# Review on Cyanobacterial Studies in Portugal: Current Impacts and Research Needs
## 1 Introduction  
Cyanobacteria belong to an ancient group of prokaryotes where its toxic risks have not been completely evaluated. Eutrophication, anthropogenic pressure, rise of temperature are factors that contribute to the proliferation of these microorganisms (CyanoHAB's) in aquatic systems interfering with water quality and public health by the release of odor substances and toxic compounds (cyanotoxins). These latter possess negative effects such as hepatotoxic, cytotoxic, neurotoxic, genotoxic, immunologic and carcinogenic having resulted in episodes of human and animal mortality as well as morbidity in several countries worldwide [1; 2; 3; 4; 5]. Cyanobacteria occurrence possess its main impacts on freshwater ecosystems since activities such as drinking, irrigation and recreation can result in public health problems and derived economic losses. In Portugal, studies on cyanobacteria began in the 1930s mainly through taxonomic studies, followed by some reported toxic episodes associated with blooms and finally, in 1989 the first toxic cyanobacterium species was isolated and its cyanotoxin amount determined. Other strains were also isolated contributing to the knowledge on toxic cyanobacteria occurrence in Portuguese freshwater ecosystems. Bloom occurrence is not often accounted for by national and European governmental agencies where surveillance encompasses solely phytoplankton counting and enumeration of microccystins variant LR the only regulated cyanotoxin in Portugal and Europe [6]. Although other cyanotoxins such as cylindrospermopsins, anatoxins andsaxitoxins occurrence have been found in Portuguese freshwater systems [7] the lack of regulations on these cyanotoxins by Portuguese governmental authorities reflects the need for further research in order to fully assess cyanobacterial impacts, include in monitoring campaigns the evaluation of other cyanotoxins besides the legislated microcystins [6] to improve water management, water quality and provide with recommendations to national authorities in case of an episode of cyanotoxins intoxication occurring. In toxic cyanobacteria and in cyanotoxins occurrence there can be applied quantitative and qualitative methods. The first (quantitative) allow the enumeration of the cyanotoxins applying techniques such as the High Performance Liquid Chromatography (HPLC), Liquid Chromatography-Mass Spectrometry (LC-MS) and Enzyme-Linked Immunosorbent Assay (ELISA) directly from isolates or environmental samples (water) that will permit after confronting the measured value with the adopted guideline value the evaluation of the toxic status of a given isolate or ecosystem. Matrix-Assisted Laser Desorption/Ionization (MALDI) is another used chemical method that aims to unravel the profile of cyanotoxicity and cyanobacteria metabolites in a given sample. The second (qualitative) allows the characterization and identification applying techniques such as the Polymerase Chain Reaction (PCR) and multiplex Polymerase Chain Reaction (mPCR) of toxic genotypes. These after DNA sequencing allow inferring of the phylogeny of given taxa. Other methods such as the quantitative PCR or Real-Time PCR permit the quantification of the toxic genotypes. Other used assays include the in vivo and in vitro assays based in experiments that englobe either living organisms (in vivo) or cell lines (in vitro) that after an incubation period to a given concentration of a cyanotoxin infer on the damage of the tested cyanotoxin. The present review summarizes the current research, impacts and future needs in cyanobacterial studies undertaken in Portugal (Table 1), contributing to redirect the continuous investigations globally by enumerating current impacts usually associated with cyanobacterial contamination and to foster the mitigation of toxic CyanoHABs, reinforce investigations in Portugal and worldwide by establishing research needs consequently turning the national and international communities and governments more resilient to this problem.