Filamentous, nitrogen-fixing cyanobacteria form extensive summer blooms in the Baltic Sea. Their ability to fix dissolved N2 allows cyanobacteria to circumvent the general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for the food web. However, the fate of the nitrogen fixed by cyanobacteria remains unresolved, as does its importance for secondary pro...

BACKGROUND Freshwater cyanobacteria are common inhabitants of recreational waterbodies throughout the world; some cyanobacteria can dominate the phytoplankton and form blooms, many of which are toxic. Numerous reports in the literature describe pruritic skin rashes after recreational or occupational exposure to cyanobacteria, but there has been little research conducted on the cutaneous effects...

Cyanobacteria are among the most ancient of evolutionary lineages, oxygenic photosynthesizers that may have originated before 3.0 Ga, as evidenced by free oxygen levels. Throughout the Precambrian, cyanobacteria were one of the most important drivers of biological innovations, strongly impacting early Earth's environments. At the end of the Archean Eon, they were responsible for the rapid oxyge...

Terpenes, a large family of natural products with important applications, are commonly associated with plants and fungi. The diterpenoids dehydroabietic and abietic acids are defense metabolites abundant in resin, and are used as biomarkers for conifer plants. We report here for the first time that the two diterpenoid acids are produced by members of several genera of cyanobacteria. Dehydroabie...

The heterocystous cyanobacteria are currently placed in subsections IV and V, which are distinguished by cellular division in one plane (false branching) and in more than one plane (true branching), respectively. Published phylogenies of 16S rRNA gene sequence data support the monophyly of the heterocystous cyanobacteria, with members of subsection V embedded within subsection IV. It has been p...

Cyanobacteria evolved as ubiquitous photosynthetic oxygen evolving prokaryotes, which owing to their limited motility are compelled to be exposed to the extremes of environmental stress conditions including oxidative stress prevailing at their natural habitats. Cyanobacteria possess an array of protective and repair mechanisms comprising of enzymatic and non-enzymatic antioxidants as natural ar...

Features of cyanobacteria are introduced for non-specialists by highlighting topics in the various chapters. Aspects where much more is known now than a decade ago are pointed out, such as the importance of cyanobacterial nitrogen fi xation in the oceans. This is followed by an account of the recent molecular studies most relevant for ecologists, especially topics not mentioned elsewhere in the...

We quantified within-species variation in the tolerance of the large, lake-dwelling daphnid, Daphnia pulicaria, to toxic cyanobacteria in the diet. Juvenile growth rates on diets consisting of 100% Ankistrodesmus falcatus (a nutritious green alga) or 100% Microcystis aeruginosa (toxic) were compared for D. pulicaria clones isolated from lakes expected to have low and high levels of bloom-formin...

Cyanobacteria contribute a significant portion to the annual oxygen yield and play important roles in biogeochemical cycles, e.g., as major primary producers. Due their photosynthetic lifestyle, cyanobacteria also arouse interest hosts for sustainable production of fuel components high-value chemicals.