scholarly journals Benthic Macrofauna Associated with Submerged Bottoms of a Tectonic Estuary in Tropical Eastern Pacific

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Carlos E. Guevara-Fletcher ◽  
Jaime R. Cantera Kintz ◽  
Luz M. Mejía-Ladino ◽  
Fabián A. Cortés

The composition and distribution of the main associations of submerged macrobenthos ofBahía Málaga(Colombian pacific coast), were studied in relation to the distribution of hard and soft substrates and some abiotic factors. Eight localities were sampled during six months: three in the external border of the estuary and five in the inner part. In total, 728 organisms were registered, belonging to 207 species, 132 genera, 86 families, and 14 orders of six invertebrate groups (Porifera, Cnidaria, Polychaeta, Mollusca, Crustacea, and Echinodermata). The submerged bottoms presented soft and hard substrates, with rocks and thick sand in five sites, soft bottoms with fine sand in one, and soft bottoms with slime and clay in two. The temperature and salinity values were higher in the external localities, while dissolved oxygen and pH were higher in the internal localities. The localities with hard substrates presented the highest richness of species while the soft substrates, were characterized by a paucity of species and individuals. The similarity classification analyses showed two groups: one characterized by having 61 species in common and high richness with 113 exclusive species. The other group with low diversity and richness values, 37 species in common and 23 exclusive species.

Author(s):  
Celia Olabarria

This study quantifies the prevalence, abundance, and spatial distribution of epibiotic molluscs on six common neogastropod species in sandy bottoms, Hexaplex nigritus, Chicoreus regius, C. erythrostomus, C. brassica, Vasum caestus and Pleuropoca princeps. A total of 1478 epibiont specimens belonging to 74 mollusc species were examined. The most of epibiotic species were typical of hard-bottoms, but a few species were typical of soft-bottoms. The results indicate H. nigritus is significantly more fouled than the other five species. This can be due to a greater availability of small hollows and a strongly ornamented shell in this species. The spatial distribution of epibionts on the neogastropod shells varied significantly among the different areas into which the shell was subdivided for this study. Fifteen sedentary epibiotic species dominated on all host shells. The costs and benefits of epibiosis are reviewed and the epibiont/host relationship appears to be principally beneficial to epibionts, without a clear benefit for hosts.


2012 ◽  
Vol 60 (2) ◽  
pp. 135-148 ◽  
Author(s):  
Jenyffer Vierheller Vieira ◽  
Carlos Alberto Borzone ◽  
Luciano Lorenzi ◽  
Fabiano Grecco de Carvalho

Pollution, exploitation of resources, erosion and recreational activities produce the most common impacts that somehow alter the natural balance of beach ecosystems. The aim of this study was to compare the richness and abundance of the benthic macrofauna of two sectors, one non-urbanized and the other urbanized, on each of two morphodynamically different beaches. Sectors of each beach were analyzed taking into account morphodynamic, anthropogenic (recreational activities) and ecological aspects. Morphodynamically, one of the beaches presented sediment formed of fine sand with a gentle slope and morphodynamism with dissipative characteristics. The other was of sediment formed of medium sand with a steep profile and of intermediate to reflective morphodynamic characteristics. On both beaches during the summer, the urbanized sector was frequented by a greater number of users than the non-urbanized sector. On the beach with dissipative morphodynamism, negative relationships were observed between user abundance and the species Bledius bonariensis, Donax hanleyanus, Thoracophelia furcifera, Excirolana armata, Phoxocephalopsis sp. and Tholozodium rhombofrontalis. On the beach with intermediate to reflective morphodynamics, low abundances of Atlantorchestoidea brasiliensis and Excirolana braziliensis were recorded in the urbanized sector. Thus the results of this study suggest the use of certain species as indicators of human impacts on beach ecosystems.


2015 ◽  
Vol 41 (1) ◽  
pp. 13-19
Author(s):  
Kaniz Fatema ◽  
Wan Maznah Wan Omar ◽  
Mansor Mat Isa

Water quality in three different stations of Merbok estuary was investigated limnologically from October, 2010 to September, 2011. Water temperature, transparency and total suspended solids (TSS) varied from 27.45 - 30.450C, 7.5 - 120 cm and 10 -140 mg/l, respectively. Dissolved Oxygen (DO) concentration ranged from 1.22-10.8 mg/l, while salinity ranged from 3.5-35.00 ppt. pH and conductivity ranged from 6.35 - 8.25 and 40 - 380 ?S/cm, respectively. Kruskal Wallis H test shows that water quality parameters were significantly different among the sampling months and stations (p<0.05). This study revealed that DO, salinity, conductivity and transparency were higher in wet season and TSS was higher in dry season. On the other hand, temperature and pH did not follow any seasonal trends.Bangladesh J. Zool. 41(1): 13-19, 2013


Zootaxa ◽  
2018 ◽  
Vol 4429 (1) ◽  
pp. 157
Author(s):  
LUCIANA MARTINS ◽  
MARCOS TAVARES

Paulayellus gustavi, a new sclerodactylid genus and species, is described from the Pacific coast of Panama. The new genus and species is assigned to the subfamily Sclerothyoninae based on a suite of characters, which include the radial and interradial plates of the calcareous ring united at the base only. Paulayellus gen. nov. differs from the other Sclerothyoninae genera in having posterior processesof radial plates undivided. Additionally, differs from Sclerothyone, Thandarum and Neopentamera in having knobbed buttons, plates and cups in the body wall (whereas the body wall is furnished only with tables and plates in Sclerothyone, Temparena and Thandarum, and only with knobbed buttons and plates in Neopentamera). The new genus is, so far, monotypic. The also monotypic genus Neopentamera proved to have the radial and the interradial plates of the calcareous ring united at the base only, as typically found in the Sclerothyoninae, and is therefore transferred to that subfamily. The discovery of a new genus in the Sclerothyoninae and the transfer of Neopentamera required the amendation of the diagnosis for the subfamily. A key to the Sclerothyoninae is given. 


Author(s):  
Pierre Gnohossou ◽  
Christophe Piscart

During a recent investigation of the benthic macrofauna from coastal lagoons of southern Benin (Ahémé, Nokoué and Porto-Novo lagoons), a new species of the amphipod genus Quadrivisio Stebbing, 1907, Q. laleyei sp. nov. was collected by means of different quantitative and non-quantitative methods (plastic baskets, wooden artificial substrates, uprooted plants and Surber net) in their intertidal macrophyte zone. The new species can be easily distinguished from most of the other species of the genus by the setation of the mandibular palp and telson and a reduced number of articles (4–6) on the accessory flagellum of the first antenna. The new species closely resembles to Q. lutzi (Shoemaker, 1933) but clearly differ by a reduced armature of the urosomites 1 and 2 and by the geographical distribution (Q. lutzi being known only in Central and South America). Ecological data and an updated key to a species in the genus Quadrivisio are provided. 


1979 ◽  
Vol 51 (1) ◽  
pp. 158-162 ◽  
Author(s):  
Antti Jaakkola ◽  
Johan Korkman ◽  
Tuomo Juvankoski

The aim of the study was to find out to what extent the cadmium contained in fertilizer influences the cadmium content of vegetables. For this purpose, highly cadmium-bearing batches of fertilizer were prepared from selected quantities of raw material with an exceptionally high cadmium content. To one such batch of fertilizer, an extra amount of cadmium was added at the mixing stage. In a two-year field experiment carried out in soil consisting of clayey fine sand and begun in 1977, 1000 kg/ha of NPK fertilizer with a cadmium content of either 57 or 81 mg/kg brought about a clear increase in the cadmium content of radish tops. The cadmium content of radish roots, spinach and lettuce appeared likewise to rise, but the differences registered were not, owing to the unevenness of the field, significant. The cadmium content of the dry matter of rye grass was lower than that of the other experimental plants, and it appeared to rise less with an increase in the cadmium content of the fertilizer. Owing to the wide range of variation, the cadmium uptake of the experimental plants could not be determined reliably, The spinach, however, appeared to have taken up the largest amount of cadmium, and the rye grass the least amount. The increase in the cadmium content of the spinach harvested in 1978 corresponded to 1.5‰ of the cadmium introduced into the ground during the two-year period through application of the fertilizer with the highest content of the metallic element.


2014 ◽  
Vol 919-921 ◽  
pp. 1104-1109
Author(s):  
Chen Rui Pang ◽  
Xin Wen

Waste soil progressing in shield tunnel construction should occupy large space, on the other hand, do harm to city environment. If the waste sand in silt and fine sand layer can be used as sand source of synchronous grouting, it will bring benefits for the enterprise and society. In indoor experiment, we select waste sand in different layers, sieved as sand source, then use the waste sand to produce slurry and compare their strength with the construction slurry’s. The study found, sieved waste sand in silt and fine sand layer can be used as sand source for making synchronous grouting slurry.


2018 ◽  
Vol 87 (1) ◽  
pp. 150-172
Author(s):  
Katherine G. Morrissey

The following was the author’s presidential address at the annual meeting of the Pacific Coast Branch, American Historical Association, in Northridge, California, on August 4, 2017. The twentieth-century visual history of the U.S.-Mexico borderlands, la frontera, offers a rich set of representations of the shared border environments. Photographs, distributed in the United States and in Mexico, allow us to trace emerging ideas about the border region and the politicized borderline. This essay explores two border visualization projects—one centered on the Mexican Revolution and the visual vocabulary of the Mexican nation and the other on the repeat photography of plant ecologists—that illustrate the simultaneous instability and power of borders.


2011 ◽  
Vol 59 (1) ◽  
pp. 27-42 ◽  
Author(s):  
Ana Maria S Pires-Vanin ◽  
Pablo Muniz ◽  
Fabio Cabrera De Léo

Structure of intertidal and subtidal benthic macrofauna in the northeastern region of Todos os Santos Bay (TSB), northeast Brazil, was investigated during a period of two years. Relationships with environmental parameters were studied through uni-and multivariate statistical analyses, and the main distributional patterns shown to be especially related to sediment type and content of organic fractions (Carbon, Nitrogen, Phosphorus), on both temporal and spatial scales. Polychaete annelids accounted for more than 70% of the total fauna and showed low densities, species richness and diversity, except for the area situated on the reef banks. These banks constitute a peculiar environment in relation to the rest of the region by having coarse sediments poor in organic matter and rich in biodetritic carbonates besides an abundant and diverse fauna. The intertidal region and the shallower area nearer to the oil refinery RLAM, with sediments composed mainly of fine sand, seem to constitute an unstable system with few highly dominant species, such as Armandia polyophthalma and Laeonereis acuta. In the other regions of TSB, where muddy bottoms predominated, densities and diversity were low, especially in the stations near the refinery. Here the lowest values of the biological indicators occurred together with the highest organic compound content. In addition, the nearest sites (stations 4 and 7) were sometimes azoic. The adjacent Caboto, considered as a control area at first, presented low density but intermediate values of species diversity, which indicates a less disturbed environment in relation to the pelitic infralittoral in front of the refinery. The results of the ordination analyses evidenced five homogeneous groups of stations (intertidal; reef banks; pelitic infralittoral; mixed sediments; Caboto) with different specific patterns, a fact which seems to be mainly related to granulometry and chemical sediment characteristics.


Author(s):  
Vinícius Londe ◽  
Jaqueline Alves Pereira ◽  
Hildeberto Caldas de Sousa

Abstract Although important, phenological studies comparing congeneric species or the same species growing in different habitats are still scarce for the tropics. Herein, we integrate phylogeny, ecology and biometeorology to verify whether the phenophases of congeneric species Myrcia laruotteana and Myrcia amazonica or Clethra scabra differ when their populations inhabit wetland and drained habitats and to determine what abiotic factors affect the vegetative and reproductive phenophases of these species in distinct habitat patches. We collected data on phenological events of 80 trees for 1 year in Itacolomi State Park, Brazil, and related them to abiotic local factors. Contrary to our expectation, the phenophases of the congeneric species did not differ between habitats, but the reproductive phenophases of C. scabra did and was greater in drained soil. Phenophases of C. scabra were affected by the depth of the water table and maximum temperature in the wetland soil. Insolation, precipitation, maximum temperature and relative humidity influenced Myrcia and Clethra in the drained soil. The differences between C. scabra populations suggest that this species is phenotypically plastic and can present distinct phenophases depending on the habitat it inhabits. On the other hand, the congeneric Myrcia species may have similar phenophases in distinct habitats because of their shared similarities during their evolution. This study provides a better understanding of the ecology of these species and their adaptations to different abiotic conditions. Data of this nature are important in a changing world and can inform strategies for adaptive management.


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