Sediment metabolism in a transitional continental - marine area: The Albufera of Majorca (Balearic Islands, Spain)

1995 ◽  
Vol 46 (1) ◽  
pp. 45 ◽  
Author(s):  
P Lopez ◽  
M Vidal ◽  
X Lluch ◽  
JA Morgui
Keyword(s):  
Oxygen Consumption ◽  
Pore Water ◽  
Respiratory Quotient ◽  
Nutrient Dynamics ◽  
Anaerobic Respiration ◽  
Ammonium Phosphate ◽  
Nutrient Concentrations ◽  
Co2 Efflux ◽  
Marine Areas ◽  
Diffusive Fluxes

The concentrations of nutrients in sediment pore water and the fluxes of nutrients at the water-sediment interface were measured in a channel that joins continental and marine areas in the Albufera of Majorca in order to evaluate the role of sediments in the nutrient dynamics in this system. Upstream, surficial pore water presented lower values of Eh, which became negative in summer, whereas downstream Eh remained positive. Nutrient concentrations were especially high upstream, reaching 1000 mol L-1 of NH4 and 75 μmol L-1 of PO4 during summer. In summer, measured fluxes showed intense respiration upstream, with an oxygen consumption of 130 mg m-2 h-1 and a respiratory quotient near 4, which indicates dominance of anaerobic respiration. Total CO2 efflux and nutrient fluxes were also high, reaching 30.50 mmol m-2 h-1 for CO2, >2000 μmol m-2 h-1 for NH4 and 58 μmol m-2 h-1 for PO4. A substantial amount of the total CO2 efflux (14 mmol m-2 h-1) was due to calcium carbonate redissolution. Downstream, oxygen consumption, respiratory quotient and ammonium fluxes were lower (around 70 mg m-2 h-1, between 2 and 3, and <20 μmol m-2 h-1, respectively), which indicates a moderate rate of decomposition activity and suggests denitrification as the main respiratoy process. Differences between fluxes measured 'in situ' and those calculated from pore-water concentrations indicated non-diffusive fluxes upstream and suggest substantial denitrifying activity downstream. Extra keywords: benthic chambers, sediment fluxes, pore water, ammonium, phosphate.

NUTRIENT DYNAMICS IN EELGRASS (ZOSTERA MARINA) MEADOW AND THE VARIATION OF NUTRIENT CONTENTS OF EELGRASS

2017 ◽  
Author(s):  
Toshimasa Asahi ◽  
Toshimasa Asahi ◽  
Kazuhiko Ichimi ◽  
Kazuhiko Ichimi ◽  
Kuninao Tada ◽  
...  
Keyword(s):  
Water Column ◽  
Pore Water ◽  
Sediment Core ◽  
Zostera Marina ◽  
Nutrient Dynamics ◽  
Similar Rate ◽  
Nutrient Concentrations ◽  
Nutrient Source ◽  
Nutrient Contents ◽  
Seagrass Biomass

Nutrient dynamics in seagrass beds and nutrient demands of seagrass biomass are not clear, although nutrient uptake of seagrass has been experimentally studied in the laboratory. We conducted the field observations and the bottom sediment core incubations to estimate nutrient fluxes in the seagrass, Zostera marina meadow. DIN (nitrate, nitrite and ammonium) concentrations were always low particularly during the Z. marina growing season (from spring to summer), and water exchanges caused by tidal currents hardly supplied nutrient demand for Z. marina. Sediment pore water also supplied insufficient nutrients to Z. marina, because pore water had less volume than the water column, although DIN concentrations of pore water were 10-100 fold higher than those of the water column. Nutrient flux from sediment to water column estimated by the sediment core incubation experiments showed a similar rate with tidal water exchange. Thus, our results suggested that Z. marina adapted for low nutrient concentrations and each nutrient source in the Z. marina meadow slightly contributed but could not support Z. marina growth. We found that another nutrient source, for example, precipitation, supplied high DIN to the Z. marina meadow. After rainfall, the DIN concentration of seawater in the Z. marina meadow increased 2-5 times higher. Moreover, nitrogen content of eelgrass also increased 2-3 times higher during several days. Those results suggested that Z. marina was usually exposed to a low nutrient concentration but could uptake abundant nutrients from temporary nutrient supplies such as precipitation.

NUTRIENT DYNAMICS IN EELGRASS (ZOSTERA MARINA) MEADOW AND THE VARIATION OF NUTRIENT CONTENTS OF EELGRASS

2017 ◽  
Author(s):  
Toshimasa Asahi ◽  
Toshimasa Asahi ◽  
Kazuhiko Ichimi ◽  
Kazuhiko Ichimi ◽  
Kuninao Tada ◽  
...  
Keyword(s):  
Water Column ◽  
Pore Water ◽  
Sediment Core ◽  
Zostera Marina ◽  
Nutrient Dynamics ◽  
Similar Rate ◽  
Nutrient Concentrations ◽  
Nutrient Source ◽  
Nutrient Contents ◽  
Seagrass Biomass

Nutrient dynamics in seagrass beds and nutrient demands of seagrass biomass are not clear, although nutrient uptake of seagrass has been experimentally studied in the laboratory. We conducted the field observations and the bottom sediment core incubations to estimate nutrient fluxes in the seagrass, Zostera marina meadow. DIN (nitrate, nitrite and ammonium) concentrations were always low particularly during the Z. marina growing season (from spring to summer), and water exchanges caused by tidal currents hardly supplied nutrient demand for Z. marina. Sediment pore water also supplied insufficient nutrients to Z. marina, because pore water had less volume than the water column, although DIN concentrations of pore water were 10-100 fold higher than those of the water column. Nutrient flux from sediment to water column estimated by the sediment core incubation experiments showed a similar rate with tidal water exchange. Thus, our results suggested that Z. marina adapted for low nutrient concentrations and each nutrient source in the Z. marina meadow slightly contributed but could not support Z. marina growth. We found that another nutrient source, for example, precipitation, supplied high DIN to the Z. marina meadow. After rainfall, the DIN concentration of seawater in the Z. marina meadow increased 2-5 times higher. Moreover, nitrogen content of eelgrass also increased 2-3 times higher during several days. Those results suggested that Z. marina was usually exposed to a low nutrient concentration but could uptake abundant nutrients from temporary nutrient supplies such as precipitation.

Nutrient response to soil and litter metabolic activity in a transect across a seasonal wetland

2003 ◽  
Vol 54 (3) ◽  
pp. 243 ◽  
Author(s):  
S. Qiu ◽  
A. J. McComb ◽  
R. W. Bell ◽  
J. A. Davis
Keyword(s):  
Microbial Biomass ◽  
Microbial Activity ◽  
Nutrient Dynamics ◽  
Sand Dunes ◽  
Co2 Production ◽  
Nutrient Concentrations ◽  
Co2 Efflux ◽  
Wet Season ◽  
Surface Soils ◽  
Substrate Induced Respiration

Many wetlands in the interdunal depression of coastal sand dunes of the Swan Coastal Plain are surrounded by partially vegetated catchments. Although litter can be an important source of nutrients, little is known about litter related microbial activity in these catchments, especially its role in regulating nutrient concentrations in soils during the wet season. Heterotrophic microbial activity and phosphorus (P) dynamics were monitored before and after the onset of the wet season along transects from a vegetated catchment to the lakebed in Thomsons Lake, south-western Australia. Microbial activity was measured in the field as CO2 efflux (range from 47 to 176 mg CO2 m–2 h–1) and in the laboratory as substrate-induced-respiration (SIR; range from 11 to 133 μg g–1 h–1). Substrate-induced-respiration was positively correlated with soil organic content, and was concentrated in surface soils. In contrast, in the exposed lakebed most microbial biomass was below the surface, in the 10–30 cm depth zone. There were significant changes in nutrient dynamics in response to soil microbial activity. Before rain, P extracted by anion exchange membrane (PAEM) was well correlated with site litter and plant debris (r2 = 0.90, P�<�0.001), suggesting that PAEM in soils was litter-sourced. This relationship was modified during the wet season: there was an overall increase in microbial biomass P (PMB; from average 7.5 μg g–1 to 21.6 μg g–1), and a decrease in PAEM : PMB in surface soils. Along the study transect, the assimilation index PAEM : PMB declined towards the wetland, where soils were more silty and organic, and CO2 production was significantly higher. Our data suggest that heterotrophic microbial activity has a significant role in regulating P flux from catchment litter during the wet season, which would affect the mobility of litter-sourced P from catchment to the wetland.

scholarly journals Microbial Respiration and Enzyme Activity Downstream from a Phosphorus Source in the Everglades, Florida, USA

Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 696
Author(s):  
Sanku Dattamudi ◽  
Saoli Chanda ◽  
Leonard J. Scinto
Keyword(s):  
Nutrient Dynamics ◽  
Microbial Respiration ◽  
Organic Matter Content ◽  
Physicochemical Analysis ◽  
Matter Content ◽  
Enzyme Assays ◽  
Co2 Efflux ◽  
Soil Organic Matter Content ◽  
Phosphorus Source ◽  
P Distribution

Northeast Shark River Slough (NESS), lying at the northeastern perimeter of Everglades National Park (ENP), Florida, USA, has been subjected to years of hydrologic modifications. Construction of the Tamiami Trail (US 41) in 1928 connected the east and west coasts of SE Florida and essentially created a hydrological barrier to southern sheet flow into ENP. Recently, a series of bridges were constructed to elevate a portion of Tamiami Trail, allow more water to flow under the bridges, and attempt to restore the ecological balance in the NESS and ENP. This project was conducted to determine aspects of soil physiochemistry and microbial dynamics in the NESS. We evaluated microbial respiration and enzyme assays as indicators of nutrient dynamics in NESS soils. Soil cores were collected from sites at certain distances from the inflow (near canal, NC (0–150 m); midway, M (150–600 m); and far from canal, FC (600–1200 m)). Soil slurries were incubated and assayed for CO2 emission and β-glucoside (MUFC) or phosphatase (MUFP) activity in concert with physicochemical analysis. Significantly higher TP contents at NC (2.45 times) and M (1.52 times) sites than FC sites indicated an uneven P distribution downstream from the source canal. The highest soil organic matter content (84%) contents were observed at M sites, which was due to higher vegetation biomass observed at those sites. Consequently, CO2 efflux was greater at M sites (average 2.72 µmoles g dw−1 h−1) than the other two sites. We also found that amendments of glucose increased CO2 efflux from all soils, whereas the addition of phosphorus did not. The results indicate that microbial respiration downstream of inflows in the NESS is not limited by P, but more so by the availability of labile C.

Nutrient cycling differs between cropped soils with century-old and recently pyrolyzed biochar

2021 ◽  
Author(s):  
Victor Burgeon ◽  
Julien Fouché ◽  
Sarah Garré ◽  
Ramin Heidarian-Dehkordi ◽  
Gilles Colinet ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Soil Solution ◽  
Nutrient Dynamics ◽  
Chemical Properties ◽  
Crop Productivity ◽  
Nutrient Concentrations ◽  
Soil Productivity ◽  
Long Term Effects ◽  
Mitigation And Adaptation

&lt;p&gt;The amendment of biochar to soils is often considered for its potential as a climate change mitigation and adaptation tool through agriculture. Its presence in tropical agroecosystems has been reported to positively impact soil productivity whilst successfully storing C on the short&amp;#8201;and long-term. In temperate systems, recent research showed limited to no effect on productivity following recent biochar addition to soils. Its long-term effects on productivity and nutrient cycling have, however, been overlooked yet are essential before the use of biochar can be generalized.&lt;/p&gt;&lt;p&gt;Our study was set up in a conventionally cropped field, containing relict charcoal kiln sites used as a model for century old biochar (CoBC, ~220 years old). These sites were compared to soils amended with recently pyrolyzed biochar (YBC) and biochar free soils (REF) to study nutrient dynamics in the soil-water-plant system. Our research focused on soil chemical properties, crop nutrient uptake and soil solution nutrient concentrations. Crop plant samples were collected over three consecutive land occupations (chicory, winter wheat and a cover crop) and soil solutions gathered through the use of suctions cups inserted in different horizons of the studied Luvisol throughout the field.&lt;/p&gt;&lt;p&gt;Our results showed that YBC mainly influenced the soil solution composition whereas CoBC mainly impacted the total and plant available soil nutrient content. In soils with YBC, our results showed lower nitrate and potassium concentrations in subsoil horizons, suggesting a decreased leaching, and higher phosphate concentrations in topsoil horizons. With time and the oxidation of biochar particles, our results reported higher total soil N, available K and Ca in the topsoil horizon when compared to REF, whereas available P was significantly smaller. Although significant changes occurred in terms of plant available nutrient contents and soil solution nutrient concentrations, this did not transcend in variations in crop productivity between soils for neither of the studied crops. Overall, our study highlights that young or aged biochar behave as two distinct products in terms of nutrient cycling in soils. As such the sustainability of these soils differ and their management must therefore evolve with time.&lt;/p&gt;

GASEOUS METABOLISM IN PREMATURE INFANTS AT 32-34°C AMBIENT TEMPERATURE

PEDIATRICS ◽  
1964 ◽  
Vol 33 (1) ◽  
pp. 75-82
Author(s):  
Forrest H. Adams ◽  
Tetsuro Fujiwara ◽  
Robert Spears ◽  
Joan Hodgman
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Premature Infants ◽  
Rectal Temperature ◽  
Respiratory Quotient ◽  
Carbon Dioxide Production ◽  
Open Circuit ◽  
Co2 Production ◽  
O2 Consumption ◽  
Rate Of Increase

Thirty-four measurements of oxygen consumption, carbon dioxide production, respiratory quotient, and rectal temperature were made on 22 premature infants with ages ranging from 2½ hours to 18 days. The studies were conducted at 32-34°C utilizing an open circuit apparatus and a specially designed climatized chamber. Oxygen consumption and carbon dioxide production were lowest in the first 12 hours and increased thereafter. The rate of increase in O2 consumption was greater than that of CO2 production, with a consequent fall in respiratory quotient during the first 76 hours of life. A reverse relation of O2 consumption and CO2 production was found following the 4th day of life with a consequent rise in respiratory quotient. There was a close correlation between O2 consumption and rectal temperature regardless of age. A respiratory quotient below the value of 0.707 for fat metabolism was observed in 7 premature infants with ages ranging from 24 to 76 hours.

Nutrient distribution in the Bosphorus and surrounding areas

2002 ◽  
Vol 46 (8) ◽  
pp. 59-66 ◽  
Author(s):  
E. Okuş ◽  
A. Aslan-Yilmaz ◽  
A. Yüksek ◽  
S. Taş ◽  
V. Tüfekçi
Keyword(s):  
Chlorophyll A ◽  
Black Sea ◽  
Nutrient Dynamics ◽  
Lower Layer ◽  
Water Quality Monitoring ◽  
Nutrient Concentrations ◽  
The Black Sea ◽  
Sea Of Marmara ◽  
Nutrient Distribution ◽  
Northwestern Shelf

As part of a five years monitoring project “Water Quality Monitoring of the Strait of Istanbul”, February-December 1999 nutrient dynamics of the Black Sea-the Sea of Marmara transect are studied to evaluate the effect of discharges given by deep disposals. Through a one-year study, upper layer nutrient concentrations were generally under the effect of northwestern-shelf Black Sea originated waters. This effect was strictly observed in July, when the upper layer flow was the thickest. On the other hand, partly in November but especially in December the northwestern-shelf Black Sea originated water flow was a minimum resulting in similar concentrations in both layers. Nutrient fluctuations also affected the chlorophyll a and POC concentrations as parameters of productivity. The nutrient concentrations decreased with the effect of spring bloom and highest chlorophyll a values were detected in November at Strait stations that did not match to the Sea of Marmara values. This fact represents the time-scale difference between the Black Sea and the Sea of Marmara. On the contrary, high nutrient concentrations in the lower layer (especially inorganic phosphate), and therefore low N:P ratios reflect the effect of deep discharge. Vertical mixing caused by meteorological conditions of the shallow station (M3) under the effect of surface discharges resulted in homogenous distribution of nutrients. Nutrient concentrations of the stations affected by deep discharge showed that the two-layer stratification of the system did not permit the discharge mix to the upper layer.

scholarly journals Nickel Toxicity Induced Changes in Nutrient Dynamics and Antioxidant Profiling in Two Maize (Zea mays L.) Hybrids

Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 5 ◽  
Author(s):  
Muhammad Amjad ◽  
Hasan Raza ◽  
Behzad Murtaza ◽  
Ghulam Abbas ◽  
Muhammad Imran ◽  
...  
Keyword(s):  
Nutrient Solution ◽  
Elevated Level ◽  
Nutrient Dynamics ◽  
Zea Mays L ◽  
Nutrient Concentrations ◽  
Nickel Toxicity ◽  
Maize Hybrid ◽  
Maize Hybrids ◽  
Growth Physiology ◽  
Induced Changes

Nickel (Ni) is among the essential micronutrient heavy metals utilized by plants. However, an elevated level of Ni causes serious concerns for plants’ physiology and their survival. This study evaluated the mechanisms influencing the growth, physiology, and nutrient dynamics in two commercial maize hybrids (Syngenta and Pioneer) exposed to Ni treatments in hydroponics nutrient solution (NS). Seedlings were raised in plastic trays with quartz sand, and subsequently transferred to Hoagland’s NS at the two leaves stage. After three days of transplantation, Ni levels of 0, 20, and 40 mg L−1 were maintained in the nutrient solution. After 30 days of Ni treatments, seedlings were harvested and different growth, physiological, and nutrient concentrations were determined. The results showed that with increasing Ni concentration, the growth of maize hybrids was significantly reduced, and the maize hybrid, Pioneer, showed significantly higher growth than that of Syngenta at all levels of Ni. Higher growth in Pioneer is ascribed to elevated levels of antioxidant enzymes (SOD, CAT, GR, APX, and POX), lower damage to cellular membranes (i.e., higher MSI and lower MDA), and higher tissue nutrient concentrations (N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu). Furthermore, the maize hybrids showed a difference in nutrient translocation from root to shoot which could be one of the factors responsible for differential response of these hybrids against Ni treatments.

scholarly journals A Single Dose of Goji Berries Does Not Affect Postprandial Energy Expenditure and Substrate Oxidation in Healthy, Overweight Men

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
José J. van den Driessche ◽  
Jogchum Plat ◽  
Guy Plasqui ◽  
Ronald P. Mensink
Keyword(s):  
Oxygen Consumption ◽  
Single Dose ◽  
Glucose Metabolism ◽  
Energy Expenditure ◽  
Respiratory Quotient ◽  
Substrate Oxidation ◽  
Caloric Content ◽  
Lycium Barbarum ◽  
Meal Intake ◽  
Postprandial Energy Expenditure

Background and Aim. Increasing energy expenditure is an effective strategy for the prevention of obesity. In this respect, Lycium barbarum (goji berry) is of interest, as it has been shown to increase postprandial oxygen consumption. Although this suggests that energy expenditure was also increased, energy expenditure and substrate oxidation can only be assessed accurately when both oxygen consumption and carbon dioxide production are measured. We therefore investigated the effects of a single dose of Lycium barbarum fruit on postprandial energy expenditure and substrate oxidation in a randomized, double-blind crossover trial. In addition, markers of lipid and glucose metabolism were measured. Methods. Seventeen healthy, overweight men received in a random order a meal containing 25 grams of dried Lycium barbarum fruit or a control meal matched for caloric content and macronutrient composition. Energy expenditure and the respiratory quotient were determined using indirect calorimetry before and up to 4 hours after meal intake. Blood was sampled before and after meal intake at regular intervals for analyses of plasma glucose, serum triacylglycerol, and free fatty acid concentrations. Results. Energy expenditure significantly increased after the Lycium barbarum and control meal, but no differences were found between the meals (p=0.217). Postprandial changes in respiratory quotient (p=0.719) and concentrations of glucose (p=0.663), triacylglycerol (p=0.391), and free fatty acids (p=0.287) were also not affected by Lycium barbarum intake. Conclusions. A single dose of Lycium barbarum does not affect postprandial energy expenditure, substrate oxidation, and markers for lipid and glucose metabolism in healthy, overweight men.

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