SOME OBSERVATIONS OF BUCCAL DEFORMITIES IN CHIRONOMID LARVAE (DIPTERA: CHIRONOMIDAE) FROM THE CIÉNAGA GRANDE DE SANTA MARTA, COLOMBIA
<div>The mouthpart deformities of chironomid larvae are considered as indicators of</div><div>environmental stress caused by water pollution such as heavy metals, pesticides, but</div><div>as well by organic contamination. In the present study larvae from the side chann...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Universidad Nacional de Colombia
2004-06-01
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| Series: | Caldasia |
| Online Access: | http://www.revistas.unal.edu.co/index.php/cal/article/view/39366 |
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| Summary: | <div>The mouthpart deformities of chironomid larvae are considered as indicators of</div><div>environmental stress caused by water pollution such as heavy metals, pesticides, but</div><div>as well by organic contamination. In the present study larvae from the side channels</div><div>of the Ciénaga Grande de Santa Marta were investigated. The chironomid community</div><div>of the channels are dominated by species of the genera Goeldichironomus and</div><div>Chironomus. All together 21 taxa were determined. The average proportion of mouthpart</div><div>deformities in all chironomid larvae was 21 percent. Incidents of mechanical abrasion</div><div>reached up to 59 percent. The highest frequency of abnormalities occurred in</div><div>Goeldichironomus carus in which more than 90 percent of all specimens were affected.</div><div>These numbers found here are fairly above average frequencies observed even at</div><div>polluted sites. Under natural conditions deformity frequencies are expected not to</div><div>exceed 8 percent. On the one hand, distinct concentrations of heavy metals originating</div><div>from Río Magdalena can be detected in the sediments of the channels. On the other,</div><div>these concentrations do not reach the levels which are described as triggers of high</div><div>deformation rates like those found here. The most plausible explanation of these</div><div>contradictory findings assumes a non-detected synergism of several environmental</div><div>stressors. Possibly, the physical structure of the deposited sediments and a pronounced</div><div>nocturnal oxygen depletion owing to organic pollution contribute an important part to</div><div>the crucial processes on a small spatial scale. However, as far as no further investigative</div><div>efforts will be done the reason for this phenomenon of high deformity frequencies will</div><div>remain conspicuous but speculative to a large extent.</div> |
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| ISSN: | 0366-5232 |