Naslov
Distribution of Viruses and Dissolved DNA along a Coastal Trophic Gradient in the Northern Adriatic Sea

Autori
Weinbauer, G. Marcus ; Fuks, Dragica ; Peduzzi, Peter

Izvornik
Applied and environmental microbiology (0099-2240) 59 (1993), 12; 4074-4082

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
viruses ; dissolved DNA ; trophic gradient ; Northern Adriatic Sea

Sažetak
The distribution of viral and other microbial abundances as well as the concentration of dissolved DNA(D-DNA) along a trophic gradient in the northern Adriatic Sea were determined. Virus abundance, covering a range of 1.2x10E9 to 8.7x10E10/liter were on average 2.5-fold higher in eutrophic than in mesotrophic stations. A 2.5-fold enrichment was also measured for chlorophyll a concentrations, whereas the densities of bacteria and heterotrophic nanoflagellates were only approximately 1.5-fold higher. The frequency of bacteria containing mature phage increased linearly with bacterial abundance.Assuming that mature phage is only visible during the last 14 to 27% of the latent period, we estimated that between 3.5 and 7.3% of bacterial population was infected at mesotrophic stations versus between 7.0 and 19.5% at eutrophic stations, indicating that the bacterial mortality due to viral lysis might increase with the degree od eutrophication. The frequency of bacteria with mature phage and the burst size varied significantly with the bacterial morthotype ; rod-shape cells, the most abundant morphotype, showed low infection rates but a high burst size. Concentrations of D-DNA varied significantly with season but not with trophic conditions. The estimated percentage of viral DNA on total D-DNA concentrations averaged 17.1% (range, 0.7 to 88.3%). Some kind of interaction between heterotrophic nanoflagellates and viruses is proposed. We conclude (i) that the significance of viruses varies with changing trophic conditions and (ii) that viral activity may play a significant role in food web structure under changing trophic conditions.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Biologija

POVEZANOST RADA