Bloom and eutrophication of Hydrodictyon reticulatum (Chlorophyceae) at Civil and Kacali Stream, Ordu, Turkey

Abstract

Civil and Kacali streams are one of the most important streams of Ordu city. However, there were too much pollution in down parts of these streams due to environmental vastes, coming from sewages and agricultural activities. When water flow decreased in dry seasons, eutrophication was observed following water blooms in these streams. Extreme eutrophications occurred in Civil and Kacali streams at the end of spring and early summer in 2009. Because of excessive algal blooms, dense green masses covered a large portion of the stream surfaces in the study term. In the examination of both the stream, Hydrodictyon reticulatum (Linnaeus) Bory de Saint-Vincent (water net) from the filamentous green algae let to excessive water blooms. This alga is a species that reduces oxygen level and disrupts the appearance in this types of watfers where are stagnant and shallow. Dissolved oxygen was determined as 4.76 mg/L in Civil Stream and 7.23 mg/L Kacali Stream in blooming time. In during eutrophication, sampling was made from the two streams and some physico-chemical and biological properties were examined. Results of analysis were compared with standards of the Turkish Water Pollution Control Regulation (WPCR). Phosphorous which is the important nutrient and causes water bloom was found at high ratio in the stream waters. In terms of these parameters, the streams have water quality at fourth category. It was determined that Civil Stream was much more polluted than Kacali Stream.