Do toxic cyanobacteria blooms pose a threat to the Baltic ecosystem?

Abstract

Cyanobacteria, otherwise known as blue-green algae, are oxygenic, photosynthetic prokaryotes. They occur naturally in many fresh, marine and brackish waters worldwide and play an important role in global carbon and nitrogen cycles. In their long history, cyanobacteria have developed structures and mechanisms that enable them to survive and proliferate under different environmental conditions. In the Baltic Sea, the mass development of cyanobacteria is compounded by a high level of eutrophication. The dominant species in the Baltic, the filamentous Aphanizomenon flos-aquae and Nodularia spumigena, can fix dissolved atmospheric N 2 , as a result of which they can outcompete other phytoplankton organisms. Heterocystous, filamentous cyanobacteria also make a significant contribution The complete text of the paper is available at http://www.iopan.gda.pl/oceanologia/ 294 H. Mazur-Marzec, M. Pliński to the internal nutrient loading in the Baltic. The blooms of N. spumigena are of particular concern, as this cyanobacterium produces nodularin (NOD), a hepatotoxic peptide. The concentration of the toxin in the sea is regulated mainly by dilution with uncontaminated water, photolysis, sorption to sediments and microbial degradation. The transfer of the toxin in the Baltic trophic chain through zooplankton, mussels, fish and birds has been reported, but biodilution rather than bioconcentration has been observed. Cyanobacterial blooms are thought to pose a serious threat to the ecosystem. Their harmful effects are related to the occurrence of a high biomass, oxygen depletion, a reduction in biodiversity, and the production of toxic metabolites.

Newly isolated Nodularia phage influences cyanobacterial community dynamics

“…Nodularia spumigena has been identified as one of the most important species causing harmful cyanobacterial blooms in the Baltic Sea (Sivonen et al, 1989;Mazur-Marzec and Pli nski, 2009). Even though several studies recognize the importance of phages in bacterial community dynamics, the only report on Nodularia-specific phages isolated from the Baltic Sea dates a decade back, when Jenkins and Hayes (2006) isolated 17 myo-and siphophages infecting N. spumigena.…”

Growth, toxicity and oxidative stress of a cultured cyanobacterium (Dolichospermum sp.) under different CO2/pH and temperature conditions

“…and Nodularia spumigena. N. spumigena is a well-known toxin producer that affects aquatic and terrestrial organisms, and may pose a health hazard for humans (Sellner 1997;Mazur-Marzec & Pliń ski 2009). Aphanizomenon sp.…”

Cyanobacterial Toxin Degrading Bacteria: Who Are They?

“…This could be partially due to the notion that cyanotoxins are relatively recalcitrant to chemical degradation [5] and were thought as nonlabile for biodegradation as well. However, advances in molecular microbial ecology have elucidated that strains of the bacterial genera Sphingomonas, Sphingosinicella, Arthrobacter, Brevibacterium, Rhodococcus, and Burkholderia can degrade microcystins (MC) and nodularins in time scales from hours to days [6, 7]. Moreover, we are now aware of eukaryotic mechanisms of cyanotoxin elimination in animal tissues [8–10].…”