Benthic mollusc assemblages in West Antarctica: taxa composition and ecological insights

2017 ◽  
Vol 68 (11) ◽  
pp. 2095 ◽  
Author(s):  
Sandra Gordillo ◽  
Mariano E. Malvé ◽  
Gisela Moran
Keyword(s):  
Diversity Index ◽  
Benthic Communities ◽  
Austral Summer ◽  
Trophic Groups ◽  
West Antarctica ◽  
Suspension Feeders ◽  
Deposit Feeders ◽  
Wiener Diversity Index ◽  
Mollusc Assemblages ◽  
Group Species

Although different studies in Antarctica have dealt with benthic communities, few studies have focused on molluscan assemblages and their ecology. During the austral summer of 2011, 17 stations between depths of 68.5 and 754m were sampled in West Antarctica using a demersal bottom trawl pilot net on board RV ARA Puerto Deseado. In all, 1848 specimens of shelled molluscs were recorded. Gastropods were the most diverse group (species richness=74) and bivalves were the most abundant (n=1344). Shannon–Wiener diversity index values ranged between 0.58 and 2.99, with great variation at different stations. Cluster analysis using the Bray–Curtis coefficient showed three distinct assemblages types: one dominated by suspension feeders; a second with representatives from different trophic groups, including suspension feeders, grazers, scavengers, predators and deposit feeders; and a third, more differentiated, with few taxa and dominated by deposit feeders. Finally, multivariate analysis suggests that bivalves were more sensitive to temperature, whereas gastropods were more sensitive to depth.

scholarly journals Long term changes and recent state of macrozoobenthic communities along the Bulgarian Black Sea coast

2000 ◽  
Vol 1 (1) ◽  
pp. 123 ◽  
Author(s):  
V. TODOROVA ◽  
T. KONSULOVA
Keyword(s):  
Black Sea ◽  
Diversity Index ◽  
Benthic Communities ◽  
Published Data ◽  
Anthropogenic Pressure ◽  
Number Of Species ◽  
Wiener Diversity Index ◽  
Black Sea Coast ◽  
Average Abundance ◽  
Sea Coast

The analysis of macrozoobenthic samples collected from 34 stations along the Bulgarian Black Sea shelf at depths ranging from 12 to 83 m yielded 103 taxonomic units. The average abundance established in the present study was over 5000 ind/m2 with nearly 70% dominance of the polychaetes. The number of species, Shannon-Wiener diversity index (H') and Pielou's evenness (J) were the lowest in Varna and Burgas bays, indicating that they are the most ecologically threatened areas along the Bulgarian Black Sea coast. The quantitative and qualitative data were compared to published data from the pristine period 1954-1957 and from the period 1982-1985 with intensive anthropogenic pressure. The comparison revealed an increase of the share of molluscan species and a decrease of the contribution of crustacean species in the total number of species. A 7-fold increase of the total average abundance was established compared to the pristine period 1954-1957. During the recent period the polychaetes are the most dominant group in the benthic abundance, while during the pristine period 1954-1957 the most abundant were the molluscs with nearly 61% of the total abundance. These changes in the benthic communities are attributed to the process of eutrophication. While in the pelagic environment signs of recovery have been observed, we deem that up to 1997 no such signs are valid for the benthic communities.

scholarly journals Bivalve mollusk assemblages on São Paulo's northern continental shelf, southeast Brazil

2005 ◽  
Vol 65 (4) ◽  
pp. 717-727 ◽  
Author(s):  
A. Soares-Gomes ◽  
A. M. S. Pires-Vanin
Keyword(s):  
Clustering Analysis ◽  
Biological Diversity ◽  
Permutation Test ◽  
Anthropogenic Activities ◽  
Austral Summer ◽  
Trophic Groups ◽  
Depth Gradient ◽  
Soft Bottom ◽  
Analysis Of Similarity ◽  
Mollusc Assemblages

Soft bottom bivalve mollusc assemblages were sampled along a depth gradient (10 to 100 m) on the northern São Paulo shelf during the austral summer and winter. A one-way analysis of similarity permutation test revealed there was no seasonal difference in the structure of the bivalve assemblages in the area. A clustering analysis indicated 3 groups of stations corresponding to the bathymetric gradient. Both K-dominance curves and Shannon and Pielou indexes showed higher biological diversity and higher evenness for the shallower area. Most of the bivalves found were classified as suspension-feeders, co-occurring with deposit-feeder species, suggesting an absence of negative interactions between these trophic groups. Differences in the frequency of disturbance along the depth gradient caused by wave storms - more common in winter - and also by predation and anthropogenic activities, such as dredging of fishing boats and input of gross sewage, likely explain the higher diversity found on the inner shelf of Ubatuba.

scholarly journals Effects of Plastic Debris on the Biofilm Bacterial Communities in Lake Water

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1465
Author(s):  
Chao Shen ◽  
Liuyan Huang ◽  
Guangwu Xie ◽  
Yulai Wang ◽  
Zongkai Ma ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Diversity Index ◽  
Plastic Substrate ◽  
Simpson Index ◽  
Plastic Debris ◽  
Plastic Substrates ◽  
Wiener Diversity Index

Increasing discharge of plastic debris into aquatic ecosystems and the worsening ecological risks have received growing attention. Once released, plastic debris could serve as a new substrate for microbes in waters. The complex relationship between plastics and biofilms has aroused great interest. To confirm the hypothesis that the presence of plastic in water affects the composition of biofilm in natural state, in situ biofilm culture experiments were conducted in a lake for 40 days. The diversity of biofilm attached on natural (cobble stones (CS) and wood) and plastic substrates (Polyethylene terephthalate (PET) and Polymethyl methacrylate (PMMA)) were compared, and the community structure and composition were also analyzed. Results from high-throughput sequencing of 16S rRNA showed that the diversity and species richness of biofilm bacterial communities on natural substrate (observed species of 1353~1945, Simpson index of 0.977~0.989 and Shannon–Wiener diversity index of 7.42~8.60) were much higher than those on plastic substrates (observed species of 900~1146, Simpson index of 0.914~0.975 and Shannon–Wiener diversity index of 5.47~6.99). The NMDS analyses were used to confirm the taxonomic significance between different samples, and Anosim (p = 0.001, R = 0.892) and Adonis (p = 0.001, R = 808, F = 11.19) demonstrated that this classification was statistically rigorous. Different dominant bacterial communities were found on plastic and natural substrates. Alphaproteobacterial, Betaproteobacteria and Synechococcophycideae dominated on the plastic substrate, while Gammaproteobacteria, Phycisphaerae and Planctomycetia played the main role on the natural substrates. The bacterial community structure of the two substrates also showed significant difference which is consistent with previous studies using other polymer types. Our results shed light on the fact that plastic debris can serve as a new habitat for biofilm colonization, unlike natural substrates, pathogens and plastic-degrading microorganisms selectively attached to plastic substrates, which affected the bacterial community structure and composition in aquatic environment. This study provided a new insight into understanding the potential impacts of plastics serving as a new habitat for microbial communities in freshwater environments. Future research should focus on the potential impacts of plastic-attached biofilms in various aquatic environments and the whole life cycle of plastics (i.e., from plastic fragments to microplastics) and also microbial flock characteristics using microbial plastics in the natural environment should also be addressed.

scholarly journals An Assessment of ERA5 Reanalysis for Antarctic Near-Surface Air Temperature

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 217
Author(s):  
Jiangping Zhu ◽  
Aihong Xie ◽  
Xiang Qin ◽  
Yetang Wang ◽  
Bing Xu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Antarctic Peninsula ◽  
Austral Summer ◽  
Correlation Coefficients ◽  
East Antarctica ◽  
West Antarctica ◽  
Austral Spring ◽  
Reanalysis Dataset ◽  
Near Surface ◽  
The Antarctic

The European Center for Medium-Range Weather Forecasts (ECMWF) released its latest reanalysis dataset named ERA5 in 2017. To assess the performance of ERA5 in Antarctica, we compare the near-surface temperature data from ERA5 and ERA-Interim with the measured data from 41 weather stations. ERA5 has a strong linear relationship with monthly observations, and the statistical significant correlation coefficients (p < 0.05) are higher than 0.95 at all stations selected. The performance of ERA5 shows regional differences, and the correlations are high in West Antarctica and low in East Antarctica. Compared with ERA5, ERA-Interim has a slightly higher linear relationship with observations in the Antarctic Peninsula. ERA5 agrees well with the temperature observations in austral spring, with significant correlation coefficients higher than 0.90 and bias lower than 0.70 °C. The temperature trend from ERA5 is consistent with that from observations, in which a cooling trend dominates East Antarctica and West Antarctica, while a warming trend exists in the Antarctic Peninsula except during austral summer. Generally, ERA5 can effectively represent the temperature changes in Antarctica and its three subregions. Although ERA5 has bias, ERA5 can play an important role as a powerful tool to explore the climate change in Antarctica with sparse in situ observations.

scholarly journals Effects of Ecological Restoration Using Non-Native Mangrove Kandelia obovata to Replace Invasive Spartina alterniflora on Intertidal Macrobenthos Community in Maoyan Island (Zhejiang, China)

2021 ◽  
Vol 9 (8) ◽  
pp. 788
Author(s):  
Qiuxuan Wang ◽  
Carlos Duarte ◽  
Li Song ◽  
George Christakos ◽  
Susana Agusti ◽  
...  
Keyword(s):  
Community Structure ◽  
Ecological Restoration ◽  
Spartina Alterniflora ◽  
Diversity Index ◽  
Invasion History ◽  
Kandelia Obovata ◽  
Wiener Diversity Index ◽  
Significant Difference ◽  
Spatial Differences ◽  
Average Biomass

Spartina alterniflora has extensively invaded the coastline of China, including in Maoyan Island of Zhejiang Province. Ecological restoration has been conducted using non-native mangrove Kandelia obovata to replace S. alterniflora in an attempt to restore the impacted intertidal zones. To illustrate the ecological effectiveness of the restoration projects, macrobenthos communities were studied among different habitats within the restored areas, including one non-restored S. alterniflora marsh (SA) and three differently-aged restored K. obovata stands planted in 2003, 2009, and 2011 respectively (KF14, KF8, and KF6). Besides, one unvegetated mudflat (MF) adjacent to the non-restored S. alterniflora marsh and one K. obovata forest transplanted in 2006 (RKF) at a previously barren mudflat without invasion history of S. alterniflora were set as reference sites. A total of 69 species of macrobenthos were collected from Maoyan Island, and the species richness was dominated by gastropoda (23 species), polychaeta (18 species), and malacostraca (16 species). There was no significant difference between the six sites in terms of the abundance of macrobenthos, with the average values of abundance peaking in KF6 (734.7 ind m−2) and being lowest in RKF (341.3 ind m−2). The six sites had significant differences in terms of the biomass of macrobenthos. The KF8 site contained the highest average biomass (168.3 g m−2), whereas the MF site had the lowest (54.3 g m−2). The Shannon-Wiener diversity index and Pielou’s evenness index of the macrobenthos did not exhibit significant differences among the six sites. However, the results of permutational multivariate analysis of variance (PERMANOVA) revealed significant spatial differences in the macrobenthos community structure between the sites. Since KF14 shared a similar macrobenthos community structure with RKF, while representing a strikingly different structure from SA, we infer that ecological restoration using K. obovata can restore the macrobenthos community to resemble to a normally planted K. obovata forest about 15 years after restoration.

Spatio-temporal variability of zoobenthic communities in a tectonic lagoon (Lake Vouliagmeni, Attika, Greece)

2008 ◽  
Vol 88 (5) ◽  
pp. 873-881 ◽  
Author(s):  
Chariton Chintiroglou ◽  
Chryssanthi Antoniadou ◽  
Panagiotis Damianidis
Keyword(s):  
Multivariate Analyses ◽  
Benthic Communities ◽  
Marine Species ◽  
Trophic Group ◽  
Spatial And Temporal Scales ◽  
Mediterranean Lagoons ◽  
Deposit Feeders ◽  
Spatio Temporal ◽  
Lagoon Lake ◽  
Hard Substrata

Lake Vouliagmeni (Attica, Greece) is a lagoon of great scientific interest due to its endemic fauna, widely used for recreational activities. Understanding the dynamics of this peculiar ecosystem is essential for its conservation. An ecological survey of the benthic communities was carried out, in both spatial and temporal scales. Material was collected with SCUBA diving, by taking off samples from the principal habitats of the lagoon, i.e. meadows, soft and hard substrata. The identification of the collected 61,975 living specimens revealed the presence of 12 floral and 20 faunal species. Multivariate analyses separated the sampling sites according to the four different habitats of the lagoon, whereas no temporal patterns came up. Micrograzers were the dominant trophic group, followed by deposit feeders regardless of the habitat studied. Lake Vouliagmeni is among the less diverse Mediterranean lagoons, mostly due to its isolation from the sea that hinders the entrance of marine species.

scholarly journals Effects of a 5-year trawling ban on the local benthic community in a wind farm in the Dutch coastal zone

2014 ◽  
Vol 72 (3) ◽  
pp. 962-972 ◽  
Author(s):  
Magda J. N. Bergman ◽  
Selma M. Ubels ◽  
Gerard C. A. Duineveld ◽  
Erik W. G. Meesters
Keyword(s):  
Coastal Zone ◽  
Benthic Community ◽  
Large Scale ◽  
Wind Farm ◽  
Diversity Index ◽  
Benthic Assemblages ◽  
The North ◽  
Wiener Diversity Index ◽  
Short Period ◽  
Reference Areas

Abstract As part of a large impact study in a wind farm (OWEZ) in the Dutch coastal zone, the effects of exclusion of bottom trawling on the benthic community were studied by comparison with nearby reference areas which were regularly fished. In addition to a standard boxcorer for common macrofauna, a Triple-D dredge was used to collect longer-lived, more sparsely distributed infauna and epifauna. Multivariate analysis did not reveal any difference between the assemblages in and outside OWEZ with respect to abundance, biomass, and production after a 5-year closure. The Shannon–Wiener diversity index pointed to a significantly higher diversity in OWEZ compared with some of the reference areas. A minority of the bivalve species assumed to be sensitive to trawling showed higher abundances (Spisula solida) or larger sizes (Tellina fabula, Ensis directus) in OWEZ than in some of the reference areas. In general, samples collected with the Triple-D showed more differences between areas than boxcore samples. No evidence was also found that the species composition in OWEZ relative to the reference areas had changed in the period between 1 (2007) and 5 (2011) years after closure. The change observed in all areas between 2007 and 2011 was mainly due to relatively small variations in species abundances. In conclusion, 5 years after the closure of OWEZ to fisheries, only subtle changes were measured in the local benthic community, i.e. a higher species diversity and an increased abundance and lengths of some bivalves. Depleted adult stocks, faunal patchiness, and a limited time for recovery (5 years) might explain that a significant recovery could not be found. The current study shows that designation of large-scale marine protected areas as planned for the North Sea will not automatically imply that restoration of benthic assemblages can be expected within a relatively short period of years.

scholarly journals Sampling a biodiversity hotspot: the orchid-bee fauna (Hymenoptera: Apidae) of Tarapoto, northeastern Peru, the richest and most diverse site of the Neotropics

2014 ◽  
Vol 74 (3 suppl 1) ◽  
pp. s33-s44 ◽  
Author(s):  
A Nemésio ◽  
C Rasmussen
Keyword(s):  
Diversity Index ◽  
Species Group ◽  
Biodiversity Hotspot ◽  
Single Site ◽  
Additional Species ◽  
Orchid Bees ◽  
Orchid Bee ◽  
Wiener Diversity Index ◽  
First Time

The orchid-bee fauna of the region of Tarapoto, northeastern Peru, was surveyed using seventeen different scents as baits to attract orchid-bee males. Six hundred and fifty-nine males belonging to 41 species were actively collected with insect nets during 120 hours in late July and early August, 2012. Euglossa dressleriMoure, 1968, Euglossa laurensiBembé, 2008, and Euglossa maculilabrisMoure, 1968, three species belonging to the Euglossa cybelia species-group, are here reported for Peru for the first time. Previous sporadic and unpublished samplings in the area recorded eleven additional species. With 53 species, the region of Tarapoto can be considered the richest single site in the Neotropics for orchid bees. Diversity, estimated with the Shannon-Wiener diversity index (H′ = 3.02), was also the highest ever recorded for orchid bees.

scholarly journals Distance Effects on Diversity and Abundance of the Flower Visitors of Ocimum kilimandscharicum in the Kakamega Forest Ecosystem

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Hellen K. Mandela ◽  
Mugatsia H. Tsingalia ◽  
Mary Gikungu ◽  
Wilbur M. Lwande
Keyword(s):  
Species Diversity ◽  
Diversity Index ◽  
Land Use Changes ◽  
Species Abundance ◽  
Diversity Indices ◽  
Forest Edge ◽  
Flower Visitors ◽  
Kakamega Forest ◽  
Species Invasions ◽  
Wiener Diversity Index

Pollination is an important ecosystem service in the maintenance of biodiversity and most importantly in food production. Pollination is on the decline due to habitat loss, exotic species invasions, pollution, overharvesting, and land use changes. This study analyzed the abundance and diversity of flower visitors’ of Ocimum kilimandscharicum in Kakamega forest with increasing distance from the forest edge. Data were collected through direct observation and sweep netting. Six study sites were identified along two transects each 2.5 km long and labeled A to F. Distance in metres from the forest edge to each site was A=221, B=72, C=83, D=198, E=113, and F=50. Sampling was done from 7:30 am to 4:00 pm, three days in a week for five months consecutively. Diversity indices of different flower visitors were calculated using the Shannon-Wiener diversity index. One-way analysis of variance was used to compare differences between sites and a two-sample t-test was used to identify mean significant differences in species diversity between the closest and the furthest sites. A total of 645 individuals belonging to 35 species were captured from 4 families. The highest diversity was at site F (H’= 2.38) which was closest to the forest edge and the lowest diversity was from site A (H’=1.44) which was furthest from the forest edge. Distance from the forest edge significantly influenced species diversity (F(3, 20)=14.67, p=0.024). Distance from the forest edge also significantly influenced species abundance between the furthest sites A, D, and E and the nearest sites F, B, and C to the forest edge (t=4.177; p=0.0312) and species richness (t=3.2893; p=0.0187). This study clearly demonstrates that Ocimum kilimandscharicum flower visitors play essential roles in pollination and their higher number of visits translates into higher numbers of seeds set. Many of these pollinators are associated with the forest and hence the need to conserve the Kakamega forest as a source pool for pollinators.

scholarly journals Next Generation Sequencing-Based Molecular Marker Development: A Case Study in Betula Alnoides

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2963 ◽  
Author(s):  
Jing Tan ◽  
Jun-Jie Guo ◽  
Ming-Yu Yin ◽  
Huan Wang ◽  
Wen-Pan Dong ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Molecular Marker ◽  
Ssr Markers ◽  
Southern China ◽  
Diversity Index ◽  
Next Generation ◽  
Wiener Diversity Index ◽  
Nucleotide Repeats ◽  
Betula Alnoides ◽  
Generation Sequencing

Betula alnoides is a fast-growing valuable indigenous tree species with multiple uses in the tropical and warm subtropical regions in South-East Asia and southern China. It has been proved to be tetraploid in most parts of its distribution in China. In the present study, next generation sequencing (NGS) technology was applied to develop numerous SSR markers for B. alnoides, and 64,376 contig sequences of 106,452 clean reads containing 164,357 candidate SSR loci were obtained. Among the derived SSR repeats, mono-nucleotide was the main type (77.05%), followed by di- (10.18%), tetra- (6.12%), tri- (3.56%), penta- (2.14%) and hexa-nucleotide (0.95%). The short nucleotide sequence repeats accounted for 90.79%. Among the 291 repeat motifs, AG/CT (46.33%) and AT/AT (44.15%) were the most common di-nucleotide repeats, while AAT/ATT (48.98%) was the most common tri-nucleotide repeats. A total of 2549 primer sets were designed from the identified putative SSR regions of which 900 were randomly selected for evaluation of amplification successfulness and detection of polymorphism if amplified successfully. Three hundred and ten polymorphic markers were obtained through testing with 24 individuals from B. alnoides natural forest in Jingxi County, Guangxi, China. The number of alleles (NA) of each marker ranged from 2 to 19 with a mean of 5.14. The observed (HO) and expected (HE) heterozygosities varied from 0.04 to 1.00 and 0.04 to 0.92 with their means being 0.64 and 0.57, respectively. Shannon-Wiener diversity index (I) ranged from 0.10 to 2.68 with a mean of 1.12. Cross-species transferability was further examined for 96 pairs of SSR primers randomly selected, and it was found that 48.96–84.38% of the primer pairs could successfully amplify each of six related Betula species. The obtained SSR markers can be used to study population genetics and molecular marker assisted breeding, particularly genome-wide association study of these species in the future.

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