Particle-Size-Conversion Efficiency and Contaminant Concentrations in Lake Ontario Biota

1983 ◽  
Vol 40 (3) ◽  
pp. 328-336 ◽  
Author(s):  
Uwe Borgmann ◽  
D. M. Whittle
Keyword(s):  
Particle Size ◽  
Body Size ◽  
Conversion Efficiency ◽  
Food Chain ◽  
Lake Ontario ◽  
Dry Weight ◽  
Growth Efficiency ◽  
Fish Production ◽  
The Relationship ◽  
Zooplankton Production

The particle-size-conversion efficiency (log food consumption/production divided by log predator prey size ratio) is shown to be directly related to the relationship between the concentration of persistent contaminants accumulated primarily through the food chain and body size for organisms in pelagic ecosystems. The difference between particle-size-conversion efficiency for biomass and that for the contaminant gives the slope of the relationship between log contaminant concentration and log body size. This provides a useful theoretical framework for analyzing contaminant concentrations in aquatic biota without the need for specifying trophic level but still incorporating the idea of food chain accumulation. Concentrations of PCB, DDT, and mercury were examined in aquatic organisms from Lake Ontario, ranging in size from zooplankton to large salmonids (a 108 -fold range in dry weight). The slope of the double log plot of concentration versus weight varied from 0.20 to 0.22 for PCB and DDT and was approximately equal to 0.13 for mercury. This indicates that mercury is accumulated less efficiently through the food chain than PCB or DDT. After correcting for incomplete uptake and retention of the contaminant, an estimate of particle-size-conversion efficiency for biomass of about 0.26 was obtained, which agrees reasonably well with previous estimates obtained from growth efficiency experiments and analysis of particle-size spectra. These calculations indicate that potential fish production in Lake Ontario is ~ 120-fold lower than zooplankton production (for fish averaging 108-fold larger in body size as compared to zooplankton).Key words: particle-size-conversion efficiency, PCB, DDT, mercury, zooplankton production, fish production

Particle-size-conversion Efficiency, Invertebrate Production, and Potential Fish Production in Lake Ontario

1994 ◽  
Vol 51 (3) ◽  
pp. 693-700 ◽  
Author(s):  
U. Borgmann ◽  
D. M. Whittle
Keyword(s):  
Particle Size ◽  
Body Size ◽  
Conversion Efficiency ◽  
Lake Trout ◽  
Lake Ontario ◽  
Contaminant Concentration ◽  
Fish Production ◽  
Rainbow Smelt ◽  
Pelagic Species ◽  
Size Relationship

The relationships between body size and p,p′-DDE and total PCB concentration in Zooplankton, mysids, amphipods, slimy sculpin (Cottus cognatus), rainbow smelt (Osmerus mordax), alewife (Alosa pseudo-harengus), and lake trout (Salvelinus namayeush) in Lake Ontario were determined for samples collected from 1989 to 1992. Amphipods, and to a lesser extent sculpins, had higher DDE and PCB concentrations than predicted from the contaminant concentration – body size relationship for the pelagic species. PCB, but not DDE, concentrations in Zooplankton were also abnormally high. For the pelagic species, excluding PCB concentrations in Zooplankton, the log contaminant concentration – log body size relationship had a slope of 0.23 (95% confidence limits = ±0.014). Combined with revised estimates of the efficiency of contaminant retention from one body size to another (ε′ = 0.05–0.10), the revised estimate of particle-size-conversion efficiency (ε) for Lake Ontario falls between 0.27 and 0.35. Recent estimates of invertebrate (Zooplankton, mysid, and amphipod) annual production average 18 g/m2 (dry weight) with upper and lower limit estimates of 14–27 g/m2. Using ε to extrapolate from invertebrate to fish production results in estimates of mean potential fish production in Lake Ontario of 1–7 kg/ha (wet weight), as compared with previously published estimates of 6 and 14 kg/ha.

Particle-Size-Conversion Efficiency and Total Animal Production in Pelagic Ecosystems

1982 ◽  
Vol 39 (5) ◽  
pp. 668-674 ◽  
Author(s):  
Uwe Borgmann
Keyword(s):  
Particle Size ◽  
Conversion Efficiency ◽  
Animal Production ◽  
Size Spectrum ◽  
Fish Production ◽  
Pelagic Ecosystem ◽  
Simple Equations ◽  
Zooplankton Production ◽  
Pelagic Ecosystems

A method is described for defining conversion efficiency in pelagic ecosystems on the basis of particle size, rather than trophic level, this permits calculation of a size-corrected biomass function which can be used to describe total animal production by taking into account biomass losses resulting from carnivorous feeding in multitrophic level systems. This, in turn, permits the determination of potential fish production, for any given size fish, from experimental data on zooplankton production using simple equations. Little knowledge of trophic interactions is required. The potential fish production resulting from microzooplankton production in the Burlington Canal is calculated. Keywords: conversion efficiency, production, pelagic ecosystem, particle-size spectrum

scholarly journals INTRASPECIFIC VARIATION IN THE REPRODUCTIVE EFFORT AMONG THREE POPULATIONS OF AN INTERTIDAL GASTROPOD, Nerita japonica (Dunker)

2012 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Carolus Paruntu
Keyword(s):  
Body Size ◽  
Intraspecific Variation ◽  
Rocky Shore ◽  
Reproductive Effort ◽  
Dry Weight ◽  
Mature Gonad ◽  
Adult Body ◽  
Intertidal Gastropod ◽  
Intertidal Habitats ◽  
The Relationship

The aim of the present research is to figure out the reproductive effort of Nerita japonica occurring in three different intertidal habitats of Amakusa Shimoshima Island, western Kyushu, Japan. Rocky shore population and other two stony shore populations (the upper stony shore and the lower stony shore) were described based on: (a) its mean mature gonad dry weight, (b) reproductive effort, and (c) the relationship between reproductive effort and body size. Data recorded in the period of spawning season. The results revealed that there were mean mature gonad dry weight and reproductive effort variations among three snail populations. Mean mature gonad dry weight and reproductive effort were larger for the Rocky shore population, intermediate for lower stone shore population, and smaller for the upper stone shore population. In one out of three populations, i.e., the upper stone shore population, reproductive effort of mature females increased significantly with an increase in body size. The data showed that reproductive effort is related to adult body size of N. japonica. There was an intraspecific variation in reproductive effort among three populations of N. japonica over even small geographic distances. Keywords: mature body size, mature gonad dry weight, reproductive effort, intraspecific variation, Nerita japonica.  Variasi Indeks Kematangan Gonad Interspesies pada Tiga Populasi Gastropoda Intertidal, Nerita japonica (Dunder)) Penelitian ini bertujuan untuk mendeskripsikan indeks kematangan gonad dari gastropoda intertidal, Nerita japonica yang hidup di tiga habitat yang berbeda di Pulau Shimoshima Amakusa, Kyushu bagian barat, Jepang. Parameter yang diamati pada setiap populasi adalah: (a) nilai rata-rata berat kering gonad matang, (b) indeks kematangan gonad, dan (c) hubungan antara indeks kematangan gonad dan ukuran tubuh. Data dicatat pada periode musim pemijahan. Ketiga populasi memperlihatkan nilai rata-rata berat kering gonad yang matang dan indeks kematangan gonad yang berbeda. Populasi pantai berbatu memiliki nilai rata-rata berat kering matang gonad dan indeks kematangan gonad yang paling besar, diikuti oleh nilai dari populasi pantai berbatu bagian bawah dan populasi pantai berbatu bagian atas memiliki nilai yang paling kecil. Selanjutnya, satu dari tiga populasi, yaitu populasi pantai berbatu bagian atas memperlihatkan indeks kematangan gonad dari individu-individu betina N. japonica berhubungan dengan ukuran tubuhnya. Sekalipun indeks kematangan gonad dari individu-individu N. japonica meningkat secara signifikan dengan bertambahnya ukuran tubuh, namun terdapat variasi intraspesifik pada N. japonica dalam hal indeks kematangan gonad menurut habitat walaupun secara geografis berdekatan.Kata kunci: ukuran tubuh matang kelamin, berat kering gonad matang, indeks kematangan gonad, variasi intraspesifik, Nerita japonica.

The Relationship Between Colliery-waste Particle Sizes and Plant Growth

1974 ◽  
Vol 1 (4) ◽  
pp. 281-284 ◽  
Author(s):  
Christopher G. Down
Keyword(s):  
Particle Size ◽  
Plant Growth ◽  
Water Retention ◽  
Size Range ◽  
Growth Period ◽  
Dry Weight ◽  
Particle Sizes ◽  
Small Particles ◽  
The Relationship ◽  
Water Holding

Seed germination and dry-weight production in Lolium perenne were examined in relation to growth on 12-years-old colliery waste separated into seven size-fractions. The size-range was from more than 4,000 μ to less than 125 μ, and the growth period was up to 30 days. Germination percentages after 6 days generally increased with decreasing particle-size, as did dry-weight. Shoot : root ratios also showed an inverse relationship with particle size.After 30 days there was no distinction between dryweights on different particle sizes, except that on the largest fractions it had been found impossible to keep the plants alive. Problems of water-holding capacity are discussed, and the significance of soil particle-size in revegetation work is examined, it being concluded that an admixture of small particles is important for water retention and plant growth.

The Respiratory Physiology of the Marine Nematodes Enoplus Brevis (Bastian) and E. Communis (Bastian)

1973 ◽  
Vol 59 (1) ◽  
pp. 255-266
Author(s):  
H. J. ATKINSON
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Oxygen Tension ◽  
Dry Weight ◽  
Respiratory Physiology ◽  
Rate Of Oxygen Consumption ◽  
Oxygen Tensions ◽  
The Difference ◽  
Relationship Of ◽  
The Relationship

1. The rate of oxygen consumption of individual males of Enoplus brevis and E. communis was measured at 15 °C and at each of four oxygen tensions, 135, 75, 35, and 12 Torr, after at least 12 h experience of these conditions. 2. It was clearly demonstrated that the level of oxygen consumption of both species was reduced by each lowering of the imposed oxygen tension. 3. In all cases the oxygen consumption of each species fell with increasing body size. On a unit dry-weight basis the oxygen consumption of E. brevis is greater than that of the larger E. communis, but after allowing for the difference of body size the two species have more or less similar oxygen uptakes at all oxygen tensions. 4. In E. brevis oxygen tension influenced the relationship of body size and metabolism, the slope relating oxygen consumption and body weight becomes steeper with decreasing oxygen tension. This effect was not shown by E. communis. 5. Some general factors influencing the availability of oxygen to nematodes are considered.

Growth and respiration throughout the life-cycle of Nematospiroides dubius Baylis (1926) (Nematoda: Heligmosomidae): the parasitic stages

Parasitology ◽  
1974 ◽  
Vol 69 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Victoria Bryant
Keyword(s):  
Growth Rate ◽  
Life Cycle ◽  
Body Size ◽  
Dry Weight ◽  
Functional Importance ◽  
Male And Female ◽  
Nematospiroides Dubius ◽  
Whole Life Cycle ◽  
The Relationship

The growth of male and female parasitic stages of Nematospiroides dubius from male and female ASH/CS1 mice was measured in terms of dry weight. No sex-linked resistance of mice to infection with N. dubius was apparent, as growth was the same in both sexes of host. The growth rate did not alter when moulting occurred.All parasitic stages of N. dubius consumed oxygen in vitro and oxygen was also shown to be necessary for motility and survival.The relationship between body size and metabolic rate was established for male and female parasitic N. dubius and the b values indicated that aerobic metabolism is of functional importance to this species.The size/metabolism relationship for the whole life-cycle was established.

Relationship between Chronic Toxicity and Bioaccumulation of Cadmium in Hyalella azteca

1991 ◽  
Vol 48 (6) ◽  
pp. 1055-1060 ◽  
Author(s):  
U. Borgmann ◽  
W. P. Norwood ◽  
I. M. Babirad
Keyword(s):  
Humic Acid ◽  
Chronic Toxicity ◽  
Lake Ontario ◽  
Dry Weight ◽  
Complexing Agents ◽  
Distilled Water ◽  
Cd Accumulation ◽  
Twofold Increase ◽  
Fold Reduction ◽  
The Relationship

The chronic toxicity of Cd to Hyalella in Burlington City tap (Lake Ontario) water with additions of complexing agents, distilled water, or sediments was much more constant if toxicity was expressed as a function of Cd bioaccumulated, rather than the Cd concentrations added or measured in the water. Additions of 20 mg humic acid/L or 0.5 μM EDTA increased the 6-wk EC50 from 0.53 to 4.6 and 19 μg/L, respectively. The EC50 based on bioaccumulated Cd, however, increased from 38 to only 44 μg/g (dry weight). Addition of sediments increased the 4-wk EC50 by > 1000-, 13-, or 2.3-fold for EC50s based on nominal Cd added, Cd concentrations measured in water, or Cd concentrations accumulated by Hyalella, respectively. A 10-fold reduction in hardness caused a twofold increase in the 6-wk EC50 based on Cd accumulation. The relationship between survival and Cd bioaccumulation by Hyalella was, therefore, affected less by complexing agents, hardness, and sediments than was survival compared with concentrations in water. Published Cd concentrations in Hyalella from a number of Ontario lakes are close to levels associated with toxicity in the laboratory.

Age-related variation in the nutrient reserves of breeding American Coots (Fulica americana)

1987 ◽  
Vol 65 (10) ◽  
pp. 2417-2420 ◽  
Author(s):  
Ray T. Alisauskas ◽  
C. Davison Ankney
Keyword(s):  
Body Size ◽  
Age Groups ◽  
Principal Component ◽  
Dry Weight ◽  
Fulica Americana ◽  
Fat Reserves ◽  
Age Related ◽  
Nutrient Reserve ◽  
The Relationship ◽  
Nutrient Reserves

We analyzed the relationship between age and nutrient reserves of 186 American Coots, Fulica americana, collected in southern Manitoba during the breeding season in 1981. The first principal component from the correlation matrix of 13 morphological variables was used as the measure of body size. Protein reserves, as indexed by lean dry weight, and fat reserves were related to body size, but the relationship for fat reserves was weak. The oldest coots of each sex were the largest, and this partly explained their larger protein reserves compared with the youngest coots. However, by scaling different sex–age groups to the same body size, we found that older coots had relatively larger protein reserves before breeding than did younger coots. Males and females did not differ in relative protein reserves, but females had relatively more fat reserves than did males. The results also indicated that body size is an important consideration in studies of nutrient reserve dynamics.

Zebra Mussels as Biomonitors for Organic Contaminants in the Lower Great Lakes

1996 ◽  
Vol 31 (2) ◽  
pp. 411-432 ◽  
Author(s):  
Michael E. Comba ◽  
Janice L. Metcalfe-Smith ◽  
Klaus L.E. Kaiser
Keyword(s):  
Great Lakes ◽  
Organic Contaminants ◽  
Lake Erie ◽  
Soft Tissues ◽  
Lake Ontario ◽  
Dry Weight ◽  
Zebra Mussels ◽  
Organic Contamination ◽  
Contamination Levels ◽  
St Lawrence River

Abstract Zebra mussels were collected from 24 sites in Lake Erie, Lake Ontario and the St. Lawrence River between 1990 and 1992. Composite samples of whole mussels (15 sites) or soft tissues (9 sites) were analyzed for residues of organochlo-rine pesticides and PCBs to evaluate zebra mussels as biomonitors for organic contaminants. Mussels from most sites contained measurable quantities of most of the analytes. Mean concentrations were (in ng/g, whole mussel dry weight basis) 154 ΣPCB, 8.4 ΣDDT, 3.5 Σchlordane, 3.4 Σaldrin, 1.4 ΣBHC, 1.0 Σendosulfan, 0.80 mirex and 0.40 Σchlorobenzene. Concentrations varied greatly between sites, i.e., from 22 to 497 ng/g for ΣPCB and from 0.08 to 11.6 ng/g for ΣBHC, an indication that mussels are sensitive to different levels of contamination. Levels of ΣPCB and Σendosulfan were highest in mussels from the St. Lawrence River, whereas mirex was highest in those from Lake Ontario. Overall, mussels from Lake Erie were the least contaminated. These observations agree well with the spatial contaminant trends shown by other biomoni-toring programs. PCB congener class profiles in zebra mussels are also typical for nearby industrial sources, e.g., mussels below an aluminum casting plant contained 55% di-, tri- and tetrachlorobiphenyls versus 31% in those upstream. We propose the use of zebra mussels as biomonitors of organic contamination in the Great Lakes.

The Effect of Donor Molecular Structure on Power Conversion Efficiency of Small-Molecule-Based Organic Solar Cells

2019 ◽  
Vol 16 (3) ◽  
pp. 236-243 ◽  
Author(s):  
Hui Zhang ◽  
Yibing Ma ◽  
Youyi Sun ◽  
Jialei Liu ◽  
Yaqing Liu ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Small Molecule ◽  
Organic Solar Cells ◽  
Molecular Design ◽  
Power Conversion ◽  
The Relationship

In this review, small-molecule donors for application in organic solar cells reported in the last three years are highlighted. Especially, the effect of donor molecular structure on power conversion efficiency of organic solar cells is reported in detail. Furthermore, the mechanism is proposed and discussed for explaining the relationship between structure and power conversion efficiency. These results and discussions draw some rules for rational donor molecular design, which is very important for further improving the power conversion efficiency of organic solar cells based on the small-molecule donor.

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