scholarly journals Oil Pollution Effects on Nematodes in Mangrove Sediment: A Microcosm Study

Author(s):  
Gonasageran Naidoo ◽  
Krishnaveni Naidoo ◽  
Antoinette Swart

Abstract The effects of oil pollution on meiobenthic nematode assemblages in a mangrove sediment were investigated. Microcosms comprised 350 ml plastic jars that were filled with 200 g mangrove sediment and subjected to oiling, with or without addition of fertiliser. In the oiled treatments, 15 ml of Bunker fuel oil 180 and 5 ml/L fertiliser (N: P: K: 3: 2: 5) were added to the soil. After four weeks, nematodes were extracted and identified. In the unfertilised oiled treatment, nematode abundance and species richness were significantly reduced by 87% and 53%, respectively, compared to the control. In the fertilised oiled treatment, nematode abundance and species richness increased by 56% and 30% respectively. The eight taxa present in the control but absent in the oiled treatments (Monhystera, Prodesmodora, Plectus, Rhabditis, Koerneria, Rotylenchus, Tobrilus, and Fictor) were characterised as oil-intolerant. The seven taxa present in the oiled treatments (Monhystera, Ethmolaimus, Panagrolaimus, Camacolaimus, Hemicycliophora typica, and H. ripa and a species of the family Xyalidae) were characterised as oil-tolerant and resilient. In all treatments, the dominant species was Ethmolaimus. Taxa such as Rhabditis, Koerneria and Rotylenchus survived oiling, due to the addition of fertiliser. Fertilizer amendment favoured survival of Rhabditis, Koerneria and Rotylenchus and increased reproduction in Camacolaimus.

Two medium-scale ecosystems (mesocosms) were built on the Oslofjord: one a hard-bottom intertidal system and the other a subtidal soft-sediment system. The hard-bottom mesocosm consists of four basins, two controls and two which were dosed with diesel-oil (129 μg 1 -1 a high oil (HO) dose and 29 μg 1 -1 a low oil (LO) dose). Both oil doses caused high mortality of Mytilus edulis and growth was reduced in the macroalgae Ascophyllum nodosum and Laminaria digitata . Recruitment of Littorina littorea was also affected by oil so that populations declined over time. Subtidal benthic communities have been established in the mesocosm and show variations in sediment chemistry within the range found in the field. Although recruitment of benthic macrofauna is reduced, dominant species and species structure remain closely similar to that in the field over six months. Bioturbation effects studied in the mesocosm have shown the important influence of large, rare species in structuring benthic communities, a finding which would not be possible in nature by diving or by the use ofsubmersibles. Preliminary results from a community taken from 200 m depth and established in the mesocosm suggest that it is now possible to do detailed manipulation experiments on communities simulating the whole continental shelf.


Author(s):  
Jose L. Rueda ◽  
Manuel Fernández-Casado ◽  
Carmen Salas ◽  
Serge Gofas

The macrofauna of molluscs associated with soft bottoms in the Bay of Cádiz (southern Spain) was studied monthly from February 1994 to January 1996. The number of species (63) is high for a soft bottom and is related to environmental characteristics (growth of macrophytes) and the biogeographical setting of the studied area. Corbula gibba (∼90%) was the dominant species in this taxocoenosis together with the gastropod Nassarius pygmaeus and the bivalves Pandora inaequivalvis, Parvicardium exiguum and Macoma melo. The most frequent species during the two years was also the bivalve Corbula gibba (100%) followed by the gastropods Nassarius pygmaeus, Tricolia tenuis, Rissoa membranacea and the bivalve Macoma melo. Total abundance of the taxocoenosis in both years reached higher values in spring. The dynamics of the ecological indices such as diversity or evenness, and the species richness showed a similar pattern in both years, with low values of diversity and evenness together with high species richness in spring and summer months and the reverse in autumn and winter. The qualitative correspondence analysis of monthly samples shows an ordination related to seasonality in both studied years, however the values of Jaccard's coefficient do not indicate significant boundaries among the monthly samples. The quantitative correspondence analysis shows an ordination and grouping of samples related to the biology of species, particularly with the recruitment of C. gibba, the dominant species. The existence of similar trends in the structure of the taxocoenoses over both years, and the seasonality highlighted by the qualitative correspondence analysis, seems to indicate a certain stability of the ecosystem.


2016 ◽  
Vol 16 (3) ◽  
Author(s):  
Felipe Augusto Trindade Gondim-Silva ◽  
Alessandra Rodrigues Santos Andrade ◽  
Rafael Oliveira Abreu ◽  
Jamile Santos Nascimento ◽  
Geovane Paixão Corrêa ◽  
...  

Abstract The Conde municipality is located in the northern coast of the state of Bahia (NC), northeastern Brazil, and is part of the Atlantic Tropical domain. The anuran fauna of the northern portion of the NC is still poorly known if compared to the southern portion. The Restinga is one of the predominant environments of the coastal plains of the NC and it is characterized essentially by presenting sandy soil covered by herbaceous and shrubby vegetation. The objective of this study was to determine the anuran species composition and diversity for the Restinga of the Conde municipality. Sampling was carried out at night by active search over four periods of five consecutive days each, two over the 'main rainy season' and two in a 'lesser rainy season', using 14 sample units (SUs) and five extra sample plots (EPs). We calculated dominance and species diversity using the Berger-Parker and Shannon-Wiener H' indices, respectively. We used accumulation curves and the Jackknife 1 estimator to estimate anuran species richness, considering only the data obtained from the SUs. We recorded 713 anuran specimens distributed within 33 species, 13 genera and five families (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae and Microhylidae). The Hylidae and Leptodactylidae families had the highest species richness. Considering only the SUs (Jackknife 1 estimator in brackets), we recorded 28 species in the study area (33.9 ± 2.3), 13 in Shrubby Vegetation Zones - SVZ (20.8 ± 2.9) and 25 in Freshwater Wetland Zones - FWZ (28.9 ± 1.9). The abundance and species diversity of the FWZ (n = 638 specimens; H'= 2.4) were higher than those recorded for the SVZ (n = 52 specimens; H' = 1.9). The SVZ and FWZ showed distinct dominant species, wherein Pristimantis paulodutrai was the dominant species in SVZ and Scinax fuscomarginatus in FWZ. The Restinga of the Conde municipality stands out as the one with the highest anuran species richness already recorded considering only SVZ and FWZ. Moreover, its anuran species composition represented 55% of the anuran species known for the NC and included taxa common to three different morphoclimatic domains (Tropical Atlantic, Cerrado and Caatinga).


Biologia ◽  
2017 ◽  
Vol 72 (2) ◽  
Author(s):  
Irena Bielańska-Grajner ◽  
Tomasz Mieczan ◽  
Anna Cieplok

AbstractPeat bogs play key roles in preserving the stability of ecological relationships, but are some of the fastest disappearing and most endangered ecosystems in Europe. The aims of this study were: (1) to compare the distribution, species richness, diversity, and density of rotifers in microhabitats of a raised bog; and (2) to verify the hypothesis that rotifer density and species composition are dependent on seasonal factors, moss moisture content, and the dominant species of mosses in the microhabitats. Sampling was done monthly from April to November in 2013–2014 in the bog Moszne in eastern Poland (51°27′28.7″ N, 23°07′15.8″ E). The microhabitats sampled included hummocks, slopes, and hollows. A total of 40 rotifer taxa were identified. The highest species richness occurred in the hollows (40), dominated by


Diversity ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 196 ◽  
Author(s):  
Ahlem Maamar ◽  
Marie-Elisabeth Lucchesi ◽  
Stella Debaets ◽  
Nicolas Nguyen van Long ◽  
Maxence Quemener ◽  
...  

While over hundreds of terrestrial fungal genera have been shown to play important roles in the biodegradation of hydrocarbons, few studies have so far focused on the fungal bioremediation potential of petroleum in the marine environment. In this study, the culturable fungal communities occurring in the port of Oran in Algeria, considered here as a chronically-contaminated site, have been mainly analyzed in terms of species richness. A collection of 84 filamentous fungi has been established from seawater samples and then the fungi were screened for their ability to utilize and degrade crude oil. A total of 12 isolates were able to utilize crude oil as a unique carbon source, from which 4 were defined as the most promising biodegrading isolates based on a screening test using 2,6-dichlorophenol indophenol as a proxy to highlight their ability to metabolize crude oil. The biosurfactant production capability was also tested and, interestingly, the oil spreading and drop-collapse tests highlighted that the 4 most promising isolates were also those able to produce the highest quantity of biosurfactants. The results generated in this study demonstrate that the most promising fungal isolates, namely Penicillium polonicum AMF16, P. chrysogenum AMF47 and 2 isolates (AMF40 and AMF74) affiliated to P. cyclopium, appear to be interesting candidates for bioremediation of crude oil pollution in the marine environment within the frame of bioaugmentation or biostimulation processes.


Author(s):  
O. A. Odintsev ◽  
◽  
A. A. Odintseva ◽  

The materials of year-round bird counts conducted by the authors in Omsk from September 2006 to Au-gust 2009 in nine habitats, as well as on the territory of four municipal districts of the Omsk Province from June 1 to August 10, 2020 have been analyzed. The species richness was studied, the analysis of the species numbers and distribution was carried out, and the abundance of Motacillidae on the territory of the studied administrative districts is indicated. Species sketches are given, in the compilation of which special attention is paid to the nature and duration of stay, as well as the distribution of birds by habitat. It was found that the encountered representatives of this family inhabit all studied biotopes, but some spe-cies are not evenly distributed.


1991 ◽  
Vol 26 (1) ◽  
pp. 843-851
Author(s):  
Tadahiko Kurosawa ◽  
Mikio Honda ◽  
Kaname Tanaka ◽  
Eiichi Nakajima ◽  
Hiroshi Amatu

Hacquetia ◽  
2021 ◽  
Vol 20 (1) ◽  
pp. 217-224
Author(s):  
Károly Penksza ◽  
Péter Csontos ◽  
Gergely Pápay

Abstract Festucetum vaginatae Rapaics ex Soó 1929 em. Borhidi 1996 is a characteristic association of the calcareous sandy areas of the Pannonian basin; its dominant grass species is Festuca vaginata. Another typical species of these sandy areas is the newly discovered F. pseudovaginata. The question is whether F. pseudovaginata forms an independent coenotaxa? Our study proved that F. vaginata and F. pseudovaginata populations grow separately and compose different associations. Stands dominated by F. pseudovaginata had a higher species richness and harboured twice as many Festuco-Brometea species compared to the Festucetum vaginatae stands. Diagnostic species of the Festucetum pseudovaginatae association are Festuca pseudovaginata, Colchicum arenarium, Ephedra distachya, Koeleria majoriflora, and Astragalus onobrychis. The number of species, the density of the individuals, and the variability and diversity of the vegetation separated it from the Festucetum vaginatae association; thus, it can be considered an independent endemic association. Festucetum pseudovaginatae has its own differentiating and dominant species: Carex stenophylla, Cynodon dactylon, Eryngium campestre, Kochia laniflora.


2009 ◽  
Vol 83 (5) ◽  
pp. 750-766 ◽  
Author(s):  
M. G. Harasewych ◽  
Anton Oleinik ◽  
William Zinsmeister

Leptomaria antipodensis and Leptomaria hickmanae are described from the Upper Cretaceous [Maastrichtian] Lopez de Bertodano Formation, Seymour Island, and represent the first Mesozoic records of the family Pleurotomariidae from Antarctica. Leptomaria stillwelli, L. seymourensis, Conotomaria sobralensis and C. bayeri, from the Paleocene [Danian], Sobral Formation, Seymour Island, are described as new. Leptomaria larseniana (Wilckens, 1911) new combination, also from the Sobral Formation, is redescribed based on better-preserved material. The limited diversity of the pleurotomariid fauna of Seymour Island is more similar to that of the Late Cretaceous faunas of Australia and New Zealand in terms of the number of genera and species, than to the older, more diverse faunas of South America, southern India, or northwestern Madagascar, supporting the status of the Weddelian Province as a distinct biogeographic unit. The increase in the species richness of this fauna during the Danian may be due to the final fragmentation of Gondwana during this period.


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