Mechanisms of eutrophication in freshwater ecosystems
Main researcher
: HABDIJA, IVAN (14981) Assistants
KRULIK, IVANČICA (24144)
PRIMC-HABDIJA, BISERKA (68485)
MESARIĆ, NIVES (89714)
RADANOVIĆ, INES (165165)
Type of research: basic Duration from: 01/01/91. to 12/31/95. Papers on project (total): 14
Papers on project quoted in Current Contents: 4
Institution name: Prirodoslovno-matematički fakultet, Prirodoslovni odjeli, Zagreb (119) Department/Institute: Department of Biology Address: Rooseveltov trg 6 City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (0)41-442-607
Summary: Investigations of the eutrophication mechanisms are aimed
at theanalysis of functional community organization of invertebrates inthe
karst fresh waters located in NW Dinarid area. Methodic isbased on the
analysis of biomass and population density ofparticular functional feeding
groups. In headwater streams andupper river course, input of coarse
particulate organic matter(CPOM) from the banks is the main factor of
eutrophication. Inaddition, periphyton is very important food source for
thebenthic community. In these benthic communities the shredderfauna,
represented by amphipods and shredder insect larvae, andscrapers
represented by different species of gastropods, are themost abundant. At
habitats in lower river area the collectorfauna, represented by oligochaets
and dipteran larvae,constitutes the most percentage of the total
macrobenthicbiomass. Composition of predators varies along the
rivercontinuum but their percentage ranges below the 20% of the total.
In the karst lakes protozoans, rotifers and crustaceansconstitute more than
90% of the total plankton biomass. It wasfound that in comparasion with
influence of abiotical factors,the most responsible factors for the spatial
and temporaldistribution of zooplankton are supply of available
food,competition and predatory pressure. In general it can beconcluded that
the eutrophication mechanisms in the karst freshwater communities depend
upon the imput of quality and quantityof available food.
Research goals: The basic idea is to analyze the mechanisms of
eutrophication in the aquatic communities of karst fresh water. As the
eutrophication process is increase of energy flow through the food chains,
the investigations are aimed at the analysis of functional community
organization and the transfer of fixed energy in the form of organic matter
along the physical river continuum described by Vannote et al. (1980). The
planned research is based on the fact that the functional community
organization is a reflection of the energy and food relationships in the
aquatic communities. Relative abundance of consumer functional groups
indicates the model of energy conversion and energy flux through the food
chains. The knowledge of faunistic and trophic community structure give a
feasibility to the reconstruction of food chains, and the standing crop
biomass of particular consumer functional groups shows on the concentration
of fixed energy in the particular segments of trophic pyramid. Separately
the aspect of contamination by the toxic matter will be investigated
because by the elimination of particular food chain links, the toxic
components result the energy disturbance in the fresh water community. It
is presumed that the results of these fundamental faunistic and biocenotic
investigations can be applied in the technological development of
exploiting of karst fresh water. Other information about the project.