Tamara Dulić

Cyanobacteria and cyanotoxins in fishponds and their effects on fish tissue

Cyanobacteria can produce toxic metabolites known as cyanotoxins. Common and frequently investigated cyanotoxins include microcystins (MCs), nodularin (NOD) and saxitoxins (STXs). During the summer of 2011 extensive cyanobacterial growth was found in several fishponds in Serbia. Sampling of the water and fish (common carp, Cyprinus carpio) was performed. Water samples from 13 fishponds were found to contain saxitoxin, microcystin, and/or nodularin. LC-MS/MS showed that MC-RR was present in samples of fish muscle tissue. Histopathological analyses of fish grown in fishponds with cyanotoxin production showed histopathological damage to liver, kidney, gills, intestines and muscle tissues. This study is among the first so far to report severe hyperplasia of intestinal epithelium and severe degeneration of muscle tissue of fish after cyanobacterial exposure. These findings emphasize the importance of cyanobacterial and cyanotoxin monitoring in fishponds in order to recognize cyanotoxins and their potential effects on fish used for human consumption and, further, on human health.

Cyanobacteria and Algae of Biological Soil Crusts

Filamentous cyanobacteria are the key organisms in biological soil crust formation in all biomes of the world. However, especially in temperate, arctic, and high alpine regions, as well as in few dry Savannah ecosystems, filamentous green algae may act in a similar role. Here, we give an overview on the role, diversity, and biogeography of cyanobacteria and eukaryotic algae in biocrusts from all climatic regions and continents of the Earth. We refer to the species level wherever this is possible. Currently, there have been 320 species of cyanobacteria and more than 350 species of eukaryotic algae described from biocrusts. Despite this high diversity, only a minority of the cyanobacterial and algal species found is responsible for the bulk of biocrust formation. Others likely are opportunistic, utilizing the habitat created by biocrusts in the harsh regions of the Earth where habitable space is rare. We also discuss methods for the sampling and identification of biocrust algae and cyanobacteria.

Cyanobacterial effects in Lake Ludoš, Serbia - Is preservation of a degraded aquatic ecosystem justified?

Cyanobacteria are present in many aquatic ecosystems in Serbia. Lake Ludoš, a wetland area of international significance and an important habitat for waterbirds, has become the subject of intense research interest because of practically continuous blooming of cyanobacteria. Analyses of water samples indicated a deterioration of ecological condition and water quality, and the presence of toxin-producing cyanobacteria (the most abundant Limnothrix redekei, Pseudanabaena limnetica, Planktothrix agardhii and Microcystis spp.). Furthermore, microcystins were detected in plants and animals from the lake: in macrophyte rhizomes (Phragmites communis, Typha latifolia and Nymphaea elegans), and in the muscle, intestines, kidneys, gonads and gills of fish (Carassius gibelio). Moreover, histopathological deleterious effects (liver, kidney, gills and intestines) and DNA damage (liver and gills) were observed in fish. A potential treatment for the reduction of cyanobacterial populations employing hydrogen peroxide was tested during this study. The treatment was not effective in laboratory tests although further in-lake trials are needed to make final conclusions about the applicability of the method. Based on our observations of the cyanobacterial populations and cyanotoxins in the water, as well as other aquatic organisms and, a survey of historical data on Lake Ludoš, it can be concluded that the lake is continuously in a poor ecological state. Conservation of the lake in order to protect the waterbirds (without urgent control of eutrophication) actually endangers them and the rest of the biota in this wetland habitat, and possibly other ecosystems. Thus, urgent measures for restoration are required, so that the preservation of this Ramsar site would be meaningful.

Corrigendum to “Cyanobacteria and cyanotoxins in fishponds and their effects on fish tissue” [Harmful Algae 55 (2016) 66–76]

Damjana Drobac *, Nada Tokodi , Jelena Lujić , Zoran Marinović , Gordana Subakov-Simić , Tamara Dulić , Tamara Važić , Sonja Nybom , Jussi Meriluoto , Geoffrey A. Codd , Zorica Svirčev a,d a Department of Biology and Ecology, Faculty of Science, University of Novi Sad, Trg Dositeja Obradovića 2, Novi Sad 21000, Serbia b Department of Aquaculture, Szent István University, Páter Károly u. 1, Gödöllő 2100, Hungary c Faculty of Biology, University of Belgrade, Studentski trg 16, Belgrade 11000, Serbia d Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Tykistökatu 6 A, Turku 20520, Finland e School of the Environment, Flinders University, Adelaide 5042, SA, Australia