Rates of Food Exploitation by Littoral Fishes in a Mesotrophic North-Temperate Lake

1985 ◽  
Vol 42 (3) ◽  
pp. 556-566 ◽  
Author(s):  
D. Boisclair ◽  
W. C. Leggett
Keyword(s):  
Littoral Zone ◽  
Geometric Mean ◽  
Dry Weight ◽  
Benthic Invertebrate ◽  
Trophic Levels ◽  
Total Biomass ◽  
Temperate Lakes ◽  
Total Food ◽  
North Temperate Lakes ◽  
Food Consumed

The relationship between the biomass of food consumed by the littoral zone fish community of Lake Memphremagog, Quebec, and the total biomass of littoral zone food present was estimated on a daily and annual basis. The dominant food consumed were benthic invertebrates followed by forage fishes and plankton. The daily geometric mean exploitation rate was 0.55% of the total dry weight food biomass in the littoral zone. The corresponding annual rate was 72%. Energy equivalents were 0.81% (daily) and 105% (annual). When benthic invertebrate biomass values were adjusted to more accurately reflect availability (on the basis of depth distribution in the sediments and size) the geometric mean dry weight exploitation rates were 0.80% (daily) and 104% (annual). Corresponding energy rates were 1.15% (daily) and 150% (annual). These rates are significantly lower than reported benthic P/B ratios for 21 north-temperate lakes. These data indicate that littoral zone fishes crop only a very small fraction of the food biomass in the littoral zone. We conclude that the behaviors of both predator and prey act to limit the available fraction of the total food biomass and predict that the ratio of available to total food biomass in the littoral zone of north-temperate lakes will approximate 1%. This is consistent with existing empirical models linking fish production/biomass with biomass at lower trophic levels.

scholarly journals PREFERENCE OF TEMORA STYLIFERA (CALANOID COPEPOD) FOR PLANKTONIC CILIATES AND EGG PRODUCTION

2018 ◽  
Vol 29 ◽  
pp. 19-30
Author(s):  
Ngurah N. Wiadnyana
Keyword(s):  
Egg Production ◽  
Calanoid Copepod ◽  
Standing Stock ◽  
Total Biomass ◽  
Phytoplankton Assemblage ◽  
Planktonic Ciliates ◽  
Total Food ◽  
Quality Of Food ◽  
Food Consumed

The investigation of feeding and egg production of the calanoid co pepod Temora stylifera was carried out between September and November 1988. The copepods were fed on natural ciliates and phytoplankton assemblage. Planktonic ciliates composed of 2.20 to 3.83 g C l -1 representing 15.2 to 58.7% of total biomass in standing stock. They were consumed by these copepods at rates ranging from 11.25 to 38.14 g C mg DW-1  d-1 or about 27.6 to 74.8% of total food consumed. The increase of ciliates/phytoplankton biomass ratio in the food consumed by the copepods in the all experiments indicates the preference for ciliates, in which as a good quality of food they can improve the rates of copepods egg production.

The Job Of Microfinance For The Advancement Of Self Help Groups In India

2019 ◽  
Vol 118 (8) ◽  
pp. 236-240
Author(s):  
Dr.R. Murugesan ◽  
M. Leelavathi ◽  
Dr. K. Ravindran
Keyword(s):  
High Growth ◽  
High Growth Rate ◽  
Entrepreneurial Skills ◽  
Self Help ◽  
The Poor ◽  
Total Food ◽  
Self Help Groups ◽  
Positive Step ◽  
Food Consumed

towards jumping from the category of developing economy to developed economy there is one big factor that stops and poses a hindrance in its path of advancement and that obstacle is termed as Poverty. The Indian economic policy focuses on a high growth rate along with a equal participation of the poor so that they avail the opportunities available in the market economy. And in order to ensure the participation of the poor it has become important for the country to create a platform where the poor can easily access the various financial products. Microfinance is one such strategy for inclusive growth. Microfinance can change the life of the poor though not completely but a reasonable change can be ensured. In different phases of life women play a crucial role despite the discrimination that is faced by them. But equality can be endowed to women by enhancing the entrepreneurial skills in them. This is possible through Self Help Groups (SHGs). In India women produce around 30% of the total food consumed but she gets only 10% of the property or wealth of the country. Development of women is inevitable for the development and growth of any economy. SHGs happen to be a positive step in this direction. Along with these mediums there should be a cheap and easy source of credit for them and Microfinance fulfills the requirement. This study aims to find the role of this strong medium of Microfinance in the advancement of SHGs in India

The Utilisation of metabolic Water in Insects

1944 ◽  
Vol 35 (2) ◽  
pp. 127-139 ◽  
Author(s):  
G. Fraenkel ◽  
M. Blewett
Keyword(s):  
Body Weight ◽  
Water Content ◽  
Larval Development ◽  
Dry Weight ◽  
Larval Period ◽  
Tribolium Confusum ◽  
Ephestia Kuehniella ◽  
Final Size ◽  
Metabolic Water ◽  
Food Consumed

(1) Three insects,Tribolium confusum, Ephestia kuehniellaandDermestes vulpinus, have been grown at several humidities and the following factors have been determined: length of larval period; water content of food and of the freshly formed pupae; wet and dry weight of pupae and wet and dry weight of food consumed during larval development. The “net utilisation” of the food has been calculated as the ratio of dry weight of food eaten per larva to dry weight of pupa.(2) At lower humidities more food is eaten to produce a given unit of body weight. The length of the larval period increases and the weight of the pupae decreases.(3) More food is eaten at low humidities, because part of the food is utilised as water. As a consequence of this, the larva grows more slowly and its final size is smaller. It is shown forDermestesat 30 per cent. andEphestiaat 1 per cent. R.H. that less than 32·9 and 7·6 per cent. of the water in the pupae can be derived from water ingested with the food.

scholarly journals Sulfur application alleviates chromium stress in maize and wheat

2020 ◽  
Vol 18 (1) ◽  
pp. 1093-1104
Author(s):  
Grzegorz Kulczycki ◽  
Elżbieta Sacała
Keyword(s):  
Adverse Effects ◽  
Mineral Nutrition ◽  
Elemental Sulfur ◽  
Marked Decrease ◽  
Total Yield ◽  
Growth Yield ◽  
Dry Weight ◽  
Total Biomass ◽  
Cr Content ◽  
Chromium Stress

AbstractThis study aimed to examine the influence of increasing doses of chromium (Cr) (26, 39, and 52 mg kg−1 soil) and elemental sulfur (S) (60 mg kg−1 soil) on growth, yield, and mineral nutrition in wheat and maize. Macro- and micronutrients and Cr concentrations were determined in the aboveground parts of plants. All examined doses of Cr caused a marked decrease in the fresh and dry weight of maize. Wheat was more tolerant than maize, and lower Cr doses caused a small but statistically significant increase in the total yield. Wheat accumulated more than twofold Cr than maize, and the concentrations increased with higher Cr concentrations in the soil. The application of S significantly improved the total biomass production and lowered the Cr content in both plants. Cr changed the mineral nutrition in both cereals, but the pattern of changes observed was not the same. Applying S alleviated some adverse effects caused by the Cr. Hence, it is concluded that the application of elemental S may be an effective strategy to reduce adverse effects in plants grown on soil contaminated by heavy metals, especially Cr.

Diet of European freshwater pearl mussels Margaritifera margaritifera (Mollusca: Bivalvia: Unionoida) in small river (Republic of Karelia, Russia)

2021 ◽  
Vol 325 (4) ◽  
pp. 502-515
Author(s):  
S.F. Komulaynen
Keyword(s):  
Algal Species ◽  
Dry Weight ◽  
Lake Ladoga ◽  
Total Biomass ◽  
Margaritifera Margaritifera ◽  
Pearl Mussel ◽  
Organic Detritus ◽  
Unicellular Algae ◽  
Wide Range ◽  
Intestinal Contents

The freshwater pearl mussel Margaritifera margaritifera (Linnaeus,1758) is endangered in Europe and is now listed in the Red Data Book of many countries and regions. The diet of the species in the Syskyänjoki River (a tributary of Lake Ladoga) has been studied. The contents of the intestine generally correspond to the composition of seston, and include organic detritus, filamentous and unicellular algae, fragments of invertebrates and macrophyte tissues mixed with silt and sand. The total biomass of the intestinal contents of varied from 0.8 to 30.6 mg per organism (absolutely dry weight). Margaritifera margaritifera consumes a wide range of particles, from 0.5 μm3 (bacteria and unicellular algae) to 200 000 μm3 (fragments of invertebrates and macrophyte tissues). About 90–95% (by volume) of the intestinal contents was consisted by fine organic detritus. The food composition did not differ significantly for mollusks of different sexes and size. In the intestinal contents, 63 taxa of algae were identified. The number of algal species in the content of one intestine varied from 3 to 17, with their abundance from 250 to 9560 cells per organism. The most abundant and constant in the contents of the intestines are unicellular algae. Diatoms are the most diverse, they make up 50.8% of the total number of species.

scholarly journals Uptake and trophic changes in polybrominated diphenyl ethers in the benthic marine food chain in southwestern British Columbia, Canada

FACETS ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 20-51
Author(s):  
Brenda Burd ◽  
Chris Lowe ◽  
Carmen Morales-„Caselles ◽  
Marie Noel ◽  
Peter Ross ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Polybrominated Diphenyl Ethers ◽  
Dry Weight ◽  
Trophic Levels ◽  
Marine Food Chain ◽  
Deposit Feeders ◽  
Diphenyl Ethers ◽  
Bottom Fish ◽  
Harbour Sediment ◽  
Marine Food

We examined the physical and geochemical effects of sediment on the uptake of polybrominated diphenyl ethers (PBDEs) into marine sediment feeders and their transfer to higher trophic fauna. Sediment PBDEs increased with % total organic carbon (%TOC), organic carbon (OC) flux and grain size (%fines). Tissue PBDE variance was best explained ( R2 = 0.70) by sediment acid volatile sulfides (AVS), PBDEs, and organic lability and input, with the highest values near wastewater outfalls. Dry weight tissue/sediment PBDEs declined with increasing sediment PBDEs, resulting in tissue dilution (ratio <1) at >10 000 pg/g in harbours. Ratios also decreased with increasing %fines, resulting in regional differences. These patterns imply that high levels of fines and high sediment concentrations make PBDEs less bioavailable. Dry weight PBDEs increased >100× between background deposit feeders and predators (polychaetes, crabs, bottom fish, seal), but lipid normalized PBDEs barely increased (<1.3%), suggesting remarkably high uptake in low-lipid sediment feeders, and that PBDEs don’t accumulate at higher trophic levels, but lipid content does. Filter feeders had lower lipid-normalized PBDEs than deposit feeders, highlighting the importance of food resources in higher trophic fauna for bioaccumulation. The most profound congener change occurred with sediment uptake, with nona/deca-BDEs declining and tetra-hexa-BDEs increasing. Harbour sediment feeders had more deca-BDEs than other samples, suggesting PBDEs mostly pass unmodifed through them. Deca-BDEs persist patchily in all tissues, reflecting variable dependence on sediment/pelagic food.

scholarly journals   Effect of elevated CO2 and temperature on phosphorus efficiency of wheat grown in an Inceptisol of subtropical India

2012 ◽  
Vol 58 (No. 5) ◽  
pp. 230-235 ◽  
Author(s):  
Manoj-Kumar ◽  
A. Swarup ◽  
A.K. Patra ◽  
J.U. Chandrakala ◽  
K.M. Manjaiah
Keyword(s):  
Grain Yield ◽  
Dry Weight ◽  
P Uptake ◽  
Utilization Efficiency ◽  
Phosphorus Efficiency ◽  
Total Biomass ◽  
P Efficiency ◽  
Plant Parts ◽  
P Fertilizer ◽  
P Utilization

In a phytotron experiment, wheat was grown under two levels of atmospheric CO<sub>2</sub> [ambient (385 ppm) vs. elevated (650 ppm)], two levels of temperature (ambient vs. ambient +3&deg;C) superimposed with three levels of phosphorus (P) fertilization: 0, 100, and 200% of recommended dose. Various measures of P acquisition and utilization efficiency were estimated at crop maturity. In general, dry matter yields of all plant parts increased under elevated CO<sub>2</sub> (EC) and decreased under elevated temperature (ET); however, under concurrently elevated CO<sub>2</sub> and temperature (ECT), root (+36%) and leaf (+14.7%) dry weight increased while stem (&ndash;12.3%) and grain yield (&ndash;17.3%) decreased, leading to a non-significant effect on total biomass yield. Similarly, total P uptake increased under EC and decreased under ET, with an overall increase of 17.4% under ECT, signifying higher P requirements by plants grown thereunder. Although recovery efficiency of applied P fertilizer increased by 27%, any possible benefit of this increase was negated by the reduced physiological P efficiency (PPE) and P utilization efficiency (PUtE) under ECT. Overall, there was ~17% decline in P use efficiency (PUE) (i.e. grain yield/applied P) of wheat under ECT. &nbsp;

scholarly journals Improved Lycopene Production from Different Substrates by Mated Fermentation of Blakeslea Trispora

Foods ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 120 ◽  
Author(s):  
Ayse Sevgili ◽  
Osman Erkmen
Keyword(s):  
Shake Flask ◽  
Orange Peel ◽  
Dry Weight ◽  
Blakeslea Trispora ◽  
Total Biomass ◽  
Lycopene Production ◽  
The Media ◽  
Orange Powder ◽  
Early Growth Phase ◽  
Indirect Relationship

The production of lycopene from different substrates by Blakeslea trispora in fermentation was investigated. Lycopene productions from 4 and 6% glucose (pH 6.5) in shake flask fermentation were 77.7 and 28.1 mg L−1. Increasing the glucose concentration to 6% resulted in a decrease in lycopene production by 36.2%. A maximum lycopene concentration of 944.8 mg L−1 was detected with 4% glucose supplemented with 1.0 % sunflower oil in fermentor studies. Lycopene productions in the presence of sunflower and corn oils in the fermentor were 12.2 and 11.1 times higher, respectively, then without oil from 4 % glucose in a shake flask. Lycopene production from orange peel was two times higher in the fermentor than in the shake flask. Zygospores of B. trispora are the morphological forms, which are responsible for the production of the lycopene. The highest level of zygospores was correlated with the highest amount of intracellular lycopene in the total biomass dry weight. The media containing only orange powder (1%) gave a 4.9 mg L−1 lycopene production in a fermentor. The biosynthesis of lycopene has been started in most cases simultaneously in the early growth phase even in trace amounts. Maximum lycopene concentration was obtained when the medium was supplied with sunflower and corn oils. There is an indirect relationship between biomass and lycopene concentration.

scholarly journals Evaluation of Chickpea (Cicer arietinum L.) Genotypes for Quality Seedlings

1970 ◽  
Vol 8 (2) ◽  
pp. 108-116
Author(s):  
Shahrina Akhtar ◽  
Jalal Uddin Ahmed ◽  
Abdul Hamid ◽  
Md Rafiqul Islam
Keyword(s):  
Biomass Production ◽  
Plant Biomass ◽  
Function Analysis ◽  
Dominant Role ◽  
Seedling Emergence ◽  
Genotypic Variation ◽  
Dry Weight ◽  
Total Biomass ◽  
Maximum Variance ◽  
Total Dry Weight

A study was conducted to evaluate 100 chickpea genotypes to explore their genetic diversity in respect of emergence and growth attributes. A high genotypic variation was observed in the characters studied. The highest positive correlation corresponded to the root mass and total plant biomass of the seedlings. Seedling biomass production was highly subjective to seedling vigor. Using discriminant function analysis, the first two functions contributed 46.2 and 39.0%, and altogether 85.2% of the variability among the genotypes. Function 1 was positively related to dry weight of root and total plants. The character with the greatest weight on function 2 was seedling emergence rate. The total dry weight of seedlings played the most dominant role in explaining the maximum variance in the genotypes. The genotypes were grouped into six clusters. Each cluster had specific seedling characteristics and the clusters 5 and 6 were closely related and clearly separated from clusters 1 and 4 for their higher amount of root and total biomass production, and vigorous seedlings, where as, the genotypes in cluster 2 and 3 were intermediate. The genotypes in cluster 5 followed by cluster 6 appeared to be important resources for selecting and developing chickpea variety. Keywords: Chickpea; genotypes; seedling; quality DOI: 10.3329/agric.v8i2.7584 The Agriculturists 8(2): 108-116 (2010)

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