SASTAV FITOPLANKTONA NA UZGAJALIŠTU RIBA I ŠKOLJKAŠA U UVALI KALDONTA (OTOK CRES)

Autor: Marija Tomec
Jazyk: chorvatština
Rok vydání: 2004
Předmět:
Zdroj: Croatian Journal of Fisheries : Ribarstvo
Volume 62
Issue 4
Croatian Journal of Fisheries, Vol 62, Iss 4, Pp 127-142 (2004)
ISSN: 1848-0586
1330-061X
Popis: Uvala Kaldonta nalazi se na jugozapadnoj obali otoka Cresa u Lošinjskom kanalu na području bez većeg utjecaja opće morske struje. U uvali su postavljena 44 plutajuća kaveza veličine 5x10 metara u kojima se uspješno proizvodi oko 70 tona morske ribe: komarča (Sparus aurata), lubin (Dicentrarchus labrax), pic (Diplodus puntazzo) i zubatac (Dentex dentex). Uz neke fizikalnokemijske pokazatelje (temperatura mora, prozirnost, salinitet), posebna je pozornost posvećena kvalitativnom sastavu mrežnog fitoplanktona, a istraživanje je provedeno tijekom godine 2003. (svibanj, rujan, prosinac) i 2004. (veljača) na pet lokaliteta u uvali Kaldonta (Slika 1), na dubinama od 0,5 m, 5 m, 10 m, 20 m i 1 metar iznad dna. Prema fizikalnim i kemijskim pokazateljima, temperatura mora bila je pod utjecajem temperature okoliša, a prozirnost upućuje na oligotrofiju istraživanog akvatorija tijekom istraživanog razdoblja. U kvalitativnom sastavu mrežnog fitoplanktona, utvrđena je 161 vrsta mikrofita, a pripadale su sistematskim odjeljcima Cyanobacteria, Chrysophyta i Dinophyta (Tablica 1). Najbrojnija skupina alga bile su dijatomeje ili Bacillariophyceae (98 vrsta ili 61%) s relativnim učestalostima vrsta od 1 do 7. Taksonomski sastav dijatomeja upućuje na dominantnu zajednicu Chaetoceros –Rhizosolenia (Proboscia), a najviše dijatomejskih vrsta nađeno je u kasnojesenskom razdoblju (početak prosinca). Subdominantan brojnošću vrsta bio je odjel Dinophyta (55 vrsta ili 34,1%), s dominantnim vrstama rodova Ceratium i Protoperidinium. Tijekom istraživanja predstavnici spomenutog odjela nisu pokazivali veliku raznolikost vrsta u vodenom stupcu. Relativna učestalost vrsta bila je uglavnom 1, rjeđe 2 i 3, a najviše je dinofita nađeno u rujnu. Od Cyanobacteria (5 vrsta ili 3,1%) utvrđene su samo nitaste alge s relativnom frekvencijom od 1 do 3. Kvalitativni sastav mrežnog fitoplanktona upućuje na sličan sastav vrsta u vodenom stupcu na svim istraživanim lokalitetima. Prema dobivenim karakteristikama mrežnog fitoplanktona, istraživani lokaliteti čine stabilan ekosustav.
The Kaldonta Bay is situated at the south–western coast of the Cres island in the Lošinj channel, rather protected from larger influence of general sea water current. In the Bay there are installed 44 floating cages of 5 by 10 m dimensions. The cages are used for the culture of about 70 tons of sea water fish: gilthead sea bream (Sparus aurata), sea bass (Dicentrarchus labrax), sharp–snouted sparus (Diplodus puntazzo) and dentex (Dentex dentex). Besides some physico–chemical parameters (sea water temperature, transparence and salinity), special attention has been paid to the qualitative composition of net phytoplankton. Investigations were performed in the period of May, September and December 2003 and February 2004 at five locations in the Kaldonta Bay (Figure 1) at the depths of 0.5 m, 5 m, 10 m and 1 m from the bottom. According to the physico–chemical parameters, sea water temperature was influenced by the temperature of the environment, and the transparence suggested to the oligotrophic situation in the investigated aquatorium. Qualitative composition of net phytoplankton comprised 161 microphytic species belonging to the systematic compartments of Cyanobacteria, Chrysophyta and Dinophyta (Table 1). The most numerous algal group were diatoms or Bacillarophyceae (98 species or 61%), with relative frequencies of species from 1 to 7. Taxonomic composition of diatoms showed Chaetoceros–Rhizosolenia (Proboscia) to be the dominant community. Diatom species was the most abundant in late autumn period (beginning of December). The second most important comparatment were Dinophyta (55 species or 34.1%), with the dominant genera Ceratium and Protoperidinium. During the investigation, the representatives of Dinophyta did not show large variety of species in the water column. Relative frequency of the species was 1, rarely 2 and 3. Dinophyts were the most abundant in September. From Cyanobacteria (5 species or 3.1%) only filamentous algae were determined, with relative frequency from 1 to 3. Qualitative composition of net phytoplankton suggests the similarity of species composition in the water column at all the investigated locations. From all characteristics of net phytoplankton that were obtained conclusion can be made that all the investigated locations represent stable ecosystems.
Databáze: OpenAIRE
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