Estimating pelagic primary production in lakes: Comparison of 14 C incubation and free‐water O 2 approaches

2021 ◽  
Author(s):  
Noah R. Lottig ◽  
Joseph S. Phillips ◽  
Ryan D. Batt ◽  
Facundo Scordo ◽  
Tanner J. Williamson ◽  
...  
Keyword(s):  
Primary Production ◽  
Free Water

Gross primary production and respiration differences among littoral and pelagic habitats in northern Wisconsin lakes

2006 ◽  
Vol 63 (5) ◽  
pp. 1130-1141 ◽  
Author(s):  
George H Lauster ◽  
Paul C Hanson ◽  
Timothy K Kratz
Keyword(s):  
Primary Production ◽  
Surface Waters ◽  
Gross Primary Production ◽  
Free Water ◽  
Lake Metabolism ◽  
Trophic Conditions ◽  
Littoral Zones ◽  
Ecosystem Production ◽  
Littoral Area ◽  
Littoral Habitats

Net ecosystem production (NEP) trends among lakes have been ascribed to differences in nutrient and allochthonous carbon inputs, but little is known on how different habitats within lakes contribute to these trends. We sampled pelagic and littoral surface waters using sonde (i.e., free-water) and bottle methods concurrently in lakes spanning a range of trophic conditions. We considered whether the typically higher metabolism estimates found with sonde methods are due to contributions from littoral habitats not reflected by bottle estimates. We sought the source of littoral contributions by selecting sites with maximum differences in macrophyte abundance. Sonde estimates for pelagic primary production and respiration were two–three times greater than bottle estimates. Sonde/bottle ratios were higher in productive lakes and lakes with more littoral area. Bottle estimates were similar among all sites, and sonde estimates in macrophyte-poor sites were similar to pelagic sondes. However, sonde estimates in macrophyte-rich areas were four–nine times greater than bottle estimates. Results suggest littoral zones increase whole-lake NEP in eutrophic systems, whereas the Sphagnum mat surrounding dystrophic lakes decreases NEP. Non-planktonic organisms associated with macrophytes provide important littoral contributions to whole-lake metabolism and to understanding NEP trends among lakes.

Microwave resonance method for measuring microliter volumes of free moisture in aviation fuels

2020 ◽  
pp. 49-56
Author(s):  
Vitaly V. Volkov ◽  
Michael A. Suslin ◽  
Jamil U. Dumbolov
Keyword(s):  
Solid Surface ◽  
Free Water ◽  
Resonance Method ◽  
Cavity Resonator ◽  
Maximum Error ◽  
Aviation Fuel ◽  
Fuel Quality ◽  
Microwave Resonance ◽  
Free Moisture ◽  
Microwave Losses

One of the conditions for ensuring the safety of air transport operation is the quality of aviation fuel refueled in aircraft. Fuel quality control is a multi-parameter task that includes monitoring the free moisture content. Regulatory documents establish the content of free water no more than 0.0015% by weight. It is developed a direct electrometric microwave resonance method for controlling free moisture in aviation fuels, which consists in changing the shape of the water drops by pressing them on a solid surface inside a cylindrical cavity resonator. This can dramatically increase dielectric losses. Analytical and experimental analysis of the proposed method is carried out. The control range from 0,5 to 30 μl of absolute volume of moisture in aviation fuels with a maximum error of not morethan 25 % is justified. The sensitivity of the proposed method for monitoring microwave losses in free moisture drops transformed into a thin layer by pressing is an order of magnitude greater than the sensitivity of the method for monitoring microwave losses in moisture drops on a solid surface in a resonator. The proposed method can be used as a basis for the development of devices for monitoring the free moisture of aviation fuels in the conditions of the airfield and laboratory. The direction of development of the method is shown.

PRESENT AND FUTURE PROSPECTS FOR FORESTRY IN THE CENTRAL PUMICE REGION

1971 ◽  
pp. 14-17
Author(s):  
J. Ure
Keyword(s):  
New Zealand ◽  
Primary Production ◽  
Future Prospects ◽  
Export Markets ◽  
Local Conditions

The region contains half the area of exotic forest in New Zealand and the major industries dependent thereon. Both are expanding rapidly to meet promising export markets. Local conditions are particularly favourable for this form of primary production and continued expansion is expected.

Primary Production of Phytoepiphyton in Water Bodies of Kiev

2008 ◽  
Vol 44 (4) ◽  
pp. 35-41 ◽  
Author(s):  
O. A. Sosnovskaya ◽  
P. D. Klochenko ◽  
G. V. Kharchenko
Keyword(s):  
Primary Production ◽  
Water Bodies
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