Research area: distribution and establishment of alien cyanobacteria in the temperate zone, composition of cyanobacteria in eutrophic lakes (microscopy, analysis of environmental variables). Interspecific competition in freshwater communities. Analysis of secondary metabolite production by biochemical and chromatographic methods (ELISA, HPLC). Phylogenetics, analysis of cyanotoxins and functional genes (PCR, genome sequencing). Cultural collections.
Annotation of the dissertation
The aim – the study of alien and native, potentially toxic, bloom-forming cyanobacterial species and genetic variations, to reveal the characteristics of their development, cyanotoxin composition change, and competition under field and laboratory conditions.
Cyanobacteria are the oldest photosynthesizing prokaryotic organisms on earth, causing “blooms” in water bodies in Europe and other countries. Water “blooms” have recently become one of the most urgent conservation problems. They reduce the suitability of water resources for drinking water and recreation, cause economic losses, disrupt the functioning of aquatic ecosystems, can be the cause of poisoning, various diseases, and human or animal death.
In recent decades, increased nutrient supply accelerated eutrophication processes, leading to changes in cyanobacterial communities and “blooms” in aquatic ecosystems. Global warming and anthropogenic eutrophication are currently the major concerns. Rising temperatures have significant impacts on phytoplankton communities and promote the establishment of alien species. Synergy of experimental research in nature and in the laboratory is important to understand and predict the further influence of changing environmental factors on aquatic “bloom” development and alien cyanobacterial establishment of alien cyanobacteria. The number of invasive microbial species in water is increasing, but little is known about the factors driving this process. In recent decades, the alien species Raphidiopsis raciborskii, Sphaerospermopsis aphanizomenoides, and Chrysosporum bergii have begun to spread in Lithuanian waters. The rate of spread of these species varies and may depend on the effects of environmental factors, the structure of the dominant local cyanobacteria, and the genetic characteristics of the alien species themselves, the ability to synthesize secondary metabolites. The 2030 Biodiversity Strategy adopted by the European Union highlights the threat to biodiversity and ecosystem functioning posed by invasive alien species.
1. Investigate the diversity and productivity of bloom-causing alien and native, potentially toxic cyanobacterial species in eutrophic lakes.
2. Assess diversity and quantity changes of cyanotoxins and other secondary metabolites during the vegetation period of cyanobacteria.
3. Establish and maintain a collection of cultures of alien and local dominant cyanobacterial species.
4. Use genetic and chemical (PCR, chromatography) methods to evaluate the ability of isolated strains to synthesize secondary metabolites.
5. Evaluate the effect of temperature, nutrients, and light on the growth of native and alien cyanobacterial species, the amount of cyanotoxins, and interspecific competition under experimental conditions.
Methods and equipment:
– Assessment of environmental conditions (in situ universal portable meter MultiLine F/Set-3, Secchi disk, echosounder Eagle Cuda 168, multiparametric zone Aquaread);
– Quantitative analysis of N, P and their forms is determined according to the standards LST EN ISO 10304; LST EN ISO 14911; ISO 8245:2003 (Water Research UAB);
– identification of species (light microscope, PCR, sequencing),
– biosynthesis of secondary metabolites (ELISA, HPLC),
– search for functional genes (PCR, sequencing),
– laboratory studies on the influence of competition and environmental conditions (controlled environment equipment, fluorimeter).
1) A complex study of aquatic “blooms” will reveal the potential for the spread and invasion of alien cyanobacterial species and the impact on native phytoplankton communities.
2) New fundamental scientific knowledge will be gained about the essential regularities of aquatic ecosystems and their structure, functioning and evolution, necessary for understanding and predicting the development of Lithuanian ecosystems under conditions of global change and increasing anthropogenic impacts.
Global changes, climate warming and anthropogenic eutrophication, mainly affect shallow mid-latitude lakes and promote the intensive development of cyanobacteria, exacerbating the emerging water management problems of these ecosystems. The proposed dissertation topic will ensure synergy between the fundamental and applied research areas of algology. The results of the dissertation will make an important contribution to the management of risks associated with recreational exposure to toxins synthesized by cyanobacteria. In developing recommendations for the management of aquatic “blooms”, it is necessary to consider the complexity of the problem and combine in situ and experimental research results.
- 2021. 10 – 2021. 12 Internship in the Synthetic Organic Chemistry Laboratory, Institute of Natural Products and Agrobiology (Instituto de Producto Naturales y Agrobiologia, IPNA), Tenerife, Spain.
- Šuikaitė I., Koreivienė J., Karosienė J. 2022. “Alien species Raphidiopsis raciborskii, Crysosporum bergii and Sphaerospermopsis aphanizomenoides in the cyanobacteria community of two hypereutrophic Lithuanian lakes”. – 22nd Symposium of “The International Association of Cyanohyte/Cyanobacteria Research”, August 14-18, České Budějovice, Czech Republic. https://www.iac2022.cz/home.