Effet de certains paramètres physico-chimiques sur les relations prédateurs–proies dans les populations de copépodes cyclopoïdes des mares temporaires d'eau douce

1986 ◽  
Vol 64 (1) ◽  
pp. 8-11
Author(s):  
Louise Vallières ◽  
Antoine Aubin

Copepod populations of three temporary freshwater pools (Alnus unit, Carex unit, and Molinia unit) were studied using a standard approach (species versus abiotic factors) and a holistic one (body size and feeding ecology). Multiple regression analyses of data indicate that the physical and chemical features of water (temperature, pH, dissolved oxygen, mineral content, and depth) explain 62 to 98% of the variability of carnivorous copepods, while the abundance of their prey accounts for much less. No size class of prey seems to be preferred. The abundance of decaying organic matter, typical of such pools, would result in an overabundance of prey. Predators would then be under the control of nonalimentary factors.

Author(s):  
Stefanija MISEVIČIENĖ

The quality of water in rivers of central Lithuania is often bad due to intensive anthropogenic activities. When rivers flow through the town’s territory, concentrated pollution, such as rainwater, industrial and productional waste water discharges, contributes to diffuse sources of pollution. If biogenic substances are the main indicators for diffuse pollution, organic matter, expressed as BOD, is the indicator for concentrated pollution. The article provides the 2013 – 2017 monitoring data on the changes of organic matter in the water of the Dotnuvele and Smilga Rivers and discusses the reasons for fluctuations in concentrations of BOD7. The aim of the research is to investigate the changes in the organic matter of the Dotnuvele and Smilga Rivers, depending on meteorological factors. For chemical analysis, water samples were taken quarterly. Water analysis was carried out by the ASU Chemical Analytical Laboratory of Water Resources Engineering Institute. The amount of organic matter (BOD7) is calculated as the difference in oxygen content after 7 days of incubation, while the amount of dissolved oxygen (O2) in the water is determined by the electrochemical probe method. The concentrations of BOD7 and O2 in the water of both rivers is compared with the criteria for assessing the ecological status of surface water bodies. The research has shown that the dissolved oxygen concentrations in rivers’ water are strongly influenced by water temperature and precipitation. The lower the temperature, the more of the dissolved oxygen is found in rivers’ water (r = -0.64). A lower precipitation amount, which reaches the rivers, increases the amount of dissolved oxygen in them (r = -0.45). The increase of BOD7 concentrations in rivers’ water was caused by higher precipitation amount (r = 0.46), higher air (r = 0.41) and lower water temperature (r = -0.41). The ecological status of the Dotnuvele River was usually good, while Smilga was average.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Soufiane Fadlaoui ◽  
Ouahid El Asri ◽  
Mustapha Bouterfas ◽  
Mohammed Melhaoui

The large number of pollutants discharged into the aquatic environment may influence the physicochemical and biological qualities of the aquatic ecosystem. This study discloses the global quality of the surface waters and the effect of physicochemical variables on the abundance of the African freshwater crab Potamon algeriense inhabiting Zegzel watercourse, a mountain stream in the northeast of Morocco. Physicochemical variables including streamflow, water temperature, pH, dissolved oxygen, suspended matter, chloride, calcium, magnesium, ammonia, nitrite, nitrate, orthophosphate, and organic matter were evaluated monthly for one year (October 2017–September 2018). The evaluation of the physicochemical quality showed that the waters of all the stations studied are between the excellent and good quality classes concerning all the physicochemical variables and highlights also two variations with a tendency towards degradation, one spatial from upstream to downstream and the other seasonal from the wet to the dry period. The abundance of crabs was recorded to exhibit a positive correlation with dissolved oxygen, calcium (N = 44) (p < 0.01), and magnesium. However, a negative correlation has been noticed for streamflow (N = 1) (p < 0.01), water temperature, pH, suspended matter, chloride, ammonia, nitrite, nitrate, orthophosphate, and organic matter. The results obtained reveal that besides the biotic variables, the distribution of P. algeriense also depends on these specific environmental variables.


2019 ◽  
Vol 16 (3(Suppl.)) ◽  
pp. 0677
Author(s):  
AL-Ameen Et al.

In this study, a total of 209 individuals of leeches were collected from Al-Hindyia River / Babil Province. 116 individuals were identified as Erpobdella octaculata (Linnaeus, 1758), 50 individuals as Erpobdella punctata (Leidy,1870) and  43 individuals as Hemiclepsis marginata (Müller, 1774).  Four samples were collected monthly during a period from February to June 2018. Some physical and chemical water properties were also examined, including air and water temperature, potential of hydrogen pH, Electrical Conductivity EC, Total Dissolved Solid TDS, Dissolved Oxygen DO, and the Biological Oxygen Demand BOD₅.  Air and water temperature were ranged 19.5-29, & 14.6-23.2 °C respectively. The values of pH ranged 6.2-7.6. EC ranged 1104-1581 μs/cm². The TDS recorded 669- 767 mg/l, while the DO reached 1.3- 8.5 mg / l, the BOD₅ ranged 3.5- 5.7 mg/l.


Author(s):  
Titik Wijayanti

The study aims to determine the response of microalgae community structure codominant and abiotic factors change Sutami Malang waters due to the addition of the detergent concentration variation in ex-situ. The experiment was conducted in September 2007 to March 2008. The addition of the detergent concentration consists of four levels, namely D0 (0 ppm), D1 (0.1 ppm), D2 (2 ppm) and D3 (4 ppm) of detergent to the water reservoir. Variable dynamics of microalgae abundance and abiotic factors waters observed simultaneously and periodically every five days for 40 days. The results showed that increasing the concentration of detergent changing dynamics of microalgae community structure codominant. Detergents suppress the growth Ceratium at a concentration ≥ 0.1 ppm. Instead detergent Synedra population increases until day 30 and stimulate the growth of Microcystis. During the 40 days of observation, abiotic factors change due to the addition of detergent concentration, especially the increase in conductivity, Total Organic Matter, phosphate, nitrate and surfactant. In contrast to lower CO2-free detergents and Dissolved Oxygen. Changes in abiotic factors significantly affect the growth of microalgae codominant.


2018 ◽  
Vol 7 (1) ◽  
pp. 78-85
Author(s):  
Halimatus Sa’diyah ◽  
Norma Afiati ◽  
Pujiono Wahyu Purnomo

Kawasan mangrove dapat memproduksi bahan organik dari proses dekomposisi serasah yang jatuh yang menjadi penyuplai nuterien ke lingkungannya. Proses tersebut menggunakan oksigen terlarut yang apabila oksigen terlarut habis maka proses tersebut beralih ke proses dekomposisi secara anaerob yang menyebabkan terbentuknya senyawa H2S. Penelitian ini bertujuan untuk mengetahui perbedaan kandungan bahan organik sedimen dan kadar H2S air di dalam dan di luar kawasan mangrove serta untuk mengetahui hubungan kandungan kadar H2S air dengan bahan organik sedimen dan oksigen terlarut di kawasan mangrove desa Bedono. Metode penelitian adalah metode survey. Penelitian ini dilakasanakn pada bulan Mei- Juni 2017 di lokasi yang mewakili kawasan mangrove dan lingkungan sekitarnya. Data yang diukur adalah suhu air, kecerahan, kedalaman, kecepatan arus, oksigen terlarut, pH, bahan organik sedimen dan H2S air yang dilaksanakan empat kali dengan selang pengukuran dua minggu. Hasil yang didapat yaitu suhu air 28-31oC, kecerahan 14,5-68 cm, kedalaman 33-165 cm, kecepatan arus 0-0,1 m/s, oksigen terlarut , pH 5-6, bahan organik sedimen 7,73-20,27%, H2S air 0,003-0,037 mg/l. Kandungan bahan organik sedimen dan kadar H2S air tertinggi di dalam kawasan mangrove dengan rata-rata 16,36% dan 0,031 mg/l, dan terendah di luar kawasan mangrove dengan rata-rata 9,78% dan 0,01 mg/l. Kadar H2S tinggi di dalam kawasan mangrove dan lebih rendah di luar kawasan mangrove. Kadar H2S air dengan bahan organik sedimen dan oksigen terlarut berhubungan linier dengan persamaan H2S= 0,027 + 0,001BOS- 0,006 DO (r= 0,7246, BOS= Bahan Organik Sedimen, DO= Dissolved Oxygen). Mangroves produce organic matter from the decomposition of falling leaves, twigs etc, which supply nutrient to the environment. The process uses dissolved oxygen; when dissolved oxygen exhausted, it switches into anaerobic decomposition which causes the formation of H2S compounds. This study aims to knowing differences in sediment organic materials and H2S within and adjacent of mangrove areas and to determine the relation of H2S with sediment organic materials and dissolved oxygen in the mangrove areas of Bedono. Survey method is refered, and the study was conducted in May - June 2017 on locations representing mangrove areas and the surrounding environment. The data measured are water temperature, brightness, depth, current speed, dissolved oxygen, pH, sediment organic materials and H2S in the water. Sampling was conducted four times every fortnight. The result of the water temperature is  28-31 ° C, brightness 14.5 to 68 cm, 33-165 cm depth, current speed 0-0.1 m/s, dissolved oxygen 2-5,2 mg/l, pH 5-6, sediment organic material 7,73 to 20.27%, H2S 0.003 to 0.037 mg/l. Sediment organic materials and H2S were highest within the mangrove area, with an average 16.36% and 0.031 mg/l, and the lowest outside of mangrove area with an average 9.78% and 0.01 mg/l. H2S higher in the inside of  the mangrove areas compared to the outside of it. The relation of H2S with sediment organic materials and dissolved oxygen is linearly related according to the equation H2S= 0.027+ 0.001SOM- 0.006DO (r= 0.7246, SOM= Sediment Organic Materials, DO= Dissolved Oxygen).


2020 ◽  
Vol 28 (3) ◽  
pp. 311-324
Author(s):  
Pauliina A. Ahti ◽  
Anna Kuparinen ◽  
Silva Uusi-Heikkilä

Body size acts as a proxy for many fitness-related traits. Body size is also subject to directional selection from various anthropogenic stressors such as increasing water temperature, decreasing dissolved oxygen, fisheries, as well as natural predators. Changes in individual body size correlate with changes in fecundity, behaviour, and survival and can propagate through populations and ecosystems by truncating age and size structures and changing predator–prey dynamics. In this review, we will explore the causes and consequences of changing body size in fish in the light of recent literature and relevant theories. We will investigate the central role of body size in ecology by first discussing the main selective agents that influence body size: fishing, increasing water temperature, decreasing dissolved oxygen, and predation. We will then explore the impacts of these changes at the individual, population, and ecosystem levels. Considering the relatively high heritability of body size, we will discuss how a change in body size can leave a genetic signature in the population and translate to a change in the evolutionary potential of the species.


2009 ◽  
Vol 89 (6) ◽  
pp. 1109-1116 ◽  
Author(s):  
Hachem Ben Naceur ◽  
Amel Ben Rejeb Jenhani ◽  
Mohamed Salah Romdhane

In order to provide a better characterization and understanding of the brine shrimp Artemia salina life-cycle, different ecological and biological parameters were taken out monthly during two periods from November 2005 to April 2006 and from November 2006 to April 2007 in Sabkhet El Adhibet (south-east Tunisia). Variation of water temperature, salinity, pH, dissolved oxygen, nutrients (orthophosphate, nitrites, nitrates and ammonium) and phytoplankton density were monitored. The Artemia population was also surveyed. Artemia were present in the site with salinity between 32.2 and 281.7 g l−1 and water temperature between 12.1 and 25.4°C. The pH ranged from 7.6 to 9 and dissolved oxygen concentration from 3.4 to 17.5 mg l−1. Minimum and maximum values of phytoplankton density were 0.19 and 14.59 106 cell l−1. In addition, the nutrient analysis registered showed that nitrate and ammonium represent the major nutrient. The Artemia population density fluctuated between 0.22 and 38.57 individuals per litre. The male:female ratio was dominated by the males. Artemia from Sabkhet El Adhibet showed variability in fecundity (total offspring and brood size) as well as in the ratio encystment/oviviparity. The individual fecundity fluctuates between 29.4 and 70.2 cysts and 17.8 and 69.8 nauplii. Finally, the influence of physical and chemical parameters as well as phytoplankton density over the Artemia population was noticed.


2021 ◽  
Vol 61 ◽  
pp. e20216107
Author(s):  
Jose Ismael Rojas-Peña ◽  
Jesús Manuel Vásquez-Ramos ◽  
Luis Gonzalo Salinas-Jiménez ◽  
Diana Paola Osorio-Ramirez ◽  
Clara Inés Caro-Caro

The mayflies are insects widely known as indicators of aquatic quality in freshwater systems, they are abundant and diverse in tropical streams. In this study, it was determined the influence of physical, chemical and bacteriological characteristics on the Ephemeroptera assembly in a period of low precipitation in the Ocoa river of Meta department. There were 5,332 nymphs belonging to 4 families, 10 genera and 3 species. Three new genera records and one species are presented for Meta: Cloeodes, Zelusia, Lumahyphes and Americabaetis alphus. The genera Camelobaetidius and Varipes were found associated with conditions of contamination by organic matter and water mineralization. Likewise, Americabaetis, Thraulodes, Lumahyphes and Tricorythodes were associated with contamination conditions, especially with nitrites and nitrates. Nanomis, Cloeodes and Zelusia showed greater sensitivity to the contamination condition and were related to high percentages of dissolved oxygen in the water and they were in the sampling stations of the upper part in the river. It is important to mention that there were not Ephemeroptera in most of the stations associated with the urban area. That reflects their high sensitivity to polluting conditions at low precipitation period.


2020 ◽  
pp. 305-313
Author(s):  
Dina Nath Pandit ◽  
Punita Kumari ◽  
Sunita Kumari Sharma

A study was carried out to evaluate the ecology and diversity of the zooplankton of the Ganga River at Arrah from Bihar, India from January 2018 to December 2019. Varied physical and chemical parameters supporting the zooplankton and corresponding biodiversity indices were studied. The water temperature showed inverse correlation with pH, dissolved oxygen, whereas direct relationship with total alkalinity, hardness, chloride, nitrate and sulfate. A total of 23 genera of zooplankton belonging to 6 genera of Rotifera, 5 of Protozoa, 5 of Cladocera, 4 of Copepoda and 3 of Ostracoda were identified with a density from 2 to 213 ind./L. The analysis showed that density of zooplankton declined in post-monsoon and remained maximum in summer because of the various environmental and inflow characteristics of the water body. The density of zooplankton showed direct correlation with total alkalinity, hardness and chloride of water but inverse correlation with water temperature, pH and dissolved oxygen. Shannon-Weiner index, Margalef richness index, Pielou’s evenness index, Menhninick’s index and Simpson index were won’t to assess relation of water quality with zooplankton and limnological profile of the river. The diversity indices indicated moderate to high diversity of zooplankton and moderately polluted conditions of the river.


Author(s):  
Amita M Watkar ◽  

Soil, itself means Soul of Infinite Life. Soil is the naturally occurring unconsolidated or loose covering on the earth’s surface. Physical properties depend upon the amount, size, shape, arrangement, and mineral composition of soil particles. It also depends on the organic matter content and pore spaces. Chemical properties depend on the Inorganic and organic matter present in the soil. Soils are the essential components of the environment and foundation resources for nearly all types of land use, besides being the most important component of sustainable agriculture. Therefore, assessment of soil quality and its direction of change with time is an ideal and primary indicator of sustainable agricultural land management. Soil quality indicators refer to measurable soil attributes that influence the capacity of a soil to function, within the limits imposed by the ecosystem, to preserve biological productivity and environmental quality and promote plant, animal and human health. The present study is to assess these soil attributes such as physical and chemical properties season-wise.


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