Naslov
The influence of tufa deposition on periphyton development

Autori
Matoničkin Kepčija, Renata ; Primc, Biserka ; Miliša, Marko ; Sertić Perić, Mirela ; Radanović, Ines ; Habdija Ivan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Abstract Book / Meyer, EI - Münster : German Limnological Society, 2013, 249-249

Skup
SEFS8 Symposium for European Freshwater Sciences

Mjesto i datum
Münster, Njemačka, 01.07.2013. - 05.07.2013

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Plitvice Lakes; flow velocity; chlorophyll a; protozoa; micro-metazoa

Sažetak
Tufa, a secondary calcium-carbonate deposit in freshwaters, creates a unique habitat for periphyton. Although generating increased sedimentation stress, tufa enhances resistance to hydraulic stress by incrusting periphyton matrix. In this study we used artificial substrata (glass-slides) to test whether increased calcium-carbonate deposition inhibits or promotes development of periphytic community and to assess the influence of flow velocity on both tufa-deposition and periphyton development. Experiments were set on two tufa barriers within the Plitvice Lakes barrage lake system (Croatia). One barrier showed low (LTD), and the other high (HTD) tufa deposition rate. On each barrier, three different reotopes were chosen, representing slow (20 cm s-1), medium (50 cm s-1) and fast (90 cm s-1) flow velocity sites. Glass-slides were exposed in-situ for two weeks between July and November 2002. Average tufa deposits on the slides were about sixfold higher in summer months (July, August, September ; TH2O = 19.4 ± 1.7°C) than in autumn (October, November ; TH2O = 10.1 ± 1.9°C). Increased flow velocity decreased the amount of tufa on glass slides, contrary to some previous investigations. Possible reason for such trend is increased sedimentation of lake-generated tufa in the medium and slow flow velocity sites. Algal biomass in periphyton, measured as chlorophyll a, was almost two times higher on the HTD barrier (1.02 mg m-2 on average) compared to the LTD barrier (0.60 mg m-2 on average), suggesting that tufa deposition created more suitable habitat for colonizing algae. Lower numbers of protozoan and micro-metazoan taxa were recorded on the HTD barrier (76 taxa), compared to the LTD barrier (88 taxa), indicating tufa deposition as a diversity-reducing factor. Periphyton abundance between the LTD and HTD barriers did not significantly differ, but the HTD barrier exhibited a strong dominance of few taxa, primarily stalked suctorians (Ciliophora). Number of taxa decreased with increasing flow velocity. The same trend was observed for abundance, but on the LTD sites only. At the HTD barrier all three rheotopes displayed almost the same abundance. The latter pattern might be caused by the effect of periphyton incrustation that implies thicker periphyton matrix, resistant to sloughing. The observed protozoa and micro-metazoa community structure reflected the considerable influence of the seasonal tufa deposition patterns on the tufa-dwelling communities.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

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