Periodicum biologorum, Vol. 116 No. 3, 2014.
Original scientific paper
The relative importance of physical-chemical factors in the brackish shallow lake Vrana (Croatia) as determinant of crustacean zooplankton community
Danijela Peroš-Pucar
; Health Ecology Service, Public Health Institute Zadar, Kolovare 2, Zadar, Croatia
IvančIca Ternjej
; Department of Zoology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, HR-10000 Zagreb, Croatia
Abstract
Background and Purpose: Lake Vrana is shallow, Mediterranean,
karstic lake, where water salinity is as an important ecological factor, because the lake is directly connected with the Adriatic Sea. Studies concerning zooplankton communities in these ecosystems are very scarce. To understand this very specific and unique ecosystem, the physical and chemical parameters and the makrozooplankton community structure in Lake Vrana were studied.
Material and Methods: The investigation was conducetd monthly from
January till December 2004 at four stations with different ecological characteristics (primarily depth, salinity, hydrology, nutrients supply). Chlorophyll a concentration was analyzed fluorometrically according to Method 445.0. Physical and chemical parameters (temperature, transparency, chlorinity, salinity, biological oxygen demand - BOD, dissolved oxygen - DO, ortho-phosphate, total phosphorus, chlorophyll a) were measured according to APHA. Data on environmental variables and makrozooplankton community were examined using Redundancy Analysis (RDA).
Results: Among the 13 different species which are found in macrozooplankton community of Lake Vrana, the dominant species were Calanipeda aquedulcis Kritchagin (Copepoda), and Bosmina longirostris O.F. Műller, (Cladocera) which were present in all four stations during study period. The same occurring had Megacyclops gigas Claus, Alona sp., Alonella excisa Fischer, and Chydorus sphaericus O.F. Műller while other species appeared sporadically. The physical-chemical parameters showed temporal and spatial variations in Lake Vrana during study period resulting in different micro-habitat conditions on the studied sites. That is confirmed by the results of the RDA analysis that clearly shows the separation of stations due to the impact of studied indicators. According to multivariate analysis temperature, chlorophyll a and salinity have great influence on dynamics and structure of makrozooplankton in Lake Vrana.
Conclusions: Temperature, chlorophyll a and salinity are ecological
factors which define the development as well as dynamics and structure of
macrozooplankton community in the Vrana Lake.
Keywords
zooplankton temporal variation; brackish shallow lakes; multivariate analysis
Hrčak ID:
135130
URI
Publication date:
30.9.2014.
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