Nitrogen and phosphorus dynamics in a large river estimated by an in situ Lagrangian tracking approach

2017 ◽  
Vol 62 (12) ◽  
pp. 1997-2007 ◽  
Author(s):  
Yuta Kobayashi ◽  
Tomoya Iwata
Keyword(s):  
Large River ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Dynamics ◽  
Lagrangian Tracking ◽  
Lagrangian Tracking Approach

Impact of migratory snow geese on nitrogen and phosphorus dynamics in a freshwater reservoir

2005 ◽  
Vol 50 (5) ◽  
pp. 882-890 ◽  
Author(s):  
MARK H. OLSON ◽  
MELISSA M. HAGE ◽  
MARK D. BINKLEY ◽  
JAMES R. BINDER
Keyword(s):  
Nitrogen And Phosphorus ◽  
Phosphorus Dynamics ◽  
Snow Geese ◽  
Freshwater Reservoir

scholarly journals River Discharge Estimation based on Satellite Water Extent and Topography: An Application over the Amazon

2019 ◽  
Vol 20 (9) ◽  
pp. 1851-1866 ◽  
Author(s):  
Dinh Thi Lan Anh ◽  
Filipe Aires
Keyword(s):  
River Discharge ◽  
Amazon Basin ◽  
Water Cycle ◽  
Large River ◽  
Water Volume ◽  
Discharge Estimation ◽  
Three Rivers ◽  
Storage Change

Abstract River discharge (RD) estimates are necessary for many applications, including water management, flood risk, and water cycle studies. Satellite-derived long-term GIEMS-D3 surface water extent (SWE) maps and HydroSHEDS data, at 90-m resolution, are here used to estimate several hydrological quantities at a monthly time scale over a few selected locations within the Amazon basin. Two methods are first presented to derive the water level (WL): the “hypsometric curve” and the “histogram cutoff” approaches at an 18 km × 18 km resolution. The obtained WL values are interpolated over the whole water mask using a bilinear interpolation. The two methods give similar results and validation with altimetry is satisfactory, with a correlation ranging from 0.72 to 0.89 in the seven considered stations over three rivers (i.e., Wingu, Negro, and Solimoes Rivers). River width (RW) and water volume change (WVC) are also estimated. WVC is evaluated with GRACE total water storage change, and correlations range from 0.77 to 0.88. A neural network (NN) statistical model is then used to estimate the RD based on four predictors (SWE, WL, WVC, and RW) and on in situ RD measurements. Results compare well to in situ measurements with a correlation of about 0.97 for the raw data (and 0.84 for the anomalies). The presented methodologies show the potential of historical satellite data (the combination of SWE with topography) to help estimate RD. Our study focuses here on a large river in the Amazon basin at a monthly scale; additional analyses would be required for other rivers, including smaller ones, in different environments, and at higher temporal scale.

scholarly journals Chemical Element Concentrations of Cycad Leaves: Do We Know Enough?

Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 85 ◽  
Author(s):  
Benjamin E. Deloso ◽  
Murukesan V. Krishnapillai ◽  
Ulysses F. Ferreras ◽  
Anders J. Lindström ◽  
Michael Calonje ◽  
...  
Keyword(s):  
Root Zone ◽  
Chemical Elements ◽  
Incident Light ◽  
Leaf Age ◽  
Influential Factors ◽  
Nutrient Concentrations ◽  
Future Research ◽  
Nitrogen And Phosphorus ◽  
Element Concentrations

The literature containing which chemical elements are found in cycad leaves was reviewed to determine the range in values of concentrations reported for essential and beneficial elements. We found 46 of the 358 described cycad species had at least one element reported to date. The only genus that was missing from the data was Microcycas. Many of the species reports contained concentrations of one to several macronutrients and no other elements. The cycad leaves contained greater nitrogen and phosphorus concentrations than the reported means for plants throughout the world. Magnesium was identified as the macronutrient that has been least studied. Only 14 of the species were represented by data from in situ locations, with most of the data obtained from managed plants in botanic gardens. Leaf element concentrations were influenced by biotic factors such as plant size, leaf age, and leaflet position on the rachis. Leaf element concentrations were influenced by environmental factors such as incident light and soil nutrient concentrations within the root zone. These influential factors were missing from many of the reports, rendering the results ambiguous and comparisons among studies difficult. Future research should include the addition of more taxa, more in situ locations, the influence of season, and the influence of herbivory to more fully understand leaf nutrition for cycads.

Laboratory and in situ grazing rates of large river rotifers and their contribution to community grazing rates

1998 ◽  
Vol 26 (4) ◽  
pp. 1935-1935
Author(s):  
V. Gosselain ◽  
C. Joaquim-Justo ◽  
L. Viroux ◽  
M. Mena ◽  
M. Metens ◽  
...  
Keyword(s):  
Large River ◽  
Community Grazing

Importance of flood zones for nitrogen and phosphorus dynamics in the Danube Delta

Hydrobiologia ◽  
1993 ◽  
Vol 251 (1-3) ◽  
pp. 143-148 ◽  
Author(s):  
Sergiu Cristofor ◽  
Angheluta Vadineanu ◽  
Gheorghe Ignat
Keyword(s):  
Danube Delta ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Dynamics
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