scholarly journals Interspecific Variations in Duration of Tail Regression in Two Tropical Anurans

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Cuckoo Mahapatra ◽  
Pravati Kumari Mahapatra
Keyword(s):  
Environmental Conditions ◽  
Rainy Season ◽  
Larval Period ◽  
Evolutionary Strategies ◽  
Interspecific Difference ◽  
Extreme Temperatures ◽  
Larval Phase ◽  
Morphological Variations ◽  
Interspecific Variations ◽  
Tadpole Tail

Anurans breed in an array of habitats and hence employ a variety of evolutionary strategies to adapt to the variable conditions. Particularly, since they undergo a larval phase they develop mechanisms to overcome unfavourable conditions like desiccation, extreme temperatures, and so forth. The anurans, Polypedates maculatus and Duttaphrynus melanostictus, show noticeable variation in the duration of larval period and tadpole tail regression. D. melanostictus breeds throughout the year and hence is subjected to different environmental conditions as compared to P. maculatus which breeds only during the rainy season. Thus, the tadpoles of D. melanostictus have selected to undergo a shorter larval period and duration of tail regression to suit their breeding habits. The present study correlates the interspecific difference in the duration of tail regression with the morphological variations in the tails of the two species. D. melanostictus shortens the duration of larval tail regression by having comparatively larger and more number of melanocytes and a thinner notochord than P. maculatus.

scholarly journals Morphological Variations of Wild Populations of Brycon dentex (Characidae, Teleostei) in the Guayas Hydrographic Basin (Ecuador). The Impact of Fishing Policies and Environmental Conditions

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1901
Author(s):  
Ana Gonzalez-Martinez ◽  
Carmen De-Pablos-Heredero ◽  
Martin González ◽  
Jorge Rodriguez ◽  
Cecilio Barba ◽  
...  
Keyword(s):  
Discriminant Analysis ◽  
Environmental Conditions ◽  
Anthropogenic Activity ◽  
Freshwater Species ◽  
Fishing Pressure ◽  
Wild Populations ◽  
Morphometric Variation ◽  
Morphological Variations ◽  
Body Development ◽  
The Impact

The Guayas, located in Ecuador, is the largest basin in the Pacific Ocean and has an inventory of 123 native freshwater species. Most of these are endemic species that are threatened or at-risk due to anthropogenic activity and the modification, fragmentation, and destruction of habitats. The aim of this study was to determine the morphometric variation in three wild populations of Brycon dentex in the Guayas basin rivers and their connections to fishing management and environmental conditions. A total of 200 mature fish were captured, and 26 morphometric parameters were measured. The fishing policies (Hypothesis 1) and environmental conditions (Hypothesis 2) were considered fixed factors and were validated by t-tests. The morphological variation among the three populations (Hypothesis 3) was validated through a discriminant analysis. Fishing policies and resource management were found to generate morphological differences associated with body development. In addition, the environmental conditions were found to influence the size and structure of Brycon dentex populations. The analyzed populations were discriminated by the generated morphometric models, which differentiated Cluster 1 (Quevedo and Mocache rivers) with high fishing pressure from Cluster 2 (Pintado river) with medium–low fishing pressure. Morphometric differentiation by discriminant analysis is a direct and economic methodology that can be applied as an indicator of diversity maintenance.

Distribution, feeding behaviour, and condition of Cape horse mackerel early life stages, Trachurus capensis, under different environmental conditions in the northern Benguela upwelling ecosystem

2014 ◽  
Vol 72 (2) ◽  
pp. 543-557 ◽  
Author(s):  
S. J. Geist ◽  
A. Kunzmann ◽  
H. M. Verheye ◽  
A. Eggert ◽  
A. Schukat ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Feeding Ecology ◽  
Environmental Conditions ◽  
Early Life ◽  
Early Life History ◽  
Horse Mackerel ◽  
Larval Phase ◽  
Recruitment Success ◽  
Wide Range ◽  
Variable Recruitment

Abstract Early life history (ELH) traits are key to understand variable recruitment success and hence the stock size of marine fish. One of the currently most puzzling ecosystems in this regard is the northern part of the Benguela Current upwelling system off Namibia. Here, populations of the formerly dominant pelagic species, sardine and anchovy, failed to recover during the last three decades after a dramatic decline. In contrast, Cape horse mackerel, Trachurus capensis, maintained a constant population size. Warming of the system and shoaling of hypoxic zones together with feedback loops within an altered foodweb are discussed to be responsible for this regime shift. In this study, we address the role of larval traits for the successful performance of the T. capensis population under the present environmental conditions with the focus on feeding ecology. We investigated seasonal variations of the geographical distribution, growth rate, feeding ecology, and nutritional condition of their ELH stages and examined relationships with water temperature, dissolved oxygen concentration, and micro-zooplankton composition. T. capensis' ELH stages showed a wide spatial and seasonal distribution, a preference for higher water temperatures (18–21°C) and presence over a wide range of dissolved oxygen concentrations (0.13–6.35 ml O2 l−1). Feeding success was high and mainly different groups of Copepoda were targeted, which were strongly size selected. The high dietary importance of micro-copepods during large parts of the larval phase indicates successful exploitation of this food source, which has increased in abundance during the last decade. It also explains observed best nutritional conditions at temperatures between 18 and 21°C, since these small copepods are commonly associated with warmer temperatures. Altogether, these traits enhance the species' probability to encounter suitable environments for the survival of their ELH stages, which is likely to lead to their high recruitment success in the northern Benguela ecosystem.

scholarly journals Study of Morphometric Aspects of Eri Silkworm (Samia ricini D.) reared on the host plant

2020 ◽  
pp. 192-196
Keyword(s):  
Host Plant ◽  
Significant Role ◽  
Environmental Conditions ◽  
Ricinus Communis ◽  
Larval Period ◽  
Larval Duration ◽  
Larval Weight ◽  
Larval Length ◽  
Qualitative Characters

The environmental conditions play a significant role and influence the quantitative and qualitative characters of silkworm such as larval length, larval breadth, larval weight and larval duration. Larvae of Eri silkworm (Samia ricini D.) were reared on Castor leaves (Ricinus communis). The data that were recorded for larval length (cm) from first to fifth instar are 0.76 ± 0.003; 1.49 ± 0.023; 3.09 ± 0.020; 4.39 ± 0.04 and 6.57 ± 0.04 respectively, for larval breadth (cm) are 0.122 ± 0.007; 0.24 ± 0.0; 0.46 ± 0.0; 0.74 ± 0.0 and 1.14 ± 0.0 respectively and for larval weight (g) are 0.007 ± 0.01; 0.033 ± 0.02; 0.37 ± 0.01; 1.07 ± 0.02 and 3.74 ± 0.03 respectively and the larval period of the reared larvae lasted for about 20 days.

scholarly journals Morphological Variations of Robusta Coffee As a Response to Different Altitude in Lampung

2019 ◽  
Vol 35 (2) ◽  
pp. 103-118
Author(s):  
Erwin Prastowo ◽  
Rina Arimarsetiowati
Keyword(s):  
Environmental Conditions ◽  
Morphological Characteristics ◽  
Fruit Weight ◽  
Leaf Length ◽  
Qualitative Variable ◽  
Morphological Variations ◽  
Agronomic Practices ◽  
Robusta Coffee ◽  
Length Width ◽  
Key Issues

The coffee growth is considered to depend, partly, on the environmental condition at which they develop to accomplish both vegetative and generative stages. An exploratory survey in Lampung aimed at investigating the morphological characteristics of 13 Robusta coffee accessions growing on different altitudes.Local superior coffee clones were selected from eight farms, and subjected to identifications. Three key issues were concerned for both quantitatively, i.e. plant components of leaves, branches, and fruits, and qualitatively such as leaves and fruit characteristics, i.e. colour and shape. The analysis shows a similarity of about 60% of total qualitative variable identified among different accessions. The remaining characters are suggested to be more varying such as flush colour, leaf surface, ripe fruit colour, and stipule shape. Furthermore, a quantitative analysis showed a higher level of similarity for fruit characters, i.e. fruit length, -width, and -thickness, and to a slightly lower level for leaf characteristics, i.e. leaf length and -width, and number of productive branches. It was revealed that some variables, i.e. fruit weight; leaf and seed; and canopy characteristics, explaining the morphological variation of coffee throughout the accessions. Furthermore, cluster analysis may indicated a possible similarity of coffee morphologies either from area with different or the same environmental conditions. A high heterogeneity related to environmental conditions, genotypic variations, plant nutritional status, and agronomic practices, which unable to confirm in the present study, may limit the specific conclusions.

LOSS OF TLD SIGNAL DUE TO HIGH TEMPERATURE ENVIRONMENTAL CONDITIONS

2019 ◽  
Vol 187 (1) ◽  
pp. 17-20
Author(s):  
Andrew Villanueva ◽  
Braden Goddard
Keyword(s):  
Saudi Arabia ◽  
High Temperature ◽  
Elevated Temperature ◽  
United Arab Emirates ◽  
High Temperatures ◽  
Environmental Conditions ◽  
Statistical Difference ◽  
Light Output ◽  
Nuclear Industry ◽  
Extreme Temperatures

Abstract While it is known that temperatures above 100°C have an effect on the reported dose of a TLD, it is less widely known what the susceptibility is to temperatures below 100°C, temperatures humans could reasonably expect to be exposed to. With the expanding nuclear industry in climates with more extreme temperatures, (e.g. United Arab Emirates and Saudi Arabia) the effect on a TLD if left on a dashboard of a car need to be evaluated. This research experimentally determined the extent of this thermal susceptibility by testing a range of high temperatures, 40°C – 90°C. The experimental results found that there is a statistically significant reduction in TLD-100H (natLiF:Mg,Cu,P) light output for TLDs there were exposed to temperatures as low as 40°C for 8 hour durations and 50°C for 2 hour durations. There is statistical difference in TLD-100H light output for elevated temperature durations of 8 hours compared to 24 hours.

Environmental conditions of the Suape estuarine-port complex area (Pernambuco, Brazil): phytoplankton biomass and hydrological parameters

2018 ◽  
Vol 99 (2) ◽  
pp. 291-301
Author(s):  
Isis Amália Cordeiro ◽  
Fernando Antônio Do Nascimento Feitosa ◽  
Manuel De Jesus Flores Montes ◽  
Amanda Yumi Otsuka ◽  
Alex Costa Silva
Keyword(s):  
Dissolved Oxygen ◽  
Environmental Conditions ◽  
Rainy Season ◽  
High Tide ◽  
Dry Season ◽  
Water Transparency ◽  
Industrial Complex ◽  
Productive Capacity ◽  
Chl A ◽  
Anthropogenic Action

The Suape coastal zone has suffered since the 1980s the effects of anthropogenic action due to the construction of the industrial complex of Suape. This work aimed to evaluate the environmental conditions and possible eutrophication processes of the area. Six campaigns were carried out, three in the dry season (November 2015, January and April 2016) and three in the rainy season (July 2015, July and August 2016). Water samples were collected at the surface during low tide and high tide, in neap tides. Salinity ranged from 19.75 to 37.20, the dissolved oxygen rate ranged from 61.75 to 125.90% and chlorophyll-a from 0.02 to 3.48 mg m−3. Water transparency, temperature, nitrate and silicate presented significant seasonal variation, the concentrations of nutrients being higher in the rainy season and the others in the dry season. Water transparency, salinity, dissolved oxygen saturation and chl-a <20 µm showed significant differences for tide, being higher at high tide, and at low tide for chl-a of <20 µm. The low content of dissolved inorganic nutrient salts and chl-a were indicative of an area still free of eutrophication. Anthropogenic changes in the environment have led to greater marine interference and consequently to a reduction of the productive capacity of the system.

scholarly journals Vessel Redundancy: Modeling Safety In Numbers

IAWA Journal ◽  
2007 ◽  
Vol 28 (4) ◽  
pp. 373-388 ◽  
Author(s):  
Frank W. Ewers ◽  
John M. Ewers ◽  
Anna L. Jacobsen ◽  
Jorge López-Portillo
Keyword(s):  
Environmental Conditions ◽  
Threshold Model ◽  
Evolutionary Strategies ◽  
Model Predictions ◽  
Independent Variable ◽  
Safety In Numbers

We examined the concept that high vessel number provides xylem safety and also show that under certain circumstances high vessel number may increase rather than decrease the probab ility of mortality. The independent variable was the number of vessels per organ (redundancy). The dependent variable was the probab ility of organ death for which we set three thresho1ds for catastrophic runaway embolism (50, 75 and 90% embolisrn). Results were calculated based upon the probability that any particu1arvesse1would become embolized (P). When the modeled p was below the runaway embolism thresho1d, the safety benefits (decreased probability of organ death) increased dramatically in going from one to ten vessels and approached maximum levels of safety in organs with lOO or more vessels.Vessel redundancy conferred the greatest advantage when p approached, but was less than, the runaway embolism threshold of the organ. However, when p exceeded the runaway embolism threshold the redund ancy relationship was reversed and safety was greatest in organs with lower vessel numbers. Having greater vessel redundancy increased the likelihood of an "average" result, i.e., mortality if p is above the threshold, and survival when p is below the threshold. Model predictions are discussed in terms of redundancy segmentation, stern splitting and various other ecological and evolutionary strategies for plants exposed to different environmental conditions.

scholarly journals Struktur Komunitas dan Kelimpahan Fitoplankton dan Zooplankton pada Musim Penghujan di Zona Intertidal Pantai Selatan Yogyakarta

2021 ◽  
Vol 24 (2) ◽  
pp. 167-176
Author(s):  
Ratih Ida Adharini ◽  
Namastra Probosunu
Keyword(s):  
Community Structure ◽  
Environmental Conditions ◽  
Water Samples ◽  
Low Temperatures ◽  
Intertidal Zone ◽  
Rainy Season ◽  
Diversity Index ◽  
South Coast ◽  
Wet Season ◽  
Dominance Index

Plankton is an organism that plays an important role as a water food reserve, which is influenced by environmental conditions. This study aims to determine the community structure, abundance and biodiversity of phytoplankton and zooplankton in the intertidal zone of south coast of Yogyakarta during the rainy season. The research was conducted at Pantai Drini, Kukup, and Sundak of Gunungkidul District during December 2016 - February 2017. Sampling was conducted on three observation stations in the intertidal zone of Drini Beach, Kukup, and Sundak twice a month. The water samples were taken with plankton nets number 25, then were fluidized in 4% formalin and stored at low temperatures. The results showed diversity index of plankton in Kukup Beach in January at 1.86 while the lowest value in February at Sundak Beach was 0.87. The highest plankton abundance in January at Sundak Beach was 900 individu L-1 while the lowest value in December at Kukup Beach was 217.8 individu L-1. Based on the diversity index of Shannon-Wiener, intertidal coast waters of Yogyakarta in wet season is categorized as moderate, and dominance index is categorized  as low. Plankton merupakan organisme yang berperan penting sebagai cadangan makanan perairan dan dipengaruhi oleh kondisi lingkungan. Penelitian ini bertujuan untuk mengetahui struktur komunitas, kelimpahan dan keanekaragaman plankton pada zona inertidal pantai selatan Yogyakarta selama musim penghujan. Penelitian dilakukan di Pantai Drini, Kukup, dan Sundak Kabupaten Gunungkidul selama bulan Desember 2016 – Februari 2017. Pengambilan sampel dilakukan pada tiga stasium pengamatan di zona intertidal Pantai Drini, Kukup, dan Sundak setiap dua minggu. Sampel air diambil dengan jaring plankton nomor 25, kemudian sampel plankton difiksasi dalam formalin 4% dan disimpan pada suhu rendah. Hasil penelitian menunjukan indeks keanekaragaman jenis plankton tetinggi di Pantai Kukup pada bulan Januari sebesar 1,86 sedangkan nilai terendah pada bulan Februari di Pantai Sundak sebesar 0,87. Kelimpahan plankton tertinggi pada bulan Januari pada Pantai Sundak sebesar 900 individu L-1 sedangkan nilai terendah pada bulan Desember di Pantai Kukup yaitu 217,8 individu L-1. Berdasarkan indeks keanekaragaman Shannon-Wienner maka indeks keanekaragaman di pantai selatan Yogyakarta tergolong rendah-sedang dengan indeks dominansi tergolong rendah.

scholarly journals Aggregation of hepatic melanomacrophage centers in S. herzbergii (Pisces, Ariidae) as indicators of environmental change and well-being

2021 ◽  
Vol 73 (4) ◽  
pp. 868-876
Author(s):  
H.C. Viana ◽  
W.B. Jesus ◽  
S.K.L. Silva ◽  
M.B. Jorge ◽  
D.M.S. Santos ◽  
...  
Keyword(s):  
Young People ◽  
Environmental Conditions ◽  
Rainy Season ◽  
Well Being ◽  
Biomarker Of Exposure ◽  
Xenobiotic Biotransformation ◽  
Sciades Herzbergii ◽  
Histological Procedure ◽  
Hematoxylin Eosin ◽  
Different Levels

ABSTRACT The melanomacrophage centers (MMCs) in the liver of fish are indicators of environmental conditions, as they are involved in xenobiotic biotransformation. The objective of this study was to evaluate the number of MMC in the liver of juveniles and adults of Sciades herzbergii from areas with different levels of contamination. The fish were caught at three points (reference - A1, potentially impacted - A2 and contaminated - A3), in São José bay (Maranhão, Brazil), in four samples. The livers were subjected to the standard histological procedure and 5μm sections were stained with hematoxylin-eosin. In livers of A2 adult individuals (260.50±161.50 MMCs / mm²) they presented a greater number of MMCs when compared to A3 adults (60.00 ± 30.10 MMCs / mm²). Juveniles showed considerable values in A1 (100.00 ± 0.00 MMCs/mm²) and A2 (95.33 ± 33.00 MMCs / mm²) compared to juveniles in A3 (49.00±0.00 MMCs/mm²). These high values are unexpected for young people. The average number of MMC correlated with the rainy season in the region. The use of hepatic MMCs as a biomarker of exposure to pollutants, in particular substances from fisheries systems, such as ammonia and nitrite, proved to be adequate to differentiate areas with different levels of impacts.

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