Rotifers in the Niger River, Niger: diversity and abundance in relation to environmental parameters

2021 ◽  
pp. 1-12
Author(s):  
H Souley Adamou ◽  
B Alhou ◽  
M Tackx ◽  
F Azémar
Keyword(s):  
Environmental Parameters ◽  
Niger River ◽  
River Niger

Evidence of terrestrial organic carbon inputs on Niger Delta Sea Shelf

2021 ◽  
Vol 19 (3) ◽  
pp. 83-100
Author(s):  
M.U. Uzoegbu
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Niger Delta ◽  
Organic Nitrogen ◽  
Constant Ratio ◽  
Sedimentation Pattern ◽  
Δ13c Values ◽  
Shelf Sediments ◽  
Niger River ◽  
River Niger

The objective of this research is to determine the actual source of organic matter in the Niger Delta Sea Shelf (NDSS). Organic carbon (OC) and n-alkanes were investigated in the suspended matter (SM) and surfcial sediments of the Niger and Imo Rivers and the opposite Niger Delta Sea Shelf. Organic nitrogen and carbon isotope (δ13C) values were determined as additional parameters in the sediments. OC and n-alkane concentrations were highly variable. This variability was interpreted as the result of sources of materials from the inland basins and a complex sedimentation pattern involving the discharges of these two rivers. Using the constant ratio of high molecular weight odd n-alkanes to OC in both rivers, the estimated value of more than 70% of the OC preserved in shelf sediments were terrestrially-derived. This result was substantiated by the overall dominance of land-derived n-alkanes. A second approach using δ13C values and assuming binary dilution of riverine and marine OC led to the determined source of organic matter. Keywords: Organic carbon; δ13C; n-Alkanes; Niger River; Imo River; Niger Delta Sea Shelf. 

scholarly journals Endoparasites of fresh water fishes from rivers in Edo State, Nigeria

2021 ◽  
Vol 18 (4) ◽  
pp. 197-204
Author(s):  
E.C. Osimen ◽  
L.I. Anagha
Keyword(s):  
Fresh Water ◽  
Fish Species ◽  
Parasitic Infection ◽  
Infected Fish ◽  
Fish Parasites ◽  
Fish Samples ◽  
Edo State ◽  
Niger River ◽  
Camallanus Cotti ◽  
River Niger

Parasites of fish constitute one of the major problems to fish health. Parasites of fish have been a great concern since they often cause disease conditions in fishes. This study described the parasitic faunas of eight fresh water bodies in Edo state (Ikpoba river, Ogba river, Ujogba river, Niger river at Illushi, Obe river, Gelegele river, Niger river at Agenebode and Osomegbe river). The duration of fish sampling was from October, 2017 to November, 2017.The fish samples (whole catch sourced from fishermen) were collected for identification, morphometric analysis and examination for the presence of parasites. One-way ANOVA and Tukey Honest Test were used to compare the data among size classes at the level of p <0.05. Three orders (Lepidosirenformes, Siluriformes and Polyteriformes), eight families  (Protopteridae, Clariddidae, Channiddae, Polypterididae, Melapteridae, Clarotidae, Cichlidae and Lorcariidae) and fourteen genera were examined. The study had an overall prevalence of 25.34%. The highest prevalence of fish parasitic infection was recorded in Niger river along Agenebode. Overall, parasite taxa recovered were nematodes (65.50%), trematodes (27.00%), cestodes (4.27%) and acanthcephalans (3.27%). The most infected fish species was Clarias gariepenus (13.77%). The helminth taxa (nematodes) had the highest prevalence of parasites (65.50%). The largest number of parasites isolated was Camallanus cotti (30.43%) and Procamallanus laevionchus (17.39%). This study showed river Niger at Agenebode with most parasitic prevalence, nematodes as the most prevalent parasitic taxa and Clarias  gariepenus as the most infected fish species. Keywords: Edo state, Freshwater fishes, Fish parasites, Helminths, Parasite taxa, Nigeria

HUBUNGAN KEPADATAN BIVALVIA DENGAN PARAMETER LINGKUNGAN DI PESISIR TANJUNG PURA KABUPATEN BANGKA TENGAH

2020 ◽  
Vol 13 (2) ◽  
pp. 112-121
Author(s):  
Sudiyar . ◽  
Okto Supratman ◽  
Indra Ambalika Syari
Keyword(s):  
Negative Impact ◽  
Principal Component ◽  
Environmental Parameters ◽  
Data Retrieval ◽  
Distribution Patterns ◽  
Random System ◽  
System Method ◽  
Relationship Of ◽  
The Relationship ◽  
Anadara Granosa

The destructive fishing feared will give a negative impact on the survival of this organism. This study aims to analyze the density of bivalves, distribution patterns, and to analyze the relationship of bivalves with environmental parameters in Tanjung Pura village. This research was conducted in March 2019. The systematic random system method was used for collecting data of bivalves. The collecting Data retrieval divided into five research stasions. The results obtained 6 types of bivalves from 3 families and the total is 115 individuals. The highest bivalve density is 4.56 ind / m², and the lowest bivalves are located at station 2,1.56 ind / m²,  The pattern of bivalve distribution in the Coastal of Tanjung Pura Village is grouping. The results of principal component analysis (PCA) showed that Anadara granosa species was positively correlated with TSS r = 0.890, Dosinia contusa, Anomalocardia squamosa, Mererix meretrix, Placamen isabellina, and Tellinella spengleri were positively correlated with currents r = 0.933.

Recirculation versus flow-through rainbow trout laboratory Flavobacterium columnare challenge

2020 ◽  
Vol 139 ◽  
pp. 213-221
Author(s):  
C Birkett ◽  
R Lipscomb ◽  
T Moreland ◽  
T Leeds ◽  
JP Evenhuis
Keyword(s):  
Rainbow Trout ◽  
Environmental Parameters ◽  
Cumulative Effects ◽  
Flavobacterium Columnare ◽  
Replacement Rate ◽  
Bacterial Concentration ◽  
Water Replacement ◽  
Dose Concentration ◽  
Flow Through ◽  
And Control

Flavobacterium columnare immersion challenges are affected by water-related environmental parameters and thus are difficult to reproduce. Whereas these challenges are typically conducted using flow-through systems, use of a recirculating challenge system to control environmental parameters may improve reproducibility. We compared mortality, bacterial concentration, and environmental parameters between flow-through and recirculating immersion challenge systems under laboratory conditions using 20 rainbow trout families. Despite identical dose concentration (1:75 dilution), duration of challenge, lot of fish, and temperature, average mortality in the recirculating system (42%) was lower (p < 0.01) compared to the flow-through system (77%), and there was low correlation (r = 0.24) of family mortality. Mean days to death (3.25 vs. 2.99 d) and aquaria-to-aquaria variation (9.6 vs. 10.4%) in the recirculating and flow-through systems, respectively, did not differ (p ≥ 0.30). Despite 10-fold lower water replacement rate in the recirculating (0.4 exchanges h-1) compared to flow-through system (4 exchanges h-1), differences in bacterial concentration between the 2 systems were modest (≤0.6 orders of magnitude) and inconsistent throughout the 21 d challenge. Compared to the flow-through system, dissolved oxygen during the 1 h exposure and pH were greater (p ≤ 0.02), and calcium and hardness were lower (p ≤ 0.03), in the recirculating system. Although this study was not designed to test effects of specific environmental parameters on mortality, it demonstrates that the cumulative effects of these parameters result in poor reproducibility. A recirculating immersion challenge model may be warranted to empirically identify and control environmental parameters affecting mortality and thus may serve as a more repeatable laboratory challenge model.

Mapping Senegambia: Legacies of Ambition and the Failure of an Early Colonial Venture

2018 ◽  
Vol 11 (2) ◽  
pp. 212-231
Author(s):  
Sven Outram-Leman
Keyword(s):  
Eighteenth Century ◽  
West Africa ◽  
Senegal River ◽  
Colonial Expansion ◽  
Secure Access ◽  
Early Colonial ◽  
River Niger

Britain's short-lived Province of Senegambia (1765–1783) was part of an expansion effort in the region driven by a desire to secure access to the gum trade of the Senegal river. Drawing on Britain's knowledge of France's dealings with the Upper-Senegal region it was complemented by the adoption of French cartography, edited to illustrate a new colonial identity. It is argued here that there was an additional motive of developing closer contact with the African interior. This pre-dates the establishment of the African Association in 1788 and its subsequent and better-known expeditions to the River Niger. In contrast to the French, however, the British struggled to engage with the region. This paper approaches the topic from a perspective of cartographic history. It highlights Thomas Jeffery's map of ‘Senegambia Proper’ (1768), copied from Jean Baptiste Bourguingnon d'Anville's ’Carte Particuliére de la Côte Occidentale de l'Afrique' (1751) and illustrative of several obstacles facing both British map-making and colonial expansion in mid-eighteenth century Africa. It is argued that the later enquiries and map-making activities of the African Association, which were hoped to lead to the colonisation of West Africa, built upon these experiences of failure in Senegambia.

STRUCTURE AND DYNAMICS OF ENVIRONMENTAL PARAMETERS OF HUMAN INTESTINAL MICROBIOME IN DIFFERENT CLIMATIC AND ECOLOGICAL ZONES OF ST. PETERSBURG

2020 ◽  
pp. 31-36
Author(s):  
Bugero N.V. ◽  
Ilyina N.A. ◽  
Aleksandrova S.M.
Keyword(s):  
Environmental Parameters ◽  
Intestinal Microbiome ◽  
Ecological Niches ◽  
Horizontal Structure ◽  
Ecological Zones ◽  
Qualitative And Quantitative ◽  
Symbiotic Relationships ◽  
Structure And Dynamics ◽  
Quantitative Changes ◽  
Micro Organisms

In order to understand the structure and dynamics of symbiotic relationships of human intestinal biotope micro-organisms, taxonomic constancy indices, the degree of contagion of the biocenosis under study and floristic significance were investigated, which made it possible to detect qualitative and quantitative changes in the microecology of the biotope being studied in persons living in different ecologically heterogeneous territories of Saint Petersburg. The contagiosity index estimated the distribution of species in space. Persons living in the ecologically disadvantaged Kirov district of the city have been found to show a reliable increase in this indicator for the obligate microflora: bifido and lacto bacteria, intestinal columns and bacteroids, compared to the resort district, which is considered a relatively favourable area for residence. On the contrary, there has been a reliable decrease in this indicator in the group of opportunistic micro-organisms (fungi of the genus Candida, staphylococcus, clostridium, etc.), resulting in the liberation of ecological niches successfully occupied by transient flora. This ratio reveals an imbalance of participation in the horizontal structure of the intestine ecosystem of the main symbiotes and representatives of the transient flora. To analyse the structure of symbiotic relationships, the constancy indices that form the microflora of the individuals of the groups studied were investigated. The analysis of the data obtained suggested that the dominant species in both groups were optional-anaerobic bifido and lactobacteria and oblique-anaerobic bacteroids. It should be noted, however, that in the residents of the dysfunctional Kirovsky district, against the background of the reduced constancy of the normal flora, opportunistic micro-organisms have entered. The floral significance index was also declining in the obligate flora of this group and increased for opportunistic species. Thus, the study of the environmental characteristics of the intestinal biotope using different ecological parameters for persons living in different technogenic load regions of St. Petersburg has shown that in the Kirov district with an unfavourable environmental situation there are compensated qualitative and quantitative changes in the intestinal microbiocenosis, resulting in a change in the hierarchy in the overall structure of micro-organisms.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ДИНАМИКИ МИНЕРАЛЬНОГО ПИТАНИЯ РАСТЕНИЙ В СИСТЕМЕ «УДОБРЕНИЕ-ПОЧВА-РАСТЕНИЕ»

2020 ◽  
Vol 65 (6) ◽  
pp. 1219-1229
Author(s):  
В.А. Четырбоцкий ◽  
◽  
А.Н. Четырбоцкий ◽  
Б.В. Левин ◽  
◽  
...  
Keyword(s):  
Experimental Data ◽  
Temporal Dynamics ◽  
Plant Biomass ◽  
Environmental Parameters ◽  
Parametric Identification ◽  
Agricultural Crop ◽  
Parameter System ◽  
Plant Nitrogen ◽  
Rhizosphere Microorganisms ◽  
Nitrogen Phosphorus

A numerical simulation of the spatial-temporal dynamics of a multi-parameter system is developed. The components of this system are plant biomass, mobile and stationary forms of mineral nutrition elements, rhizosphere microorganisms and environmental parameters (temperature, humidity, acidity). Parametric identification and verification of the adequacy of the model were carried out based on the experimental data on the growth of spring wheat «Krasnoufimskaya-100» on peat lowland soil. The results are represented by temporal distributions of biomass from agricultural crop under study and the findings on the content of main nutrition elements within the plant (nitrogen, phosphorus, potassium). An agronomic assessment and interpretation of the obtained results are given.

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