of the substrate (x) increases, showing a negative correlation [y{=}-0.76x+0.05 (r2=0.86)], possibly due to production of glutamine, which might suppress nitrate uptake. This leads to decline in the f-ratio from 0.47 to 0.10, when concentration of tracer varies from 0.01 to 0.04μ M. The column integrated total productions are 519 mg C m-2 d-1 and 251 mg C m-2 d-1 for in situ and deck incubations, respectively. The 14C based production at the same location is ~200 mg C m-2 d-1, which is in closer agreement to the 15N based total production measured by deck incubation.

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First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas

10.5194/bg-2018-76 ◽

2018 ◽

Author(s):

Bhavya P. Sadanandan ◽

Jang Han Lee ◽

Ho Won Lee ◽

Jae Joong Kaang ◽

Jae Hyung Lee ◽

...

Keyword(s):

Sea Ice ◽

Nitrogen Uptake ◽

N Uptake ◽

Total Carbon ◽

The Arctic ◽

Carbon And Nitrogen ◽

Uptake Rates ◽

Wide Range ◽

Small Phytoplankton

Abstract. Carbon and nitrogen uptake rates by small phytoplankton (0.7–5 μm) in the Kara, Laptev, and East Siberian seas in the Arctic Ocean were quantified using in situ isotope labelling experiments for the first time as part of the NABOS (Nansen and Amundsen Basins Observational System) program during August 21 to September 22, 2013. The depth integrated C, NO3−, and NH4+ uptake rates by small phytoplankton showed a wide range from 0.54 to 15.96 mg C m−2 h−1, 0.05 to 1.02 and 0.11 to 3.73 mg N m−2 h−1, respectively. The contributions of small phytoplankton towards the total C, NO3−, and NH4+ was varied from 24 to 89 %, 32 to 89 %, and 28 to 89 %, respectively. The turnover times for NO3− and NH4+ by small phytoplankton during the present study point towards the longer residence times (years) of the nutrients in the deeper waters, particularly for NO3−. Relatively, higher C and N uptake rates by small phytoplankton obtained during the present study at locations with less sea ice concentrations points towards the possibility of small phytoplankton thrive under sea ice retreat under warming conditions. The high contributions of small phytoplankton towards the total carbon and nitrogen uptake rates suggest capability of small size autotrophs to withstand in the adverse hydrographic conditions introduced by climate change.

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First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas

Biogeosciences ◽

10.5194/bg-15-5503-2018 ◽

2018 ◽

Vol 15 (18) ◽

pp. 5503-5517 ◽

Cited By ~ 6

Author(s):

P. Sadanandan Bhavya ◽

Jang Han Lee ◽

Ho Won Lee ◽

Jae Joong Kang ◽

Jae Hyung Lee ◽

...

Keyword(s):

Sea Ice ◽

Nitrogen Uptake ◽

Isotope Labeling ◽

N Uptake ◽

The Arctic ◽

Carbon And Nitrogen ◽

Uptake Rates ◽

Small Phytoplankton ◽

C And N

Abstract. Carbon and nitrogen uptake rates by small phytoplankton (0.7–5 µm) in the Kara, Laptev, and East Siberian seas in the Arctic Ocean were quantified using in situ isotope labeling experiments; this research, which was novel and part of the NABOS (Nansen and Amundsen Basins Observational System) program, took place from 21 August to 22 September 2013. The depth-integrated carbon (C), nitrate (NO3-), and ammonium (NH4+) uptake rates by small phytoplankton ranged from 0.54 to 15.96 mg C m−2 h−1, 0.05 to 1.02 mg C m−2 h−1, and 0.11 to 3.73 mg N m−2 h−1, respectively. The contributions of small phytoplankton towards the total C, NO3-, and NH4+ varied from 25 % to 89 %, 31 % to 89 %, and 28 % to 91 %, respectively. The turnover times for NO3- and NH4+ by small phytoplankton found in the present study indicate the longer residence times (years) of the nutrients in the deeper waters, particularly for NO3-. Additionally, the relatively higher C and N uptake rates by small phytoplankton obtained in the present study from locations with less sea ice concentration indicate the possibility that small phytoplankton thrive under the retreat of sea ice as a result of warming conditions. The high contributions of small phytoplankton to the total C and N uptake rates suggest the capability of small autotrophs to withstand the adverse hydrographic conditions introduced by climate change.

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Sugar maple seedling carbon assimilation at the northern limit of its range: the importance of seasonal light

Canadian Journal of Forest Research ◽

10.1139/x09-196 ◽

2010 ◽

Vol 40 (2) ◽

pp. 385-393 ◽

Cited By ~ 19

Author(s):

Matthew C. Kwit ◽

Lesley S. Rigg ◽

David Goldblum

Keyword(s):

Acer Saccharum ◽

Sugar Maple ◽

Carbon Assimilation ◽

Frost Damage ◽

Carbon Gain ◽

Time Period ◽

History Of ◽

Short Time ◽

Seedling Leaf

Using in situ light curves and understory seasonal light measurements the importance of canopy avoidance was evaluated for a population of sugar maple ( Acer saccharum Marsh.) seedlings living at the boreal ecotone in Lake Superior Provincial Park, Ontario, Canada. At higher latitudes, the time period associated with canopy avoidance is shorter and occurs at cooler temperatures, increasing the risk of frost damage. In 2008, leaf-out began 5 days prior to the last frost of the season. By modeling the potential carbon gain of seedlings, it is clear that the short time period prior to canopy leaf-out still contributes a disproportionate amount of carbon to the overall budget of seedlings. Of the total seasonal carbon gain, 80.6% was assimilated in the initial 15 days following sugar maple seedling leaf-out. Based on our model, by leafing out only 6 days earlier than the average seedling leaf-out date, ∼200% more carbon could be assimilated during the course of the growing season. Vegetation phenology is cued by climatic triggers — as climate changes so too will phenological responses. These mechanisms add to the overall carbon budget of seedlings; recognizing these mechanisms is essential to thoroughly understand the natural history of this species.

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Different Relationships of Fine Root Traits With Root Ammonium and Nitrate Uptake Rates in Conifer Forests

10.21203/rs.3.rs-1091934/v1 ◽

2021 ◽

Author(s):

Takumi Ito ◽

Ayumi Tanaka-Oda ◽

Taiga Masumoto ◽

Maiko Akatsuki ◽

Naoki Makita

Keyword(s):

Morphological Traits ◽

Nitrate Uptake ◽

Fine Root ◽

N Uptake ◽

Root Traits ◽

Inorganic N ◽

Uptake Rates ◽

Relationship Of ◽

The Relationship

Abstract Purpose: Nitrogen (N) uptake by fine roots of trees is important for understanding the root physiological function in forest ecosystems, but a direct investigation of in situ rate of ammonium and nitrate uptake is limited. Thus, we aimed to clarify the inorganic N uptake rates among tree species and to determine the factors controlling N uptake through relationships with fine root traits in cool temperate forests.Methods: Using a solution depletion method for measuring N uptake, we observed the relationship of N uptake rate in the form of NH4+ and NO3– by an intact root system with root morphological traits, such as root diameter, specific root length (SRL), and root tissue density (RTD), and chemical traits, including root nitrogen (N) content. Results: The coniferous roots in this study preferred NH4+ form more than NO3– form. Across species, there were significant relationships between NH4+ uptake and diameter, SRL, and RTD, while these were significant only for RTD in NO3– form. Relationships between N uptake rates and root morphological traits differed between NH4+ and NO3–. Conclusions: We found that the relationship of inorganic N uptake with the morphological traits depends on the characteristics of the N form adsorbed through soil and tree N assimilation efficiency. An approach on the relationships of in situ N uptake with root traits will provide a breakthrough in our understanding of the root physiological function and the prediction of fundamental N acquisition strategies.

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World Economy: Prospects and Barriers for Recovery

Voprosy Ekonomiki ◽

10.32609/0042-8736-2012-12-61-83 ◽

2012 ◽

pp. 61-83 ◽

Cited By ~ 1

Author(s):

M. Ershov

Keyword(s):

World Economy ◽

Western World ◽

Short Time Period ◽

Market Segments ◽

Junk Bonds ◽

The Past ◽

Time Period ◽

The Us ◽

Global Liquidity ◽

Short Time

According to the latest forecasts, it will take 10 years for the world economy to get back to “decent shape”. Some more critical estimates suggest that the whole western world will have a “colossal mess” within the next 5–10 years. Regulators of some major countries significantly and over a short time‑period changed their forecasts for the worse which means that uncertainty in the outlook for the future persists. Indeed, the intensive anti‑crisis measures have reduced the severity of the past problems, however the problems themselves have not disappeared. Moreover, some of them have become more intense — the eurocrisis, excessive debts, global liquidity glut against the backdrop of its deficit in some of market segments. As was the case prior to the crisis, derivatives and high‑risk operations with “junk” bonds grow; budget problems — “fiscal cliff” in the US — and other problems worsen. All of the above forces the regulators to take unprecedented (in their scope and nature) steps. Will they be able to tackle the problems which emerge?

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Effect of short-term use of oral contraceptive pills on intraocular pressure

Pakistan Journal of Ophthalmology ◽

10.36351/pjo.v35i3.871 ◽

2020 ◽

Vol 35 (3) ◽

Author(s):

Tayyaba Gul Malik ◽

Hina Nadeem ◽

Eiman Ayesha ◽

Rabail Alam

Keyword(s):

Oral Contraceptive ◽

Childbearing Age ◽

Short Term ◽

Oral Contraceptive Pills ◽

Contraceptive Pills ◽

Time Period ◽

Significant Difference ◽

Group A ◽

Group B ◽

Short Time

Objective: To study the effect of short-term use of oral contraceptive pills on intra-ocular pressures of women of childbearing age. Methods: It was a comparative observational study, conducted at Arif memorial teaching hospital and Allied hospital Faisalabad for a period of six months. Hundred female subjects were divided into two groups of 50 each. Group A, included females, who had been taking oral contraceptive pills (OCP) for more than 6 months and less than 36 months. Group B, included 50 age-matched controls, who had never used OCP. Ophthalmic and systemic history was taken. Careful Slit lamp examination was performed and intraocular pressures (IOP) were measured using Goldman Applanation tonometer. Fundus examination was done to rule out any posterior segment disease. After collection of data, we analyzed and compared the intra ocular pressures between the two groups by using ANOVA in SPSS version 21. Results: Average duration of using OCP was 14.9 months. There was no significant difference of Cup to Disc ratios between the two groups (p= 0.109). However, significant difference was noted between the IOP of OCP group and controls. (p=0.000). Conclusion: OCP significantly increase IOP even when used for short time period.

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Rapid quantification and in situ detection of nitrifying bacteria in biofilms by monoclonal antibody method

Water Science & Technology ◽

10.2166/wst.2000.0459 ◽

2000 ◽

Vol 41 (4-5) ◽

pp. 301-308 ◽

Cited By ~ 1

Author(s):

N. Noda ◽

H. Ikuta ◽

Y. Ebie ◽

A. Hirata ◽

S. Tsuneda ◽

...

Keyword(s):

Monoclonal Antibody ◽

Monoclonal Antibodies ◽

Fluorescent Antibody ◽

Nitrifying Bacteria ◽

Fluorescent Antibody Technique ◽

Antibody Technique ◽

Antibody Method ◽

In Situ Detection ◽

Rapid Quantification

Fluorescent antibody technique by the monoclonal antibody method is very useful and helpful for the rapid quantification and in situ detection of the specific bacteria like nitrifiers in a mixed baxterial habitat such as a biofilm. In this study, twelve monoclonal antibodies against Nitrosomonas europaea (IFO14298) and sixteen against Nitrobacter winogradskyi (IFO14297) were raised from splenocytes of mice (BALB/c). It was found that these antibodies exhibited little cross reactivity against various kinds of heterotrophic bacteria. The direct cell count method using monoclonal antibodies could exactly detect and rapidly quantify N. europaea and N. winogradskyi. Moreover, the distribution of N. europaea and N. winogradskyi in a biofilm could be examined by in situ fluorescent antibody technique. It was shown that most of N. winogradskyi existed near the surface part and most of N. europaea existed at the inner part of the polyethylene glycol (PEG) gel pellet, which had entrapped activated sludge and used in a landfill leachate treatment reactor. It was suggested that this monoclonal antibody method was utilized for estimating and controlling the population of nitrifying bacteria as a quick and favorable tool.

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Political ideology and vaccination willingness: implications for policy design

Policy Sciences ◽

10.1007/s11077-021-09428-0 ◽

2021 ◽

Author(s):

Marc Debus ◽

Jale Tosun

Keyword(s):

Side Effects ◽

Political Ideology ◽

Policy Design ◽

Public Support ◽

Individual Freedom ◽

Short Time Period ◽

Successful Development ◽

Individual Level ◽

Time Period ◽

Short Time

AbstractThe COVID-19 pandemic has forced governments to impose major restrictions on individual freedom in order to stop the spread of the virus. With the successful development of a vaccine, these restrictions are likely to become obsolete—on the condition that people get vaccinated. However, parts of the population have reservations against vaccination. While this is not a recent phenomenon, it might prove a critical one in the context of current attempts to manage the COVID-19 pandemic. Consequently, the task of designing policies suitable for attaining high levels of vaccination deserves enhanced attention. In this study, we use data from the Eurobarometer survey fielded in March 2019. They show that 39% of Europeans consider vaccines to cause the diseases which they should protect against, that 50% believe vaccines have serious side effects, that 32% think that vaccines weaken the immune system, and that 10% do not believe vaccines are tested rigorously before authorization. We find that—even when controlling for important individual-level factors—ideological extremism on both ends of the spectrum explains skepticism of vaccination. We conclude that policymakers must either politicize the issue or form broad alliances among parties and societal groups in order to increase trust in and public support for the vaccines in general and for vaccines against COVID-19 in particular, since the latter were developed in a very short time period and resulted—in particular in case of the AstraZeneca vaccine—in reservations because of the effectiveness and side effects of the new vaccines.

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Platypnoea–orthodeoxia syndrome induced by short-term weight loss: a case series

European Heart Journal - Case Reports ◽

10.1093/ehjcr/ytaa498 ◽

2020 ◽

Author(s):

Yudai Tamura ◽

Tomohiro Sakamoto

Keyword(s):

Weight Loss ◽

Septal Defect ◽

Case Series ◽

Transoesophageal Echocardiography ◽

Sitting Position ◽

Short Time Period ◽

Time Period ◽

Uncommon Condition ◽

The Right ◽

Short Time

Abstract Background Platypnoea–orthodeoxia syndrome (POS) is an uncommon condition characterized by dyspnoea and arterial desaturation in the standing or sitting position that improves in the supine position. Case summary We report two cases of POS caused by an atrial septal defect (ASD) and a patent foramen ovale (PFO). Both cases reported a recent decrease in body weight of more than 10 kg in a short time period. Transoesophageal echocardiography (TOE) with agitated saline bubble study revealed and a large amount of contrast bubble through the ASD (Patient 1) or the PFO (Patient 2) from the right atrium to the left atrium in the sitting position. Both patients were diagnosed by the finding of positional dyspnoea and the results of TOE using agitated saline bubble contrast. Discussion Taken together, their presentations suggest that weight loss in a short time period could be a pathogenic factor for POS.

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