Composition of the Phytoplankton in the reservoir Los Laureles, Francisco Morazán, Honduras

Abstract

The Laureles reservoir is an artificial ecosystem created for drinking water. The composition (abundance and diversity) of phytoplankton along with the physical parameters (temperature, conductivity, turbidity and Secchi disk), chemical (pH, dissolved oxygen) and biological (chlorophyll a) all during March-August 2014 was studied. Samples in three sampling points comprising curtain, middle and tail with 100 mL were obtained using trawl subsurface level 20 to 30 cm deep for two minutes to qualitative analysis and Van Dorn bottle for Secchi depth quantitative analysis.

Of the 21 taxa identified 7 belong to the cyanobacteria, diatoms and 5 to 9 at Chlorophycea. During the sampling time, the cyanobacteria were found in 67%, diatoms by 26% and 7% Chlorophyceae, it clinógrados profiles with oxygen and pH, high turbidity in the hypolimnion, persistent low Secchi transparency in all samples, and trophic state index data of a TSI 2011 for Secchi disk 58, 80 to 68 for total phosphorus and chlorophyll a, TSI values> 54 are to eutrophic lakes. All these factors indicate characteristics of eutrophic water bodies. However, for results with a higher degree of reliability, it is recommended that the physical, chemical, biological and productivity samplings at least every two weeks during the dry and rainy seasons, increasing the sampling when suspected algal blooms, as these relationships are more accurate when studies are performed yearly cycles, to identify patterns of variation and trends to help prevent and correct this problem.

Revista Portal de la Ciencia, No.11, diciembre 2016, p.90-104