Diel and seasonal periodicity in the drift of species Gammarus fossarum (Amphipoda: Gammaridae) in the Stiper stream, Kalnik

Žilić, Marija (2009) Diel and seasonal periodicity in the drift of species Gammarus fossarum (Amphipoda: Gammaridae) in the Stiper stream, Kalnik. Diploma thesis, Faculty of Science > Department of Biology.

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Abstract

In this study diel and seasonal changes of Gammarus fossarum drift were studied in a small second-order branch of the Stiper stream, tributary of the Bednja River, in the southeastern part of the Kalnik Mountain, from May 2001 to June 2002. Dift samples were collected once a month, every four hours with aluminium drift sampler (200 μm mesh size) and results were presented as drift rate (no. ind. 4h-1). Physico-chemical parameters measured twice a month were: air and water temperature, dissolved oxygen, oxygen saturation, conductivity, alkalinity, pH, width and depth of the stream, and night length also noticed. The purpose of this study was to determine effects of abiotic factors on diel and seasonal changes of amphipod Gammarus fossarum drift. Drift rates were greater during the night than during the day in all months. Night length affected number of drift peaks. During the long winter and autumn nights two drift peaks were observed, and during short summer and spring nights only one peak occured, with exceptions in January and February when only one peak was observed. The exuvial drift rates were much higher during the day in spring and summer months, but during winter months they were higher during the night. Much higher drift rates of gammarids and their exuvia were recorded during summer, while during winter months drift was much lower. Drift rate reached secondary peak in February. Highly positive relationship between drift and water temperature was observed (r=0.50). Among other factors only width and depth (indirect measures of flow) were in slight negative correlation with drift, showing that flow was negatively affected drift. Exuvial drift was in slight positive correlation with temperature (r=0.28) and conductivity was the most strongly positively correlated with drift (r=0.50), while other abiotic factors had slight or no effect on exuvial drift.

Item Type: Thesis (Diploma thesis)
Keywords: Gammarus fossarum, drift rate, diel periodicity, seasonal changes, exuvia
Supervisor: Gottstein, Sanja
Co-supervisor: Žganec, Krešimir
Date: 2009
Number of Pages: 42
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Silvana Šehić
Date Deposited: 10 Sep 2014 11:26
Last Modified: 10 Sep 2014 11:26
URI: http://digre.pmf.unizg.hr/id/eprint/2698

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