scholarly journals Variability in the zooplankton assemblages in relation to environmental variables in the tidal creeks of Sundarban estuarine system, India

Author(s):  
Sanghamitra Basu ◽  
Pranab Gogoi ◽  
Subarna Bhattacharyya ◽  
Lohith Kumar K. ◽  
Sanjoy Kumar Das ◽  
...  

Abstract The present study illustrates a holistic account of zooplankton community dynamics in relation to physico − chemical variables in the tidal creeks of Indian Sundarbans estuarine system. Out of 11 water parameters, seven parameters (Temp., salinity, DO, turbidity, PO4 − P, NO3 − N and NO2 − N) differed significantly (p ≤ 0.05) among seasons. A total of 63 zooplankton taxa were recorded with the predominance of Copepoda, varying in ranges from 59.55 to 73.13% of the total zooplankton population. PERMANOVA design depicted the significant variations of zooplankton population both spatially (F = 2.313; p = 0.001) and temporally (F = 6.107; p = 0.001). Out of 41 species of Copepoda recorded, 14 species (Paracalanous parvus, Parvocalanous dubia, Bestiolina similis, Acrocalanous gibber, A. gracilis, Acartia erythraea, A. spinicauda, Pseudodiaptomus serricaudatus, P. annandalei, P. aurivilli, Oithona brevicornis, O. similis, Longipedia weberi and Microsetella norvegica) indicated as ‘characterizing species’ in the creek environment, and highlighted the euryhaline nature as well as broad range of thermal tolerance of these species. β – diversity index (Index of Multivariate dispersion) reflected higher values (β = >1) in the creeks (S4, S2 and S6), those are experienced with high anthropogenic pressure. On the whole, the calculated mean value of α − diversity (dʹ=4.07; H'=2.31) indicated ‘good’ zooplankton diversity. Water parameters viz., Temp., salinity, DO, turbidity, PO4 − P and NO3 − N were found to have influence on the distribution, abundance and diversity of zooplankton in the creeks. More specifically, the linear model (DistLM) exhibited two variables viz., temperature and salinity were the primary controlling factors in shaping the zooplankton community compositions in the creek environment.

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1924 ◽  
Author(s):  
Napiórkowski ◽  
Bąkowska ◽  
Mrozińska ◽  
Szymańska ◽  
Kolarova ◽  
...  

The zooplankton community structure and diversity were analysed against the gradient of floodplain lakes connectivity and water level under different flood-pulse dynamics in the Vistula River. The lakes differed in terms of hydrology, among others in the degree/type of their connection with the river (permanent, temporary and no connection). The study was conducted during the growing seasons in the years 2006–2013 and involved the lower Vistula River and three floodplain lakes: isolated, transitional and connected. Water samples were collected biweekly from April to September. Zooplankton was the most diverse and abundant in the transitional lake (the highest Shannon α-diversity index H’ and Pielou’s evenness index J’). The gentle washing of the lakes might have stimulated the development of zooplankton in accordance with the Intermediate Disturbance Hypothesis. The diversity and density of zooplankton were higher in the connected lake compared to the isolated one. We confirmed the hypothesis that zooplankton should be more abundant and diverse in floodplain lakes connected with the river (or transitional) than in isolated ones. Zooplankton analyses indicated that hydrological conditions (flood-pulse regime) contributed most substantially to zooplankton diversity and density in the floodplain lakes of the lower Vistula valley.


2020 ◽  
Vol 29 (1) ◽  
pp. 25-34
Author(s):  
Charly Oumarou Ngoute ◽  
Sévilor Kekeunou ◽  
Michel Lecoq ◽  
Armand Richard Nzoko Fiemapong ◽  
Philène Corine Aude Um Nyobe ◽  
...  

Grasshoppers are highly diversified in tropical rainforests and considered of both ecological and conservation importance. The population dynamics of central African grasshoppers, however, and the structure of their communities remain poorly studied. We report here on the impact of human activities on the diversity of grasshopper species from three localities in southern Cameroon: Ongot, more anthropized forest; Zamakoe, moderately anthropized forest; and Ngutadjap, less anthropized forest. Data were collected using sweep nets, quadrats, and pitfall traps. We analyzed how pressures from human activities affected the grasshopper species compositions using five statistical methods: (1) two non-parametric estimators for specific richness, (2) abundance, (3) abundance distribution model, (4) α diversity index, and (5) β diversity index. The results showed no significant differences in species richness between the sites (nine species at Zamakoe, seven each at Ongot and Ngutadjap). Among these species, one was specific to Ongot and Zamakoe, while one, two, and three species, respectively, were found only in Ongot, Ngutadjap, and Zamakoe. Abundance and species diversity of grasshoppers increased with anthropogenic pressure on the forests. We noticed a great similarity between the grasshopper communities of the two localities under the greatest anthropogenic pressure (Ongot and Zamakoe) compared to that of the less anthropized locality of Ngutadjap. The most common grasshopper species, Mazea granulosa, was most abundant where deforestation was highest. Species diversity was highest in the more and moderately anthropized forests, and the diversity index showed greater similarity between these two grasshopper communities compared with that of the less anthropized forest. This work enables us to better understand how the parameters of these insect communities reflect the degree of forest degradation in southern Cameroon.


2011 ◽  
Vol 101 (1-2) ◽  
pp. 75-84 ◽  
Author(s):  
Juliana D Dias ◽  
Érica M Takahashi ◽  
Natália F Santana ◽  
Cláudia C Bonecker

We investigated the impact of fish cage culture on the zooplankton community structure in a tropical reservoir. We hypothesized that community abundance is greater near cages and increases over time due to the increase in food availability. Samplings were performed near, upstream and downstream from net cages, and before and after net cage installation. The abundance of zooplankton increased 15 days after the experiment was set up, followed by a reduction and finally increased. Rotifer abundance showed significant differences among sites (p<0.05) and sampling periods (p<0.001). Significant differences were also observed in total zooplankton and cladoceran abundance (p<0.001). The spatial and temporal variation of the physical and chemical variables were indirectly correlated with the structure and dynamic of the zooplankton community, as they indicated the primary production in the environment. Our hypothesis was rejected, since the zooplankton was abundant at the reference site. Only rotifers showed higher abundance near cages, due to the influence of food availability. Community dynamics during the experiment was also correlated to food availability. Our results suggest an impact of fish farming on the zooplankton community.


2013 ◽  
Vol 14 (3) ◽  
pp. 32 ◽  
Author(s):  
E. CHALKIA ◽  
G. KEHAYIAS

A one year investigation of the zooplankton community composition and dynamics in Lake Οzeros (western Greece) revealed 25 invertebrate species (16 rotifers, three copepods, five cladocerans and one mollusc larva). The mean zooplankton abundance fluctuated between 59.4 to 818 ind l-1, having maximum values in spring. The species composition and seasonal variation do not differentiate Lake Ozeros from the nearby lakes. The presence of the dominant calanoid copepod Eudiaptomus drieschi and some of the rotifer species recorded are characteristics of either oligo- or eutrophic lakes. According to the trophic state index (TSI) Lake Ozeros is a meso-eutrophic ecosystem, in which the eutrophic character was possibly the result of the high charge with phosphorus (being raised by 28.9 % in comparison to previous decades), which came into the lake via the surrounding agricultural cultivations and mainly the pig-raising activities. In contrast, the concentrations of ΝΟ3, ΝΟ2 and NH4 have considerably decreased possibly due to the termination of the tobacco cultivations around the lake during the last years. The novel information on the abiotic and especially the biotic elements of Lake Ozeros provided by the present study can contribute to the effective management of this aquatic ecosystem in the future.


Author(s):  
Pema Lhamo ◽  
Ahmedul Kabir ◽  
Sayed Mohammad Nazim Uddin

Plant diversity in the wetlands of Phobji and Gangtey represents an important aspect of the overall wetland ecosystem. However, over the years, the increasing trend in population has initiated the building of many infrastructures and accommodations which lie at close proximity to the core wetland area. The plant diversity in human settled area and core undisturbed area was studied, with an objective to assess the influence of human settlement on the plant diversity. A belt transect method was used for the purpose of vegetation survey and Shannon Wiener diversity was calculated using the relative dominance. Plants were analyzed for their diversity, richness, dominance and invasive nature. Additionally, soil and water parameters were also tested to see the current situation of the pH and nutrient levels. A total of 136 species belonging to 39 families was identified in both the areas. The overall diversity index and species richness was found to be higher in the undisturbed areas. Soil analysis did not show much of a difference in physical and chemical parameters except for a slight difference in potassium content. Similarly, water parameters did not show much difference but only showed variation in calcium content. The findings of the study indicated towards the increasing influence of human settlement in the wetland.


2017 ◽  
Vol 12 (1) ◽  
pp. 190-199 ◽  
Author(s):  
Elzbieta Krolak ◽  
Krzysztof Lewandowski ◽  
Zbigniew Kasprzykowski

AbstractThe effect of heated waters from coal-burning power stations on the water parameters and the occurrence of macroinvertebrates depends on the individual characteristics of the river to which the heated waters are discharged. The objective of the study was to assess the impact of heated water from the Ostrołęka Power Station on selected water properties and the macroinvertebrate community in the Narew River. Samples were collected in years: 2013-2016 along two river stretches: upstream and downstream of the canal. The water temperature was higher and the oxygen concentrations were lower at the downstream sites compared to the upstream sites of the canal. The values of conductivity, concentrations of nitrates, phosphates, chlorides and calcium were similar at the sampling sites. A total of 33 families of macrozoobenthos were found. The numbers of families were positively correlated with the temperature and conductivity and negatively correlated with oxygen. The heated waters were found to have no effect on the Shannon-Wiener diversity index. The inflow of heated waters increased the percentage of Gammaridae, represented by species Dikerogammarus haemobaphes (Eichwald, 1841) and decreased the percentage of Chironomidae. The presence of the thermophilous bivalve Sinanodonta woodiana (Lea, 1934) was noted downstream of the canal.


2017 ◽  
Vol 3 (1) ◽  
pp. 123
Author(s):  
Putu Satya Pratama ◽  
Dwi Budi Wiyanto ◽  
Elok Faiqoh

Seagrass has function as nursery ground, spawning ground, feeding ground and habitat for many coastal organism (benthic, fish and epiphytes). Tourism activities in Sanur beach, the habitat of seagrass, could change the water condition, it indirectly influencing the existences of seagrass plants and periphyton in Sanur beach. The aim of this study are to analyze community structure of periphyton on seagrass leaves (Thalassia hemprichii and Cymodocea rotundatta) and its relationship with water parameters in four stations at Sanur beach area that has the unique characteristics. Water parameters measured were temperature, salinity, DO (Dissolved oxyen), pH, nitrate, phosphate, and TSS (Total Suspended Solid). Data analysis using PCA (Principal Component Analysis) to see the parameters that most influence on the abundance of periphyton. The results showed diversity index (H’) of periphyton is moderate, eveness index (E) moderate to high, and dominance index (C) is low to medium. It concluded that conditions of Sanur waters is stable but it is easily changed due to anthropogenic influences. PCA analysis showed that the parameters of the water have different effects on the abundance of periphyton at each seagrass leaves. Periphyton on Thalassia hemprichii was influenced by TSS, while Cymodocea rotundatta was influenced by phosphate, nitrate, temperature, DO, and TSS.


2019 ◽  
Vol 5 (2) ◽  
pp. eaau8317 ◽  
Author(s):  
Peng Zheng ◽  
Benhua Zeng ◽  
Meiling Liu ◽  
Jianjun Chen ◽  
Junxi Pan ◽  
...  

Schizophrenia (SCZ) is a devastating mental disorder with poorly defined underlying molecular mechanisms. The gut microbiome can modulate brain function and behaviors through the microbiota-gut-brain axis. Here, we found that unmedicated and medicated patients with SCZ had a decreased microbiome α-diversity index and marked disturbances of gut microbial composition versus healthy controls (HCs). Several unique bacterial taxa (e.g., Veillonellaceae and Lachnospiraceae) were associated with SCZ severity. A specific microbial panel (Aerococcaceae, Bifidobacteriaceae, Brucellaceae, Pasteurellaceae, and Rikenellaceae) enabled discriminating patients with SCZ from HCs with 0.769 area under the curve. Compared to HCs, germ-free mice receiving SCZ microbiome fecal transplants had lower glutamate and higher glutamine and GABA in the hippocampus and displayed SCZ-relevant behaviors similar to other mouse models of SCZ involving glutamatergic hypofunction. Together, our findings suggest that the SCZ microbiome itself can alter neurochemistry and neurologic function in ways that may be relevant to SCZ pathology.


2017 ◽  
Vol 78 ◽  
pp. 141-168 ◽  
Author(s):  
Ursula A. Howson ◽  
Gary A. Buchanan ◽  
James A. Nickels

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