scholarly journals Impacts of Anthropogenic Stressors on Hydrochemistry, Benthic Macroinvertebrates and Sediment Characteristics of the Lagos Lagoon, Nigeria

2021 ◽  
Vol 25 (8) ◽  
pp. 1349-1356
Author(s):  
O.F. Fasuyi ◽  
W.A. Yusuf ◽  
J.A. Nkwoji
Keyword(s):  
Benthic Macroinvertebrates ◽  
Total Population ◽  
Benthic Fauna ◽  
Sediment Characteristics ◽  
Sediment Grain Size ◽  
Anthropogenic Stressor ◽  
Lagos Lagoon ◽  
Capitella Capitata ◽  
Number Of Individuals

The anthropogenic impact on the water, benthic macroinvertebrates and sediment grain size of Lagos lagoon was investigated between July and October, 2019. Ten sampling stations were selected based on their importance as likely sources of different forms of anthropogenic stressor to the lagoon. Water temperatures, pH and salinity were measured in situ. Water and benthic samples were collected monthly and analysed using standard methods. Nutrient levels were determined using a spectrophotometer. The hydrochemistry of the stations differed significantly (p<0.05) with the exception of temperature and pH. The sediment grains across the study stations consists basically of sand and mud, with sand dominating the grain type. A total of 502 individuals comprising 3 phyla, 4 classes, 10 families and 11 species was recorded. The phylum mollusca which contributed 92% to the total number of individuals was represented by two Classes; Gastropoda and Bivalvia, with the gastropod Tympanotonus fuscatus having the highest number of individuals (321). Thephylum Annelida represented by one Class, Polychaeta and two Species Nereis sp. and Capitella capitata contributed 6% to the total number of individuals. The class Crustacea, representing the Phylum Arthropoda was the least sampled (7 individuals) constituting about 1.4% of the total population Result showed that different pollution sources have negatively impacted the water chemistry of the lagoon and reduced the diversity and abundance of its benthic macroinvertebrates community. The sedentary nature of this group of benthic fauna could be the major reason why they are most impacted.

scholarly journals Do the assemblages of benthic macroinvertebrates in nearshore waters of Western Australia vary among habitat types, zones and seasons?

2005 ◽  
Vol 85 (2) ◽  
pp. 217-232 ◽  
Author(s):  
M.D. Wildsmith ◽  
I.C. Potter ◽  
F.J. Valesini ◽  
M.E. Platell
Keyword(s):  
Species Composition ◽  
Benthic Macroinvertebrates ◽  
Habitat Type ◽  
Abundant Species ◽  
Subtidal Zone ◽  
Habitat Types ◽  
Environmental Characteristics ◽  
Deposit Feeding ◽  
Number Of Individuals

Benthic macroinvertebrates were sampled seasonally in the subtidal and upper and lower swash zones at two sites in each of six nearshore habitat types on the lower west coast of Australia. The habitat types, which differed mainly in the extent of their exposure to wave activity and whether sea grass and/or nearshore reefs were present, had been distinguished quantitatively using values for a suite of seven statistically-selected enduring environmental characteristics (Valesini et al., 2003). The core samples yielded 121 species representing eight phyla, among which the Polychaeta, Malacostraca and Bivalvia were the most speciose classes, contributing ∼38, 23 and 10%, respectively, to the total number of individuals. The total number of species and mean density of macroinvertebrates at the most protected habitat type (1), i.e. 70 and 209·2 individuals 0·1 m−2, respectively, were far greater than in any other habitat type. Habitat type influenced species composition to a greater extent than either zone or season. Furthermore, the extents of the differences among the species compositions of the six habitat types statistically matched the extents of the differences among the values for the suite of enduring environmental characteristics that distinguished each of those habitat types. Overall, the species composition at habitat type 1 was the most distinct, containing five abundant species of polychaetes that were adapted to deposit-feeding in calm waters with high levels of organic material and which were rare in all other habitat types. In contrast, the fauna at the most exposed habitat type was characterized by four crustacean species and a species of bivalve and polychaete, whose mobility and tough external surface facilitated their survival and feeding in turbulent waters. The zonal differences in faunal compositions among habitat types were greatest in the case of the subtidal zone. The faunal compositions differed among zones and seasons only at the most protected habitat type.

scholarly journals COVID-19 attack ratio among children critically depends on the time to removal and activity levels

2021 ◽  
Author(s):  
Jianhong Wu ◽  
Nicola Luigi Bragazzi ◽  
Francesca Scarabel ◽  
Zachary McCarthy ◽  
Jummy David ◽  
...  
Keyword(s):  
Total Population ◽  
Vaccine Coverage ◽  
Herd Immunity ◽  
Activity Levels ◽  
Rapid Testing ◽  
Dynamics Model ◽  
Canadian Population ◽  
Social Mixing ◽  
Number Of Individuals ◽  
The Relationship

The attack ratio in a subpopulation is defined as the total number of infections over the total number of individuals in this subpopulation. Using a methodology based on modified age-stratified transmission dynamics model, we estimated the attack ratio of COVID-19 among children (individuals 0-11 years) in Ontario, Canada when a large proportion of individuals eligible for vaccination (age 12 and above) are vaccinated to achieve herd immunity among this subpopulation, or the effective herd immunity with additional physical distancing measures (hence effective herd immunity). We describe the relationship between this attack ratio among children, the time to remove infected individuals from the transmission chain and the children-to-children daily contact rate, while considering the increased transmissibility of virus variants (using the Delta variant as an example). We further illustrate the generality and applicability of the methodology established by performing an analysis of the attack ratio of COVID-19 among children in the Canadian population. The clinical attack ratio, the number of symptomatic infections over the total population can be informed from the attack ratio, and both can be reduced substantially via a combination of higher vaccine coverage in the vaccine eligible population, reduced social mixing among children, and rapid testing and isolation.

Beetal goats in their native tract

2001 ◽  
Vol 31 ◽  
pp. 65-74
Author(s):  
M.S. Tantia ◽  
P.K. Vij ◽  
G. Sahana ◽  
A. Jain ◽  
S.K. Prasad
Keyword(s):  
Milk Yield ◽  
Total Population ◽  
Flock Size ◽  
Low Input ◽  
Detailed Survey ◽  
Lactation Length ◽  
Poor Families ◽  
The Status

SummaryBeetal is one of the largest Indian breeds of goats bred mainly for milk but equally important for meat as well. This breed is found in Punjab along the Indo-Pakistani border. The status of the Beetal breed in its native tract was studied through a detailed survey in the Gurdaspur and Amritsar districts of Punjab. In this part of the country goats are mainly reared by ‘Sansi’ tribals who are landless. Goat flocks are mainly stationery and browsing is the main source of feed and fodder for these goats. Long drooping ears and roman nose are the typical characteristics of this breed. The total population of this breed in its native tract in 1997 was found to be 20 772 and the average flock size was 5.27. Average test day milk yield and lactation length were 1.8±0.79 kg and 161 days, respectively. Average ages at first kidding and kidding interval were 17.2 and 11.14 months, respectively. Prolificacy was fairly high with an average of 1.76 kids per kidding.Beetal goats are the mainstay for the landless poor families of this region and the breed needs to be conserved in its breeding tract. There is a need to popularize this breed through demonstration units to convince the farmers that this breed is sustainable under low input conditions. This will help in in-situ conservation of the Beetal breed.

scholarly journals Distribusi Foraminifera Bentonik Hidup dalam Hubungannya dengan Sedimen Dasar Laut di Selat Sumba, Nusa Tenggara Timur

2019 ◽  
Vol 20 (1) ◽  
pp. 17
Author(s):  
Purna Sulastya Putra ◽  
Septriono Hari Nugroho
Keyword(s):  
Benthic Foraminifera ◽  
Research Area ◽  
Carbonate Content ◽  
Sediment Characteristics ◽  
Coarse Silt ◽  
Sediment Grain Size ◽  
Sea Floor ◽  
Floor Surface ◽  
Sediment Types ◽  
Box Corer

Marine geological survey of Ekspedisi Widya Nusantara (EWIN) LIPI 2016 was conducted by using RV Baruna Jaya VIII in the Sumba Waters from 4 to 26 August 2016. One of the aim of this survey is to understand the sea floor surface sediment characteristics and its influence to the benthic foraminifera distribution. Seven sediment samples were collected from sea floor surface in Sumba Strait, at the different location and depth using grabbing method with box corer. The samples have analyzed for the foraminifera content, sediment grain size, organic matter and carbonate content, and chemical element by XRF method. The living benthic foraminifera distribution increase to the east of the research area, which have higher content of the organic material and Fe, Rb, Zr, Zn and Sr elements in the sediment. The benthic foraminifera distribution most abundance founded at the depth of 800-1000 m with sediment types are sandy coarse silt  to sandy very coarse silt.Keywords: Benthic foraminifera, distribution, sea floor sediment, Sumba Strait.

scholarly journals Polychaetes associated with decaying wood in Térraba mangrove, South Pacific, Costa Rica

2016 ◽  
pp. 61-74
Author(s):  
Jeffrey A. Sibaja-Cordero ◽  
Silvia Echeverría-Sáenz
Keyword(s):  
Costa Rica ◽  
Salinity Gradient ◽  
Benthic Fauna ◽  
Central American ◽  
Faunal Assemblage ◽  
Sediment Samples ◽  
Estuarine Zone ◽  
Decaying Wood ◽  
Number Of Individuals ◽  
Sand Bottom

The present study shows spatial patterns in the faunal assemblage of decaying wood and sediments, with emphasis on the polychaetes. The survey was executed across a salinity gradient in a tropical mangrove estuary of Costa Rica. To capture the organisms we analyzed decomposing logs found in the Térraba mangrove and sediment samples were taken with a corer in the sand bottom. Seven different phyla were found in the sediment samples. Of the 192 individuals found in the sediment samples, 18 were polychaetes belonging to nine families and 11 species. Analyses of decaying wood resulted in 2 564 individuals distributed in five phyla. Polychaetes accounted for 429 individuals belonging to eight families and 16 species. Although, polychaetes were more abundant in decaying wood, and their diversity was lower. The abundance of polychaetes in decaying wood was negatively correlated with the number of individuals of Mollusca, Hexapoda and Crustacea. A change in the composition of polychaetes in decaying wood was found along the salinity gradient of this estuarine zone. Dissimilarities in the composition of benthic fauna in decaying wood and sediments in the Térraba mangrove showed that biodiversity was increased by the microhabitats inside the mangrove forest. Finally, several genera or species of polychaetes are new records for Costa Rica and the Central American Pacific Coast.

scholarly journals Taxonomic Diversity and Structure of Benthic Macroinvertebrates of Taabo Lake (Basin of Bandama; Ivory Coast)

2020 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Yanick Djoman Tanon ◽  
Idrissa Adama Camara ◽  
Norbert Kouakou Kouadio ◽  
Lassina Doumbia ◽  
Allassane Ouattara ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Benthic Macroinvertebrates ◽  
Ivory Coast ◽  
Taxonomic Diversity ◽  
Diversity Indices ◽  
Quality Parameters ◽  
Lake Basin ◽  
Littoral Zones ◽  
Sampling Points

The taxonomic diversity and structure of benthic macroinvertebrates of Taabo Lake (Ivory Coast), from November 2017 to October 2018 were evaluated. Water quality parameters, such as temperature (T °C), water transparency (cm), dissolved oxygen (mg.L-1), pH, turbidity (NTU), electrical conductivity (EC, µS.cm-1) were measured in situ using a multi-parameter probe HANNA, from four sampling points (littoral and sub-littoral zones) in Taabo Lake. Benthic macroinvertebrates sampling were collected by using Van veen in stainless steel. A total of 63 benthic macroinvertebrates taxa belonging to 23 Families, 8 Orders, 2 Classes and 2 Phylums (Molluscs and Arthropods) were identified. The most abundant of benthic macroinvertebrates were Mesogastropoda (66%) represented in all sampling points. They were followed by Diptera (25%), Odonata (3%), Ephemeroptera (3%), Basommatophora (2%), Heteroptera (1%), Lepidoptera and Coleoptera (less than 1%). The values of diversity indices of benthic macroinvertebrates collected in Taabo Lake showed no significant variations between sampling points.

scholarly journals Benthic macrofauna of sandy intertidal zone at Santos estuarine system, São Paulo, Brazil

1991 ◽  
Vol 39 (1) ◽  
pp. 01-13 ◽  
Author(s):  
Thais Navajas Corbisier
Keyword(s):  
Community Structure ◽  
Sandy Beaches ◽  
Sao Paulo ◽  
Benthic Macrofauna ◽  
Estuarine System ◽  
São Paulo ◽  
Sediment Characteristics ◽  
Capitella Capitata ◽  
One Year ◽  
High Level

Species composition, faunal density, species diversity and zonation patterns of benthic macrofauna, as well as its relation to sediment characteristics were examined and compared in three sandy beaches on the polyhaline area at Santos estuarine system in the State of São Paulo. Samples were collected quarterly during one year (July/1977 - May/1978). Low, mean and high intertidal levels were sampled. Polyehaetes dominated the fauna, both in terms of numbers of species and numbers of individuals. The community structure of Ponta da Praia beach was characterized by high density, low diversity (H') and evenness (J'), due to the dominance of the spionid Scolelepis squamata. At Vicente de Carvalho the fauna was characterized by the dominance of the polyehaetes Laeonereis acuta and Capitella capitata and presented low density, high diversity and evenness. At Bertioga Channel, intermediate values were observed and the fauna was dominated by Scololepis squamata andLaeonereis acuta. The sediment texture was responsible for those figures, although some differences in diversity may be explained by differences in wave energy. The low number of crustaceans and molluscs suggests the effect of the estuarine pollution upon the fauna. The zonation pattern of both species distribution and community structure differed at the studied sites; it was not correlated with sediment characteristics which were relatively uniform down shore; however, the lowest diversity was observed at the high level in all sites.

A method for quantifying hand-net samples of stream invertebrates

1999 ◽  
Vol 50 (2) ◽  
pp. 179 ◽  
Author(s):  
R. Marchant ◽  
G. Hehir
Keyword(s):  
Additional Data ◽  
Total Population ◽  
P Value ◽  
Sampling Point ◽  
Stream Invertebrates ◽  
Quantitative Sampling ◽  
Removal Sampling ◽  
A Site ◽  
Number Of Individuals ◽  
Probability Of Capture

Quantitative sampling using a hand-net can be accomplished by taking three successive catches of invertebrates from the same point on the streambed. This is a form of removal sampling. By plotting the decline in number of individuals in each catch against the total previously caught, the total population at the sampling point can be estimated. From this, the probability of capture in a single catch (p) can be calculated. For Agapetus, other trichopteran, leptophlebiid, caenid and gripopterygid larvae from a site on a tributary of the Acheron River in southern Australia, p varied from 0.66 to 0.81. Additional data for a species of Gammarus from the Credit River in Ontario gave a p value of 0.67. In three successive catches the overall probability of capture exceeded 95% for all taxa, indicating that with this degree of effort most individuals present were caught.

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