Energy budget for a stream population of the freshwater clam, Sphaerium striatinum Lamarck (Bivalvia: Pisidiidae)

1984 ◽  
Vol 62 (12) ◽  
pp. 2410-2417 ◽  
Author(s):  
Daniel J. Hornbach ◽  
Thomas E. Wissing ◽  
Albert J. Burky
Keyword(s):  
Energy Budget ◽  
Standing Crop ◽  
Production Efficiency ◽  
Reproductive Effort ◽  
Energy Partitioning ◽  
Minimum Size ◽  
Energy Needs ◽  
Annual Productivity ◽  
Deposit Feeding ◽  
Growth And Reproduction

An annual energy budget was constructed for a stream population of Sphaerium striatinum. The annual productivity (P) was 2.79 g C∙m−2∙year−1 and the average standing crop biomass (B) was 0.58 g C∙m−2; the resulting annual P:B ratio of 4.58 is below that expected for a bivoltine animal. The low value for reproductive effort (Re:P = 16.1%) may partially be attributed to the ovoviviparous, iteroparous nature of this population. A strategy of partitioning a large proportion of production to growth (G:P = 83.9%) may insure a high probability of attaining the minimum size necessary for reproduction. Production accounts for 44% of assimilation (A) with 56% of A lost through respiration. The net production efficiency (P:A = 44%) is high and indicates that this population is efficient in partitioning energy to growth and reproduction. The population must consume (C) 10.57 g C∙m−2∙year−1 to meet its energy needs. Only 35% of this could be accounted for by filter feeding; the remainder may have come from deposit feeding. Comparisons of P, P:B, Re:P and P:A with published values for corbiculacean clams indicates that this population of S. striatinum is one of the most productive and efficient in its energy partitioning of populations studied to date.

Energy Flow and Secondary Production of the Amphipods Hyalella azteca and Crangonyx richmondensis occidentalis in Marion Lake, British Columbia

1971 ◽  
Vol 28 (5) ◽  
pp. 711-726 ◽  
Author(s):  
Jack A. Mathias
Keyword(s):  
Population Growth ◽  
Energy Flow ◽  
Standing Crop ◽  
Production Efficiency ◽  
Hyalella Azteca ◽  
Growth Efficiency ◽  
Ecological Efficiency ◽  
Net Production ◽  
Annual Basis ◽  
Predator System

The Hyalella azteca population in Marion Lake, B.C., assimilated and produced about three times as much energy as did the Crangonyx richmondensis occidentalis population from May 1966 to May 1967, but during the summer the energy flow of H. azteca was four times, and production was five times, that of C. r. occidentalis.Hyalella azteca was abundant at a depth of 1.0 m (mean summer standing crop, 1952 animals/m2), but was rare (75 animals/m2) at depths greater than 2.5 m. Growth, molting, respiration, and hence energy flow rates decreased with depth, due (in part) to lower ambient temperatures in deeper water. On an annual basis, a mean standing crop of 1.1 kcal/m2 of H. azteca assimilated 18.1 kcal/m2, respired 13.5 kcal/m2, and used 4.6 kcal/m2 in production of growth, molts, and eggs. Approximately two-thirds of the annual energy flow was completed between June and October. On an annual basis, the ecological efficiency of an H. azteca-predator system was in the range 2.5–12.5%, the net production efficiency was 25%, and the net population growth efficiency was 16%.The mean summer density of C. r. occidentalis remained constant with depth (about 283 animals/m2). Annual energy flow and production were not appreciably affected by lower temperatures in deeper water. On an annual basis, a mean standing crop of 0.7 kcal/m2 assimilated 6.5 kcal/m2, respired 5.2 kcal/m2, and used 1.4 kcal/m2 in production. Crangonyx r. occidentalis energy flow was fairly constant throughout the year. The ecological efficiency of a C. r. occidentalis-predator system was in the range 2–10.5%, the net production efficiency was 21%, and the population growth efficiency was 17% on an annual basis.

Patterns of growth and reproduction in a perennial tundra forb (Geum rossii): effects of clone area and neighborhood

1991 ◽  
Vol 69 (9) ◽  
pp. 1977-1983 ◽  
Author(s):  
Jeanne C. Chambers
Keyword(s):  
Spatial Distribution ◽  
Reproductive Effort ◽  
Pattern Analysis ◽  
Trade Off ◽  
Geometric Function ◽  
Site Characteristics ◽  
Mineral Soils ◽  
Clonal Species ◽  
Related Pattern ◽  
Growth And Reproduction

The relationships of clone area and neighborhood to ramet size, reproductive effort, and spatial distribution within Geum rossii clones were studied in an alpine ecosystem on the Beartooth Plateau, Montana. Clones growing on an early seral site in relative isolation were compared to clones on a late seral site within dense, heterogeneous neighborhoods. Individual clones of G. rossii required a minimum clone area of about 200 cm2 before maximum ramet size and reproductive effort were achieved. Mean ramet size and reproductive effort were fairly constant among clones larger than 200 cm2 on both the early and later seral sites. Within clones the size and reproductive effort of ramets were positively related. Pattern analysis revealed that ramets became more widely and irregularly spaced as clone area increased on the early seral site. This may have been a geometric function of an increase in the space required as clones aged and became larger. On the late seral site, clones were characterized by ramets that were widely and erratically spaced, that had low leaf numbers and mass, and that had low reproductive effort. For clones of comparable area on the early seral site, ramets were more closely and uniformly spaced, and leaf number, mass, and reproduction per ramet were higher. Conservative patterns of growth and reproduction make G. rossii well suited to dominate in dense, heterogeneous neighborhoods of late seral sites and to colonize mineral soils of early seral sites. Similar to other clonal species, site characteristics and the type of neighborhood determine the trade-off between the physical occupation of space and the allocation to ramet growth and reproduction in G. rossii. Key words: Geum rossii, alpine, reproductive effort, growth, clone area, pattern analysis, succession, neighborhood.

Differences in plant size and flower production between hermaphrodites and females of two gynodioecious Chionographis (Liliaceae)

1996 ◽  
Vol 74 (1) ◽  
pp. 150-153 ◽  
Author(s):  
Masayuki Maki
Keyword(s):  
Frequency Distribution ◽  
Reproductive Effort ◽  
Plant Size ◽  
Flowering Plants ◽  
Size Class ◽  
Minimum Size ◽  
Dioecious Species ◽  
Flower Production ◽  
Flowering Season ◽  
Secondary Sex Characters

Plant size and flower production were compared between female and hermaphroditic plants of two gynodioecious Chionographis. Frequency distribution of size and minimum size class of flowering plants were not different between two sex morphs in both Chionographis. In C. japonica ssp. hisauchiana, females produced more ovuliferous flowers than hermaphrodites, although the total number of flowers were not significantly different between two sex morphs. In contrast, hermaphrodites of C. japonica var. kurohimensis exceeded females in the total number of flowers, whereas the number of ovuliferous flowers was not significantly different between two sex morphs. Reproductive effort at flowering season is not different between females and hermaphrodites. These little differences in secondary sex characters, compared with dioecious species, are probably due to the selfing of hermaphrodites and weaknesses in gender specialization. Keywords: Chionographis, flower production, gynodioecy, plant size, secondary sex characters.

Use of a Heat Pump to Supply Energy to the Iodine-Sulphur Thermochemical Cycle for Hydrogen Production

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Yohann Dumont ◽  
Patrick Aujollet ◽  
Jean-Henry Ferrasse
Keyword(s):  
Hydrogen Production ◽  
Energy Distribution ◽  
Heat Pump ◽  
Production Efficiency ◽  
Nuclear Reactor ◽  
Distribution Network ◽  
Thermochemical Cycle ◽  
Total Energy Consumption ◽  
Important Place ◽  
Energy Needs

The hydrogen world consumption should increase significantly to progressively replace hydrocarbons. Due to its high power density, nuclear reactor should take an important place in this production. This paper focuses on the hydrogen production by thermochemical cycle using the heat available at 900°C of a new generation nuclear reactor. The chosen thermochemical cycle for this study is the iodine-sulphur thermochemical cycle water splitting.The process flowsheet under consideration has high total energy consumption. It has also many local energy needs unevenly distributed over a wide temperature range. The raw distribution of this energy gives a hydrogen production efficiency of 14.0%. To improve this, the proposed coupling is built using an energy distribution network with a coolant to meet the safety requirements. In this simple case, the efficiency of hydrogen production comes to 21.9%. By integrating a heat pump into the energy distribution network, the efficiency of production increases to 42.0%. The exergetic efficiency, increases from 59.3% to 85.8%.

Phytoplankton Summer Standing Crop and Annual Productivity as Functions of Phosphorus Loading and Various Physical Factors

1977 ◽  
Vol 34 (12) ◽  
pp. 2255-2270 ◽  
Author(s):  
Ray T. Oglesby
Keyword(s):  
Standing Crop ◽  
Phosphorus Loading ◽  
Water Volume ◽  
Physical Factors ◽  
Mixing Processes ◽  
Overlying Water ◽  
Mean Values ◽  
Annual Productivity ◽  
Variable Function ◽  
Morphoedaphic Index

Relations of phytoplankton summer standing crop and annual productivity to morphometric properties and edaphic factors, especially phosphorus loading, have been examined for a large, diverse, globally distributed group of lakes. Standing crop was highly correlated with dissolved phosphorus loading when mixing of the water column was taken into account. A regression applicable to lakes of all depths is given as a log-log function with predictive confidence intervals for summer mean values. Boundary conditions for the exclusion of certain lakes have been roughly determined. For lakes of mean depth > 25 m areal loading accounted for 97% of the variance in summer phytoplankton standing crop. Phosphorus inputs to shallower systems were adjusted to give a simple approximation of the influence of mixing processes and the ratio of bottom area to overlying water volume. Annual primary productivity seems to be a more complex and variable function of phosphorus loading than is summer standing crop. The former correlated fairly well with the morphoedaphic index. Productivity and standing crop showed well-defined trends in relation to other variables, but point scatter was so great that more exact definition of these functions was not justified. Key words: phytoplankton, phosphorus, eutrophication, lakes, morphoedaphic index

Energy budget of laboratory earthquakes: a comparison between linear elastic fracture mechanics approach and experimental approach.

2020 ◽  
Author(s):  
Marie Violay ◽  
Federica Paglialunga ◽  
François X. Passelègue
Keyword(s):  
Fracture Energy ◽  
Energy Budget ◽  
Strain Field ◽  
Normal Load ◽  
Energy Partitioning ◽  
Stick Slip ◽  
Earthquake Energy ◽  
Radiated Energy ◽  
Seismological Data ◽  
Order Of Magnitude

<p>Earthquakes correspond to a sudden release of elastic energy stored during inter-seismic period by tectonic loading around fault. The earthquake energy budget consists of four non-independent terms: the energy release rate (by unit crack length), the fracture energy, the heat term and finally the radiated energy. These terms depend on the rupture and sliding velocities, the amount of slip and the stress drop. Because of the impossibility to access to stress and strain conditions at depth, the earthquake energy budget cannot be fully constrained from seismological data, limiting our understanding of its influence on rupture propagation.</p><p>To address this issue, we conducted stick-slip experiments with large samples in a biaxial configuration apparatus. By imposing constant normal load and increasing shear load, seismic events were produced on a 20 cm long fault, for which the energy budget was estimated using different methods.</p><p>Fracture energy was estimated by recording the strain field around the crack tip through high frequency (2 MHz) strain gage rosettes array and comparing it to the theoretical LEFM strain field predictions obtained for same conditions (i.e. rupture velocity, distance from the fault). Fracture energies were then inverted and found to range in between 1 and 10 J/m<sup>2</sup>. At the same time the energy partitioning was estimated through stress-slip evolution during rupture. The fracture energies obtained from this method are almost one order of magnitude larger than the ones inverted from LEFM and range in between 1 and 90 J/m<sup>2</sup>. Moreover, the energy partitioning shows the radiated energy ranging between 80 and 300 J/m<sup>2</sup> and finally the heat/thermal energy as the largest fraction of the energy partitioning with values ranging from 200 to 2500 J/m<sup>2</sup>. Our preliminary results highlight the importance of understanding the contribution of heat energy in frictional processes, since this term cannot be estimated from seismological data.</p>

How diet influences energy partitioning in the regular echinoid Psammechinus miliaris; constructing an energy budget

2004 ◽  
Vol 304 (2) ◽  
pp. 159-181 ◽  
Author(s):  
Maria del Mar Otero-Villanueva ◽  
Maeve S Kelly ◽  
Gavin Burnell
Keyword(s):  
Energy Budget ◽  
Energy Partitioning ◽  
Psammechinus Miliaris
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