Distribuição espacial e dinâmica temporal da alga epizoáriaBasicladia chelonum associada ao cágado Phrynops geoffroanus no rio Uberabinha, Minas Gerais

by Rosa Zanelli, Helise Regina

Abstract (Summary)
Studies were developed about a population of Basicladia chelonum epizoic algae overthe Phrynops geoffroanus turtle carapace captures in an urban area of Uberabinha River, cityof Uberlândia, MG (18°54?34,5"S e 48°18?20,4"W). The fieldwork was accomplished duringthe morning, in the middle and end of each season, from August 2004 to June 2005, totalizingeight samples. The area was distinguished about flora composition in the river?s margins,temperature and relative air humidity, luminosity intensity and some physical and chemicalwater parameters. Three hundred and twenty Phrynops geoffroanus individuals were captured(205 female, 115 males), each collect with 40 individuals. After the capture, the turtles weretransported to the Reptile Sector of Uberlândia?s Federal University, they were markedindividually, their sexes identified and sheltered in concrete tanks. After this procedure,morphometrical and corporeal mass data were taken, and the front and back limbs, head,neck, tail, ventral part of the carapace marginal shields and plastral of the turtle were observedabout the presence of algae. In the carapace, when present, the algae were plotted in acetatesheets and the area of covering was estimated through Autodesk?s AutoCaAD 2002 softwarehelp. Samples of algae were collected through superficial scratching of the carapace and fixedin formaldehyde at 4%. For the study of dynamics of Basicladia chelonum were analyzedcharacteristics considered relevant as: 1) presence of sporangium (>75% abundant, 25-50%frequent, <10%); 2) plant height (biggest fiber); and 3) length and diameter of cells (basal,medial and sporangium). After sampling of epizoic algae, the Phrynops geoffroanusindividuals were reintroduced in the same capture point. Were encountered correlationsbetween air temperature and water temperature, dissolved oxygen an pH and oxygen chemicaldemand, rain with concentration of iron, ammonium, total nitrogen, total phosphorus,electrical conductivity and pH, totals dissolves solids, obscureness and concentrations ofnitrate, nitrite, iron and ammonium. The study area, the Uberabinha River is under greathuman influences, probably due to the unloading of domiciliary and industrials waste, mainlyderiving of the Tabocas stream. In all the samples occurrences of epizoic algae were observedin different body parts of Phrynops geoofroanus individuals. The porcentage of algaecoverage was higher in September and lower in the months of March and June (F=2,28;p<0,05). The algae coverage also was different between sex. The males showed morepercentage of coverage than females (F=8,60; p<0,05). Occurred a high number of individualswith algae in the rear marginal scute and lower in the front scute and in the bridge marginalscute (F=35,27; p<0,05) were observed sporangium in the all the samples of analyzed algae.They were abundant in the algae collected in September (F=5,86; p<0,05) and in the frontmarginal shields (F=114,62; p<0,05), and rare in collections of August, October, March andJune (F=4,85; p<0,05) and in the costal scute, rear marginal scute and in the vertebral scute(F=54,13; p<0,05). The morphometrical characters of the algae evidenced the seasonalitydoes not interfered in the populational dynamics of Basciladia chelonum, although it hadvariated significantly during the study period. Probably, abrasion, turbulence, dissection andconcentration of nutrients in the river?s water could be interfering in the amount of algaecoverage, also in the growing and developing of these in the different carapace parts of turtle.
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:José Fernando Pinese; Maria do Carmo Calijuri; Vera Lucia de Campos Brites

School:Universidade Federal de Uberlândia

School Location:Brazil

Source Type:Master's Thesis

Keywords:Phrynops geoffroanus Basicladia chelonum epizoic algae Algae coverage


Date of Publication:02/17/2006

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