scholarly journals Numbers and biomass of soil invertebrates in a reserved field in central Finland

1979 ◽  
Vol 51 (1) ◽  
pp. 172-187 ◽  
Author(s):  
Timo Törmälä
Keyword(s):  
Soil Surface ◽  
Dry Weight ◽  
Soil Invertebrates ◽  
Soil Invertebrate ◽  
Total Biomass ◽  
Invertebrate Community ◽  
Wet Weight ◽  
The Mean ◽  
Individual Size ◽  
Diptera Larvae

The numbers and biomasses of soil invertebrates were investigated in a reserved field in central Finland. Samples were taken monthly from June to September. Five methods were employed to extract the animals from the soil samples. The animals were counted, measured and their dry biomasses were estimated by body length/weight regressions and dry weight/wet weight ratios derived from the literature. In July the total biomass of the soil invertebrate community (excluding Protozoa, Tardigrada and Rotatoria) was about 9.6 g dry weight m-2. The most dominant groups were Lumricidae (73.1 %), Enchytraeidae (5,7 %), Oribatei (5.0 %), and Nematoda (4.4 %). In September the biomass of Diptera larvae was high (1.0 g dw m-2). In numbers nematodes were superior (maximum 12 million m-2) to other groups. Oribatei, Mesostigmata and Collembola were more concentrated to the soil surface than other Acari, Enchytraeidae and Nematoda. The mean individual size decreased with depth in all of the studied groups.

THE EFFECT OF INGESTED CHLORTETRACYCLINE ON SOME HYDROLASES AND ORGANS ASSOCIATED WITH THE DIGESTIVE PROCESS IN GROWING PIGS: II. PROTEASE, AMYLASE, AND GELLULASE ACTIVITY OF THE CONTENTS OF THE SMALL INTESTINE AND OF THE CECUM; WEIGHTS OF SMALL INTESTINE AND MUCOSA

1957 ◽  
Vol 35 (3) ◽  
pp. 195-202 ◽  
Author(s):  
M. A. A. Vonk ◽  
L. W. McElroy ◽  
R. T. Berg
Keyword(s):  
Small Intestine ◽  
Dry Matter ◽  
Cellulase Activity ◽  
Dry Weight ◽  
Growing Pigs ◽  
Weanling Pigs ◽  
Intestinal Contents ◽  
Wet Weight ◽  
The Mean ◽  
Ad Libitum

Four treatments, involving differences in method of feeding and interval between last feed and slaughter, were employed in a study of the effect of dietary chlortetracycline on protease, amylase, and cellulase activity in the intestinal and cecal contents of 16 pairs of weanling pigs. Most consistent results were obtained with six pairs which were limited pair-fed except for the final feeding during which feed was available ad libitum for a 4-hour period ending 18 hours before slaughter. The mean total activities of all three hydrolases in the contents of the small intestines and of the ceca of the antibiotic-fed animals of these six pairs were significantly greater than in those of the control animals. Expressed as activity per gram dry matter of intestinal contents, significantly higher values for protease and amylase, but not for cellulase, were observed in the pigs that had received chlortetracycline. When the combined results obtained from all 16 pairs of the experimental animals were analyzed, the results showed that on a basis of activity per gram dry matter of intestinal contents, ingested chlortetracycline was associated with significant increases in amylase and cellulase but not in protease activity. Protease, amylase, and cellulase activities per gram dry matter of cecal contents were higher for pigs fed the antibiotic than for their controls. The mean wet weight of the empty small intestine and the mean dry weight of the mucosa scraped from the anterior 3-meter section of the small intestine were lower for the chlortetracycline-fed animals, but the differences were not statistically significant.

scholarly journals The effect of iron supplements on pregnancy in rats given a low-zinc diet

1984 ◽  
Vol 52 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Susan J. Fairweather-Talt ◽  
Viv Payne ◽  
Christine M. Willians
Keyword(s):  
Fetal Growth ◽  
Normal Level ◽  
Dna Content ◽  
Wistar Rats ◽  
Dry Weight ◽  
Iron Supplements ◽  
Zn Concentration ◽  
Female Wistar Rats ◽  
Wet Weight ◽  
The Mean

1. Female Wistar rats were given an adequate-zinc (60 μg/g) or low-Zn (7 μg/g) diet for a minimum of 2 weeks and then mated. They were then either continued on the same diets (+Zn –Fe or –Zn –Fe) or given similar diets supplemented with four times the normal level of iron (+Zn + Fe or –Zn + Fe). The day before parturition they were killed and the fetuses removed and analysed.2. There were no differences in numbers of fetuses or the number of resorption sites. In the absence of Fe supplementation, the mean fetal wet weight was significantly less (P < 0.05) in the low-Zn group but there was no effect of Zn in the two Fe-supplemented groups. The addition of Fe significantly decreased (P < 0.05) the mean fetal wet weight in the adequate-Zn groups but had no effect in the low-Zn groups. There were no differences in fetal dry weight, fat, protein or DNA content. Both Fe-supplemented groups produced fetuses of higher Fe concentration (P < 0.01), and mothers with higher bone Fe-concentration (P < 0.01) compared with the non-supplemented groups. The low-Zn groups produced fetuses of lower Zn concentration (P < 0,001) than the adequate-Zn groups but there was no effect on maternal bone Zn concentration.3. It was concluded that Fe-supplements did not adversely affect fetal growth from mothers given a low-Zn diet, but the addition of Zn to the unsupplemented diet increased fetal wet weight. These findings were not accompanied by any other differences in fetal composition or dry weight, and do not therefore lend support to the suggestion of an Fe-Zn interaction.

scholarly journals Relating Plant Architecture to Eggplant Fruit Quality

2013 ◽  
Vol 138 (6) ◽  
pp. 428-432
Author(s):  
Brian A. Kahn
Keyword(s):  
Fruit Quality ◽  
Solanum Melongena ◽  
Soil Surface ◽  
Dry Weight ◽  
Fruit Production ◽  
Fruit Rot ◽  
Individual Plant ◽  
Shoot Dry Weight ◽  
The Mean ◽  
Marketable Fruit

A 2-year study was conducted at Bixby, OK, to examine shoot characteristics of several eggplant (Solanum melongena) cultivars, including the vertical distribution patterns of fruit production, and to examine possible relationships of these traits to aspects of fruit quality. Plants of 11 cultivars of purple-fruited eggplant were field-grown following local production practices. Fourteen harvests of fruit that had reached horticultural maturity were made from 99 plants in each year over a period of ≈45 days per year. On each harvest date, every fruit that was harvested from an individual plant was charted. Before a fruit was severed from the plant, heights were measured from the soil surface to the pedicel attachment and to the blossom end. Each fruit was then weighed and categorized for marketability. On the day after the final harvest, each data plant was measured for height and diameter of the main stem and then severed at soil level for subsequent measurement of shoot dry weight. ‘Classic’, ‘Dusky’, ‘Megal’, and ‘Santana’ were the only cultivars that produced more than 50% marketable fruit in both years. There were no consistent relationships between plant height, stem diameter, or shoot dry weight and fruit quality. For a given cultivar, the fruiting plane was defined as the vertical space in which fruit were found over the course of the harvest period. This was delimited at the top by the mean height above the soil of the point of pedicel attachment and at the bottom by the mean height above the soil of the blossom end. The cultivars differed in fruiting planes, but height of fruit set was relatively unimportant as a determinant of overall fruit quality. Cull fruit usually had blossom ends that were higher off the ground than marketable fruit. The primary reason for cull fruit production was determined for two cultivars: ‘Black Beauty’ had poor fruit color and ‘Black Bell’ was relatively susceptible to fruit rot (primarily caused by Phomopsis vexans). Fruit scarring was found to be a major contributor to cull fruit production. Cultivars differed in fruit scarring in 1 of 2 years, and there was evidence that scarred fruit occurred higher in the crop canopy than marketable fruit.

scholarly journals Drivers of tropical soil invertebrate community composition and richness across tropical secondary forests using DNA metasystematics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Katie M. McGee ◽  
Teresita M. Porter ◽  
Michael Wright ◽  
Mehrdad Hajibabaei
Keyword(s):  
Land Use ◽  
Community Composition ◽  
Tropical Forests ◽  
Secondary Forest ◽  
Soil Invertebrates ◽  
Primary Forest ◽  
Soil Invertebrate ◽  
Secondary Forests ◽  
Invertebrate Community ◽  
Invertebrate Communities

Abstract Tropical forests are fundamental ecosystems, essential for providing terrestrial primary productivity, global nutrient cycling, and biodiversity. Despite their importance, tropical forests are currently threatened by deforestation and associated activities. Moreover, tropical regions are now mostly represented by secondary forest regrowth, with half of the remaining tropical forests as secondary forest. Soil invertebrates are an important component to the functioning and biodiversity of these soil ecosystems. However, it remains unclear how these past land-use activities and subsequent secondary forest developments have altered the soil invertebrate communities and any potential ecological consequences associated with this. DNA metabarcoding offers an effective approach to rapidly monitor soil invertebrate communities under different land-use practices and within secondary forests. In this study, we used DNA metabarcoding to detect community-based patterns of soil invertebrate composition across a primary forest, a 23-year-old secondary forest, and a 33-year-old secondary forest and the associated soil environmental drivers of the soil invertebrate community structure in the Maquenque National Wildlife Refuge of Costa Rica (MNWR). We also used a species contribution analysis (SIMPER) to determine which soil invertebrate groups may be an indication of these soils reaching a pre-disturbed state such as a primary forest. We found that the soil invertebrate community composition at class, order, family, and ESV level were mostly significantly different across that habitats. We also found that the primary forest had a greater richness of soil invertebrates compared to the 23-year-old and 33-year-old secondary forest. Moreover, a redundancy analysis indicated that soil moisture influenced soil invertebrate community structure and explained up to 22% of the total variation observed in the community composition across the habitats; whereas soil invertebrate richness was structured by soil microbial biomass carbon (C) (Cmic) and explained up to 52% of the invertebrate richness across the primary and secondary forests. Lastly, the SIMPER analysis revealed that Naididae, Entomobryidae, and Elateridae could be important indicators of soil and forest recuperation in the MNWR. This study adds to the increasing evidence that soil invertebrates are intimately linked with the soil microbial biomass carbon (Cmic) and that even after 33 years of natural regrowth of a forest, these land use activities can still have persisting effects on the overall composition and richness of the soil invertebrate communities.

scholarly journals Area, depth and elevation of cryoconite holes in the Arctic do not influence Tardigrada densities

2016 ◽  
Vol 37 (2) ◽  
pp. 325-334 ◽  
Author(s):  
Krzysztof Zawierucha ◽  
Tobias R. Vonnahme ◽  
Miloslav Devetter ◽  
Małgorzata Kolicka ◽  
Marta Ostrowska ◽  
...  
Keyword(s):  
Dry Weight ◽  
The Arctic ◽  
Glacier Surface ◽  
Independent Variables ◽  
Rapid Melting ◽  
Sediment Mixing ◽  
The World ◽  
Wet Weight ◽  
The Mean ◽  
Water Bears

Abstract Water bears (Tardigrada) are known as one of the most extremophile animals in the world. They inhabit environments from the deepest parts of the oceans up to the highest mountains. One of the most extreme and still poorly studied habitats which tardigrades inhabit are cryoconite holes. We analysed the relation between area, depth, elevation and tardigrades densities in cryoconite holes on four glaciers on Spitsbergen. The mean (±SD) of cryoconite area was 1287.21±2400.8 cm2, while the depth was on average 10.8±11.2 cm, the elevation 172.6±109.66 m a.s.l., and tardigrade density 24.9±33.0 individuals per gram of wet material (n = 38). The densities of tardigrades on Hans Glacier reached values of up to 168 ind. cm3, 104 ind. g−1 wet weight, and 275 ind. g−1 dry weight. The densities of tardigrades of the three glaciers in Billefjorden were up to 82 ind. cm2, 326 ind. g−1 wet weight and 624 ind. g−1 dry weight. Surprisingly, although the model included area, depth and elevation as independent variables, it cannot explain Tardigrada density in cryoconite holes. We propose that due to the rapid melting of the glacier surface in the Arctic, the constant flushing of cryoconite sediments, and inter-hole water-sediment mixing, the functioning of these ecosystems is disrupted. We conclude that cryoconite holes are dynamic ecosystems for microinvertebrates in the Arctic.

scholarly journals Heavy Metals in Muscle Tissue of Pterois volitans from the Veracruz Reef System National Park, Mexico

2019 ◽  
Vol 16 (23) ◽  
pp. 4611 ◽  
Author(s):  
Montoya-Mendoza ◽  
Alarcón-Reyes ◽  
Castañeda-Chávez ◽  
Lango-Reynoso ◽  
Zamudio-Alemán
Keyword(s):  
National Park ◽  
Microwave Digestion ◽  
Dry Weight ◽  
Atomic Absorption Spectrophotometry ◽  
National Standard ◽  
Pterois Volitans ◽  
Reef System ◽  
Wet Weight ◽  
The Mean ◽  
Mean Concentration

Concentrations of cadmium (Cd), lead (Pb), vanadium (V), and zinc (Zn) were measured in the muscle of 30 specimens of Pterois volitans, captured on April 2018, in the Veracruz Reef System National Park (VRSNP), Veracruz, Mexico. Concentrations, in the samples, were quantified with atomic absorption spectrophotometry (AAS), after microwave digestion. Results of the mean concentration, in descending order were V = 7.3 ± 0.7; Pb = 0.66 ± 0.07; Zn = 0.43 ± 0.14; and Cd = 0.03 ± 0.01 mg kg−¹ dry weight. These values did not exceeded limits established in the Mexican National Standard (NOM-242-SSA1-2009), of Cd and Pb (0.5 mg kg–¹) wet weight. This means that consumption of lionfish from this site does not pose a potential risk for human health.

scholarly journals IMPACT OF THE INVASIVE CUSCUTA CAMPESTRIS ON VEGETATIVE COVER AND PLANT BIODIVERSITY IN HOMA- BAY COUNTY

2021 ◽  
Vol 6 (1) ◽  
pp. 39-45
Author(s):  
Orwah Akoth ◽  
Okeyo Owuor ◽  
D Nyamai
Keyword(s):  
Host Plants ◽  
Photosynthetic Capacity ◽  
Dry Weight ◽  
Plant Biodiversity ◽  
Vegetative Cover ◽  
Significant Difference ◽  
Cuscuta Campestris ◽  
Wet Weight ◽  
The Mean ◽  
The Impact

Purpose: This research paper focused on the impact of Cuscuta campestris on vegetative cover and plant biodiversity in Homa-Bay County. The specific objective was to investigate the impact on plant growth and development with indicator as photosynthetic capacity of preferred host plants and chlorophyll content and leaf weight as the parameters. Methodology: The study was conducted in hot-spot areas of invasion, Rachuonyo North, Homa Bay town and Suba North using Completely Randomized Experimental Block Design. The data was collected through field observation and laboratory analysis. The study used descriptive and correlation data analysis procedures to show the impact on photosynthetic capacity, ANOVA to determine statistical significant difference among the obtained results for each parameter of the infected and uninfected samples. Variance analysis were conducted using SPSS 20 (IBM Corp. Armonk, NY, USA) and differences between means tested by ANOVA. Values of P ≤ 0.05 were considered significantly different. Findings: The results showed that the invasion was more intense in Theveta peruvinia and Euphorbia tirucalli species. Mean leaf amounts of chlorophyll were observed to decline with chlorophyll a from 3.97 to 1.59 mg/g and chlorophyll b from 2.65 to 1.18 mg/g and total chlorophyll value from 6.62 to 2.76 mg/g on infection resulting to reduced photosynthetic efficiency and low organic material formation. Leaf wet and dry weight significantly decreased in both infected varieties. The mean wet weight of 17.61g in infected was significantly different, F (1, 4) = 235.74, p< .05, from the mean wet weight of 24.23g in the uninfected Yellow Oleander while the mean dry weight of 5.55g in infected was significantly different, F (1, 4) = 159.72, p< .05, from mean dry weight of 7.87g in uninfected Yellow Oleander. Similarly, significant difference, F (1, 4) = 714.64, p< .05, was observed in Calliandra calothyrsus variety. These demonstrated how C. campestris is detrimental causing ecological impacts with direct effects on plant biodiversity by reducing growth and development of infected host plant and even leading to death. Unique Contributions to Theory, Practice and Policy: The paper recommends intense sensitization of the community on the impacts of dodder from the findings for an enhanced understanding and need for management and control. The findings to be disseminated through workshops involving farmers, NGOs and community based organisations, academic conferences and publications to help create awareness on the impacts and mobilize the entire public on management and possible total eradication. Further research to investigate on nutrients of attraction in the preferred host plants with an aim of permanent solution for total eradication in order to restore the vegetative cover and plant biodiversity.

scholarly journals Influence of spunbond degradable floating row covers on microclimate modification and yield of field cucumber

2018 ◽  
Vol 16 (2) ◽  
pp. e0902
Author(s):  
Andrzej Kalisz ◽  
Piotr Siwek ◽  
Konrad Sulak
Keyword(s):  
Sugar Content ◽  
Soluble Sugar ◽  
Soil Surface ◽  
Dry Weight ◽  
Row Covers ◽  
Plastic Materials ◽  
Radiation Maximum ◽  
The Mean ◽  
Degradable Materials ◽  
Conventional Oil

In recent years, there has been an increase in interest in innovative plastic materials for use in horticulture. The aim of this study was to examine the effects of (bio)degradable floating covers (polylactide nonwoven ‒ PLA, and oxo-degradable polypropylene nonwoven with 0.1% iron stearate ‒ PP photo, both 20 g/m2) compared to the conventional PP nonwoven (control, 20 g/m2) on microclimate modification and yield of field-grown cucumber. The greatest PAR transmittance was recorded for the control nonwoven (83%), while the degradable materials transmitted 8% less radiation. Maximum soil surface temperatures were the highest under the PLA nonwoven, but minimum temperatures ‒ under the oxo-degradable fleece. The mean temperature under the oxo-degradable material was comparable to the control, while PLA increased the soil temperature by 1.8 °C, on average. The yield from cucumber plants covered with degradable materials was similar to that from the plants cultivated under the conventional oil-based nonwoven fleece. There were no significant changes in dry weight and soluble sugar content in cucumber fruits in 2013; however, the degradable nonwovens decreased these parameters in 2012. The lifespan of the oxo-degradable nonwoven was limited only to one growing season, thus the durability of the polymer must be increased. Polylactide nonwoven can be a sustainable ecological alternative to conventional non-degradable PP covers.

scholarly journals Contamination of Omnivorous Freshwater Fish Species and Sediments by Chlorinated Hydrocarbons in Poland

2014 ◽  
Vol 58 (3) ◽  
pp. 405-411 ◽  
Author(s):  
Alicja Niewiadowska ◽  
Tomasz Kiljanek ◽  
Stanisław Semeniuk ◽  
Jan Żmudzki
Keyword(s):  
Organochlorine Pesticides ◽  
Aquatic Ecosystems ◽  
Dry Weight ◽  
Rutilus Rutilus ◽  
Fish Meat ◽  
Pcb Congeners ◽  
Vistula River ◽  
Spatial Differences ◽  
Wet Weight ◽  
The Mean

Abstract The occurrence and concentrations of organochlorine pesticides and polychlorinated biphenyls (PCBs) were determined in 158 muscle samples of bream (Abramis brama) and roach (Rutilus rutilus), and 84 samples of sediments collected from 10 river and lake sampling sites in 2011 and 2012. The concentrations of DDTs (p,p’-DDT, o,p’-DDT, p,p’-DDE, and p,p’-DDD), HCH isomers (a-, ß-, and y-HCH), HCB, and PCBs (six indicator PCB congeners 28, 52, 101, 138, 153 and 180) were determined using the capillary gas chromatography. The mean concentrations of DDTs in bream and roach were in the range of 11.2-654 and 4.5-121 ug/kg wet weight respectively, and PCBs were in the range of 1.3-75.9 and 1.1-112 ug/kg wet weight, respectively. Mean concentrations of DDTs and PCBs in sediments were 0.5-270 ug/kg dry weight and ⋋0.1-2.2 ug/kg dry weight respectively. The study showed clear spatial differences in the levels of organochlorine pesticides and PCBs in fish and sediments from different aquatic ecosystems. The highest levels of contaminants were detected in fish and sediments from the Vistula River in vicinity of Cracow. The possible risk to the fish meat consumers and ecological risk were evaluated.

Some influences of population density on Hymenolepis diminuta in rats

Parasitology ◽  
1975 ◽  
Vol 71 (3) ◽  
pp. 517-523 ◽  
Author(s):  
Carl Aage Hesselberg ◽  
Jørn Andreassen
Keyword(s):  
Population Density ◽  
Egg Production ◽  
Dry Weight ◽  
Hymenolepis Diminuta ◽  
Wet Weight ◽  
The Mean ◽  
Lower Recovery

When measured 56 days postinfection the length, wet weight and dry-weight of Hymenolepis diminuta were all found to decrease with increasing number of cysticercoids given up to 20. The mean position of the worms in 10, 12 and 20 worm infections is significantly posterior to that of 1, 2 and 5 worm infections and the worms are attached over a wider area of the intestine.Egg production by the worms was followed up to day 56 postinfection; the number of eggs produced per worm and even per rat decreased with increasing population density. Thus the best way to get most eggs and to maintain the parasite in the laboratory is to have rats infected with only one tapeworm.Rats given 1–20 cysticercoids showed a mean recovery of 100–65%, while rats given 40–200 cysticercoids showed a mean recovery ranging from 13 to 2%. In addition to ‘normal’ worms, defined as worms > 10 mm, small, most probably destrobilated, worms were found. In the 50 and 100 cysticercoid infections, worm recoveries were, respectively, 8% ‘normal’, 16% small, and 2% ‘normal’, 5% small. From the significantly lower recovery from heavy infections it is concluded that a deleterious factor is operating during the 8 weeks after the infection.

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