Harmful algae and toxic cyanobacteria

Introduction

Hazardous algae, in particular toxic cyanobacteria, pose a serious problem for modern ecology. Ecological changes that have been observed in different types of water ecosystems on land and at sea are of a multi-aspectual character. For several years now a permanent increase in the fertility of surface waters has been registered. This has serious biocenotic consequences. Species differentiation is decreased. Blooms of algae or cyanobacteria are increasingly more frequent with a clearly established domination of one species. The greenhouse effect, reflected by the increased temperature of natural waters, contributes to the intensification of cyanobacteria blooms. Together they pose the risk of internal ecosystem imbalance, or in other words, a disturbance of its homeostasis.
The phenomenon of homeostasis as the balanced status of the system plays an increasingly important role in the discussion about self-regulation mechanisms in ecology. The stability of homeostasis is conditional upon the mechanisms of the system coherence. Any system is exposed to external influences. When the threshold of internal coherence is crossed disturbances are introduced into the system. The degree of homeostasis disturbance, or in other words, the scope of interference into its stability depends on the intensity of external factors and on the degree of internal coherence of the system itself. For the past few decades, more and more often homeostasis disturbances have been observed in water reservoirs that were advanced enough to create a potentially new ecosystem structure dominated by few species showing a tremendously intensive growth usually connected with the appearance of blooms. Many such blooms are caused by toxic genera dangerous to human and animal health, resulting in economic loses through reduction of profits from aquacultures, tourism and recreation.
The issues connected with algae and cyanobacteria blooms are widely known and frequently discussed. Due to their importance, however, they become the subject of the conference organised by the Department of Sea Biology and Ecology at University of Gdansk under the auspices of the Centre of Excellence for Baltic Development, Education and Research, BALTDER, from 18 to 22 May 2005. The conference encompassed two sessions. The first one, entitled “Hazardous algae – a problem for modern ecology” took place in Gdansk on 18 and 19 May; the other session entitled “Toxic cyanobacteria – a problem of the future” was staged in Krynica Morska over the Vistula Lagoon on 19-22 May. The Krynica Morska session was at the same time the XXIV Symposium of the Phycological Section of the Polish Botanical Society. As well as members of the society, many guests form abroad participated in the symposium who were specialists in the field of hazardous algae and toxic cyanobacteria blooms, including Geoffrey A. Codd from the United Kingdom, Rosmarie Rippka from France, Jiři Komárek from the Czech Republic, Kaarina Sivonen and Jussi Meriluoto from Finland, Edna Granéli from Sweden, Maija Balode from Latvia, Ingrid Chorus, Stephan Pflugmacher and Horst Lange-Bertalot from Germany, Harald G. Marshall from the United States, František Hindák from Slovakia.
Discussions during the conference covered many cognitive issues related especially to the taxonomy and ecology of cyanobacteria. Methodological problems also attracted much interest, both in relation to field research and to the modern biochemical and genetic methods utilised in laboratories. A round-table discussion was conducted into how to monitor cyanobacteria blooms. The biology and ecology related problems were also discussed for various algae taxonomic groups, including diatoms, chlorophytes, euglenophytes, dinophytes, and charophytes. Detailed programs of the sessions have been included in the conference materials. This volume presents selected articles delivered and presented by their authors during the conference.